Re: [Lsr] OSPF Routing with Cross-Address Family Traffic Engineering Tunnels - draft-ietf-ospf-xaf-te-04.txt

Anton Smirnov <> Thu, 25 October 2018 16:57 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id 33B41130EC0 for <>; Thu, 25 Oct 2018 09:57:22 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -14.5
X-Spam-Status: No, score=-14.5 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_HI=-5, SPF_PASS=-0.001, URIBL_BLOCKED=0.001, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: (amavisd-new); dkim=pass (1024-bit key)
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id CVnR7NgxPk5O for <>; Thu, 25 Oct 2018 09:57:20 -0700 (PDT)
Received: from ( []) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 4B2D9130EC3 for <>; Thu, 25 Oct 2018 09:57:19 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;;; l=18625; q=dns/txt; s=iport; t=1540486639; x=1541696239; h=subject:to:references:from:message-id:date:mime-version: in-reply-to; bh=5ikfzH+h1wDaQ+PFvFik4xRebf00RBQh36Nh7ehUOAg=; b=fckx1XQHghe5lpJv2cc2M0o+fPLVN7D9aCtL3AsPJwbjcO4eRT9pHCyi zeLzQCcBHWzkm4FpoUmD+3UPPp0gv2NwX9tJYTyPj8CXBWH71/W7/70Ll WvPz3biN1umwQ8m14xxViTqU0m5AawukH4Zru9E7DVMTa+xaxL84f4/zW o=;
X-IronPort-AV: E=Sophos;i="5.54,425,1534809600"; d="scan'208,217";a="7535104"
Received: from (HELO ([]) by with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Oct 2018 16:57:17 +0000
Received: from ( []) (authenticated bits=0) by (8.15.2/8.15.2) with ESMTPSA id w9PGvGI9028813 (version=TLSv1.2 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 25 Oct 2018 16:57:17 GMT
To: "Ketan Talaulikar (ketant)" <>, "Acee Lindem (acee)" <>, "" <>
References: <> <>
From: Anton Smirnov <>
Organization: Cisco Systems
Message-ID: <>
Date: Thu, 25 Oct 2018 18:57:11 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2
MIME-Version: 1.0
In-Reply-To: <>
Content-Type: multipart/alternative; boundary="------------9C40968537A390962B70E5CE"
Content-Language: en-US
X-Authenticated-User: asmirnov
Archived-At: <>
Subject: Re: [Lsr] OSPF Routing with Cross-Address Family Traffic Engineering Tunnels - draft-ietf-ospf-xaf-te-04.txt
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Link State Routing Working Group <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Thu, 25 Oct 2018 16:57:22 -0000

    Hi Ketan,

1. I am not sure I understood the question. Your example says "using the 
TE topology from OSPFv2 to compute a tunnel". In that case TE router ID 
is an IPv4 address. So no, advertising IPv6 address won't help to 
identify the tunnel.

2. my opinion (not discussed with other authors): RFC 3906 is 
Informational RFC, so it is not mandatory for implementation to follow. 
I think we can insert mention to that RFC somewhere in the Introduction 
but wording should be sufficiently weak (like "one possible example of 
route computation algorithm...").


On 10/24/18 12:06, Ketan Talaulikar (ketant) wrote:
> Hello All,
> I support this simple but important extension.
> A couple of minor comments on the draft:
> 1)Sec 3 says
>    A node that implements X-AF routing SHOULD advertise, in the
>    corresponding Node Local Address sub-TLV, all X-AF IPv4 and IPv6
>    addresses local to the router that can be used by Constrained SPF
>    (CSPF) to calculate MPLS TE LSPs.  In general, OSPF SHOULD advertise
>    the IP address listed in the Router Address TLV [RFC3630 
> <>] [RFC5329 
> <>]
>    of the X-AF instance maintaining the MPLS TE database, plus any
>    additional local addresses advertised by the X-AF OSPF instance in
>    its Node Local Address sub-TLVs.  An implementation MAY advertise
>    other local X-AF addresses.
> Generally speaking, should the IP address (TE router ID in common 
> terms) which is candidate for inclusion in the Router Address TLV not 
> be a MUST candidate for X-AF advertisement?
> I also have a question about the first statement with the SHOULD in 
> it. Consider we are using the TE topology from OSPFv2 to compute a 
> tunnel for use with OSPFv3. Any IPv6 addresses associated with the 
> OSPFv3 instance on a router would be advertised as a Node attribute 
> and would not help identify a specific link. So practically, if any 
> IPv6 addresses (if at all) were to be used for CSPF then it would just 
> identify the node – in this case, isn’t advertising the IPv6 address 
> (TE router ID used in Router Address TLV) sufficient?
> For practical deployment, it think it would help if this was clarified 
> that we really need only the TE Router ID Address to go X-AF in 
> most/general cases and not the others?
> 2)Isn’t the mapping algorithm in Sec 3 actually going to be used for 
> IGP short-cut use-case with its reference to the IGP cost of the 
> tunnel? If so, would a reference to rfc3906 be helpful in this document.
> Thanks,
> Ketan
> *From:*Lsr <>; *On Behalf Of *Acee Lindem (acee)
> *Sent:* 23 October 2018 03:55
> *To:*
> *Subject:* [Lsr] OSPF Routing with Cross-Address Family Traffic 
> Engineering Tunnels - draft-ietf-ospf-xaf-te-04.txt
> This begins an LSR WG last call for the subject draft. Please send 
> your comments to this list prior to 12:00 AM GMT, November 13^th , 
> 2018. While its only an 8 page document, I added an extra week due to 
> the IETF. Please let me know if anyone needs any more time.
> Thanks,
> Acee
> _______________________________________________
> Lsr mailing list