Cisco Systems ONS 15310-CL, ONS 15310-MA Understanding Layer 2 Protocol Tunneling, No ip address

Chapter 9 Configuring IEEE 802.1Q Tunneling and Layer 2 Protocol Tunneling on the ML-Series Card

Understanding Layer 2 Protocol Tunneling

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no ip route-cache mode dot1q-tunnel bridge-group 10

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interface POS0.1 encapsulation dot1Q 10 no ip route-cache bridge-group 10

Understanding Layer 2 Protocol Tunneling

Customers at different sites connected across a service-provider network need to run various Layer 2 protocols to scale their topology to include all remote sites, as well as the local sites. Spanning Tree Protocol (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 infrastructure. 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.

When protocol tunneling is enabled, edge switches on the inbound side of the service-provider infrastructure encapsulate Layer 2 protocol packets with a special MAC address and send them across the service-provider network. Core switches in the network do not process these packets, but forward them as normal packets. CDP, STP, or VTP Layer 2 protocol data units (PDUs) cross the service-provider infrastructure 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 the following results:

•Users on each of a customer’s sites are able to 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 through the service provider to all switches.

Layer 2 protocol tunneling can be used independently or to enhance IEEE 802.1Q tunneling. If protocol tunneling is not enabled on IEEE 802.1Q tunneling ports or on specific VLANs, remote switches at the receiving end of the service-provider network do not receive the PDUs and cannot properly run STP, CDP, and VTP. When protocol tunneling is enabled, Layer 2 protocols within each customer’s network are totally separate from those running within the service-provider network. Customer switches on different sites that send traffic through the service-provider network with IEEE 802.1Q tunneling achieve complete knowledge of the customer’s VLAN. If IEEE 802.1Q tunneling is not used, you can still enable Layer 2 protocol tunneling by connecting to the customer switch through access ports and enabling tunneling on the service-provider access port.

Configuring Layer 2 Protocol Tunneling

Layer 2 protocol tunneling (by protocol) is enabled on the tunnel ports or on specific tunnel VLANs that are connected to the customer by the edge switches of the service-provider network. ML-Series card tunnel ports are connected to customer IEEE 802.1Q trunk ports. The ML-Series card supports Layer 2

Cisco ONS 15310-CL, ONS 15310-MA, and ONS 15310-MA SDH Ethernet Card Software Feature and Configuration Guide, R9.1 and R9.2

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