Re: [spring] Queries regarding SRV6-micro-SID

[Bharath R <[e-mail]>]

Thanks Pablo for your clarifications!!!



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From: Pablo Camarillo (pcamaril) <[e-mail]>
Sent: Wednesday, June 15, 2022 2:09 PM
To: Bharath R <[e-mail]>
Cc: [e-mail]
Subject: RE: Queries regarding SRV6-micro-SID

[External Email. Be cautious of content]

Hi Bharath,

See inline with [PC].

Thanks,
Pablo.

From: Bharath R <[e-mail]<mailto:[e-mail]>>
Sent: martes, 14 de junio de 2022 2:34
To: [e-mail]<mailto:[e-mail]>; Pablo Camarillo (pcamaril) <[e-mail]<mailto:[e-mail]>>
Subject: Queries regarding SRV6-micro-SID

Hi,
I have following queries on draft https://datatracker.ietf.org/doc/draft-filsfils-spring-net-pgm-extension-srv6-usid/12/<https://urldefense.com/v3/__https:/datatracker.ietf.org/doc/draft-filsfils-spring-net-pgm-extension-srv6-usid/12/__;!!NEt6yMaO-gk!EyUViIeGcOhKfcVYj6GJR9XzSxhu1dFN4uwIgjkdqBFr3_wiL-HwbrfRRfwG7CL9_1Okdztplqmr_7heKg$>, section 3.1.3

Query1:
Regarding section 3.1.3
More specifically, a uSID is allocated from the GIB or LIB of
      block 2001:db8:0::/48 depending on the value of the "X" nibble:
      0-D for GIB, and E-F for LIB.

I wanted to understand if this nibble allocation of 0-D for GIB and E-F for LIB is for illustration purposes only or can these be configurable values so that a network administrator can have more flexibility?
[PC] Illustration purposes. (Section is titled "Reference Illustration"). Boundary is configured by the network administrator.
For e.g. Having more LIB can have the flexibility of having more uDt(more service SIDs). Yes, this means they'll have less uN(Node SIDs), but they may be O.K. with it for their deployment.
Of course, this will mean that the same nibble allocation will have to be provisioned on all the nodes in the domain.
[PC] Correct.


Query2:
Can a network have a mixed deployment of 16-bit and 32-bit compressions?
The ingress will know whether the SIDs are 16-bit or 32 bit, and also the actual transit nodes that need to process these SIDs, can have the local routes programmed appropriately. I don't think there are challenges here.
However, there may be challenges regarding GIB and LIB nibble allocation.
Since GIB and LIB need to come from different ranges, one might have to configure such that all the GIBs come withing the 16-bit range(with some left over for LIBs) or vice-versa.
[PC] Yes, indeed. We will clarify this in the next revision of the draft.

Query3:
Can there be a deployment where some SR-capable nodes support normal-SRV6 and other support compressed-SRV6-SIDs.
[PC] Yes.
Say a TI-LFA path needs to traverse Nodes A, Node B, Node C, should a computing nod consider the possibility that node A and C support compression, but node B doesn't


Thanks and regards,
Bharath R.


Thanks, and regards,
Bharath R.

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