Experimental Physics and
Industrial Control System

Rok Sabjan <[email protected]> · Tue, 22 Aug 2006 17:34:39 +0200

Hi Ned, Matthieu et al.,
thanks for the interest. I asked our expert what would be the benefits
and here is his answer:
In addition to only filtering CA traffic, the plug-in for Ethereal would
also be able to 'dissect' the CA packet, that is, give meaning to the
plain hex-codes. Thus, every CA packet would have fields revealing
CA-specific information, such as:
 * what CA command is in a packet (CA_PROTO_SEARCH,
CA_PROTO_READ_NOTIFY, ...)

* what are the parameters of the command (channel name being sought
for, channel name that was resolved, the value of the field that was
returned, ...)

* ...
Then, filtering and searching operations could also be made relative to
those fields. Example filter:
 "find all packets that concern record ABCD"
I hope this is interesting enough. If you need additional information,
please let me know.
Best regards,
Rok

Matthieu Bec wrote:

Hi Ned,
Could we get a bit more description, maybe a draft from Cosylab what the
plugin could possibly do? It sounds very interesting.
Regards,
Matthieu
Ernest L. Williams Jr. wrote:

On Fri, 2006-08-18 at 14:59 -0400, Matt Bickley wrote:

Ned Arnold wrote:

All -
COSYLAB is interested in adding Channel Access support to Ethereal
(an open source protocol sniffer) ... for a small fee of course.
I'd like some feedback on whether this seems useful ... and how much
your institution would be willing to pitch in.
It would be one way to feel a little more independent and confident
in one's ability to investigate site-specific communication
anomalies, so it has a real payback for your project.
Send comments <and checks> to tech-talk.

We already use ethereal, and it has been very helpful for us
in diagnosing network issues and in making us aware of poorly
behaving clients.  You have to wade through a lot of
extraneous traffic to find the CA-relevant, however.  If
ethereal had CA support, the tool would be easier to use by
anyone, not just network protocol experts.

What we have done is to create some nice filters using ethereal to pick
out the EPICS CA TCP and UDP traffic.

Thanks,
Ernest

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System