Re: [Rift] kicking off the charter discussion
Tony Przygienda <tonysietf@gmail.com> Thu, 11 January 2018 02:50 UTC
Return-Path: <tonysietf@gmail.com>
X-Original-To: routing-discussion@ietfa.amsl.com
Delivered-To: routing-discussion@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 8811D12E741; Wed, 10 Jan 2018 18:50:03 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.699
X-Spam-Level:
X-Spam-Status: No, score=-2.699 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, FREEMAIL_FROM=0.001, HTML_MESSAGE=0.001, RCVD_IN_DNSWL_LOW=-0.7, SPF_PASS=-0.001] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (2048-bit key) header.d=gmail.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 uzNnEf_5FYm9; Wed, 10 Jan 2018 18:50:00 -0800 (PST)
Received: from mail-wm0-x22c.google.com (mail-wm0-x22c.google.com [IPv6:2a00:1450:400c:c09::22c]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 14042126C89; Wed, 10 Jan 2018 18:50:00 -0800 (PST)
Received: by mail-wm0-x22c.google.com with SMTP id 141so2553942wme.3; Wed, 10 Jan 2018 18:49:59 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:in-reply-to:references:from:date:message-id:subject:to :cc; bh=vzm4+xAInc6D8PFQoXWuWsh2jJkoxzvHGDW7QCR+43Y=; b=FyameYVrJjEueWn7kdyYwO3s+rjhHcSTCONTKwfGfDlcemYGyAQ+LNQruKnJD1fMum Fz24eXyXoKJkrjnIVOGFq86HxsABrquUIiainWl8+TkNCgPEHP7JdguIhvqWPr6MKuGQ z6vCv04UcNyLWkobIys4QYnotynXCS5FSzTUJWfmfOMrlkAxekhql9heoZqd76sNbRJp qjygzqgK7nJsxFdeDJbtM5n8Oxkt6LWXitQzbBjWBTiNkcW8wvS2QoYaMmQ7hhU/a2I9 uVaXWdNLReMXTUPu/eQDWjZF1VMsXX9t4Ros6gozYy+OaDaphSh6yXRv95L5YPHZFR6l vOKA==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:in-reply-to:references:from:date :message-id:subject:to:cc; bh=vzm4+xAInc6D8PFQoXWuWsh2jJkoxzvHGDW7QCR+43Y=; b=d64AzT9Ivm0FhUrRE/2n093gfv3UPqvJvOy7MmXZWG0hQ4Eg3tDQJ7E79jpWkVS+WG GKB6hQV+4VfnTX8Kbkw4VW4z2gBPTwO1uu2l4ZJ06IXIph674UpLML25kjvezo6i+BXh h8RP7TQDRiv42ESs5oTGNUtx2gM2eBXZpq+ZwbvPS6WuDqXtIfToCtcCFv9BPdpmTh1G Iixd24sFEcZf+mxvTPxZmlT1DTwGjKLjlznt2DEUJ6YV87f6M1YMRaEFtOWF3d0P2pS/ u9zr3pOcQJaKQGxCc6vc3WwJu990hVzNbHReKJkc1d8Z+QDPZpNFUB13fo/azH53Wv5F 1uBA==
X-Gm-Message-State: AKGB3mKNKDGcdlip/3LxoYssJgPkDnRhy6pcYMmHiffSW/qP102D3SyU co8UWcV4rXnZKpP9/WFzv3Qw82Xjfs2yrrbw9KI=
X-Google-Smtp-Source: ACJfBouqMPlecm0+ekTazEMn98+PQBtjEXo0hXRMXGmqEEkZeWShlF38e8sNjN+8dyVDOJL9dPyXj33hDCxb6N0Zk2s=
X-Received: by 10.80.155.89 with SMTP id a25mr28738459edj.290.1515638998514; Wed, 10 Jan 2018 18:49:58 -0800 (PST)
MIME-Version: 1.0
Received: by 10.80.164.199 with HTTP; Wed, 10 Jan 2018 18:49:18 -0800 (PST)
In-Reply-To: <02e901d38a7a$b761a7b0$2624f710$@gmail.com>
References: <CAMMESswZLjEzNrdoCyox4U6sd51T6Cmin=i7hjoEPUa2NCdTJA@mail.gmail.com> <02e901d38a7a$b761a7b0$2624f710$@gmail.com>
From: Tony Przygienda <tonysietf@gmail.com>
Date: Wed, 10 Jan 2018 18:49:18 -0800
Message-ID: <CA+wi2hO2LgDBAaBOE6B1Xs_oJx3-RNfEv4snC4DXtSy8H=KxhQ@mail.gmail.com>
Subject: Re: [Rift] kicking off the charter discussion
To: Russ White <7riw77@gmail.com>
Cc: Alvaro Retana <aretana.ietf@gmail.com>, routing-discussion@ietf.org, rtgwg@ietf.org
Content-Type: multipart/alternative; boundary="94eb2c1aec781d3eee056277343f"
Archived-At: <https://mailarchive.ietf.org/arch/msg/routing-discussion/gcz2o_t7DIeSoL_BLU0Xr0waX2k>
X-BeenThere: routing-discussion@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: Routing Area General mailing list <routing-discussion.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/routing-discussion>, <mailto:routing-discussion-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/routing-discussion/>
List-Post: <mailto:routing-discussion@ietf.org>
List-Help: <mailto:routing-discussion-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/routing-discussion>, <mailto:routing-discussion-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 11 Jan 2018 02:50:03 -0000
