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<== Date ==> <== Thread ==>

Subject: Multiple C++ based CA servers on the same host and port number
From: johill@lanl.gov (Jeff Hill)
To: "EPICS-tech-talk (E-mail)" <tech-talk@aps.anl.gov>
Date: Thu, 28 Jan 1999 14:44:40 -0700
All,

A known problem exists with the C++ based server library (which is not 
used in the IOCs but is used with newly developed server side tools).

If you run more than one CA server tool on the same host with the same
server UDP port number then the CA clients will see beacons from both 
of these servers as one server, and they will falsely conclude that the 
server beacon period is changing erratically. This will lead client's with 
disconnected PVs to continuously conclude that there is a newly available 
server on the network, and therefore broadcast at a benign but faster rate 
than is normal. These clients will not back off to a slower broadcast rate 
as the they see that they are not responded to because they will continuously 
conclude that a new server is on the network.

Because of the above problem I don't recommend that sites run more 
than one server on the same UDP port number on the same host
(probably a rare configuration in the past due to IP kernel limitations)
until a solution to this problem is installed.

Jeff
______________________________________________________
Jeffrey O. Hill                      Internet     johill@lanl.gov
LANL MS H820                    Voice         505 665 1831
Los Alamos NM 87545 USA   FAX          505 665 5107


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