Administrator Guide

• A remote port mirroring session mirrors monitored traffic by prefixing the reserved VLAN tag to monitored packets so that they are
copied to the reserve VLAN.
• Mirrored traffic is transported across the network using 802.1Q-in-802.1Q tunneling. The source address, destination address and
original VLAN ID of the mirrored packet are preserved with the tagged VLAN header. Untagged source packets are tagged with the
reserve VLAN ID.
• You cannot configure a private VLAN or a GVRP VLAN as the reserved RPM VLAN.
• 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 ports
In 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. The default
VLAN ID is not supported.
• In mirrored traffic, packets that have the same destination MAC address as an intermediate or destination switch in the path used by
the reserved VLAN to transport the mirrored traffic are dropped by the switch that receives the traffic if the switch has a L3 VLAN
configured.
In a source session used for remote port mirroring:
• You can configure any port as a source port in a remote-port monitoring session with a maximum of three source ports per port pipe.
• Maximum number of source sessions supported on a switch: 3
When you configure remote port mirroring, you can create a maximum of 3 source RSPAN sessions with port mirroring direction as
either rx or tx. If you want to configure port mirroring for both directions (tx and rx), you can configure a maximum of 2 RSPAN
sessions with one monitor session for both directions and the other session with only one direction.
• 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 optionally configure 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. To change the mirroring rate, configure rate-limit within
the RPM session.
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.
• You can configure additional destination ports in an active session.
• You can tunnel the mirrored traffic from multiple remote-port source sessions to the same destination port.
• By default, destination port sends the mirror traffic to the probe port by stripping off the rpm header. We can also configure the
destination port to send the mirror traffic with the rpm header intact in the original mirror traffic..
• By default, ingress traffic on a destination port is dropped.
Restrictions
When you configure remote port mirroring, the following restrictions apply:
• You can configure the same source port to be used in multiple source sessions.
• You cannot configure a source port channel or source VLAN in a source session if the port channel or VLAN has a member port that is
configured as a destination port in a remote-port mirroring session.
• A destination port for remote port mirroring cannot be used as a source port, including the session in which the port functions as the
destination port.
• A destination port cannot be used in any spanning tree instance.
• The reserved VLAN used to transport mirrored traffic must be a L2 VLAN. L3 VLANs are not supported.
Port Monitoring
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