Cisco Systems WSC4500X16SFP Configuring RSPAN

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Software Configuration Guide—Release 12.2(25)SG
OL-7659-03
Chapter37 Configuring SPAN and RSPAN
Configuring RSPAN
Configuring RSPAN
This section describes how to configure RSPAN on your switch and it contains this configuration
information:
•RSPAN Configuration Guidelines, page 37-16
•Creating an RSPAN Session, page 37-17
•Creating an RSPAN Destination Session, page 37-18
•Creating an RSPAN Destination Session and Enabling Ingress Traffic, page 37-19
•Removing Ports from an RSPAN Session, page 37-21
•Specifying VLANs to Monitor, page 37-22
•Specifying VLANs to Filter, page 37-23
RSPAN Configuration Guidelines
Follow these guidelines when configuring RSPAN:
Note Since RSPAN VLANs have special properties, you should reserve a few VLANs across your network
for use as RSPAN VLANs; do not assign access ports to these VLANs.
Note You can apply an output access control list (ACL) to RSPAN traffic to selectively filter or monitor
specific packets. Specify these ACLs on the RSPAN VLAN in the RSPAN source switches.
•RSPAN sessions can coexist with SPAN sessions within the limits described in the “SPAN and
RSPAN Session Limits” section on page 37-6.
•For RSPAN configuration, you can distribute the source ports and the destination ports across
multiple switches in your network.
•RSPAN does not support BPDU packet monitoring or other Layer 2 switch protocols.
•The RSPAN VLAN is configured only on trunk ports and not on access ports. To avoid unwanted
traffic in RSPAN VLANs, make sure that all participating switches support the VLAN remote-span
feature. Access ports on the RSPAN VLAN are silently disabled.
•You should create an RSPAN VLAN before configuring an RSPAN source or destination session.
•If you enable VTP and VTP pruning, RSPAN traffic is pruned in the trunks to prevent the unwanted
flooding of RSPAN traffic across the network for VLAN-IDs that are lower than 1005.
•Because RSPAN traffic is carried across a network on an RSPAN VLAN, the original VLAN
association of the mirrored packets is lost. Therefore, RSPAN can only support forwarding of traffic
from an IDS device onto a single user-specified VLAN.