Is PCAS able to connect to PVs without UDP broadcast

[mirek23]

Hello,

I am using ca gateway which depends on PCAS. It looks like that there is no way to use the server part of the gateway to connect to PVs
using just TCP connection and EPICS_CA_NAME_SERVERS variable configuration unless there is such an functionality in PCAS which I do not how to tweak? Please give me some guidance on that.
Thank you

Best Regards
Mirek

[anjohnson]

Hi Mirek, I'm not sure that I understand your configuration from your descriptions so far. I'm wondering if the terminology you're using is mixed up.

I can use a standard CA client to connect to a CA Gateway by just setting the EPICS_CA_NAME_SERVERS variable like this:

Kato$ caget sioc2odm1:heartbeat
Channel connect timed out: 'sioc2odm1:heartbeat' not found.
Kato$ EPICS_CA_NAME_SERVERS=cagate1 caget sioc2odm1:heartbeat
sioc2odm1:heartbeat            2.07694e+06

The gateway lives in a different subnet to my workstation, and I can access it either by setting EPICS_CA_ADDR_LIST or EPICS_CA_NAME_SERVERS. Using the latter as above the caget program should only be using a single TCP socket to connect to the PCAS for both its name search and the data transfer. The PCAS implements the server side of the gateway, i.e. it is a server so it looks like an IOC.

It may be that you're trying to use a different configuration. The side of the gateway that talks to the control system IOCs is known as the client side, and uses the CA client library from Base to find and connect to those IOCs. As such it can be configured to use one or more name-servers that live inside the protected subnet by setting EPICS_CA_NAME_SERVERS when running the gateway.

If you don't want the client side of the gateway to use broadcasts to find the PVs inside the machine network you would need to run a name-server there, or I supposed you could set EPICS_CA_NAME_SERVERS to the IP addresses of all of the IOCs, but that would be hard to do and wouldn't scale.

I think we need more information about what you're trying to do in order to help you further. Please given an explicit description of your configuration.