Specifications

11-8
System Management Software Configuration Guide for Cisco IE 2000U and Connected Grid Switches
OL-29255-03
Chapter 11 Configuring SPAN and RSPAN
Prerequisites
– To change a VLAN from a UNI-ENI isolated VLAN (the default) to an RSPAN VLAN, enter
the rspan-vlan VLAN configuration command.
– To change a UNI-ENI community VLAN to an RSPAN VLAN, you must first remove the
community VLAN type by entering the no uni-vlan VLAN configuration command.
• STP can run on RSPAN VLAN trunks but not on SPAN destination ports.
Note NNIs support STP by default and you can enable STP on ENIs. UNIs do not support STP.
• An RSPAN VLAN cannot be a private-VLAN primary or secondary VLAN.
It is normal to have multiple RSPAN VLANs in a network at the same time with each RSPAN VLAN
defining a network-wide RSPAN session. That is, multiple RSPAN source sessions anywhere in the
network can contribute packets to the RSPAN session. It is also possible to have multiple RSPAN
destination sessions throughout the network, monitoring the same RSPAN VLAN and presenting traffic
to the user. The RSPAN VLAN ID separates the sessions.
Prerequisites
Review the “Information About SPAN and RSPAN” section on page 11-1 and “SPAN and RSPAN
Interaction with Other Features” section on page 11-9.
Guidelines and Limitations
SPAN Configuration Guidelines
• You can configure a total of two local SPAN sessions or RSPAN source sessions on each switch. You
can have a total of 66 SPAN sessions (local, RSPAN source, and RSPAN destination) on a switch.
• For SPAN sources, you can monitor traffic for a single port or VLAN or a series or range of ports
or VLANs for each session. You cannot mix source ports and source VLANs within a single SPAN
session.
• The destination port cannot be a source port; a source port cannot be a destination port.
• You cannot have two SPAN sessions using the same destination port.
• When you configure a switch port as a SPAN destination port, it is no longer a normal switch port;
only monitored traffic passes through the SPAN destination port.
• Entering SPAN configuration commands does not remove previously configured SPAN parameters.
You must enter the no monitor session {session_number | all | local | remote} global configuration
command to delete configured SPAN parameters.
• For local SPAN, outgoing packets through the SPAN destination port carry the original
encapsulation headers—untagged or 802.1Q—if the encapsulation replicate or encapsulation
dot1q keywords are specified. If the keywords are not specified, the packets are sent in native form.
For RSPAN destination ports, outgoing packets are not tagged.
• You can configure a disabled port to be a source or destination port, but the SPAN function does not
start until the destination port and at least one source port or source VLAN are enabled.