Thank you Jie.

Once I have a an initial draft together I will send it over to you before I
submit.

Thank you

Gyan


On Sun, Jun 7, 2026 at 11:40 PM Dongjie (Jimmy) <[email protected]> wrote:

> Hi Gyan,
>
>
>
> Sorry for the late response. Thanks a lot for your shepherd review and the
> valuable view on the migration and deployment of SR based NRPs in
> production networks.
>
>
>
> Your suggestion of adding operational considerations for the migration
> case makes sense to me, and it would helpful to operators who may want to
> migrate their SR deployments to NRP-capable.
>
>
>
> A new version will be produced to incorporate your suggestions.
>
>
>
> Best regards,
>
> Jie (on behalf of co-authors)
>
>
>
> *From:* Gyan Mishra <[email protected]>
> *Sent:* Thursday, May 14, 2026 1:16 PM
> *To:* SPRING WG <[email protected]>; spring-chairs <[email protected]>;
> [email protected]; Dongjie (Jimmy) <
> [email protected]>; Alvaro Retana <[email protected]>
> *Subject:* draft-ietf-spring-sr-for-enhanced-vpn-10 ; Shepherd Review
>
>
>
>
>
> All
>
>
>
> I have completed the Shepherd review for this draft.
>
>
>
> https://datatracker.ietf.org/doc/draft-ietf-spring-sr-for-enhanced-vpn/
>
>
>
> I would like to open up a discussion on this draft and its importance to
> SR architecture with respect to network slicing and one of the major use
> cases being for 5G Mobile core cloud native fabric URLLC low latency slice
> and high bandwidth slice NRP.
>
>
>
> This draft presents an exciting critical milestone for Spring WG related
> to SR technology with our official first SR use case for resource aware
> segments draft below which is now in queue for publication.
>
>
>
> https://datatracker.ietf.org/doc/draft-ietf-spring-resource-aware-segments/
>
>
>
> The base concept behind a resource Sid is that the topological SIDs both
> the prefix SID and adjacency SID are now resource aware for forwarding
> packets.  These new resource aware Sid are allocated with set of network
> resources such as buffers, queues and bandwidth for all links that are part
> of the associated NRP topology.  This could be a flex algo plane or dynamic
> SR policy using TEDs Algo 0.
>
>
>
> Most all vendors have limits to the maximum number of flex algo planes
> that the NOS supports based on platform.  This is due to hardware resource
> constraints with cSPF per flex algo plane IETF technology for instantiating
> the NRP.
>
>
>
> In the discussion think about SRv6 and how H-QOS can be used with Flex
> Algo match on SRv6 locator and can have link coloring with multiple flex
> algo bit positions on a link encoded in AG/EAG in ASLA and now with HQOS
> parent shaper can provide guaranteed bandwidth per locator Gold, Bronze and
> Silver allocation of a pecking order per Flex algo NRP.  This example is a
> real world scenario and I have deployed as such in a production environment
> and works well.
>
>
>
> So now take the concept of resource aware SIDs and how are we getting a
> more granular enhancement in discrete buffers, queues and bandwidth over
> and above the scenario I mentioned above.
>
>
>
> Note that if you have complete isolation disjoint planes then IETF network
> slicing does not come into play.  However that is rare and does not scale
> and most cases are shared paths by operators.
>
>
>
> With the industry direction moving in a large way towards massive super
> highways on the global internet by Tier-1 and Tier-2 and MNO providers,
> with POI (camp wg) bandwidth on demand p2p dark fiber or lit DWDM links
> with coherent pluggable ZR / ZR+ optics you can have 64 wavelengths on a
> single fiber.  The wavelength channels in this use case can be placed on
> sub interfaces disaggregated and each or set of wavelengths can map to a
> flex algo or algo 0 TEDs plane or Flexe could be used for the NRP paths.
> This could be a major use case for Enhanced VPN using resource aware SIDs.
>
>
>
>
> During a migration there could existing provisioned non resource aware
> Sid’s such as for flex algo 128 prefix Sid provisioning.  At the same time
> when new resource aware Sids are deployed for an existing flex algo
> topology with prefix Sids that are not resource aware, you now have a
> situation of double booking provisioning of resources cSPF per flex algo.
> This double booking goes against the vendor platform maximum supported.
>
>
>
> I mentioned in my Shepherds review of an alternative solution which I will
> work with Jie as co-author of a new draft I will spin up which provides an
> resource aware extension to existing topological SIDs to avoid double
> booking of resources during migration.  As well as migration simplification
> by enabling a resource knob on the topological Sid to make it resource
> aware.
>
>
>
> I would like to discuss with the WG both options and compare and contrast
> and feedback for both solutions on this thread.
>
>
>
> As this is a very real world use case,  I am interested in operator
> feedback on the usefulness of resource aware Sid’s for Enhanced VPN use
> case. and is it something that will be deployed in production.
>
>
>
> Please respond to this thread on any feedback related to my review and any
> questions or comments related to operational considerations.
>
>
>
> Kind Regards
>
>
>
> Gyan
>
>
>
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