Cisco Systems A9014CFD manual Configuration Examples of Unsupported Features, Example Filtering

Chapter 8 Configuring Ethernet Virtual Connections

Configuration Examples of Unsupported Features

Configuration Examples of Unsupported Features

•Example: Filtering

•Example: Overlapping Encapsulation

Example: Filtering

In EVC switching, egress filtering is performed before the frame is sent on the egress EFP. Egress filtering ensures that when a frame is sent, it conforms to the matching criteria of the service instance applied on the ingress direction. EFP does not require egress filtering if the number of pops is the same as the number of VLANs specified in the encapsulation command.

Note Specifying the cos keyword in the encapsulation command is relevant only in the ingress direction. For egress filtering, cos is ignored.

Router (config)# interface gigabitethernet0/1

Router (config-if)#service instance 1 Ethernet

Router (config-if-srv)# encapsulation dot1q 20

Router (config-if-srv)# bridge-domain 19

Router (config)# interface gigabitethernet0/2

Router (config-if)#service instance 2 Ethernet

Router (config-if-srv)# encapsulation dot1q 30

Router (config-if-srv)# bridge-domain 19

Router (config)# interface gigabitethernet0/3

Router (config-if)#service instance 3 Ethernet

Router (config-if-srv)#encapsulation dot1q 10 second-dot1q 20

Router (config-if-srv)#rewrite ingress pop 1 symmetric

Router (config-if-srv)# bridge-domain 19

If a packet with VLAN tag 10 or 20 is received on Gigabit Ethernet 0/3, the ingress logical port would be service instance 3. For the frame to be forwarded on a service instance, the egress frame must match the encapsulation defined on that service instance after the rewrite is done. Service instance 1 checks for outermost VLAN 20; service instance 2 checks for VLAN 30. In this example, the frame with VLAN tags 10 and 20 can be sent to service instance 1 but not to service instance 2.

Example: Overlapping Encapsulation

The router does not allow overlapping encapsulation. Overlapping encapsulation configuration occurs when two EFPs are configured on the same port and the same bridge domain and the set of encapsulations on one EFP is a subset of the encapsulations on the other EFP.

Service instance 2 configuration is rejected because service instance 1 encapsulation dot1q any is superset of service instance 2 encapsulation dot1q 10.

Router (config)# interface gigabitethernet 0/1

Router (config-if)#service instance 1 ethernet

Router (config-if-srv)# encapsulation dot1q any

Router (config-if-srv)# bridge-domain 10

Router (config-if-srv)# exit

Router (config-if)#service instance 2 ethernet

Router (config-if-srv)# encapsulation dot1q 10

Router (config-if-srv)# bridge-domain 10

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
8-12	OL-23826-09