Reflector Port; Ingress Span; Egress Span; Vspan - Cisco WS-C4003 - Catalyst 4000 Chassis Switch Software Configuration Manual

Chapter 25 Configuring SPAN and RSPAN

Reflector Port

The reflector port is the mechanism you use to copy packets onto an RSPAN VLAN. The reflector port
forwards only the traffic from the RSPAN source session with which it is affiliated. Any device
connected to a port set as a reflector port loses connectivity until the RSPAN source session is disabled.
If the bandwidth of the reflector port is not sufficient to handle the traffic from the corresponding source
ports, the excess packets are dropped. A 10/100 port reflects at 100 Mbps. A Gigabit port reflects at
1 Gbps. A blocking gigabit port reflects at a slightly lower rate.
The reflector port cannot be an EtherChannel port, does not trunk, and cannot do protocol filtering. A
port used as a reflector port cannot be a SPAN source or destination port, nor can a port be a reflector
port for more than one session at a time. Spanning tree is automatically disabled on a reflector port; the
port remains in the forwarding state even though the port is in loopback mode.
The following ports cannot be used as reflector ports:
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The SPAN line in the output of the show port capabilities command indicates whether a port can be
used as a reflector port.

Ingress SPAN

Ingress SPAN copies network traffic received by the source ports for analysis at the destination port.

Egress SPAN

Egress SPAN copies network traffic transmitted from the source ports for analysis at the destination port.

VSPAN

You can use VLAN-based SPAN (VSPAN) to analyze the network traffic in one or more VLANs. You
can configure VSPAN in a bi-directional mode (ingress and egress). All the ports in the source VLANs
become operational source ports for the VSPAN session. The destination port or the reflector port, if they
belong to any of the administrative source VLANs, are excluded from the operational source. If you add
or remove ports from the administrative source VLANs, the operational sources modify accordingly.
Use the following guidelines for VSPAN sessions:
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Gigabit uplink ports on the WS-4013 Supervisor II
Gigabit uplink ports on the 2980G-A
Gigabit ports on the WS-4232-L3 module
Trunk ports are included as source ports for VSPAN sessions, but only the VLANs that are in the
Admin source list are monitored, provided these VLANs are active for the trunk.
An inband port is not included as Oper source for VSPAN sessions.
When a VLAN is cleared, it is removed from the source list for VSPAN sessions.
A VSPAN session is disabled if the Admin source VLANs list is empty.
Inactive VLANs are not allowed for VSPAN configuration.
A VSPAN session is made inactive if any of the source VLANs become RSPAN VLANs.
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
Understanding How SPAN and RSPAN Work
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