Re: Service Redundancy using BFD

Ankur Dubey <> Wed, 29 November 2017 02:32 UTC

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From: Ankur Dubey <>
To: Ashesh Mishra <>, Sami Boutros <>, "" <>
CC: Reshad Rahman <>
Subject: Re: Service Redundancy using BFD
Thread-Topic: Service Redundancy using BFD
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Date: Wed, 29 Nov 2017 02:32:10 +0000
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The bitmap represents all the non-revertive services running between a pair of nodes providing redundancy. One bit per non-revertive service.

The bitmap needs to be used only if a per-service failover has to be supported (section 2.2). 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.


From: Ashesh Mishra <>;
Date: Tuesday, November 28, 2017 at 4:55 PM
To: Ankur Dubey <>;, Sami Boutros <>;, ""; <>;
Cc: Reshad Rahman <>;
Subject: Re: Service Redundancy using BFD


The bitmap that you mentioned in your previous email to demultiplex the services needs more clarity. Where is that bitmap added in the BFD frame? How does a bitmap represent a subset of the services? I feel there is an underlying assumption in the use-case that’s not clear in the proposal that simplifies the service structure.


From: Ankur Dubey <>;
Date: Tuesday, November 28, 2017 at 7:28 PM
To: Ashesh Mishra <>;, Sami Boutros <>;, ""; <>;
Cc: Reshad Rahman <>;
Subject: Re: Service Redundancy using BFD


In case you meant that C and D are network nodes (not services) peering with A-B which are providing redundancy for any L2/L3/L4-L7 services, I’d like to clarify the following:

The mechanism to indicate to C&D which node (A or B) should attract traffic for a given service is not described in this draft. Like Sami mentioned in another email, there can be many ways to do that depending on the deployment scenario.

The solution described in this draft helps to establish understanding between the network nodes proving redundancy (A and B) regarding which node should be Active for a given service.


From: Ankur Dubey <>;
Date: Tuesday, November 28, 2017 at 4:01 PM
To: Ashesh Mishra <>;, Sami Boutros <>;, ""; <>;
Cc: Reshad Rahman <>;
Subject: Re: Service Redundancy using BFD

Hi Ashesh,

Yes, multiple services can be running between A & B. The indication of Active is needed on BFD packet only when the backup node is acting as the active for a given non-revertive service.

If all non-revertive services (lets say C and D in your example) are Active on a backup node (lets say B), the new diag code is sufficient to indicate the Active status for those services.

If some non-revertive services are active on A, while others on B, the bitmap indicating active services is needed in the payload.