--- 1/draft-ietf-idr-bgp-extended-messages-27.txt 2019-02-13 14:13:10.308006961 -0800 +++ 2/draft-ietf-idr-bgp-extended-messages-28.txt 2019-02-13 14:13:10.328007452 -0800 @@ -1,21 +1,21 @@ Network Working Group R. Bush Internet-Draft Internet Initiative Japan Updates: 4271 (if approved) K. Patel Intended status: Standards Track Arrcus, Inc. -Expires: June 5, 2019 D. Ward +Expires: August 17, 2019 D. Ward Cisco Systems - December 2, 2018 + February 13, 2019 Extended Message support for BGP - draft-ietf-idr-bgp-extended-messages-27 + draft-ietf-idr-bgp-extended-messages-28 Abstract The BGP specification mandates a maximum BGP message size of 4096 octets. As BGP is extended to support newer AFI/SAFIs and other features, there is a need to extend the maximum message size beyond 4096 octets. This document updates the BGP specification RFC4271 by providing an extension to BGP to extend its current maximum message size from 4096 octets to 65535 octets for all except the OPEN message. @@ -36,25 +36,25 @@ Internet-Drafts are working documents of the Internet Engineering Task Force (IETF). Note that other groups may also distribute working documents as Internet-Drafts. The list of current Internet- Drafts is at https://datatracker.ietf.org/drafts/current/. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any time. It is inappropriate to use Internet-Drafts as reference material or to cite them other than as "work in progress." - This Internet-Draft will expire on June 5, 2019. + This Internet-Draft will expire on August 17, 2019. Copyright Notice - Copyright (c) 2018 IETF Trust and the persons identified as the + Copyright (c) 2019 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 (https://trustee.ietf.org/license-info) in effect on the date of publication of this document. Please review these documents carefully, as they describe your rights and restrictions with respect to this document. Code Components extracted from this document must include Simplified BSD License text as described in Section 4.e of the Trust Legal Provisions and are provided without warranty as @@ -62,36 +62,36 @@ Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2 2. BGP Extended Message . . . . . . . . . . . . . . . . . . . . 2 3. Extended Message Capability for BGP . . . . . . . . . . . . . 3 4. Operation . . . . . . . . . . . . . . . . . . . . . . . . . . 3 5. Error Handling . . . . . . . . . . . . . . . . . . . . . . . 4 6. Changes to RFC4271 . . . . . . . . . . . . . . . . . . . . . 4 7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 4 - 8. Security Considerations . . . . . . . . . . . . . . . . . . . 4 + 8. Security Considerations . . . . . . . . . . . . . . . . . . . 5 9. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 5 10. References . . . . . . . . . . . . . . . . . . . . . . . . . 5 10.1. Normative References . . . . . . . . . . . . . . . . . . 5 10.2. Informative References . . . . . . . . . . . . . . . . . 5 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 6 1. Introduction The BGP specification [RFC4271] mandates a maximum BGP message size of 4096 octets. As BGP is extended to support newer AFI/SAFIs and - newer capabilities (e.g., [I-D.ietf-sidr-bgpsec-protocol]), there is - a need to extend the maximum message size beyond 4096 octets. This - draft provides an extension to BGP to extend its current message size - limit from 4096 octets to 65535 octets for all except the OPEN - message. + newer capabilities (e.g., BGPsec, [RFC8205], BGP-LS, [RFC7752]), + there is a need to extend the maximum message size beyond 4096 + octets. This draft provides an extension to BGP to extend its + current message size limit from 4096 octets to 65535 octets for all + except the OPEN message. 2. BGP Extended Message A BGP message over 4096 octets in length is a BGP Extended Message. BGP Extended Messages have maximum message size of 65535 octets. The smallest message that may be sent consists of a BGP header without a data portion (19 octets). 3. Extended Message Capability for BGP @@ -106,43 +106,50 @@ Extended Messages, and BGP Extended Messages MUST NOT be sent to it. The BGP Extended Message Capability is a new BGP Capability [RFC5492] defined with Capability code 6 and Capability length 0. 4. Operation A BGP speaker that is capable of sending and receiving BGP Extended Messages SHOULD advertise the BGP Extended Message Capability to the peer using BGP Capabilities Advertisement [RFC5492]. A BGP speaker - MAY send Extended Messages to its peer only if it has received the - Extended Message Capability from that peer. + MAY send Extended Messages to its peer only if it has sent and + received the Extended Message Capability from that peer. - The Extended Message Capability only applies to all messages except - for the OPEN message. This exception is made to reduce compexity of + The Extended Message Capability applies to all messages except for + the OPEN message. This exception is made to reduce complexity of providing backward compatibility An implementation that advertises support for BGP Extended Messages MUST be capable of receiving a message with a length up to and including 65535 octets. Applications generating information which might be encapsulated within BGP messages MUST limit the size of their payload to take the maximum message size into account. + If a BGP update with a payload longer than 4096 octets is received by + a BGP listener who has neither advertised nor agreed to accept BGP + Extended Messages, the listener MUST treat this as a malformed update + message, and MUST raise an UPDATE Message Error (see [RFC4271] Sec + 6.3). + A BGP announcement will, in the normal case, propagate throughout the BGP speaking Internet; and there will undoubtedly be BGP speakers which do not have the Extended Message capability. Therefore, putting an attribute which can not be decomposed to 4096 octets or less in an Extended Message is a likely path to routing failure. It is RECOMMENDED that BGP protocol developers and implementers are conservative in their application and use of Extended Messages. + Future protocol specifications will need to describe how to handle peers which can only accommodate 4096 octet messages. 5. Error Handling A BGP speaker that has the ability to use Extended Messages but has not advertised the BGP Extended Messages capability, presumably due to configuration, SHOULD NOT accept an Extended Message. A speaker MAY implement a more liberal policy and accept Extended Messages, even from a peer to which it has not advertised the capability, in @@ -220,23 +227,29 @@ [RFC4272] Murphy, S., "BGP Security Vulnerabilities Analysis", RFC 4272, DOI 10.17487/RFC4272, January 2006, . [RFC5492] Scudder, J. and R. Chandra, "Capabilities Advertisement with BGP-4", RFC 5492, DOI 10.17487/RFC5492, February 2009, . 10.2. Informative References - [I-D.ietf-sidr-bgpsec-protocol] - Lepinski, M., "BGPSEC Protocol Specification", draft-ietf- - sidr-bgpsec-protocol-07 (work in progress), February 2013. + [RFC7752] Gredler, H., Ed., Medved, J., Previdi, S., Farrel, A., and + S. Ray, "North-Bound Distribution of Link-State and + Traffic Engineering (TE) Information Using BGP", RFC 7752, + DOI 10.17487/RFC7752, March 2016, + . + + [RFC8205] Lepinski, M., Ed. and K. Sriram, Ed., "BGPsec Protocol + Specification", RFC 8205, DOI 10.17487/RFC8205, September + 2017, . Authors' Addresses Randy Bush Internet Initiative Japan 5147 Crystal Springs Bainbridge Island, Washington 98110 United States of America Email: randy@psg.com