Cisco WS-SUP32-GE-3B - Supervisor Engine 32 Software Configuration Manual page 782

Understanding How Local SPAN, RSPAN, and ERSPAN Work
These sections provide an overview of local SPAN, RSPAN, and ERSPAN:
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Local SPAN Overview
A local SPAN session is an association of source ports and source VLANs with one or more destination
ports. You configure a local SPAN session on a single switch. Local SPAN does not have separate source
and destination sessions.
Local SPAN sessions do not copy locally sourced RSPAN VLAN traffic from source trunk ports that
carry RSPAN VLANs. Local SPAN sessions do not copy locally sourced RSPAN GRE-encapsulated
traffic from source ports.
Each local SPAN session can have either ports or VLANs as sources, but not both.
Local SPAN copies traffic from one or more source ports in any VLAN or from one or more VLANs to
a destination port for analysis (see
Ethernet port 5 (the source port) is copied to Ethernet port 10. A network analyzer on Ethernet port 10
receives all traffic from Ethernet port 5 without being physically attached to Ethernet port 5.
Figure 48-1
E1
RSPAN Overview
RSPAN supports source ports, source VLANs, and destination ports on different switches, which
provides remote monitoring of multiple switches across your network (see
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 switches. To
configure an RSPAN source session on one switch, you associate a set of source ports or VLANs with
an RSPAN VLAN. To configure an RSPAN destination session on another switch, you associate the
destination ports with the RSPAN VLAN.
Catalyst Supervisor Engine 32 PISA Cisco IOS Software Configuration Guide, Release 12.2ZY
48-2
Local SPAN Overview, page 48-2
RSPAN Overview, page 48-2
ERSPAN Overview, page 48-3
Monitored Traffic, page 48-4
Example SPAN Configuration
1 2 3 4 5 6 7 8 9 10 11 12
E6 E7
E5 E8
E4 E9
E3
E2
Network analyzer
Chapter 48
Figure 48-1). For example, as shown in
Port 5 traffic mirrored
on port 10
E11
E12
E10
Configuring Local SPAN, RSPAN, and ERSPAN
Figure 48-1, all traffic on
Figure 48-2).
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