Experimental Physics and
Industrial Control System

Perhaps I should be more clear.  When I was at the SNS, we had multiple soft IOCs running on each of several servers.  We used the EPICS_CA_SERVER_PORT environment variable to give each one a unique port; however, this solution was, and continues to be, up to the goodwill and good management of the IOC engineer.  (I have a private message from Kay, but I should get his permission before I share it.)  I was wondering whether anyone had a more structured approach.

 

 

   Pam.


----- Original Message -----
From: Anze Zagar <[email protected]>
Date: Friday, September 24, 2010 3:00 pm
Subject: [Fwd: RE: Soft IOCs and Port Numbers]
To: Pam Gurd <[email protected]>

> Hi Pam,
>
> This answer was not sent to EPICS Tech Talk but rather to me directly,
> so I'm forwarding it FYI.
>
> Cheers,
> Anze.
>
>
> -------- Forwarded Message --------
> From: Touchard Dominique <[email protected]>
> To: Anze Zagar <[email protected]>
> Subject: RE: Soft IOCs and Port Numbers
> Date: Fri, 24 Sep 2010 13:45:02 +0200
>
> o) Do something with modular epics and have only one IOC application
> running, hosting all the required IOCs as modules.
>
> Hi Anze,
>
> As far as I'm concerned, for the SPIRAL2 control command
> project, we has organized our software implementation with EPICS
> modules. An application is an IOC. An equipment interface is a
> module. An IOC application controls a facility line section or
> function.
> I should say that I'm a little bit curious. On the other way,
> why do you need few IOCs on the same host? Is it really a need,
> a constraint caused by a lack of implementation method or by an
> unmanaged(able) integration process?
>
> Dominique Touchard.
>
> -----Message d'origine-----
> De : [email protected] [mailto:tech-talk-
> [email protected]] De la part de Anze Zagar
> Envoyé : vendredi 24 septembre 2010 13:02
> À : [email protected]
> Cc : [email protected]
> Objet : RE: Soft IOCs and Port Numbers
>
> Hi Matthew,
>
> Actually the issue is not on client side. CArepeater is used for
> clientapplications 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
> alwaysbe 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:tech-
> [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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