Devil's Advocate - Segment Routing, Why?

Sun Jun 21 21:01:03 UTC 2020

> Wouldn't T-LDP fix this, since LDP LFA is a targeted session?

Nope. You need to get to PQ node via potentially many hops. So you need to
have even ordered or independent label distribution to its loopback in
place.

Best,
R.

On Sun, Jun 21, 2020 at 10:58 PM Mark Tinka <mark.tinka at seacom.mu> wrote:

>
>
> On 21/Jun/20 22:21, Robert Raszuk wrote:
>
>
> Well this is true for one company :) Name starts with j ....
>
> Other company name starting with c - at least some time back by default
> allocated labels for all routes in the RIB either connected or static or
> sourced from IGP. Sure you could always limit that with a knob if desired.
>
>
>
> Juniper allocates labels to the Loopback only.
>
> Cisco allocates labels to all IGP and interface routes.
>
> Neither allocate labels to BGP routes for the global table.
>
>
>
> The issue with allocating labels only for BGP next hops is that your
> IP/MPLS LFA breaks (or more directly is not possible) as you do not have a
> label to PQ node upon failure.  Hint: PQ node is not even running BGP :).
>
>
> Wouldn't T-LDP fix this, since LDP LFA is a targeted session?
>
> Need to test.
>
>
>
> Sure selective folks still count of "IGP Convergence" to restore
> connectivity. But I hope those will move to much faster connectivity
> restoration techniques soon.
>
>
> We are happy :-).
>
> Mark.
>
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