[lisp] Re: Review draft-ietf-lisp-te

[Luigi Iannone <[e-mail]>]

> On 7 May 2024, at 16:36, Dino Farinacci <[e-mail]> wrote:
> 
> 
>> The text still assumes that an ELP must be returned.
> 
> That is correct.
> 
>> 
>> Just replace the words:
>> 
>>   “which returns a ELP-based locator record for a path to RTR 'y', and encapsulates packets…"
> 
> The example is illustrating nesting so I believe it is not needed.

I understand the example, but the text is a bit misleading because seems to suggest that lookup _must_ return an ELP. 
Anyway, in the last revision is already better.  


> 
>>>>> Luigi, the terms are used in self contained sections. They are fine. S-EID is ONLY used in the multicast section because the is the convention we use to look up a multicast mapping (S-EID, G-EID).
>> 
>> I think a unique term makes more sense, but this is not a blocking point.
> 
> It is a unique term. The term S-EID is used in all the multicast drafts to describe an (S,G).

Fine.

> 
>> This is exactly the point. I do not see an alternate path. I see only an alternate tunnel.
>> The current text is still confusing. You want "to route around the path from B to C” and to do it you route "through link B—>C”. This looks like a contradiction to me.
> 
> B and C have other links. Don’t you see the link between B and X. That is “another” path.

But the figure has no “other path” in it. I added one in my first review but you did not like it.

The text:

if it is desirable to route around the path from B to C through link B-->C, 

Still look like a contradiction. Furthermore, in figure 1 you were already routing through link B—>C, so it looks like you “route around” through the very same link…..



> 
>> The sentence remains superfluous. Of course you can do it with ODL, but this is out of the scope of the IETF and I do not see why it should be there.
>> The other LISP documents never mention a provision system, so why this one has to mention it? Is there a compelling reason?
> 
> Because in other cases ETRs register their own RLOCs because they know them. With an ELP, a provisioning system knows the topology and can register all the addresses in the ELP.  It has a broader view. 
> 
> There are deployments that take an ISIS topology, compute paths offline as an SDN controller, and can build an ELP path based on policy rules (where re-encapsulation points can be placed in the network). 
> 

The sentence is still superfluous. The fact that some LISP deployments use some SDN approach has no place in the document. This is a technical document for implementation of a feature, not a LISP advertisement.
You can leave the sentence there if you really wish, but remains superfluous.


Fix the example and we tackle the text.

Ciao

L.


> Dino