Hi, I just read some info about jumbo frames on a swedish it magazine site. You need to have all equipment in the same net-segment support jumboframes. As soon as it goes via a router (gateway) it will be re-packed to whatever the other side supports.
So I guess it will work if all your zLinux servers within the same vlan supports jumboframes. I'm not an expert here, maybe someone else can verify. /Tore _________________________________________________ Tore Agblad System programmer, Volvo IT certified IT Architect Volvo Information Technology Infrastructure Mainframe Design & Development, Linux servers Dept 4352 DA1S SE-405 08, Gothenburg Sweden Telephone: +46-31-3233569 E-mail: [email protected] http://www.volvo.com/volvoit/global/en-gb/ -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Martin, Terry R. (CMS/CTR) (CTR) Sent: den 10 november 2011 13:54 To: [email protected] Subject: Re: MTU size in z/Linux Hi Thanks. After researching I found that the default MTU size on the 10G OSA is 8992. So trying at 9000 or anything higher than the 8992 on z/Linux is a moot point. Thanks again for the information. Btw, there was nothing that I had to do from the z/VM standpoint or TCP/IP on z/VM. The TCP/IP stack on the z/Linux guest is where the MTU size was set for this. The main thing in our case was that the Jumbo Frame support on our CISCO switch was not enabled once that was enabled we were able to start transferring Jumbo Frames. Thank You, Terry Martin Principal Systems Engineer Lockheed Martin CMS - CITIC 3300 Lord Baltimore Drive, Suite 200, 21244 Engineering Computing Mainframe Support Cell - 443 632-4191 -----Original Message----- From: Linux on 390 Port [mailto:[email protected]] On Behalf Of Ursula Braun Sent: Thursday, November 10, 2011 3:30 AM To: [email protected] Subject: Re: MTU size in z/Linux Terry, when changing the MTU value for a qeth device, the qeth driver does some checking against the the maximum value allowed. This value depends on the type of the qeth device (OSA or HiperSockets), but in both cases the hardware / firmware defines the maximum allowed value. Regards, Ursula Braun, IBM Germany On Wed, 2011-11-09 at 12:28 -0500, Martin, Terry R. (CMS/CTR) (CTR) wrote: > Hi > > It does not seem to let us specify an MTU higher than 8192. The > question is can we specify a MTU size of 9000 or 9200 > > Thank You, > > Terry Martin > Principal Systems Engineer > Lockheed Martin > CMS - CITIC > 3300 Lord Baltimore Drive, Suite 200, 21244 Engineering Computing > Mainframe Support Cell - 443 632-4191 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390 ---------------------------------------------------------------------- For more information on Linux on System z, visit http://wiki.linuxvm.org/
