Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising OffsetforFlex-Algorithm
Peter Psenak <ppsenak@cisco.com> Fri, 14 April 2023 14:18 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 4DD0AC1516EB for <lsr@ietfa.amsl.com>; Fri, 14 Apr 2023 07:18:04 -0700 (PDT)
X-Virus-Scanned: amavisd-new at amsl.com
X-Spam-Flag: NO
X-Spam-Score: -14.598
X-Spam-Level:
X-Spam-Status: No, score=-14.598 tagged_above=-999 required=5 tests=[BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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, RCVD_IN_DNSWL_HI=-5, RCVD_IN_ZEN_BLOCKED_OPENDNS=0.001, SPF_NONE=0.001, URIBL_BLOCKED=0.001, URIBL_DBL_BLOCKED_OPENDNS=0.001, URIBL_ZEN_BLOCKED_OPENDNS=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 ([50.223.129.194]) by localhost (ietfa.amsl.com [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id V1_jhSn2dCtO for <lsr@ietfa.amsl.com>; Fri, 14 Apr 2023 07:18:00 -0700 (PDT)
Received: from aer-iport-4.cisco.com (aer-iport-4.cisco.com [173.38.203.54]) (using TLSv1.2 with cipher DHE-RSA-SEED-SHA (128/128 bits)) (No client certificate requested) by ietfa.amsl.com (Postfix) with ESMTPS id 36144C15155A for <lsr@ietf.org>; Fri, 14 Apr 2023 07:17:59 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=cisco.com; i=@cisco.com; l=136438; q=dns/txt; s=iport; t=1681481879; x=1682691479; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=ajN07aYF6ga5x63pufp7C2OfBRPVTmbXHUKZ0d9oqt8=; b=IhyMQRtcCABvJz0c1iDjka/OrRRipQJ8ZRgASmnX6MByQ7GJWkhm44pP oGLgI6Qz4n+sZw5ZBf9b/ubi6oimMitM8PsakRXA31GF0ButmAQ5PMikE +YDUOzjgh29VUaUnwmcs+ibVn6fAn/EhqisyohKgafSyFL3Z/e8iCTfqn A=;
X-IronPort-AV: E=Sophos;i="5.99,197,1677542400"; d="scan'208";a="6987837"
Received: from aer-iport-nat.cisco.com (HELO aer-core-2.cisco.com) ([173.38.203.22]) by aer-iport-4.cisco.com with ESMTP/TLS/DHE-RSA-SEED-SHA; 14 Apr 2023 14:17:56 +0000
Received: from [10.60.140.52] (ams-ppsenak-nitro3.cisco.com [10.60.140.52]) by aer-core-2.cisco.com (8.15.2/8.15.2) with ESMTP id 33EEHtLd028056; Fri, 14 Apr 2023 14:17:55 GMT
Message-ID: <1d557d6f-ec99-84eb-9390-db237b1cd8d9@cisco.com>
Date: Fri, 14 Apr 2023 16:17:55 +0200
MIME-Version: 1.0
User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.9.1
Content-Language: en-US
To: 程伟强 <chengweiqiang@chinamobile.com>, Louis Chan <louisc@juniper.net>, linchangwang <linchangwang.04414@h3c.com>, "'Les Ginsberg (ginsb" <ginsberg@cisco.com>, Acee Lindem <acee.ietf@gmail.com>
Cc: lsr <lsr@ietf.org>, Krzysztof Szarkowicz <kszarkowicz@juniper.net>
References: <MWHPR05MB32312AD47458F4369D21381EDBB89@MWHPR05MB3231.namprd05.prod.outlook.com> <f3530b3b-f091-27b3-aacf-a3cd691cb9ce@cisco.com> <9f456617d3ed4769be02685b8daac4c1@h3c.com> <2bb05328-8a5b-92e6-a0bd-266da8492c0f@cisco.com> <40e2d16ac5464bb19acf343dce22fa0d@h3c.com> <27aca645-0f44-e0a5-ddd6-1ad09650e71f@cisco.com> <CH0PR05MB1027331ABC14E0CC7BE13D5A6DB989@CH0PR05MB10273.namprd05.prod.outlook.com> <16e8b360-3566-11c1-c9d6-39d6ad00178f@cisco.com> <CH0PR05MB102733B612F837AC22B0AA750DB999@CH0PR05MB10273.namprd05.prod.outlook.com> <6b48eee2-3e9b-7d01-03ef-3fc2c2e5ab5d@cisco.com> <CH0PR05MB10273D3BD48DECED88DCBB154DB999@CH0PR05MB10273.namprd05.prod.outlook.com> <ac27c8d a-5bbb-3dfe-80 b0-c78d1de42c96@cisco.com> <051e01d96ebb$e9e0e4f0$bda2aed0$@com> <3 16ef57a-9237-2 6e5-ed90-0935f546f8ef@cisco.com> <052801d96ec5$5a5e1c30$0f1a5490$@com> <ea449bb0-6fae-a1b0-4e22-7569cdfcba30@cisco.com> <2b096439580b007-00011.Richmail.00004090047431215951@chinamobile.com>
From: Peter Psenak <ppsenak@cisco.com>
In-Reply-To: <2b096439580b007-00011.Richmail.00004090047431215951@chinamobile.com>
Content-Type: text/plain; charset="UTF-8"; format="flowed"
Content-Transfer-Encoding: 8bit
X-Outbound-SMTP-Client: 10.60.140.52, ams-ppsenak-nitro3.cisco.com
X-Outbound-Node: aer-core-2.cisco.com
Archived-At: <https://mailarchive.ietf.org/arch/msg/lsr/JaAgI5_OHNKDtJsMw-pcywrgdlE>
Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising OffsetforFlex-Algorithm
X-BeenThere: lsr@ietf.org
X-Mailman-Version: 2.1.39
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: Fri, 14 Apr 2023 14:18:04 -0000
Weiqiang, On 14/04/2023 15:52, 程伟强 wrote: > Hi Peter, > > Emails from Louis, Changwang, and Liyan shows that the requirements are > from multiple companies and their analysis also shows that for > large-scale network with more more algos, existing solution is not enough. > > > There are solid requirements and optimized solutions, why not do it? I appreciate the interest, but I have not seen any evidence that the existing encoding does not work for what is defined today - e.g. regular flex-algo. If you are talking about the "virtaul FA", that is not something that is even defned properly. thanks, Peter > > B.R. > > Weiqiang Cheng > > ----邮件原文---- > 发件人:Peter Psenak <ppsenak@cisco.com> > 收件 > 人:Weiqiang Cheng <chengweiqiang@chinamobile.com>,'Peter Psenak' <ppsenak=40cisco.com@dmarc.ietf.org>,'Louis Chan' <louisc@juniper.net>,'linchangwang' <linchangwang.04414@h3c.com>,"'Les Ginsberg (ginsbe'" <ginsberg@cisco.com>,'Acee Lindem' <acee.ietf@gmail.com> > 抄 > 送: 'lsr' <lsr@ietf.org>,'Krzysztof Szarkowicz' <kszarkowicz@juniper.net> > 发送时间:2023-04-14 19:39:40 > 主题:Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising OffsetforFlex-Algorithm > > Weiqiang, > > On 14/04/2023 13:36, Weiqiang Cheng wrote: > > Hi Peter, > > Your information about the deployment is good. > > It is clear there are two different application scenarios: > > 1. For the operators who only need few algos, the current solution is good enough for them, they just need keep it and don't need to worry about the updates. > > 2. For the operators who need more algos, they have no legacy deployment. The new solutions we talked about are good for them. > > > > Now, we need the new solution for the second scenario. > > here we disagree. The existing encoding works just fine for both. > The fact that it may be optimized, does not mean it is a good idea to do so. > > thanks, > Peter > > > > > B.R. > > Weiqiang Cheng > > > > -----邮件原件----- > > 发件人: Peter Psenak [mailto:ppsenak@cisco.com] > > 发送时间: 2023年4月14日 19:03 > > 收件 > 人: Weiqiang Cheng; 'Peter Psenak'; 'Louis Chan'; 'linchangwang'; 'Les Ginsberg (ginsbe'; 'Acee Lindem' > > 抄送: 'lsr'; 'Krzysztof Szarkowicz' > > 主题: Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > > > > Weiqiang, > > > > On 14/04/2023 12:28, Weiqiang Cheng wrote: > >> Hi Peter, > >> As far as I know, Flex Algo is not really deployed by operators by now, mainly because of the scalability concerns. > > > > I know bunch that deployed it and are happy with it. They needed few > > algos, which is what I consider the right usage of it. > > > > thanks, > > Peter > > > >> In fact, the Luois team and our team did not know each other before. However, we proposed solutions for MPLS-SR and SRv6 respectively almost at the same time. So you can see it is a common problem for those operators who want to deploy FA at scale. > >> > >> As discussion in last few days, my observation is that we've agreed the problem is there. > >> I think it's a good time to address it now.I suggest that We can discuss more on the solutions further, instead of discussing the requirements. > >> > >> B.R. > >> Weiqiang Cheng > >> > >> > >> -----邮件原件----- > >> 发件人: Lsr [mailto:lsr-bounces@ietf.org] 代表 Peter Psenak > >> 发送时间: 2023年4月14日 16:51 > >> 收件人: Louis Chan; linchangwang; 程伟 > 强; Les Ginsberg (ginsbe; Acee Lindem > >> 抄送: lsr; Krzysztof Szarkowicz > >> 主题: Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > >> > >> Louis, > >> > >> On 14/04/2023 10:25, Louis Chan wrote: > >>> Hi Peter, > >>> > >>> I do not think we should divert the focus. It is about efficiency in packing information. > >> > >> trying to change the way the protocol encodes existing data is something > >> that we should not do, unless there is a blocking issue that does not > >> allow protocol to work anymore with existing encoding. You have not > >> provided evidence of that. All the claims so far have been around the > >> lines of implementation efficiency and can be addressed by existing > >> protocol mechanism. > >> > >>> > >>> If some important info is required to pass as "necessary evil", then it should. > >>> > >>> Actually, I am looking forward to applying similar method for other metric or ASLA, proposed by someone, and not necessary by me. And I have seen some drafts are addressing this kind of issues. > e.g. For FA200 and FA201, most link metrics are sharing the same > >> values, but only 5% difference in order to achieve some desired > >> behavior. In this case, we should find a way to pack it efficiently. > >> > >> maybe you need a new version of the protocol to do what you propose. > >> > >> thanks, > >> Peter > >> > >>> > >>> Rgds > >>> Louis > >>> > >>> -----Original Message----- > >>> From: Peter Psenak <ppsenak@cisco.com> > >>> Sent: Friday, April 14, 2023 3:32 PM > >>> To: Louis Chan <louisc@juniper.net>; linchangwang <linchangwang.04414@h3c.com>; 程伟强 <chengweiqiang@chinamobile.com>; Les Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem <acee.ietf@gmail.com> > >>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz <kszarkowicz@juniper.net> > >>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > >>> > >>> [External Email. Be cautious of content] > >>> > >>> > >>> Louis, > >>> > >>> On 14/04/2023 07:38, Louis Chan wrote: > >>>> Hi Peter, > >>>> > >>>> For Adj-sid and additional TE requirement, I am not sure what you refer to. > >>>> TE requirement or metric requirement? If it is metric related, we have ASLA draft to address some TE related problem. > >>>> (To me, to reduce ASLA advertisement is required too.) > >>>> > >>>> What TE problem are you referring to? Could you give an example to illustrate you concern? > >>> > >>> there are many TE attributes flooded for TE purposes, e.g., reserved/unreserved bandwidth (per pool), SRLGs, affinities, ... > >>> > >>> You are picking Ajd-SID, but that is not the only thing that is advertised per link. You may have many SRLGs, many affinities, etc. > >>> > >>> > >>> Peter > >>> > >>>> > >>>> Rgds > >>>> Louis > >>>> > >>>> -----Original Message----- > >>>> From: Peter Psenak <ppsenak@cisco.com> > >>>> Sent: Thursday, April 13, 2023 5:09 PM > >>>> To: Louis Chan <louisc@juniper.net>; linchangwang > >>>> <linchangwang.04414@h3c.com>; 程伟 > 强 <chengweiqiang@chinamobile.com>; Les > >>>> Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem > >>>> <acee.ietf@gmail.com> > >>>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz <kszarkowicz@juniper.net> > >>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>> Offset forFlex-Algorithm > >>>> > >>>> [External Email. Be cautious of content] > >>>> > >>>> > >>>> Loius, > >>>> > >>>> there are many reasons why we need to advertise additional data for adjacency - TE being a major one. You are trying to optimize the Adj-SID only, which is not the major contributor anyway. The problem is not specific to Adj-SID. > >>>> > >>>> In terms of convergence, if you are worried about the flooding speed, there is a draft in progress: > >>>> > >>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-iet > >>>> f-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!B1_2-Ht7ugsG_Wz7Ii0QGroMZyo9 > >>>> HTCDcsgefE_pSNK-2bIfNoekducPbd5X3kQ5eMiRk98Jb_PYYg$ > >>>> > >>>> thanks, > >>>> Peter > >>>> > >>>> > >>>> > >>>> On 13/04/2023 10:52, Louis Chan wrote: > >>>>> Hi Peter/all, > >>>>> > >>>>> Here I do a simple analysis on this scaling issue. > >>>>> > >>>>> 1. Assume a network with these parameters > >>>>> - 20 x Flex-algo > >>>>> - 2 x core nodes with 1,000 links > >>>>> - network diameter with 5 hops > >>>>> > >>>>> 2. Just check out the additional advertisement size from core nodes following ChangWang example. > >>>>> > >>>>> For 1 core node, > >>>>> n x 20 x 1000 > >>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes per core node > >>>>> > >>>>> With 2 core nodes, it is 400KB in total > >>>>> > >>>>> LSP num: 400KB/1500 = 267 lsps, at least > >>>>> > >>>>> 3. About the delivery/flooding rate, from > >>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-ie > >>>>> t > >>>>> f-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!B1_2-Ht7ugsG_Wz7Ii0QGroMZyo > >>>>> 9 HTCDcsgefE_pSNK-2bIfNoekducPbd5X3kQ5eMiRk98Jb_PYYg$ > >>>>>>>> > >>>>> As IS-IS is deployed in greater scale both in the number of nodes in > >>>>> an area and in the number of neighbors per node, the impact of the > >>>>> historic flooding rates becomes more significant. Consider the > >>>>> bringup or failure of a node with 1000 neighbors. This will result <--- 1000 adj links > >>>>> in a minimum of 1000 LSP updates. At typical LSP flooding rates used <--- imply 1000 LSP updates > >>>>> today (33 LSPs/second), it would take 30+ seconds simply to send the <--- 33lsp/s > >>>>> updated LSPs to a given neighbor. Depending on the diameter of the > >>>>> network, achieving a consistent LSDB on all nodes in the network > >>>>> could easily take a minute or more. <--- at least double > >>>>> <<< > >>>>> > >>>>> 267/33 = 8.1 sec > >>>>> > >>>>> > >>>>> With a network diameter of 5, the additional time for delivering the consistent LSDB to all remote nodes = > >>>>> m x 8.1 sec, where 1 < m < 5 due to inefficiency or implementation issue > >>>>> > >>>>> It is likely 16+ sec, according to the above description in that draft. > >>>>> > >>>>> If using offset solution, it is around 0.008sec x 2 = 0.016sec in additional. This number is small. > >>>>> > >>>>> Additional of 16+ sec is significant in global convergence time. > >>>>> > >>>>> 4. This model/example does not include nodes from second layer, which also has 2 x 1,000 adj-sid in the reverse direction. The total number would be estimated bigger than 30+ sec. > >>>>> > >>>>> Should this be improved? > >>>>> > >>>>> 5. Flooding could be in all directions. Larger size of advertisement could delay some important update in busy period. i.e. smaller size in advertisement is better. > >>>>> And I assume this draft with offset would also reduce the refresh requirement. > >>>>> > >>>>> Rgds > >>>>> Louis > >>>>> > >>>>> -----Original Message----- > >>>>> From: Peter Psenak <ppsenak@cisco.com> > >>>>> Sent: Wednesday, April 12, 2023 11:26 PM > >>>>> To: linchangwang <linchangwang.04414@h3c.com>; 程伟强 > >>>>> <chengweiqiang@chinamobile.com>; Louis Chan <louisc@juniper.net>; Les > >>>>> Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem > >>>>> <acee.ietf@gmail.com> > >>>>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz > >>>>> <kszarkowicz@juniper.net> > >>>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>> Offset forFlex-Algorithm > >>>>> > >>>>> [External Email. Be cautious of content] > >>>>> > >>>>> > >>>>> Hi Changwang, > >>>>> > >>>>> please see inline ##PP3: > >>>>> > >>>>> On 12/04/2023 16:46, linchangwang wrote: > >>>>>> Hi Peter, > >>>>>> > >>>>>> > >>>>>> Please see inline [changwang lin]. > >>>>>> > >>>>>>> Changwang, > >>>>>> > >>>>>>> please see inline (##PP2): > >>>>>> > >>>>>> > >>>>>> On 12/04/2023 15:13, linchangwang wrote: > >>>>>>> Hi Peter > >>>>>>> > >>>>>>> Please see inline [changwang lin]. > >>>>>>> > >>>>>>>> We've met the same problem when applying Flex Algo in SRv6 network. > >>>>>>> > >>>>>>> what problem exactly, can you please describe it? > >>>>>>> > >>>>>>> [changwang lin] > >>>>>>> Advertisement size of per Flex-Algo Adj-SID in the network Related > >>>>>>> to F(# of node, # of FA, # of links) For a node with 1,000 links > >>>>>>> and > >>>>>>> 20 Flex-Algo > >>>>>>> n x 20 x 1000 > >>>>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes > >>>>>>> SRv6: If n = 24 bytes, it is 400K+ bytes > >>>>>>> If 500 nodes: > >>>>>>> MPLS-SR:it is 200K*500 = 100000k bytes > >>>>>>> SRv6: it is 400K+ * 500 = 200000k bytes > >>>>>>> If interface mtu=1500, lsp length = 1497 > >>>>>>> LSPs num: > >>>>>>> MPLS-SR:10000k bytes/1497 = 66800 lsps > >>>>>>> SRv6: 20000k bytes/1497 = 160320 lsps > >>>>>>> > >>>>>>> The number of LSPs is too large, and IS-IS needs to periodically > >>>>>>> refresh LSPs, resulting in a decrease in ISIS performance and unstable network operation. > >>>>>> > >>>>>> ##PP2 > >>>>>> above is hardly a realistic estimation. > >>>>>> > >>>>>> In a network with 1k nodes, not every node will have 1k links. > >>>>>> > >>>>>> Advertising large number of LSPs is not caused by Adj-SIDs. > >>>>>> With TE enabled the amount of data flooded per link is larger than > >>>>>> advertisement of the 20 Adj-SID. The problem you are highlighting is > >>>>>> not specific to Adj-SIDs, it's generic. > >>>>>> > >>>>>> LSP refresh time can be set to 18 hours and any reasonable > >>>>>> implementation does not refresh all LSPs at the same time. > >>>>>> > >>>>>> [changwang lin] > >>>>>> This problem exists in actual operator networking, it can be calculated based on an actual network as follows: > >>>>>> One network with 200 nodes > >>>>>> One node with 20 interfaces > >>>>>> One interface with 32 flex algos Each interface is assigned two > >>>>>> types of end. x, one PSP and one non PSP, with each end. x occupying > >>>>>> 30 bytes An nbr tlv with basic bandwidth, EAG, and interface address > >>>>>> is approximately 140 bytes Number of LSPs in the entire network: 140 > >>>>>> * 20 * 32 * 200/1497=12000 LSPs > >>>>>> > >>>>>> The performance of IGP has always been affected by the size of the > >>>>>> entire network's LSDB, and even if the periodic flooding time is reduced, there will still be convergence issues. > >>>>> > >>>>> ##PP3 > >>>>> I don't see any relationship between the convergence and the fact that you have to advertise 20 ADJ-SIDs per link. If there is one, it's an implementation problem. > >>>>> > >>>>> > >>>>>> > >>>>>>> > >>>>>>> So we need to optimize on the control surface to save LSP space. > >>>>>> > >>>>>> ##PP2 > >>>>>> with all the respect, I don't agree. The problem as you described it > >>>>>> does not exist. > >>>>>> [changwang lin] > >>>>>> In the actual deployment of MPLS-SR and SRv6 networks, as the number > >>>>>> of flex algos and interfaces increases, the space occupied by adj-sids becomes larger and larger. > >>>>>> This is the actual problem when deploying flex algos. > >>>>> > >>>>> ##PP3 > >>>>> I don't see any protocol problem. > >>>>> > >>>>> > >>>>>> > >>>>>>> Through the optimization notification mechanism mentioned in these > >>>>>>> two documents, we have greatly saved LSP space for IS-IS and improved the performance of IS-IS flex algo in large-scale networking. > >>>>>>> At the same time, through the VFA mechanism, in other non flex algo application scenarios, > >>>>>>> such as network slicing scenarios, the LSP space of IS-IS can > >>>>>>> also be saved > >>>>>> > >>>>>> ##PP2 > >>>>>> it seems to me you are trying to fix the implementation problem with > >>>>>> the protocol changes, which is never a good idea. > >>>>>> > >>>>>> [changwang lin] > >>>>>> In actual deployment, a flex algo corresponds to the SLA > >>>>>> requirements of a service, such as different bandwidth guarantees, > >>>>>> 128 flex algos can correspond to 128 service requirements. > >>>>>> When the flex algo specification increases, the corresponding number of LSPs rapidly increases, making it impossible to deploy large flex algo applications. > >>>>>> And the mechanism of this draft can greatly improve the space utilization of LSP.. > >>>>> > >>>>> ##PP3 > >>>>> I appreciate your effort, but I don't believe the proposed compression is needed, nor that it addresses the problem you have. > >>>>> > >>>>> The amount of data being flooded per adjacency may potentially be large and Adj-SIDs only represent a fraction of it - even with 32 Adj-SIDs per link you are not hitting any protocol limitation. > >>>>> > >>>>> thanks, > >>>>> Peter > >>>>> > >>>>> > >>>>>> > >>>>>> thanks, > >>>>>> Changwang lin > >>>>>> > >>>>>> > >>>>>> > >>>>>>> thanks, > >>>>>>> Peter > >>>>>> > >>>>>>> > >>>>>>> > >>>>>>> thanks, > >>>>>>> Changwang lin > >>>>>>> > >>>>>>> > >>>>>>> -----Original Message----- > >>>>>>> From: Lsr [mailto:lsr-bounces@ietf.org] On Behalf Of Peter Psenak > >>>>>>> Sent: Wednesday, April 12, 2023 7:10 PM > >>>>>>> To: 程伟强; Louis Chan; Les Ginsberg (ginsbe; Acee Lindem > >>>>>>> Cc: lsr; Krzysztof Szarkowicz > >>>>>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>> Offset forFlex-Algorithm > >>>>>>> > >>>>>>> Weiqiang, > >>>>>>> > >>>>>>> please see inline (##PP): > >>>>>>> > >>>>>>> On 12/04/2023 12:05, 程伟强 wrote: > >>>>>>>> Hi Louis and Les, > >>>>>>>> > >>>>>>>> > >>>>>>>> My two cents from operator perspective. > >>>>>>>> > >>>>>>>> > >>>>>>>> We've met the same problem when applying Flex Algo in SRv6 network. > >>>>>>> > >>>>>>> what problem exactly, can you please describe it? > >>>>>>> > >>>>>>> [changwang lin] > >>>>>>> Advertisement size of per Flex-Algo Adj-SID in the network Related > >>>>>>> to F(# of node, # of FA, # of links) For a node with 1,000 links > >>>>>>> and > >>>>>>> 20 Flex-Algo > >>>>>>> n x 20 x 1000 > >>>>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes > >>>>>>> SRv6: If n = 24 bytes, it is 400K+ bytes > >>>>>>> If 500 nodes: > >>>>>>> MPLS-SR:it is 200K*500 = 100000k bytes > >>>>>>> SRv6: it is 400K+ * 500 = 200000k bytes > >>>>>>> If interface mtu=1500, lsp length = 1497 > >>>>>>> LSP num: > >>>>>>> MPLS-SR:10000k bytes/1497 = 66800 lsps > >>>>>>> SRv6: 20000k bytes/1497 = 160320 lsps > >>>>>>> > >>>>>>> The number of LSPs is too large, and IS-IS needs to periodically > >>>>>>> refresh LSPs, resulting in a decrease in ISIS performance and unstable network operation. > >>>>>>> > >>>>>>> So we need to optimize on the control surface to save LSP space. > >>>>>>> Through the optimization notification mechanism mentioned in these > >>>>>>> two documents, we have greatly saved LSP space for IS-IS and improved the performance of IS-IS flex algo in large-scale networking. > >>>>>>> At the same time, through the VFA mechanism, in other non flex algo application scenarios, > >>>>>>> such as network slicing scenarios, the LSP space of IS-IS can > >>>>>>> also be saved > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> As the number of slices and the scale of the network increases, > >>>>>>>> the convergence issue which is caused by SIDs advertising and > >>>>>>>> flooding becomes more and more serious. > >>>>>>>> > >>>>>>>> > >>>>>>>> Due to the problem, it is impossible to apply Flex-Algo in the > >>>>>>>> large network, such as the network with more than 1000 routers. > >>>>>>> > >>>>>>> flex-algo has been successfully deployed in a networks that have > >>>>>>> more that 1k nodes. > >>>>>>> > >>>>>>> Maybe you want deploy the flex-algo for something that it was not > >>>>>>> designed for. > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> I believe Louis'draft provides a good idea to resolve this problem. > >>>>>>>> Similar solution for SRv6 SIDs is described in another draft. > >>>>>>> > >>>>>>> Again, what problem exactly? > >>>>>>> > >>>>>>> From what I see the drafts tries to pack algo SIDs to save > >>>>>>> space in LSP. I don't see how it helps to to deploy flex-algo in a > >>>>>>> large scale network. > >>>>>>> > >>>>>>> thanks, > >>>>>>> Peter > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> About the SIDs assignment, I think it is better to have a > >>>>>>>> scheduled assignment than a random assignment as Les mentioned. > >>>>>>>> > >>>>>>>> > >>>>>>>> [1] > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft > >>>>>>>> - > >>>>>>>> c > >>>>>>>> heng-lsr-isis-srv6-sid-block/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrt > >>>>>>>> c j Gl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kmvLCcctw$ > >>>>>>>> <https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draf > >>>>>>>> t > >>>>>>>> - > >>>>>>>> cheng-lsr-isis-srv6-sid-block/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMr > >>>>>>>> t c jGl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kmvLCcctw$ > > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> Thanks, > >>>>>>>> > >>>>>>>> Weiqiang Cheng > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> ----邮件原文---- > >>>>>>>> *发件 > 人:*Louis Chan <louisc=40juniper.net@dmarc.ietf.org> > >>>>>>>> *收件 > >>>>>>>> 人:*"Les Ginsberg (ginsberg)" <ginsberg@cisco.com>,Acee Lindem <acee.ietf@gmail.com> > >>>>>>>> *抄 送: > >>>>>>>> *lsr <lsr@ietf.org>,Krzysztof Szarkowicz <kszarkowicz@juniper.net>,Weiqiang Cheng <chengweiqiang@chinamobile.com> > >>>>>>>> *发送时间:*2023-04-12 10:45:56 > >>>>>>>> *主题:*Re: [Lsr] IETF- > >>>>>>>> 116 LSR - IGP extensions for Advertising Offset > >>>>>>>> forFlex-Algorithm > >>>>>>>> > >>>>>>>> Hi Les, > >>>>>>>> > >>>>>>>> Thanks for the prompt reply. Please see inline for clarification [lc2]. > >>>>>>>> > >>>>>>>> /Louis > >>>>>>>> > >>>>>>>> *From:* Les Ginsberg (ginsberg) <ginsberg@cisco.com> > >>>>>>>> *Sent:* Tuesday, April 11, 2023 11:03 PM > >>>>>>>> *To:* Louis Chan <louisc@juniper.net>; Acee Lindem <acee.ietf@gmail.com> > >>>>>>>> *Cc:* lsr <lsr@ietf.org>; Krzysztof Szarkowicz > >>>>>>>> <kszarkowicz@juniper.net>; Weiqiang Cheng > >>>>>>>> <chengweiqiang@chinamobile.com> > >>>>>>>> *Subject:* RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for Flex-Algorithm > >>>>>>>> > >>>>>>>> *[External Email. Be cautious of content]* > >>>>>>>> > >>>>>>>> Louis - > >>>>>>>> > >>>>>>>> Please see inline. > >>>>>>>> > >>>>>>>> > -----Original Message----- > >>>>>>>> > >>>>>>>> > From: Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > Sent: Monday, April 10, 2023 11:01 PM > >>>>>>>> > >>>>>>>> > To: Les Ginsberg (ginsberg) <ginsberg@cisco.com > >>>>>>>> <mailto:ginsberg@cisco.com>>; Acee Lindem > >>>>>>>> > >>>>>>>> > <acee.ietf@gmail.com <mailto:acee.ietf@gmail.com>> > >>>>>>>> > >>>>>>>> > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>>; Krzysztof > >>>>>>>> Szarkowicz <kszarkowicz@juniper.net > >>>>>>>> <mailto:kszarkowicz@juniper.net>>; > >>>>>>>> > >>>>>>>> > Weiqiang Cheng <chengweiqiang@chinamobile.com > >>>>>>>> <mailto:chengweiqiang@chinamobile.com>> > >>>>>>>> > >>>>>>>> > Subject: RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for > >>>>>>>> > >>>>>>>> > Flex-Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Hi Les, > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Thanks for your questions. Please see inline [lc] below. