Hi Bruno,

I haven't seen a reply from Pavan, so let me jump in...

>
> I can give a simple distributed TE application example (there are several,
> but this should give a general idea how this information can be leveraged).
> In RSVP-TE networks, a TE path computed using a specific snapshot of TED
> can get rejected during signaling by a transit node because of bandwidth
> unavailability on a specific link (link bandwidth information in the
> snapshot of TED used during computation cannot always be “current”). When
> ingress gets notified of this “error” via RSVP signaling, the link in
> question is avoided in the subsequent path computation and an alternate
> path is sought. Most implementations tend to use a configurable “hold time”
> to determine how long this link needs to be avoided. The awareness of the
> distribution delay statistics can potentially be used by implementations to
> dynamically determine an appropriate “hold time” for a given TE link
> (instead of using a blanket topology-wide configuration).
>
>
>
> By « delay » do you mean the IS-IS flooding time across the flooding
> domain or do you mean something else?
>

Yes, the flooding time across the area.


> If this is the flooding time, what distribution delay statistics do you
> have in mind?
>

Mean plus 2x std dev. would be a good guess at a cutoff. I reserve the
right to update this based on future experience.


> In current deployment and as a goal in order to neglect this flooding
> time?
>
> e.g., if flooding time could be reduced to 50 ms would you still need this
> timestamp?
>

We cannot guarantee that flooding time can be reduced to 50ms.  While fast
flooding is of course a good thing, reality is a harsh mistress. Other
implementations might be in the flooding path. Old software will be in the
network for a very long time. So measuring reality would be helpful.

T
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