Re: [mpls] Opsdir last call review of draft-ietf-mpls-bfd-directed-27

[Greg Mirsky <[e-mail]>]

Thank you, Joe, for your quick response. I'll upload the updated version
with the updates addressing the TSVART review.

Regards,
Greg

On Mon, Apr 15, 2024 at 3:48 PM Joe Clarke (jclarke) <[e-mail]>
wrote:

> Thanks for the modifications.  They read well to me.  As to the question…
>
>
>
> Finally, my question.  In the Operational Consideration, what would (or
> should)
> happen to the underlying service while the LSP ping is processed in the
> case of
> reverse-path FEC failure?  Is there guidance to provide to maintain service
> while this new session might be established?
>
> GIM>> That, in my opinion, is the formative question; thank you for that.
> It is assumed that the operator controls the network to which the Reverse
> PAth Control TLV is applied. If theat is the case, the failure of the
> installed reverse path is a case of the network failure. The operator, I
> assume that from the ingress BFD peer, is notified, and then can switch the
> reverse path of the BFD session. I imagine, that there could be other
> switchover policies, but I believe that it is essential that the ingress
> BFD peer detects the network failure if the reverse path of the BFD session
> fails. WDYT?
>
>
>
> JMC: I read this differently the first time.  Thinking on your figure, I
> agree with you.  If the tunnel A-B-C-D-G-H is good, but the reverse
> H-G-D-C-B-A is not (and this is the reverse path requested), then we can
> assume there isn’t bidirectional forwarding and the ingress peer should be
> informed.  That likely should warrant a service interruption unless there
> is another viable failover path.
>
>
>
> Joe
>