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diff --git a/doc/rfc/rfc5417.txt b/doc/rfc/rfc5417.txt new file mode 100644 index 0000000..fdb7e52 --- /dev/null +++ b/doc/rfc/rfc5417.txt @@ -0,0 +1,339 @@ + + + + + + +Network Working Group P. Calhoun +Request for Comments: 5417 Cisco Systems, Inc. +Category: Standards Track March 2009 + + + Control And Provisioning of Wireless Access Points (CAPWAP) + Access Controller DHCP Option + +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. + +Copyright Notice + + Copyright (c) 2009 IETF Trust and the persons identified as the + document authors. All rights reserved. + + This document is subject to BCP 78 and the IETF Trust's Legal + Provisions Relating to IETF Documents in effect on the date of + publication of this document (http://trustee.ietf.org/license-info). + Please review these documents carefully, as they describe your rights + and restrictions with respect to this document. + + This document may contain material from IETF Documents or IETF + Contributions published or made publicly available before November + 10, 2008. The person(s) controlling the copyright in some of this + material may not have granted the IETF Trust the right to allow + modifications of such material outside the IETF Standards Process. + Without obtaining an adequate license from the person(s) controlling + the copyright in such materials, this document may not be modified + outside the IETF Standards Process, and derivative works of it may + not be created outside the IETF Standards Process, except to format + it for publication as an RFC or to translate it into languages other + than English. + +Abstract + + The Control And Provisioning of Wireless Access Points Protocol + allows a Wireless Termination Point to use DHCP to discover the + Access Controllers to which it is to connect. This document + describes the DHCP options to be used by the CAPWAP Protocol. + + + + + + +Calhoun Standards Track [Page 1] + +RFC 5417 CAPWAP AC DHCP Option March 2009 + + +Table of Contents + + 1. Introduction ....................................................2 + 1.1. Conventions Used in This Document ..........................2 + 1.2. Terminology ................................................2 + 2. CAPWAP AC DHCPv4 Option .........................................2 + 3. CAPWAP AC DHCPv6 Option .........................................3 + 4. IANA Considerations .............................................5 + 5. Security Considerations .........................................5 + 6. Acknowledgments .................................................5 + 7. References ......................................................5 + 7.1. Normative References .......................................5 + 7.2. Informative References .....................................6 + +1. Introduction + + The Control And Provisioning of Wireless Access Points Protocol + (CAPWAP) [RFC5415] allows a Wireless Termination Point (WTP) to use + DHCP to discover the Access Controllers (AC) to which it is to + connect. + + Prior to the CAPWAP Discovery process, the WTP may use one of many + methods to identify the proper AC with which to establish a CAPWAP + connection. One of these methods is through the DHCP protocol. This + is done through the CAPWAP AC DHCPv4 or CAPWAP AC DHCPv6 Option. + +1.1. Conventions Used in This Document + + 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 RFC 2119 [RFC2119]. + +1.2. Terminology + + This document uses terminology defined in [RFC3753], [RFC2131], + [RFC3315], and [RFC5415]. + +2. CAPWAP AC DHCPv4 Option + + This section defines a DHCPv4 option that carries a list of 32-bit + (binary) IPv4 addresses indicating one or more CAPWAP ACs available + to the WTP. + + + + + + + + + +Calhoun Standards Track [Page 2] + +RFC 5417 CAPWAP AC DHCP Option March 2009 + + + The DHCPv4 option for CAPWAP has the format shown in the following + figure: + + 0 1 + 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | option-code | option-length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + AC IPv4 Address + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | ... