Drivers that support jumbo frames can interoperate with drivers that do not support jumbo frames on the same system. This interoperability is possible as long as jumbo frame support is not enabled when you create the virtual switch.
Do not set the mtu property if any guest or service domains that are associated with the virtual switch do not use Logical Domains drivers that support jumbo frames.
Jumbo frames can be enabled by changing the mtu property of a virtual switch from the default value of 1500. In this instance, older driver versions ignore the mtu setting and continue to use the default value. Note that the ldm list output will show the MTU value you specified and not the default value. Any frames larger than the default MTU are not sent to those devices and are dropped by the new drivers. This situation might result in inconsistent network behavior with those guests that still use the older drivers. This applies to both client guest domains and the service domain.
So, while jumbo frames are enabled, ensure that all virtual devices in the Logical Domains network are upgraded to use the new drivers that support jumbo frames. Also ensure that you upgrade to at least Logical Domains Manager 1.2 so that you can configure jumbo frames.