Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-extensions-11
Peter Psenak <ppsenak@cisco.com> Tue, 06 April 2021 11:54 UTC
Return-Path: <ppsenak@cisco.com>
X-Original-To: lsr@ietfa.amsl.com
Delivered-To: lsr@ietfa.amsl.com
Received: from localhost (localhost [127.0.0.1]) by ietfa.amsl.com (Postfix) with ESMTP id 3E3D63A1E2A; Tue, 6 Apr 2021 04:54:44 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -9.6
X-Spam-Level:
X-Spam-Status: No, score=-9.6 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, NICE_REPLY_A=-0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001, USER_IN_DEF_DKIM_WL=-7.5] autolearn=ham autolearn_force=no
Authentication-Results: ietfa.amsl.com (amavisd-new); dkim=pass (1024-bit key) header.d=cisco.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 xWlAPp2Euwah; Tue, 6 Apr 2021 04:54:41 -0700 (PDT)
Received: from aer-iport-2.cisco.com (aer-iport-2.cisco.com [173.38.203.52]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 85E163A1EA7; Tue, 6 Apr 2021 04:54:33 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=11037; q=dns/txt; s=iport; t=1617710074; x=1618919674; h=subject:to:cc:references:from:message-id:date: mime-version:in-reply-to:content-transfer-encoding; bh=UeW5+VPJBOR3aK8XRepbLehYH+XfK8AnJcpYDH8Hh7o=; b=L1ITBiqrBOz9X+NY0Be0sdMrI9JG6jrwgwpFyqnZbBKSzBy11AQRQ+tl ixdCgX2tSQ0glM41s1sdDmqKeGCxb++rAol1Wksqdp/uTGhLDbcGP7KUf 08xB/kFQJGgsa1nAfAlvOhd1TXds2Uzg4KiLH5HNJg4QcYGjCQGjPKyNg o=;
X-IPAS-Result: A0AXAADESmxglxbLJq1aGwEBAQEBAQEBBQEBARIBAQEDAwEBAUCBPwUBAQELAYMhVgEnEoRziQSIHy0DmmUUgWgLAQEBDygMBAEBhFACgXcmNQgOAgMBAQEDAgMBAQEBAQUBAQECAQYEFAEBAQEBAQEBaIVQDYZEAQEBAwEjDwEFLwQDBAcFCwsOCgICERUCAlcGAQwIAQGCbQGCZiEPqjN3gTKBAYM/AYEYg0GBPgaBDyoBjUtDgUlCgRIBASYMgm8+gmACgRctWYJYgmAEgUsKUhkHPSYBAy8UEFgtRQwmBwEBDQM2GJBSi2GdE4EUgxSDPIYlkwwFBwMfg02KeASFYooqhhyVFYIQiVqSXoUKgVUBNoFbMxoIGxU7gjUBATNPGQ6HH4cMDQmIYoVHPwNnAgYBCQEBAwmLBy2CFgEB
IronPort-HdrOrdr: A9a23:0TfOhavm1ktaBGjteDLQp+Tm7skCP4Mji2hD6mlwRA09T+Wzna mV8Mgz/xnylToXRTUEkdePJKGPTRrnhPlIyKMWOqqvWxSjhXChK5ts4ZCn7zrrHSD/8eA179 YHT4FVDtrsAV9myfvr+QXQKadF/PCr+L2l7N2/815DVgdvApsP0y5YDUKhHlRyVE16A/MCZf +hz+5mgxblRngNdMS8ARA+Lor+jvnGjojvbxJDJzNP0mizpAil4rL7DBSUty12O1hy6Iwv/m Tfnwvy6r/LiZ6G4yXB3Gze5Yk+orHc4+ZEbfbgtuEoMDn2zi6naIN9Mofy3wwdkaWI9Esgls XKrlMGOcl+gkmhBl2dkF/KxxTq1ioo5jvZ7WKgxVHnocD/WVsBerN8ub4=
X-IronPort-Anti-Spam-Filtered: true
X-IronPort-AV: E=Sophos;i="5.81,309,1610409600"; d="scan'208";a="34796242"
Received: from aer-iport-nat.cisco.com (HELO aer-core-3.cisco.com) ([173.38.203.22]) by aer-iport-2.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 06 Apr 2021 11:54:25 +0000
Received: from [10.60.140.52] (ams-ppsenak-nitro3.cisco.com [10.60.140.52]) by aer-core-3.cisco.com (8.15.2/8.15.2) with ESMTP id 136BsOIi001879; Tue, 6 Apr 2021 11:54:24 GMT
To: Alvaro Retana <aretana.ietf@gmail.com>, draft-ietf-lsr-isis-srv6-extensions@ietf.org
Cc: John Scudder <jgs@juniper.net>, "lsr-chairs@ietf.org" <lsr-chairs@ietf.org>, lsr@ietf.org, Christian Hopps <chopps@chopps.org>
References: <CAMMESswF4GiLTRAYeLfhkC4w9tsr2J5YaMNFSG=979Bh2tmULw@mail.gmail.com> <836ca254-1273-7339-4c7d-f92d5e17315f@cisco.com> <CAMMESszNithwE6cGy9pkyb7Zxso=BTqwyO9oza-Ascz-5dU=jg@mail.gmail.com> <cf0a8c57-96f7-2684-8752-887887dc1831@cisco.com> <CAMMESszvHXXZpqQhrqF6MFVvpukf7vt4qLVXHocWa1JAneKXRw@mail.gmail.com>
From: Peter Psenak <ppsenak@cisco.com>
Message-ID: <ceab0774-4837-1cc2-23da-8a6945fbebc4@cisco.com>
Date: Tue, 06 Apr 2021 13:54:24 +0200
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:60.0) Gecko/20100101 Thunderbird/60.9.1
MIME-Version: 1.0
In-Reply-To: <CAMMESszvHXXZpqQhrqF6MFVvpukf7vt4qLVXHocWa1JAneKXRw@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"; format="flowed"
Content-Language: en-US
Content-Transfer-Encoding: 8bit
X-Outbound-SMTP-Client: 10.60.140.52, ams-ppsenak-nitro3.cisco.com
X-Outbound-Node: aer-core-3.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/lsr/HAtgICjP4qB23LKfbyZQigDeQSo>
