Return-Path: X-Original-To: ospf@core3.amsl.com Delivered-To: ospf@core3.amsl.com Received: from localhost (localhost [127.0.0.1]) by core3.amsl.com (Postfix) with ESMTP id 4C5C43A69E8 for ; Wed, 2 Sep 2009 16:32:36 -0700 (PDT) X-Virus-Scanned: amavisd-new at amsl.com X-Spam-Flag: NO X-Spam-Score: -2.414 X-Spam-Level: X-Spam-Status: No, score=-2.414 tagged_above=-999 required=5 tests=[AWL=0.184, BAYES_00=-2.599, HTML_MESSAGE=0.001] Received: from mail.ietf.org ([64.170.98.32]) by localhost (core3.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 5u6jQaVbgFZn for ; Wed, 2 Sep 2009 16:32:35 -0700 (PDT) Received: from mgate.redback.com (mgate.redback.com [155.53.3.41]) by core3.amsl.com (Postfix) with ESMTP id 52DAA3A67FD for ; Wed, 2 Sep 2009 16:32:35 -0700 (PDT) X-IronPort-AV: E=Sophos;i="4.44,321,1249282800"; d="scan'208,217";a="4977528" Received: from prattle.redback.com ([155.53.12.9]) by mgate.redback.com with ESMTP; 02 Sep 2009 16:32:10 -0700 Received: from localhost (localhost [127.0.0.1]) by prattle.redback.com (Postfix) with ESMTP id 3F9849AA9B4; Wed, 2 Sep 2009 16:32:10 -0700 (PDT) Received: from prattle.redback.com ([127.0.0.1]) by localhost (prattle [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 24380-09; Wed, 2 Sep 2009 16:32:10 -0700 (PDT) Received: from [IPv6???1] (svilogin-1.sj.us.am.ericsson.se [155.53.154.39]) by prattle.redback.com (Postfix) with ESMTP id CBB5C9AA9B3; Wed, 2 Sep 2009 16:32:09 -0700 (PDT) In-Reply-To: References: Mime-Version: 1.0 (Apple Message framework v753.1) Content-Type: multipart/alternative; boundary=Apple-Mail-5-896705659 Message-Id: From: Acee Lindem Date: Wed, 2 Sep 2009 19:32:08 -0400 To: suketu soni X-Mailer: Apple Mail (2.753.1) Cc: ospf@ietf.org Subject: Re: [OSPF] Describing a point-to-point link in Router LSA X-BeenThere: ospf@ietf.org X-Mailman-Version: 2.1.9 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, 02 Sep 2009 23:32:36 -0000 --Apple-Mail-5-896705659 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi Suketu, See inline. On Sep 2, 2009, at 3:59 AM, suketu soni wrote: > Hi, > > A point-to-point link type is included twice in a Router-LSA. > > 1) As Link Type = 1 (p2p), with neighboring router's RID as Link > ID. This happens when the adjacency status is FULL. > > 2) As Link Type = 3 (stub), with IP subnet address as Link ID. This > happens when the interface state is point-to-point, regardless of > the status of adjacency. > > I found out that if a point-to-point link is used as passive- > interface, then adjacency will not be formed. Hence, link type = 1 > advertizement will be absent. However, a link type = 3 > advertizement of such a link makes it reachable. > > Please share more examples where it helps to advertize a p2p link > type in two ways. My intention is to understand the need for having > two types of advertizements for the same p2p link. The two links serve completely different purposes. The type 1 link is to advertise connectivity to the other router, i.e., an edge in the SPF graph, while the type 3 link is to advertise the IP subnet. Thanks, Acee > > Thank you. > > Best wishes > Suketu Soni > One blink is all it takes for the world to change. One click and > MSN India helps you catch up Try it! > _______________________________________________ > OSPF mailing list > OSPF@ietf.org > https://www.ietf.org/mailman/listinfo/ospf --Apple-Mail-5-896705659 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=US-ASCII Hi Suketu, 
See inline. 
On Sep 2, 2009, at = 3:59 AM, suketu soni wrote:

= Hi,

A point-to-point link type is included twice in a = Router-LSA.

1) As Link Type =3D 1 (p2p), with neighboring = router's RID as Link ID. This happens when the adjacency status is = FULL.

2) As Link Type =3D 3 (stub), with IP subnet address as = Link ID. This happens when the interface state is point-to-point, = regardless of the status of adjacency.

I found out that if a = point-to-point link is used as passive-interface, then adjacency will = not be formed. Hence, link type =3D 1 advertizement will be absent. = However, a link type =3D 3 advertizement of such a link makes it = reachable.

Please share more examples where it helps to advertize = a p2p link type in two ways. My intention is to understand the need for = having two types of advertizements for the same p2p = link.

The two links serve completely = different purposes. The type 1 link is to advertise connectivity to the = other router, i.e., an edge in the SPF graph, while the type 3 link is = to advertise the IP = subnet. 

Thanks,
Acee 
<= div>


Thank you.

Best = wishes
Suketu Soni
One blink is all it takes for the world to = change. One click and MSN India helps you catch up Try it!
OSPF mailing list
=

= --Apple-Mail-5-896705659--