Hi Huaimo,

The first draft builds on existing mechanisms and procedures. The second draft 
is redundant and adds no value whatsoever.

Regards,
Tony


> On Mar 26, 2023, at 3:40 AM, Huaimo Chen <[email protected]> wrote:
> 
> Hi Les,
> 
>     Thanks much for your comments.
>     My responses are inline below with HC.
> 
> Best Regards,
> Huaimo
> From: Les Ginsberg (ginsberg) <[email protected] <mailto:[email protected]>>
> Sent: Thursday, March 23, 2023 3:35 AM
> To: [email protected] <mailto:[email protected]> <[email protected] <mailto:[email protected]>>; 
> [email protected] 
> <mailto:[email protected]> 
> <[email protected] 
> <mailto:[email protected]>>
> Subject: Comments on draft-chen-lsr-isis-big-tlv-00
>  
> Folks -
>  
> This draft proposes a new way to handle advertisement of more than 255 bytes 
> of information about a given object.
> It defines a new "container TLV" to carry additional information about an 
> object beyond the (up to) 255 bytes of information advertised in an existing 
> TLV.
>  
> The draft is defining a solution to a problem which has already been 
> addressed without requiring any protocol extensions. 
> [HC]: It seems that a protocol includes a set of procedures. Would you mind 
> telling me which existing protocols can be used to resolve the problem 
> without requiring any protocol extensions?
> 
> The existing solution - discussed in 
> https://datatracker.ietf.org/doc/draft-pkaneria-lsr-multi-tlv/ 
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fdatatracker.ietf.org%2Fdoc%2Fdraft-pkaneria-lsr-multi-tlv%2F&data=05%7C01%7Chuaimo.chen%40futurewei.com%7C6e9af0fb3bcd4bef57a408db2b7125a4%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C638151537195561122%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=23RCLltpVh%2BmKSaVzz6v%2FprNKtUU%2Bqx0FEik6x7qvHs%3D&reserved=0>
>  has already been successfully implemented and deployed by multiple vendors.
> [HC]: You are a co-author of this draft, called a first draft for resolving 
> the problem on big TLVs. This first draft contains some protocol extensions. 
> If there is a solution for the problem without requiring any protocol 
> extensions, then why do you as a co-author work on the first draft with 
> protocol extensions?
> 
> The definition of a second solution to the problem is not needed - and in 
> fact further complicates both implementation and deployment. Should the 
> existing solution be used? Should the new solution be used? What is the state 
> of support by all nodes in the network for each solution?
> [HC]:  It seems better to merge the two drafts (i.e., the first draft and the 
> second draft defining container TLV) into one. 
>  
> The motivation for the new solution seems to be the notion that it supports 
> partial deployment. Text in 
> https://www.ietf.org/archive/id/draft-chen-lsr-isis-big-tlv-00.html#name-incremental-deployment
>  
> <https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.ietf.org%2Farchive%2Fid%2Fdraft-chen-lsr-isis-big-tlv-00.html%23name-incremental-deployment&data=05%7C01%7Chuaimo.chen%40futurewei.com%7C6e9af0fb3bcd4bef57a408db2b7125a4%7C0fee8ff2a3b240189c753a1d5591fedc%7C1%7C0%7C638151537195561122%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=AwI4YHL1uPDwbqPoCtjvobS424RT3OGNWdUxM9XclUY%3D&reserved=0>
>   states:
>  
> "For a network using IS-IS, users can deploy the extension for big TLV in a 
> part of the network step by step.
> The network has some nodes supporting the extension (or say new nodes for 
> short) and the other nodes not
> supporting the extension (or say old nodes for short) before the extension is 
> deployed in the entire network."
>  
> This suggests the authors believe that a network can function with some nodes 
> using all of the advertisements and some nodes using only the legacy 
> advertisements, but this is obviously false.
> Fundamental to operation of a link state protocol is that all nodes in the 
> network operate on identical LSPDBs.
> The suggestion that features will work correctly when some nodes use 
> attributes advertised in legacy TLVs and the new container TLV while some 
> nodes use only the attributes advertised in legacy TLVs is simply incorrect.
> [HC]: Every node in the network has the same LSPDB. The new nodes understand 
> the new container TLVs and may use them. The old nodes do not understand them 
> and do not use them.
>  
> It is also important to also state that the advertisement of more than 255 
> bytes of information is driven by configuration – not a protocol 
> implementation choice. Suppressing advertisement of some of the configured 
> information also does not result in a working network.
>  
> In short, there is no positive value from the proposed extension – and it 
> does harm by further complicating implementations and deployments.
> [HC]: The second draft defines a general mechanism for resolving the problem. 
> It is backward compatible and simple.  It does not do any harm.
>  
> The draft should be abandoned.
>  
>     Les
>  
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