Re: [2] AS400's [same] not acting similarly ??

["Tim Truax" <truax@xxxxxxxxxxxx>]

We are gonna run a test on this tonight.
I want this information from the network people.  I have inquired to see the
exact split up areas on the 2,400 byte records.
I will keep you posted.
Tim

----- Original Message -----
From: "Vern Hamberg" <vhamberg@centerfieldtechnology.com>
To: "Midrange Systems Technical Discussion" <midrange-l@midrange.com>
Sent: Friday, February 07, 2003 11:21 PM
Subject: Re: [2] AS400's [same] not acting similarly ??


> Tim, has anyone done a comm trace on the BACKUP 400, to verify the size &
> contents of the packets it is sending out?
>
> Vern (don't know what to snip)
>
> At 04:48 PM 2/7/03 -0500, you wrote:
> >Here's a stumper, (i think)
> >100 RPG program communication jobs using an antiquated but functional
LU6.2
> >connection.
> >100 jobs doing the same thing.
> >100 information extractions occurring concurrently.
> >100 jobs that run in a single sub-system on the AS400's.
> >This program referred to above receives a 45 byte REQUEST record, and
then
> >sends out a 2,400 byte RESPONSE record of information pertinent to the 45
> >byte REQUEST.
> >
> >On 1 AS400 (the main one) this works great, this AS400 pumps the results
of
> >the communication job through a LAN, possibly less that a second
turnaround.
> >It's beautiful, and everyone's happy!
> >
> >On the BACKUP AS400 (supposedly identical), this AS400 pumps the results
of
> >the communication job through a WAN that the network people say should
act
> >just like the LAN.  The length of time the actual programmatic process
takes
> >on the BACKUP AS400 is the same (about a second) but the 2,400 byte
RESPONSE
> >records are being fragmented ONLY on the BACKUP AS400 and timeouts are
> >occurring with GREAT and unacceptable frequency.
> >
> >Here's the diagnosis:
> >When we switch these 100 jobs from the main AS400 to the BACKUP AS400,
after
> >about 30 of the jobs have been switched onto the BACKUP AS400 the network
> >people determine that an unusual "round robin" thing starts to happen,
this
> >is detected ONLY ON THE BACKUP AS400.  They do not see this same thing
> >happen under any circumstances on the main AS400.  Meaning that the
BACKUP
> >AS400 system begins to segment the 2,400 byte response and put parts of
it
> >onto 1 packet, and then it moves to the next of the 100 jobs and takes a
> >part of that processes 2,400 byte record and appends it to the next
packet.
> >What is evidently happening is the 2,400 byte response is being
fragmented
> >(which should NOT be happening) and appended to a 16,000 byte packet, the
> >packets are big enough to accomodate the 2,400 byte RESPONSE that's being
> >pushed into the LU6.2 from the RPG program and one would think that it
would
> >fit within 1 of these 16,000 bytes segments.  The network people (and I
> >think they're capable) see this 2,400 byte response being broken into
> >segments and placed onto individual 16,000 byte packets and then
reassembled
> >by the receiving system.
> >They assure me the AS400's are configured identically, Both AS400's are
of
> >the same POWER level.
> >
> >I think possibly there is a setting for the operation of the MAIN AS400's
> >sub-system and the BACKUP AS400's subsystem on which these jobs run that
may
> >be askew or different.
> >
> >Any thoughts on this ??
> >
> >Tim  :-)
>
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