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diff --git a/doc/rfc/rfc3665.txt b/doc/rfc/rfc3665.txt new file mode 100644 index 0000000..09b5d69 --- /dev/null +++ b/doc/rfc/rfc3665.txt @@ -0,0 +1,5267 @@ + + + + + + +Network Working Group A. Johnston +Request for Comments: 3665 MCI +BCP: 75 S. Donovan +Category: Best Current Practice R. Sparks + C. Cunningham + dynamicsoft + K. Summers + Sonus + December 2003 + + + Session Initiation Protocol (SIP) Basic Call Flow Examples + +Status of this Memo + + This document specifies an Internet Best Current Practices for the + Internet Community, and requests discussion and suggestions for + improvements. Distribution of this memo is unlimited. + +Copyright Notice + + Copyright (C) The Internet Society (2003). All Rights Reserved. + +Abstract + + This document gives examples of Session Initiation Protocol (SIP) + call flows. Elements in these call flows include SIP User Agents and + Clients, SIP Proxy and Redirect Servers. Scenarios include SIP + Registration and SIP session establishment. Call flow diagrams and + message details are shown. + + + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 1] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +Table of Contents + + 1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 + 1.1. General Assumptions. . . . . . . . . . . . . . . . . . . 3 + 1.2. Legend for Message Flows . . . . . . . . . . . . . . . . 3 + 1.3. SIP Protocol Assumptions . . . . . . . . . . . . . . . . 4 + 2. SIP Registration . . . . . . . . . . . . . . . . . . . . . . . 4 + 2.1. Successful New Registration. . . . . . . . . . . . . . . 5 + 2.2. Update of Contact List . . . . . . . . . . . . . . . . . 7 + 2.3. Request for Current Contact List . . . . . . . . . . . . 8 + 2.4. Cancellation of Registration . . . . . . . . . . . . . . 9 + 2.5. Unsuccessful Registration. . . . . . . . . . . . . . . . 10 + 3. SIP Session Establishment. . . . . . . . . . . . . . . . . . . 12 + 3.1. Successful Session Establishment . . . . . . . . . . . . 12 + 3.2. Session Establishment Through Two Proxies. . . . . . . . 15 + 3.3. Session with Multiple Proxy Authentication . . . . . . . 26 + 3.4. Successful Session with Proxy Failure. . . . . . . . . . 37 + 3.5. Session Through a SIP ALG. . . . . . . . . . . . . . . . 46 + 3.6. Session via Redirect and Proxy Servers with SDP in ACK . 54 + 3.7. Session with re-INVITE (IP Address Change) . . . . . . . 61 + 3.8. Unsuccessful No Answer . . . . . . . . . . . . . . . . . 67 + 3.9. Unsuccessful Busy. . . . . . . . . . . . . . . . . . . . 75 + 3.10. Unsuccessful No Response from User Agent . . . . . . . . 80 + 3.11. Unsuccessful Temporarily Unavailable . . . . . . . . . . 85 + 4. Security Considerations. . . . . . . . . . . . . . . . . . . . 91 + 5. References . . . . . . . . . . . . . . . . . . . . . . . . . . 91 + 5.1. Normative References . . . . . . . . . . . . . . . . . . 91 + 5.2. Informative References . . . . . . . . . . . . . . . . . 91 + 6. Intellectual Property Statement. . . . . . . . . . . . . . . . 91 + 7. Acknowledgments. . . . . . . . . . . . . . . . . . . . . . . . 92 + 8. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 93 + 9. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 94 + +1. Overview + + The call flows shown in this document were developed in the design of + a SIP IP communications network. They represent an example minimum + set of functionality. + + It is the hope of the authors that this document will be useful for + SIP implementers, designers, and protocol researchers alike and will + help further the goal of a standard implementation of RFC 3261 [1]. + These flows represent carefully checked and working group reviewed + scenarios of the most basic examples as a companion to the + specifications. + + + + + + +Johnston, et al. Best Current Practice [Page 2] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + These call flows are based on the current version 2.0 of SIP in RFC + 3261 [1] with SDP usage described in RFC 3264 [2]. Other RFCs also + comprise the SIP standard but are not used in this set of basic call + flows. + + Call flow examples of SIP interworking with the PSTN through gateways + are contained in a companion document, RFC 3666 [5]. + + The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", + "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this + document are to be interpreted as described in BCP 14, RFC 2119 [4]. + +1.1. General Assumptions + + A number of architecture, network, and protocol assumptions underlie + the call flows in this document. Note that these assumptions are not + requirements. They are outlined in this section so that they may be + taken into consideration and to aid in the understanding of the call + flow examples. + + The authentication of SIP User Agents in these example call flows is + performed using HTTP Digest as defined in [1] and [3]. + + Some Proxy Servers in these call flows insert Record-Route headers + into requests to ensure that they are in the signaling path for + future message exchanges. + + These flows show TCP, TLS, and UDP for transport. See the discussion + in RFC 3261 for details on the transport issues for SIP. + +1.2. Legend for Message Flows + + Dashed lines (---) represent signaling messages that are mandatory to + the call scenario. These messages can be SIP or PSTN signaling. The + arrow indicates the direction of message flow. + + Double dashed lines (===) represent media paths between network + elements. + + Messages with parentheses around their name represent optional + messages. + + Messages are identified in the Figures as F1, F2, etc. This + references the message details in the list that follows the Figure. + Comments in the message details are shown in the following form: + + /* Comments. */ + + + + +Johnston, et al. Best Current Practice [Page 3] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +1.3. SIP Protocol Assumptions + + This document does not prescribe the flows precisely as they are + shown, but rather the flows illustrate the principles for best + practice. They are best practices usages (orderings, syntax, + selection of features for the purpose, handling of error) of SIP + methods, headers and parameters. IMPORTANT: The exact flows here + must not be copied as is by an implementer due to specific incorrect + characteristics that were introduced into the document for + convenience and are listed below. To sum up, the basic flows + represent well-reviewed examples of SIP usage, which are best common + practice according to IETF consensus. + + For simplicity in reading and editing the document, there are a + number of differences between some of the examples and actual SIP + messages. For example, the HTTP Digest responses are not actual MD5 + encodings. Call-IDs are often repeated, and CSeq counts often begin + at 1. Header fields are usually shown in the same order. Usually + only the minimum required header field set is shown, others that + would normally be present such as Accept, Supported, Allow, etc are + not shown. + + Actors: + + Element Display Name URI IP Address + ------- ------------ --- ---------- + + User Agent Alice alice@atlanta.example.com 192.0.2.101 + User Agent Bob bob@biloxi.example.com 192.0.2.201 + User Agent bob@chicago.example.com 192.0.2.100 + Proxy Server ss1.atlanta.example.com 192.0.2.111 + Proxy/Registrar ss2.biloxi.example.com 192.0.2.222 + Proxy Server ss3.chicago.example.com 192.0.2.233 + ALG alg1.atlanta.example.com 192.0.2.128 + +2. SIP Registration + + Registration binds a particular device Contact URI with a SIP user + Address of Record (AOR). + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 4] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +2.1. Successful New Registration + + Bob SIP Server + | | + | REGISTER F1 | + |------------------------------>| + | 401 Unauthorized F2 | + |<------------------------------| + | REGISTER F3 | + |------------------------------>| + | 200 OK F4 | + |<------------------------------| + | | + + Bob sends a SIP REGISTER request to the SIP server. The request + includes the user's contact list. This flow shows the use of HTTP + Digest for authentication using TLS transport. TLS transport is used + due to the lack of integrity protection in HTTP Digest and the danger + of registration hijacking without it, as described in RFC 3261 [1]. + The SIP server provides a challenge to Bob. Bob enters her/his valid + user ID and password. Bob's SIP client encrypts the user information + according to the challenge issued by the SIP server and sends the + response to the SIP server. The SIP server validates the user's + credentials. It registers the user in its contact database and + returns a response (200 OK) to Bob's SIP client. The response + includes the user's current contact list in Contact headers. The + format of the authentication shown is HTTP digest. It is assumed + that Bob has not previously registered with this Server. + + Message Details + + F1 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Contact: <sips:bob@client.biloxi.example.com> + Content-Length: 0 + + + + + + + + + +Johnston, et al. Best Current Practice [Page 5] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F2 401 Unauthorized SIP Server -> Bob + + SIP/2.0 401 Unauthorized + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com>;tag=1410948204 + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + WWW-Authenticate: Digest realm="atlanta.example.com", qop="auth", + nonce="ea9c8e88df84f1cec4341ae6cbe5a359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + F3 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashd92 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=ja743ks76zlflH + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 2 REGISTER + Contact: <sips:bob@client.biloxi.example.com> + Authorization: Digest