remote client not updating redlights
John Shott
shott at stanford.edu
Sat Jun 28 12:29:44 PDT 2008
Peter:
Hmmm. that's interesting and I haven't heard of others experiencing this
problem ... but let me explain exactly what is supposed to be happening ...
In coral, clients are updated everytime someone enables or disables a
tool, makes or deletes a reservation, reports (or clears) a problem or
shutdown by messages that we call "events". For the in-lab Coral
clients (that is the clients that are automatically started when you are
in the lab) each clients is registered to receive events and is notified
any time any of these things happen. Remote Coral, however, behaves a
little bit differently ...because many Remote Clients are likely behind
some sort of a firewall, if we sent them unsolicited events, they would
likely get blocked by the firewall. So each remote client sends in a
message once every 5 minutes that says, in effect, "Send me any events
that have been posted within the last few minutes ..." While that means
a remote client could be as much as 5 minutes out of date, in general
that isn't a problem. And, if you make a reservation on a remote
client, you should see it immediately because the client "self-posts"
it's own event.
I've just done some testing of my own remote client ... coupled with
clearing a test shutdown from an in-lab client and confirmed that after
a couple of minutes, by remote client showed the shutdown was cleared.
Now, we have seen that there are "heavily locked" down firewalls that
won't allow a Remote Client to run at all .... for example at the NASA
Ames Research Center .... but we haven't seen a firewall that will
mostly run but would block requests for events, so I'm a bit confused as
to what may be happening in your case. I have no idea where
128.12.142.202 is, but it would be interesting to see if this behavior
occurs when you have remote coral connected from other locations .... or
whether you are seeing something that we haven't seen before that may be
local to that site.
Thanks,
John
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