Jumbo Frames

[anthonymeluso]

OK having a tough time understanding the requirements for Jumbo Frames to work through the network. All our servers will be configured for jumbo frames. So will our switches.

Now I'm worried about the other 500 machines. Would I have to go to each machine to turn on jumbo frames. Or would the NIC recognize the speed and continue the transmission with the 9K MTU size. Or will it go back to 1.5K MTU

All servers are Windows 2008 and the clients are a mix of Windows 7 and Windows XP

 

[jimbopalmer]

All devices on a network with Jumbo Frames must allow Jumbo Frames.

If you need Jumbo Frames because you have old servers with weak CPUs, I would try real Server NICs first. If the traffic is Server to Server, you could build a separate network using Jumbo Frames. Then you would not need 500 NICs for the users.

http://www.intel.com/Assets/PDF/prodbrief/320116.pdf

as an example, notice how many features are designed to reduce interrupts and offload the CPU. Using a real server NIC may well solve your problems without 500 user NICs that allow Jumbo Frames.

I tried to remain child-like, all I acheived was childish.

 

[cajuntank]

Your switch will probably be your answer, but what you'll have to do is put you servers on their own separate VLAN. There is no autonegotiation for jumbo-frames, so you have to make a decision "yes or no" and if "Yes" then every device on that subnet/VLAN would have to be "Yes" as well.
So the way to fix this is to create a separate subnet or VLAN just for you servers, set the VLAN's interface on the switch to do jumbo-frames, set the server's NIC's to jumbo-frames, and assign those server ports on the switch to that new VLAN. This of course assumes you have a L3 switch with that capability.

Honestly, I don't think you will find any performance increase that your thinking you will get due to the profile of traffic. What I mean is the TCPIP traffic the clients ask from the server and the traffic the servers offer the client are back and forth, little bits. Where you would see a perfomance increase would be the creation of a jumbo-frame network for a SAN or dedicated backup scenario. That profile of traffic transmits large blocks of data, where the other is a more constant back and forth little bits of data. This constant back and forth little bits of data would cause overhead and re-transmits to occur thus making any performance gains...null.