L2TP Configuration
Chapter 36. L2TP Configuration
36.1 L2TP Overview
L2TP (Layer 2 Tunneling Protocol) is a Layer 2 tunneling technology, L2TP enables Layer
2 protocol packets from geographically dispersed customer networks to be transparently
transmitted over specific tunnels across a service provider network.
Figure 36-1 L2TP application scenario
With L2TP, Layer 2 protocol packets from customer networks can be transparently
transmitted in the service provider network:
1. After receiving a Layer 2 protocol packet from User A network 1, PE 1 in the service
provider network encapsulates the packet, replaces its destination MAC address with a
specific multicast MAC address, and then forwards the packet in the service provider network.
2. The encapsulated Layer 2 protocol packet (called bridge protocol data unit, BPDU for
short) is forwarded to PE 2 at the other end of the service provider network, which
de-encapsulates the packet, restores the original destination MAC address of the packet, and
then sends the packet to User A network 2.
36.2 L2TP Configuration
36.2.1 Configure L2-tunnel Packet
Tqable 36-1 Configure the L2-tunnel packet
Enter global configuration mode
Enter interface configuration mode
interface ethernet interface-num
Configure the L2-tunnel packet
l2-tunnel [cdp| lacp| pagp| stp|
udld|vtp]