Experimental Physics and
Industrial Control System

[email protected] (Jeff Hill) · Wed, 8 Nov 95 17:21:38 MST

Hello All,

Recently a subtle problem related to the IOCs reconnecting to the
log server has been fixed. 

Symptoms:
o Long hang connecting to the log server in iocInit.

Cause(s):
o I followed normal convention and allowed the local port number 
	for the log client to be assigned by vxWorks
o The log client's local port number is always assigned to be the
	same number (1044) when the IOC reboots
o SUNOS4 becomes confused when the IOC begins sending TCP SYNC messages
	from a port that it has been serving before the IOC rebooted
o SUNOS4 does not send a TCP FINISH to the IOC even if the TCP/IP sequence
	numbers are obviously wrong.
o vxWorks does not send a TCP FINISH when the user types ^X

Solution:
o Transparently reconnect to the log server several times in order to
	guarantee that we dont start out on a port number that is in use 
	when the IOC reboots.

The necessary changes have been checked in at APS. I dont know if this
will end up in 3.12.2.

I have also fixed the log client so that it will reconnect to the log 
server if the log server is restarted (as suggested by LBL).

It is interesting that this problem does not appear to show up when
CA clients are rebooted (and they must reattach to CA servers running
under vxWorks). I assume that this results from a slightly different
implementation of TCP/IP under vxWorks. I will look into this in greater
detail when more urgent matters have been resolved (ie list of priorities 
arrived at at the last collaboration meeting).

Jeff

______________________________________________________________________
Jeffrey O. Hill			Internet	[email protected]
LANL MS H820			Voice		505 665 1831
Los Alamos, NM 87545 USA 	FAX		505 665 5107

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System