Configuring Remote Port MirroringRemote port mirroring requires a source session (monitored ports on different source switches), a reserved tagged VLAN fortransporting mirrored traffic (configured on source, intermediate, and destination switches), and a destination session (destinationports connected to analyzers on destination switches).Configuration NotesWhen 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 intermediatetransport session for a reserved VLAN at the same time for multiple remote-port mirroring sessions. You can enable and disableindividual mirroring sessions.• BPDU monitoring is not required to use remote port mirroring.• A remote port mirroring session mirrors monitored traffic by prefixing the reserved VLAN tag to monitored packets so that theyare copied to the reserve VLAN.• Mirrored traffic is transported across the network using 802.1Q-in-802.1Q tunneling. The source address, destination address andoriginal VLAN ID of the mirrored packet are preserved with the tagged VLAN header. Untagged source packets are tagged withthe reserve VLAN ID.• The RPM VLAN can’t be a Private VLAN.• The RPM VLAN can be used as GVRP VLAN.• The L3 interface configuration should be blocked for RPM VLAN.• The member port of the reserved VLAN should have MTU and IPMTU value as MAX+4 (to hold the VLAN tag parameter).• To associate with source session, the reserved VLAN can have at max of only 4 member ports.• To associate with destination session, the reserved VLAN can have multiple member ports.• Reserved Vlan cannot have untagged portsIn the reserved L2 VLAN used for remote port mirroring:• MAC address learning in the reserved VLAN is automatically disabled.• The reserved VLAN for remote port mirroring can be automatically configured in intermediate switches by using GVRP.• There is no restriction on the VLAN IDs used for the reserved remote-mirroring VLAN. Valid VLAN IDs are from 2 to 4094. Thedefault VLAN ID is not supported.• In mirrored traffic, packets that have the same destination MAC address as an intermediate or destination switch in the pathused by the reserved VLAN to transport the mirrored traffic are dropped by the switch that receives the traffic if the switch hasa L3 VLAN configured.In a source session used for remote port mirroring:• Maximum number of source sessions supported on a switch: 4• Maximum number of source ports supported in a source session: 128• You can configure physical ports and port-channels as sources in remote port mirroring and use them in the same source session.You can use both Layer 2 (configured with the switchport command) and Layer 3 ports as source ports. You can optionallyconfigure one or more source VLANs to specify the VLAN traffic to be mirrored on source ports.• You can use the default VLAN and native VLANs as a source VLAN.• You cannot configure the dedicated VLAN used to transport mirrored traffic as a source VLAN.• Egressing remote-vlan packets are rate limited to a default value of 100 Mbps.In a destination session used for remote port mirroring:• Maximum number of destination sessions supported on a switch: 64• Maximum number ports supported in a destination session: 64.• You can configure any port as a destination port.550 Port Monitoring
