Specifications

CHAPTER

14-1

Cisco 7600 Series Router Cisco IOS Software Configuration Guide—12.1E

78-14064-04

Configuring IEEE 802.1Q Tunneling and Layer 2

Protocol Tunneling

With Release 12.1(13)E and later, the Cisco 7600 series routers support IEEE 802.1Q tunneling and

Layer 2 protocol tunneling. This chapter describes how to configure IEEE 802.1Q tunneling and Layer

2 protocol tunneling on the Cisco 7600 series routers.

Note • For complete syntax and usage information for the commands used in this chapter, refer to the

Cisco 7600 Series Router Cisco IOS Command Reference publication.

• The WS-X6548-GE-TX, WS-X6548V-GE-TX, WS-X6148-GE-TX, and WS-X6148V-GE-TX

switching modules do not support IEEE 802.1Q tunneling or Layer 2 protocol tunneling.

This chapter consists of these sections:

• Understanding How 802.1Q Tunneling Works, page 14-1

• 802.1Q Tunneling Configuration Guidelines and Restrictions, page 14-3

• Configuring 802.1Q Tunneling, page 14-5

• Understanding How Layer 2 Protocol Tunneling Works, page 14-7

• Configuring Support for Layer 2 Protocol Tunneling, page 14-8

Understanding How 802.1Q Tunneling Works

802.1Q tunneling enables service providers to use a single VLAN to support customers who have

multiple VLANs, while preserving customer VLAN IDs and keeping traffic in different customer

VLANs segregated.

A port configured to support 802.1Q tunneling is called a tunnel port. When you configure tunneling,

you assign a tunnel port to a VLAN that you dedicate to tunneling. To keep customer traffic segregated,

each customer requires a separate VLAN, but that one VLAN supports all of the customer’s VLANs.

With 802.1Q tunneling, tagged customer traffic comes from an 802.1Q trunk port on a customer device

and enters the service-provider edge router through a tunnel port. The link between the 802.1Q trunk

port on a customer device and the tunnel port is called an asymmetrical link because one end is

configured as an 802.1Q trunk port and the other end is configured as a tunnel port. You assign the tunnel

port to an access VLAN ID unique to each customer. See Figure 14-1 on page 14-2 and Figure 14-2 on

page 14-2.