Cisco 7604 Configuration Manual page 881

Chapter 52 Configuring Local SPAN, RSPAN, and ERSPAN
Understanding How Local SPAN, RSPAN, and ERSPAN Work
RSPAN Overview
RSPAN supports source ports, source VLANs, and destination ports on different routers, which provides
remote monitoring of multiple routers across your network (see Figure 52-2).
RSPAN consists of an RSPAN source session, an RSPAN VLAN, and an RSPAN destination session.
You separately configure RSPAN source sessions and destination sessions on different routers. To
configure an RSPAN source session on one router, you associate a set of source ports or VLANs with an
RSPAN VLAN. To configure an RSPAN destination session on another router, you associate the
destination ports with the RSPAN VLAN.
The traffic for each RSPAN session is carried as Layer 2 nonroutable traffic over a user-specified RSPAN
VLAN that is dedicated for that RSPAN session in all participating routers. All participating routers
must be trunk-connected at Layer 2.
RSPAN source sessions do not copy locally sourced RSPAN VLAN traffic from source trunk ports that
carry RSPAN VLANs. RSPAN source sessions do not copy locally sourced RSPAN GRE-encapsulated
traffic from source ports.
Each RSPAN source session can have either ports or VLANs as sources, but not both.
The RSPAN source session copies traffic from the source ports or source VLANs and switches the traffic
over the RSPAN VLAN to the RSPAN destination session. The RSPAN destination session switches the
traffic to the destination ports.
Figure 52-2 RSPAN Configuration
Destination switch
Switch D
(data center)
D1
D2
Layer 2 trunk
Probe
C3
Intermediate switch
Switch C
(distribution)
C2
C1
Layer 2 trunk Layer 2 trunk
A3
B4
Source switch(es)
Switch B
Switch A
(access)
A1 A2
B1 B2 B3
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
52-3
OL-4266-08