Re: ATM/Token Ring Network (TCP/IP)

["Jim Franz" <franz400@xxxxxxxxxxxx>]

Just to add to the discussion, many times I have seen the
routers configured for spoofing. What this seems to do
is the router at the as400 site will block the "polling" transactions
the 400 sends to remote controllers, devices to determine if they
are still active. The remote site never receives the poll. But the
local router will spoof or fake a response that all is well. Network
techs will do this to reduce traffic. Turn it off! Spoofing blocks
any polling signals, not just as400.
jim franz

----- Original Message -----
From: "Philipp Rusch" <Philipp.Rusch@rusch-edv.de>
To: <midrange-l@midrange.com>
Sent: Tuesday, March 12, 2002 3:50 AM
Subject: Re: ATM/Token Ring Network (TCP/IP)


> Hello Dwayne,
>
> exactly my point of view !
> I  ALWAYS had a struggle with network providers when loosing
> connections on 5250 sessions, they ALWAYS tell you its your
> sort fo "timeout" settings that must be wrong and it ALWAYS
> came out that there either was a bad config in their routers OR
> a faulty line.
> A little story on this (I have others of this sort):
> We were migrating a private network in germany with seven
> locations connected to a main site through frame relay from one
> provider to another and using a different carrier.
> Some locations went smooth, but in Hamburg for example, it
> was a mess ! Since 13th of december 2001 (!) we told them, we
> are having problems when sessions drop during working hours
> (main site in different location, one central AS/400).
> Until last week (!) they sent technicians from the carrier, the
> network provider sent his people, they made me change settings
> on the AS/400, we checked everything on our side ...
> They "improved" their router configs nearly every day ..
> Finally it was a "synchronisation" problem on the (physical) line
> as they told us, they exchanged the modem on that site and
> made a change in configs to put in "filler frames" to keep up
> synchronised.
>
> Since then we are up and running with no further problems
> at all !
>
> The problem with this error was, that nobody ever saw a
> definitive error logged anywhere, so everybody involved
> said "with our equipment everything is 100% okay" but still
> we were loosing contact several times a day.
> They found out using a lanalyzer for several days, then.
>
> I know that ATM sometimes has similar problems, but I'm
> not very familiar with it, maybe it's worth a shot.
>
> HTH, Philipp Rusch
>
> Dwayne Lindner schrieb:
>
> > >
> > > This is a multipart message in MIME format.
> > > --
> > > [ Picked text/plain from multipart/alternative ]
> > > AS/400 620 with a 2816 ATM network card going to an IBM 8274
> > > hub, going from one IBM 8270 to a remote IBM8270. It's the
> > > PC's on the remote 8270 which are freezing. No major network
> > > traffic, and none AS/400 traffic is carrying on as normal,
> > > it's just the 5250 sessions which are freezing. A WRKACTJOB
> > > shows them as status RUN but taking no CPU cycles.
> > >
> >
> > Using TCP/IP I take it ??
> >
> > Get your network boffins to check, double check, and triple check the
router
> > configs.
> >
> > I've had a few similar situations and in every instance it's been a
stuffed
> > router or other network config.
> >
> > You can fool around with your tcp configuration and stuff, but I doubt
it's
> > the problem unless your timeout values have been changed from the
defaults.
> >
> > Dwayne Lindner
> > Team Leader - Data Centre
> > Wesfarmers Rural Information Technology
> > 184 Railway Parade, Bassendean WA 6054
> > Ph: (08) 9273 5365    Mob: 0407 386 693
> > Email: dwayne.lindner@writ.wesfarmers.com.au
> > _______________________________________________
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