Hi Mach, On Jul 17, 2017, at 10:42 AM, Mach Chen <mach.c...@huawei.com<mailto:mach.c...@huawei.com>> wrote:
Hi Carlos, Thanks for sharing your thoughts. IMHO, it may not be necessary to consider this LSP Ping based bootstrapping as normal LSP ping. Would it be considered an abnormal LSP Ping? :-) If RFC 5884 references RFC 4379, I'd expect it means an LSP Ping as specified in 4379, or those processes for LSP Ping be updated. Sent from my iPad And since both the ingress and egress LSR process the echo messages in the context of BFD session establishment, it should be no problem to process as described in RFC5884. BTW, RFC5884 does not specify which reply mode will be used :) Best regards, Mach From: Carlos Pignataro (cpignata) [mailto:cpign...@cisco.com] Sent: Monday, July 17, 2017 6:58 AM To: Reshad Rahman (rrahman) Cc: Mach Chen; Ashesh Mishra; rtg-bfd@ietf.org<mailto:rtg-bfd@ietf.org> Subject: Re: A question about RFC5884 Hi, I also agree with the conclusion of this thread in regards to what RFC 5884 says. However, can that be in conflict with RFC 8029's procedures, in which the reply might be expected? https://tools.ietf.org/html/rfc8029#section-4.4 There is certainly no need to carry any information in an MPLS LSP Ping reply, since at that point the discriminatory are already carried in BFD. The reply might be important only if FEC validation fails. I wonder though if the text of "The egress LSR MAY respond with an LSP Ping Echo" intended to convey that whether to reply or not depends on the value of the Reply Mode field in the Echo request. Sent from my iPad On Jul 16, 2017, at 6:22 PM, Reshad Rahman (rrahman) <rrah...@cisco.com<mailto:rrah...@cisco.com>> wrote: Hi, My take too is that the RFC is pretty clear that Echo reply from egress LSR is not mandatory. Regards, Reshad. On 2017-07-16, 4:29 PM, "Rtg-bfd on behalf of Mach Chen" <rtg-bfd-boun...@ietf.org<mailto:rtg-bfd-boun...@ietf.org> on behalf of mach.c...@huawei.com<mailto:mach.c...@huawei.com>> wrote: Hi Ashesh, Thanks for your prompt response, we're on the same page! Best regards, Mach -----????----- ???: Ashesh Mishra [mailto:mishra.ash...@outlook.com] ????: 2017?7?16? 22:26 ???: Mach Chen ??: rtg-bfd@ietf.org<mailto:rtg-bfd@ietf.org> ??: Re: A question about RFC5884 That's how I read it ... assuming that proper handling of the LSR echo includes gracefully dropping it on rx. Ashesh On Jul 16, 2017, at 3:58 PM, Mach Chen <mach.c...@huawei.com<mailto:mach.c...@huawei.com>> wrote: 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
