Span Sessions - Cisco IE-4000 Software Configuration Manual

Configuring SPAN and RSPAN
Information About SPAN and RSPAN
Figure 70 Example of RSPAN Configuration
must support RSPAN VLAN
Switch A

SPAN Sessions

SPAN sessions (local or remote) allow you to monitor traffic on one or more ports, or one or more VLANs, and send the
monitored traffic to one or more destination ports.
A local SPAN session is an association of a destination port with source ports or source VLANs, all on a single network
device. Local SPAN does not have separate source and destination sessions. Local SPAN sessions gather a set of ingress
and egress packets specified by the user and form them into a stream of SPAN data, which is directed to the destination
port.
RSPAN consists of at least one RSPAN source session, an RSPAN VLAN, and at least one RSPAN destination session.
You separately configure RSPAN source sessions and RSPAN destination sessions on different network devices. To
configure an RSPAN source session on a device, you associate a set of source ports or source VLANs with an RSPAN
VLAN. The output of this session is the stream of SPAN packets that are sent to the RSPAN VLAN. To configure an RSPAN
destination session on another device, you associate the destination port with the RSPAN VLAN. The destination session
collects all RSPAN VLAN traffic and sends it out the RSPAN destination port.
An RSPAN source session is very similar to a local SPAN session, except for where the packet stream is directed. In an
RSPAN source session, SPAN packets are relabeled with the RSPAN VLAN ID and directed over normal trunk ports to the
destination switch.
An RSPAN destination session takes all packets received on the RSPAN VLAN, strips off the VLAN tagging, and presents
them on the destination port. Its purpose is to present a copy of all RSPAN VLAN packets (except Layer 2 control packets)
to the user for analysis.
destination ports
Switch C
Intermediate switches
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source
session A
RSPAN
source ports
RSPAN
RSPAN
destination
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RSPAN
VLAN
Switch B
RSPAN
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