21-8
Catalyst 2950 Desktop Switch Software Configuration Guide
78-14982-01
Chapter 21 Configuring SPAN and RSPAN
Configuring SPAN

SPAN and RSPAN Session Limits

You can configure (and store in NVRAM) a maximum of two SPAN or RSPAN sessions on each switch.
You ca n divide th e two sess io ns b etwee n SPAN, RSPAN sour ce , an d RSPAN destina ti on s essions. You
can configure mu ltiple source ports or sou rce VLAN s for each session.

Default SPAN and RSPAN Configuration

Table 21-1 sh ows the default SPAN an d R SPAN configura tion.

Configuring SPAN

This se ction de scri bes how to c onfigure SPAN o n y our sw itch . It c ont ains thi s con figurat ion
information:
•SPAN Configuration Guidelines, page 21-8
•Creating a SPAN Se ssion and Sp ec ify ing Po rts to M onitor, page 21 -9
•Removing Ports from a SPAN Session, page 21-11
•Specifying V LANs to Moni tor, page 21-12
•Specifying V LANs to Filter, page 21-13

SPAN Configuration Guidelines

Follow these guidelines when configuring SPAN:
•SPAN sessions can coexist with RSPAN sessions within the limits described in the “SPAN and
RSPAN Session Limits” section on page 21-8 .
•The de stinati on port ca nnot be a sour ce port; a sour ce port cannot be a desti nation por t.
•You ca n have only one desti natio n por t pe r SPAN sessi on. You c annot have two SPAN sessi ons
using the same destination port.
•An Ethe rCh anne l po rt c an b e a SPA N so urce po rt; i t c anno t be a SPAN dest inatio n p ort.
•An 802. 1X p ort ca n be a SPA N sou rce por t. You ca n ena ble 8 02.1X o n a p or t t hat i s a SPA N
destination or reflector port; however, 802.1X is disabled until the port is removed as a SPAN
destinat ion or r efl ect or po rt .
•For SPAN source ports, you can mon itor tr ansm itted tr affic for a single port and received traffic for
a seri es or r ang e of p orts or VLA Ns.
Table 21-1 Default SPAN and RSPAN Configuration
Feature Default Setting
SPAN state Disabled.
Source p ort tr affic to moni tor Both re ceived and se nt tr affic (both) ; fo r ad dit iona l
source ports or VLANs, only received (rx) traffic can be
monitored.
Enca psulatio n type (des tinati on port) Native form (no encapsul ation ty pe heade r).