--- 1/draft-ietf-idr-rfc2858bis-08.txt 2006-03-06 22:12:43.000000000 +0100 +++ 2/draft-ietf-idr-rfc2858bis-09.txt 2006-03-06 22:12:43.000000000 +0100 @@ -1,19 +1,19 @@ Network Working Group Tony Bates (Cisco Systems) Internet Draft Ravi Chandra (Sonoa Systems) -Expiration Date: July 2006 Dave Katz (Juniper Networks) +Expiration Date: September 2006 Dave Katz (Juniper Networks) Obsoles RFC2858 Yakov Rekhter (Juniper Networks) Multiprotocol Extensions for BGP-4 - draft-ietf-idr-rfc2858bis-08.txt + draft-ietf-idr-rfc2858bis-09.txt Status of this Memo Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. Internet-Drafts are draft documents valid for a maximum of six months and may be updated, replaced, or obsoleted by other documents at any @@ -96,50 +96,32 @@ This is an optional non-transitive attribute that can be used for the following purposes: (a) to advertise a feasible route to a peer (b) to permit a router to advertise the Network Layer address of the router that should be used as the next hop to the destinations listed in the Network Layer Reachability Information field of the MP_NLRI attribute. - (c) to allow a given router to report some or all of the - Subnetwork Points of Attachment (SNPAs) that exist within the - local system - The attribute is encoded as shown below: +---------------------------------------------------------+ | Address Family Identifier (2 octets) | +---------------------------------------------------------+ | Subsequent Address Family Identifier (1 octet) | +---------------------------------------------------------+ | Length of Next Hop Network Address (1 octet) | +---------------------------------------------------------+ | Network Address of Next Hop (variable) | +---------------------------------------------------------+ - | Number of SNPAs (1 octet) | - +---------------------------------------------------------+ - | Length of first SNPA(1 octet) | - +---------------------------------------------------------+ - | First SNPA (variable) | - +---------------------------------------------------------+ - | Length of second SNPA (1 octet) | - +---------------------------------------------------------+ - | Second SNPA (variable) | - +---------------------------------------------------------+ - | ... | - +---------------------------------------------------------+ - | Length of Last SNPA (1 octet) | - +---------------------------------------------------------+ - | Last SNPA (variable) | + | Reserved (1 octet) | +---------------------------------------------------------+ | Network Layer Reachability Information (variable) | +---------------------------------------------------------+ The use and meaning of these fields are as follows: Address Family Identifier (AFI): This field in combination with the Subsequent Address Family Identifier field identifies the Network Layer protocol @@ -164,40 +146,23 @@ "Network Address of Next Hop" field as measured in octets. Network Address of Next Hop: A variable length field that contains the Network Address of the next router on the path to the destination system. The Network Layer protocol associated with the Network Address of the Next Hop is identified by a combination of carried in the attribute. - Number of SNPAs: - - A 1 octet field which contains the number of distinct SNPAs to - be listed in the following fields. The value 0 SHALL be used - to indicate that no SNPAs are listed in this attribute. - - Length of Nth SNPA: - - A 1 octet field whose value expresses the length of the "Nth - SNPA of Next Hop" field as measured in semi-octets - - Nth SNPA of Next Hop: + Reserved: - A variable length field that contains an SNPA of the router - whose Network Address is contained in the "Network Address of - Next Hop" field. The field length is an integral number of - octets in length, namely the rounded-up integer value of one - half the SNPA length expressed in semi-octets; if the SNPA - contains an odd number of semi-octets, a value in this field - MUST be padded with a trailing all-zero semi-octet. + A 1 octet field that SHOULD be set to 0. Network Layer Reachability Information (NLRI): A variable length field that lists NLRI for the feasible routes that are being advertised in this attribute. The semantics of NLRI is identified by a combination of carried in the attribute. When the Subsequent Address Family Identifier field is set to one of the values defined in this document, each NLRI is @@ -411,20 +376,24 @@ This document removes the definition of SAFI 3, and deprecates SAFI 3. This document changes partitioning of the SAFI space. Specifically, in RFC2858 SAFI values 128 through 240 were part of the "private use" range. This document specifies that of this range, allocations which are currently in use are to be recognized by IANA, and that unused values, namely 130, 131, 135 through 139, and 141 through 240 should be considered reserved. + This document renames the Number of SNPAs field to Reserved, and + removes the rest of the SNPA-related information from the + MP_REACH_NLRI attribute. + 11. Comparison with RFC2283 This document restricts the MP_REACH_NLRI attribute to carry only a single instance of . This document restricts the MP_UNREACH_NLRI attribute to carry only a single instance of . This document clarifies handling of an UPDATE message that carries no NLRI, other than the one encoded in the MP_REACH_NLRI attribute.