Re: [Lsr] Erik Kline's Discuss on draft-ietf-lsr-isis-srv6-extensions-14: (with DISCUSS)

[Peter Psenak <[e-mail]>]

Hi Erik,

thanks for your comment, please see inline:

On 19/05/2021 03:58, Erik Kline via Datatracker wrote:
> Erik Kline has entered the following ballot position for
> draft-ietf-lsr-isis-srv6-extensions-14: Discuss
> 
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> 
> ----------------------------------------------------------------------
> DISCUSS:
> ----------------------------------------------------------------------
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> [ section 9 ]
> 
> * I share the concerns of several of the others here about SRv6 SIDs being
>    claimed to be IPv6 addresses but kinda not really being IPv6 addresses
>    if their internal structure is exposed outside of the given SR router.


SRv6 SIDs are indeed IPv6 addresses. RFC8986 introduced the SRv6 SID 
structure. It also goes into allocation of SIDs where it describes the 
carving out of the Block for SRv6 SIDs in the domain, followed by the 
allocation of SRv6 Locators to the nodes in the domain. Then the node 
allocates the function part when instantiating the SID - and all of this 
is signaled via control plane protocols. This is all exposed and know to 
the operator who determines the addressing scheme.


> 
>    If "[i]t's usage is outside of the scope of this document", can this be
>    removed for now, and maybe take up the issue at some point in the future
>    by which time a motivating use case might have presented itself?


The use-cases have not been described in this document since they were 
out of the scope of the ISIS protocol operations. Some of the use-cases 
discussed have been :

- automation and verification of blocks/locators and setup of filtering 
for them at SR domain boundaries

- validation of SRv6 SIDs being instantiated and advertised via IGP; 
these can be learnt by apps/controllers via BGP-LS and then monitored 
for conformance to the addressing rules set by the operator.

- verification and even determination of summary routes to be used for 
covering the SRv6 Locators and SIDs.

There may be other use-cases that may be operator or vendor specific. 
The use-cases are not within the scope of ISIS protocol extensions and 
are either operational or implementation specific – hence we said it was 
out of the scope of this document.

If you feel adding these to the document may help to clear your 
concerns, I can certainly add them.

thanks,
Peter




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