Hi Peggy,

 

I specified the MTU on the Gateway statement!

 

The error was DTCPRS051E - Line 24: Invalid Packet Size in Gateway
Command: 16384

Thanks.. Terry 

Terry Martin 
Lockheed Martin - CITIC 
z/OS Performance and Tuning 
(410) 786-0386 - Office 
(443) 632-4191 - Cell 
[EMAIL PROTECTED] 

  

________________________________

From: The IBM z/VM Operating System [mailto:[EMAIL PROTECTED] On
Behalf Of Peggy Williams
Sent: Friday, June 06, 2008 10:13 AM
To: [email protected]
Subject: Re: HiperSockets Setup

 

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

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"Martin, Terry R. (CMS/CTR) (CTR)" <[EMAIL PROTECTED]> 
Sent by: The IBM z/VM Operating System <[email protected]> 

06/06/2008 09:42 AM 

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Re: HiperSockets Setup

 






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: [email protected]
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

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