draft-ietf-idr-aigp-16.txt   draft-ietf-idr-aigp-17.txt 
Network Working Group Pradosh Mohapatra Network Working Group Pradosh Mohapatra
Internet Draft Cumulus Networks Internet Draft Cumulus Networks
Intended Status: Proposed Standard Intended Status: Proposed Standard
Expires: September 25, 2014 Rex Fernando Expires: October 8, 2014 Rex Fernando
Eric C. Rosen Eric C. Rosen
Cisco Systems, Inc. Cisco Systems, Inc.
James Uttaro James Uttaro
ATT ATT
March 25, 2014 April 8, 2014
The Accumulated IGP Metric Attribute for BGP The Accumulated IGP Metric Attribute for BGP
draft-ietf-idr-aigp-16.txt draft-ietf-idr-aigp-17.txt
Abstract Abstract
Routing protocols that have been designed to run within a single Routing protocols that have been designed to run within a single
administrative domain ("IGPs") generally do so by assigning a metric administrative domain ("IGPs") generally do so by assigning a metric
to each link, and then choosing as the installed path between two to each link, and then choosing as the installed path between two
nodes the path for which the total distance (sum of the metric of nodes the path for which the total distance (sum of the metric of
each link along the path) is minimized. BGP, designed to provide each link along the path) is minimized. BGP, designed to provide
routing over a large number of independent administrative domains routing over a large number of independent administrative domains
("autonomous systems"), does not make its path selection decisions ("autonomous systems"), does not make its path selection decisions
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3.3. Restrictions on Sending/Receiving 3.3. Restrictions on Sending/Receiving
An implementation that supports the AIGP attribute MUST support a An implementation that supports the AIGP attribute MUST support a
per-session configuration item, AIGP_SESSION, that indicates whether per-session configuration item, AIGP_SESSION, that indicates whether
the attribute is enabled or disabled for use on that session. the attribute is enabled or disabled for use on that session.
- The default value of AIGP_SESSION, for EBGP sessions, MUST be - The default value of AIGP_SESSION, for EBGP sessions, MUST be
"disabled". "disabled".
- The default value of AIGP_SESSION, for IBGP and confederation- - The default value of AIGP_SESSION, for IBGP and confederation-
EBGP sessions, SHOULD be "enabled." EBGP [BGP-CONFED] sessions, SHOULD be "enabled."
The AIGP attribute MUST NOT be sent on any BGP session for which The AIGP attribute MUST NOT be sent on any BGP session for which
AIGP_SESSION is disabled. AIGP_SESSION is disabled.
If an AIGP attribute is received on a BGP session for which If an AIGP attribute is received on a BGP session for which
AIGP_SESSION is disabled, the attribute MUST be treated exactly as if AIGP_SESSION is disabled, the attribute MUST be treated exactly as if
it were an unrecognized non-transitive attribute. That is, "it MUST it were an unrecognized non-transitive attribute. That is, "it MUST
be quietly ignored and not passed along to other BGP peers" (see be quietly ignored and not passed along to other BGP peers" (see
[BGP], section 5). However, the fact that the attribute was received [BGP], section 5). However, the fact that the attribute was received
SHOULD be logged (in a rate-limited manner). SHOULD be logged (in a rate-limited manner).
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11. Informative References 11. Informative References
[ADD-PATH] "Advertisement of Multiple Paths in BGP", D. Walton, A. [ADD-PATH] "Advertisement of Multiple Paths in BGP", D. Walton, A.
Retana, E. Chen, J. Scudder, draft-ietf-idr-add-paths-09.txt, October Retana, E. Chen, J. Scudder, draft-ietf-idr-add-paths-09.txt, October
2013. 2013.
[BESTEXT], "Advertisement of the Best External Route in BGP", P. [BESTEXT], "Advertisement of the Best External Route in BGP", P.
Marques, R. Fernando, E. Chen, P. Mohapatra, H. Gredler, draft-ietf- Marques, R. Fernando, E. Chen, P. Mohapatra, H. Gredler, draft-ietf-
idr-best-external-05.txt, January 2012. idr-best-external-05.txt, January 2012.
[BGP-CONFED] "Autonomous System Confederations for BGP", P. Traina,
D. McPherson, J. Scudder, RFC 5065, August 2007
[BGP-ERROR] "Revised Error Handling for BGP UPDATE Messages", J. [BGP-ERROR] "Revised Error Handling for BGP UPDATE Messages", J.
Scudder, E. Chen, P. Mohapatra, K. Patel, draft-ietf-idr-error- Scudder, E. Chen, P. Mohapatra, K. Patel, draft-ietf-idr-error-
handling-06.txt, February 2014. handling-06.txt, February 2014.
[LDP-IGP-SYNC] "LDP IGP Synchronization", M. Jork, A. Atlas, L. Fang, [LDP-IGP-SYNC] "LDP IGP Synchronization", M. Jork, A. Atlas, L. Fang,
RFC 5443, March 2009. RFC 5443, March 2009.
[RFC2119] "Key words for use in RFCs to Indicate Requirement [RFC2119] "Key words for use in RFCs to Indicate Requirement
Levels.", S. Bradner, March 1997. Levels.", S. Bradner, March 1997.
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