username="bob", realm="atlanta.example.com" + nonce="ea9c8e88df84f1cec4341ae6cbe5a359", opaque="", + uri="sips:ss2.biloxi.example.com", + response="dfe56131d1958046689d83306477ecc" + Content-Length: 0 + + + F4 200 OK SIP Server -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashd92 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=ja743ks76zlflH + To: Bob <sips:bob@biloxi.example.com>;tag=37GkEhwl6 + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 2 REGISTER + Contact: <sips:bob@client.biloxi.example.com>;expires=3600 + Content-Length: 0 + + + + + + + + +Johnston, et al. Best Current Practice [Page 6] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +2.2. Update of Contact List + + Bob SIP Server + | | + | REGISTER F1 | + |------------------------------>| + | 200 OK F2 | + |<------------------------------| + | | + + Bob wishes to update the list of addresses where the SIP server will + redirect or forward INVITE requests. + + Bob sends a SIP REGISTER request to the SIP server. Bob's request + includes an updated contact list. Since the user already has + authenticated with the server, the user supplies authentication + credentials with the request and is not challenged by the server. The + SIP server validates the user's credentials. It registers the user + in its contact database, updates the user's contact list, and returns + a response (200 OK) to Bob's SIP client. The response includes the + user's current contact list in Contact headers. + + Message Details + + F1 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Contact: mailto:bob@biloxi.example.com + Authorization: Digest username="bob", realm="atlanta.example.com", + qop="auth", nonce="1cec4341ae6cbe5a359ea9c8e88df84f", opaque="", + uri="sips:ss2.biloxi.example.com", + response="71ba27c64bd01de719686aa4590d5824" + Content-Length: 0 + + + F2 200 OK SIP Server -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com>;tag=34095828jh + + + +Johnston, et al. Best Current Practice [Page 7] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Contact: <sips:bob@client.biloxi.example.com>;expires=3600 + Contact: <mailto:bob@biloxi.example.com>;expires=4294967295 + Content-Length: 0 + +2.3. Request for Current Contact List + + Bob SIP Server + | | + | REGISTER F1 | + |------------------------------>| + | 200 OK F2 | + |<------------------------------| + | | + + Bob sends a register request to the Proxy Server containing no + Contact headers, indicating the user wishes to query the server for + the user's current contact list. Since the user already has + authenticated with the server, the user supplies authentication + credentials with the request and is not challenged by the server. + The SIP server validates the user's credentials. The server returns + a response (200 OK) which includes the user's current registration + list in Contact headers. + + Message Details + + F1 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Authorization: Digest username="bob", realm="atlanta.example.com", + nonce="df84f1cec4341ae6cbe5ap359a9c8e88", opaque="", + uri="sips:ss2.biloxi.example.com", + response="aa7ab4678258377c6f7d4be6087e2f60" + Content-Length: 0 + + + F2 200 OK SIP Server -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + + + +Johnston, et al. Best Current Practice [Page 8] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com>;tag=jqoiweu75 + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Contact: <sips:bob@client.biloxi.example.com>;expires=3600 + Contact: <mailto:bob@biloxi.example.com>;expires=4294967295 + Content-Length: 0 + +2.4. Cancellation of Registration + + Bob SIP Server + | | + | REGISTER F1 | + |------------------------------>| + | 200 OK F2 | + |<------------------------------| + | | + + Bob wishes to cancel their registration with the SIP server. Bob + sends a SIP REGISTER request to the SIP server. The request has an + expiration period of 0 and applies to all existing contact locations. + Since the user already has authenticated with the server, the user + supplies authentication credentials with the request and is not + challenged by the server. The SIP server validates the user's + credentials. It clears the user's contact list, and returns a + response (200 OK) to Bob's SIP client. + + Message Details + + F1 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Expires: 0 + Contact: * + Authorization: Digest username="bob", realm="atlanta.example.com", + nonce="88df84f1cac4341aea9c8ee6cbe5a359", opaque="", + uri="sips:ss2.biloxi.example.com", + response="ff0437c51696f9a76244f0cf1dbabbea" + Content-Length: 0 + + + F2 200 OK SIP Server -> Bob + + + +Johnston, et al. Best Current Practice [Page 9] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + SIP/2.0 200 OK + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com>;tag=1418nmdsrf + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Content-Length: 0 + +2.5. Unsuccessful Registration + + Bob SIP Server + | | + | REGISTER F1 | + |------------------------------>| + | 401 Unauthorized F2 | + |<------------------------------| + | REGISTER F3 | + |------------------------------>| + | 401 Unauthorized F4 | + |<------------------------------| + | | + + Bob sends a SIP REGISTER request to the SIP Server. The SIP server + provides a challenge to Bob. Bob enters her/his user ID and + password. Bob's SIP client encrypts the user information according + to the challenge issued by the SIP server and sends the response to + the SIP server. The SIP server attempts to validate the user's + credentials, but they are not valid (the user's password does not + match the password established for the user's account). The server + returns a response (401 Unauthorized) to Bob's SIP client. + + Message Details + + F1 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + Contact: <sips:bob@client.biloxi.example.com> + Content-Length: 0 + + + + + +Johnston, et al. Best Current Practice [Page 10] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F2 Unauthorized SIP Server -> Bob + + SIP/2.0 401 Unauthorized + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=a73kszlfl + To: Bob <sips:bob@biloxi.example.com>;tag=1410948204 + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 1 REGISTER + WWW-Authenticate: Digest realm="atlanta.example.com", qop="auth", + nonce="f1cec4341ae6ca9c8e88df84be55a359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + F3 REGISTER Bob -> SIP Server + + REGISTER sips:ss2.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashd92 + Max-Forwards: 70 + From: Bob <sips:bob@biloxi.example.com>;tag=JueHGuidj28dfga + To: Bob <sips:bob@biloxi.example.com> + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 2 REGISTER + Contact: <sips:bob@client.biloxi.example.com> + Authorization: Digest username="bob", realm="atlanta.example.com", + nonce="f1cec4341ae6ca9c8e88df84be55a359", opaque="", + uri="sips:ss2.biloxi.example.com", + response="61f8470ceb87d7ebf508220214ed438b" + Content-Length: 0 + + /* The response above encodes the incorrect password */ + + + F4 401 Unauthorized SIP Server -> Bob + + SIP/2.0 401 Unauthorized + Via: SIP/2.0/TLS client.biloxi.example.com:5061;branch=z9hG4bKnashd92 + ;received=192.0.2.201 + From: Bob <sips:bob@biloxi.example.com>;tag=JueHGuidj28dfga + To: Bob <sips:bob@biloxi.example.com>;tag=1410948204 + Call-ID: 1j9FpLxk3uxtm8tn@biloxi.example.com + CSeq: 2 REGISTER + WWW-Authenticate: Digest realm="atlanta.example.com", qop="auth", + nonce="84f1c1ae6cbe5ua9c8e88dfa3ecm3459", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + + +Johnston, et al. Best Current Practice [Page 11] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3. SIP Session Establishment + + This section details session establishment between two SIP User + Agents (UAs): Alice and Bob. Alice (sip:alice@atlanta.example.com) + and Bob (sip:bob@biloxi.example.com) are assumed to be SIP phones or + SIP-enabled devices. The successful calls show the initial + signaling, the exchange of media information in the form of SDP + payloads, the establishment of the media session, then finally the + termination of the call. + + HTTP Digest authentication is used by Proxy Servers to authenticate + the caller Alice. It is assumed that Bob has registered with Proxy + Server Proxy 2 as per Section 2 to be able to receive the calls via + the Proxy. + +3.1. Successful Session Establishment + + Alice Bob + | | + | INVITE F1 | + |----------------------->| + | 180 Ringing F2 | + |<-----------------------| + | | + | 200 OK F3 | + |<-----------------------| + | ACK F4 | + |----------------------->| + | Both Way RTP Media | + |<======================>| + | | + | BYE F5 | + |<-----------------------| + | 200 OK F6 | + |----------------------->| + | | + + In this scenario, Alice completes a call to Bob directly. + + Message Details + + F1 INVITE Alice -> Bob + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + + + +Johnston, et al. Best Current Practice [Page 12] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F2 180 Ringing Bob -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=8321234356 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + Content-Length: 0 + + + F3 200 OK Bob -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=8321234356 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + +Johnston, et al. Best Current Practice [Page 13] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + + F4 ACK Alice -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bd5 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=8321234356 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + /* RTP streams are established between Alice and Bob */ + + /* Bob Hangs Up with Alice. Note that the CSeq is NOT 2, since + Alice and Bob maintain their own independent CSeq counts. + (The INVITE was request 1 generated by Alice, and the BYE is + request 1 generated by Bob) */ + + + F5 BYE Bob -> Alice + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + Max-Forwards: 70 + From: Bob <sip:bob@biloxi.example.com>;tag=8321234356 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F6 200 OK Alice -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sip:bob@biloxi.example.com>;tag=8321234356 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + + + + +Johnston, et al. Best Current Practice [Page 14] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.2. Session Establishment Through Two Proxies + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| | | + | 407 F2 | | | + |<---------------| | | + | ACK F3 | | | + |--------------->| | | + | INVITE F4 | | | + |--------------->| INVITE F5 | | + | 100 F6 |--------------->| INVITE F7 | + |<---------------| 100 F8 |--------------->| + | |<---------------| | + | | | 180 F9 | + | | 180 F10 |<---------------| + | 180 F11 |<---------------| | + |<---------------| | 200 F12 | + | | 200 F13 |<---------------| + | 200 F14 |<---------------| | + |<---------------| | | + | ACK F15 | | | + |--------------->| ACK F16 | | + | |--------------->| ACK F17 | + | | |--------------->| + | Both Way RTP Media | + |<================================================>| + | | | BYE F18 | + | | BYE F19 |<---------------| + | BYE F20 |<---------------| | + |<---------------| | | + | 200 F21 | | | + |--------------->| 200 F22 | | + | |--------------->| 200 F23 | + | | |--------------->| + | | | | + + In this scenario, Alice completes a call to Bob using two proxies + Proxy 1 and Proxy 2. The initial INVITE (F1) contains a pre-loaded + Route header with the address of Proxy 1 (Proxy 1 is configured as a + default outbound proxy for Alice). The request does not contain the + Authorization credentials Proxy 1 requires, so a 407 Proxy + Authorization response is sent containing the challenge information. + A new INVITE (F4) is then sent containing the correct credentials and + the call proceeds. The call terminates when Bob disconnects by + initiating a BYE message. + + + + +Johnston, et al. Best Current Practice [Page 15] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Proxy 1 inserts a Record-Route header into the INVITE message to + ensure that it is present in all subsequent message exchanges. Proxy + 2 also inserts itself into the Record-Route header. The ACK (F15) + and BYE (F18) both have a Route header. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b43 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 1 challenges Alice for authentication */ + + + F2 407 Proxy Authorization Required Proxy 1 -> Alice + + SIP/2.0 407 Proxy Authorization Required + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b43 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=3flal12sf + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 INVITE + Proxy-Authenticate: Digest realm="atlanta.example.com", qop="auth", + nonce="f84f1cec41e6cbe5aea9c8e88d359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + + + + +Johnston, et al. Best Current Practice [Page 16] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F3 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b43 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=3flal12sf + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + /* Alice responds be re-sending the INVITE with authentication + credentials in it. */ + + + F4 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", + response="42ce3cef44b22f50c6a6071bc8" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 1 accepts the credentials and forwards the INVITE to Proxy + 2. Client for Alice prepares to receive data on port 49172 from the + network. */ + + + + + + +Johnston, et al. Best Current Practice [Page 17] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F5 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F6 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Content-Length: 0 + + + F7 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + + + +Johnston, et al. Best Current Practice [Page 18] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F8 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Content-Length: 0 + + + F9 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + CSeq: 2 INVITE + Content-Length: 0 + + + +Johnston, et al. Best Current Practice [Page 19] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + F10 180 Ringing Proxy 2 -> Proxy 1 + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + CSeq: 2 INVITE + Content-Length: 0 + + + F11 180 Ringing Proxy 1 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + CSeq: 2 INVITE + Content-Length: 0 + + + F12 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + + + +Johnston, et al. Best Current Practice [Page 20] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F13 200 OK Proxy 2 -> Proxy 1 + + SIP/2.0 200 OK + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F14 200 OK Proxy 1 -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + + + +Johnston, et al. Best Current Practice [Page 21] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F15 ACK Alice -> Proxy 1 + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b76 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr>, + <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 ACK + Content-Length: 0 + + + F16 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b76 + ;received=192.0.2.101 + Max-Forwards: 69 + Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 ACK + Content-Length: 0 + + + F17 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + + + +Johnston, et al. Best Current Practice [Page 22] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74b76 + ;received=192.0.2.101 + Max-Forwards: 68 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 2 ACK + Content-Length: 0 + + /* RTP streams are established between Alice and Bob */ + + /* Bob Hangs Up with Alice. */ + + /* Again, note that the CSeq is NOT 3. Alice and Bob maintain + their own separate CSeq counts */ + + + F18 BYE Bob -> Proxy 2 + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + Max-Forwards: 70 + Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F19 BYE Proxy 2 -> Proxy 1 + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + Max-Forwards: 69 + Route: <sip:ss1.atlanta.example.com;lr> + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + +Johnston, et al. Best Current Practice [Page 23] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F20 BYE Proxy 1 -> Alice + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + Max-Forwards: 68 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F21 200 OK Alice -> Proxy 1 + + SIP/2.0 200 OK + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F22 200 OK Proxy 1 -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.101 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + + + +Johnston, et al. Best Current Practice [Page 24] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F23 200 OK Proxy 2 -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 3848276298220188511@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 25] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.3. Session with Multiple Proxy Authentication + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |----------->| | | + | 407 Proxy Authorization Required F2 | + |<-----------| | | + | ACK F3 | | | + |----------->| | | + | INVITE F4 | | | + |----------->| | | + | 100 F5 | | | + |<-----------| INVITE F6 | | + | |---------->| | + | | 407 Proxy Authorization Required F7 + | |<----------| | + | | ACK F8 | | + | |---------->| | + | 407 Proxy Authorization Required F9 | + |<-----------| | | + | ACK F10 | | | + |----------->| | | + | INVITE F11| | | + |----------->| | | + | 100 F12 | | | + |<-----------| INVITE F13| | + | |---------->| | + | | 100 F14 | | + | |<----------| INVITE F15 | + | | |------------>| + | | | 200 OK F16 | + | | 200 OK F17|<------------| + | 200 OK F18 |<----------| | + |<-----------| | | + | ACK F19 | | | + |----------->| ACK F20 | | + | |---------->| ACK F21 | + | | |------------>| + | RTP Media Path | + |<====================================>| + + In this scenario, Alice completes a call to Bob using two proxies + Proxy 1 and Proxy 2. Alice has valid credentials in both domains. + Since the initial INVITE (F1) does not contain the Authorization + credentials Proxy 1 requires, so a 407 Proxy Authorization response + is sent containing the challenge information. A new INVITE (F4) is + + + + +Johnston, et al. Best Current Practice [Page 26] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + then sent containing the correct credentials and the call proceeds + after Proxy 2 challenges and receives valid credentials. The call + terminates when Bob disconnects by initiating a BYE message. + + Proxy 1 inserts a Record-Route header into the INVITE message to + ensure that it is present in all subsequent message exchanges. Proxy + 2 also inserts itself into the Record-Route header. