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diff --git a/doc/rfc/rfc1552.txt b/doc/rfc/rfc1552.txt new file mode 100644 index 0000000..ca5d1e3 --- /dev/null +++ b/doc/rfc/rfc1552.txt @@ -0,0 +1,899 @@ + + + + + + +Network Working Group W. Simpson +Request for Comments: 1552 Daydreamer +Category: Standards Track December 1993 + + + The PPP Internetwork Packet Exchange Control Protocol (IPXCP) + + +Status of this Memo + + This document specifies an Internet standards track protocol for the + Internet community, and requests discussion and suggestions for + improvements. Please refer to the current edition of the "Internet + Official Protocol Standards" (STD 1) for the standardization state + and status of this protocol. Distribution of this memo is unlimited. + +Abstract + + The Point-to-Point Protocol (PPP) [1] provides a method for + transmitting multi-protocol datagrams over point-to-point links. PPP + defines an extensible Link Control Protocol, and proposes a family of + Network Control Protocols for establishing and configuring different + network-layer protocols. + + The IPX protocol was originally used in Novell's NetWare products + [3], and is now supported by numerous other vendors. This document + defines the Network Control Protocol for establishing and configuring + the IPX protocol over PPP. + + This memo is the product of the Point-to-Point Protocol Working Group + of the IETF. Comments should be submitted to the ietf- + ppp@ucdavis.edu mailing list. + + + + + + + + + + + + + + + + + + + +Simpson [Page 1] + +RFC 1552 PPP IPXCP December 1993 + + +Table of Contents + + 1. Introduction ...................................................2 + 1.1 Specification of Requirements ..................................3 + 1.2 Terminology ....................................................3 + 2. A PPP Network Control Protocol for IPX .........................4 + 2.1 Sending IPX Datagrams ..........................................5 + 2.2 IPX-WAN protocol ...............................................5 + 2.3 Desired Parameters .............................................5 + 2.4 Co-existence with IPX-WAN ......................................6 + 3. IPXCP Configuration Options ....................................6 + 3.1 IPX-Network-Number .............................................7 + 3.2 IPX-Node-Number ................................................8 + 3.3 IPX-Compression-Protocol .......................................9 + 3.4 IPX-Routing-Protocol ...........................................11 + 3.5 IPX-Router-Name ................................................12 + 3.6 IPX-Configuration-Complete .....................................13 + APPENDIX A. Link Delay and Throughput ..............................14 + SECURITY CONSIDERATIONS ............................................14 + REFERENCES .........................................................15 + ACKNOWLEDGEMENTS ...................................................15 + CHAIR'S ADDRESS ....................................................15 + AUTHOR'S ADDRESS ...................................................16 + +1. Introduction + + PPP has three main components: + + 1. A method for encapsulating multi-protocol datagrams. + + 2. A Link Control Protocol (LCP) for establishing, configuring, + and testing the data-link connection. + + 3. A family of Network Control Protocols for establishing and + configuring different network-layer protocols. + + In order to establish communications over a point-to-point link, each + end of the PPP link must first send LCP packets to configure and test + the data link. After the link has been established and optional + facilities have been negotiated as needed by the LCP, PPP must send + IPXCP packets to choose and configure the IPX network-layer protocol. + Once IPXCP has reached the Opened state, IPX datagrams can be sent + over the link. + + The link will remain configured for communications until explicit LCP + or IPXCP packets close the link down, or until some external event + occurs (an inactivity timer expires or network administrator + intervention). + + + +Simpson [Page 2] + +RFC 1552 PPP IPXCP December 1993 + + +1.1 Specification of Requirements + + In this document, several words are used to signify the requirements + of the specification. These words are often capitalized. + + MUST + + This word, or the adjective "required", means that the definition + is an absolute requirement of the specification. + + MUST NOT + + This phrase means that the definition is an absolute prohibition + of the specification. + + SHOULD + + This word, or the adjective "recommended", means that there may + exist valid reasons in particular circumstances to ignore this + item, but the full implications should be understood and carefully + weighed before choosing a different course. + + MAY + + This word, or the adjective "optional", means that this item is + one of an allowed set of alternatives. An implementation which + does not include this option MUST be prepared to interoperate with + another implementation which does include the option. + + +1.2 