Robert –

Your comments are many years late. 😊

Things like TE, Segment Routing, flex-algo were incorporated into the protocol 
years ago.
Critiquing the transport because it is being extended to meet the requirement 
of functionalities that have been standardized is not sensible.
If you want to argue these functionalities should be removed from the protocol 
– well, that’s at least a logical approach – though I don’t think the WG or the 
industry is interested in such a change.

One of the legitimate criticisms of having the IGP carry information not used 
by the protocol itself is that it is present on all nodes when it only needs to 
be used for a subset of the nodes.
But that argument doesn’t apply here.

   Les


From: Robert Raszuk <rob...@raszuk.net>
Sent: Friday, November 1, 2024 8:44 AM
To: Les Ginsberg (ginsberg) <ginsb...@cisco.com>
Cc: Henk Smit <henk.i...@xs4all.nl>; lsr@ietf.org; Hannes Gredler 
<han...@gredler.at>
Subject: Re: [Lsr] Re: Using RFC 7356 to address TLV size limitations


> It is required because we have a need for more than 255 bytes of data 
> directly used by the protocol.

Seems pretty clear that we have differences of opinion in classification of 
stuff which went into the protocol in the recent decade to be really needed by 
routing or perhaps used by various optional optimisations on top of base 
topology.

For example - numerous extensions for TE use purposes (and the list is growing 
...) - are those really something which should be flooded to each node domain 
wide just because flooding is already there so let's use it ? Should elements 
used for computation of constrained paths be part of base routing protocol ? 
Same for building constrained topologies ...

Each such atomic extension looks small and innocent, but when you have to pack 
all of them together things get oversized.


On Fri, Nov 1, 2024 at 4:12 PM Les Ginsberg (ginsberg) 
<ginsb...@cisco.com<mailto:ginsb...@cisco.com>> wrote:
Robert –

The need for more than 255 bytes/TLV in this case has nothing to do with 
“non-routing-protocol-data”. It is required because we have a need for more 
than 255 bytes of data directly used by the protocol.

Please do not conflate this with issues related to requests for the IGPs to 
carry data not used by the protocol itself.

   Les

From: Robert Raszuk <rob...@raszuk.net<mailto:rob...@raszuk.net>>
Sent: Friday, November 1, 2024 2:35 AM
To: Les Ginsberg (ginsberg) <ginsb...@cisco.com<mailto:ginsb...@cisco.com>>
Cc: Henk Smit <henk.i...@xs4all.nl<mailto:henk.i...@xs4all.nl>>; 
lsr@ietf.org<mailto:lsr@ietf.org>; Hannes Gredler 
<han...@gredler.at<mailto:han...@gredler.at>>
Subject: [Lsr] Re: Using RFC 7356 to address TLV size limitations

Thx Les !

I asked this 2nd time as IMO direction towards growing TLV sizes is not the 
best solution.

Especially for opaque to routing information which applies to (tiny) subset of 
link state nodes in the IGP domain.

See if you keep bringing larger and larger trucks folks will happily keep 
loading stuff (not to say junk) on them.

I would very much prefer that we consider solutions like DROID 
(draft-li-lsr-droid) or any other pub-sub message bus for this type of 
information distribution instead of keep running on existing flooding.

Many thx,
Robert

On Fri, Nov 1, 2024 at 1:28 AM Les Ginsberg (ginsberg) 
<ginsb...@cisco.com<mailto:ginsb...@cisco.com>> wrote:
Robert –

The fact that we have a 16 bit length does not mean we can actually send a 
single TLV of length 65K bytes – nor do we need to do so.

The protocol is still limited by whatever the lsp-mtu in the deployment is – 
which is required to be <= the minimum MTU of all links in the network enabled 
for IS-IS.

References to RFC 5311 are in the context of needing more than 256 
LSPs/node/level – not in the context of 16 bit TLVs.

   Les


From: Robert Raszuk <rob...@raszuk.net<mailto:rob...@raszuk.net>>
Sent: Thursday, October 31, 2024 5:16 PM
To: Les Ginsberg (ginsberg) <ginsb...@cisco.com<mailto:ginsb...@cisco.com>>
Cc: Henk Smit <henk.i...@xs4all.nl<mailto:henk.i...@xs4all.nl>>; 
lsr@ietf.org<mailto:lsr@ietf.org>; Hannes Gredler 
<han...@gredler.at<mailto:han...@gredler.at>>
Subject: Re: [Lsr] Using RFC 7356 to address TLV size limitations

Dear Les,


Issue #2 is the limited size of a single TLV/sub-TLV.

This is addressed by using 16 bit type/length fields.

Can you please kindly elaborate how you fit 65K octet TLV into 9K octets of 
jumbo frames (max practical MTU) on a link used for flooding between any two 
nodes ?

RFC7356 says go and read RFC5311 on how to do that. Well can you pls point me 
to a section of RFC5311 which explains how to do it? My reading of it leads me 
to believe that it very well describes how to get around the 256 LSP limit. But 
not how to fit an elephant into a rope bridge.

Thx,
Robert
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