Configuring the Flow Control

If a node on an Ethernet network sends packets faster than the receive node can handle, then the overwhelmed node can send pause frame to the sender pausing the sender for a short time. This process is called Flow Control.

If for any reason Flow Control is undesired it can be disabled using the ethtool. The example below is applied to the Intel e1000.

To list current status of flow control on the eth0 device, run the following command:

#ethtool –a eth0

The output:

Pause parameters for eth0:
Autonegotiate: on
RX: on
TX: on

To disable the Flow Control on the Tx and Rx, you need first to disable the auto-negotiations:

# ethtool --pause eth0 autoneg off

Then we need to disable the Flow Control for the send and receive traffic:

# ethtool --pause tx off rx off

Check again the status of Flow Control. All fields should be set to off:

# ethtool –a eth0
Pause parameters for eth0:
Autonegotiate: off
RX: off
TX: off

References

Ethernet flow control
Source: http://en.wikipedia.org