Cisco Systems A9014CFD manual 35-3

Chapter 35 Layer 2 Control Protocol Peering, Forwarding, and Tunneling

How to Configure Layer 2 Control Protocol Peering, Forwarding, and Tunneling

•Spanning Tree Protocol (STP)—including Multiservice Transport Platform (MSTP) and Per VLAN Spanning Tree (PVST)

•Virtual Trunking Protocol (VTP)

The ASR 901 router allows to tunnel layer 2 packets between CEs. The Cisco proprietary multicast address (01-00-0c-cd-cd-d0) is used while tunneling the packet over the NNI interfaces.

Figure 35-2depicts Layer 2 Protocol Tunneling. The layer 2 traffic is sent through the S-network, and the S-network switches the traffic from end to end. The Cisco multicast address is added to the frames and sent from UNI to NNI. On the reverse path (NNI to UNI), protocol specific multicast address is attached to the frames and sent to the UNI.

Figure 35-2	Layer 2 Protocol Tunneling
		ASR901		ASR901
CE			PE		CE

1 2 3 2 1

334050

1	CE layer 2 control protocol tunnel	3	Third party PE forwards S-tagged frames and
	(end-to-end).		peers untagged frames.
2	Cisco multicast address is added to the frames	4	—
	and sent from UNI to NNI. On the reverse
	path (NNI to UNI), a protocol specific
	multicast address is attached to the frames and
	sent to UNI.

How to Configure Layer 2 Control Protocol Peering, Forwarding, and Tunneling

This section describes how to configure layer 2 control protocol peering, forwarding and tunneling:

Note The configuration defined for LACP impacts all slow protocols, and is applicable to all the options like peering, forwarding, and tunneling.

•Configuring Layer 2 Peering, page 35-4(Required)

•Configuring Layer 2 Forwarding, page 35-5(Required)

•Configuring Layer 2 Tunneling, page 35-7(Required)

•Verifying Layer 2 Peering, page 35-9(Optional)

•Verifying Layer 2 Forwarding, page 35-9(Optional)

•Verifying Layer 2 Tunneling, page 35-9(Optional)

	Cisco ASR 901 Series Aggregation Services Router Software Configuration Guide
OL-23826-09		35-3