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b03 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 1 challenges Alice for authentication */ + + + F2 407 Proxy Authorization Required Proxy 1 -> Alice + + SIP/2.0 407 Proxy Authorization Required + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b03 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=876321 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Proxy-Authenticate: Digest realm="atlanta.example.com", qop="auth", + nonce="wf84f1cczx41ae6cbeaea9ce88d359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + +Johnston, et al. Best Current Practice [Page 27] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + + F3 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Max-Forwards: 70 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b03 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=876321 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + /* Alice responds be re-sending the INVITE with authentication + credentials in it. The same Call-ID is used, so the CSeq is + increased. */ + + + F4 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", + response="42ce3cef44b22f50c6a6071bc8" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 1 accepts the credentials and forwards the INVITE to Proxy + 2. Client for Alice prepares to receive data on port 49172 from the + network. */ + + + +Johnston, et al. Best Current Practice [Page 28] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + F5 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Content-Length: 0 + + + F6 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 2 challenges Alice for authentication */ + + + F7 407 Proxy Authorization Required Proxy 2 -> Proxy 1 + + SIP/2.0 407 Proxy Authorization Required + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + ;received=192.0.2.101 + + + + +Johnston, et al. Best Current Practice [Page 29] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=838209 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Proxy-Authenticate: Digest realm="biloxi.example.com", qop="auth", + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + F8 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=838209 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 ACK + Content-Length: 0 + + /* Proxy 1 forwards the challenge to Alice for authentication from + Proxy 2 */ + + + F9 407 Proxy Authorization Required Proxy 1 -> Alice + + SIP/2.0 407 Proxy Authorization Required + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=838209 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Proxy-Authenticate: Digest realm="biloxi.example.com", qop="auth", + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + F10 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b21 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=838209 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + + + +Johnston, et al. Best Current Practice [Page 30] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + CSeq: 2 ACK + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", + response="42ce3cef44b22f50c6a6071bc8" + Content-Length: 0 + + /* Alice responds be re-sending the INVITE with authentication + credentials for Proxy 1 AND Proxy 2. */ + + + F11 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", + response="42ce3cef44b22f50c6a6071bc8" + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", response="f44ab22f150c6a56071bce8" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 1 finds its credentials and authorizes Alice, forwarding the + INVITE to Proxy. */ + + + + + + + +Johnston, et al. Best Current Practice [Page 31] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F12 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Content-Length: 0 + + + F13 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", response="f44ab22f150c6a56071bce8" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 2 finds its credentials and authorizes Alice, forwarding the + INVITE to Bob. */ + + + + + + + + + +Johnston, et al. Best Current Practice [Page 32] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F14 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Content-Length: 0 + + + F15 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK31972.1 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Bob answers the call immediately */ + + + + + + + + + +Johnston, et al. Best Current Practice [Page 33] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F16 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK31972.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F17 200 OK Proxy 2 -> Proxy 1 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + + + +Johnston, et al. Best Current Practice [Page 34] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F18 200 OK Proxy 1 -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F19 ACK Alice -> Proxy 1 + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b44 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr>, + <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 ACK + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="wf84f1ceczx41ae6cbe5aea9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", + response="42ce3cef44b22f50c6a6071bc8" + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + + + +Johnston, et al. Best Current Practice [Page 35] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", response="f44ab22f150c6a56071bce8" + Content-Length: 0 + + + F20 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b44 + ;received=192.0.2.101 + Max-Forwards: 69 + Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 ACK + Contact: <sip:bob@client.biloxi.example.com> + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + nonce="c1e22c41ae6cbe5ae983a9c8e88d359", opaque="", + uri="sip:bob@biloxi.example.com", response="f44ab22f150c6a56071bce8" + Content-Length: 0 + + + F21 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK31972.1 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK230f2.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b44 + ;received=192.0.2.101 + Max-Forwards: 68 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=9103874 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 3 ACK + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 36] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.4. Successful Session with Proxy Failure + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| | | + | INVITE F2 | | | + |--------------->| | | + | INVITE F3 | | | + |--------------->| | | + | INVITE F4 | | | + |--------------->| | | + | INVITE F5 | | | + |--------------->| | | + | INVITE F6 | | | + |--------------->| | | + | INVITE F7 | | | + |--------------->| | | + | INVITE F8 | | + |-------------------------------->| | + | 407 F9 | | + |<--------------------------------| | + | ACK F10 | | + |-------------------------------->| | + | INVITE F11 | | + |-------------------------------->| INVITE F12 | + | 100 F13 |--------------->| + |<--------------------------------| | + | | 180 F14 | + | 180 F15 |<---------------| + |<--------------------------------| | + | | 200 F16 | + | 200 F17 |<---------------| + |<--------------------------------| | + | ACK F18 | | + |-------------------------------->| ACK F19 | + | |--------------->| + | Both Way RTP Media | + |<================================================>| + | | BYE F20 | + | BYE F21 |<---------------| + |<--------------------------------| | + | 200 F22 | | + |-------------------------------->| 200 F23 | + | |--------------->| + | | | + + + + + +Johnston, et al. Best Current Practice [Page 37] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + In this scenario, Alice completes a call to Bob via a Proxy Server. + Alice is configured for a primary SIP Proxy Server Proxy 1 and a + secondary SIP Proxy Server Proxy 2 (Or is able to use DNS SRV records + to locate Proxy 1 and Proxy 2). Alice has valid credentials for both + domains. Proxy 1 is out of service and does not respond to INVITEs + (it is reachable, but unresponsive). Alice then completes the call + to Bob using Proxy 2. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK465b6d + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F2 INVITE Alice -> Proxy 1 + + Same as Message F1 + + + F3 INVITE Alice -> Proxy 1 + + Same as Message F1 + + + F4 INVITE Alice -> Proxy 1 + + Same as Message F1 + + + + + +Johnston, et al. Best Current Practice [Page 38] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F5 INVITE Alice -> Proxy 1 + + Same as Message F1 + + + F6 INVITE Alice -> Proxy 1 + + Same as Message F1 + + + F7 INVITE Alice -> Proxy 1 + + Same as Message F1 + + /* Alice gives up on the unresponsive proxy */ + + + F8 INVITE Alice -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b8a + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Proxy 2 challenges Alice for authentication */ + + + F9 407 Proxy Authorization Required Proxy 2 -> Alice + + SIP/2.0 407 Proxy Authorization Required + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b8a + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=2421452 + + + +Johnston, et al. Best Current Practice [Page 39] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 INVITE + Proxy-Authenticate: Digest realm="biloxi.example.com", qop="auth", + nonce="1ae6cbe5ea9c8e8df84fqnlec434a359", + opaque="", stale=FALSE, algorithm=MD5 + Content-Length: 0 + + + F10 ACK Alice -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b8a + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=2421452 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + /* Alice responds by re-sending the INVITE with authentication + credentials in it. */ + + + F11 INVITE Alice -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + nonce="1ae6cbe5ea9c8e8df84fqnlec434a359", opaque="", + uri="sip:bob@biloxi.example.com", + response="8a880c919d1a52f20a1593e228adf599" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + +Johnston, et al. Best Current Practice [Page 40] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + /* Proxy 2 accepts the credentials and forwards the INVITE to Bob. + Client for Alice prepares to receive data on port 49172 from the + network. + */ + + + F12 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F13 100 Trying Proxy 2 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Content-Length: 0 + + + F14 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + + + +Johnston, et al. Best Current Practice [Page 41] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F15 180 Ringing Proxy 2 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F16 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + +Johnston, et al. Best Current Practice [Page 42] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + + F17 200 OK Proxy 2 -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F18 ACK Alice -> Proxy 2 + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b8g + Max-Forwards: 70 + Route: <sip:ss2.biloxi.