Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Thu, 8 Mar 2007 10:28:37 -0700

> On my MAC (OSX 10.4.8), EPICS base-3.14.9, medm 3.11:
> 
> When I set EPICS_CA_AUTO_ADDR_LIST to NO and have the EPICS_CA_ADDR_LIST
> pointing to the list of IOCs medm does not find all PVs. Sometimes the
> connections work for a short time then several IOCs are not seen anymore.
> If I set it to YES, medm finds them always.
> 
> In the xterm window I get some error messages from really not existing
> IOCs:
> CAC: error = "Host is down" sending UDP msg to 140.181.98.50:5064
> But the lost ones are not reported!
> 
> I use the same list of IOCs on other linux boxes and have no problem
there.
>

What is the response to "ping -s 140.181.98.50"?

PS: Behavior is known to vary between IP kernels for such unicast addresses
if there are two or more daemons (in this case two or more CA UDP servers)
listening to the same {IP address, port} tuple on the same host. The typical
behavior difference is that on certain IP kernels only one daemeon listening
on UDP port 5064 will receive a UDP message with a unicast destination
address, but in contrast on other IP kernels all daemeons listening on UDP
port 5064 will receive such messages. In my experience UDP frames with
broadcast address destinations always go to all registered listeners
listening on UDP port 5064 - a uniform behavior across IP kernel
implementations.

PPS: One possible workaround to the above dilemma is to use directed
broadcast addresses (router forwarded broadcast addresses) in the
EPICS_CA_ADDR_LIST. This sometimes requires enabling of "broadcast
forwarding" features in your routers. We might also add support for
multicasting to future versions of CA.

Jeff

> -----Original Message-----
> From: Burkhard Kolb [mailto:[email protected]]
> Sent: Thursday, March 08, 2007 9:28 AM
> To: '[email protected]'
> Subject: Darwin and EPICS_CA_AUTO_ADDR_LIST issue
> 
> On my MAC (OSX 10.4.8), EPICS base-3.14.9, medm 3.11:
> 
> When I set EPICS_CA_AUTO_ADDR_LIST to NO and have the EPICS_CA_ADDR_LIST
> pointing to the list of IOCs medm does not find all PVs. Sometimes the
> connections work for a short time then several IOCs are not seen anymore.
> If I set it to YES, medm finds them always.
> 
> In the xterm window I get some error messages from really not existing
> IOCs:
> CAC: error = "Host is down" sending UDP msg to 140.181.98.50:5064
> But the lost ones are not reported!
> 
> I use the same list of IOCs on other linux boxes and have no problem
there.
> 
> Any idea?
> --
> -------------------------------------------------------------------
> Dr. Burkhard Kolb
> GSI mbH  |   KP1   |  Planckstr. 1  |  D-64291 Darmstadt
> Email: [email protected]                |  Tel.: +49 (0)6159 / 71 2667
> -------------------------------------------------------------------

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System