Terminology + + This document frequently uses the following terms: + + peer + + The other end of the point-to-point link. + + silently discard + + This means the implementation discards the packet without further + processing. The implementation SHOULD provide the capability of + logging the error, including the contents of the silently + discarded packet, and SHOULD record the event in a statistics + counter. + + + + + + +Simpson [Page 3] + +RFC 1552 PPP IPXCP December 1993 + + + end-system + + A user's machine. It only sends packets to servers and other + end-systems. It doesn't pass any packets through itself. + + router + + Allows packets to pass through, usually from one ethernet segment + to another. Sometimes these are called "intermediate-systems". + + half-router + + Two normal routers, with an unnumbered link between them. Each + looks like a router to the local users, but Netware doesn't + understand unnumbered links, so each router is made to look like + they both are a single machine. + +2. A PPP Network Control Protocol for IPX + + The IPX Control Protocol (IPXCP) is responsible for configuring, + enabling, and disabling the IPX protocol modules on both ends of the + point-to-point link. IPXCP uses the same packet exchange mechanism + as the Link Control Protocol. IPXCP packets may not be exchanged + until PPP has reached the Network-Layer Protocol phase. IPXCP + packets received before this phase is reached should be silently + discarded. + + The IPX Control Protocol is exactly the same as the Link Control + Protocol [1] with the following exceptions: + + Frame Modifications + + The packet may utilize any modifications to the basic frame format + which have been negotiated during the Link Establishment phase. + + Data Link Layer Protocol Field + + Exactly one IPXCP packet is encapsulated in the Information field + of a PPP Data Link Layer frame where the Protocol field indicates + type hex 802B (IPX Control Protocol). + + Code field + + Only Codes 1 through 7 (Configure-Request, Configure-Ack, + Configure-Nak, Configure-Reject, Terminate-Request, Terminate-Ack + and Code-Reject) are used. Other Codes should be treated as + unrecognized and should result in Code-Rejects. + + + + +Simpson [Page 4] + +RFC 1552 PPP IPXCP December 1993 + + + Timeouts + + IPXCP packets may not be exchanged until PPP has reached the + Network-Layer Protocol phase. An implementation should be + prepared to wait for Authentication and Link Quality Determination + to finish before timing out waiting for a Configure-Ack or other + response. It is suggested that an implementation give up only + after user intervention or a configurable amount of time. + + Configuration Option Types + + IPXCP has a distinct set of Configuration Options. + +2.1 Sending IPX Datagrams + + Before any IPX packets may be communicated, PPP must reach the + Network-Layer Protocol phase, and the IPX Control Protocol must reach + the Opened state. + + Exactly one IPX packet is encapsulated in the Information field of a + PPP Data Link Layer frame where the Protocol field indicates type hex + 002B (IPX datagram). + + The maximum length of an IPX datagram transmitted over a PPP link is + the same as the maximum length of the Information field of a PPP data + link layer frame. Since there is no standard method for fragmenting + and reassembling IPX datagrams, PPP links supporting IPX MUST allow + at least 576 octets in the information field of a data link layer + frame. + +2.2 IPX-WAN protocol + + A Novell specification called IPX-WAN [4] is intended to provide + mechanisms similar to IPXCP negotiation over wide area links. As + viewed by PPP, IPX-WAN is a part of IPX, and IPX-WAN packets are + indistinguishable from other IPX packets. + + Currently, Novell has implemented IPXCP without any Configuration + Options, and requires successful IPX-WAN completion, even when all + required parameters have been hand configured. This makes it + impossible for the current Novell products to interoperate with other + IPXCP implementations which do not already include support for IPX- + WAN. + +2.3 Desired Parameters + + To resolve the possible conflict between the two configuration + methods, this specification defines the concept of "Desired + + + +Simpson [Page 5] + +RFC 1552 PPP IPXCP December 1993 + + + Parameters". Where applicable, each Configuration Option indicates + the environment where the parameter which is negotiated MAY be + required by the implementation for proper operation. + + This determination is highly implementation dependent. For example, + a particular implementation might require that all links have + addresses, while another implementation might not need such + addresses. The configuration negotiation is intended to discover + that this pair of implementations will never converge. + +2.4 Co-existence with IPX-WAN + + An IPXCP implementation which includes support for IPX-WAN SHOULD + always reach Opened state, even when unable to negotiate some + "Desired Parameter", and when no Configuration Options are + successfully negotiated. This allows IPX-WAN the