Mina moussa wrote:
Hi All,
We are seing frames being dropped on some interfaces on our LAN, these interfaces are dropping jumbo frames.
What my question is, is there any issue with just increasing the MTU to allow jumbo frames on the LAN?
Its our LAN so there is no business reason to stop users from sending jumbo frames?
Jumbo frames require larger amounts of memory on your switch to buffer - especially if the DF (don't fragment) bit is set - and if the DF bit is not set, then the switch has to work slightly harder to re-assemble them before delivery, which can add CPU overhead.
The question you should be asking is *why* are your users sending jumbo frames? Most normal office applications will never need to use a jumbo - usually frames that large are reserved for real time, high definition video or really, really big file transfers (if the applications doing the transfer support it) - the benefits for anything else are marginal. Also, a lot of NIC's, especially in-built ones, don't support jumbo frames - so the chances of a frame being sent which the receiver can't accept are higher.
Provided your switches aren't overly loaded, then there shouldn't be a noticable effect in enabling jumbo frames across your network - but remember you have to enable them *everywhere* - every interface (layer 2 or layer 3) as well as the maximum system MTU.
Cheers.
