6.0

TCP Segmentation Offload and Jumbo Frames
Using TCP Segmentation Offload (TSO) in a VMkernel network adapter and virtual machines, and jumbo
frames on a vSphere distributed switch or vSphere standard switch, improves the network performance in
virtual machines and infrastructure workloads.
Enable TSO Support for a Virtual Machine
You can enable TSO support on a virtual machine by using an enhanced vmxnet adapter for that virtual
machine.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 Log in to the vSphere Client and select the virtual machine from the inventory panel.
2 Click the Summary tab, and click Edit Settings.
3 Select the network adapter from the Hardware list.
4 Record the network settings and MAC address that the network adapter is using.
5 Click Remove to remove the network adapter from the virtual machine.
6 Click Add.
7 Select Ethernet Adapter and click Next.
8 In the Adapter Type group, select Enhanced vmxnet.
9 Select the network setting and MAC address that the old network adapter was using and click Next.
10 Click Finish and then click OK.
11 If the virtual machine is not set to upgrade VMware Tools at each power on, you must upgrade
VMware Tools manually.
TSO is enabled on a VMkernel interface. If TSO becomes disabled for a particular VMkernel interface, the
only way to enable TSO is to delete that VMkernel interface and recreate it with TSO enabled.
Enable Jumbo Frames for a VMkernel Interface on a vSphere Standard Switch
Jumbo frames reduce the CPU load caused by transferring data. Enable jumbo frames on a VMkernel
network interface by changing the maximum transmission units (MTU) of the VMkernel interface.
Prerequisites
Launch the vSphere Client and log in to a vCenter Server system.
Procedure
1 Log in to the vSphere Client and select a host in the inventory pane.
2 On the host Configuration tab, click Networking.
3 Click Properties for the vSphere standard switch associated with the VMkernel to modify.
4 On the Ports tab, select the VMkernel interface and click Edit.
5 Set the MTU to 9000, and click OK.
vSphere Administration with the vSphere Client
250 VMware, Inc.