PERSIST

Command

PERSIST -- Display / Set the persist value for a port.

Synopsis

PER[SIST] <port> [0-255]

Description

The PERSIST command is used to display and set the PERSIST value for a port. This is the "probability to transmit", used as part of the CSMA channel access procedure. A low value is used when there are several stations sharing the channel, giving each a fair chance to transmit. A high value is used when the channel isn't shared. The optimum setting is 256/n where n is the number of station sharing the channel.

Options

If the command is used with a single numeric argument, the current setting for that port number is displayed.

If two arguments are supplied, the PERSIST value for the port specified by the first is set to the value of the second. The new setting remains in force until changed again or until the router is restarted, in which case the value specified in the XROUTER.CFG file will apply.

Examples

PERSIST 5        - Display current PERSIST value for port 5
PERSIST 5 64     - Set port 5 PERSIST to 64

Note

On KISS ports, you should allow up to 5 minutes for a new setting to become active.

Availability

The PERSIST command is available only to sysops.

See also

SLOTTIME(2) -- CSMA interval timer