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > /Louis > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > -----Original Message----- > >>>>>>>> > >>>>>>>> > From: Les Ginsberg (ginsberg) <ginsberg@cisco.com > >>>>>>>> <mailto:ginsberg@cisco.com>> > >>>>>>>> > >>>>>>>> > Sent: Saturday, April 8, 2023 7:34 AM > >>>>>>>> > >>>>>>>> > To: Acee Lindem <acee.ietf@gmail.com > >>>>>>>> <mailto:acee.ietf@gmail.com>>; Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>> > >>>>>>>> > >>>>>>>> > Subject: RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for > >>>>>>>> > >>>>>>>> > Flex-Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [External Email. Be cautious of content] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > OK - since Acee opened the door - here are some > >>>>>>>> comments from me - > >>>>>>>> > >>>>>>>> > starting with the most important. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > (BTW - I still have limited enthusiasm for this draft.) > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 1)The proposal places some restrictions on how operators > >>>>>>>> provision their > >>>>>>>> > >>>>>>>> > network in terms of assigning SIDs and reserving space > >>>>>>>> for future > >>>>>>>> > >>>>>>>> > assignments. > >>>>>>>> > >>>>>>>> > If operators do not use compatible assignment schemes, then this > >>>>>>>> will never > >>>>>>>> > >>>>>>>> > get deployed. It is therefore not enough to come with a nice idea > >>>>>>>> - you must > >>>>>>>> > >>>>>>>> > have some enthusiasm from the operator community. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] If the operator only wants to deploy flex-algo, there is no > >>>>>>>> change in their > >>>>>>>> > >>>>>>>> > Node-sid numbering scheme. For the Adj-sid, these are local > >>>>>>>> labels with local > >>>>>>>> > >>>>>>>> > significant only, and there is no need for any special planning > >>>>>>>> for Adj-sid, > >>>>>>>> > >>>>>>>> > unless you are suggesting they want to make fixed assignment of > >>>>>>>> Adj-sid > >>>>>>>> > >>>>>>>> > label for each link. Even with fixed, the proposed draft has > >>>>>>>> benefit on that. I > >>>>>>>> > >>>>>>>> > will explain later. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] Let's discuss this in the context of prefix-sids - the same > >>>>>>>> applies to adj-sids. > >>>>>>>> > >>>>>>>> Today (i.e., in the absence of your proposal) an operator is free to > >>>>>>>> assign any label within the SRGB for a given prefix/algo pair so > >>>>>>>> long as it is not assigned to some other prefix/algo context. > >>>>>>>> > >>>>>>>> Your proposal places some new restrictions. Now, for a given > >>>>>>>> flex-algo, whenever an operator assigns a given label for a prefix > >>>>>>>> in Algo 0 (call it Label-A0), they must guarantee that > >>>>>>>> "Label-A0+offset" for an advertised flex-algo specific offset is > >>>>>>>> available to be assigned for the prefix/flex-algo pair - and this > >>>>>>>> must be true for all prefixes advertised in algo 0. > >>>>>>>> > >>>>>>>> This is certainly possible to do, but is not guaranteed to be the > >>>>>>>> case in current deployments. > >>>>>>>> > >>>>>>>> For example - and this is only an example...today an operator might > >>>>>>>> utilize a provisioning tool to assign prefix-sids for all supported > >>>>>>>> algorithms on all nodes in the network. > >>>>>>>> > >>>>>>>> To do this, the tool might maintain a database of assigned labels. > >>>>>>>> When provisioning a new node/prefix/algorithm, the logic in the tool > >>>>>>>> might simply take the next available label in the database. > >>>>>>>> > >>>>>>>> The result of this would not be consistent with the requirements of > >>>>>>>> your draft. > >>>>>>>> > >>>>>>>> Which is why I say in order to deploy the extension you propose, > >>>>>>>> such an operator would have to modify its provisioning tool. > >>>>>>>> > >>>>>>>> [lc2] There might be some misunderstanding of our proposal. Let me > >>>>>>>> give some examples. > >>>>>>>> > >>>>>>>> Case 1: Flex-Algo only > >>>>>>>> > >>>>>>>> Prefix offset advertisement: “no” > >>>>>>>> > >>>>>>>> Adj-sid offset advertisement: yes > >>>>>>>> > >>>>>>>> In slide 8’s example, FA129 is using label “402001”, and the > >>>>>>>> advertisement of this label is using existing methods. > >>>>>>>> > >>>>>>>> e.g. SRGB = 400000-460000 > >>>>>>>> > >>>>>>>> FA129: index 2001 (preferred value), or one can choose > >>>>>>>> 111, > >>>>>>>> 222 > >>>>>>>> > >>>>>>>> FA130 (new): index 3001 (preferred value), or 333, 4444 > >>>>>>>> > >>>>>>>> This does not change how the operator to assign label for prefix-sid > >>>>>>>> with their current method. Any index/label could be used for FA > >>>>>>>> prefix within SRGB. > >>>>>>>> > >>>>>>>> The only change is the Adj-sid label allocation, but this “mostly” > >>>>>>>> is only “local” to one node. There is no effect on global label > >>>>>>>> allocation. > >>>>>>>> > >>>>>>>> This draft will be compatible to what operators are doing today. > >>>>>>>> > >>>>>>>> Case 2: VFA only > >>>>>>>> > >>>>>>>> Prefix offset advertisement: yes > >>>>>>>> > >>>>>>>> Adj-sid offset advertisement: yes > >>>>>>>> > >>>>>>>> I agree, with VFA, there would be impact to global allocation to > >>>>>>>> node-sid/prefix-sid. But VFA is a totally new concept. No one has > >>>>>>>> deployed that yet. > >>>>>>>> > >>>>>>>> There is no impact to operators which stick to deploy only Flex-algo. > >>>>>>>> > >>>>>>>> Other case: Flex-Algo w/o Adj-sid offset > >>>>>>>> > >>>>>>>> Continue the example of Case#1 above > >>>>>>>> > >>>>>>>> Another FA131 is added, but no Adj-sid offset is > >>>>>>>> advertised > >>>>>>>> > >>>>>>>> The question would be > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Either allow this configuration, and FA131 will fallback using > >>>>>>>> Algo 0’s adj-sid > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Or, disallow this configuration > >>>>>>>> > >>>>>>>> I tend to “allow” such configuration with mix of FA129, FA130 (with > >>>>>>>> adj-sid offset) and FA131 (w/o adj-sid offset) > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> Could this be done? Sure. > >>>>>>>> > >>>>>>>> Do operators want to do this? I do not know. > >>>>>>>> > >>>>>>>> But since this would be necessary in order to use your proposed > >>>>>>>> extension, it is necessary to gauge operator enthusiasm for making > >>>>>>>> such changes in order to know whether there is any point in > >>>>>>>> proceeding with your proposal. > >>>>>>>> > >>>>>>>> > In slide 8 of the below presentation > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-__;!!NEt6yMaO-gk!EX4RtSVg7I0j > >>>>>>>> O > >>>>>>>> 4 > >>>>>>>> M9ZMrtcjGl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1knGgpMXww$ > >>>>>>>> <https://urldefense.com/v3/__https:/datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-igp-adv-offset-01__;!!NEt6yMa > >>>>>>>> O > >>>>>>>> - > >>>>>>>> gk!Bl7Swe9ql9VT0qGkD6FoZZzTWT2fmIx55eSncdmMgoCJetJ5-80micuqnqk79ye > >>>>>>>> w > >>>>>>>> G > >>>>>>>> B-BleOfrYpSjfI$> > >>>>>>>> > >>>>>>>> > igp-adv-offset-01 > >>>>>>>> > >>>>>>>> <https://urldefense.com/v3/__https:/datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-igp-adv-offset-01__;!!NEt6yMa > >>>>>>>> O > >>>>>>>> - > >>>>>>>> gk!Bl7Swe9ql9VT0qGkD6FoZZzTWT2fmIx55eSncdmMgoCJetJ5-80micuqnqk79ye > >>>>>>>> w > >>>>>>>> G > >>>>>>>> B-BleOfrYpSjfI$> > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > FA129 is a prefix-sid (400201) allocated by operator, and it can > >>>>>>>> be any label. > >>>>>>>> > >>>>>>>> > There is no connection to how Adj-sid is derived. > >>>>>>>> > >>>>>>>> > Per Flex-Algo adj-sid assignment is not affecting > >>>>>>>> network wide label > >>>>>>>> > >>>>>>>> > assignment from operation perspective. Each node could have > >>>>>>>> different local > >>>>>>>> > >>>>>>>> > block for such adj-sid assignment. One might need to estimate > >>>>>>>> total possible > >>>>>>>> > >>>>>>>> > number of link in one chassis for such allocation, or it could be > >>>>>>>> estimated by > >>>>>>>> > >>>>>>>> > OS software itself. I also mentioned in the session, if there is > >>>>>>>> 100 x FA with > >>>>>>>> > >>>>>>>> > 1000 links (high end), it is only 100k labels. Is it difficult to > >>>>>>>> allocate such. > >>>>>>>> > >>>>>>>> [LES:] Your proposal does not reduce the number of labels which need > >>>>>>>> to be "allocated" and installed in forwarding, it only reduces the > >>>>>>>> number of bytes used to advertise this information in LSPs/LSAs. > >>>>>>>> > >>>>>>>> [lc2] You are correct. > >>>>>>>> > >>>>>>>> I think, at the same time, it helps reducing time for global > >>>>>>>> convergence since the advertisement size is smaller, especially in > >>>>>>>> network with long diameter with multi-hops. > >>>>>>>> > >>>>>>>> Also, in > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft > >>>>>>>> - > >>>>>>>> ietf-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtc > >>>>>>>> j Gl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kl_1f1RjQ$ > >>>>>>>> > >>>>>>>> <https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draf > >>>>>>>> t > >>>>>>>> - > >>>>>>>> ietf-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtc > >>>>>>>> j G l2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kl_1f1RjQ$ > > >>>>>>>> (which you participated in) > >>>>>>>> > >>>>>>>> >>> > >>>>>>>> > >>>>>>>> As IS-IS is deployed in greater scale both in the > >>>>>>>> number of nodes in > >>>>>>>> > >>>>>>>> an area and in the number of neighbors per node, the > >>>>>>>> impact of the > >>>>>>>> > >>>>>>>> historic flooding rates becomes more significant. > >>>>>>>> Consider the > >>>>>>>> > >>>>>>>> bringup or failure of a node with 1000 neighbors. > >>>>>>>> This will result > >>>>>>>> > >>>>>>>> in a minimum of 1000 LSP updates. At typical LSP flooding rates > >>>>>>>> used > >>>>>>>> > >>>>>>>> today (33 LSPs/second), it would take 30+ seconds > >>>>>>>> simply to send the > >>>>>>>> > >>>>>>>> updated LSPs to a given neighbor. Depending on the > >>>>>>>> diameter of the > >>>>>>>> > >>>>>>>> network, achieving a consistent LSDB on all nodes in > >>>>>>>> the network > >>>>>>>> > >>>>>>>> could easily take a minute or more. > >>>>>>>> > >>>>>>>> <<< > >>>>>>>> > >>>>>>>> This proposed draft will certainly help. > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > So, this is why I do not understand your question in full. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If the operator plans to use VFA, that would be a different > >>>>>>>> discussion. VFA, > >>>>>>>> > >>>>>>>> > today, does not exist in deployment. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] My comments here have nothing to do with VFA. > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Have you discussed this idea with any operators? > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] I include Wei-qiang from China mobile in this thread. He has > >>>>>>>> shown his > >>>>>>>> > >>>>>>>> > need on this kind of solution. Maybe, he could give his > >>>>>>>> perspective here. [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If so, what has been their response? > >>>>>>>> > >>>>>>>> > If they are open to the idea, how might they migrate from their > >>>>>>>> existing > >>>>>>>> > >>>>>>>> > assignment schemes to an assignment scheme compatible > >>>>>>>> with the > >>>>>>>> > >>>>>>>> > proposal? > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > These are questions that need to be answered before considering > >>>>>>>> this idea. