11-23
Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 11 Configuring Ethernet Virtual Connections (EVCs)
Configuring Other Features on EFPs
Figure 11-4
Layer 2 Network Topology without Proper Convergence
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
Figure 11-5
, 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 11-5
Layer 2 Protocol Tunneling for EtherChannels
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
101821
Customer X
virtual network
VLANs 1 to 100
Switch A
VLAN 17
VLAN 18
VLAN 19
VLAN 20
VLAN 17
VLAN 18
VLAN 19
VLAN 20
Switch B
Switch C
Service
Provider
EtherChannel 1
Customer A
Site 1
Customer A
Site 2
101844
Switch D
EtherChannel 1
Trunk
Asymmetric link