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 2 ACK + Content-Length: 0 + + + F19 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b8g + ;received=192.0.2.101 + Max-Forwards: 69 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + + + +Johnston, et al. Best Current Practice [Page 43] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + CSeq: 2 ACK + Content-Length: 0 + + /* RTP streams are established between Alice and Bob */ + + /* Bob Hangs Up with Alice. */ + + + F20 BYE Bob -> Proxy 2 + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/UDP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + Max-Forwards: 70 + Route: <sip:ss2.biloxi.example.com;lr> + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F21 BYE Proxy 2 -> Alice + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + Max-Forwards: 69 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F22 200 OK Alice -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + +Johnston, et al. Best Current Practice [Page 44] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + F23 200 OK Proxy 2 -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.biloxi.example.com:5060;branch=z9hG4bKnashds7 + ;received=192.0.2.201 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 4Fde34wkd11wsGFDs3@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 45] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.5. Session Through a SIP ALG + + Alice ALG Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| INVITE F2 | | + | 100 F3 |--------------->| INVITE F4 | + |<---------------| 100 F5 |--------------->| + | |<---------------| 180 F6 | + | | 180 F7 |<---------------| + | 180 F8 |<---------------| | + |<---------------| | 200 F9 | + | | 200 F10 |<---------------| + | 200 F11 |<---------------| | + |<---------------| | + | ACK F12 | | + |--------------->| ACK F13 | + | |-------------------------------->| + | RTP Media | Both Way RTP Media | + |<==============>|<===============================>| + | BYE F14 | | + |--------------->| BYE F15 | + | |-------------------------------->| + | | 200 F16 | + | 200 F17 |<--------------------------------| + |<---------------| | + | | | + + Alice completes a call to Bob through a ALG (Application Layer + Gateway) and a SIP Proxy. The routing through the ALG is + accomplished using a pre-loaded Route header in the INVITE F1. Note + that the media stream setup is not end-to-end - the ALG terminates + both media streams and bridges them. This is done by the ALG + modifying the SDP in the INVITE (F1) and 200 OK (F10) messages, and + possibly any 18x or ACK messages containing SDP. + + In addition to firewall traversal, this Back-to-Back User Agent + (B2BUA) could be used as part of an anonymizer service (in which all + identifying information on Alice would be removed), or to perform + codec media conversion, such as mu-law to A-law conversion of PCM on + an international call. + + Also note that Proxy 2 does not Record-Route in this call flow. + + + + + + + + +Johnston, et al. Best Current Practice [Page 46] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Message Details + + F1 INVITE Alice -> SIP ALG + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Route: <sip:alg1.atlanta.example.com;lr> + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + nonce="85b4f1cen4341ae6cbe5a3a9c8e88df9", opaque="", + uri="sip:bob@biloxi.example.com", + response="b3f392f9218a328b9294076d708e6815" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* Client for Alice prepares to receive data on port 49172 from the + network. */ + + + F2 INVITE SIP ALG -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="biloxi.example.com", + + + +Johnston, et al. Best Current Practice [Page 47] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + nonce="85b4f1cen4341ae6cbe5a3a9c8e88df9", opaque="", + uri="sip:bob@biloxi.example.com", + response="b3f392f9218a328b9294076d708e6815" + Content-Type: application/sdp + Content-Length: 150 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.128 + t=0 0 + m=audio 2000 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F3 100 Trying SIP ALG -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + /* SIP ALG prepares to proxy data from port 192.0.2.128/2000 to + 192.0.2.101/49172. Proxy 2 uses a Location Service function to + determine where Bob is located. Based upon location analysis the call + is forwarded to Bob */ + + + F4 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + + + +Johnston, et al. Best Current Practice [Page 48] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Content-Length: 150 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.128 + t=0 0 + m=audio 2000 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F5 100 Trying Proxy 2 -> SIP ALG + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F6 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F7 180 Ringing Proxy 2 -> SIP ALG + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + + + +Johnston, et al. Best Current Practice [Page 49] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F8 180 Ringing SIP ALG -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F9 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + + + +Johnston, et al. Best Current Practice [Page 50] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F10 200 OK Proxy 2 -> SIP ALG + + SIP/2.0 200 OK + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F11 200 OK SIP ALG -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.128 + t=0 0 + + + +Johnston, et al. Best Current Practice [Page 51] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + m=audio 1734 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* The ALG prepares to proxy packets from 192.0.2.128/ + 1734 to 192.0.2.201/3456 */ + + + F12 ACK Alice -> SIP ALG + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bhh + Max-Forwards: 70 + Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F13 ACK SIP ALG -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bhh + ;received=192.0.2.101 + Max-Forwards: 69 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + /* RTP streams are established between Alice and the ALG and + between the ALG and B*/ + + /* Alice Hangs Up with Bob. */ + + + F14 BYE Alice -> SIP ALG + + BYE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74be5 + Max-Forwards: 70 + Route: <sip:alg1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + + + +Johnston, et al. Best Current Practice [Page 52] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + CSeq: 2 BYE + Content-Length: 0 + + + F15 BYE SIP ALG -> Bob + + BYE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74be5 + ;received=192.0.2.101 + Max-Forwards: 69 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 BYE + Content-Length: 0 + + + F16 200 OK Bob -> SIP ALG + + SIP/2.0 200 OK + Via: SIP/2.0/UDP alg1.atlanta.example.com:5060;branch=z9hG4bK739578.1 + ;received=192.0.2.128 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74be5 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 BYE + Content-Length: 0 + + + F17 200 OK SIP ALG -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74be5 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 BYE + Content-Length: 0 + + + + + + + + + +Johnston, et al. Best Current Practice [Page 53] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.6. Session via Redirect and Proxy Servers with SDP in ACK + + Alice Redirect Server Proxy 3 Bob + | | | | + | INVITE F1 | | | + |--------------->| | | + | 302 F2 | | | + |<---------------| | | + | ACK F3 | | | + |--------------->| | | + | INVITE F4 | | + |-------------------------------->| INVITE F5 | + | 100 F6 |--------------->| + |<--------------------------------| 180 F7 | + | 180 F8 |<---------------| + |<--------------------------------| | + | | 200 F9 | + | 200 F10 |<---------------| + |<--------------------------------| | + | ACK F11 | | + |-------------------------------->| ACK F12 | + | |--------------->| + | Both Way RTP Media | + |<================================================>| + | | BYE F13 | + | BYE F14 |<---------------| + |<--------------------------------| | + | 200 F15 | | + |-------------------------------->| 200 F16 | + | |--------------->| + | | | + + In this scenario, Alice places a call to Bob using first a Redirect + server then a Proxy Server. The INVITE message is first sent to the + Redirect Server. The Server returns a 302 Moved Temporarily response + (F2) containing a Contact header with Bob's current SIP address. + Alice then generates a new INVITE and sends to Bob via the Proxy + Server and the call proceeds normally. In this example, no SDP is + present in the INVITE, so the SDP is carried in the ACK message. + + The call is terminated when Bob sends a BYE message. + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 54] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Message Details + + F1 INVITE Alice -> Redirect Server + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bKbf9f44 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Length: 0 + + + F2 302 Moved Temporarily Redirect Proxy -> Alice + + SIP/2.0 302 Moved Temporarily + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bKbf9f44 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=53fHlqlQ2 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@chicago.example.com;transport=tcp> + Content-Length: 0 + + + F3 ACK Alice -> Redirect Server + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bKbf9f44 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=53fHlqlQ2 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F4 INVITE Alice -> Proxy 3 + + INVITE sip:bob@chicago.