Specifications

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Catalyst 4500 Series Switch Cisco IOS Command Reference—Release IOS XE 3.3.0XO(15.1(1)XO)
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Chapter 2 Cisco IOS Commands for the Catalyst 4500 Series Switches
l2protocol-tunnel
l2protocol-tunne l
To enable protocol tunneling on an interface, use the l2protocol-tunnel command. You can enable
tunneling for the Cisco Disc overy Protocol (CDP), Spanni ng Tree Protocol (STP ), or VLAN Trunking
Protocol (VTP) packets. To disable tunneling on the interface , use the no form of this comma nd.
l2protocol-tunnel [cdp | stp | vtp]
no l2protocol-tunnel [cdp | stp | vtp]
Syntax Description
Defaults T he default is that no Layer 2 protocol packets are tunnele d.
Command Modes Interface configuration mode
Usage Guidelines You must enter this command, wit h or without protocol ty pes, to tunnel Layer 2 packet s.
Layer 2 protocol tunneling acr oss a service-provi der network ensures that La yer 2 information is
propagated across the networ k to all customer locations . When protocol tunnel ing is enabled, prot ocol
packets are encapsulated w ith a well- known Cisco multica st address for transmission across the network.
When the packets reach their destination, the well-known MAC address is replaced by the Layer 2
protocol MAC address.
You can enable Layer 2 proto col tunneli ng for CDP, STP, and V TP individuall y or for all three p rotocols.
Examples This exampl e shows how to enable protocol tunneling for the CDP pac kets:
Switch(config-if)# l2protocol-tunnel cdp
Switch(config-if)#
Related Commands
cdp (Optional) Enables tunneling of CDP.
stp (Optional) Enables tunneling of STP.
vtp (Optional) Enables tunneling of VTP.
Command Description
l2protocol-tunnel cos Configures the class of service (CoS) value for all tunneled
Layer 2 protocol packet s.
l2protocol-tunnel drop-threshold Sets a drop threshold for the maximum rate of Layer 2
protocol packets per second t o be received before an
interface drops packets.
l2protocol-tunnel shutdown-threshold C onfigures the protocol tunneling encapsulation rate.