Re: error of beacon

[Ralph Lange <ralph.lange@gmx.de>]

On 05/08/2014 20:33, Hu, Yong wrote:

Hi Azra,

I guess there are multiple Ethernet ports on the computer where the PLC ioc is running. Put the two lines below at the front of your ioc startup script (just after the line #!), then change “ioc-subnet-broadcast-ip …” based on your networking settings,  and the annoying CA beacon message should be gone.

epicsEnvSet("EPICS_CA_AUTO_ADDR_LIST", "NO")

epicsEnvSet("EPICS_CA_ADDR_LIST", “ioc-subnet-broadcast-ip such as 10.0.153.255”)

You need to find out the broadcast IP of your ioc (Channel Access) subnet: the command ifconfig on Linux should tell you what you should use.

I have been using this quick fix a lot and it works very well. Hope it work for you.

Yong

NSLS-II Controls Group

Let me add ~3cts of explanation...

Roughly speaking, Channel Access uses three mechanisms on the network (default methods and ports in parentheses):
- Beacons, aka alive message broadcasts, sent from the server (UDP, 5065)
- Name resolution traffic, two-way (UDP, 5064) (recently added: TCP, 5064)
- Data and control traffic, two-way (TCP, 5064)

The error message is obviously from the beacon sender thread, failing to send to a specific address on port 5065.

If no environment variables are set, beacons are sent to the broadcast addresses of all configured network interfaces (except loopback), which "just works" in most cases.

The fact that the beacon thread tries to send to a specific address looks as if EPICS_CA_ADDR_LIST has been set to a specific address, and no beacon receiver thread (caRepeater) is running on that machine, or it sends back the mentioned ICMP packages for some other reason.

If this variable setting is a needed and verified (and not a mistake), you should probably set the beacon broadcast mode and the beacon address list separately and explicitly by setting
EPICS_CAS_AUTO_BEACON_ADDR_LIST to YES or NO (depending on if you want beacons sent to all configured networks) and EPICS_CAS_BEACON_ADDR_LIST to any specific list of addresses you want the IOC to send beacons to.

This will have the same effect on the beacons as the setting that Yong uses, but does not affect the name resolution of the Channel Access client on that IOC.

Last not least: Of course all this, and much more, is described in the Channel Access Reference Manual [1].

Cheers,
~Ralph

[1] http://www.aps.anl.gov/epics/base/R3-14/12-docs/CAref.html

From: Azra Jabeen <azrajabeen3@gmail.com>
Date: Tuesday, August 5, 2014 at 5:52 AM
To: "tech-talk@aps.anl.gov" <tech-talk@aps.anl.gov>
Subject: error of beacon

Can some body help me to sort put the error
../online_notify.c: CA beacon (send to "192.168.1.143:5065") error was "Connection refused"
s7plcReceiveThread Client1: recv(8, ..., 7, 0) failed: Success

While running ioc . My ioc receive 7 bytes data and I can see it but this message is continuously displaying

How I can get rid of this

Thanks
Azra