[bess] AD Review of draft-ietf-bess-dci-evpn-overlay-05
Alvaro Retana <aretana.ietf@gmail.com> Thu, 18 January 2018 16:08 UTC
Return-Path: <aretana.ietf@gmail.com>
X-Original-To: bess@ietfa.amsl.com
Delivered-To: bess@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id A179612711D; Thu, 18 Jan 2018 08:08:34 -0800 (PST)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -2.698
X-Spam-Level:
X-Spam-Status: No, score=-2.698 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, UNPARSEABLE_RELAY=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 0INBoAvwEqVZ; Thu, 18 Jan 2018 08:08:31 -0800 (PST)
Received: from mail-oi0-x242.google.com (mail-oi0-x242.google.com [IPv6:2607:f8b0:4003:c06::242]) (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 B4AF712711B; Thu, 18 Jan 2018 08:08:28 -0800 (PST)
Received: by mail-oi0-x242.google.com with SMTP id e144so16060715oib.4; Thu, 18 Jan 2018 08:08:28 -0800 (PST)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:mime-version:date:message-id:subject:to:cc; bh=nLcKQHhHQyr+0pfnqoLg85aXtbtNw7bCMXNl0zbL6ow=; b=YKIMiUJycIWd7FsiKN87Mhi3+cS3XGyRv7M6yNBRFwhjKGKM3pLTpCSeZuXJcYTjPM kqZW0A8XBmdfH4TBd76JjE+SFEqvEA4RGjbhWqSczAuzr9fKZX/ALrMbgn7A89ZLFYMb Rf2pNrLJIcBiA2miIOx0HX+A6+Xb+trefVv2dJx5+KO0srhqiS6HuzNOAjDeeqrMoEn8 itPDsf9j70/M5voelsy4sqsOOsnOoXxs5SQ5vYf5h4I3minGL7yKWALG4qRhM6OSnD9d +B6lUisJXyHKp0VgrIK0734Alql36FLyECydz1WsrkaVHbc8+FlXrqX4fk7WDkAdDnx9 WFUw==
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:mime-version:date:message-id:subject:to:cc; bh=nLcKQHhHQyr+0pfnqoLg85aXtbtNw7bCMXNl0zbL6ow=; b=RfA6ZpEj0Ou9nfMPLA0GjZcjfso69bta50ZeN06Lfomiu8ebot2NYX6SaHSpeZa89T /iJYBbT6Bjpzb7dGvsdJWeZqRxZZmHkacXROvSioSPiii3/mol65tfF3M7P9JquEeZks aSs3y+s+9r8JPG6xrmG9ioVkgy8fpg70RHg7AY77gtq1vRBKK6F5rea4TOyx296/1jJf ieQa0cXTxBhnkXhlqqgn35thm4S+VFHWumC5y3m33fABbAN99CrSBUBS93DZlslhKuG3 zI7UjedJme0FdbeudeFTj3spTRsTrSAmBu3UECVRe05rZZ83/GugYDLYZVUDbRnTv1lx B3ew==
X-Gm-Message-State: AKwxyteMKyglj0CimbJG24YIlz2yIodwA54PB40pT7iA54egu15GIlxG ryaKdnx7RI/S7OK8zmZZg/qiMT7B0hoX3oilFfQ=
X-Google-Smtp-Source: ACJfBosXc307PXbSFvzioKUTfKLn5Zy0J4RDwvsHueARBdrOMrUVFyawuZmNy7619JQ73rVmIGwF3B0iWKobOEY2S5E=
X-Received: by 10.202.212.199 with SMTP id l190mr3450152oig.263.1516291707772; Thu, 18 Jan 2018 08:08:27 -0800 (PST)
Received: from 1058052472880 named unknown by gmailapi.google.com with HTTPREST; Thu, 18 Jan 2018 08:08:27 -0800
From: Alvaro Retana <aretana.ietf@gmail.com>
X-Mailer: Airmail (467)
MIME-Version: 1.0
Date: Thu, 18 Jan 2018 08:08:27 -0800
Message-ID: <CAMMESszn8D2_pEgohF_TUdoXk49k8onqf671bwVcLWv6sxJDAw@mail.gmail.com>
To: draft-ietf-bess-dci-evpn-overlay@ietf.org
Cc: bess@ietf.org, bess-chairs@ietf.org, Martin Vigoureux <martin.vigoureux@nokia.com>
Content-Type: multipart/alternative; boundary="001a113de59a9e250705630f2ce0"
Archived-At: <https://mailarchive.ietf.org/arch/msg/bess/rpSun0o4TPdELPaH-rwBBmHKWJg>
Subject: [bess] AD Review of draft-ietf-bess-dci-evpn-overlay-05
X-BeenThere: bess@ietf.org
X-Mailman-Version: 2.1.22
Precedence: list
List-Id: BGP-Enabled ServiceS working group discussion list <bess.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/bess>, <mailto:bess-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/bess/>
List-Post: <mailto:bess@ietf.org>
List-Help: <mailto:bess-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/bess>, <mailto:bess-request@ietf.org?subject=subscribe>
X-List-Received-Date: Thu, 18 Jan 2018 16:08:35 -0000
Dear authors: I just finished reading this document. As with draft-ietf-bess-evpn-overlay, it seems to me that this document is better suited as an Applicability Statement [1] instead of a Technical Specification -- both would result in a Standards Track document. It is hard for me to clearly identify what this document is specifying, vs explaining how to use existing mechanisms (already specified elsewhere) to achieve the DCI. I don't want to dig too deep into this point, but it would be nice if you at least considered refocusing the text. I do have some more comments below. I'll wait for an updated draft before starting the IETF Last Call. Thanks! Alvaro. [1] https://tools.ietf.org/html/rfc2026#section-3.2 Major: M1. I don't feel too good about using Normative Language to describe the requirements (2.1 and 3.1) because the normative part of this document should be the solution itself, not the requirements (which the solution will then solve). As I read the requirements, with the Normative Language in them, there are questions that come up, which wouldn't be there if rfc2119 keywords were not used. M1.1. There's an important use of the words "supported" and "implemented", what do they mean from a Normative point of view? Are you using them from the point of view of the operator implementing something in their network, or the solution (the software feature) including them? How do you Normatively