Hey Russ, thanks for chimin' in, inlined below On Wed, Jan 10, 2018 at 5:22 PM, <7riw77@gmail.com> wrote: > > > The Routing in Fat Trees (RIFT) protocol addresses the demands of > > routing in Clos and Fat-Tree networks via a mixture of both link-state > and > > I would tend to say "spine and leaf" here, rather than Clod -- Clos is one > instance of a spine and leaf, but there are others. > Hmm, so it's kind of a broader stroke than that. Based on stubborn demand ;-) we have E-W link support @ each level (but just for failure healing purposes since otherwise blocking on fabric becomes hard to predict) and full leaf-2-leaf routing (and smart people start to observe that this can be used to do e.g. fully meshed leaf levels in a PoD ;-) RIFT _could_ be extended conceptually to support links 'bypassing' levels up, there's a section on that in the draft. I consider it not worth bothering since you either pay by bow-tie routing which is highly undesirable or you start to distribute far more topology information to route optimally which will impact many other requirements negatively. But in a sense, as long there's a compass rose involved RIFT could be conceptually made to work ;-) There's enough more work I have thought through but that would blow up the framework of email. So, the topology right now is something like "ordered lattice with backup horizontal links" if you want but I don't know an easy term for it. In real terms FAT tree or CLOS variations right now. > > > - minimize the amount of routing state held at each topology level, > > It is probably useful to indicate both topology and reachability state > here, as they are two different things. > yes, that is a correct observation. Both are minimized but link failures must lead to auto deaggregation which in RIFT does the minimum reachability info necessary to prevent black-holing but in a sense, yes, it is more information albeit amount of "link topology info" doesn't change. Unless we consider prefixes as being part of topology, I don't think there's an agreement on that. > > > - allow traffic steering and re-routing policies, > > This might be a little underspecified ... I think this should probably > include "using metrics and policy carried within the RIFT control plane." > You can always hijack a path using PCEP or something else, so the > requirement, as stated, just feels a little "weak." > first, to be honest, traffic engineering on the fabrics is a bit of a red herring. PGPs will let you go wild from north and south ;-) to steer your traffic around but yes, they need more thinking and push from real applications. And a protocol's policy is always just acting on protocol info (unless you do time of day thingies or tag redistribution or something ;-) so I don't know what your comment is aiming at precisely. > > > It is important that nodes participating in the protocol should > need only > > very light configuration and should be able to join a network as leaf > nodes > > simply by connecting to the network using default configuration. > > "very light" might be better as "minimal?" It would be nice to have > something with a more definite meaning here, but I’m not certain what. > OK, so the ZTP has been done and is in last review of the authors. In fact it was supposed to be published Monday, it will be probably Friday. If you read it carefully then you'll realize that RIFT can do absolute minimal config but if you mis-cable your topology you may end in ugly situations so we allow optionally a bit more than minimal, what you could call "very light" really. And you can mix ZTP nodes with normal modes, that all works BTW. And RIFT ZTP works actually for whole fabric, not only leafs. We can chat more once the draft is out and you looked @ the diffs. > > > The protocol must support IPv6 and should also support IPv4. > > In terms of carrying reachability for, or in terms of running on top of? > Two different things. > > > Well, RIFT doesn't need ANY addressing really, it just carries "prefixes" around and uses own node IDs and link IDs for everything to allow fabrics without any particular address provisioning. Now, running on UDP forces _some_ kind of addresses but if you look @ the spec it just says "just send back to the same thing you got your LIE unicast on". Well, plus a port ;-) which means we imply something like v4 local/v6 local or something (once we get UDP over MPLS [yeah, the other way round ;-)]) working natively ... And yes, you probably want a loopback to get to the node as well ... On the other hand we don't want to do AF VPN_UCAST or some such thing so I struggle how we could formulate that part of the charter better beside saying "must do v4/v6 reachability to the leafs and optionally fabric nodes" ... So give me next rev of your comments based on this input, pls ... --- tony
- Fwd: [Rift] kicking off the charter discussion Alvaro Retana
- RE: [Rift] kicking off the charter discussion Adrian Farrel
- RE: [Rift] kicking off the charter discussion Alvaro Retana
- RE: [Rift] kicking off the charter discussion 7riw77
- Re: [Rift] kicking off the charter discussion Tony Przygienda