Re: [Lsr] New Version Notification for draft-xu-lsr-flooding-reduction-in-clos-01.txt

I agree with all aforementioned comments.

Wrt AI/ML networking - if a controller is used, what is required is link state exposure northbound and not link state protocol  in the fabric. (I could argue for RIFT though ;-))
I’d urge you to take a look at Meta’s deployment  in their ML clusters (publicly available) - they use BGP as the routing protocol to exchange reachability (and build ECMP sets) and provide a backup if controller computed next hop goes away/before new one has been computed.
Open R is used northbound to expose the topology (in exactly same way - BGP-LS could be used).

To summarize: an LS protocol brings no additional value in scaled-out leaf-spine fabrics, without significant modifications -  it doesn’t work in irregular topologies such as DF, etc.
Existing proposals - there are shipping implementations and experience in operating it, have proven their relative value in suitable deployments.

Cheers,
Jeff

> On Nov 26, 2023, at 12:20, Acee Lindem <acee.ietf@gmail.com> wrote:
> 
> Speaking as WG member:
> 
> I agree. The whole Data Center IGP flooding discussion went on years ago and the simplistic enhancement proposed in the subject draft is neither relevant or useful now.
> 
> Thanks,
> Acee
> 
>> On Nov 24, 2023, at 11:55 PM, Les Ginsberg (ginsberg) <ginsberg=40cisco.com@dmarc.ietf.org> wrote:
>> 
>> Xiaohu –
>> I also point out that there are at least two existing drafts which specifically address IS-IS flooding reduction in CLOS networks and do so in greater detail and with more robustness than what is in your draft:
>> https://datatracker.ietf.org/doc/draft-ietf-lsr-distoptflood/
>> https://datatracker.ietf.org/doc/draft-ietf-lsr-isis-spine-leaf-ext/
>> I do not see a need for yet another draft specifically aimed at CLOS networks.
>> Note that work on draft-ietf-lsr-isis-spine-leaf-ext was suspended due to lack of interest in deploying an IGP solution in CLOS networks.
>> You are suggesting in draft-xu-lsr-fare that AI is going to change this. Well, maybe, but if so I think we should return to the solutions already available and prioritize work on them.
>>    Les
>>  From: Lsr <lsr-bounces@ietf.org> On Behalf Of Tony Li
>> Sent: Thursday, November 23, 2023 8:39 AM
>> To: xuxiaohu_ietf@hotmail.com
>> Cc: lsr@ietf.org
>> Subject: Re: [Lsr] New Version Notification for draft-xu-lsr-flooding-reduction-in-clos-01.txt
>> Hi,
>> What you’re proposing is already described in IS-IS Mesh Groups (https://www.rfc-editor.org/rfc/rfc2973.html) and improved upon in Dynamic Flooding (https://datatracker.ietf.org/doc/html/draft-ietf-lsr-dynamic-flooding).
>> Regards,
>> Tony
>> 
>> 
>> On Nov 23, 2023, at 8:29 AM, xuxiaohu_ietf@hotmail.com wrote:
>> Hi all,
>> Any comments or suggestions are welcome.
>> Best regards,
>> Xiaohu
>> 发件人: internet-drafts@ietf.org <internet-drafts@ietf.org>
>> 日期: 星期三, 2023年11月22日 11:37
>> 收件人: Xiaohu Xu <xuxiaohu_ietf@hotmail.com>
>> 主题: New Version Notification for draft-xu-lsr-flooding-reduction-in-clos-01.txt
>> A new version of Internet-Draft draft-xu-lsr-flooding-reduction-in-clos-01.txt
>> has been successfully submitted by Xiaohu Xu and posted to the
>> IETF repository.
>> 
>> Name:     draft-xu-lsr-flooding-reduction-in-clos
>> Revision: 01
>> Title:    Flooding Reduction in CLOS Networks
>> Date:     2023-11-22
>> Group:    Individual Submission
>> Pages:    6
>> URL:      https://www.ietf.org/archive/id/draft-xu-lsr-flooding-reduction-in-clos-01.txt
>> Status:   https://datatracker.ietf.org/doc/draft-xu-lsr-flooding-reduction-in-clos/
>> HTMLized: https://datatracker.ietf.org/doc/html/draft-xu-lsr-flooding-reduction-in-clos
>> Diff:     https://author-tools.ietf.org/iddiff?url2=draft-xu-lsr-flooding-reduction-in-clos-01
>> 
>> Abstract:
>> 
>>   In a CLOS topology, an OSPF (or ISIS) router may receive identical
>>   copies of an LSA (or LSP) from multiple OSPF (or ISIS) neighbors.
>>   Moreover, two OSPF (or ISIS) neighbors may exchange the same LSA (or
>>   LSP) simultaneously.  This results in unnecessary flooding of link-
>>   state information, which wastes the precious resources of OSPF (or
>>   ISIS) routers.  Therefore, this document proposes extensions to OSPF
>>   (or ISIS) to reduce this flooding within CLOS networks.  The
>>   reduction of OSPF (or ISIS) flooding is highly beneficial for
>>   improving the scalability of CLOS networks.
>> 
>> 
>> 
>> The IETF Secretariat
>> 
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