Configuring the receive checksum offload feature

Ubuntu 22.04 LTS LPAR mode z/VM guest

A checksum calculation is a form of redundancy check to protect the integrity of data.

Procedure

The qeth device driver supports offloading checksum calculations on inbound packets (receive) to the OSA feature.

To enable or disable checksum calculations by the OSA feature, issue a command of this form:

# ethtool -K <interface_name> rx <value>

where <value> is on or off.

To let the OSA feature calculate the inbound checksum for network device encf500, issue
```
# ethtool -K encf500 rx on
```
To let the host CPU calculate the inbound checksum for network device encf500, issue
```
# ethtool -K encf500 rx off
```