Cisco 3845 - Security Bundle Router Software Manual page 249

Chapter 11 Configuring Ethernet Virtual Connections (EVCs)
Figure 11-4
In a service-provider network, you can use Layer 2 protocol tunneling to enhance the creation of
EtherChannels by emulating a point-to-point network topology. When you enable protocol tunneling
(PAgP or LACP) on the service-provider switch, remote customer switches receive the PDUs and can
negotiate the automatic creation of EtherChannels.
For example, in
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 11-5
Customer A
Site 1
Use the l2protocol tunnel protocol service-instance configuration command to enable Layer 2 protocol
tunneling on a service instance:
Valid protocols include CDP, DTP, LACP, LLDP, PAgP, STP, VTP, and UDLD. 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:
Switch (config)# interface gigabitethernet0/2
Switch (config)# switchport mode trunk
Switch (config)# switchport trunk allowed vlan none
Switch (config-if)# service instance 10 Ethernet
Switch (config-if-srv)# encapsulation untagged, dot1q 200 second-dot1q 300
OL-23400-01
Layer 2 Network Topology without Proper Convergence
Customer X
virtual network
VLANs 1 to 100
Figure 11-5, Customer A has two switches in the same VLAN that are connected
Layer 2 Protocol Tunneling for EtherChannels
EtherChannel 1
VLAN 17
VLAN 18
VLAN 19
VLAN 20
Service
Provider
Switch A Switch C
Switch B Switch D
Cisco ME 3800X and 3600X Switch Software Configuration Guide
Configuring Other Features on EFPs
EtherChannel 1
VLAN 17
Customer A
VLAN 18
VLAN 19
VLAN 20
Trunk
Asymmetric link
Site 2
11-23