Advertisement Interval Vs Timeout

Don/Joe/Steve/Bob,

It is nice to see some energetic discussion on the VRRP mailing list :)

I don't know if you guys have noticed but the latest version of VRRPv3
draft (08) has made a significant change related to Advertisement
Interval and Timeout.  Instead of setting the Master_Down_Interval to
the (3 * configured Advertisement Interval), it is now set to (3 *
Master's Advertisement Interval).

This change effectively makes the field Advertisement Interval in the
packet, a timeout (one third of the timeout, actually) advertised by the
Master.

This change was made to fix the exact problem that Don mentioned.  The
protocol does not need to match the Advertisement Intervals; it needs to
match the Timeout Intervals.

I think the solution in the draft is better at least in one sense.  It
is backwards compatible.  If we change the meaning of the field (from
Advertisement Interval to Timeout), the older implementations will
assume that the value in the packet is Advertisement Interval and will
set their down timer to 3 times that value.  That would cause issues!

One of the downside (and I can't see others) of the solution in the
draft is that the minimum value of the timeout allowed is 3
centiseconds.  It would be 1 centiseconds if the field was changed to be
the timeout.

Does this change address your concerns or you would like to make further
changes?  VRRPv3 is still a draft and we can still make changes to it.
At this stage of the draft, we should not be making any changes that
might not interoperate with the current version of the draft though.

Regards
Mukesh

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