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Cisco ME 3800X and 3600X Switch Software Configuration Guide
OL-23400-01
Chapter 11 Configuring Ethernet Virtual Connections (EVCs)
Configuring Other Features on EFPs
For Customer A, service instance 1 on Gigabit Ethernet port 0/1 is configured with the VLAN
encapsulations used by the customer: C-VLANs 1–100. These are forwarded on bridge-domain 5000.
The service provider facing port is configured with a service instance on the same bridge-domain and
with an encapsulation dot1q command matching the S-VLAN. The rewrite ingress pop 1 symmetric
command also implies a push of the configured encapsulation on egress packets. Therefore, the original
packets with VLAN tags between 1 and 100 are encapsulated with another S-VLAN (VLAN 30) tag
when exiting Gigabit Ethernet port 0/2.
Similarly, for double- tagged (S-VLAN = 30, C-VLAN = 1–100) packets coming from the provider
network, the rewrite ingress pop 1 symmetric command causes the outer S-VLAN tag to be popped
and the original C-VLAN tagged frame to be forwarded over bridge-domain 5000 out to Gigabit Ethernet
port 0/1.
The same scenario applies to Customer B.
Customer B
Switch (config)#
interface gigabitethernet0/3
Switch (config-if)#
service instance 1 Ethernet
Switch (config-if-srv)#
encapsulation dot1q 1-200
Switch (config-if-srv)#
bridge-domain 5000
Switch (config)#
interface gigabitethernet0/4
Switch (config-if)#
service instance 2 Ethernet
Switch (config-if-srv)#
encapsulation dot1q 40
Switch (config-if-srv)#
rewrite ingress pop 1 symmetric
Switch (config-if-srv)#
bridge-domain 5000
Method 2
QinQ is also supported when sending packets between an EFP and a switchport trunk, because the
switchport trunk is implicitly defined as rewrite ingress pop 1 symmetric. The same external behavior as
Method 1 can be achieved with this configuration:
Customer A
Switch (config)#
interface gigabitethernet0/1
Switch (config-if)#
service instance 1 Ethernet
Switch (config-if-srv)#
encapsulation dot1q 1-100
Switch (config-if-srv)#
bridge-domain 30
Switch (config)#
interface gigabitethernet0/2
Switch (config-if)#
switchport mode trunk
Again, service instance 1 on Gigabit Ethernet port 0/1 is configured with the VLAN encapsulations used
by the customer: C-VLANs 1–100. These are forwarded on bridge-domain 30. The service provider
facing port is configured as a trunk port. The trunk port implicitly pushes a tag matching the
bridge-domain that the packet is forwarded on (in this case S-VLAN 30).
Note
The bridge-domain used must be allowed on the trunk port. This means it must be in the range 1 to 4094
and must be allowed on that trunk port (switchport trunk allowed vlan must include 30).
For double tagged (S-VLAN = 30, C-VLAN = 1 to 100) packets coming in from the provider network,
the trunk port implicitly pops the outer S-VLAN (30) and forwards the packet on that bridge-domain.
