Hi Carlos, OK, thanks for the clarification!
Best regards, Mach From: Carlos Pignataro (cpignata) [mailto:[email protected]] Sent: Tuesday, July 18, 2017 6:26 PM To: Mach Chen Cc: Reshad Rahman (rrahman); [email protected] Subject: Re: A question about RFC5884 Hi Mach, I had not suggested it, but I think that idea has merit. If there are enough updates needed to the spec based on additional running-code learning, or ambiguities that are causing interoperable confusion, the net of a -biz can be positive. When that same idea crossed my mind, I thought that the question should be part of a larger consideration from the chairs of maturity, pipeline, and advancement of BFD specs, and not taken in isolation. 5884 seems to require localized fixes only. Thanks, Sent from my iPad On Jul 18, 2017, at 9:14 AM, Mach Chen <[email protected]<mailto:[email protected]>> wrote: Hi Carlos, Do you suggest to do a 5884-bis? Best regards, Mach From: Carlos Pignataro (cpignata) [mailto:[email protected]] Sent: Monday, July 17, 2017 10:56 PM To: Mach Chen Cc: Reshad Rahman (rrahman); Ashesh Mishra; [email protected]<mailto:[email protected]> Subject: Re: A question about RFC5884 Hi Mach, On Jul 17, 2017, at 10:42 AM, Mach Chen <[email protected]<mailto:[email protected]>> 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:[email protected]] Sent: Monday, July 17, 2017 6:58 AM To: Reshad Rahman (rrahman) Cc: Mach Chen; Ashesh Mishra; [email protected]<mailto:[email protected]> 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) <[email protected]<mailto:[email protected]>> 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" <[email protected]<mailto:[email protected]> on behalf of [email protected]<mailto:[email protected]>> wrote: Hi Ashesh, Thanks for your prompt response, we're on the same page! Best regards, Mach -----邮件原件----- 发件人: Ashesh Mishra [mailto:[email protected]] 发送时间: 2017年7月16日 22:26 收件人: Mach Chen 抄送: [email protected]<mailto:[email protected]> 主题: 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 <[email protected]<mailto:[email protected]>> 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
