Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Mon, 9 Sep 2002 17:02:13 -0600

Alan,

A frequent cause of this type of problem occurs when the
client is off subnet from the server, the client can reach
the server via the EPICS_CA_ADDR_LIST, but the client does
not see the server's beacons (because of how the server's
beacon address list is configured).

If the client does not find its PV after about 15 min then
it stops searching altogether until it see a beacon anomaly
( a significant change in a server's beacon ).

Of course the primary cause of these problems is that directed
broadcasts do not cross routers well. The solution in the future
may be to use multicasting.

Another solution is to use the CA gateway to reach off subnet
servers.

The R3.14 program casw can be used to monitor server beacon
anomalies.

Jeff

> -----Original Message-----
> From: Allan Honey [mailto:[email protected]]
> Sent: Monday, September 09, 2002 1:20 PM
> To: Jeff Hill
> Cc: Al Conrad; 'EPICS Tech-Talk'
> Subject: CA problem
>
>
> Aloha
>
> We at Keck are also having what appears to be CA problems.
>
> In our case a client may lose connection to a subset of its
> open channels. The connections never restore and the client
> must be restarted. If one starts other clients, which connect
> to the same channels, that new client has no problems whilst
> the original client continues to be disfunctional.
>
> This problem affects various systems running on different
> SUN workstations at different times. I am currently using
> a network snooping tool to try understand what is occurring.
>
> I am unsure if the problem is in CA repeater or the servers in the
> realtime systems but I suspect the repeater. Of course I am fairly
> ignorant of the CA repeater. The occurrence is very infrequent so
> it is hard to force the problem in order to study it.
>
> If anyone has any experience with this problem or tools, which
> may help, please give me a yell.
>
> Allan

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System