--- 1/draft-ietf-idr-bgp4-multiprotocol-00.txt 2006-02-04 23:31:00.000000000 +0100 +++ 2/draft-ietf-idr-bgp4-multiprotocol-01.txt 2006-02-04 23:31:00.000000000 +0100 @@ -1,23 +1,23 @@ Network Working Group Tony Bates Internet Draft Cisco Systems -Expiration Date: February 1998 Ravi Chandra +Expiration Date: March 1998 Ravi Chandra Cisco Systems Dave Katz Juniper Networks Yakov Rekhter Cisco Systems Multiprotocol Extensions for BGP-4 - draft-ietf-idr-bgp4-multiprotocol-00.txt + draft-ietf-idr-bgp4-multiprotocol-01.txt 1. Status of this Memo This document is an Internet-Draft. 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 @@ -118,25 +118,22 @@ | Length of second SNPA (1 octet) | +---------------------------------------------------------+ | Second SNPA (variable) | +---------------------------------------------------------+ | ... | +---------------------------------------------------------+ | Length of Last SNPA (1 octet) | +---------------------------------------------------------+ | Last SNPA (variable) | +---------------------------------------------------------+ - | Network Layer Reachability Information Length (2 octets)| - +---------------------------------------------------------+ | Network Layer Reachability Information (variable) | +---------------------------------------------------------+ - The use and meaning of these fields are as follows: Address Family Identifier: This field carries the identity of the Network Layer protocol associated with the Network Address that follows. Presently defined values for this field are specified in RFC1700 (see the Address Family Numbers section). Subsequent Address Family Identifier: @@ -169,25 +166,20 @@ Nth SNPA of Next Hop: 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 will be padded with a trailing all-zero semi-octet. - Network Layer Reachability Information Length: - - This 2-octets unsigned integer indicates the total length of - the Network Layer Reachability Information field in octets. - Network Layer Reachability Information: A variable length field that lists NLRI for the feasible routes that are being advertised in this attribute. When the Subsequent Address Family Identifier field is set to one of the values defined in this document, each NLRI is encoded as specified in the "NLRI encoding" section of this document. The next hop information carried in the MP_REACH_NLRI path attribute defines the Network Layer address of the border router that should be @@ -228,62 +220,52 @@ An UPDATE message that carries the MP_REACH_NLRI must also carry the ORIGIN and the AS_PATH attributes (both in EBGP and in IBGP exchanges). Moreover, in IBGP exchanges such a message must also carry the LOCAL_PREF attribute. If such a message is received from an external peer, the local system shall check whether the leftmost AS in the AS_PATH attribute is equal to the autonomous system number of the peer than sent the message. If that is not the case, the local system shall send the NOTIFICATION message with Error Code UPDATE Message Error, and the Error Subcode set to Malformed AS_PATH. - When an UPDATE message carries the MP_REACH_NLRI attribute, the - attribute shall be placed after all other attributes in the message. - 5. Multiprotocol Unreachable NLRI - MP_UNREACH_NLRI (Type Code 15): This is an optional non-transitive attribute that can be used for the purpose of withdrawing multiple unfeasible routes from service. The attribute contains one or more triples
, where each triple is encoded as shown below: +---------------------------------------------------------+ | Address Family Identifier (2 octets) | +---------------------------------------------------------+ | Subsequent Address Family Identifier (1 octet) | +---------------------------------------------------------+ - | Unfeasible Routes Length (2 octets) | - +---------------------------------------------------------+ | Withdrawn Routes (variable) | +---------------------------------------------------------+ The use and the meaning of these fields are as follows: Address Family Identifier: This field carries the identity of the Network Layer protocol associated with the NLRI that follows. Presently defined values for this field are specified in RFC1700 (see the Address Family Numbers section). Subsequent Address Family Identifier: This field provides additional information about the type of the Network Layer Reachability Information carried in the attribute. - Unfeasible Routes Length: - - This 2-octets unsigned integer indicates the total length of - the Withdrawn Routes field in octets. - Withdrawn Routes: A variable length field that lists NLRI for the routes that are being withdrawn from service. When the Subsequent Address Family Identifier field is set to one of the values defined in this document, each NLRI is encoded as specified in the "NLRI encoding" section of this document. An UPDATE message that contains the MP_UNREACH_NLRI is not required to carry any other path attributes.