Experimental Physics and
Industrial Control System

Dale,

yes, the routers could act differently depending on how they are/were
programmed. We don't use "routeAdd" as long as we stay on the same
subnet. I just looked up an old startup file where the ioc (temporarily,
we were still testing then) was on a different subnet than the devices
it was connected to, and in that case we used a routeAdd that had the
router's address and the subnet specified.
My understanding is that a routeAdd "0" , "x.x.x.x" tells the router
that all traffic is going "out" (and the programming of the router
decides whether "out" really means "out" or not).

Maren Purves

Dale L. Brewe wrote:
>
> Chip
> Well, something along these lines seems plausible, I guess, altho the
> gateway has not changed, nor have the ioc parameters. However, these
> problems surfaced a few days after a new main switch/router was installed.
> Clearly the problem seems to be at a pretty basic level, as I have troubles
> pinging the ioc with no CA clients running. I haven't found anything that
> looks bad in either hardware or software. In the  ioc startup, I have
> routeAdd "0", "x.x.x.x"  for our subnet gateway. Is this correct? It worked
> before, but could the routers be acting differently for some reason?
> Dale
> At 08:08 AM 8/25/99 , Chip Watson wrote:
> >Dale,
> >
> >Your problem is similar to one I tracked down at PSI. If you
> >have a gateway (default routing node) improperly set in the
> >boot parameters of the IOC, then the following scenario can
> >happen:
> >
> >(1) the first client connects, but the ioc sends all traffic for
> >that client through the gateway
> >
> >(2) the gateway eventually sends a message to the ioc telling it
> >what the correct ethernet address for that host is (it doesn't want
> >to carry traffic unnecessarily)
> >
> >(3) the ioc mistakenly updates the gateway address instead of
> >installing an explicit host entry
> >
> >(4) the second client connects, and the ioc attempts to route
> >all traffic through the gateway again, but now it uses the
> >"updated" address for the gateway, which is client one
> >
> >(5) client one refuses to forward the packets (lazy, huh?), so
> >the ioc appears to drop off the net for everyone except the
> >first client to have connected
> >
> >Log into the ioc via the console if you can, and you can watch
> >this scenario play out.  Then, check your boot parameters and
> >either fix or remove the gateway entry.
> >
> >Chip

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 Dale L. Brewe     PNC-CAT/U. of Washington
 ph: 630 252 0582         fax: 630 252 0580
 Mail:
 Argonne National Laboratory/APS
 Bldg 435E sector 20
 9700 S. Cass Ave.
 Argonne, IL 60439
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

References:

network problem w/ ioc Dale L. Brewe

Re: network problem w/ ioc Dale L. Brewe

Re: network problem w/ ioc Maren Purves

Navigate by Date:

Prev: Re: bug in EPICS R3.13 and R3.12 Kenneth Kang

Next: RE: network problem w/ ioc Jeff Hill

Index: 1994  1995  1996  1997  1998  <1999>  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024 

Navigate by Thread:

Prev: Re: network problem w/ ioc Maren Purves

Next: RE: network problem w/ ioc Jeff Hill

Index: 1994  1995  1996  1997  1998  <1999>  2000  2001  2002  2003  2004  2005  2006  2007  2008  2009  2010  2011  2012  2013  2014  2015  2016  2017  2018  2019  2020  2021  2022  2023  2024