Terry,
What statement did you specify the MTU on - Gateway or Link?
And what was the error you got?
Peggy Williams
z/VM - TCP/IP Development
"Martin, Terry R.
(CMS/CTR) (CTR)"
<[EMAIL PROTECTED] To
.hhs.gov> IBMVM@LISTSERV.UARK.EDU
Sent by: The IBM cc
z/VM Operating
System Subject
<[EMAIL PROTECTED] Re: HiperSockets Setup
ARK.EDU>
06/06/2008 09:42
AM
Please respond to
The IBM z/VM
Operating System
<[EMAIL PROTECTED]
ARK.EDU>
Yes, Thanks Alan. In the TCPIP PROFILE I did specify 16K but I received
an error so I changed it to 1500 which I new would get around the error.
When I did the NETSTAT displays I saw a MFS of 4096 and MTU of 32768. So
I guess the question is why did I get the error in the TCPIP PROFILE
specifying 16K? Am I missing something?
Thanks.. Terry
Terry Martin
Lockheed Martin - CITIC
z/OS Performance and Tuning
(410) 786-0386 - Office
(443) 632-4191 - Cell
[EMAIL PROTECTED]
-----Original Message-----
From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of Alan Altmark
Sent: Friday, June 06, 2008 12:13 AM
To: IBMVM@LISTSERV.UARK.EDU
Subject: Re: HiperSockets Setup
On Thursday, 06/05/2008 at 05:14 EDT, "Martin, Terry R. (CMS/CTR) (CTR)"
<[EMAIL PROTECTED]> wrote:
> Basically once I got the filename correct and added the PASSWORD for
the
> TCPMAINT 198 disk I was able to get the OBEYFILE command to work. I
did
receive
> an error on my first good try. It was balking about the MTU size being
invalid.
> I was using 16384. I changed it to 1500 and tried the OBEYFILE command
again
> and it worked.
>
> I noticed on the NETSTAT displays that the MTU actually was 32768 with
a
Frame
> Size of 4096. I used a HIPERSOCKETS device that was GENed with
CHPARM=40. So
> basically it did not use the MTU size that I had defined in the
PROFILE
TCPIP.
CHPARM=40 is a MFS of 24K, not 4096. The MTU = MFS - 8K, so the MTU is
16K. (Doc'd in the IOCP book.)
Be sure everyone using the same HiperSocket chpid has the same MTU. If
you don't, a PING will work, but a large data transfer won't.
Alan Altmark
z/VM Development
IBM Endicott
