Flow Control

This configuration option is only available on devices that has support for this functionality.

Introduction

Flow control is a mechanism for stopping transmission of data on ports. The goal is to avoid packet loss when network is congested. This is accomplished by the MAC sending pause frames to the sender. Only full-duplex ports may send pause frames. For flow control to function both the ingress port (that sends the pause frames) and egress port (that is congested) on a switch needs to be configured with this option, and of course the port that should pause sending.

Configuration

example:/#> configure
example:/config/#> port ethX
example:/config/port-ethX/#> help flow-control
Syntax:
        [no] flow-control 
Usage:
        Set flow control, sending and reacting to pause frames.

        off      : Disable        (autoneg = 0, rx = 0, tx = 0)
        autoneg  : Autonegotiate  (autoneg = 1, rx = 1, tx = 1)
        forced   : Forced on      (autoneg = 0, rx = 1, tx = 1)
example:/config/port-ethX/#> flow-control autoneg
example:/config/port-ethX/#> show flow-control
autoneg

Syntax

no flow-control OR flow-control off

Disables flow control.

no

Disable.

flow-control <autoneg|forced>

Enables flow control.

autoneg

Set the port to autonegotiate flow control. Both sides of a link needs to set this for feature to be enabled.

forced

Set the port to force sending of pause frames.