Experimental Physics and
Industrial Control System

Rok Sabjan <[email protected]> · Thu, 24 Aug 2006 10:52:28 +0200

Chris,

However, in the ISAC Controls system at TRIUMF we use non-standard ports
for the main ISAC Control system. Beyond that we also use different ports
from our main, non-standard ports for some of the secondary systems (yes, it

can get confusing).

We could implement the Ethereal decoder in such a way that the user
would set a list of port numbers for the CA protocol in case non-default
ports are in use.
Since different port numbers typically designate different systems, it
might also make sense to give human-readable names to these ports, and
show this text as a special field, which could then also be used for
filtering, searching and in packet info display.
The reasons for these non-standard ports aside, I have a question about how
the CA packets will be recognized. Will it be purely based on
source/destination port, or some other header in the packet? If it will be
based solely on ports, do you foresee the ability to customize the ports
associated with the CA protocol in the proposed CA ethereal plug-in?

CA packets can not be reliably identified by other means than by port
numbers (e.g., they don't contain magic codes or anything of the sort).
As said above, the port numbers would thus be customizable to cover your
case.
As a side note, do other labs use non-standard CA ports, or are we on our own
here?

At Cosylab we also use non-default ports to ensure isolation of systems.
Cheers,
Rok

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System