>From Cameron Seader: > I am getting an error when starting my hipersocket up. > SIOCSIFMTU: Invalid argument > Why am i getting this error, shouldn't it take '65535' as a valid mtu size? > I never had this problem on SLES 8, did something change? > I'm also noticeing that my mtu is being dropped to 57344 according to ifconfig. > why is it dropping down to this mtu size. > Any thoughts, any ideas?
The largest Maximum Frame Size (not Maximum Transmission Unit) for HiperSockets is 64K (and that is only if you have configured the chpid for 64K). The largest MTU you can use with a 64K buffer is 56K because the hardware interface reserves 8K for its own purposes. I suspect you might (sometimes) get away with using a larger MTU size in some cases: (1) If nobody actually sent more than 56K in a single frame you would not notice a problem. (2) If you sent more than 56K but the device didn't need all of its work area... no problem. MTU 56K is the right limit for a 64K MFS buffer. Dennis ---------------------------------------------------------------- Dennis Musselwhite ([EMAIL PROTECTED]) +1(607)429-3831 z/VM Development -- CP Network Simulation -- IBM Endicott NY ---------------------------------------------------------------------- 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
