For example, in figure below, Customer A has two switches in the same VLAN that are connected through
the SP network. When the network tunnels PDUs, switches on the far ends of the network can negotiate the
automatic creation of EtherChannels without needing dedicated lines.
Figure 3: Layer 2 Protocol Tunneling for EtherChannels
Use the
l2protocol tunnelprotocol
service-instance configuration command to enable Layer 2 protocol
tunneling on a service instance
Valid protocols include CDP, LACP, LLDP, PAgP, STP, UDLD, and VTP. If a protocol is not specified for
a service instance, the protocol frame is dropped at the interface.
This is an example of Layer 2 protocol tunneling configuration:
Router (config)# interface gigabitethernet0/2
Router (config-if)# service instance 10 Ethernet
Router (config-if-srv)# encapsulation untagged , dot1q 200 second-dot1q 300
Router (config-if-srv)# l2protocol tunnel cdp stp vtp pagp lacp
Router (config-if-srv)# bridge-domain 10
To enable tunneling of most Layer 2 protocol, you must configure
encapsulation untagged
because Layer
2 protocol PDUs are usually untagged.
Note
Layer 2 protocol tunneling statistics
The following command is used to view the Layer 2 protocol tunneling statistics:
show ethernet service instance id service-instance id
interface
interface
platform.
This is an example of Layer 2 protocol tunneling statistics:
2020#sh run int gi0/0/9
Building configuration...
Current configuration : 228 bytes
interface GigabitEthernet0/0/9
no ip address
media-type auto-select
negotiation auto
no keepalive
service instance 200 ethernet
encapsulation untagged
l2protocol tunnel
xconnect 2.2.2.2 1 encapsulation mpls
Carrier Ethernet Configuration Guide (Cisco ASR 920 Series)
37
Ethernet Virtual Connections Configuration
Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling Using EFPs