Nexus 5548 - Jumbo Frames

[theitmedic]

I have a Nexus 5548 installed (layer 2 device only) with several 10G ports supporting IBM P770 systems and a TSM (Tivoli Storage Manager) system on a single VLAN. All of the Nexus 5548 ports are configured for jumbo frames. I was ask to install a new server on the same VLAN as the others but as 1G port without jumbo frames to allow communications with the TSM server.

I'm assuming that the 1G port for this new server without jumbo frames configured on the Nexus 5548 will not be unable to communicate with the TSM server that is on the same VLAN with it's Nexus 5548 10G port configure using jumbo frames. Can someone validate that my assumptions are true or false

Thanks

[siddhartham]

Is there any reason for your assumption?. We have many servers connectted 3560 switches which are talking to TSM connected to a 5010.we enabled jumbo frames on 5510 but don't have that option on 3560.

[theitmedic]

Is it all layer 2, no layer 3 routing between them?

[Jerry Ye]

Jumbo frame in Nexus 5500 is under network qos, this means it will apply to all interfaces (10GE and 1GE).

When you said no jumbo frame for the server, what do you mean? Do you mean you it will be default on the NIC level.

Regards,

jerry

[theitmedic]

We want to set the Nexus 10G ports to jumbo frames and the 1G port set to no jumbo frames. I don't think the servers will be able to talk to one another between the ports that have jumbo frames set and the port that don't have jumbo frames set.

[Jerry Ye]

First, it is very difficult to set 10GE only ports to jumbo and 1GE ports to non-jumbo. You need to do some ACL matching to accomplish this on the Nexus 5500 (once again the policy is under network qos and it is system level configuration).

Second, I think you've mis-understood the concept of MTU. Once again, MTU is Maximum Transmission Unit, not Receive. When a server not able to send jumbo packet (transmit) doesn't mean that it will not able to receive jumbo packet it is depends on the NIC driver.

Regards,

jerry