RE: Advertisement Interval Vs Timeout

Both RFC3768 and draft-ietf-vrrp-ipv6-spec-08 state that the
Advertisement Interval, which is included in ADVERTISEMENT packets, is
used for troubleshooting misconfigured routers.  It is used to validate
received packets - packets that contain the wrong value are discarded.
The routers use their locally configured intervals to actually time out.

Are we suggesting some other behavior?

--Joe.

> -----Original Message-----
> From: Don Provan [mailto:[email protected]]
> Sent: Tuesday, April 17, 2007 5:24 PM
> To: [email protected]
> Cc: [email protected]
> Subject: RE: [VRRP] Advertisement Interval Vs Timeout
> 
> Danny,
> 
> Actually I agree with you 100%, and I made similar
> arguments earlier. Theoretically, this result doesn't
> make sense and I suspect it really means something
> else is going on that we don't yet understand.
> 
> Nevertheless, since *I* was not (and am still not)
> in a position to get any hands on experience, I felt
> I should defer to the people that were actually seeing
> the issues first hand, even when the protocol itself
> was being complicated by the issue, as was the case
> then.
> 
> Happily, as things stand now (with the Minimum
> Advert Int), it's no longer a protocol issue at all,
> and we can leave it to administrators actually in the
> field with real operational environments to adjust
> this value if they find they need to. The cost to
> the protocol itself is now essentially zero: "less
> than or equal to" vs. just "equal to", and even that's
> in the implementation, not the protocol description.
> 
> (Well, except I guess it makes sense to add an
> "actual advert interval" to the MIB, although I
> hate to say it.)
> 
> -don
> 
> > -----Original Message-----
> > From: Danny J. Mitzel [mailto:[email protected]]
> > Sent: Tuesday, April 17, 2007 2:00 PM
> > To: [email protected]
> > Subject: RE: [VRRP] Advertisement Interval Vs Timeout
> >
> >
> > I'll admit right up front that I haven't been
> > following the subsecond timers draft, feel free to
> > ignore this question if it's already been discussed.
> >
> >
> > --- Don Provan <[email protected]> wrote:
> > > If the master were allowed to send at faster rates,
> > > more than three advertisements could be sent per
> > > timeout interval, which is what people experimenting
> > > with faster timeouts tell us they found was
> > > necessary for stability in that environment.
> >
> > I'm not understanding why people experimenting with
> > faster timeouts are claiming more Advertisements
> > are required to insure VRRP stability?  Stability of
> > the protocol as currently written is not dependent on
> > the timeout interval it's dependent on the packet loss
> > rate (link Bit Error Rate (BER) and/or switch or
> > router packet drops).  Are the fast timeout
> > experimenters emulating higher BER or non-linerate
> > capable switches with high packet drop rates?
> >
> > I agree that the ability to send Advertisements at a
> > higher rate can make VRRP more robust in LANs with
> > extremely high BER or congested switches.  I'm just
> > trying to understand if there's some claim that this
> > is required just because the timeout is scaled down?
> >
> >
> > danny
> >
> >
> >
> >
> > _______________________________________________
> > vrrp mailing list
> > [email protected]
> > https://www1.ietf.org/mailman/listinfo/vrrp

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