Experimental Physics and
Industrial Control System

Randall Cayford via Tech-talk <tech-talk at aps.anl.gov> · Wed, 17 Jun 2020 12:10:10 -0700

I’m trying to understand what the options are for working with EPICS across subnets and for remote access.

We have some IOCs running on subnet A.  We also need access to a few PVs from IOCs running on network B.  I would like to access PVs on both A and B from subnet C.  Subnets are separated by multiple layers of routers.  Subnet A is on the experimental floor and is pretty locked down to control network traffic. 

My understanding is that EPICS_CA_ADDR_LIST will let me access other subnets but only if if multicast packets are passed between the subnets or if there is a cagateway running.  Is that correct? 

If cagateway is running on subnet B does it pass only the packets requested by a client on subnet A or does it pass all the broadcast traffic from subnet B?

Is EPICS_CA_ADDR_LIST supposed to include all of subnet B (subnetB.255) or just the IP of the gateway?

What router access rules are needed to allow connections to PVs on B from clients on A or C?

Does PVaccess change any of this?

I’m sure this is all somewhere in the documentation but I haven’t been able to sort it out by reading.  This involves a lot of different people to set up so I’m looking for some clarity on what needs to be done and who needs to do it.

Randall

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System