6.7

Table Of Contents
Procedure
u
Run these esxcli network nic software set console commands to enable or disable the
software simulation of TSO in the VMkernel.
n
Enable the software simulation of TSO in the VMkernel.
esxcli network nic software set --ipv4tso=1 -n vmnicX
esxcli network nic software set --ipv6tso=1 -n vmnicX
n
Disable the software simulation of TSO in the VMkernel.
esxcli network nic software set --ipv4tso=0 -n vmnicX
esxcli network nic software set --ipv6tso=0 -n vmnicX
where X in vmnicX represents the number of the NIC ports on the host.
The configuration change persists across host reboots.
Determine Whether TSO Is Supported on the Physical Network
Adapters on an ESXi Host
Examine whether a physical network adapter offloads TCP/IP packet segmentation when you estimate
the networking performance on a host that runs latency-sensitive workloads. If a physical network adapter
supports TSO, then TSO is enabled by default.
Procedure
u
Run this esxcli network nic software get console command to determine whether TSO is
enabled on the physical network adapters on a host.
esxcli network nic tso get
Enable or Disable TSO on an ESXi Host
Enable TCP Segmentation Offload (TSO) on the transmission path to have the NIC divide larger data
chunks into TCP segments. Disable TSO to have CPU perform TCP segmentation.
By default, a host uses hardware TSO if its physical adapters support it.
Procedure
1 In the vSphere Web Client, navigate to the host.
2 On the Configure tab, expand System.
3 Click Advanced System Settings.
4 Edit the value of the Net.UseHwTSO parameter for IPv4 and of Net.UseHwTSO6 for IPv6.
n
To enable TSO, set Net.UseHwTSO and Net.UseHwTSO6 to 1.
n
To disable TSO, set Net.UseHwTSO and Net.UseHwTSO6 to 0.
vSphere Networking
VMware, Inc. 165