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + option-code: OPTION_CAPWAP_AC_V4 (138) + + option-length: Length of the 'options' field in octets; MUST be a + multiple of four (4). + + AC IPv4 Address: IPv4 address of a CAPWAP AC that the WTP may use. + The ACs are listed in the order of preference for use by the WTP. + + A DHCPv4 client, acting on behalf of a CAPWAP WTP, MUST request the + CAPWAP AC DHCPv4 Option in a Parameter Request List Option, as + described in [RFC2131] and [RFC2132]. + + A DHCPv4 server returns the CAPWAP AC Option to the client if the + server policy is configured appropriately and the server is + configured with a list of CAPWAP AC addresses. + + A CAPWAP WTP, acting as a DHCPv4 client, receiving the CAPWAP AC + DHCPv4 Option MAY use the (list of) IP address(es) to locate an AC. + The CAPWAP Protocol [RFC5415] provides guidance on the WTP's + discovery process. + + The WTP, acting as a DHCPv4 client, SHOULD try the records in the + order listed in the CAPWAP AC DHCPv4 Option received from the DHCPv4 + server. + +3. CAPWAP AC DHCPv6 Option + + This section defines a DHCPv6 option that carries a list of 128-bit + (binary) IPv6 addresses indicating one or more CAPWAP ACs available + to the WTP. + + + + + + +Calhoun Standards Track [Page 3] + +RFC 5417 CAPWAP AC DHCP Option March 2009 + + + The DHCPv6 option for CAPWAP has the format shown in the following + figure: + + 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 + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | option-code | option-length | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | | + + + + | | + + AC IPv6 Address + + | | + + + + | | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + | .... | + +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ + + option-code: OPTION_CAPWAP_AC_V6 (52) + + option-length: Length of the 'options' field in octets; MUST be a + multiple of sixteen (16). + + AC IPv6 Address: IPv6 address of a CAPWAP AC that the WTP may use. + The ACs are listed in the order of preference for use by the WTP. + + A DHCPv6 client, acting on behalf of a CAPWAP WTP, MUST request the + CAPWAP AC DHCPv6 Option in a Parameter Request List Option, as + described in [RFC3315]. + + A DHCPv6 server returns the CAPWAP AC Option to the client if the + server policy is configured appropriately and the server is + configured with a list of CAPWAP AC addresses. + + A CAPWAP WTP, acting as a DHCPv6 client, receiving the CAPWAP AC + DHCPv6 Option MAY use the (list of) IP address(es) to locate an AC. + The CAPWAP Protocol [RFC5415] provides guidance on the WTP's + discovery process. + + The WTP, acting as a DHCPv6 client, SHOULD try the records in the + order listed in the CAPWAP AC DHCPv6 Option received from the DHCPv6 + server. + + + + + + + + +Calhoun Standards Track [Page 4] + +RFC 5417 CAPWAP AC DHCP Option March 2009 + + +4. IANA Considerations + + The following DHCPv4 option code for CAPWAP AC Options has been + assigned by IANA: + + Option Name Value Described in + ----------------------------------------------- + OPTION_CAPWAP_AC_V4 138 Section 2 + + The following DHCPv6 option code for CAPWAP AC Options has been + assigned by IANA: + + Option Name Value Described in + ------------------------------------------------ + OPTION_CAPWAP_AC_V6 52 Section 3 + +5. Security Considerations + + The security considerations in [RFC2131], [RFC2132], and [RFC3315] + apply. If an adversary manages to modify the response from a DHCP + server or insert its own response, a WTP could be led to contact a + rogue CAPWAP AC, possibly one that then intercepts call requests or + denies service. CAPWAP's use of Datagram Transport Layer Security + (DTLS) MUST be used to authenticate the CAPWAP peers in the + establishment of the session. + + In most of the networks, the DHCP exchange that delivers the options + prior to network access authentication is neither integrity protected + nor origin authenticated. Therefore, in security sensitive + environments, the options defined in this document SHOULD NOT be the + only methods used to determine to which AC a WTP should connect. The + CAPWAP protocol [RFC5415] defines other AC discovery procedures a WTP + MAY utilize. + +6. Acknowledgments + + The following individuals are acknowledged for their contributions to + this protocol specification: Ralph Droms, Margaret Wasserman. + +7. References + +7.1. Normative References + + [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate + Requirement Levels", BCP 14, RFC 2119, March 1997. + + [RFC2131] Droms, R., "Dynamic Host Configuration Protocol", + RFC 2131, March 1997. + + + +Calhoun Standards Track [Page 5] + +RFC 5417 CAPWAP AC DHCP Option March 2009 + + + [RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor + Extensions", RFC 2132, March 1997. + + [RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., + and M. Carney, "Dynamic Host Configuration Protocol for + IPv6 (DHCPv6)", RFC 3315, July 2003. + + [RFC5415] Montemurro, M., Stanley, D., and P. Calhoun, "CAPWAP + Protocol Specification", RFC 5415, March 2009. + +7.2. Informative References + + [RFC3753] Manner, J. and M. Kojo, "Mobility Related Terminology", + RFC 3753, June 2004. + +Author's Address + + Pat R. Calhoun + Cisco Systems, Inc. + 170 West Tasman Drive + San Jose, CA 95134 + + Phone: +1 408-902-3240 + EMail: pcalhoun@cisco.com + + + + + + + + + + + + + + + + + + + + + + + + + + + +Calhoun Standards Track [Page 6] + |