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] In slide 8, if you see these label numbers > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Prefix-sid: 400001, 402001, 406001, 407001 > >>>>>>>> > >>>>>>>> > Adj-sid: 32, 2032, 6032, 7032 > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > From operator perspective or troubleshooting perspective, value > >>>>>>>> xxx001 > >>>>>>>> > >>>>>>>> > represent the same node, and value x032 represent the > >>>>>>>> same link. This > >>>>>>>> > >>>>>>>> > makes things more organized and easier to understand. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If all are random labels, I do not see any benefit at all. > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> [LES:] I am not commenting on whether the label assignment scheme > >>>>>>>> you propose is better or worse than any other. > >>>>>>>> > >>>>>>>> I am only pointing out that you are imposing new restrictions on how > >>>>>>>> labels are allocated. > >>>>>>>> > >>>>>>>> As you are not in charge of how operators provision their networks > >>>>>>>> (nor am I), it is presumptuous of you to think that simply because > >>>>>>>> you think this is a better way to do things that operators will be > >>>>>>>> happy to modify their existing networks to conform to your proposed > >>>>>>>> restrictions. > >>>>>>>> > >>>>>>>> This isn’t academia - you need to vet this with the operator community. > >>>>>>>> > >>>>>>>> [lc2] Please refer to the examples at the top. The picture should be > >>>>>>>> clear by now. There is no restriction to what is deployed > >>>>>>>> today. [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 2)Section 5 Compatibilty > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > There is no "compatibility" with legacy nodes - because all nodes > >>>>>>>> in the > >>>>>>>> > >>>>>>>> > network have to have a consistent understanding of what SID is > >>>>>>>> assigned to a > >>>>>>>> > >>>>>>>> > given context (for prefixes and adjacencies) since they might > >>>>>>>> need to install > >>>>>>>> > >>>>>>>> > forwarding entries for that context. > >>>>>>>> > >>>>>>>> > I do not see any point in deploying this until all nodes support > >>>>>>>> it. If you did do > >>>>>>>> > >>>>>>>> > so, you would need to advertise old and new forms - > >>>>>>>> which does the > >>>>>>>> > >>>>>>>> > opposite of what you are trying to achieve. Instead of reducing > >>>>>>>> LSP space > >>>>>>>> > >>>>>>>> > used you would increase it. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] If the operator just plans to use only Flex-Algo, and no > >>>>>>>> VFA, it should be > >>>>>>>> > >>>>>>>> > compatible with legacy implementation. If legacy nodes do not > >>>>>>>> understand > >>>>>>>> > >>>>>>>> > adj-sid offset notation, these nodes could just ignore it. The > >>>>>>>> forwarding > >>>>>>>> > >>>>>>>> > plane should work with co-existence of old and new nodes. Per > >>>>>>>> flex-algo adj- > >>>>>>>> > >>>>>>>> > sid is only local significant to one node. New nodes should > >>>>>>>> detect whether > >>>>>>>> > >>>>>>>> > legacy nodes exist in the network via such new extension > >>>>>>>> advertisement. > >>>>>>>> > >>>>>>>> > And new nodes should use only algo 0 adj-sid from legacy nodes > >>>>>>>> for any TI- > >>>>>>>> > >>>>>>>> > LFA. > >>>>>>>> > >>>>>>>> [LES:] Consider a network of 100 nodes. > >>>>>>>> > >>>>>>>> Let's say the "left-hand-side" of the network consist of legacy > >>>>>>>> nodes who do not understand your new advertisements. > >>>>>>>> > >>>>>>>> The "right-hand-side" of the network consists of upgraded nodes who > >>>>>>>> support the new advertisements. > >>>>>>>> > >>>>>>>> Consider nodes PE-LEFT and PE-RIGHT. > >>>>>>>> > >>>>>>>> PE-RIGHT advertises a prefix-SID of 1000 for 2.2.2.2/32, and an > >>>>>>>> offset of 1000 for flex-algo 128. > >>>>>>>> > >>>>>>>> PE-LEFT supports flex-algo 128 and wants to install a forwarding > >>>>>>>> entry for 2.2.2.2 for flex-algo 128. > >>>>>>>> > >>>>>>>> It looks in the LSPs originated by PE-RIGHT. It does not see any > >>>>>>>> assigned SID for 2.2.2.2/32 flex-algo 128. > >>>>>>>> > >>>>>>>> It cannot create a forwarding entry. And neither can any other node > >>>>>>>> in the left hand side of the network. > >>>>>>>> > >>>>>>>> When PE-RIGHT stops advertising the explicit prefix SID for > >>>>>>>> 2.2.2.2/32 Algo 128, all legacy nodes are unable to create > >>>>>>>> forwarding entries for the prefix/algo tuple. > >>>>>>>> > >>>>>>>> This isn’t backwards compatible. > >>>>>>>> > >>>>>>>> In general, you cannot advertise information legacy nodes require in > >>>>>>>> a new container that legacy nodes do not understand and claim that > >>>>>>>> you are backwards compatible. > >>>>>>>> > >>>>>>>> [lc2] Please refers to the examples for clarification. > >>>>>>>> > >>>>>>>> 1. > >>>>>>>> > >>>>>>>> For existing Flex-Algo deployment, it would be compatible. There > >>>>>>>> is no change in the container format on how prefix-sid > >>>>>>>> 2.2.2.2/32 in FA128 is advertised. > >>>>>>>> > >>>>>>>> 1. > >>>>>>>> > >>>>>>>> For new VFA, it would not be compatible. But….it does not mean > >>>>>>>> that we could not have VFA running in the same network. > >>>>>>>> > >>>>>>>> There could be procedures to enhance such. With your example, one > >>>>>>>> workaround could be: > >>>>>>>> > >>>>>>>> For VFA 600, PE-RIGHT detects that PE-LEFT does not participate in > >>>>>>>> VFA600 (due to no offset advertisement seen), > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Either, it spawns new CSPF for VFA600 instead of sharing FA129’s > >>>>>>>> result. Bypass PE-LEFT as a result. > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Or, it uses legacy node FA129 prefix-sid and adj-sid as > >>>>>>>> replacement (note: this method needs more comment) > >>>>>>>> > >>>>>>>> In either ways, VFA600 could work without issue even with legacy > >>>>>>>> nodes co-existence. > >>>>>>>> > >>>>>>>> After PE-LEFT upgraded, VFA600 would be using FA129 CSPF result > >>>>>>>> instead, and save CPU resources in each node. > >>>>>>>> > >>>>>>>> Another question: do we need FAD for VFA600? Currently, no. Not > >>>>>>>> mandatory. > >>>>>>>> > >>>>>>>> But it could be considered if “good to have” parameters are passed > >>>>>>>> along with FAD. > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > I do not see a major problem. Please give me an example to > >>>>>>>> illustrate your > >>>>>>>> > >>>>>>>> > concern if possible. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Of course, we need to do double check on the claim and > >>>>>>>> possibly lab > >>>>>>>> > >>>>>>>> > verification to see if the backward compatibility could be > >>>>>>>> achieved. It could > >>>>>>>> > >>>>>>>> > be vendor specific. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > What does deserve discussion is a "hitless migration strategy". > >>>>>>>> When full > >>>>>>>> > >>>>>>>> > support is available, if you were to switch to the new scheme, > >>>>>>>> you would > >>>>>>>> > >>>>>>>> > want to do so without changing any existing SIDs as > >>>>>>>> this would avoid > >>>>>>>> > >>>>>>>> > forwarding disruption. Which means operators would have to modify > >>>>>>>> their > >>>>>>>> > >>>>>>>> > SID assignment scheme in advance of deploying the new scheme. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] For VFA, there would be issue for legacy nodes. I agree. In > >>>>>>>> this case, > >>>>>>>> > >>>>>>>> > solution could be > >>>>>>>> > >>>>>>>> > - either have a fallback plan for newer nodes if > >>>>>>>> detection of legacy nodes > >>>>>>>> > >>>>>>>> > exist in the network. E.g. spawn new CSPF > >>>>>>>> > >>>>>>>> > - or, totally not to deploy VFA unless all nodes are > >>>>>>>> upgraded. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Section 5 is not updated with VFA inclusion. > >>>>>>>> > >>>>>>>> [LES:] My comments have nothing to do with VFA. > >>>>>>>> > >>>>>>>> Please reconsider them after you have understood the backwards > >>>>>>>> compatibility issues. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 3)Virtual Flex Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > You have introduced a new concept with very little explanation of > >>>>>>>> what it is > >>>>>>>> > >>>>>>>> > nor how it can be supported. > >>>>>>>> > >>>>>>>> > For example, how would we determine which nodes support a given VFA? > >>>>>>>> > >>>>>>>> > Since the algorithm value must be greater than 255, it cannot be > >>>>>>>> advertised in > >>>>>>>> > >>>>>>>> > the existing SR Algorithm sub-TLV. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If you are serious about this idea, please provide a > >>>>>>>> more complete > >>>>>>>> > >>>>>>>> > discussion. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] We could illustrate application examples in next > >>>>>>>> presentation. For > >>>>>>>> > >>>>>>>> > ethernet, we have port, and then we have VLAN and stacked vlan. > >>>>>>>> History > >>>>>>>> > >>>>>>>> > has some hints on this. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] You are writing a normative specification. Hoping that all > >>>>>>>> readers/implementors have the same "intuition" isn’t sufficient. > >>>>>>>> > >>>>>>>> Les > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 4)Section 4.3 > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > "R" and "N" flags are now defined in prefix attributes sub-TLV > >>>>>>>> (RFC7794) > >>>>>>>> > >>>>>>>> > They were originally defined in the SR sub-TLV because RFC 7794 > >>>>>>>> did not exist > >>>>>>>> > >>>>>>>> > at the time. > >>>>>>>> > >>>>>>>> > The only reason they continue to exist in RFC 8667 is > >>>>>>>> for backwards > >>>>>>>> > >>>>>>>> > compatibility with early implementation of SR-MPLS based on early > >>>>>>>> drafts of > >>>>>>>> > >>>>>>>> > what became RFC 8667. > >>>>>>>> > >>>>>>>> > Please do not introduce them in new sub-TLVs - there is no need. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] noted with thanks [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 5)ADJ-SIDs are NOT allocated from the SRGB as they are local in > >>>>>>>> scope. > >>>>>>>> > >>>>>>>> > They MAY be allocated from the SRLB - or outside either GB range. > >>>>>>>> > >>>>>>>> > Please correct the document in this regard. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] noted [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Les > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > -----Original Message----- > >>>>>>>> > >>>>>>>> > > From: Lsr <lsr-bounces@ietf.org <mailto:lsr-bounces@ietf.org>> > >>>>>>>> On Behalf Of Acee Lindem > >>>>>>>> > >>>>>>>> > > Sent: Friday, April 7, 2023 11:43 AM > >>>>>>>> > >>>>>>>> > > To: Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>> > >>>>>>>> > >>>>>>>> > > Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for > >>>>>>>> Advertising > >>>>>>>> > >>>>>>>> > > Offset for Flex-Algorithm > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Hi Louis, > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > In the interest of initiating discussion, I would like to > >>>>>>>> propose the > >>>>>>>> > >>>>>>>> > > term "Flex Algorithm Traffic Class (FATC)" for the > >>>>>>>> sub-division of > >>>>>>>> > >>>>>>>> > > flex-algorithm traffic referred to in the draft as “Virtual > >>>>>>>> Flex Algorithm”. > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Also, in your terminology, you refer referred to TLVs and > >>>>>>>> fields with > >>>>>>>> > >>>>>>>> > > simply “Algorithm” when RFC 9350 uses “Flex Algorithm”. > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Thanks, > >>>>>>>> > >>>>>>>> > > Acee > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > _______________________________________________ > >>>>>>>> > >>>>>>>> > > Lsr mailing list > >>>>>>>> > >>>>>>>> > > Lsr@ietf.org <mailto:Lsr@ietf.org> > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/ > >>>>>>>> l > >>>>>>>> s > >>>>>>>> r_ > >>>>>>>> <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/ > >>>>>>>> l > >>>>>>>> s > >>>>>>>> r_> > >>>>>>>> > >>>>>>>> > > _;!!NEt6yMaO-gk!B9ufrV6k- > >>>>>>>> > >>>>>>>> > c7mtP9JUiXbrF3NCkZ15_UMLBjV_fnJovfz18M5VkkI2F > >>>>>>>> > >>>>>>>> > > EoixpkxsfMnbqwbR0bpHgoS9E$ > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Juniper Business Use Only > >>>>>>>> > >>>>>>>> Juniper Business Use Only > >>>>>>>> > >>>>>>>> > >>>>>>>> Juniper Business Use Only > >>>>>>>> > >>>>>>> > >>>>>>> _______________________________________________ > >>>>>>> Lsr mailing list > >>>>>>> Lsr@ietf.org > >>>>>>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/l > >>>>>>> s > >>>>>>> r > >>>>>>> __;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtcjGl2sqxcDIFHFZRnk4pocYHUxv9_p > >>>>>>> A > >>>>>>> b > >>>>>>> 8cfeVdGYX_3gOEDi1kljo7ufGA$ > >>>>>>> ------------------------------------------------------------------- > >>>>>>> - > >>>>>>> - > >>>>>>> ---------------------------------------------------------------- > >>>>>>> 本邮件及其附件含有新华三集团的保密信息,仅限于发送给上面地址中列出 > >>>>>>> 的个人或群组。