Re: [spring] WG Adoption Call for draft-dong-spring-sr-for-enhanced-vpn

Tarek Saad <> Sat, 25 July 2020 18:57 UTC

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From: Tarek Saad <>
To: James Guichard <>, "" <>
CC: "" <>
Thread-Topic: [spring] WG Adoption Call for draft-dong-spring-sr-for-enhanced-vpn
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Subject: Re: [spring] WG Adoption Call for draft-dong-spring-sr-for-enhanced-vpn
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Hi WG,

This document is touching important topics regarding forwarding on specific set of resources in the network (such as those that define a network slice).
For this, it’s important to be able to identify transiting traffic as belonging to a specific slice so as to impose the specific behavior upon forwarding the traffic on the associated resources.

This draft is proposing to allocate/assign different labels/SIDs (per topological element – either node or link) to identify the specific resource per slice and the respective forwarding behavior.
This may work for smaller networks (and for limited number of slices), but there are concerns that it would run into scale problems (related to # of required labels to allocate and amount of IGP state required for the different SIDs) - as number of topological elements in the network grows and number of vertical/ horizontal slices grows.

It might be useful to define a mechanism by which specific allocated resources for a given link or node are to be identified and not describe how virtual network topologies are to be constructed. This is because the topologies are not necessarily virtual and because there are a multiplicity of uses for this mechanism beyond constructing subsets of the underlay network topology.

We believe encoding the slice identifier separate from the forwarding instruction can yield better scale and still allow for steering on the specific resource. We intend to publish something along those lines in the coming next couple of weeks to gather more feedback.


From: spring <> on behalf of James Guichard <>
Date: Wednesday, July 15, 2020 at 7:17 AM
To: "" <>
Cc: "" <>
Subject: [spring] WG Adoption Call for draft-dong-spring-sr-for-enhanced-vpn

Dear WG:

This email begins a 2 week WG adoption call for ending Wednesday 29th July 2020.

Please speak up if you support or oppose adopting this document into the WG. Please also provide comments/reasons for that support (or lack thereof). Silence will not be considered consent.


Jim, Joel & Bruno