Re: [Pce] Follow up about my question on the mic

Aijun Wang <wangaijun@tsinghua.org.cn> Tue, 27 July 2021 02:55 UTC

Return-Path: <wangaijun@tsinghua.org.cn>
X-Original-To: pce@ietfa.amsl.com
Delivered-To: pce@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A4C293A1546; Mon, 26 Jul 2021 19:55:09 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -1.898
X-Spam-Level:
X-Spam-Status: No, score=-1.898 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, HTML_MESSAGE=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Received: from mail.ietf.org ([4.31.198.44]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id lRsN3RDeveNO; Mon, 26 Jul 2021 19:55:05 -0700 (PDT)
Received: from mail-m17638.qiye.163.com (mail-m17638.qiye.163.com [59.111.176.38]) (using TLSv1.2 with cipher ADH-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id E01273A1541; Mon, 26 Jul 2021 19:55:02 -0700 (PDT)
Received: from DESKTOP2IOH5QC (unknown [219.142.69.75]) by mail-m17638.qiye.163.com (Hmail) with ESMTPA id 8A79B1C00E6; Tue, 27 Jul 2021 10:54:59 +0800 (CST)
From: "Aijun Wang" <wangaijun@tsinghua.org.cn>
To: "'Mike Koldychev \(mkoldych\)'" <mkoldych=40cisco.com@dmarc.ietf.org>, <draft-ietf-pce-pcep-extension-native-ip@ietf.org>
Cc: <pce@ietf.org>
References: <DM6PR11MB38021A1CCCC2C52CA2DA8B94D3E89@DM6PR11MB3802.namprd11.prod.outlook.com>
In-Reply-To: <DM6PR11MB38021A1CCCC2C52CA2DA8B94D3E89@DM6PR11MB3802.namprd11.prod.outlook.com>
Date: Tue, 27 Jul 2021 10:54:58 +0800
Message-ID: <06fc01d78292$c9b30df0$5d1929d0$@tsinghua.org.cn>
MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="----=_NextPart_000_06FD_01D782D5.D7D73850"
X-Mailer: Microsoft Outlook 16.0
Content-Language: zh-cn
Thread-Index: AQKyElImyex3doVSjRo34cevJ3RDq6mg+3MQ
X-HM-Spam-Status: e1kfGhgUHx5ZQUtXWQgPGg8OCBgUHx5ZQUlOS1dZCBgUCR5ZQVlLVUtZV1 kWDxoPAgseWUFZKDYvK1lXWShZQUpMS0tKN1dZLVlBSVdZDwkaFQgSH1lBWRlLHhpWH0NDGhgeTB pDHRhKVRMBExYaEhckFA4PWVdZFhoPEhUdFFlBWU9LSFVKSktPSEhVS1kG
X-HM-Sender-Digest: e1kMHhlZQR0aFwgeV1kSHx4VD1lBWUc6Kxg6KRw6MT8MUUxDAwoDHSkO CVEKFBZVSlVKTUlMSE5PTktLS01LVTMWGhIXVQwaFRwaEhEOFTsPCBIVHBMOGlUUCRxVGBVFWVdZ EgtZQVlJSkJVSk9JVU1CVUxOWVdZCAFZQUpJTUhPNwY+
X-HM-Tid: 0a7ae5e30a59d993kuws8a79b1c00e6
Archived-At: <https://mailarchive.ietf.org/arch/msg/pce/h9kP1JYEhq-DMeeI-J2HKdUWt7E>
Subject: Re: [Pce] Follow up about my question on the mic
X-BeenThere: pce@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Path Computation Element <pce.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/pce>, <mailto:pce-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/pce/>
List-Post: <mailto:pce@ietf.org>
List-Help: <mailto:pce-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/pce>, <mailto:pce-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 27 Jul 2021 02:55:10 -0000

Hi, Mike:

 

Thanks for your questions. Please see the replies inline.

If you have more questions based on the followings answers, we can discuss
them accordingly.

 

Best Regards

 

Aijun Wang

China Telecom

 

From: pce-bounces@ietf.org <pce-bounces@ietf.org> On Behalf Of Mike
Koldychev (mkoldych)
Sent: Tuesday, July 27, 2021 6:36 AM
To: draft-ietf-pce-pcep-extension-native-ip@ietf.org
Cc: pce@ietf.org
Subject: [Pce] Follow up about my question on the mic

 

Hi Authors,

 

Just following up about my 2 questions during the PCE WG session about
https://datatracker.ietf.org/doc/html/draft-ietf-pce-pcep-extension-native-i
p-14.

 

Question 1: Is every prefix going to be advertised (via the RR) to every
node in the native-ip domain, even if those nodes are never on-path for that
prefix? 

[WAJ] Yes, the behavior of RR is unchanged.

If my understanding is correct, the "BGP peer nodes" (R1 & R7 in Figure 4)
would receive the PPA (Prefixes) and would inject these prefixes into the
RR. The RR would then flood these prefixes (as regular BGP IP routes) to
every single node in the domain (R2, R4, R5, R6) with the next-hop being set
to R1 or R7. Please let me know if my understanding is correct or am I
missing something. So even though R5 and R6 in this example are off-path,
they would receive the prefix route from the RR?

[WAJ] Yes, R5 and R6 will also receive such prefix advertisements via the
normal RR behavior. But on router R5&R6, the route to the BGP nexthop
(R1&R7) is learned from the IGP protocol, not from the EPR(Explicit Peer
Route) Object. Then after the recursive process, the forwarding path on
R5&R6 will be along the normal non-optimal path.

 

Question 2: Have you thought about ECMP/UCMP (Equal/Unequal Cost Multipath)?
How would you implement it in your protocol?

[WAJ] Currently, we consider only the ECMP application. If PCE wants to
deploy multiple ECMP paths between two adjacent nodes, it can send two EPR
Objects to the corresponding PCC, with the "Route Priority" field be set to
the same value.

 

Thanks,

Mike.