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Routing IDR BGP cease shutdown This document deprecates the support for the BGP well-know discretionary attribute ATOMIC_AGGREGATE specified in RFC4271. It proposes the changes to RFC4271 to remove its support. 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 .

The ATOMIC_AGGREGATE well-known discretionary attribute is specified in in section 5.1.6. This document specifies the changes to RFC4271 in order to remove the ATOMIC_AGGREGATE attribute.

delete the following text:

f) ATOMIC_AGGREGATE (Type Code 6) ATOMIC_AGGREGATE is a well-known discretionary attribute of length 0. Usage of this attribute is defined in 5.1.6.

1: Section 5.0 should have the following changes (p. 24) Old:

attribute EBGP IBGP ORIGIN mandatory mandatory AS_PATH mandatory mandatory NEXT_HOP mandatory mandatory MULTI_EXIT_DISC discretionary discretionary LOCAL_PREF see Section 5.1.5 required ATOMIC_AGGREGATE see Section 5.1.6 and 9.1.4 AGGREGATOR discretionary discretionary

New:

attribute EBGP IBGP ORIGIN mandatory mandatory AS_PATH mandatory mandatory NEXT_HOP mandatory mandatory MULTI_EXIT_DISC discretionary discretionary LOCAL_PREF see Section 5.1.5 required AGGREGATOR discretionary discretionary

2: Delete Section 5.1.6

3: Changes to section 9.1.4 Old: If a BGP speaker chooses to aggregate, then it SHOULD either include all ASes used to form the aggregate in an AS_SET, or add the ATOMIC_AGGREGATE attribute to the route. New If a BGP speaker chooses to aggregate, then it SHOULD either include all ASes used to form the aggregate in an AS_SET. delete the following text: "In particular, a route that carries the ATOMIC_AGGREGATE attribute MUST NOT be de-aggregated."

Text to delete:

ATOMIC_AGGREGATE: If at least one of the routes to be aggregated has ATOMIC_AGGREGATE path attribute, then the aggregated route SHALL have this attribute as well.

Input needed here.

An ATOMIC_AGGREGATE attribute received should be silently ignored.

IANA Is asked to deprecate the BGP Attribute: Atomic_Aggregate with this document as reference.

Deprecating a BGP attribute does not change the BGP messages sent on over a secure transport. Users of this mechanism should be aware that unless a transport that provides integrity (such as TCP-AO) is used for the BGP session in question, BGP Attributes can be forged. This could become an attack vector. Unless a transport that provides confidentiality (such as IPSec) is used, BGP attributes Communication messages could be snooped by an attacker allowing access to BGP attributes. These issues are common to any BGP message but may be of greater interest in the context of this proposal since a BGP Attribute is being deleted.

The author would like to gratefully acknowledge the IDR WG discussion