enforce that? Some examples of their use are: "Per-service load balancing MUST be supported. Per-flow load balancing MAY be supported..." (2.1), "The following optimizations MAY be supported..." (2.1), "Multi-homing MUST be supported. Single-active multi-homing with per-service load balancing MUST be implemented. All-active multi-homing, i.e. per-flow load-balancing, SHOULD be implemented as long as the technology deployed in the WAN supports it" (3.1). In summary, I think that the requirements would be better served with non-rfc2119 language. M1.2. The use of "MUST be supported" doesn't stop when talking about the requirements: M1.2.1. In 2.4: "As already discussed, single-active multi-homing, i.e. per-service load-balancing multi-homing MUST be supported in this type of interconnect." Assuming you take off the Normative Language in 2.1, take out "as already discussed"... M1.2.2. In 2.5: "The following features MAY be supported..." I'm assuming "MAY" is used here because the optimizations are optional; saying so would be better as some of the descriptions in the sub-sections include other Normative Language. M1.2.2. In 2.3 an option exists...but in both cases "MUST be supported" is used. As I asked above, what does this mean from the enforcement of the Normative Language point of view? If we think about interoperability, then maybe a more prescriptive sentence would work better. Suggestion: s/the provisioning of the VCID for such PW MUST be supported on the MAC-VRF/the VCID MUST be provisioned... M1.2.3. In 3.2.2./3.3.2: "Single-active multi-homing MUST be supported on the GWs." ... M1.2.4. 3.4.3/3.5.2: "Single-active as well as all-active multi-homing MUST be supported." M2. From 2.5.3: "Individual AC/PW failures MAY be detected by OAM mechanisms." The "MAY" seems to just be stating a fact; s/MAY/may M2.1. The two "MAYs" in the bullets following the "for instance" seem out of place too. If the intent is to just list two possibilities (examples) then the "MAYs" should not be Normative. M3. Security Considerations. Please see my note above about thinking that this document is more appropriate to be an Applicability Statement (than a Technical Specification). The Security Considerations section basically directs the reader to existing work. I would like to see a statement (for the benefit of the security reviewers) along the lines of: "This document defines...as a result there are no new security considerations." Note that considering this document a Technical Specification by definition it means it adds something -- so please focus on that here. M4. References: The reference to draft-ietf-bess-evpn-overlay should be Normative. Minor: P1. The "Conventions and Terminology" (Section 5) should be moved to the front of the document. P2. Please add references to VPLS, EVPN, VXLAN, 802.1q/ag, etc, etc. on first mention. All these technologies are important in understanding the document, but only some are properly referenced later. Ideally, there would be a reference when a mayor technology is mentioned (specially the first time) and when other important features are mentioned and assumed -- for example: in "Even if optimized BGP techniques like RT-constraint are used..." it would be nice to put a reference to RT-constraint. It's all about the completeness of the document... P2.1. In 2.3: "the usual MPLS procedures between GW and WAN Edge router"; a reference here would be nice. P3. Please use the template in rfc8174, instead of the one in rfc2119. P4. In 3.4.1, I can't really parse this text: "Normally each GW will setup one (two) BGP EVPN session(s) to the DC RR(s) and one(two) session(s) to the WAN RR(s)." Specifically the "one (two)" part. P5. The IANA Considerations section is empty [ https://tools.ietf.org/html/rfc8126#section-9.1]. Nits: N1. I know that many of the abbreviations are well-known by now, but please expand as needed, specially in the first few sections to give the readers a better idea of the content. Note that PBB and VPLS are in the "RFC Editor Abbreviations List" [2], but, surprisingly EVPN is not. [Note to self/shepherd: ask the RFC Editor to add EVPN when this document gets to them.] N1.1. Figure 2 includes "EVPN-Ovl", which is not expanded or explained anywhere. I'm guessing this is just a general EVPN-Overlay, but the reader shouldn't have to guess. N2. Section 4 doesn't exist. N3. 3.4.1: "Optionally, different I-ESI values MAY be configured..." "Optionally...MAY" is redundant. [2] https://www.rfc-editor.org/materials/abbrev.expansion.txt
- [bess] AD Review of draft-ietf-bess-dci-evpn-over… Alvaro Retana
- Re: [bess] AD Review of draft-ietf-bess-dci-evpn-… Rabadan, Jorge (Nokia - US/Mountain View)
- Re: [bess] AD Review of draft-ietf-bess-dci-evpn-… Alvaro Retana
- Re: [bess] AD Review of draft-ietf-bess-dci-evpn-… Rabadan, Jorge (Nokia - US/Mountain View)