A question about RFC5884

Mach Chen <mach.chen@huawei.com> Sun, 16 July 2017 13:58 UTC

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From: Mach Chen <mach.chen@huawei.com>
To: "rtg-bfd@ietf.org" <rtg-bfd@ietf.org>
Subject: A question about RFC5884
Thread-Topic: A question about RFC5884
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Date: Sun, 16 Jul 2017 13:58:15 +0000
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Hi BFDers,

We met a multi-vendor interoperate issue recently, it's about whether an Echo reply is necessary.

In Section 6 of RFC5884, 2nd paragraph

"... The egress LSR MAY respond with an LSP Ping Echo
   reply message that carries the local discriminator assigned by it for
   the BFD session."

>From the above text, my understanding is that an Echo reply is optional, the egress LSR can freely to return or not return an Echo reply, and the Ingress LSR should not expect there MUST be an Echo reply, but if there is one, it should handle it properly.

Is my understanding correct? 

Thanks,
Mach