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + + + +Johnston, et al. Best Current Practice [Page 55] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Length: 0 + + + F5 INVITE Proxy 3 -> Bob + + INVITE sip:bob@client.chicago.example.com SIP/2.0 + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Length: 0 + + + F6 100 Trying Proxy 3 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Content-Length: 0 + + + F7 180 Ringing Bob -> Proxy 3 + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + ;received=192.0.2.233 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.chicago.example.com;transport=tcp> + Content-Length: 0 + + + + +Johnston, et al. Best Current Practice [Page 56] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + F8 180 Ringing Proxy 3 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.chicago.example.com;transport=tcp> + Content-Length: 0 + + + F9 200 OK Bob -> Proxy 3 + + SIP/2.0 200 OK + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + ;received=192.0.2.233 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.chicago.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 148 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.chicago.example.com + s=- + c=IN IP4 192.0.2.100 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F10 200 OK Proxy -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + + + +Johnston, et al. Best Current Practice [Page 57] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 INVITE + Contact: <sip:bob@client.chicago.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 148 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.chicago.example.com + s=- + c=IN IP4 192.0.2.100 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* ACK contains SDP of Alice since none present in INVITE */ + + + F11 ACK Alice -> Proxy 3 + + ACK sip:bob@client.chicago.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bq9 + Max-Forwards: 70 + Route: <sip:ss3.chicago.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 ACK + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F12 ACK Proxy 3 -> Bob + + ACK sip:bob@client.chicago.example.com SIP/2.0 + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bq9 + ;received=192.0.2.101 + Max-Forwards: 69 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + + + +Johnston, et al. Best Current Practice [Page 58] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 ACK + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /* RTP streams are established between Alice and Bob */ + + /* Bob Hangs Up with Alice. */ + + + F13 BYE Bob -> Proxy 3 + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP client.chicago.example.com:5060;branch=z9hG4bKfgaw2 + Max-Forwards: 70 + Route: <sip:ss3.chicago.example.com;lr> + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F14 BYE Proxy 3 -> Alice + + BYE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + ;received=192.0.2.100 + Via: SIP/2.0/TCP client.chicago.example.com:5060;branch=z9hG4bKfgaw2 + Max-Forwards: 69 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F15 200 OK Alice -> Proxy 3 + + SIP/2.0 200 OK + + + +Johnston, et al. Best Current Practice [Page 59] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Via: SIP/2.0/TCP ss3.chicago.example.com:5060;branch=z9hG4bK721e.1 + ;received=192.0.2.233 + Via: SIP/2.0/TCP client.chicago.example.com:5060;branch=z9hG4bKfgaw2 + ;received=192.0.2.100 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + F16 200 OK Proxy 3 -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/TCP client.chicago.example.com:5060;branch=z9hG4bKfgaw2 + ;received=192.0.2.100 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 BYE + Content-Length: 0 + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 60] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.7. Session with re-INVITE (IP Address Change) + + + Alice Proxy 2 Bob + | F1 INVITE | | + |------------------->| F2 INVITE | + | F3 100 Trying |------------------->| + |<-------------------| F4 180 Ringing | + | F5 180 Ringing |<-------------------| + |<-------------------| | + | | F6 200 OK | + | F7 200 OK |<-------------------| + |<-------------------| | + | F8 ACK | + |---------------------------------------->| + | Both Way RTP Media Established | + |<=======================================>| + | | + | Bob changes IP address | + | | + | F9 INVITE | + |<----------------------------------------| + | F10 200 OK | + |---------------------------------------->| + | F11 ACK | + |<----------------------------------------| + | New RTP Media Stream | + |<=======================================>| + | F12 BYE | + |---------------------------------------->| + | F13 200 OK | + |<----------------------------------------| + | | + + This example shows a session in which the media changes midway + through the session. When Bob's IP address changes during the + session, Bob sends a re-INVITE containing a new Contact and SDP + (version number incremented) information to A. In this flow, the + proxy does not Record-Route so is not in the SIP messaging path after + the initial exchange. + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 61] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Message Details + + F1 INVITE Alice -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F2 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + + + +Johnston, et al. Best Current Practice [Page 62] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F3 100 Trying Proxy 2 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F4 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F5 180 Ringing Proxy 2 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F6 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + + + +Johnston, et al. Best Current Practice [Page 63] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F7 200 OK Proxy 2 -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Type: application/sdp + Content-Length: 147 + + v=0 + o=bob 2890844527 2890844527 IN IP4 client.biloxi.example.com + s=- + c=IN IP4 192.0.2.201 + t=0 0 + m=audio 3456 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F8 ACK Alice -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74b7b + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + +Johnston, et al. Best Current Practice [Page 64] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + /* RTP streams are established between Alice and Bob */ + + /* Bob changes IP address and re-INVITEs Alice with new Contact and + SDP */ + + + F9 INVITE Bob -> Alice + + INVITE sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/UDP client.chicago.example.com:5060;branch=z9hG4bKlkld5l + Max-Forwards: 70 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 14 INVITE + Contact: <sip:bob@client.chicago.example.com> + Content-Type: application/sdp + Content-Length: 149 + + v=0 + o=bob 2890844527 2890844528 IN IP4 client.chicago.example.com + s=- + c=IN IP4 192.0.2.100 + t=0 0 + m=audio 47172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F10 200 OK Alice -> Bob + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.chicago.example.com:5060;branch=z9hG4bKlkld5l + ;received=192.0.2.100 + Max-Forwards: 70 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 14 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 150 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + + + +Johnston, et al. Best Current Practice [Page 65] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + m=audio 1000 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F11 ACK Bob -> Alice + + ACK sip:alice@client.atlanta.example.com SIP/2.0 + Via: SIP/2.0/UDP client.chicago.example.com:5060;branch=z9hG4bKlkldcc + Max-Forwards: 70 + From: Bob <sip:bob@biloxi.example.com>;tag=314159 + To: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 14 ACK + Content-Length: 0 + + /* New RTP stream established between Alice and Bob */ + + /* Alice hangs up with Bob */ + + + F12 BYE Alice -> Bob + + BYE sip:bob@client.chicago.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bo4 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 BYE + Content-Length: 0 + + + F13 200 OK Bob -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bo4 + ;received=192.0.2.101 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 2 BYE + Content-Length: 0 + + + + + + + + +Johnston, et al. Best Current Practice [Page 66] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.8. Unsuccessful No Answer + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| INVITE F2 | | + | 100 F3 |--------------->| INVITE F4 | + |<---------------| 100 F5 |--------------->| + | |<---------------| | + | | | 180 F6 | + | | 180 F7 |<---------------| + | 180 F8 |<---------------| | + |<---------------| | | + | CANCEL F9 | | | + |--------------->| | | + | 200 F10 | | | + |<---------------| CANCEL F11 | | + | |--------------->| | + | | 200 F12 | | + | |<---------------| | + | | | CANCEL F13 | + | | |--------------->| + | | | 200 F14 | + | | |<---------------| + | | | 487 F15 | + | | |<---------------| + | | | ACK F16 | + | | 487 F17 |--------------->| + | |<---------------| | + | | ACK F18 | | + | 487 F19 |--------------->| | + |<---------------| | | + | ACK F20 | | | + |--------------->| | | + | | | | + + In this scenario, Alice gives up on the call before Bob answers + (sends a 200 OK response). Alice sends a CANCEL (F9) since no final + response had been received from Bob. If a 200 OK to the INVITE had + crossed with the CANCEL, Alice would have sent an ACK then a BYE to + Bob in order to properly terminate the call. + + Note that the CANCEL message is acknowledged with a 200 OK on a hop + by hop basis, rather than end to end. + + + + + + + +Johnston, et al. Best Current Practice [Page 67] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="ze7k1ee88df84f1cec431ae6cbe5a359", opaque="", + uri="sip:bob@biloxi.example.com", + response="b00b416324679d7e243f55708d44be7b" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /*Client for Alice prepares to receive data on port 49172 from the + network.