Subject: Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-extensions-11
X-BeenThere: lsr@ietf.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: Link State Routing Working Group <lsr.ietf.org>
List-Unsubscribe: <https://www.ietf.org/mailman/options/lsr>, <mailto:lsr-request@ietf.org?subject=unsubscribe>
List-Archive: <https://mailarchive.ietf.org/arch/browse/lsr/>
List-Post: <mailto:lsr@ietf.org>
List-Help: <mailto:lsr-request@ietf.org?subject=help>
List-Subscribe: <https://www.ietf.org/mailman/listinfo/lsr>, <mailto:lsr-request@ietf.org?subject=subscribe>
X-List-Received-Date: Tue, 06 Apr 2021 11:54:49 -0000
Hi Alvaro, please see inline (##PP3): On 30/03/2021 19:44, Alvaro Retana wrote: > On March 25, 2021 at 6:03:53 AM, Peter Psenak wrote: > > > Peter: > > Hi! > > I have some comments (see below) -- nothing major. I look forward to -12. > > Thanks! > > Alvaro. > > > > > ... >>>>> Just one high-level comment: It is not clear to me why all the >>>>> behaviors from rfc8986 are not covered in this document. If some are >>>>> not applicable, or are covered elsewhere, please explain in the text. >>>> >>>> ##PP >>>> not all behaviors from rfc8986 are applicable to IGPs. Section 10 >>>> ("Advertising Endpoint Behaviors") lists the ones that are applicable to >>>> ISIS. >>> >>> I understand that -- other readers may not. >> >> ##PP2 >> we defined all behaviors that rfc8986 mentions should be advertised by >> IGP, except the END.T. The END.T was originally defined, but during the >> WGLC it was removed based on WG discussion: >> >> Mailing list discussion: >> Thread1: >> https://mailarchive.ietf.org/arch/msg/lsr/0Bp5DJrRJPvRyzZMZS0P_OE8Y7Q/ >> Thread2: >> https://mailarchive.ietf.org/arch/msg/lsr/nKJbY5f6SHEwVCqqfoXSPidGKXQ/ > > Please just say somewhere that END.T is not included -- no need to > justify in the document. ##PP3 done > > > ... >> 342 A prefix/SRv6 Locator that is advertised by a single node and without >> 343 an A-Flag SHOULD be interpreted as a node specific locator. >> >> [major] "advertised by a single node and without an A-Flag" This is >> equivalent to the current behavior of a prefix being "advertised by a >> single node and without an A-Flag". IOW, you seem to be specifying >> behavior that a node that doesn't implement (or even know about) this >> document is expected to follow. >> >> ##PP2 >> if I remove the "prefix" and only keep the SRv6 Locator, would you be >> fine with it? We are defining SRv6 Locator in this document. > > No. The description throughout this section talks about both prefixes > and locators. It reads as a general specification for all prefixes > (including locators). > > Suggestion (taking onto account the responses below)> > > A prefix/SRv6 Locator that is advertised by a single node and without > an A-Flag is considered node specific. ##PP3 done > > >> [major] Related... What is a "node specific locator"? The A-flag >> functionality could be used in a network that otherwise doesn't >> implement SRv6, so calling it a "locator" doesn't seem right. >> >> ##PP2 >> please see my previous response. >> >> >> [major] "SHOULD be interpreted" Interpreting is not really an >> interoperability-requiring action. Is there anything here resulting >> from the interpretation that requires normative language? >> >> ##PP2 >> what about: >> >> "An SRv6 Locator that is advertised by a single node and without >> an A-Flag is considered as a node specific locator." > > > >> ... >> 349 The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 Locator >> 350 TLV as well as the Prefix Reachability TLVs. When a router >> 351 originates both the Prefix Reachability TLV and the SRv6 Locator TLV >> 352 for a given prefix, and the router is originating the Prefix >> 353 Attribute Flags Sub-TLV in one of the TLVs, the router SHOULD >> 354 advertise identical versions of the Prefix Attribute Flags Sub-TLV in >> 355 both TLVs. >> >> [minor] This paragraph doesn't seem necessary given this text in §5: >> >> In cases where a locator advertisement is received in both a Prefix >> Reachability TLV and an SRv6 Locator TLV, the Prefix Reachability >> advertisement MUST be preferred when installing entries in the >> forwarding plane. >> >> ##PP2 >> above mentioned paragraph does not say anything about the Prefix >> Attribute Flags Sub-TLV present in the advertisement of the same prefix >> in the Locator TLV and Prefix Reachability TLV. So we need to keep it. >> >> >> >> [major] If you decide to keep it... "SHOULD advertise >> identical...Prefix Attribute Flags Sub-TLV" When is it ok to not do >> so? Again, given that the Prefix Reachability TLVs are preferred, >> this statement doesn't seem to matter, or carry interoperability >> weight. s/SHOULD/should >> >> ##PP >> well, not really. The Prefix Attribute Flags Sub-TLV should be the same >> to guarantee the same treatment of both locator and legacy prefix >> advertisements. The fact that the legacy prefix advertisement is >> preferred when installing reachability of the prefix to forwarding does >> not mean the Prefix Attribute Flags Sub-TLV advertised with Locator TLV >> is useless - it can still be used when using Locator for other things - >> e.g. derive SID for TILFA protection, etc. > > Does this mean that having the same sub-TLV is also a consideration > when comparing the locator and legacy advertisements? If so, then > that should also be mentioned in §5. > > >> [] This point is related to Gunter's recent e-mail [1]. >> >> ##PP2 >> the text has been updated to address Gunter's comment as follows: >> >> "The Prefix Attribute Flags Sub-TLV can be carried in the SRv6 >> Locator TLV as well as the Prefix Reachability TLVs. When a router >> originates both the Prefix Reachability TLV and the SRv6 Locator TLV for >> a given prefix, and the router is originating the Prefix Attribute Flags >> Sub-TLV in one of the TLVs, the router SHOULD advertise same flags in >> the Prefix Attribute Flags Sub-TLV in both TLVs. However, unlike TLVs >> 236/237 the X-flag in the Prefix Attributes Flags sub-TLV is valid when >> sent in the SRv6 Locator TLV. The state of the X-flag in the Prefix >> Attributes Flags sub-TLV when included in the Locator TLV MUST match the >> setting of the embedded X-flag in any advertisement of the same prefix >> in TLVs 236/237." > > [nit] s/advertise same flags/advertise the same flags ##PP3 done > > [nit] s/ 236/237 / 236 and 237 > ##PP3 done > [major] "MUST match the setting of the embedded X-flag" > > What if the setting doesn't match? What should the receiver do? ##PP3 Added following: "In case of any inconsistency between the Prefix Attribute Flags advertised in the Locator TLV and in the Prefix Reachability TLV, the ones advertised in Prefix Reachability TLV MUST be preferred". > > By "embedded", you are referring to the X bit inside 236/237, right? ##PP3 yes > To differentiate, please call it "X bit" and add references to > rfc5120/5308. ##PP3 done > > > > ... >> [minor] Please add Figure numbers/names for all packet formats. >> >> ##PP2 >> s that really required? I have never done it in any of RFCs I was editor >> for. > > Required, no...but it is good practice. > > > ... >> 666 9. SRv6 SID Structure Sub-Sub-TLV >> >> [] I don't understand what this sub-sub-TV is used for. Can you >> please explain? Is there a relationship between it and the SID that >> is advertised in the sub-TLVs? For example, I would assume that the >> SID would have the bits that correspond to the argument set to 0 -- >> what if they're not? What is the purpose of this information? [Of >> course, none of the supported behaviors take an ARG...] >> >> ##PP2 >> The SRv6 SID Structure Sub-Sub-TLV indicates the structure of the SID >> associated with it. It can be used by implementation for validation of >> the SID for consistency (e.g. if there is no ARG but there is something >> in the ARG bits, then it can be ignored). They can be signalled via >> BGP-LS to