Re: [DNA] draft-ietf-dna-link-information-04.txt status

[Jari Arkko <jari.arkko@piuha.net>]

Greg,
> "
> Where it is not known that forwarding operations are available, a
> host SHOULD assume that RSTP or STP is being performed. Hosts MAY
> listen to STP/RSTP and 802.1AB messages to gain further information
> about the timing of full connectivity on the link, for example, to
> override an existing indication.
>
> Notably, though, it is not easy for a host to distinguish between
> Disabled bridge ports and non-bridge ports with no active transmitters on
> them, as Disabled ports will have no traffic on them, and incur 100%
> sender loss.
>
> If no bridge configuration messages are received within the
> Bridge_Max_Age interval (default 20s), then it is likely that there
> is no visible bridge whose port is enabled for bridging 
> (S8.4.5 of [IEEE-802.1D]), since at least two BPDU hello messages would
> have been lost.  Upon this timeout, a link up notification MUST be
> generated, if one has not been already."
>
> I believe this shows that the indications may be sent first when link-layer
> connectivity (rather than spanning-tree-connectivity) is available, but 
> that hosts need to be wary of sender loss during spanning tree calculation.
>   
This would work for me. We would essentially leave
the issue open, but describe the implications.

--Jari