Re: Service Redundancy using BFD

Greg Mirsky <> Tue, 28 November 2017 16:16 UTC

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From: Greg Mirsky <>
Date: Tue, 28 Nov 2017 08:16:29 -0800
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Subject: Re: Service Redundancy using BFD
To: Ankur Dubey <>
Cc: "" <>, Reshad Rahman <>, Sami Boutros <>
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Hi Ankur,
usually this problem, as I understand it from the document, is handled by
the special protection coordination protocol as, for example, in RFC 6378
or G.8031. PSC or APS reflect roles of working and protecting paths and
communicate over the protecting path.


On Mon, Nov 27, 2017 at 6:47 PM, Ankur Dubey <>; wrote:

> Hi all,
> Please review and provide comments for the following draft:
> *Summary of draft:*
> This draft proposes a new BFD diag code via which a node running a BFD
> session with another node, can inform the other node after a BFD session
> times out, that it didn’t go down and did live through the failure.
> Such notification is useful for a set of nodes providing Active/Standby
> redundancy. When these nodes are running multiple L2/L3/L4-L7 services  in
> non-revertive mode of redundancy, the standby node taking over as active
> for non-revertive services after BFD times out needs to indicate in the BFD
> packet that it outlived the other failed old active node. The new diag code
> will be used for this purpose. When this diag code is set in the BFD
> packets, it will provide an indication to the failed old active node that
> it MUST NOT activate the non-revertive services when it comes up.
> For providing a per service level failover, a node activating certain
> non-revertive services needs to indicate that it is Active ONLY for those
> non-revertive services. This can be done by using a unique bitmap where
> each bit position is uniquely identifying a service. This unique bitmap is
> configured on all nodes by a network controller. When there is at least one
> non-revertive service for which a node is not active AND it is active for
> at least 1 non-revertive service, this node will set bits identifying the
> active services in the bitmap and send it in the payload of the BFD packet.
> Thanks,
> --Ankur