*/ + + + F2 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + + +Johnston, et al. Best Current Practice [Page 68] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F3 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F4 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + Max-Forwards: 68 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + +Johnston, et al. Best Current Practice [Page 69] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + + F5 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F6 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F7 180 Ringing Proxy 2 -> Proxy 1 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + + + +Johnston, et al. Best Current Practice [Page 70] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F8 180 Ringing Proxy 1 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F9 CANCEL Alice -> Proxy 1 + + CANCEL sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Route: <sip:ss1.atlanta.example.com;lr> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + F10 200 OK Proxy 1 -> Alice + + SIP/2.0 200 OK + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + + + + + + + +Johnston, et al. Best Current Practice [Page 71] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F11 CANCEL Proxy 1 -> Proxy 2 + + CANCEL sip:alice@atlanta.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + F12 200 OK Proxy 2 -> Proxy 1 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + F13 CANCEL Proxy 2 -> Bob + + CANCEL sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + F14 200 OK Bob -> Proxy 2 + + SIP/2.0 200 OK + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 CANCEL + Content-Length: 0 + + + + + +Johnston, et al. Best Current Practice [Page 72] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F15 487 Request Terminated Bob -> Proxy 2 + + SIP/2.0 487 Request Terminated + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F16 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F17 487 Request Terminated Proxy 2 -> Proxy 1 + + SIP/2.0 487 Request Terminated + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 73] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F18 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F19 487 Request Terminated Proxy 1 -> Alice + + SIP/2.0 487 Request Terminated + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + + + F20 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="ze7k1ee88df84f1cec431ae6cbe5a359", opaque="", + uri="sip:bob@biloxi.example.com", + response="b00b416324679d7e243f55708d44be7b" + CSeq: 1 ACK + Content-Length: 0 + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 74] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.9. Unsuccessful Busy + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| INVITE F2 | | + | 100 F3 |--------------->| INVITE F4 | + |<---------------| 100 F5 |--------------->| + | |<---------------| | + | | | 486 F6 | + | | |<---------------| + | | | ACK F7 | + | | 486 F8 |--------------->| + | |<---------------| | + | | ACK F9 | | + | 486 F10 |--------------->| | + |<---------------| | | + | ACK F11 | | | + |--------------->| | | + | | | | + + + In this scenario, Bob is busy and sends a 486 Busy Here response to + Alice's INVITE. Note that the non-2xx response is acknowledged on a + hop-by-hop basis instead of end-to-end. Also note that many SIP UAs + will not return a 486 response, as they have multiple line and other + features. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="dc3a5ab2530aa93112cf5904ba7d88fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="702138b27d869ac8741e10ec643d55be" + Content-Type: application/sdp + Content-Length: 151 + + + +Johnston, et al. Best Current Practice [Page 75] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /*Client for Alice prepares to receive data on port 49172 from the + network.*/ + + + F2 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F3 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + +Johnston, et al. Best Current Practice [Page 76] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F4 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com;transport=tcp> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F5 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F6 486 Busy Here Bob -> Proxy 2 + + SIP/2.0 486 Busy Here + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + + + +Johnston, et al. Best Current Practice [Page 77] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F7 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F8 486 Busy Here Proxy 2 -> Proxy 1 + + SIP/2.0 486 Busy Here + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F9 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + + + +Johnston, et al. Best Current Practice [Page 78] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F10 486 Busy Here Proxy 1 -> Alice + + SIP/2.0 486 Busy Here + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F11 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/TCP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="dc3a5ab2530aa93112cf5904ba7d88fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="702138b27d869ac8741e10ec643d55be" + Content-Length: 0 + + + + + + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 79] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.10. Unsuccessful No Response from User Agent + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| INVITE F2 | | + | 100 F3 |--------------->| INVITE F4 | + |<---------------| 100 F5 |--------------->| + | |<---------------| INVITE F6 | + | | |--------------->| + | | | INVITE F7 | + | | |--------------->| + | | | INVITE F8 | + | | |--------------->| + | | | INVITE F9 | + | | |--------------->| + | | | INVITE F10 | + | | |--------------->| + | | | INVITE F11 | + | | 480 F12 |--------------->| + | |<---------------| | + | | ACK F13 | | + | 480 F14 |--------------->| | + |<---------------| | | + | ACK F15 | | | + |--------------->| | | + | | | | + + In this example, there is no response from Bob to Alice's INVITE + messages being re-transmitted by Proxy 2. After the sixth + re-transmission, Proxy 2 gives up and sends a 480 No Response to + Alice. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + + + +Johnston, et al. Best Current Practice [Page 80] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + nonce="cf5904ba7d8dc3a5ab2530aa931128fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="7afc04be7961f053c24f80e7dbaf888f" + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /*Client for Alice prepares to receive data on port 49172 from the + network.*/ + + + F2 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F3 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + + + +Johnston, et al. Best Current Practice [Page 81] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F4 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F5 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + + +Johnston, et al. Best Current Practice [Page 82] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + + F6 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + + F7 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + + F8 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + + F9 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + + F10 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + + F11 INVITE Proxy 2 -> Bob + + Resend of Message F4 + + /* Proxy 2 gives up */ + + + F12 480 No Response Proxy 2 -> Proxy 1 + + SIP/2.0 480 No Response + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + + + + +Johnston, et al. Best Current Practice [Page 83] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F13 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F14 480 No Response Proxy 1 -> Alice + + SIP/2.0 480 No Response + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F15 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="cf5904ba7d8dc3a5ab2530aa931128fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="7afc04be7961f053c24f80e7dbaf888f" + Content-Length: 0 + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 84] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +3.11. Unsuccessful Temporarily Unavailable + + Alice Proxy 1 Proxy 2 Bob + | | | | + | INVITE F1 | | | + |--------------->| INVITE F2 | | + | 100 F3 |--------------->| INVITE F4 | + |<---------------| 100 F5 |--------------->| + | |<---------------| 180 F6 | + | | 180 F7 |<---------------| + | 180 F8 |<---------------| | + |<---------------| | 480 F9 | + | | |<---------------| + | | | ACK F10 | + | | 480 F11 |--------------->| + | |<---------------| | + | | ACK F12 | | + | 480 F13 |--------------->| | + |<---------------| | | + | ACK F14 | | | + |--------------->| | | + | | | | + + + In this scenario, Bob initially sends a 180 Ringing response to + Alice, indicating that alerting is taking place. However, then a + 480 Unavailable is then sent to Alice. This response is + acknowledged then proxied back to Alice. + + Message Details + + F1 INVITE Alice -> Proxy 1 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="aa9311cf5904ba7d8dc3a5ab253028fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="59a46a91bf1646562a4d486c84b399db" + Content-Type: application/sdp + + + +Johnston, et al. Best Current Practice [Page 85] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + /*Client for Alice prepares to receive data on port 49172 from the + network.