Chapter 52
Configuring Local SPAN, RSPAN, and ERSPAN
This example shows how to configure a port as an unconditional IEEE 802.1Q trunk:
Router(config)# interface fastethernet 5/12
Router(config-if)# switchport
Router(config-if)# switchport trunk encapsulation dot1q
Router(config-if)# switchport mode trunk
Router(config-if)# switchport nonegotiate
Configuring Destination Trunk Port VLAN Filtering
In addition to filtering VLANs on a trunk, you can also apply the allowed VLAN list to access ports.
Note
With Release 12.2(18)SXD and later releases, when a destination port is a trunk, you can use the list of
VLANs allowed on the trunk to filter the traffic transmitted from the destination port. (CSCeb01318)
Destination trunk port VLAN filtering removes the restriction that all destination ports receive all the
traffic from all the sources. Destination trunk port VLAN filtering allows you to select, on a per-VLAN
basis, the traffic that is transmitted from each destination trunk port to the network analyzer.
To configure destination trunk port VLAN filtering on a destination trunk port, perform this task:
Command
Step 1
Router# configure terminal
Step 2
Router(config)# interface type
Step 3
Router(config-if)# switchport trunk allowed vlan
{add | except | none | remove} vlan
[, vlan [, vlan [,...]]
1.
type = ethernet, fastethernet, gigabitethernet, or tengigabitethernet
When configuring the list of VLANs allowed on a destination trunk port, note the following information:
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This example shows the configuration of a local SPAN session that has several VLANs as sources and
several trunk ports as destinations, with destination trunk port VLAN filtering that filters the SPAN
traffic so that each destination trunk port transmits the traffic from one VLAN:
interface GigabitEthernet1/1
description SPAN destination interface for VLAN 10
no ip address
switchport
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 10
switchport mode trunk
switchport nonegotiate
OL-4266-08
1
slot/port
The vlan parameter is either a single VLAN number from 1 through 4094, or a range of VLANs
described by two VLAN numbers, the lesser one first, separated by a dash. Do not enter any spaces
between comma-separated vlan parameters or in dash-specified ranges.
All VLANs are allowed by default.
To remove all VLANs from the allowed list, enter the switchport trunk allowed vlan none
command.
To add VLANs to the allowed list, enter the switchport trunk allowed vlan add command.
You can modify the allowed VLAN list without removing the SPAN configuration.
Cisco 7600 Series Router Cisco IOS Software Configuration Guide, Release 12.2SX
Configuring Local SPAN, RSPAN, and ERSPAN
Purpose
Enters global configuration mode.
Selects the destination trunk port to configure.
Configures the list of VLANs allowed on the trunk.
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