Re: [mpls] Clarification on the motivation of draft-xu-spring-islands-connection-over-ip-05

Uma Chunduri <> Mon, 11 April 2016 21:46 UTC

Return-Path: <>
Received: from localhost (localhost []) by (Postfix) with ESMTP id BB17012D16B; Mon, 11 Apr 2016 14:46:35 -0700 (PDT)
X-Virus-Scanned: amavisd-new at
X-Spam-Flag: NO
X-Spam-Score: -4.202
X-Spam-Status: No, score=-4.202 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_MSPIKE_H2=-0.001, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Received: from ([]) by localhost ( []) (amavisd-new, port 10024) with ESMTP id Js95Av0SKn6b; Mon, 11 Apr 2016 14:46:33 -0700 (PDT)
Received: from ( []) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by (Postfix) with ESMTPS id 22FB312B033; Mon, 11 Apr 2016 14:46:33 -0700 (PDT)
X-AuditID: c6180641-f79fa6d0000057a9-e1-570c1b10a345
Received: from (Unknown_Domain []) by (Symantec Mail Security) with SMTP id 32.4A.22441.01B1C075; Mon, 11 Apr 2016 23:45:53 +0200 (CEST)
Received: from ([]) by ([]) with mapi id 14.03.0248.002; Mon, 11 Apr 2016 17:46:31 -0400
From: Uma Chunduri <>
To: Eric C Rosen <>, Xuxiaohu <>, "" <>
Thread-Topic: [mpls] Clarification on the motivation of draft-xu-spring-islands-connection-over-ip-05
Thread-Index: AQHRkR6Kh266HVaFkUy+fRZ9moMOGJ+FZusA///mJkA=
Date: Mon, 11 Apr 2016 21:46:31 +0000
Message-ID: <>
References: <> <> <> <>
In-Reply-To: <>
Accept-Language: en-US
Content-Language: en-US
x-originating-ip: []
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0
X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFupmkeLIzCtJLcpLzFFi42KZXLonSldQmifc4PJ5Lot1Gz4wW9xaupLV 4viF34wWW8+vYnRg8Wg58pbVY8mSn0we15uusgcwR3HZpKTmZJalFunbJXBlLHvzhbWgV6Bi 35ILbA2Mx3m6GDk5JARMJOY/2sICYYtJXLi3nq2LkYtDSOAoo8TJiw+gnOWMEufXNLCDVLEJ 6El8nPoTzBYRyJGY3HcLqIiDg1lAWeLUXRmQsLBAmsScGcdYIErSJW7f/8gGYVtJPH/TzAhi swioSnzvf8gEYvMK+EpMfrmTCWLXY0aJ22/ugiU4BbQl1m35C2YzAl33/dQaMJtZQFzi1pP5 TBBXC0gs2XOeGcIWlXj5+B8rhK0osa9/OjtEvY7Egt2f2CBsbYllC18zQywWlDg58wnLBEax WUjGzkLSMgtJyywkLQsYWVYxcpQWF+TkphsZbmIERtExCTbHHYx7ez0PMQpwMCrx8CqwcocL sSaWFVfmHmKU4GBWEuGtlOQJF+JNSaysSi3Kjy8qzUktPsQozcGiJM7rHfkvTEggPbEkNTs1 tSC1CCbLxMEp1cBYzrKgW/dPUEuP+BptM/ODNlXb2T81T2bIZdbUXLPn7oWIJxIT4jxnbi5c vCRWNtPn6t+D19PubHRRTMp7X7IoPOPE3TPtk4/E/HwcuETrPIujwmaXb2/W7TFWWhtf3sa2 4s4h/mc72uJ3nzombeD85evP+uwnBzbejWx2vJSXlR7P6fb82bz1SizFGYmGWsxFxYkAOKnP 0p4CAAA=
Archived-At: <>
Cc: "" <>
Subject: Re: [mpls] Clarification on the motivation of draft-xu-spring-islands-connection-over-ip-05
X-Mailman-Version: 2.1.17
Precedence: list
List-Id: Multi-Protocol Label Switching WG <>
List-Unsubscribe: <>, <>
List-Archive: <>
List-Post: <>
List-Help: <>
List-Subscribe: <>, <>
X-List-Received-Date: Mon, 11 Apr 2016 21:46:36 -0000

Hi Eric,

Quick  response  In-line [Uma]:

Uma C.

-----Original Message-----
From: mpls [] On Behalf Of Eric C Rosen
Sent: Monday, April 11, 2016 11:51 AM
To: Xuxiaohu;
Subject: Re: [mpls] Clarification on the motivation of draft-xu-spring-islands-connection-over-ip-05

On 4/7/2016 6:39 PM, Xuxiaohu wrote:
> [Xiaohu] The FEC associated the above label L is the /32 or 128/ prefix of node N. When the IGP next-hop towards that FEC is a non-MPLS node, the LSR receiving the above MPLS packet with top label of L is desired to forward that MPLS packet towards node N via an IP-based tunnel. In this case, the node N is the remote peer for that FEC.

Yes, in this case, the tunnel's receive endpoint can be regarded as a remote label distribution peer of the tunnel's  transmit endpoint.

However, in the above case I don't think it is obvious that you want to IP-tunnel the packet to N.  
You might just want to tunnel it around the 
non-MPLS node.   In that case, the tunnel's receive endpoint can still 
be regarded as a remote label distribution peer of the transmit endpoint, but the receive endpoint is not N.

[Uma]:  Sure, this can be done; if at all if there is a shortest path node towards N (supporting MPLS/SR) and if we can tunnel to that node yes, packet can be delivered to N eventually.
               However, this involves (additional computation/adjustment) computation by all the boarder nodes to deliver it to the shortest SR node towards N.
               In that case, actually I would have expected operator to put that additional node Label as the top label instead of N. If the former has to happen operator has to 
               exercise how this should happen through a knob ..(apart from the additional work on the boarder node).

mpls mailing list