Re: [Isis-wg] [spring] Handling same SID mapped to different prefixes and vice versa cases

[Robert Raszuk <[e-mail]>]

Hi Pushpasis
​,


*[Pushpasis] No. I seem to be repeating myself. But your suggestion of
recursing will result in tunnelling traffic destined for all prefixes
originated (not only loopback addresses) though MPLS. Operator may not
like/want this. So associating the sid-index with the loopback address
with a specific address provides flexibility in picking which prefixes
should be tunneled and which ones need not.*
>
>
​I do not quite agree with your above statement. Clearly you are thinking
in terms how traditional MPLS router with perhaps specific implementation
resolves paths and building forwarding tables in MPLS domain.

Let's observe that Segment Routing imposition may but not necessarily must
use the same imposition algorithm/mechanism.

​I can easily see a case at ingress where only carefully selected by
operator subset of prefixes originated by exit X will be MPLS segment
routed in the given domain. Rest may be native switched or IP
tunneled/encapsulated.

As examples that can be accomplished by controller driven ingress map or
use multiple next hops (the case where you propagate by BGP).

Cheers,
R.