6.7

Table Of Contents
3 Click Edit and select the Virtual Hardware tab in the dialog box displaying the settings.
4 Expand the Network adapter section. 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 From the New device drop-down menu, select Network and click Add.
7 From the Adapter Type drop-down menu, select VMXNET 2 (Enhanced) or VMXNET 3.
8 Set the network settings to the ones recorded for the old network adapter.
9 Set the MAC Address to Manual, and type the MAC address that the old network adapter was using.
10 Click OK.
What to do next
n
Check that the enhanced VMXNET adapter is connected to a standard switch or to a distributed
switch with jumbo frames enabled.
n
Inside the guest operating system, configure the network adapter to allow jumbo frames. See the
documentation of your guest operating system.
n
Configure all physical switches and any physical or virtual machines to which this virtual machine
connects to support jumbo frames.
TCP Segmentation Ooad
Use TCP Segmentation Offload (TSO) in VMkernel network adapters and virtual machines to improve the
network performance in workloads that have severe latency requirements.
TSO on the transmission path of physical network adapters, and VMkernel and virtual machine network
adapters improves the performance of ESXi hosts by reducing the overhead of the CPU for TCP/IP
network operations. When TSO is enabled, the network adapter divides larger data chunks into TCP
segments instead of the CPU. The VMkernel and the guest operating system can use more CPU cycles
to run applications.
To benefit from the performance improvement that TSO provides, enable TSO along the data path on an
ESXi host including physical network adapters, VMkernel and guest operating system. By default, TSO is
enabled in the VMkernel of the ESXi host , and in the VMXNET 2 and VMXNET 3 virtual machine
adapters.
For information about the location of TCP packet segmentation in the data path, see VMware Knowledge
Base article Understanding TCP Segmentation Offload (TSO) and Large Receive Offload (LRO) in a
VMware environment.
Enable or Disable Software TSO in the VMkernel
If a physical network adapter experiences problems with TSO, you can temporarily enable the software
simulation of TSO in the VMkernel until you troubleshoot the problems.
vSphere Networking
VMware, Inc. 164