Re: [OSPF] Poll for WG adoption of draft-hegde-ospf-node-admin-tag

Hannes Gredler <> Wed, 03 September 2014 11:01 UTC

Return-Path: <>
Received: from localhost ( []) by (Postfix) with ESMTP id 7CD691A86E9 for <>; Wed, 3 Sep 2014 04:01:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -2.602
X-Spam-Status: No, score=-2.602 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_LOW=-0.7, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001] autolearn=ham
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id rNd1n1NZlOxl for <>; Wed, 3 Sep 2014 04:01:42 -0700 (PDT)
Received: from ( []) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 8B8E21A86F7 for <>; Wed, 3 Sep 2014 04:01:42 -0700 (PDT)
Received: from hannes-mba.local ( by ( with Microsoft SMTP Server (TLS) id 15.0.1019.16; Wed, 3 Sep 2014 11:01:40 +0000
Received: from hannes-mba.local (localhost []) by hannes-mba.local (Postfix) with ESMTP id 0CF9C2AFB5F; Wed, 3 Sep 2014 13:01:28 +0200 (CEST)
Message-ID: <>
Date: Wed, 3 Sep 2014 13:01:27 +0200
From: Hannes Gredler <>
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.9; rv:31.0) Gecko/20100101 Thunderbird/31.0
MIME-Version: 1.0
To: Peter Psenak <>, <>, Rob Shakir <>
References: <> <> <> <> <> <> <> <> <> <> <15316_1409739908_5406EC84_15316_1787_1_53C29892C857584299CBF5D05346208A071EC421@PEXCVZYM11.corporate.adroot.infra.ftgroup> <>
In-Reply-To: <>
Content-Type: text/plain; charset="windows-1252"; format=flowed
Content-Transfer-Encoding: 7bit
X-Originating-IP: []
X-ClientProxiedBy: ( To (
X-Microsoft-Antispam: BCL:0;PCL:0;RULEID:;UriScan:;
X-Forefront-PRVS: 032334F434
X-Forefront-Antispam-Report: SFV:NSPM; SFS:(6009001)(189002)(199003)(24454002)(479174003)(51704005)(74662001)(74502001)(31966008)(80316001)(83322001)(59896002)(93886004)(15202345003)(76506005)(85306004)(33656002)(87266999)(99396002)(76176999)(54356999)(36756003)(21056001)(65816999)(19580395003)(102836001)(50986999)(50466002)(83506001)(64706001)(83072002)(85852003)(90102001)(65806001)(101416001)(79102001)(80022001)(15975445006)(66066001)(65956001)(86362001)(77982001)(81342001)(64126003)(92566001)(105586002)(76482001)(4396001)(107046002)(46102001)(92726001)(230783001)(81542001)(95666004)(87976001)(20776003)(106356001)(579124003); DIR:OUT; SFP:; SCL:1; SRVR:CO1PR05MB441; H:hannes-mba.local; FPR:; MLV:sfv; PTR:InfoNoRecords; MX:1; A:1; LANG:en;
Cc: "" <>
Subject: Re: [OSPF] Poll for WG adoption of draft-hegde-ospf-node-admin-tag
X-Mailman-Version: 2.1.15
Precedence: list
List-Id: The Official IETF OSPG WG Mailing List <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Wed, 03 Sep 2014 11:01:45 -0000

hi peter,

the question is not so much which registry is better;

we have existing proof-point (rlfa-spec not containing any capabilities)
that there may be the possibility that:

- a well-known, protocol specific tag does not exist
- the operator problem (excluding/including certain nodes
   from PQ capability) still does exist

so it looks like we have a practical case in favor of bruno's argument.

let me draw also some analogy to tagging of IP prefixes here:
draft-hegde-ospf-node-admin-tag is a generic vehicle just as has been conceived for
IP prefixes. - it is correct for the problem described in
RFC5130 we could have been applying application-specific
bits in IP prefixes that control the leaking behavior.

however a different model has been chosen:

1) use generic, application-context-free tags for a prefix
2) write the leaking policy which refers to those tags.

i find the flexibility of that model appealing and i'd
like to have something similar for "nodes" on link-state


On 9/3/14 12:32, Peter Psenak wrote:
>> I agree as a general rule. Yet IMHO we should not kill this
>> possibility. In particular for feature allowing incremental deployment
>> & interaction with non-compliant nodes.
>> One example would have been Remote LFA (RLFA):
>> - the PLR (FRR node) needs to be RLFA compliant. Therefore (potential)
>> communication between PLR regarding their capabilities can be done
>> using IANA/implemented code point.
>> - the PQ node (Merge Point) does not need to be RLFA compliant. And we
>> should keep this property to ease incremental deployment. Therefore
>> communication between PQ and PLR regarding PQ capabilities should/may
>> be done using node tag.  RLFA spec could have defined an IANA
>> registered node tag to be used by PQ (configured by the network
>> operator) to exclude them as PQ candidate. e.g. for PQ node not
>> accepting T-LDP session or nodes which should not be used as PQ per
>> policy.
> why is "IANA registered node tag" any better then IANA registered
> capability bit in the above case?