opportunity to + finish the negotiation. + + If an implementation does not include support for IPX-WAN, it SHOULD + NOT reach Opened state when unable to negotiate some "Desired + Parameter". + + IPX-WAN uses a "Timer Request" packet to set up the link. These MUST + NOT be sent until IPXCP has Opened the link. + + An implementation which provides both IPX-WAN and IPXCP Configuration + Options capability SHOULD only send a Timer Request packet when a + Timer Request packet is received, or upon failure to successfully + negotiate a "Desired Parameter". + + If unable to complete IPX-WAN setup when a "Desired Parameter" is + unknown, by default IPXCP SHOULD terminate the link. + + However, some implementations might be capable of operating without + all indicated "Desired Parameters", in which case the termination + MUST be configurable. + +3. IPXCP Configuration Options + + IPXCP Configuration Options allow modifications to the standard + characteristics of the network-layer protocol to be negotiated. If a + Configuration Option is not included in a Configure-Request packet, + the default value for that Configuration Option is assumed. + + IPXCP uses the same Configuration Option format defined for LCP [1], + with a separate set of Options. + + Up-to-date values of the IPXCP Option Type field are specified in the + + + +Simpson [Page 6] + +RFC 1552 PPP IPXCP December 1993 + + + most recent "Assigned Numbers" RFC [2]. Current values are assigned + as follows: + + 1 IPX-Network-Number + 2 IPX-Node-Number + 3 IPX-Compression-Protocol + 4 IPX-Routing-Protocol + 5 IPX-Router-Name + 6 IPX-Configuration-Complete + +3.1 IPX-Network-Number + + Description + + This Configuration Option provides a way to negotiate the IPX + network number to be used for the link. This allows an + implementation to learn the network number, or to ensure agreement + on the network number. + + The network number MUST be unique within the routing domain, or + zero to indicate that it is not used for routing. + + The sender of the Configure-Request states which network number is + desired. A network number specified as zero in a Configure- + Request shall be interpreted as requesting the peer to specify + another value in a Configure-Nak. A network number specified as + zero in a Configure-Ack shall be interpreted as agreement that no + value exists. + + Both ends of the link MUST have the same network number. When a + Configure-Request is received which has a lower network number + than locally configured, a Configure-Nak MUST be returned with the + highest network number. + + When the peer did not provide the option in its Configure-Request, + the option SHOULD NOT be appended to a Configure-Nak. + + By default, no network number is assigned to the link (the network + number is zero). There is no need for a network number if the + interface is not used by a routing protocol. + + This is a Desired Parameter when the implementation is operating + as a router. It MUST be negotiated if the network number is non- + zero, and has been derived from another interface. + + Any IPX-WAN packets received MUST supercede information negotiated + in this option. + + + + +Simpson [Page 7] + +RFC 1552 PPP IPXCP December 1993 + + + A summary of the IPX-Network-Number Configuration Option format is + shown below. The fields are transmitted from left to right. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | IPX-Network-Number | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | IPX-Network-Number (cont.) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + + 1 + + Length + + 6 + + IPX-Network-Number + + The four octet IPX-Network-Number is the desired local IPX network + number of the sender of the Configure-Request. This number may be + zero, which is interpreted as being a local network of unknown + number that is not used by the routing protocol. + +3.2 IPX-Node-Number + + Description + + This Configuration Option provides a way to negotiate the IPX node + number to be used for the local end of the link. This allows an + implementation to learn its node number, or to inform the peer of + its node number. + + The node number MUST be unique for the network number. + + The sender of the Configure-Request states which node number is + desired. A node number specified as zero in a Configure-Request + shall be interpreted as requesting the peer to specify another + value in a Configure-Nak. A node number specified as zero in a + Configure-Ack shall be interpreted as agreement that no value + exists. + + If negotiation about the peer node number is required, and the + peer did not provide the option in its Configure-Request, the + option can be appended to a Configure-Nak. The value of the node + number given MUST be acceptable as the peer IPX-Node-Number, or + + + +Simpson [Page 8] + +RFC 1552 PPP IPXCP December 1993 + + + indicate with a zero value that the peer provide the information. + + By default, no node number is assigned to the link (the node + number is zero). There is no need for a node number if the + interface is not used by a routing protocol. + + This is a Desired Parameter when the implementation is operating + as an end-system. However, when the node number has been + statically configured, this option SHOULD NOT be negotiated unless + requested by the peer. + + Any IPX-WAN packets received MUST supercede information negotiated + in this option. + + A summary of the IPX-Node-Number Configuration Option format is + shown below. The fields are transmitted from left to right. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | IPX-Node-Number | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | IPX-Node-Number (cont.) | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + + 2 + + Length + + 8 + + IPX-Node-Number + + The six octet IPX-Node-Number is the desired local IPX node number + of the sender of the Configure-Request. + +3.3 IPX-Compression-Protocol + + Description + + This Configuration Option provides a way to negotiate the use of a + specific compression protocol. By default, compression is not + enabled. + + The sender of this Configuration Option indicates that it can + receive packets with the specified compression technique. A + + + +Simpson [Page 9] + +RFC 1552 PPP IPXCP December 1993 + + + Configure-Ack MAY obligate the peer to send such packets, + depending on the protocol negotiated. + + Information negotiated in this option MUST supercede any IPX-WAN + packets received, since IPX-WAN packets could be affected by the + compression technique. + + A summary of the IPX-Compression-Protocol Configuration Option + format is shown below. The fields are transmitted from left to + right. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | IPX-Compression-Protocol | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Data ... + +-+-+-+-+ + + Type + + 3 + + Length + + >= 4 + + IPX-Compression-Protocol + + The IPX-Compression-Protocol field is two octets and indicates the + compression protocol desired. Odd values for this field are always + the same as the PPP Data Link Layer Protocol field values for that + same compression protocol. Even values are used when the compression + protocol is interleaved with IPX packets. + + Up-to-date values of the IPX-Compression-Protocol field are specified + in the most recent "Assigned Numbers" RFC [2]. Current values are + assigned as follows: + + Value (in hex) Protocol + + 0002 Telebit Compressed IPX + 0235 Shiva Compressed NCP/IPX + + Data + + The Data field is zero or more octets and contains additional data + as determined by the particular compression protocol. + + + +Simpson [Page 10] + +RFC 1552 PPP IPXCP December 1993 + + +3.4 IPX-Routing-Protocol + + Description + + This Configuration Option provides a way to negotiate the use of a + specific routing protocol (or no routing protocol, if desired). + The sender of this option is specifying that it wishes to receive + information of the specified routing protocol. Multiple protocols + MAY be requested by sending multiple IPX-Routing-Protocol + Configuration Options. The "no routing protocol required" value + is mutually exclusive with other values. + + By default, Novell's combination of Routing Information Protocol + (RIP) and Server Advertising Protocol (SAP) is expected. + + This is a Desired Parameter when the implementation is operating + as an end-system, to indicate that no routing protocol is + necessary. + + Any IPX-WAN packets received MAY add to information negotiated in + this option. + + A summary of the IPX-Routing-Protocol Configuration Option format is + shown below. The fields are transmitted from left to right. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | IPX-Routing-Protocol | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Data ... + +-+-+-+-+ + + Type + + 4 + + Length + + >= 4 + + IPX-Routing-Protocol + + The IPX-Routing-Protocol field is two octets and indicates the + type of Routing-Protocol desired. This two octet quantity is sent + most significant octet first. + + Up-to-date values of the IPX-Routing-Protocol field are specified + + + +Simpson [Page 11] + +RFC 1552 PPP IPXCP December 1993 + + + in the most recent "Assigned Numbers" RFC [2]. Current values are + assigned as follows: + + Value Protocol + + 0 No routing protocol required + 1 RESERVED + 2 Novell RIP/SAP required + 4 Novell NLSP required + + + Data + + The Data field is zero or more octets and contains additional data + as determined by the routing protocol indicated in the Routing- + Protocol field. + +3.5 IPX-Router-Name + + Description + + This Configuration Option provides a way to convey information + about the IPX server name. + + The nature of this option is advisory only. It is provided as a + means of improving the end system's ability to provide a simple + user interface. This option MUST NOT be included in a Configure- + Nak. + + A summary of the IPX-Router-Name Option format is shown below. The + fields are transmitted from left to right. + + 0 1 2 3 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | Name... