Re: [spring] Understanding the replication draft

"Joel M. Halpern" <jmh@joelhalpern.com> Wed, 01 July 2020 19:44 UTC

Return-Path: <jmh@joelhalpern.com>
X-Original-To: spring@ietfa.amsl.com
Delivered-To: spring@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 098C13A0CAE for <spring@ietfa.amsl.com>; Wed, 1 Jul 2020 12:44:42 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.098
X-Spam-Level:
X-Spam-Status: No, score=-2.098 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=joelhalpern.com
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 5yPqti-4061d for <spring@ietfa.amsl.com>; Wed, 1 Jul 2020 12:44:40 -0700 (PDT)
Received: from mailb2.tigertech.net (mailb2.tigertech.net [208.80.4.154]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 70F3B3A0CAB for <spring@ietf.org>; Wed, 1 Jul 2020 12:44:40 -0700 (PDT)
Received: from localhost (localhost [127.0.0.1]) by mailb2.tigertech.net (Postfix) with ESMTP id 49xsBJ1nP5z1nvr2; Wed, 1 Jul 2020 12:44:40 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelhalpern.com; s=2.tigertech; t=1593632680; bh=bH7SJYjQ1MDrkHLYHSiFgILhFiepnW16rrhyaL19yB4=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=XFWGqC0X+/dlYS+CTlsQZhtKO4orYXeuCFFfHZUOUYT48ljIP5nZ60lY5n92bLZrK 38434eK4O1W3u23DAP1bQ0MLCoMTB9VLGPubKY0OifOJ/BX9ZnJ1mWTgJGOoAGrRFv fMAG4cnkVyqJ2t2s2hqfZVSilM1W8FAJPgjzpM20=
X-Quarantine-ID: <YFprqjNX1BML>
X-Virus-Scanned: Debian amavisd-new at b2.tigertech.net
Received: from [192.168.128.43] (209-255-163-147.ip.mcleodusa.net [209.255.163.147]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mailb2.tigertech.net (Postfix) with ESMTPSA id 49xsBH3rLrz1ntlm; Wed, 1 Jul 2020 12:44:39 -0700 (PDT)
To: Alexander Vainshtein <Alexander.Vainshtein@rbbn.com>, Robert Raszuk <robert@raszuk.net>, Rishabh Parekh <rishabhp@gmail.com>
Cc: "spring@ietf.org" <spring@ietf.org>
References: <94415742-fc4e-1774-bf96-01eac3672bfb@joelhalpern.com> <CABjMoXYCsXb-iP55PsNWHBG187Lm7-2PXfgD3qRn_aD6ppDuMw@mail.gmail.com> <b3aaaa47-af61-6fc0-1086-bfd59efea061@joelhalpern.com> <CABjMoXY5S1Bx3rQM-0eyJfzh9iOgAZoGshs1wFqebnkVZ++G0w@mail.gmail.com> <CAOj+MMFsjRCgbY1V5idoKmqKR7W5gwM7ui7cp6W12GQm0XEHyQ@mail.gmail.com> <AM0PR03MB4499F08DA8589EAEA4A048C29D6C0@AM0PR03MB4499.eurprd03.prod.outlook.com>
From: "Joel M. Halpern" <jmh@joelhalpern.com>
Message-ID: <7aac7bc7-af63-8073-c66e-0d608dc7b4d7@joelhalpern.com>
Date: Wed, 1 Jul 2020 15:44:37 -0400
User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.9.0
MIME-Version: 1.0
In-Reply-To: <AM0PR03MB4499F08DA8589EAEA4A048C29D6C0@AM0PR03MB4499.eurprd03.prod.outlook.com>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Archived-At: <https://mailarchive.ietf.org/arch/msg/spring/RhKjDu_LYQ90jkby4z7WopFJB8Q>
Subject: Re: [spring] Understanding the replication draft
X-BeenThere: spring@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: "Source Packet Routing in NetworkinG \(SPRING\)" <spring.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/spring>, <mailto:spring-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/spring/>
List-Post: <mailto:spring@ietf.org>
List-Help: <mailto:spring-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/spring>, <mailto:spring-request@ietf.org?subject=subscribe>
X-List-Received-Date: Wed, 01 Jul 2020 19:44:42 -0000

I don't even bind if the binding SID behavior is part of the replication 
SID (with different binding results in different directions).  Which 
would seem to allow multi-stage replication even with requirement A.

Allowing a binding SID after the replication SID seems to require that 
the explicit binding SID, t the replicating node, have different 
meanings for different directions.  Or something??

Yours,
Joel

On 7/1/2020 3:42 PM, Alexander Vainshtein wrote:
> Robert, Rishabh and all,
> I concur with Robert but would like to add that Option A woild 
> effectively eliminate the possibility of building MDTs with more than 
> one level using Replication Segments.
> 
> Which is probably not the intent of the draft.
> 
> My 2c.
> 
> Get Outlook for Android <https://aka.ms/ghei36>
> 
> ------------------------------------------------------------------------
> *From:* spring <spring-bounces@ietf.org> on behalf of Robert Raszuk 
> <robert@raszuk.net>
> *Sent:* Wednesday, July 1, 2020, 22:27
> *To:* Rishabh Parekh
> *Cc:* Joel Halpern Direct; spring@ietf.org
> *Subject:* Re: [spring] Understanding the replication draft
> 
> Hi Rishabh,
> 
>   > Of course, care must be
>  > taken to avoid the "explosion" as you describe it. G-SID-2 has to map
>  > to a unique node; for example, it may be an Anycast-SID that takes
>  > packet to distinct nodes from each of the downstream node, or the
>  > downstream nodes can be border nodes connecting to other segment
>  > routing domains where G-SID-2 resolves to distinct nodes in each
>  > domain.
> 
> I think you are stretching it too thin.
> 
> See even if G-SID-2 is anycast SID you have zero assurance that physical 
> nodes packets will land on would be at all diverse.
> 
> Likewise crossing domains yet providing identical global SID now to be a 
> different node in each such domain to me is not a realistic example.
> 
> I think we have two options:
> 
> A) Firmly state that replication SID MUST be the last one on the stack
> 
> B) Instead of real SID after the replication SID provide a binding SID 
> which locally will be mapped to a different SID list imposed to 
> each replicated flow.
> 
> What is currently in the draft seems to be very counterintuitive and 
> IMHO will result in operational difficulties.
> 
> Thx a lot,
> R.
> 
> 
> 
> ------------------------------------------------------------------------
> Notice: This e-mail together with any attachments may contain 
> information of Ribbon Communications Inc. that is confidential and/or 
> proprietary for the sole use of the intended recipient. Any review, 
> disclosure, reliance or distribution by others or forwarding without 
> express permission is strictly prohibited. If you are not the intended 
> recipient, please notify the sender immediately and then delete all 
> copies, including any attachments.
> ------------------------------------------------------------------------