ZyXEL Communications XGS4600 Series - Layer 2 Protocol Tunneling; Layer 2 Protocol Tunneling Overview; What You Can Do; What You Need to Know

Chapter 32 Layer 2 Protocol Tunneling
XGS4600 Series User’s Guide
338
CHAPTER 32
Layer 2 Protocol Tunneling
32.1 Layer 2 Protocol Tunneling Overview
This chapter shows you how to configure layer 2 protocol tunneling on the Switch.
32.1.1 What You Can Do
Use the Layer 2 Protocol Tunnel screen (Section 32.1 on page 338) to enable layer 2 protocol tunneling
on the Switch and specify a MAC address with which the Switch uses to encapsulate the layer 2
protocol packets by replacing the destination MAC address in the packets.
32.1.2 What You Need to Know
Layer 2 protocol tunneling (L2PT) is used on the service provider's edge devices.
L2PT allows edge switches (1 and 2 in the following figure) to tunnel layer 2 STP (Spanning Tree Protocol),
CDP (Cisco Discovery Protocol) and VTP (VLAN Trunking Protocol) packets between customer switches
(A, B and C in the following figure) connected through the service provider’s network. The edge switch
encapsulates layer 2 protocol packets with a specific MAC address before sending them across the
service provider’s network to other edge switches.
Figure 267 Layer 2 Protocol Tunneling Network Scenario
In the following example, if you enable L2PT for STP, you can have switches A, B, C and D in the same