On Wed, 17 Jun 2020 at 18:42, Saku Ytti <saku@ytti.fi> wrote:

Hey,

> Why do we really need SR? Be it SR-MPLS or SRv6 or SRv6+?

I don't like this, SR-MPLS and SRv6 are just utterly different things
to me, and no answer meaningfully applies to both.

I don't understand the point of SRv6. What equipment can support IPv6 routing, but can't support MPLS label switching?

I'm a big fan of SR-MPLS however.

And we get more features to boot, with LDP if you want LFA, you need
to form tLDP to every Q-space node, on top of your normal LDP, because
you don't know label view from anyone else but yourself. With SR by
nature you know the label view for everyone, thus you have full LFA
coverage for free, by-design.

Not just this, but the LFA path is always the post-convergence path. You don't get microloops.

You can implement TE on top if that is your thing. No need to run RSVP. Another protocol you don't need to run.

You don't need to throw out all your old kit, and replace with new in one go. You can incrementally roll it out, and leave islands of LDP where needed. LDP-SR interworking is pretty simple.

We are currently introducing it into our core. It will probably be a while before we fully phase out LDP, but its definitely on the roadmap.

Regards,

Dave