Re: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH

["Wang, Weibin (NSB - CN/Shanghai)" <[e-mail]>]

Hi Ron,

After reading through many mails related to CRH in list, I found all CRH-SIDs (allocated to prefix-sid <loosely forwarding>and Adj-sid<strict forwarding>) are of local significance in fact, its operation actually is not same as MPLS Label nor SR-MPLS label (such as domain-wide prefix SID/label), all CRH-SIDs are locally allocated by node itself based on local FIB6, independent of other CRH-SID allocated by other nodes in CRH domain; so every node (Maybe except  ingress PE of CRH domain)  has no useful to learn other SIDs allocated by other nodes by IGP-extension advertising. Its deployment must have controller (considering dynamic mechanism), the controller learn all CRH-SIDs from each node to program the source path under path calculation requirement from ingress PE.

I suggested you should describe more detail about how to create CRH-SID entry (in CRH-FIB) in this CRH draft, is it based on local FIB6, if it is, how to do synchronization between CRH-FIB and FIB6?
Above is my understanding, if not right,pls correct me.

Wang Weibin

From: ipv6 <[e-mail]> On Behalf Of Ketan Talaulikar (ketant)
Sent: 2020年5月28日 19:46
To: Ron Bonica <rbonica=[e-mail]>; Joel M. Halpern <[e-mail]>
Cc: [e-mail]; [e-mail]; 6man <[e-mail]>
Subject: RE: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH


Hi Ron,



Some of the operators may not care about the SR name, but it is clear to me that the proposal in the CRH draft is a subset of Segment Routing (i.e. a reduced portion of Spring Architecture) that only supports prefix and adjacency SIDs as indicated by the two "forwarding methods".



https://tools.ietf.org/html/draft-bonica-6man-comp-rtg-hdr-22#section-4


   o  Forward the packet to the next-hop along the least-cost path to >>> Prefix SID
      the next segment endpoint.

   o  Forward the packet through a specified interface to the next >>> Adjacency SID
      segment endpoint.



Given the use of mapping IDs and mapping FIB, the proposal is comparable more to SR-MPLS than SRv6. It is better to do a holistic analysis of any proposal such as CRH that is introducing an MPLS label like mapping construct into IPv6 architecture - doing so should be considered as a significant change to IPv6.



Thanks,

Ketan



-----Original Message-----

From: Ron Bonica <rbonica=[e-mail]<mailto:rbonica=[e-mail]>>

Sent: 25 May 2020 21:14

To: Ketan Talaulikar (ketant) <[e-mail]<mailto:[e-mail]>>; Joel M. Halpern <[e-mail]<mailto:[e-mail]>>

Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; 6man <[e-mail]<mailto:[e-mail]>>

Subject: RE: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH



Ketan,



It would not be fair to say that these operators  "wish to deploy a Traffic Engineering solution using a subset of Segment Routing".



It would be fair to say that these operators  "wish to deploy IPv6 Traffic Engineering".  Some of these operators don't care about SR. Some are actively averse to SRv6. All they want is a Routing header.



                                                                 Ron















Juniper Business Use Only



-----Original Message-----

From: Ketan Talaulikar (ketant) <ketant=[e-mail]<mailto:ketant=[e-mail]>>

Sent: Monday, May 25, 2020 5:21 AM

To: Ron Bonica <[e-mail]<mailto:[e-mail]>>; Joel M. Halpern <[e-mail]<mailto:[e-mail]>>

Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; 6man <[e-mail]<mailto:[e-mail]>>

Subject: RE: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH



[External Email. Be cautious of content]





Hi Ron,



Thanks for that clarification.



I note that you are not anymore saying "Are not interested in SR" like you had mentioned before the WG adoption call : https://urldefense.com/v3/__https://mailarchive.ietf.org/arch/msg/ipv6/LheyFD_uwuHp7tiG8Y1CwKngDYI/__;!!NEt6yMaO-gk!X2qW2zTZEbZRfBSE6c_KM-k7aIvZTIT9bycp3jyFJ3sTbf8MtGo4E_uGX7zYZ7lk$<https://urldefense.com/v3/__https:/mailarchive.ietf.org/arch/msg/ipv6/LheyFD_uwuHp7tiG8Y1CwKngDYI/__;!!NEt6yMaO-gk!X2qW2zTZEbZRfBSE6c_KM-k7aIvZTIT9bycp3jyFJ3sTbf8MtGo4E_uGX7zYZ7lk$>



So, would it be fair to say that the operator that you are referring to below, wishes to deploy a Traffic Engineering solution using a subset of Segment Routing (i.e. a reduced portion of Spring Architecture) that only supports prefix and adjacency SIDs as indicated by the two "forwarding methods" that are referred to in draft-bonica-6man-comp-rtg-hdr?



Thanks,

Ketan



-----Original Message-----

From: Ron Bonica <rbonica=[e-mail]<mailto:rbonica=[e-mail]>>

Sent: 25 May 2020 09:03

To: Ketan Talaulikar (ketant) <[e-mail]<mailto:[e-mail]>>; Joel M. Halpern <[e-mail]<mailto:[e-mail]>>

Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; 6man <[e-mail]<mailto:[e-mail]>>

Subject: RE: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH



Ketan,



Please consider an operator who:



- Wants a way to steer IPv6 packets through a specified path that includes many nodes (>8)

- Does not want any of the following:

        - A new VPN encapsulation technique

        - A new service function chaining technique

        - Network programming

        - MPLS and uSID

        - To encoding instructions in IPv6 addresses.



These operators want a compact routing header, nothing more.



                                                                           Ron





Juniper Business Use Only



-----Original Message-----

From: ipv6 <[e-mail]<mailto:[e-mail]>> On Behalf Of Ketan Talaulikar (ketant)

Sent: Sunday, May 24, 2020 1:42 AM

To: Joel M. Halpern <[e-mail]<mailto:[e-mail]>>

Cc: [e-mail]<mailto:[e-mail]>; [e-mail]<mailto:[e-mail]>; 6man <[e-mail]<mailto:[e-mail]>>

Subject: RE: [spring] CRH is back to the SPRING Use-Case - Re: Size of CR in CRH



[SNIP]



I am looking for explanation of the "other ways" that CRH can be used (i.e. those outside the Spring architecture). I am trying to understand from the authors what would be the applicability of that solution, it's use-cases and it's requirements. That is what, I believe, will help us evaluate the CRH proposal in the context of this working call. That will help us answer these questions like the scope of the SID, 32-bit or 16-bit or something else and what the CRH-FIB is going to turn out like.





[SNIP]

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