[pim] [Technical Errata Reported] RFC4601 (2927)

RFC Errata System <rfc-editor@rfc-editor.org> Tue, 09 August 2011 10:23 UTC

To: fenner@research.att.com, M.Handley@cs.ucl.ac.uk, holbrook@arastra.com, kouvelas@cisco.com, stbryant@cisco.com, adrian@olddog.co.uk, mmcbride7@gmail.com, stig@venaas.com
From: RFC Errata System <rfc-editor@rfc-editor.org>
Message-Id: <20110809102345.D1BDE98C4F9@rfc-editor.org>
Date: Tue, 09 Aug 2011 03:23:45 -0700
Cc: wcang@sfc.wide.ad.jp, pim@ietf.org, rfc-editor@rfc-editor.org
Subject: [pim] [Technical Errata Reported] RFC4601 (2927)
Precedence: list

The following errata report has been submitted for RFC4601,
"Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)".

--------------------------------------
You may review the report below and at:
http://www.rfc-editor.org/errata_search.php?rfc=4601&eid=2927

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Type: Technical
Reported by: Ang Way Chuang <wcang@sfc.wide.ad.jp>

Section: 4.2.2

Original Text
-------------
     void
     Update_SPTbit(S,G,iif) {
       if ( iif == RPF_interface(S)
             AND JoinDesired(S,G) == TRUE
             AND ( DirectlyConnected(S) == TRUE
                   OR RPF_interface(S) != RPF_interface(RP(G))
                   OR inherited_olist(S,G,rpt) == NULL
                   OR ( ( RPF'(S,G) == RPF'(*,G) ) AND
                        ( RPF'(S,G) != NULL ) )
                   OR ( I_Am_Assert_Loser(S,G,iif) ) {
          Set SPTbit(S,G) to TRUE
       }
     }

Corrected Text
--------------
     void
     Update_SPTbit(S,G,iif) {
       if ( iif == RPF_interface(S)
             AND JoinDesired(S,G) == TRUE
             AND ( DirectlyConnected(S) == TRUE
                   OR RPF_interface(S) != RPF_interface(RP(G))
                   OR inherited_olist(S,G,rpt) == NULL
                   OR ( ( RPF'(S,G) == RPF'(*,G) ) AND
                        ( RPF'(S,G) != NULL ) )
                   OR ( I_Am_Assert_Loser(S,G,iif) ) ) ) {
          Set SPTbit(S,G) to TRUE
       }
     }

Notes
-----
The logical evaluation is not properly enclosed. The RFC also doesn't mention the reason for the extra checking on the RPF'(S,G) != NULL. It is non-obvious to me. If the check on iif == RPF_interface(S) passes, how would there be any condition where RPF'(S,G) == NULL?

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-------------
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RFC4601 (draft-ietf-pim-sm-v2-new-12)
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Title               : Protocol Independent Multicast - Sparse Mode (PIM-SM): Protocol Specification (Revised)
Publication Date    : August 2006
Author(s)           : B. Fenner, M. Handley, H. Holbrook, I. Kouvelas
Category            : PROPOSED STANDARD
Source              : Protocol Independent Multicast
Area                : Routing
Stream              : IETF
Verifying Party     : IESG

[pim] [Technical Errata Reported] RFC4601 (2927) RFC Errata System
Re: [pim] [Technical Errata Reported] RFC4601 (29… Adrian Farrel