do you have more details, I have the same issue. I have a very slow network performance after upgrade to 126.96.36.199.1.
The following solves the issue also for me:
ldm set-vsw linkprop=phys-state trunk-vsw1
ldm set-vsw mtu=9216 trunk-vsw1
trunk-vsw1 is build on a DLMP-aggregation.
But I don't really understand why an MTU of 9216 fixes the issue, on the rest of the network we only use an MTU of 1500.
It seams that the issue is related to Bug 17161950 - vnet: lso packets are silently dropped in vlan config This is causing the problem. The recommended workaround is:
"edit /etc/system in guest with vnet:
set vnet:vnet_enable_lso = 0