Acee - I am not sure what your full intent is. There are a number of statements in the NRP scaling document regarding the use of routing protocols - you selected only one to comment on - not sure why.
The gist of the multiple comments serves to discourage the use of routing protocols as a means of supporting NRP. I support this because I think this is an inappropriate use of routing protocols. Sure, at small scale modest impact might be the result - but I don’t see the point in developing protocol extensions (note that the use of existing MT technology is not the end of the protocol requirements - just the beginning) that only work or are acceptable at small scale. You may disagree - but if so I would appreciate a discussion of the larger questions - not just the one sentence. No - I have not seen your shepherd writeup - it does not seem to be visible on the document status page. Les > -----Original Message----- > From: Acee Lindem <acee.i...@gmail.com> > Sent: Friday, January 19, 2024 11:05 AM > To: Les Ginsberg (ginsberg) <ginsb...@cisco.com> > Cc: Chongfeng Xie <chongfeng....@foxmail.com>; Les Ginsberg (ginsberg) > <ginsb...@cisco.com>; jmh <j...@joelhalpern.com>; TEAS WG > <t...@ietf.org>; lsr <lsr@ietf.org> > Subject: Re: [Lsr] [Teas] Fwd: Working Group Last Call for "Applicability of > IS-IS > Multi-Topology (MT) for Segment Routing based Network Resource Partition > (NRP)" - draft-ietf-lsr-isis-sr-vtn-mt-06 > > Speaking as WG member: > > Hi Les, > > You probably saw my shepherd review of this document. > > > On Jan 11, 2024, at 2:33 AM, Les Ginsberg (ginsberg) <ginsb...@cisco.com> > wrote: > > > > Chongfeng – > > We are at the stage of last call. > > The document has been presented and discussed previously – it is time for > WG members to render their opinions. > > For folks who have actively followed/participated in the discussion, it is > > very > unlikely that we will alter opinions by further discussion. Which means if you > and I have different points of view it is very unlikely that I will alter your > opinion and very unlikely that you will alter mine. > > In that context, I typically do not reply when someone posts their opinion > and it is different than mine. The point of last call is to get the opinions > of WG > members. > > In this case, however, I will respond with some clarifications – not in the > hopes of changing your mind – but only to provide additional clarity as to why > I have the opinion that I do. > > The use of MT in support of NRP – at whatever scale – clearly requires > additional SPF calculations – which is something which is expressly identified > as undesirable in draft-ietf-teas-nrp-scalability. > > draft-ietf-teas-nrp-scalability also states (as you have pointed out) that > “control plane extensions” are seen as undesirable. > > I think this needs to removed or at least softened in the NRP scaling > document. The drawbacks of SPF calculations are greatly exaggerated > (especially if implemented efficiently on today’s CPUs). Furthermore, it would > be hypocritical to say that SPF calculations are to avoided and to then > standardize features such as TI-LFA. > > Thanks, > Acee > > > > > > Having implemented the use of MT for purposes other than supporting the > reserved AFI/SAFI specific topologies specified in RFC 5120, I can tell you > that > there is a significant amount of “control plane work” associated with adding > such support. The fact that no new protocol extensions are required is not the > same as saying no new control plane work is required. I can assure you that > there would be a significant amount of control plane work required. > > So I do see that draft-ietf-lsr-isis-sr-vtn-mt is at odds with > > draft-ietf-teas- > nrp-scalability. > > Thanx for listening. > > Les > > From: Lsr <lsr-boun...@ietf.org> On Behalf Of Chongfeng Xie > > Sent: Wednesday, January 10, 2024 7:41 PM > > To: Les Ginsberg (ginsberg) <ginsberg=40cisco....@dmarc.ietf.org>; jmh > <j...@joelhalpern.com>; Acee Lindem <acee.i...@gmail.com>; TEAS WG > <t...@ietf.org>; lsr <lsr@ietf.org> > > Subject: Re: [Lsr] [Teas] Fwd: Working Group Last Call for "Applicability > > of IS- > IS Multi-Topology (MT) for Segment Routing based Network Resource > Partition (NRP)" - draft-ietf-lsr-isis-sr-vtn-mt-06 > > Hi Les, > > Thanks for your comments. > > This is an informational document which describes the applicability of > existing IS-IS MT mechanisms for building SR based NRPs. All the normative > references are either RFCs or stable WG documents. It is true that some > informative references are individual documents, while they just provide > additional information related to this topic, thus would not impact the > stability > and maturity of the proposed mechanism. > > The text you quoted from draft-ietf-teas-nrp-scalability are about the > considerations when the number of NRP increases, how to minimize the > impact to the routing protocols (e.g. IGP). While as described in the > scalability > considerations section of this document, the benefit and limitation of using > this mechanism for NRP are analyzed, and it also sets the target scenarios of > this mechanism: > > “The mechanism described in this document is considered useful for > network scenarios in which the required number of NRP is small” > > Thus it is clear that this solution is not recommended for network > > scenarios > where the number of required NRP is large. > > Please note section 3 of draft-ietf-teas-nrp-scalability also mentioned > > that: > > “The result of this is that different operators can choose to deploy > > things > at different scales.” > > And > > “In particular, we should be open to the use of approaches that do > > not > require control plane extensions and that can be applied to deployments with > limited scope.” > > According to the above text, we believe the mechanism described in this > document complies to the design principles discussed in draft-ietf-teas-nrp- > scalability and provides a valid solution for building NRPs in a limited > scope. > > Hope this solves your concerns about the maturity and scalability of this > mechanism. > > Best regards, > > Chongfeng > > From: Les Ginsberg \(ginsberg\) > > Date: 2024-01-11 08:21 > > To: Joel Halpern; Acee Lindem; t...@ietf.org; lsr@ietf.org > > Subject: Re: [Lsr] [Teas] Fwd: Working Group Last Call for "Applicability > > of IS- > IS Multi-Topology (MT) for Segment Routing based Network Resource > Partition (NRP)" - draft-ietf-lsr-isis-sr-vtn-mt-06 > > (NOTE: I am replying to Joel’s post rather than the original last call email > because I share some of Joel’s concerns – though my opinion on the merits of > the draft is very different. > > Also, I want to be sure the TEAS WG gets to see this email.) > > I oppose Last Call for draft-ietf-lsr-isis-sr-vtn-mt. > > It is certainly true, as Joel points out, that this draft references many > > drafts > which are not yet RFCs – and in some cases are not even WG documents. > Therefore, it is definitely premature to last call this draft. > > I also want to point out that the direction TEAS WG has moved to > recommends that routing protocols NOT be used as a means of supporting > NRP. > > https://www.ietf.org/archive/id/draft-ietf-teas-nrp-scalability- > 03.html#name-scalabliity-design-principl states: > > “…it is desirable for NRPs to have no more than small impact (zero being > preferred) on the IGP information that is propagated today, and to not > required additional SPF computations beyond those that are already > required.” > > https://www.ietf.org/archive/id/draft-ietf-teas-nrp-scalability- > 03.html#name-scalabliity-design-principl states: > > “The routing protocols (IGP or BGP) do not need to be involved in any of > these points, and it is important to isolate them from these aspects in order > that there is no impact on scaling or stability.” > > Another draft which is referenced is > > https://datatracker.ietf.org/doc/draft- > dong-lsr-sr-enhanced-vpn/ - which is not a WG document and – based on the > recommendations in draft-ietf-teas-nrp-scalability – I would argue that the > IGPs should NOT be extended as proposed in this draft. So if a WG adoption > call were to initiated for draft-dong-lsr-sr-enhanced-vpn, I would oppose it. > > This then puts draft-ietf-lsr-isis-sr-vtn-mt in the position of publishing > information about a solution which the IETF is discouraging. I do not know > why the IETF would want to do this. > > If, despite all of the above, at some point it is judged not premature to > publish this draft, I think the draft should at least include statements > indicating > that this approach is not a recommended deployment solution. > > Les > > From: Lsr <lsr-boun...@ietf.org> On Behalf Of Joel Halpern > > Sent: Wednesday, January 10, 2024 3:22 PM > > To: Acee Lindem <acee.i...@gmail.com>; t...@ietf.org; lsr@ietf.org > > Subject: Re: [Lsr] [Teas] Fwd: Working Group Last Call for "Applicability > > of IS- > IS Multi-Topology (MT) for Segment Routing based Network Resource > Partition (NRP)" - draft-ietf-lsr-isis-sr-vtn-mt-06 > > Given that the documents that provide the basic definitions needed for this > are still active Internet Drafts, it seems premature to last call this > document. > > As a lesser matter, it seems odd that draft-ietf-teas-ietf-network-slices, > > which > defines the terms needed to understand this draft, is an Informative > reference. > > Yours, > > Joel > > PS: I considered not writing this email, as it seems quite reasonable to use > MT to support what I expect NRPs to be. So in principle I think the document > is a good idea. > > On 1/10/2024 6:12 PM, Acee Lindem wrote: > > Note that we are last calling this informational document relating to IS-IS > deployment of NRPs using multi-topology. If you have comments, please send > them to the LSR list. > > Thanks, > > Acee > > > > > > > > Begin forwarded message: > > From: Acee Lindem <acee.i...@gmail.com> > > Subject: Working Group Last Call for "Applicability of IS-IS Multi-Topology > (MT) for Segment Routing based Network Resource Partition (NRP)" - draft- > ietf-lsr-isis-sr-vtn-mt-06 > > Date: January 8, 2024 at 5:50:21 PM EST > > To: Lsr <lsr@ietf.org> > > This begins a two week LSR Working Group last call for the “Applicability > > of > IS-IS Multi-Topology (MT) for Segment Routing based Network Resource > Partition (NRP)”. Please express your support or objection prior to Tuesday, > January 23rd, 2024. > > > > Thanks, > > Acee > > > > > > > > _______________________________________________ > > Teas mailing list > > t...@ietf.org > > https://www.ietf.org/mailman/listinfo/teas _______________________________________________ Lsr mailing list Lsr@ietf.org https://www.ietf.org/mailman/listinfo/lsr
