Jumbo Frames and connecting non-jumbo Switches

[criitdept]

All,

I wander if you can help with this.

I currently have 4 3560 switches connected in a Mesh topology. These are all set to use Jumbo Frames and so are all the Servers that are connected to these.

I now need to connect a 2950 switch to 2 of the 3560's which will have only desktop computers connected to it but i do not want to configure Jumbo Frames on this and any of the desktops.

Can this be done with out causing any problems?

Thanks for you help

James

[smitesh kharecha]

Hi James,

Can you tell us why you require Jumbo frames ??

Well, as far as compatibility is concerns, unless you are not running Q-in-Q, there won't be any major issue; apart from if any frame comes which is larger than default MTU of 2950 will be discarded.

HTH,

Smitesh

PS: Please rate helpful posts...

[criitdept]

Thanks for the quick response.

I didn't really want to go into the switch setup as it is actually 10 switches with a few VLANs.

One of these VLANs is a Storage VLAN and is the reason I want to use Jumbo Frames, so that i can get the most out of my iSCSI SANS.

To do so, I have had to enable Jumbo Frames and as these switches only allow jumbo frames on or off (as aposed to per port or vlan) then i need to enable this on all 1000Mbps devices.

I have just realised that I have not enable Jumbo on the switches for anything that is connected at 10/100Mbps and the 2950 switches are only capable of 10/100Mbps.

As this is the case, does this mean that I do not have to change anything for these switches to connect and operate without causing any discards or problems?

Thanks

James

[smitesh kharecha · Accepted solution]

Hi James,

Yup if opposite port is not able to send jumbo frames, there is no need to enable jumbo frames on 2950...

HTH,

Smitesh

PS: Please rate helpful posts...