[Solved] WAN out speeds only 1/5 of UP bandwidth 2.3.1-release-p5

[padenom]

Hi,

I had noticed this earlier (before the p5 release) but only confirmed now. My WAN out speeds are only reaching 2 Mbps whereas I am subscribed to 10 Mbps. I verified by removing directly connecting my laptop with the modem.

Infrastructure:
SuperMicro based PC with 4 network ports (Intel) running Xenserver 6.5.
I have used separate physical ports for WAN (xn0) and LAN (xn1) and xn2 as port for Xen management.
WAN in speeds are getting close the subscribed bandwith 25Mbps. But WAN out hovers around 2 Mbps only.

Under System > Advanced > Networking, I do have "Hardware checksum offload", "TCP segmentation  offload" and "Disable hardware large receive offload" checked.

What else can I check to get my WAN out working close to 10Mbps?

Thanks in advance.

[padenom]

Solution:
Disabled offload checksum on transmission for the virtual interface in Xen (LAN interface). Up/Down speeds are both as expected.