禁止任何其他人以任何形式使用(包括但不限于全部或 > 部分地泄露、复制、 > >>>>>>> 或散发)本邮件中的信息。如果您错收了本邮件,请您立即电话或邮件 > 通知发件人并删除本 > >>>>>>> 邮件! > >>>>>>> This e-mail and its attachments contain confidential information > >>>>>>> from New H3C, which is intended only for the person or entity whose > >>>>>>> address is listed above. Any use of the information contained > >>>>>>> herein in any way (including, but not limited to, total or partial > >>>>>>> disclosure, reproduction, or dissemination) by persons other than > >>>>>>> the intended > >>>>>>> recipient(s) is prohibited. If you receive this e-mail in error, > >>>>>>> please notify the sender by phone or email immediately and delete it! > >>>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> > >>>>> Juniper Business Use Only > >>>>> > >>>> > >>>> > >>>> Juniper Business Use Only > >>>> > >>> > >>> > >>> Juniper Business Use Only > >>> > >> > >> > >> _______________________________________________ > >> Lsr mailing list > >> Lsr@ietf.org > >> https://www.ietf.org/mailman/listinfo/lsr > >> > >> > >> > >> > >> _______________________________________________ > >> Lsr mailing list > >> Lsr@ietf.org > >> https://www.ietf.org/mailman/listinfo/lsr > >> > > > > > > > > > > > > > Subject:Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising OffsetforFlex-Algorithm > > Weiqiang, > > On 14/04/2023 13:36, Weiqiang Cheng wrote: > > Hi Peter, > > Your information about the deployment is good. > > It is clear there are two different application scenarios: > > 1. For the operators who only need few algos, the current solution is good enough for them, they just need keep it and don't need to worry about the updates. > > 2. For the operators who need more algos, they have no legacy deployment. The new solutions we talked about are good for them. > > > > Now, we need the new solution for the second scenario. > > here we disagree. The existing encoding works just fine for both. > The fact that it may be optimized, does not mean it is a good idea to do so. > > thanks, > Peter > > > > > B.R. > > Weiqiang Cheng > > > > -----邮件原件----- > > 发件人: Peter Psenak [mailto:ppsenak@cisco.com] > > 发送时间: 2023年4月14日 19:03 > > 收件 > 人: Weiqiang Cheng; 'Peter Psenak'; 'Louis Chan'; 'linchangwang'; 'Les Ginsberg (ginsbe'; 'Acee Lindem' > > 抄送: 'lsr'; 'Krzysztof Szarkowicz' > > 主题: Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > > > > Weiqiang, > > > > On 14/04/2023 12:28, Weiqiang Cheng wrote: > >> Hi Peter, > >> As far as I know, Flex Algo is not really deployed by operators by now, mainly because of the scalability concerns. > > > > I know bunch that deployed it and are happy with it. They needed few > > algos, which is what I consider the right usage of it. > > > > thanks, > > Peter > > > >> In fact, the Luois team and our team did not know each other before. However, we proposed solutions for MPLS-SR and SRv6 respectively almost at the same time. So you can see it is a common problem for those operators who want to deploy FA at scale. > >> > >> As discussion in last few days, my observation is that we've agreed the problem is there. > >> I think it's a good time to address it now.I suggest that We can discuss more on the solutions further, instead of discussing the requirements. > >> > >> B.R. > >> Weiqiang Cheng > >> > >> > >> -----邮件原件----- > >> 发件人: Lsr [mailto:lsr-bounces@ietf.org] 代表 Peter Psenak > >> 发送时间: 2023年4月14日 16:51 > >> 收件人: Louis Chan; linchangwang; 程伟 > 强; Les Ginsberg (ginsbe; Acee Lindem > >> 抄送: lsr; Krzysztof Szarkowicz > >> 主题: Re: [Lsr] IETF- > 116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > >> > >> Louis, > >> > >> On 14/04/2023 10:25, Louis Chan wrote: > >>> Hi Peter, > >>> > >>> I do not think we should divert the focus. It is about efficiency in packing information. > >> > >> trying to change the way the protocol encodes existing data is something > >> that we should not do, unless there is a blocking issue that does not > >> allow protocol to work anymore with existing encoding. You have not > >> provided evidence of that. All the claims so far have been around the > >> lines of implementation efficiency and can be addressed by existing > >> protocol mechanism. > >> > >>> > >>> If some important info is required to pass as "necessary evil", then it should. > >>> > >>> Actually, I am looking forward to applying similar method for other metric or ASLA, proposed by someone, and not necessary by me. And I have seen some drafts are addressing this kind of issues. > e.g. For FA200 and FA201, most link metrics are sharing the same > >> values, but only 5% difference in order to achieve some desired > >> behavior. In this case, we should find a way to pack it efficiently. > >> > >> maybe you need a new version of the protocol to do what you propose. > >> > >> thanks, > >> Peter > >> > >>> > >>> Rgds > >>> Louis > >>> > >>> -----Original Message----- > >>> From: Peter Psenak <ppsenak@cisco.com> > >>> Sent: Friday, April 14, 2023 3:32 PM > >>> To: Louis Chan <louisc@juniper.net>; linchangwang <linchangwang.04414@h3c.com>; 程伟强 <chengweiqiang@chinamobile.com>; Les Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem <acee.ietf@gmail.com> > >>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz <kszarkowicz@juniper.net> > >>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising Offset forFlex-Algorithm > >>> > >>> [External Email. Be cautious of content] > >>> > >>> > >>> Louis, > >>> > >>> On 14/04/2023 07:38, Louis Chan wrote: > >>>> Hi Peter, > >>>> > >>>> For Adj-sid and additional TE requirement, I am not sure what you refer to. > >>>> TE requirement or metric requirement? If it is metric related, we have ASLA draft to address some TE related problem. > >>>> (To me, to reduce ASLA advertisement is required too.) > >>>> > >>>> What TE problem are you referring to? Could you give an example to illustrate you concern? > >>> > >>> there are many TE attributes flooded for TE purposes, e.g., reserved/unreserved bandwidth (per pool), SRLGs, affinities, ... > >>> > >>> You are picking Ajd-SID, but that is not the only thing that is advertised per link. You may have many SRLGs, many affinities, etc. > >>> > >>> > >>> Peter > >>> > >>>> > >>>> Rgds > >>>> Louis > >>>> > >>>> -----Original Message----- > >>>> From: Peter Psenak <ppsenak@cisco.com> > >>>> Sent: Thursday, April 13, 2023 5:09 PM > >>>> To: Louis Chan <louisc@juniper.net>; linchangwang > >>>> <linchangwang.04414@h3c.com>; 程伟 > 强 <chengweiqiang@chinamobile.com>; Les > >>>> Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem > >>>> <acee.ietf@gmail.com> > >>>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz <kszarkowicz@juniper.net> > >>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>> Offset forFlex-Algorithm > >>>> > >>>> [External Email. Be cautious of content] > >>>> > >>>> > >>>> Loius, > >>>> > >>>> there are many reasons why we need to advertise additional data for adjacency - TE being a major one. You are trying to optimize the Adj-SID only, which is not the major contributor anyway. The problem is not specific to Adj-SID. > >>>> > >>>> In terms of convergence, if you are worried about the flooding speed, there is a draft in progress: > >>>> > >>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-iet > >>>> f-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!B1_2-Ht7ugsG_Wz7Ii0QGroMZyo9 > >>>> HTCDcsgefE_pSNK-2bIfNoekducPbd5X3kQ5eMiRk98Jb_PYYg$ > >>>> > >>>> thanks, > >>>> Peter > >>>> > >>>> > >>>> > >>>> On 13/04/2023 10:52, Louis Chan wrote: > >>>>> Hi Peter/all, > >>>>> > >>>>> Here I do a simple analysis on this scaling issue. > >>>>> > >>>>> 1. Assume a network with these parameters > >>>>> - 20 x Flex-algo > >>>>> - 2 x core nodes with 1,000 links > >>>>> - network diameter with 5 hops > >>>>> > >>>>> 2. Just check out the additional advertisement size from core nodes following ChangWang example. > >>>>> > >>>>> For 1 core node, > >>>>> n x 20 x 1000 > >>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes per core node > >>>>> > >>>>> With 2 core nodes, it is 400KB in total > >>>>> > >>>>> LSP num: 400KB/1500 = 267 lsps, at least > >>>>> > >>>>> 3. About the delivery/flooding rate, from > >>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft-ie > >>>>> t > >>>>> f-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!B1_2-Ht7ugsG_Wz7Ii0QGroMZyo > >>>>> 9 HTCDcsgefE_pSNK-2bIfNoekducPbd5X3kQ5eMiRk98Jb_PYYg$ > >>>>>>>> > >>>>> As IS-IS is deployed in greater scale both in the number of nodes in > >>>>> an area and in the number of neighbors per node, the impact of the > >>>>> historic flooding rates becomes more significant. Consider the > >>>>> bringup or failure of a node with 1000 neighbors. This will result <--- 1000 adj links > >>>>> in a minimum of 1000 LSP updates. At typical LSP flooding rates used <--- imply 1000 LSP updates > >>>>> today (33 LSPs/second), it would take 30+ seconds simply to send the <--- 33lsp/s > >>>>> updated LSPs to a given neighbor. Depending on the diameter of the > >>>>> network, achieving a consistent LSDB on all nodes in the network > >>>>> could easily take a minute or more. <--- at least double > >>>>> <<< > >>>>> > >>>>> 267/33 = 8.1 sec > >>>>> > >>>>> > >>>>> With a network diameter of 5, the additional time for delivering the consistent LSDB to all remote nodes = > >>>>> m x 8.1 sec, where 1 < m < 5 due to inefficiency or implementation issue > >>>>> > >>>>> It is likely 16+ sec, according to the above description in that draft. > >>>>> > >>>>> If using offset solution, it is around 0.008sec x 2 = 0.016sec in additional. This number is small. > >>>>> > >>>>> Additional of 16+ sec is significant in global convergence time. > >>>>> > >>>>> 4. This model/example does not include nodes from second layer, which also has 2 x 1,000 adj-sid in the reverse direction. The total number would be estimated bigger than 30+ sec. > >>>>> > >>>>> Should this be improved? > >>>>> > >>>>> 5. Flooding could be in all directions. Larger size of advertisement could delay some important update in busy period. i.e. smaller size in advertisement is better. > >>>>> And I assume this draft with offset would also reduce the refresh requirement. > >>>>> > >>>>> Rgds > >>>>> Louis > >>>>> > >>>>> -----Original Message----- > >>>>> From: Peter Psenak <ppsenak@cisco.com> > >>>>> Sent: Wednesday, April 12, 2023 11:26 PM > >>>>> To: linchangwang <linchangwang.04414@h3c.com>; 程伟强 > >>>>> <chengweiqiang@chinamobile.com>; Louis Chan <louisc@juniper.net>; Les > >>>>> Ginsberg (ginsbe <ginsberg@cisco.com>; Acee Lindem > >>>>> <acee.ietf@gmail.com> > >>>>> Cc: lsr <lsr@ietf.org>; Krzysztof Szarkowicz > >>>>> <kszarkowicz@juniper.net> > >>>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>> Offset forFlex-Algorithm > >>>>> > >>>>> [External Email. Be cautious of content] > >>>>> > >>>>> > >>>>> Hi Changwang, > >>>>> > >>>>> please see inline ##PP3: > >>>>> > >>>>> On 12/04/2023 16:46, linchangwang wrote: > >>>>>> Hi Peter, > >>>>>> > >>>>>> > >>>>>> Please see inline [changwang lin]. > >>>>>> > >>>>>>> Changwang, > >>>>>> > >>>>>>> please see inline (##PP2): > >>>>>> > >>>>>> > >>>>>> On 12/04/2023 15:13, linchangwang wrote: > >>>>>>> Hi Peter > >>>>>>> > >>>>>>> Please see inline [changwang lin]. > >>>>>>> > >>>>>>>> We've met the same problem when applying Flex Algo in SRv6 network. > >>>>>>> > >>>>>>> what problem exactly, can you please describe it? > >>>>>>> > >>>>>>> [changwang lin] > >>>>>>> Advertisement size of per Flex-Algo Adj-SID in the network Related > >>>>>>> to F(# of node, # of FA, # of links) For a node with 1,000 links > >>>>>>> and > >>>>>>> 20 Flex-Algo > >>>>>>> n x 20 x 1000 > >>>>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes > >>>>>>> SRv6: If n = 24 bytes, it is 400K+ bytes > >>>>>>> If 500 nodes: > >>>>>>> MPLS-SR:it is 200K*500 = 100000k bytes > >>>>>>> SRv6: it is 400K+ * 500 = 200000k bytes > >>>>>>> If interface mtu=1500, lsp length = 1497 > >>>>>>> LSPs num: > >>>>>>> MPLS-SR:10000k bytes/1497 = 66800 lsps > >>>>>>> SRv6: 20000k bytes/1497 = 160320 lsps > >>>>>>> > >>>>>>> The number of LSPs is too large, and IS-IS needs to periodically > >>>>>>> refresh LSPs, resulting in a decrease in ISIS performance and unstable network operation. > >>>>>> > >>>>>> ##PP2 > >>>>>> above is hardly a realistic estimation. > >>>>>> > >>>>>> In a network with 1k nodes, not every node will have 1k links. > >>>>>> > >>>>>> Advertising large number of LSPs is not caused by Adj-SIDs. > >>>>>> With