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
