Ashesh, I'll take it as a given that there's an implied gripe about a lack of TLVs for BFD and a push for BFDv2. :-)
The work in here seems reasonable, but does run up against the question I always must ask: Is this actually useful/usable at high BFD rates? I understand that a likely scenario (and not documented in the draft) is you start with a sedate enough transmit interval so as to get your measurements. But once you have them, I would expect that a poll would be initiated to utilize faster timers. Once we get to the fast timers, would the procedures for handling the timestamps be reasonable to run at that rate? -- Jeff On Wed, Dec 06, 2017 at 01:52:47PM +0000, Ashesh Mishra wrote: > Hi BFD experts, > > We recently submitted a new individual contribution on BFD Performance > Measurement. Please review the document and provide comments. > > https://datatracker.ietf.org/doc/draft-am-bfd-performance/ > > This document proposes a mechanism to determine the smallest BFD transmit > interval that can be supported on the link. This is achieved by actively > measuring the one-way delay for each BFD session and setting the BFD session > intervals based on the measured delay. This allows the BFD session to adapt > to the fastest rate feasible on the current active path. > > The method described in this proposal is useful in networks where the network > latency is high, or varies with time. Trans-oceanic links and connectivity > over geo-synchronous satellites are typical examples of links where the > latency is high and the difference in latency on primary and backup paths can > be significant. Another use-case is connectivity using satellites in > mid-earth orbit (MEO) or low-earth orbit (LEO). In these systems the one-way > delay, while it is low (25msec to 150 msec), varies with time. This > variation, based on various factors, can be as high as 30 msec. With mobile > receivers, such as ships, the delay when using such connectivity can be > non-trivial to predict. This requires an automated method to determine the > optimal BFD interval to allow fastest possible recovery in case of failure. > > Thanks, > Ashesh Mishra > Mahesh Jethanandani
