Configuring Symmetrical Flow Control

Symmetrical flow control (SFC) is globally disabled by default. However, because flow control is enabled by default on all ports, these ports will always honor received 802.3x Pause frames, irrespective of whether symmetrical flow control is enabled or disabled.
To configure symmetrical flow control, priority flow control (PFC) must be disabled.
  1. Enter global configuration mode.
    device# configure terminal
  2. Enable symmetrical flow control globally or on all priorities.
    device(config)# symmetrical-flow-control enable

    Enables SFC on priorities from 0 through 4. Enabling SFC using the symmetrical-flow-control enable command is recommended.

    device(config)# symmetrical-flow-control enable all-priorities
    Caution: Enabling SFC on all priorities is not recommended as it can cause network instability.
  3. Enable flow control in various modes in interface configuration mode.
    device(config)# interface ethernet 1/1/1
device(config-if-e1000-1/1/1)# flow-control generate-only
device(config-if-e1000-1/1/1)# flow-control honor-only
device(config-if-e1000-1/1/1)# flow-control both

The following example shows how to configure symmetrical flow control for priorities from 0 through 4 in generate-only mode.

device# configure terminal
device(config)# symmetrical-flow-control enable 
device(config)# interface ethernet 1/1/1
device(config-if-e1000-1/1/1)# flow-control generate-only
Parent topic: Symmetrical Flow Control