On Tuesday, 02/12/2002 at 01:42 PST, Marcy Cortes <[EMAIL PROTECTED]> wrote: > Now, one more question! In the TCP/IP P&C manual, p.508 lists > some recommended MTU sizes for various types of interfaces. What's > a good MTU size for guest lan? (our primary app at this point > is apache webserving).
For guests that communicate with *each other* on the guest LAN, a large MTU is best. When routing traffic to a real LAN, use the MTU of the real LAN. Otherwise you get packet fragmentation which just steals cycles from the machine. Linux had "dynamic path MTU discovery" so the apache server will automatically discover the best MTU to use. With this model, feel free to use a larger MTU on the guest LAN. Fragmentation will occur initially, but will disappear as Linux reduces the MTU automatically. Just make sure the initial MTU size specified on the apache server matches the MTU specified on VM TCP/IP. Regards, Alan IBM Senior Software Engineer z/VM Development, Endicott, NY Phone 607.752.6027 fax 607.752.1497 t/l 852
