Subject: [Idr] [Technical Errata Reported] RFC4456 (3898)

From: RFC Errata System <[email-masked]>
Date: Sun, 23 Feb 2014 23:47:45 -0800 (PST)

The following errata report has been submitted for RFC4456,
"BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)".

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You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=4456&eid=3898

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Type: Technical
Reported by: Gunjan Bansal <[email-masked]>

Section: 8

Original Text
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ORIGINATOR_ID

   ORIGINATOR_ID is a new optional, non-transitive BGP attribute of Type
   code 9.  This attribute is 4 bytes long and it will be created by an
   RR in reflecting a route.  This attribute will carry the BGP
   Identifier of the originator of the route in the local AS.  A BGP
   speaker SHOULD NOT create an ORIGINATOR_ID attribute if one already
   exists.  A router that recognizes the ORIGINATOR_ID attribute SHOULD
   ignore a route received with its BGP Identifier as the ORIGINATOR_ID.

CLUSTER_LIST

   CLUSTER_LIST is a new, optional, non-transitive BGP attribute of Type
   code 10.  It is a sequence of CLUSTER_ID values representing the
   reflection path that the route has passed.

   When an RR reflects a route, it MUST prepend the local CLUSTER_ID to
   the CLUSTER_LIST.  If the CLUSTER_LIST is empty, it MUST create a new
   one.  Using this attribute an RR can identify if the routing
   information has looped back to the same cluster due to
   misconfiguration.  If the local CLUSTER_ID is found in the
   CLUSTER_LIST, the advertisement received SHOULD be ignored.

Corrected Text
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Notes
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Although the guideline exists for the "egress" reflected routes (RR should create ORIGINATOR_ID if none exists, prepend its own ClusterId in CLUSTER_LIST), there is no guideline on how the routes received from iBGP peers be treated if "only one" attribute (ORIGINATOR_ID or CLUSTER_LIST) is present. 
Should such routes be dropped (Considering them as a malformed routes ?)

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RFC4456 (draft-ietf-idr-rfc2796bis-02)
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Title               : BGP Route Reflection: An Alternative to Full Mesh Internal BGP (IBGP)
Publication Date    : April 2006
Author(s)           : T. Bates, E. Chen, R. Chandra
Category            : DRAFT STANDARD
Source              : Inter-Domain Routing
Area                : Routing
Stream              : IETF
Verifying Party     : IESG