Experimental Physics and
Industrial Control System

"Jeff Hill" <[email protected]> · Fri, 24 Sep 2010 06:33:41 -0600

> We are wondering here, how to host multiple soft 
> IOCs on the same computer, possibly
> sharing the same UDP CA request port.

It is a simple matter to add multicast support to the 
ca server, and that will address this issue.

Jeff
______________________________________________________
Jeffrey O. Hill           Email        [email protected]
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Message content: TSPA

> -----Original Message-----
> From: [email protected] [mailto:tech-talk-
> [email protected]] On Behalf Of Anze Zagar
> Sent: Friday, September 24, 2010 5:02 AM
> To: [email protected]
> Cc: [email protected]
> Subject: RE: Soft IOCs and Port Numbers
> 
> Hi Matthew,
> 
> Actually the issue is not on client side. CArepeater is used for client
> applications to share the beacon UDP port (e.g. EDM screens and also
> IOCs because they can be clients to one another...). We are wondering
> here, how to host multiple soft IOCs on the same computer, possibly
> sharing the same UDP CA request port. For broadcast UDP packets this is
> not really an issue, because Linux UDP stack is implemented in such a
> way that it by default fans out the packet to all services running on
> that particular port. Though, I'm not convinced that this is really
> standard UDP stack behavior and that we have any guaranties it will
> still work with future versions of Linux kernel. The second problem is
> that at some stage ITER may also want to configure some client to send
> unicast requests. Then it will for certain not work on Linux because in
> that case only one IOC will in fact receive the request.
> 
> I see a few possibilities here:
> o) Ignore the problem and assume that in ITER broadcast UDP will always
> be used and there will be no problems in future. This is also ok if we
> assume that at some stage they will switch to EPICS v4 where port
> sharing will no longer be an issue.
> o) Do something with modular epics and have only one IOC application
> running, hosting all the required IOCs as modules.
> o) Assign different ports to different IOCs. This will very likely
> course cause a lot of other manageability issues.
> 
> Cheers,
> Anze Zagar.
> 
> 
> 
> On Fri, 2010-09-24 at 11:22 +0100, [email protected] wrote:
> > Here at ITER, t
> > Hi Pam,
> >
> > We use the CArepeater UDP server on our linux hosts.
> >
> > http://www.slac.stanford.edu/comp/unix/package/rtems/epics-
> 3.14.6/base/html/CAref.html#Repeater
> >
> > Is that what you need?
> >
> > Cheers,
> > Matthew
> >
> >
> >
> ______________________________________________________________
> >         From: [email protected]
> >         [mailto:[email protected]] On Behalf Of Pam Gurd
> >         Sent: 24 September 2010 09:18
> >         To: EPICS tech-talk
> >         Subject: Soft IOCs and Port Numbers
> >
> >
> >
> >         hey're asking me about how to manage the problem of ensuring
> >         that each of the soft IOCs running on a host has a distinct
> >         port number.
> >
> >
> >
> >         What have people done to solve this problem?
> >
> >
> >
> >         Thanks.
> >
> >
> >
> >            Pam.
> >
> >
> >
> >
> >
> >
> >
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System