TE enabled the amount of data flooded per link is larger than > >>>>>> advertisement of the 20 Adj-SID. The problem you are highlighting is > >>>>>> not specific to Adj-SIDs, it's generic. > >>>>>> > >>>>>> LSP refresh time can be set to 18 hours and any reasonable > >>>>>> implementation does not refresh all LSPs at the same time. > >>>>>> > >>>>>> [changwang lin] > >>>>>> This problem exists in actual operator networking, it can be calculated based on an actual network as follows: > >>>>>> One network with 200 nodes > >>>>>> One node with 20 interfaces > >>>>>> One interface with 32 flex algos Each interface is assigned two > >>>>>> types of end. x, one PSP and one non PSP, with each end. x occupying > >>>>>> 30 bytes An nbr tlv with basic bandwidth, EAG, and interface address > >>>>>> is approximately 140 bytes Number of LSPs in the entire network: 140 > >>>>>> * 20 * 32 * 200/1497=12000 LSPs > >>>>>> > >>>>>> The performance of IGP has always been affected by the size of the > >>>>>> entire network's LSDB, and even if the periodic flooding time is reduced, there will still be convergence issues. > >>>>> > >>>>> ##PP3 > >>>>> I don't see any relationship between the convergence and the fact that you have to advertise 20 ADJ-SIDs per link. If there is one, it's an implementation problem. > >>>>> > >>>>> > >>>>>> > >>>>>>> > >>>>>>> So we need to optimize on the control surface to save LSP space. > >>>>>> > >>>>>> ##PP2 > >>>>>> with all the respect, I don't agree. The problem as you described it > >>>>>> does not exist. > >>>>>> [changwang lin] > >>>>>> In the actual deployment of MPLS-SR and SRv6 networks, as the number > >>>>>> of flex algos and interfaces increases, the space occupied by adj-sids becomes larger and larger. > >>>>>> This is the actual problem when deploying flex algos. > >>>>> > >>>>> ##PP3 > >>>>> I don't see any protocol problem. > >>>>> > >>>>> > >>>>>> > >>>>>>> Through the optimization notification mechanism mentioned in these > >>>>>>> two documents, we have greatly saved LSP space for IS-IS and improved the performance of IS-IS flex algo in large-scale networking. > >>>>>>> At the same time, through the VFA mechanism, in other non flex algo application scenarios, > >>>>>>> such as network slicing scenarios, the LSP space of IS-IS can > >>>>>>> also be saved > >>>>>> > >>>>>> ##PP2 > >>>>>> it seems to me you are trying to fix the implementation problem with > >>>>>> the protocol changes, which is never a good idea. > >>>>>> > >>>>>> [changwang lin] > >>>>>> In actual deployment, a flex algo corresponds to the SLA > >>>>>> requirements of a service, such as different bandwidth guarantees, > >>>>>> 128 flex algos can correspond to 128 service requirements. > >>>>>> When the flex algo specification increases, the corresponding number of LSPs rapidly increases, making it impossible to deploy large flex algo applications. > >>>>>> And the mechanism of this draft can greatly improve the space utilization of LSP.. > >>>>> > >>>>> ##PP3 > >>>>> I appreciate your effort, but I don't believe the proposed compression is needed, nor that it addresses the problem you have. > >>>>> > >>>>> The amount of data being flooded per adjacency may potentially be large and Adj-SIDs only represent a fraction of it - even with 32 Adj-SIDs per link you are not hitting any protocol limitation. > >>>>> > >>>>> thanks, > >>>>> Peter > >>>>> > >>>>> > >>>>>> > >>>>>> thanks, > >>>>>> Changwang lin > >>>>>> > >>>>>> > >>>>>> > >>>>>>> thanks, > >>>>>>> Peter > >>>>>> > >>>>>>> > >>>>>>> > >>>>>>> thanks, > >>>>>>> Changwang lin > >>>>>>> > >>>>>>> > >>>>>>> -----Original Message----- > >>>>>>> From: Lsr [mailto:lsr-bounces@ietf.org] On Behalf Of Peter Psenak > >>>>>>> Sent: Wednesday, April 12, 2023 7:10 PM > >>>>>>> To: 程伟强; Louis Chan; Les Ginsberg (ginsbe; Acee Lindem > >>>>>>> Cc: lsr; Krzysztof Szarkowicz > >>>>>>> Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>> Offset forFlex-Algorithm > >>>>>>> > >>>>>>> Weiqiang, > >>>>>>> > >>>>>>> please see inline (##PP): > >>>>>>> > >>>>>>> On 12/04/2023 12:05, 程伟强 wrote: > >>>>>>>> Hi Louis and Les, > >>>>>>>> > >>>>>>>> > >>>>>>>> My two cents from operator perspective. > >>>>>>>> > >>>>>>>> > >>>>>>>> We've met the same problem when applying Flex Algo in SRv6 network. > >>>>>>> > >>>>>>> what problem exactly, can you please describe it? > >>>>>>> > >>>>>>> [changwang lin] > >>>>>>> Advertisement size of per Flex-Algo Adj-SID in the network Related > >>>>>>> to F(# of node, # of FA, # of links) For a node with 1,000 links > >>>>>>> and > >>>>>>> 20 Flex-Algo > >>>>>>> n x 20 x 1000 > >>>>>>> MPLS-SR:If n = 10 bytes, it is 200K bytes > >>>>>>> SRv6: If n = 24 bytes, it is 400K+ bytes > >>>>>>> If 500 nodes: > >>>>>>> MPLS-SR:it is 200K*500 = 100000k bytes > >>>>>>> SRv6: it is 400K+ * 500 = 200000k bytes > >>>>>>> If interface mtu=1500, lsp length = 1497 > >>>>>>> LSP num: > >>>>>>> MPLS-SR:10000k bytes/1497 = 66800 lsps > >>>>>>> SRv6: 20000k bytes/1497 = 160320 lsps > >>>>>>> > >>>>>>> The number of LSPs is too large, and IS-IS needs to periodically > >>>>>>> refresh LSPs, resulting in a decrease in ISIS performance and unstable network operation. > >>>>>>> > >>>>>>> So we need to optimize on the control surface to save LSP space. > >>>>>>> Through the optimization notification mechanism mentioned in these > >>>>>>> two documents, we have greatly saved LSP space for IS-IS and improved the performance of IS-IS flex algo in large-scale networking. > >>>>>>> At the same time, through the VFA mechanism, in other non flex algo application scenarios, > >>>>>>> such as network slicing scenarios, the LSP space of IS-IS can > >>>>>>> also be saved > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> As the number of slices and the scale of the network increases, > >>>>>>>> the convergence issue which is caused by SIDs advertising and > >>>>>>>> flooding becomes more and more serious. > >>>>>>>> > >>>>>>>> > >>>>>>>> Due to the problem, it is impossible to apply Flex-Algo in the > >>>>>>>> large network, such as the network with more than 1000 routers. > >>>>>>> > >>>>>>> flex-algo has been successfully deployed in a networks that have > >>>>>>> more that 1k nodes. > >>>>>>> > >>>>>>> Maybe you want deploy the flex-algo for something that it was not > >>>>>>> designed for. > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> I believe Louis'draft provides a good idea to resolve this problem. > >>>>>>>> Similar solution for SRv6 SIDs is described in another draft. > >>>>>>> > >>>>>>> Again, what problem exactly? > >>>>>>> > >>>>>>> From what I see the drafts tries to pack algo SIDs to save > >>>>>>> space in LSP. I don't see how it helps to to deploy flex-algo in a > >>>>>>> large scale network. > >>>>>>> > >>>>>>> thanks, > >>>>>>> Peter > >>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> About the SIDs assignment, I think it is better to have a > >>>>>>>> scheduled assignment than a random assignment as Les mentioned. > >>>>>>>> > >>>>>>>> > >>>>>>>> [1] > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft > >>>>>>>> - > >>>>>>>> c > >>>>>>>> heng-lsr-isis-srv6-sid-block/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrt > >>>>>>>> c j Gl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kmvLCcctw$ > >>>>>>>> <https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draf > >>>>>>>> t > >>>>>>>> - > >>>>>>>> cheng-lsr-isis-srv6-sid-block/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMr > >>>>>>>> t c jGl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kmvLCcctw$ > > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> Thanks, > >>>>>>>> > >>>>>>>> Weiqiang Cheng > >>>>>>>> > >>>>>>>> > >>>>>>>> > >>>>>>>> ----邮件原文---- > >>>>>>>> *发件 > 人:*Louis Chan <louisc=40juniper.net@dmarc.ietf.org> > >>>>>>>> *收件 > >>>>>>>> 人:*"Les Ginsberg (ginsberg)" <ginsberg@cisco.com>,Acee Lindem <acee.ietf@gmail.com> > >>>>>>>> *抄 送: > >>>>>>>> *lsr <lsr@ietf.org>,Krzysztof Szarkowicz <kszarkowicz@juniper.net>,Weiqiang Cheng <chengweiqiang@chinamobile.com> > >>>>>>>> *发送时间:*2023-04-12 10:45:56 > >>>>>>>> *主题:*Re: [Lsr] IETF- > >>>>>>>> 116 LSR - IGP extensions for Advertising Offset > >>>>>>>> forFlex-Algorithm > >>>>>>>> > >>>>>>>> Hi Les, > >>>>>>>> > >>>>>>>> Thanks for the prompt reply. Please see inline for clarification [lc2]. > >>>>>>>> > >>>>>>>> /Louis > >>>>>>>> > >>>>>>>> *From:* Les Ginsberg (ginsberg) <ginsberg@cisco.com> > >>>>>>>> *Sent:* Tuesday, April 11, 2023 11:03 PM > >>>>>>>> *To:* Louis Chan <louisc@juniper.net>; Acee Lindem <acee.ietf@gmail.com> > >>>>>>>> *Cc:* lsr <lsr@ietf.org>; Krzysztof Szarkowicz > >>>>>>>> <kszarkowicz@juniper.net>; Weiqiang Cheng > >>>>>>>> <chengweiqiang@chinamobile.com> > >>>>>>>> *Subject:* RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for Flex-Algorithm > >>>>>>>> > >>>>>>>> *[External Email. Be cautious of content]* > >>>>>>>> > >>>>>>>> Louis - > >>>>>>>> > >>>>>>>> Please see inline. > >>>>>>>> > >>>>>>>> > -----Original Message----- > >>>>>>>> > >>>>>>>> > From: Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > Sent: Monday, April 10, 2023 11:01 PM > >>>>>>>> > >>>>>>>> > To: Les Ginsberg (ginsberg) <ginsberg@cisco.com > >>>>>>>> <mailto:ginsberg@cisco.com>>; Acee Lindem > >>>>>>>> > >>>>>>>> > <acee.ietf@gmail.com <mailto:acee.ietf@gmail.com>> > >>>>>>>> > >>>>>>>> > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>>; Krzysztof > >>>>>>>> Szarkowicz <kszarkowicz@juniper.net > >>>>>>>> <mailto:kszarkowicz@juniper.net>>; > >>>>>>>> > >>>>>>>> > Weiqiang Cheng <chengweiqiang@chinamobile.com > >>>>>>>> <mailto:chengweiqiang@chinamobile.com>> > >>>>>>>> > >>>>>>>> > Subject: RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for > >>>>>>>> > >>>>>>>> > Flex-Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Hi Les, > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Thanks for your questions. Please see inline [lc] below. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > /Louis > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > -----Original Message----- > >>>>>>>> > >>>>>>>> > From: Les Ginsberg (ginsberg) <ginsberg@cisco.com > >>>>>>>> <mailto:ginsberg@cisco.com>> > >>>>>>>> > >>>>>>>> > Sent: Saturday, April 8, 2023 7:34 AM > >>>>>>>> > >>>>>>>> > To: Acee Lindem <acee.ietf@gmail.com > >>>>>>>> <mailto:acee.ietf@gmail.com>>; Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>> > >>>>>>>> > >>>>>>>> > Subject: RE: [Lsr] IETF-116 LSR - IGP extensions for Advertising > >>>>>>>> Offset for > >>>>>>>> > >>>>>>>> > Flex-Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [External Email. Be cautious of content] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > OK - since Acee opened the door - here are some > >>>>>>>> comments from me - > >>>>>>>> > >>>>>>>> > starting with the most important. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > (BTW - I still have limited enthusiasm for this draft.) > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 1)The proposal places some restrictions on how operators > >>>>>>>> provision their > >>>>>>>> > >>>>>>>> > network in terms of assigning SIDs and reserving space > >>>>>>>> for future > >>>>>>>> > >>>>>>>> > assignments. > >>>>>>>> > >>>>>>>> > If operators do not use compatible assignment schemes, then this > >>>>>>>> will never > >>>>>>>> > >>>>>>>> > get deployed. It is therefore not enough to come with a nice idea > >>>>>>>> - you must > >>>>>>>> > >>>>>>>> > have some enthusiasm from the operator community. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] If the operator only wants to deploy flex-algo, there is no > >>>>>>>> change in their > >>>>>>>> > >>>>>>>> > Node-sid numbering scheme. For the Adj-sid, these are local > >>>>>>>> labels with local > >>>>>>>> > >>>>>>>> > significant only, and there is no need for any special planning > >>>>>>>> for Adj-sid, > >>>>>>>> > >>>>>>>> > unless you are suggesting they want to make fixed assignment of > >>>>>>>> Adj-sid > >>>>>>>> > >>>>>>>> > label for each link. Even with fixed, the proposed draft has > >>>>>>>> benefit on that. I > >>>>>>>> > >>>>>>>> > will explain later. