Re: Q on the congestion awareness of routing protocols

Jon Crowcroft <Jon.Crowcroft@cl.cam.ac.uk> Sat, 03 December 2022 10:18 UTC

Return-Path: <Jon.Crowcroft@cl.cam.ac.uk>
X-Original-To: tsv-area@ietfa.amsl.com
Delivered-To: tsv-area@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 4245BC14CE4C; Sat, 3 Dec 2022 02:18:32 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -4.297
X-Spam-Level:
X-Spam-Status: No, score=-4.297 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, RCVD_IN_DNSWL_MED=-2.3, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=cl.cam.ac.uk
Received: from mail.ietf.org ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id y_KOwCoFPEHJ; Sat, 3 Dec 2022 02:18:27 -0800 (PST)
Received: from mta1.cl.cam.ac.uk (mta1.cl.cam.ac.uk [128.232.0.57]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange ECDHE (P-256) server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id F3E03C14CF17; Sat, 3 Dec 2022 02:18:26 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=cl.cam.ac.uk; s=mta3; h=Message-Id:Date:Content-ID:Content-Type: MIME-Version:References:In-reply-to:Subject:cc:To:From:Sender:Reply-To: Content-Transfer-Encoding:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=lqs4afoiHu+vz7gs1GHBi0VmH+chyKBjZ+dWqwV7nkQ=; t=1670062706; x=1670926706; b=TrN3HefZTAwHFmHObLqFpZjMoWFOch5gUgBZ14STv3BQjbm8NwVkTL0QuU6NoDOVfhW2XiRryBU aHUIDcisGyX9VjkG+FHDVpzRKBCykP7RCVxenklJNoBoMMv2naAfs+1ZzFcJP8KZd9TKAd5gygrJ1 QKWmnqhQ+bIaWVgj88dRoE6MP47/X0FH41RqQ87LLJITZewhKchODg10BJvR0mSsXIa4/UaKRx4OF ukmaGfEzkHtmtSSV1FE86GMmPOTV2pq6MPpFIahH5jK3ESYc5axu11OZ1iCgVUOow1ZGV0woa3TAj 6LPK4hgbYbwiMSCnrQOkkE+j00LAFvSKKbxQ==;
Received: from svr-ssh-1.cl.cam.ac.uk ([128.232.102.11]:45770) (dnseec=no) by mta1.cl.cam.ac.uk:587 [128.232.0.57] with esmtp (Exim 4.95) id 1p1PaX-009tgu-Hl (envelope-from <Jon.Crowcroft@cl.cam.ac.uk>); Sat, 03 Dec 2022 10:17:41 +0000
From: Jon Crowcroft <Jon.Crowcroft@cl.cam.ac.uk>
To: Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp>
cc: Jon Crowcroft <jon.crowcroft@cl.cam.ac.uk>, Toerless Eckert <tte@cs.fau.de>, routing-discussion@ietf.org, tsv-area@ietf.org, pim@ietf.org, bier@ietf.org
Subject: Re: Q on the congestion awareness of routing protocols
In-reply-to: <e2527c9c-c7d1-c6b7-a067-e5ccbdc7e997@necom830.hpcl.titech.ac.jp>
References: <Y4ovyV074qa3gLSu@faui48e.informatik.uni-erlangen.de> <CAEeTejLa8sdJVU_2OfTo=ZgWRY-kv_7M=xiR-bLyBEXhSDP=Eg@mail.gmail.com> <e2527c9c-c7d1-c6b7-a067-e5ccbdc7e997@necom830.hpcl.titech.ac.jp>
Comments: In-reply-to Masataka Ohta <mohta@necom830.hpcl.titech.ac.jp> message dated "Sat, 03 Dec 2022 18:36:04 +0900."
MIME-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-ID: <3422344.1670062661.1@svr-ssh-1.cl.cam.ac.uk>
Date: Sat, 03 Dec 2022 10:17:41 +0000
Message-Id: <E1p1PaX-009tgu-Hl@mta1.cl.cam.ac.uk>
Archived-At: <https://mailarchive.ietf.org/arch/msg/tsv-area/hF6X--YWpEe3CYWmQYF6S4IshYE>
X-BeenThere: tsv-area@ietf.org
X-Mailman-Version: 2.1.39
Precedence: list
List-Id: IETF Transport and Services Area Mailing List <tsv-area.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/tsv-area>, <mailto:tsv-area-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/tsv-area/>
List-Post: <mailto:tsv-area@ietf.org>
List-Help: <mailto:tsv-area-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/tsv-area>, <mailto:tsv-area-request@ietf.org?subject=subscribe>
X-List-Received-Date: Sat, 03 Dec 2022 10:18:32 -0000

i suggest reading
https://www.icir.org/floyd/srm.html
plus any of many papers on tcp incast 
> Jon Crowcroft wrote:
> 
> 
>     Gonna say, ironically, one early use of multicast was a proposal to 
> use SRM
>     instead of a mesh of tcp connections for iBGP...so some people do 
> think
>     about scaling control plane traffic in the presence of congestion, 
> some
>     times:-)
> 
> That is a terrible approach, because, even within a link, TCP
> mesh is the way to go against congestion.
> 
> That is, within each link, routers should not rely on link
> multicast to exchange multicast control messages and should
> have TCP mesh between them over which the messages can be
> exchanged reliably even if there is congestion, which is
> what I did in 2001 with SRSVP (Simple RSVP, a stable and
> hierarchical unicast/multicast QoS routing protocol
> without crank back).
> 
>                                         Masataka Ohta
> 
>