Administrator Guide

In a remote-port mirroring session, monitored traffic is tagged with a VLAN ID and switched on a user-defined, non-routable L2 VLAN.
The VLAN is reserved in the network to carry only mirrored traffic, which is forwarded on all egress ports of the VLAN. Each intermediate
switch that participates in the transport of mirrored traffic must be configured with the reserved L2 VLAN. Remote port monitoring
supports mirroring sessions in which multiple source and destination ports are distributed across multiple switches
Remote Port Mirroring Example
Remote port mirroring uses the analyzers shown in the aggregation network in Site A.
The VLAN traffic on monitored links from the access network is tagged and assigned to a dedicated L2 VLAN. Monitored links are
configured in two source sessions shown with orange and green circles. Each source session uses a separate reserved VLAN to transmit
mirrored packets (mirrored source-session traffic is shown with an orange or green circle with a blue border).
The reserved VLANs transport the mirrored traffic in sessions (blue pipes) to the destination analyzers in the local network. Two
destination sessions are shown: one for the reserved VLAN that transports orange-circle traffic; one for the reserved VLAN that
transports green-circle traffic.
Figure 95. Remote Port Mirroring
Configuring Remote Port Mirroring
Remote port mirroring requires a source session (monitored ports on different source switches), a reserved tagged VLAN for transporting
mirrored traffic (configured on source, intermediate, and destination switches), and a destination session (destination ports connected to
analyzers on destination switches).
Configuration Notes
When you configure remote port mirroring, the following conditions apply:
• You can configure any switch in the network with source ports and destination ports, and allow it to function in an intermediate
transport session for a reserved VLAN at the same time for multiple remote-port mirroring sessions. You can enable and disable
individual mirroring sessions.
• BPDU monitoring is not required to use remote port mirroring.
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Port Monitoring