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] Let's discuss this in the context of prefix-sids - the same > >>>>>>>> applies to adj-sids. > >>>>>>>> > >>>>>>>> Today (i.e., in the absence of your proposal) an operator is free to > >>>>>>>> assign any label within the SRGB for a given prefix/algo pair so > >>>>>>>> long as it is not assigned to some other prefix/algo context. > >>>>>>>> > >>>>>>>> Your proposal places some new restrictions. Now, for a given > >>>>>>>> flex-algo, whenever an operator assigns a given label for a prefix > >>>>>>>> in Algo 0 (call it Label-A0), they must guarantee that > >>>>>>>> "Label-A0+offset" for an advertised flex-algo specific offset is > >>>>>>>> available to be assigned for the prefix/flex-algo pair - and this > >>>>>>>> must be true for all prefixes advertised in algo 0. > >>>>>>>> > >>>>>>>> This is certainly possible to do, but is not guaranteed to be the > >>>>>>>> case in current deployments. > >>>>>>>> > >>>>>>>> For example - and this is only an example...today an operator might > >>>>>>>> utilize a provisioning tool to assign prefix-sids for all supported > >>>>>>>> algorithms on all nodes in the network. > >>>>>>>> > >>>>>>>> To do this, the tool might maintain a database of assigned labels. > >>>>>>>> When provisioning a new node/prefix/algorithm, the logic in the tool > >>>>>>>> might simply take the next available label in the database. > >>>>>>>> > >>>>>>>> The result of this would not be consistent with the requirements of > >>>>>>>> your draft. > >>>>>>>> > >>>>>>>> Which is why I say in order to deploy the extension you propose, > >>>>>>>> such an operator would have to modify its provisioning tool. > >>>>>>>> > >>>>>>>> [lc2] There might be some misunderstanding of our proposal. Let me > >>>>>>>> give some examples. > >>>>>>>> > >>>>>>>> Case 1: Flex-Algo only > >>>>>>>> > >>>>>>>> Prefix offset advertisement: “no” > >>>>>>>> > >>>>>>>> Adj-sid offset advertisement: yes > >>>>>>>> > >>>>>>>> In slide 8’s example, FA129 is using label “402001”, and the > >>>>>>>> advertisement of this label is using existing methods. > >>>>>>>> > >>>>>>>> e.g. SRGB = 400000-460000 > >>>>>>>> > >>>>>>>> FA129: index 2001 (preferred value), or one can choose > >>>>>>>> 111, > >>>>>>>> 222 > >>>>>>>> > >>>>>>>> FA130 (new): index 3001 (preferred value), or 333, 4444 > >>>>>>>> > >>>>>>>> This does not change how the operator to assign label for prefix-sid > >>>>>>>> with their current method. Any index/label could be used for FA > >>>>>>>> prefix within SRGB. > >>>>>>>> > >>>>>>>> The only change is the Adj-sid label allocation, but this “mostly” > >>>>>>>> is only “local” to one node. There is no effect on global label > >>>>>>>> allocation. > >>>>>>>> > >>>>>>>> This draft will be compatible to what operators are doing today. > >>>>>>>> > >>>>>>>> Case 2: VFA only > >>>>>>>> > >>>>>>>> Prefix offset advertisement: yes > >>>>>>>> > >>>>>>>> Adj-sid offset advertisement: yes > >>>>>>>> > >>>>>>>> I agree, with VFA, there would be impact to global allocation to > >>>>>>>> node-sid/prefix-sid. But VFA is a totally new concept. No one has > >>>>>>>> deployed that yet. > >>>>>>>> > >>>>>>>> There is no impact to operators which stick to deploy only Flex-algo. > >>>>>>>> > >>>>>>>> Other case: Flex-Algo w/o Adj-sid offset > >>>>>>>> > >>>>>>>> Continue the example of Case#1 above > >>>>>>>> > >>>>>>>> Another FA131 is added, but no Adj-sid offset is > >>>>>>>> advertised > >>>>>>>> > >>>>>>>> The question would be > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Either allow this configuration, and FA131 will fallback using > >>>>>>>> Algo 0’s adj-sid > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Or, disallow this configuration > >>>>>>>> > >>>>>>>> I tend to “allow” such configuration with mix of FA129, FA130 (with > >>>>>>>> adj-sid offset) and FA131 (w/o adj-sid offset) > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> Could this be done? Sure. > >>>>>>>> > >>>>>>>> Do operators want to do this? I do not know. > >>>>>>>> > >>>>>>>> But since this would be necessary in order to use your proposed > >>>>>>>> extension, it is necessary to gauge operator enthusiasm for making > >>>>>>>> such changes in order to know whether there is any point in > >>>>>>>> proceeding with your proposal. > >>>>>>>> > >>>>>>>> > In slide 8 of the below presentation > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-__;!!NEt6yMaO-gk!EX4RtSVg7I0j > >>>>>>>> O > >>>>>>>> 4 > >>>>>>>> M9ZMrtcjGl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1knGgpMXww$ > >>>>>>>> <https://urldefense.com/v3/__https:/datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-igp-adv-offset-01__;!!NEt6yMa > >>>>>>>> O > >>>>>>>> - > >>>>>>>> gk!Bl7Swe9ql9VT0qGkD6FoZZzTWT2fmIx55eSncdmMgoCJetJ5-80micuqnqk79ye > >>>>>>>> w > >>>>>>>> G > >>>>>>>> B-BleOfrYpSjfI$> > >>>>>>>> > >>>>>>>> > igp-adv-offset-01 > >>>>>>>> > >>>>>>>> <https://urldefense.com/v3/__https:/datatracker.ietf.org/meeting/1 > >>>>>>>> 1 > >>>>>>>> 6 > >>>>>>>> /materials/slides-116-lsr-03-ietf116-igp-adv-offset-01__;!!NEt6yMa > >>>>>>>> O > >>>>>>>> - > >>>>>>>> gk!Bl7Swe9ql9VT0qGkD6FoZZzTWT2fmIx55eSncdmMgoCJetJ5-80micuqnqk79ye > >>>>>>>> w > >>>>>>>> G > >>>>>>>> B-BleOfrYpSjfI$> > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > FA129 is a prefix-sid (400201) allocated by operator, and it can > >>>>>>>> be any label. > >>>>>>>> > >>>>>>>> > There is no connection to how Adj-sid is derived. > >>>>>>>> > >>>>>>>> > Per Flex-Algo adj-sid assignment is not affecting > >>>>>>>> network wide label > >>>>>>>> > >>>>>>>> > assignment from operation perspective. Each node could have > >>>>>>>> different local > >>>>>>>> > >>>>>>>> > block for such adj-sid assignment. One might need to estimate > >>>>>>>> total possible > >>>>>>>> > >>>>>>>> > number of link in one chassis for such allocation, or it could be > >>>>>>>> estimated by > >>>>>>>> > >>>>>>>> > OS software itself. I also mentioned in the session, if there is > >>>>>>>> 100 x FA with > >>>>>>>> > >>>>>>>> > 1000 links (high end), it is only 100k labels. Is it difficult to > >>>>>>>> allocate such. > >>>>>>>> > >>>>>>>> [LES:] Your proposal does not reduce the number of labels which need > >>>>>>>> to be "allocated" and installed in forwarding, it only reduces the > >>>>>>>> number of bytes used to advertise this information in LSPs/LSAs. > >>>>>>>> > >>>>>>>> [lc2] You are correct. > >>>>>>>> > >>>>>>>> I think, at the same time, it helps reducing time for global > >>>>>>>> convergence since the advertisement size is smaller, especially in > >>>>>>>> network with long diameter with multi-hops. > >>>>>>>> > >>>>>>>> Also, in > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draft > >>>>>>>> - > >>>>>>>> ietf-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtc > >>>>>>>> j Gl2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kl_1f1RjQ$ > >>>>>>>> > >>>>>>>> <https://urldefense.com/v3/__https://datatracker.ietf.org/doc/draf > >>>>>>>> t > >>>>>>>> - > >>>>>>>> ietf-lsr-isis-fast-flooding/__;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtc > >>>>>>>> j G l2sqxcDIFHFZRnk4pocYHUxv9_pAb8cfeVdGYX_3gOEDi1kl_1f1RjQ$ > > >>>>>>>> (which you participated in) > >>>>>>>> > >>>>>>>> >>> > >>>>>>>> > >>>>>>>> As IS-IS is deployed in greater scale both in the > >>>>>>>> number of nodes in > >>>>>>>> > >>>>>>>> an area and in the number of neighbors per node, the > >>>>>>>> impact of the > >>>>>>>> > >>>>>>>> historic flooding rates becomes more significant. > >>>>>>>> Consider the > >>>>>>>> > >>>>>>>> bringup or failure of a node with 1000 neighbors. > >>>>>>>> This will result > >>>>>>>> > >>>>>>>> in a minimum of 1000 LSP updates. At typical LSP flooding rates > >>>>>>>> used > >>>>>>>> > >>>>>>>> today (33 LSPs/second), it would take 30+ seconds > >>>>>>>> simply to send the > >>>>>>>> > >>>>>>>> updated LSPs to a given neighbor. Depending on the > >>>>>>>> diameter of the > >>>>>>>> > >>>>>>>> network, achieving a consistent LSDB on all nodes in > >>>>>>>> the network > >>>>>>>> > >>>>>>>> could easily take a minute or more. > >>>>>>>> > >>>>>>>> <<< > >>>>>>>> > >>>>>>>> This proposed draft will certainly help. > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > So, this is why I do not understand your question in full. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If the operator plans to use VFA, that would be a different > >>>>>>>> discussion. VFA, > >>>>>>>> > >>>>>>>> > today, does not exist in deployment. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] My comments here have nothing to do with VFA. > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Have you discussed this idea with any operators? > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] I include Wei-qiang from China mobile in this thread. He has > >>>>>>>> shown his > >>>>>>>> > >>>>>>>> > need on this kind of solution. Maybe, he could give his > >>>>>>>> perspective here. [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If so, what has been their response? > >>>>>>>> > >>>>>>>> > If they are open to the idea, how might they migrate from their > >>>>>>>> existing > >>>>>>>> > >>>>>>>> > assignment schemes to an assignment scheme compatible > >>>>>>>> with the > >>>>>>>> > >>>>>>>> > proposal? > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > These are questions that need to be answered before considering > >>>>>>>> this idea. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] In slide 8, if you see these label numbers > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Prefix-sid: 400001, 402001, 406001, 407001 > >>>>>>>> > >>>>>>>> > Adj-sid: 32, 2032, 6032, 7032 > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > From operator perspective or troubleshooting perspective, value > >>>>>>>> xxx001 > >>>>>>>> > >>>>>>>> > represent the same node, and value x032 represent the > >>>>>>>> same link. This > >>>>>>>> > >>>>>>>> > makes things more organized and easier to understand. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If all are random labels, I do not see any benefit at all. > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> [LES:] I am not commenting on whether the label assignment scheme > >>>>>>>> you propose is better or worse than any other. > >>>>>>>> > >>>>>>>> I am only pointing out that you are imposing new restrictions on how > >>>>>>>> labels are allocated. > >>>>>>>> > >>>>>>>> As you are not in charge of how operators provision their networks > >>>>>>>> (nor am I), it is presumptuous of you to think that simply because > >>>>>>>> you think this is a better way to do things that operators will be > >>>>>>>> happy to modify their existing networks to conform to your proposed > >>>>>>>> restrictions. > >>>>>>>> > >>>>>>>> This isn’t academia - you need to vet this with the operator community. > >>>>>>>> > >>>>>>>> [lc2] Please refer to the examples at the top. The picture should be > >>>>>>>> clear by now. There is no restriction to what is deployed > >>>>>>>> today. [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 2)Section 5 Compatibilty > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > There is no "compatibility" with legacy nodes - because all nodes > >>>>>>>> in the > >>>>>>>> > >>>>>>>> > network have to have a consistent understanding of what SID is > >>>>>>>> assigned to a > >>>>>>>> > >>>>>>>> > given context (for prefixes and adjacencies) since they might > >>>>>>>> need to install > >>>>>>>> > >>>>>>>> > forwarding entries for that context. > >>>>>>>> > >>>>>>>> > I do not see any point in deploying this until all nodes support > >>>>>>>> it. If you did do > >>>>>>>> > >>>>>>>> > so, you would need to advertise old and new forms - > >>>>>>>> which does the > >>>>>>>> > >>>>>>>> > opposite of what you are trying to achieve. Instead of reducing > >>>>>>>> LSP space > >>>>>>>> > >>>>>>>> > used you would increase it. