Cisco Catalyst SPAN/RSPAN Configuration

Posted February 12, 2004 by Al Banks in Cisco switch

This tech-recipe provides instructions for SPAN and RSPAN configuration. SPAN mirrors a port within the same switch, while RSPAN mirrors a port in a remote switch.

In CatOS, use the following syntax to establish a SPAN session:

set span (source port|source vlan) (destination port) (rx|tx|both)

Note the following example which will mirror all traffic from 3/1 to 3/2:
set span 3/1 3/2 both

Older workgroup switches follow this syntax to mirror traffic from 1/2 to 1/5.:interface fastethernet 1/5
port monitor 1/2 both

Newer IOS on workgroup switches use the monitor session command:interface fastethernet 1/5
monitor session 1 source interface 1/2 both

ormonitor session 1 source vlan 100 both

For RSPAN, first configure an RSPAN VLAN:set vlan 200 rspan
This VLAN will be distributed over VTP, I would presume.

Then, configure the RSPAN source on the remote switch:set rspan source 3/1 both
orset rspan source 100 both

Finally, a destination must be defined:set rspan destination 4/5

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