Example For Egress Classification Based On Cos; Layer 2 Protocol Tunneling - Cisco ASR 920 Series Configuration Manual Ethernet Router

Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling Using EFPs

Example for Egress Classification Based on CoS

interface GigabitEthernet0/1
service instance 1 ethernet
encapsulation untagged
rewrite ingress tag push dot1q 10
service-policy input set-cos
bridge-domain 20
interface GigabitEthernet0/3
service instance 1 ethernet
encapsulation dot1q 30
service-policy output policy-dscp
bridge-domain 20

Layer 2 Protocol Tunneling

Customers at different sites connected across a service-provider network need to use various Layer 2 protocols
to scale their topologies to include all remote sites, as well as the local sites. STP must run properly, and every
VLAN should build a proper spanning tree that includes the local site and all remote sites across the
service-provider network. Cisco Discovery Protocol (CDP) must discover neighboring Cisco devices from
local and remote sites.
VLAN Trunking Protocol (VTP) must provide consistent VLAN configuration throughout all sites in the
customer network that are participating in VTP. Similarly, DTP, LACP, LLDP, PAgP, and UDLD can also
run across the service-provider network.
When protocol tunneling is enabled, edge switches on the inbound side of the service-provider network
encapsulate Layer 2 protocol packets with a special MAC address (0100.0CCD.CDD0) and send them across
the service-provider network. Core switches in the network do not process these packets but forward them as
normal (unknown multicast data) packets. Layer 2 protocol data units (PDUs) for the configured protocols
cross the service-provider network and are delivered to customer switches on the outbound side of the
service-provider network. Identical packets are received by all customer ports on the same VLANs with these
results:
• Users on each of a customer's sites can properly run STP, and every VLAN can build a correct spanning
tree based on parameters from all sites and not just from the local site.
• CDP discovers and shows information about the other Cisco devices connected through the
service-provider network.
• VTP provides consistent VLAN configuration throughout the customer network, propagating to all
switches through the service provider that support VTP.
Customers use Layer 2 protocol tunneling to tunnel BPDUs through a service-provider network without
interfering with internal provider network BPDUs.
Note Layer 2 protocol tunneling is supported on EFPs, but not on switchports. Layer 2 protocol tunneling is
not supported on cross-connect EFPs.
Carrier Ethernet Configuration Guide (Cisco ASR 920 Series)
34
-> Input interface with EVC Push and EVC policy
Ethernet Virtual Connections Configuration