`SW_AN`

Enable/Disable SW AN Thread

SW_AN

Shortest form: swan.

Show, start or stop the software auto-negotiation (SW AN) thread of the unit. The SW AN thread runs IEEE auto-negotiation in software for SerDes cores that cannot do it in hardware.

With no argument the command prints SW AN is enabled on unit <n> or SW AN is disabled on unit <n>. One argument turns the thread on or off. The built-in help shows [on] [off]; the shell actually accepts on, enable or yes to start the thread and off, disable or no to stop it. These words must be typed in full. Any other word prints unit: <n> SW_AN Invalid argument.

On a chip without software auto-negotiation support the command prints <cmd>: Error: SW Autoneg is not supported on this platform and does nothing. Trident 3 is such a chip: on a SONiC Trident 3 switch SW_AN fails this way, followed by the SAI front-end’s Failed to execute the diagnostic command line.

Without an argument the command is read-only. On chips that support it, on and off change SDK state that SONiC does not know about, and stopping the thread on a platform that needs it can keep links from coming up after a cable or speed change.

Hardware-validated

drivshell> SW_AN
SW_AN: Error: SW Autoneg is not supported on this platform

Failed to execute the diagnostic command. Error: Operation failed.

SW_AN on

Start the SW AN thread. enable and yes do the same. This changes SDK state behind SONiC.

Unvalidated

drivshell> SW_AN on

SW_AN off

Stop the SW AN thread. disable and no do the same. This changes SDK state behind SONiC.

Unvalidated

drivshell> SW_AN off

Built-in help

Parameters: [on] [off]