27
Layer 2 Protocol Tunneling
27.1 Overview
This chapter shows you how to configure layer 2 protocol tunneling on the Switch.
Layer 2 protocol tunneling (L2PT) is used on the service provider's edge devices.
27.1.1 What You Can Do
Use the Layer 2 Protocol Tunnel screen (Section 27.2 on page 253) 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.
27.1.2 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 134 Layer 2 Protocol Tunneling Network Scenario
A |
| Service Provider's | C | ||
STP |
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| Network |
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CDP | 1 |
| STP | 2 | |
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| CDP |
VTP | VTP |
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B
| 251 |
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