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] If the operator just plans to use only Flex-Algo, and no > >>>>>>>> VFA, it should be > >>>>>>>> > >>>>>>>> > compatible with legacy implementation. If legacy nodes do not > >>>>>>>> understand > >>>>>>>> > >>>>>>>> > adj-sid offset notation, these nodes could just ignore it. The > >>>>>>>> forwarding > >>>>>>>> > >>>>>>>> > plane should work with co-existence of old and new nodes. Per > >>>>>>>> flex-algo adj- > >>>>>>>> > >>>>>>>> > sid is only local significant to one node. New nodes should > >>>>>>>> detect whether > >>>>>>>> > >>>>>>>> > legacy nodes exist in the network via such new extension > >>>>>>>> advertisement. > >>>>>>>> > >>>>>>>> > And new nodes should use only algo 0 adj-sid from legacy nodes > >>>>>>>> for any TI- > >>>>>>>> > >>>>>>>> > LFA. > >>>>>>>> > >>>>>>>> [LES:] Consider a network of 100 nodes. > >>>>>>>> > >>>>>>>> Let's say the "left-hand-side" of the network consist of legacy > >>>>>>>> nodes who do not understand your new advertisements. > >>>>>>>> > >>>>>>>> The "right-hand-side" of the network consists of upgraded nodes who > >>>>>>>> support the new advertisements. > >>>>>>>> > >>>>>>>> Consider nodes PE-LEFT and PE-RIGHT. > >>>>>>>> > >>>>>>>> PE-RIGHT advertises a prefix-SID of 1000 for 2.2.2.2/32, and an > >>>>>>>> offset of 1000 for flex-algo 128. > >>>>>>>> > >>>>>>>> PE-LEFT supports flex-algo 128 and wants to install a forwarding > >>>>>>>> entry for 2.2.2.2 for flex-algo 128. > >>>>>>>> > >>>>>>>> It looks in the LSPs originated by PE-RIGHT. It does not see any > >>>>>>>> assigned SID for 2.2.2.2/32 flex-algo 128. > >>>>>>>> > >>>>>>>> It cannot create a forwarding entry. And neither can any other node > >>>>>>>> in the left hand side of the network. > >>>>>>>> > >>>>>>>> When PE-RIGHT stops advertising the explicit prefix SID for > >>>>>>>> 2.2.2.2/32 Algo 128, all legacy nodes are unable to create > >>>>>>>> forwarding entries for the prefix/algo tuple. > >>>>>>>> > >>>>>>>> This isn’t backwards compatible. > >>>>>>>> > >>>>>>>> In general, you cannot advertise information legacy nodes require in > >>>>>>>> a new container that legacy nodes do not understand and claim that > >>>>>>>> you are backwards compatible. > >>>>>>>> > >>>>>>>> [lc2] Please refers to the examples for clarification. > >>>>>>>> > >>>>>>>> 1. > >>>>>>>> > >>>>>>>> For existing Flex-Algo deployment, it would be compatible. There > >>>>>>>> is no change in the container format on how prefix-sid > >>>>>>>> 2.2.2.2/32 in FA128 is advertised. > >>>>>>>> > >>>>>>>> 1. > >>>>>>>> > >>>>>>>> For new VFA, it would not be compatible. But….it does not mean > >>>>>>>> that we could not have VFA running in the same network. > >>>>>>>> > >>>>>>>> There could be procedures to enhance such. With your example, one > >>>>>>>> workaround could be: > >>>>>>>> > >>>>>>>> For VFA 600, PE-RIGHT detects that PE-LEFT does not participate in > >>>>>>>> VFA600 (due to no offset advertisement seen), > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Either, it spawns new CSPF for VFA600 instead of sharing FA129’s > >>>>>>>> result. Bypass PE-LEFT as a result. > >>>>>>>> > >>>>>>>> * > >>>>>>>> > >>>>>>>> Or, it uses legacy node FA129 prefix-sid and adj-sid as > >>>>>>>> replacement (note: this method needs more comment) > >>>>>>>> > >>>>>>>> In either ways, VFA600 could work without issue even with legacy > >>>>>>>> nodes co-existence. > >>>>>>>> > >>>>>>>> After PE-LEFT upgraded, VFA600 would be using FA129 CSPF result > >>>>>>>> instead, and save CPU resources in each node. > >>>>>>>> > >>>>>>>> Another question: do we need FAD for VFA600? Currently, no. Not > >>>>>>>> mandatory. > >>>>>>>> > >>>>>>>> But it could be considered if “good to have” parameters are passed > >>>>>>>> along with FAD. > >>>>>>>> > >>>>>>>> [/lc2] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > I do not see a major problem. Please give me an example to > >>>>>>>> illustrate your > >>>>>>>> > >>>>>>>> > concern if possible. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Of course, we need to do double check on the claim and > >>>>>>>> possibly lab > >>>>>>>> > >>>>>>>> > verification to see if the backward compatibility could be > >>>>>>>> achieved. It could > >>>>>>>> > >>>>>>>> > be vendor specific. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > What does deserve discussion is a "hitless migration strategy". > >>>>>>>> When full > >>>>>>>> > >>>>>>>> > support is available, if you were to switch to the new scheme, > >>>>>>>> you would > >>>>>>>> > >>>>>>>> > want to do so without changing any existing SIDs as > >>>>>>>> this would avoid > >>>>>>>> > >>>>>>>> > forwarding disruption. Which means operators would have to modify > >>>>>>>> their > >>>>>>>> > >>>>>>>> > SID assignment scheme in advance of deploying the new scheme. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] For VFA, there would be issue for legacy nodes. I agree. In > >>>>>>>> this case, > >>>>>>>> > >>>>>>>> > solution could be > >>>>>>>> > >>>>>>>> > - either have a fallback plan for newer nodes if > >>>>>>>> detection of legacy nodes > >>>>>>>> > >>>>>>>> > exist in the network. E.g. spawn new CSPF > >>>>>>>> > >>>>>>>> > - or, totally not to deploy VFA unless all nodes are > >>>>>>>> upgraded. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Section 5 is not updated with VFA inclusion. > >>>>>>>> > >>>>>>>> [LES:] My comments have nothing to do with VFA. > >>>>>>>> > >>>>>>>> Please reconsider them after you have understood the backwards > >>>>>>>> compatibility issues. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 3)Virtual Flex Algorithm > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > You have introduced a new concept with very little explanation of > >>>>>>>> what it is > >>>>>>>> > >>>>>>>> > nor how it can be supported. > >>>>>>>> > >>>>>>>> > For example, how would we determine which nodes support a given VFA? > >>>>>>>> > >>>>>>>> > Since the algorithm value must be greater than 255, it cannot be > >>>>>>>> advertised in > >>>>>>>> > >>>>>>>> > the existing SR Algorithm sub-TLV. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > If you are serious about this idea, please provide a > >>>>>>>> more complete > >>>>>>>> > >>>>>>>> > discussion. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] We could illustrate application examples in next > >>>>>>>> presentation. For > >>>>>>>> > >>>>>>>> > ethernet, we have port, and then we have VLAN and stacked vlan. > >>>>>>>> History > >>>>>>>> > >>>>>>>> > has some hints on this. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> [LES:] You are writing a normative specification. Hoping that all > >>>>>>>> readers/implementors have the same "intuition" isn’t sufficient. > >>>>>>>> > >>>>>>>> Les > >>>>>>>> > >>>>>>>> > [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 4)Section 4.3 > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > "R" and "N" flags are now defined in prefix attributes sub-TLV > >>>>>>>> (RFC7794) > >>>>>>>> > >>>>>>>> > They were originally defined in the SR sub-TLV because RFC 7794 > >>>>>>>> did not exist > >>>>>>>> > >>>>>>>> > at the time. > >>>>>>>> > >>>>>>>> > The only reason they continue to exist in RFC 8667 is > >>>>>>>> for backwards > >>>>>>>> > >>>>>>>> > compatibility with early implementation of SR-MPLS based on early > >>>>>>>> drafts of > >>>>>>>> > >>>>>>>> > what became RFC 8667. > >>>>>>>> > >>>>>>>> > Please do not introduce them in new sub-TLVs - there is no need. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] noted with thanks [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > 5)ADJ-SIDs are NOT allocated from the SRGB as they are local in > >>>>>>>> scope. > >>>>>>>> > >>>>>>>> > They MAY be allocated from the SRLB - or outside either GB range. > >>>>>>>> > >>>>>>>> > Please correct the document in this regard. > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > [lc] noted [/lc] > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Les > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > > -----Original Message----- > >>>>>>>> > >>>>>>>> > > From: Lsr <lsr-bounces@ietf.org <mailto:lsr-bounces@ietf.org>> > >>>>>>>> On Behalf Of Acee Lindem > >>>>>>>> > >>>>>>>> > > Sent: Friday, April 7, 2023 11:43 AM > >>>>>>>> > >>>>>>>> > > To: Louis Chan <louisc@juniper.net > >>>>>>>> <mailto:louisc@juniper.net>> > >>>>>>>> > >>>>>>>> > > Cc: lsr <lsr@ietf.org <mailto:lsr@ietf.org>> > >>>>>>>> > >>>>>>>> > > Subject: Re: [Lsr] IETF-116 LSR - IGP extensions for > >>>>>>>> Advertising > >>>>>>>> > >>>>>>>> > > Offset for Flex-Algorithm > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Hi Louis, > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > In the interest of initiating discussion, I would like to > >>>>>>>> propose the > >>>>>>>> > >>>>>>>> > > term "Flex Algorithm Traffic Class (FATC)" for the > >>>>>>>> sub-division of > >>>>>>>> > >>>>>>>> > > flex-algorithm traffic referred to in the draft as “Virtual > >>>>>>>> Flex Algorithm”. > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Also, in your terminology, you refer referred to TLVs and > >>>>>>>> fields with > >>>>>>>> > >>>>>>>> > > simply “Algorithm” when RFC 9350 uses “Flex Algorithm”. > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > Thanks, > >>>>>>>> > >>>>>>>> > > Acee > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> > > _______________________________________________ > >>>>>>>> > >>>>>>>> > > Lsr mailing list > >>>>>>>> > >>>>>>>> > > Lsr@ietf.org <mailto:Lsr@ietf.org> > >>>>>>>> > >>>>>>>> > > > >>>>>>>> > >>>>>>>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/ > >>>>>>>> l > >>>>>>>> s > >>>>>>>> r_ > >>>>>>>> <https://urldefense.com/v3/__https:/www.ietf.org/mailman/listinfo/ > >>>>>>>> l > >>>>>>>> s > >>>>>>>> r_> > >>>>>>>> > >>>>>>>> > > _;!!NEt6yMaO-gk!B9ufrV6k- > >>>>>>>> > >>>>>>>> > c7mtP9JUiXbrF3NCkZ15_UMLBjV_fnJovfz18M5VkkI2F > >>>>>>>> > >>>>>>>> > > EoixpkxsfMnbqwbR0bpHgoS9E$ > >>>>>>>> > >>>>>>>> > > >>>>>>>> > >>>>>>>> > Juniper Business Use Only > >>>>>>>> > >>>>>>>> Juniper Business Use Only > >>>>>>>> > >>>>>>>> > >>>>>>>> Juniper Business Use Only > >>>>>>>> > >>>>>>> > >>>>>>> _______________________________________________ > >>>>>>> Lsr mailing list > >>>>>>> Lsr@ietf.org > >>>>>>> https://urldefense.com/v3/__https://www.ietf.org/mailman/listinfo/l > >>>>>>> s > >>>>>>> r > >>>>>>> __;!!NEt6yMaO-gk!EX4RtSVg7I0jO4M9ZMrtcjGl2sqxcDIFHFZRnk4pocYHUxv9_p > >>>>>>> A > >>>>>>> b > >>>>>>> 8cfeVdGYX_3gOEDi1kljo7ufGA$ > >>>>>>> ------------------------------------------------------------------- > >>>>>>> - > >>>>>>> - > >>>>>>> ---------------------------------------------------------------- > >>>>>>> 本邮件及其附件含有新华三集团的保密信息,仅限于发送给上面地址中列出 > >>>>>>> 的个人或群组。禁止任何其他人以任何形式使用(包括但不限于全部或 > 部分地泄露、复制、 > >>>>>>> 或散发)本邮件中的信息。如果您错收了本邮件,请您立即电话或邮件 > 通知发件人并删除本 > >>>>>>> 邮件! > >>>>>>> This e-mail and its attachments contain confidential information > >>>>>>> from New H3C, which is intended only for the person or entity whose > >>>>>>> address is listed above. Any use of the information contained > >>>>>>> herein in any way (including, but not limited to, total or partial > >>>>>>> disclosure, reproduction, or dissemination) by persons other than > >>>>>>> the intended > >>>>>>> recipient(s) is prohibited. If you receive this e-mail in error, > >>>>>>> please notify the sender by phone or email immediately and delete it! > >>>>>>> > >>>>>> > >>>>>> > >>>>> > >>>>> > >>>>> Juniper Business Use Only > >>>>> > >>>> > >>>> > >>>> Juniper Business Use Only > >>>> > >>> > >>> > >>> Juniper Business Use Only > >>> > >> > >> > >> _______________________________________________ > >> Lsr mailing list > >> Lsr@ietf.org > >> https://www.ietf.org/mailman/listinfo/lsr > >> > >> > >> > >> > >> _______________________________________________ > >> Lsr mailing list > >> Lsr@ietf.org > >> https://www.ietf.org/mailman/listinfo/lsr > >> > > > > > > > > > > > >
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Acee Lindem
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Les Ginsberg (ginsberg)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Les Ginsberg (ginsberg)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… 程伟强
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… linchangwang
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Acee Lindem
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… linchangwang
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… linchangwang
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Les Ginsberg (ginsberg)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Ketan Talaulikar
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Ketan Talaulikar
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Ketan Talaulikar
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Ketan Talaulikar
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Huzhibo
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… linchangwang
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Dongjie (Jimmy)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Les Ginsberg (ginsberg)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Weiqiang Cheng
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Weiqiang Cheng
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Robert Raszuk
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… 程伟强
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Les Ginsberg (ginsberg)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Peter Psenak
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Dongjie (Jimmy)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Dongjie (Jimmy)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Gyan Mishra
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Dongjie (Jimmy)
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Krzysztof Szarkowicz
- Re: [Lsr] IETF-116 LSR - IGP extensions for Adver… Louis Chan