[spring] Re: Question for the working group

[Tony Li <[e-mail]>]

> On Mar 6, 2026, at 9:25 AM, Joel Halpern - jmh.direct at joelhalpern.com <[e-mail]> wrote:
> 
> In regard to Segment Routing Policy as defined by RFC 9256 and the MPLS Network Action (MNA) work that is being standardized by the MPLS working group, please express an opinion as to whether:
> 
> 1) An MNA Substack may never be considered a segment in the sense of RFC 9256 section 4;
> 
> 2) Some MNA substacks may be considered segments in the sense of RFC 9256 Section 4 (possibly with a new segment type, possibly with an existing segment type)
> 
> 3) MNA substacks are segments in the sense of RFC 9256 section 4 (possibly with a new segment type, possibly with an existing segment type)


An MNA ISD Substack is a set of LSEs. It contains no forwarding labels. To my read, it does not fall into any of the types currently defined in RFC 9256 section 4.

Whether or not we want to declare a new segment type is of course up to the WG, and depends entirely on whether there is benefit to doing so.  I am not yet convinced that there is benefit, but am open to constructive arguments.

Regards,
Tony