[ntp:questions] Re: status of multicast
David L. Mills
mills at udel.edu
Mon Nov 29 02:21:53 UTC 2004
I imagine you are using symmetric key cryptography, so you only need to
authenticate once. In public key cryptography the keys are refreshed
once per day as the server rolls a new cookie. The client certainly does
use a unicast path, as that's how it can determine the broadcast delay,
in your case probably 270 ms. I don't know why it volleys with the
server on every broadcast received. It was not designed to do that and
doesn't do that here. The volley packet interval is two seconds. I trust
your unicast roundtrip delay is less than that. I'd tell you to light up
the lastest tarball, but the latest tarball has defective IPv4 multicast.
Dale Schultz wrote:
> I was one of those people that made several inquires about multicast
> mode. My application is in a hybrid satellite network, where the
> multicast packets are sent over the satellite link and received through
> a DVB card (sat0) in the remote server. When the remote server
> authenticates it does so with the unicast address of the server over a
> point-to-point (eth0) terrestrial link. The odd behavior I typically
> see is that ALL the remote servers will attempt to authenticate at every
> multicast interval. This does not scale well with 8000 remote servers.
> What I'd love to see is an initial authentication exchange and then the
> remote servers shut up and listen to the multicast signal and never
> authenticate again unless they've restarted or the signal has been lost
> for an extended period of time.
> I'd be more than will to test any new code in this environment if it can
> be made to work efficiently, no authentication storms.
> Thanks. Dale
> Harlan Stenn wrote:
>> Compiling is not the issue.
>> It's running it that counts, and then if there is a problem the most
>> help would be to be able to debug the problem and then even propose a
>> In article <co8hru$8sl$1 at reader2.nmix.net>,
>> james edwards <jamesh at cybermesa.com> wrote:
>>>> It would be great if anybody else who was familiar with multicast
>>>> was able
>>>> to pitch in.
>>> If it would be of help I can compile ntpd from the dev tarball and
>>> test it
>>> on my networks.
>>> Let me know or otherwise i will wait from the production tarball to come
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