controller/apps that can verify the consistency in the block >> and SID addressing in the domain. Details are outside the scope of this >> draft. > > Can you please add something like that to the draft? I think that for > now (unless other people ask as well) simply saying that the use is > outside the scope should be enough. ##PP3 done > > > ... >> 741 11. Implementation Status >> ... >> 752 Types of SID supported: End, End.X, LAN End.X, END.OP >> >> [] "END.OP" is not defined. Also, the others are not types of SIDs, >> but sub-TLVs. >> >> ##PP2 >> removed END.OP. This section is going to be removed anyway. > > That fact doesn't mean that the information in it can be wrong. If > inaccurate, I would prefer the section not be there at all. ##PP3 I removed the "Implementation Status" section, it would have to be removed later anyway. > > > ... >> 834 12.1.2. Revised sub-TLV table >> ... >> 839 Type 27 135 235 236 237 >> >> 841 1 y y y y y >> 842 2 y y y y y >> 843 3 n y y y y >> 844 4 y y y y y >> 845 5 y n n n n >> 846 6 n y y y y >> 847 11 y y y y y >> 848 12 y y y y y >> 849 32 n y y y y >> >> [major] Because the structure of the registry is changed, this >> document should formally Update rfc7370 (where the current registry >> was defined). >> >> ##PP2 >> I added following text: >> >> " "Sub-TLVs for TLVs 135, 235, >> 236, and 237 (Extended IP reachability, MT IP. Reach, IPv6 IP. Reach, >> and MT IPv6 IP. Reach TLVs)" registry defined in [RFC7370] to section >> §12.1.1." >> >> Would that be sufficient? > > We need the header to include the Updates tag, ##PP3 sorry, I'm not sure I get it, what header and what "Updates tag"? > and something in the > Abstract and Introduction. > > In the Abstract> > This documents updates rfc7370 by modifying an existing registry. ##PP3 done > > > The text in Introduction can be the same, with a reference to §12.1.2. ##PP3 done > > This Section should also ask IANA to add this document as a reference > in the regsitry. ##PP3 done > > > ... >> 906 12.5. Sub-Sub-TLVs for SID Sub-TLVs >> >> 908 This document requests a new IANA registry be created under the IS-IS >> 909 TLV Codepoints Registry to control the assignment of sub-TLV types >> 910 for the SID Sub-TLVs specified in this document - Section 7.2, >> 911 Section 8.1, Section 8.2. The suggested name of the new registry is >> 912 "Sub-Sub-TLVs for SID Sub-TLVs". The registration procedure is >> 913 "Expert Review" as defined in [RFC8126]. The following assignments >> 914 are made by this document: >> >> [minor] In line with the name of other registries; suggestion: >> "Sub-sub-TLVs for sub-TLVs 5, 43 and 44 (SRv6 End SID , SRv6 End.X SID >> and SRv6 LAN End.X SID)". >> >> >> ##PP2 >> I find that confusing as the sub-TLVs 5 is a locator Sub-TLV, while >> Sub-TLVs 43 and 44 are IS reachability sub-TLVs. >> What about: >> >> "Sub-Sub-TLVs for SID Sub-TLVs (SRv6 End SID, SRv6 End.X SID >> and SRv6 LAN End.X SID)" > > Most of the other registries include the number of the TLV. So I > think it would be good to remain consistent. Maybe we should ask the > current DEs: Chris, Hannes and Les. ##PP3 I have updated this based on the discussion with Les. thanks, Peter > > [End] > >
- [Lsr] AD Review of draft-ietf-lsr-isis-srv6-exten… Alvaro Retana
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… bruno.decraene
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… bruno.decraene
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Acee Lindem (acee)
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Alvaro Retana
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Alvaro Retana
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Les Ginsberg (ginsberg)
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Alvaro Retana
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Alvaro Retana
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Peter Psenak
- Re: [Lsr] AD Review of draft-ietf-lsr-isis-srv6-e… Alvaro Retana