Re: BFD stability follow-up from IETF-91

[Manav Bhatia <[e-mail]>]

Hi Greg,

What if i dont have a single-hop session? Do you want the operator to set
up one between the sender and its immediate next-hop and another between
the receiver and its immediate next-hop?

Cheers, Manav

On Mon, Dec 8, 2014 at 11:52 AM, Gregory Mirsky <[e-mail]
> wrote:

>  Hi Santosh,
>
> do you envision scenario when BFD multi-hop and single-hop sessions that
> share the same sender behave differently? In my opinion, if multi-hop
> session is unstable and single-hop is stable, then the problem is likely in
> the network and thus is real, rather than in the BFD sender and more
> implementation specific. Thus running BFD Echo even without cooperation of
> the next hop node (no timestamps there) would give sender information about
> latencies BFD is subjected to in this node.
>
>
>
>                 Regards,
>
>                                 Greg
>
>
>
> *From:* Rtg-bfd [mailto:[e-mail]] *On Behalf Of *Santosh
> P K
> *Sent:* Monday, December 08, 2014 2:07 PM
> *To:* Manav Bhatia; Marc Binderberger
> *Cc:* [e-mail]
> *Subject:* RE: BFD stability follow-up from IETF-91
>
>
>
> Hello Mac and Manav,
>
>      Are we just talking about singlehop? How about MPLS BFD and multihop
> where echo does not work?
>
>
>
> Thanks
>
> Santosh P K
>
>
>
> *From:* Rtg-bfd [mailto:[e-mail]
> <[e-mail]>] *On Behalf Of *Manav Bhatia
> *Sent:* Monday, December 08, 2014 9:33 AM
> *To:* Marc Binderberger
> *Cc:* [e-mail]
> *Subject:* Re: BFD stability follow-up from IETF-91
>
>
>
> Hi Marc,
>
>
>
>
>
> * Greg's echo idea is of course do-able - when you think timestamping in
> hardware can be done then it can be done in the forwarding path for echos
> as
> well. Depends on your hardware :-) and on an agreed (minimal) format for
> echo. As mentioned BFD echo is not defined/used for multiple BFD features,
> which limits it's use though.
>
>
>
> For the echo mechanism to work, do you agree that you would have to
> continuously send Echos so that you can detect the issue?
>
>
>
> Or are you suggesting that once BFD flaps we will start sending Echoes
> overloaded with debug information to detect the issue?
>
>
>
> I'd like to understand this before the mailing list sees a barrage of
> emails. Alternatively, we can also take it offline and only report the
> summary of our discussion to the list.
>
>
>
> Cheers, Manav
>