*/ + + + F2 INVITE Proxy 1 -> Proxy 2 + + INVITE sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 69 + Record-Route: <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F3 100 Trying Proxy 1 -> Alice + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + + + +Johnston, et al. Best Current Practice [Page 86] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Content-Length: 0 + + + F4 INVITE Proxy 2 -> Bob + + INVITE sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Max-Forwards: 68 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:alice@client.atlanta.example.com> + Content-Type: application/sdp + Content-Length: 151 + + v=0 + o=alice 2890844526 2890844526 IN IP4 client.atlanta.example.com + s=- + c=IN IP4 192.0.2.101 + t=0 0 + m=audio 49172 RTP/AVP 0 + a=rtpmap:0 PCMU/8000 + + + F5 100 Trying Proxy 2 -> Proxy 1 + + SIP/2.0 100 Trying + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com> + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + + + + + + +Johnston, et al. Best Current Practice [Page 87] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F6 180 Ringing Bob -> Proxy 2 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F7 180 Ringing Proxy 2 -> Proxy 1 + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + Content-Length: 0 + + + F8 180 Ringing Proxy 1 -> Alice + + SIP/2.0 180 Ringing + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + Record-Route: <sip:ss2.biloxi.example.com;lr>, + <sip:ss1.atlanta.example.com;lr> + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Contact: <sip:bob@client.biloxi.example.com> + + + +Johnston, et al. Best Current Practice [Page 88] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + Content-Length: 0 + + + F9 480 Temporarily Unavailable Bob -> Proxy 2 + + SIP/2.0 480 Temporarily Unavailable + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + ;received=192.0.2.222 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F10 ACK Proxy 2 -> Bob + + ACK sip:bob@client.biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss2.biloxi.example.com:5060;branch=z9hG4bK721e4.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F11 480 Temporarily Unavailable Proxy 2 -> Proxy 1 + + SIP/2.0 480 Temporarily Unavailable + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + ;received=192.0.2.111 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + + + + + + +Johnston, et al. Best Current Practice [Page 89] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + F12 ACK Proxy 1 -> Proxy 2 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP ss1.atlanta.example.com:5060;branch=z9hG4bK2d4790.1 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 ACK + Content-Length: 0 + + + F13 480 Temporarily Unavailable Proxy 1 -> Alice + + SIP/2.0 480 Temporarily Unavailable + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + ;received=192.0.2.101 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + CSeq: 1 INVITE + Content-Length: 0 + + + F14 ACK Alice -> Proxy 1 + + ACK sip:bob@biloxi.example.com SIP/2.0 + Via: SIP/2.0/UDP client.atlanta.example.com:5060;branch=z9hG4bK74bf9 + Max-Forwards: 70 + From: Alice <sip:alice@atlanta.example.com>;tag=9fxced76sl + To: Bob <sip:bob@biloxi.example.com>;tag=314159 + Call-ID: 2xTb9vxSit55XU7p8@atlanta.example.com + Proxy-Authorization: Digest username="alice", + realm="atlanta.example.com", + nonce="aa9311cf5904ba7d8dc3a5ab253028fa", opaque="", + uri="sip:bob@biloxi.example.com", + response="59a46a91bf1646562a4d486c84b399db" + CSeq: 1 ACK + Content-Length: 0 + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 90] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +4. Security Considerations + + Since this document contains examples of SIP session establishment, + the security considerations in RFC 3261 [1] apply. RFC 3261 + describes the basic threats including registration hijacking, server + impersonation, message body tampering, session modifying or teardown, + and denial of service and amplification attacks. The use of HTTP + Digest as shown in this document provides one-way authentication and + protection against replay attacks. TLS transport is used in + registration scenarios due to the lack of integrity protection in + HTTP Digest and the danger of registration hijacking without it, as + described in RFC 3261 [1]. A full discussion of the weaknesses of + HTTP Digest is provided in RFC 3261 [1]. The use of TLS and the + Secure SIP (sips) URI scheme provides a better level of security + including two-way authentication. S/MIME can provide end-to-end + confidentiality and integrity protection of message bodies, as + described in RFC 3261. + +5. References + +5.1. Normative References + + [1] Rosenberg, J., Schulzrinne, H., Camarillo, G., Johnston, A., + Peterson, J., Sparks, R., Handley, M. and E. Schooler, "SIP: + Session Initiation Protocol", RFC 3261, June 2002. + + [2] Rosenberg, J. and H. Schulzrinne, "An Offer/Answer Model with + SDP", RFC 3264, April 2002. + + [3] Franks, J., Hallam-Baker, P., Hostetler, J., Lawrence, S., Leach, + P., Luotonen, A. and L. Stewart, "HTTP authentication: Basic and + Digest Access Authentication", RFC 2617, June 1999. + + [4] Bradner, S., "Key words for use in RFCs to Indicate Requirement + Levels", BCP 14, RFC 2119, March 1997. + +5.2. Informative References + + [5] Johnston, A., Donovan, S., Sparks, R., Cunningham, C. and K. + Summers, "Session Initiation Protocol (SIP) Public Switched + Telephone Network (PSTN) Call Flows", BCP 76, RFC 3666, December + 2003. + +6. Intellectual Property Statement + + The IETF takes no position regarding the validity or scope of any + intellectual property or other rights that might be claimed to + pertain to the implementation or use of the technology described in + + + +Johnston, et al. Best Current Practice [Page 91] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + + this document or the extent to which any license under such rights + might or might not be available; neither does it represent that it + has made any effort to identify any such rights. Information on the + IETF's procedures with respect to rights in standards-track and + standards-related documentation can be found in BCP-11. Copies of + claims of rights made available for publication and any assurances of + licenses to be made available, or the result of an attempt made to + obtain a general license or permission for the use of such + proprietary rights by implementors or users of this specification can + be obtained from the IETF Secretariat. + + The IETF invites any interested party to bring to its attention any + copyrights, patents or patent applications, or other proprietary + rights which may cover technology that may be required to practice + this standard. Please address the information to the IETF Executive + Director. + +7. Acknowledgments + + This document is has been a group effort by the SIP and SIPPING WGs. + The authors wish to thank everyone who has read, reviewed, commented, + or made suggestions to improve this document. + + Thanks to Rohan Mahy, Adam Roach, Gonzalo Camarillo, Cullen Jennings, + and Tom Taylor for their detailed comments during the final review. + Thanks to Dean Willis for his early contributions to the development + of this document. + + The authors wish to thank Kundan Singh for performing parser + validation of messages. + + The authors wish to thank the following individuals for their + participation in the review of this call flows document: Aseem + Agarwal, Rafi Assadi, Ben Campbell, Sunitha Kumar, Jon Peterson, Marc + Petit-Huguenin, Vidhi Rastogi, and Bodgey Yin Shaohua. + + The authors also wish to thank the following individuals for their + assistance: Jean-Francois Mule, Hemant Agrawal, Henry Sinnreich, + David Devanatham, Joe Pizzimenti, Matt Cannon, John Hearty, the whole + MCI WorldCom IPOP Design team, Scott Orton, Greg Osterhout, Pat + Sollee, Doug Weisenberg, Danny Mistry, Steve McKinnon, and Denise + Ingram, Denise Caballero, Tom Redman, Ilya Slain, Pat Sollee, John + Truetken, and others from MCI WorldCom, 3Com, Cisco, Lucent and + Nortel. + + + + + + + +Johnston, et al. Best Current Practice [Page 92] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +8. Authors' Addresses + + All listed authors actively contributed large amounts of text to this + document. + + Alan Johnston + MCI + 100 South 4th Street + St. Louis, MO 63102 + USA + + EMail: alan.johnston@mci.com + + Steve Donovan + dynamicsoft, Inc. + 5100 Tennyson Parkway + Suite 1200 + Plano, Texas 75024 + USA + + EMail: sdonovan@dynamicsoft.com + + Robert Sparks + dynamicsoft, Inc. + 5100 Tennyson Parkway + Suite 1200 + Plano, Texas 75024 + USA + + EMail: rsparks@dynamicsoft.com + + Chris Cunningham + dynamicsoft, Inc. + 5100 Tennyson Parkway + Suite 1200 + Plano, Texas 75024 + USA + + EMail: ccunningham@dynamicsoft.com + + Kevin Summers + Sonus + 1701 North Collins Blvd, Suite 3000 + Richardson, TX 75080 + USA + + EMail: kevin.summers@sonusnet.com + + + + +Johnston, et al. Best Current Practice [Page 93] + +RFC 3665 SIP Basic Call Flow Examples December 2003 + + +9. Full Copyright Statement + + Copyright (C) The Internet Society (2003). All Rights Reserved. + + This document and translations of it may be copied and furnished to + others, and derivative works that comment on or otherwise explain it + or assist in its implementation may be prepared, copied, published + and distributed, in whole or in part, without restriction of any + kind, provided that the above copyright notice and this paragraph are + included on all such copies and derivative works. However, this + document itself may not be modified in any way, such as by removing + the copyright notice or references to the Internet Society or other + Internet organizations, except as needed for the purpose of + developing Internet standards in which case the procedures for + copyrights defined in the Internet Standards process must be + followed, or as required to translate it into languages other than + English. + + The limited permissions granted above are perpetual and will not be + revoked by the Internet Society or its successors or assignees. + + This document and the information contained herein is provided on an + "AS IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING + TASK FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING + BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION + HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF + MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE. + +Acknowledgement + + Funding for the RFC Editor function is currently provided by the + Internet Society. + + + + + + + + + + + + + + + + + + + +Johnston, et al. Best Current Practice [Page 94] + |