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + + 5 + + Length + + >= 3 + + + + + + +Simpson [Page 12] + +RFC 1552 PPP IPXCP December 1993 + + + Name + + This field contains the name of the IPX entity on this end of the + link. The symbolic name should be between 1 and 47 ASCII + characters in length, containing the characters 'A' through 'Z', + underscore (_), hyphen (-) and "at" sign (@). The length of the + name is bounded by the option length. + + On reception, the name SHOULD be padded to 48 characters using the + NUL character. Those readers familiar with NetWare 3.x servers + will realize that this is equivalent to the file server name. + +3.6 IPX-Configuration-Complete + + Description + + This Configuration Option provides a way to indicate that all + implementation-dependent Desired Parameters are satisfied. It is + provided as a means of detecting when convergence will occur in a + heterogeneous environment. + + This option SHOULD be included in a Configure-Request when the + combination of statically configured parameters and offered + Configuration Options will result in successful configuration. + + The nature of this option is advisory only. This option MUST NOT + be included in a Configure-Nak. + + Implementation Note: An implementation which does not support + IPX-WAN can immediately detect that link setup will not be + successful when a Desired Parameter is unknown, if this option is + not present in the peer's Configure-Request or is Rejected by the + peer. This avoids timeout delays. + + An implementation which supports IPX-WAN may improve link setup + time by skipping IPX-WAN entirely when this option has been Ack'd + in both directions. + + However, it is perfectly acceptable to complete configuration + without including this option. An implementation which includes + the entire panoply of configuration options and IPX- WAN SHOULD + interoperate with an implementation which does not support IPX-WAN + nor any configuration options (including this one), as long as the + Desired Parameters are satisfied by default or hand configuration. + + A summary of the IPX-Configuration-Complete Option format is shown + below. The fields are transmitted from left to right. + + + + +Simpson [Page 13] + +RFC 1552 PPP IPXCP December 1993 + + + 0 1 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | Type | Length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + Type + + 6 + + Length + + 2 + +APPENDIX A. Link Delay and Throughput + + There has been some concern over correctly estimating the link delay + (in 55 millisecond ticks) used by Novell routing protocols. + + IPX-WAN uses its Timer Request and Reply for this purpose. The + measured delay is multiplied by a factor of 6, because the + measurement is done during initialization of the link, and does not + reflect actual loading. + + The delay is better measured using the PPP LCP Echo facility, by + inserting a timestamp in the data part of the Request, and comparing + it with the same timer when the reply returns. This method could be + used to periodically re-evaluate the actual round trip delay as link + and system loads change. The echo packet size SHOULD be 576, to + match the default IPX packet size. + + In the absence of such dynamic measurements, empirical evidence has + shown the following to be sufficient: + + 2,400 bps 134 ticks + 14,400 bps 21 ticks + 57,600 bps 5 ticks + > 1 Mbps 1 tick + +Security Considerations + + Security issues are not discussed in this memo. + + + + + + + + + +Simpson [Page 14] + +RFC 1552 PPP IPXCP December 1993 + + +References + + [1] Simpson, W., "The Point-to-Point Protocol (PPP)", RFC 1548, + Daydreamer, December 1993. + + [2] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2, RFC 1340, + USC/Information Sciences Institute, July 1992. + + [3] Novell Inc., "NetWare System Interface Technical Overview", + Novell Part Number 883-001143-001. + + [4] Allen, M., "Novell IPX Over Various WAN Media", RFC 1551, + Novell Inc., December 1993. + + [5] Mathu, S., and M. Lewis, "Compressing IPX Headers Over WAN + Media (CIPX)", RFC 1553, Telebit Corporation, December 1993. + +Acknowledgments + + Some of the text in this document is taken from previous documents + produced by the Point-to-Point Protocol Working Group of the Internet + Engineering Task Force (IETF). + + This document is derivative of drafts written by the following + people. Many thanks for their work, and for taking an initial stab + at the protocol: + + Michael Allen (mallen@novell.com) + Dave McCool (dave@shiva.com) + Robert D Vincent (bert@shiva.com) + Marty Del Vecchio (marty@shiva.com) + +Chair's Address + + The working group can be contacted via the current chair: + + Fred Baker + Advanced Computer Communications + 315 Bollay Drive + Santa Barbara, California, 93111 + + EMail: fbaker@acc.com + + + + + + + + + +Simpson [Page 15] + +RFC 1552 PPP IPXCP December 1993 + + +Author's Address + + Questions about this memo can also be directed to: + + William Allen Simpson + Daydreamer + Computer Systems Consulting Services + P O Box 6205 + East Lansing, MI 48826-6205 + + EMail: Bill.Simpson@um.cc.umich.edu + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +Simpson [Page 16] +
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