Reference Guide
Session and VLAN requirements
Remote port monitoring requires a source session (monitored ports on dierent source devices), a reserved tagged VLAN for transporting
monitored trac (congured on source, intermediate, and destination devices), and a destination session (destination ports connected to
analyzers on destination devices).
• Congure any network device with source ports and destination ports and enable it to function in an intermediate transport session for
a reserved VLAN at the same time for multiple remote port monitoring sessions. Enable and disable individual monitoring sessions.
• A remote port monitoring session mirrors monitored trac by prexing the reserved VLAN tag to monitored packets to transmit using
the reserved VLAN.
• The source address, destination address, and original VLAN ID of the mirrored packet are prexed with the tagged VLAN header.
Untagged source packets are tagged with the reserved VLAN ID.
• The member port of the reserved VLAN must have the MTU and IPMTU value as MAX+4 (to hold the VLAN tag parameter).
• To associate with source session, the reserved VLAN can have a maximum of four member ports.
• To associate with destination session, the reserved VLAN can have multiple member ports.
• The reserved VLAN cannot have untagged ports.
Reserved L2 VLAN
• MAC address learning in the reserved VLAN is automatically disabled.
• There is no restriction on the VLAN IDs used for the reserved remote monitoring VLAN. Valid VLAN IDs are from 2 to 4093. The default
VLAN ID is not supported.
• In monitored trac, packets that have the same destination MAC address as an intermediate or destination device in the path used by
the reserved VLAN to transport the mirrored trac are dropped by the device that receives the trac if the device has a L3 VLAN
congured.
Source session
• Congure physical ports and port-channels as sources in remote port monitoring and use them in the same source session. You can use
both L2 (congured with the switchport command) and L3 ports as source ports. Optionally congure one or more source VLANs
to congure the VLAN trac to be monitored on source ports.
• Use the default VLAN and native VLANs as a source VLAN.
• You cannot congure the dedicated VLAN used to transport mirrored trac as a source VLAN.
Layer 2
257