Re: [DNA] Review of draft-ietf-dna-link-information-03.txt

[Bernard Aboba <bernard_aboba@hotmail.com>]

>Anyway, I have a question for you Bernard: draft-iab-link-indications
>talks about the importance of damping and hysterisis -- has that
>been sufficiently addressed in the wireless parts of the
>dna-link-information document?

Damping & hystersis need to be addressed in the DNA specifications 
themselves, so that DNA can be immune to driver malfunctions.  As an 
example, RFC 4436 rate limits DNAv4 exchanges, so that a jittering driver 
would not cause a flood of DNAv4 probes.

I do think this document creates a problem by mandating that a "link down" 
event be sent on each handoff.  It is possible for a handoff to occur with 
minimal connectivity loss, so that the link was never "down", at least not 
long enough for an application to care about it.  Requiring "link down" 
events will cause harm in situations where the TCP stack or applications 
tear down connections on receipt of a "link down".   Because of the downside 
to sending a "link down" event, these events are often damped, and if a 
"link up" occurs prior to expiration of the damping timer, then a "link 
down" event may not be sent.