Experimental Physics and
Industrial Control System

"Kasemir, Kay" <[email protected]> · Wed, 16 Oct 2013 10:19:08 -0400

This is caused by a shortcoming in most network kernels:
Both IOC-01 and IOC-02 listen to the CA name searches, but only the one started _last_ gets them, because they are sent to EPICS_CA_ADDR_LIST="serv01", where I assume serv01 is the IP address of your headless server.

For both IOC-01 and IOC-02 to see the CA name searches, you must use broadcasts.
So you must set 
export EPICS_CA_ADDR_LIST="broadcast-address-of-serv01"

Run /sbin/ifconfig on serv01 to get its broadcast address.

And yes, routers between your client computer and serv01 must be configured to allow such broadcasts.

In the end, you may have to use a CA gateway, where again the CA gateway on the subnet where serv01 resides it configured to use EPICS_CA_ADDR_LIST="broadcast-address-of-serv01", but your CA client then uses EPICS_CA_ADDR_LIST="ip-address-of-the-gateway".
-> Network routers are happy because ip-address-of-the-gateway is a plain IP address
-> IOCs get the name searches because gateway uses broadcast-address-of-serv01, so multiple IOCs on serv01 will see them.

Thanks,
Kay

On Oct 16, 2013, at 10:01 AM, Alan Greer <[email protected]> wrote:

> Hi all,
> 
> I'm suffering from a problem with a unique setup that I have not used previously.
> 
> I have a headless server (serv01) running two soft IOCs (IOC-01 and IOC-02).
> I have another machine on a separate subnet that runs the EDM GUI applications for those IOCs.
> caRepeater is running on serv01.
> On the GUI machine I setup the following
> export EPICS_CA_ADDR_LIST="serv01"
> export EPICS_CA_AUTO_ADDR_LIST=NO
> 
> 
> If I only run IOC-01 and run the GUI it connects to the IOC-01 records fine.
> If I only run IOC-02 and run the GUI it connects to the IOC-02 records fine.
> 
> If I run IOC-01 and then IOC-02 and then run the GUI it only connects to the IOC-02 records.
> If I then stop IOC-02 the GUI can then connect to IOC-01 records.
> 
> If I run the GUI first, then start IOC-01 it connects to IOC-01 records.  If I then run up IOC-02 it connects to IOC-02 records also.  However, opening any additional screens can then no longer connect to IOC-01 records.
> 
> I should just make it clear that the records on IOC-01 and IOC-02 all have different names, there is not a name problem.
> 
> I hope I have explained this with enough detail, can anyone help me so that the connections to IOC-01 are not lost(?) when running up IOC-02.
> 
> Kind regards, Alan Greer
> 

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System