Chapter 4 Configuring Interfaces

Configuring 802.1Q VLAN Encapsulation

Figure 4-3 Example of Bridging Between Native and Non-Native 802.1Q VLANs

Bridge-group 1

1/0/1.1

 

1/0/0

 

 

 

Native VLAN 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

encap dot1q 1 native

 

 

 

 

 

 

 

 

 

 

 

Campus

 

 

 

 

 

 

encap dot1q 100

 

Campus

 

 

 

 

 

 

 

 

 

 

 

 

 

switch

 

 

 

 

 

 

 

 

switch

router

 

 

 

 

 

 

 

 

router

 

 

 

 

 

 

 

 

Non-native VLAN 100

3/0/1 1/0/1.2

Bridge-group 2

28089

To configure the bridging between native VLAN 1 and non-native VLAN 100 depicted in Figure 4-3,perform the following steps:

 

Command

Purpose

 

Step 1

 

 

 

Router(config)# interface fastethernet

Enters subinterface configuration mode.

 

 

slot/subslot/interface.subinterface

 

 

 

 

 

Step 2

 

 

 

Router(config-subif)# encap dot1q vlan-idnative

Specifies 802.1Q encapsulation for Ethernet

 

 

 

frames sent from the subinterface with a header

 

 

 

that maintains the specified native VLAN ID

 

 

 

between network nodes.

 

Step 3

 

 

 

Router(config-subif)# bridge-group

Assigns the subinterface a bridge group number.

 

 

bridge-group

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Note

When you are configuring VLAN

 

 

 

 

 

 

routing, skip this step.

 

Step 4

 

 

 

 

 

 

 

Router(config-subif)# interface fastethernet

Enters interface configuration mode to configure

 

 

slot/subslot/interface

the Fast Ethernet main interface.

 

Step 5

 

 

 

Router(config-if)# bridge-groupbridge-group

Assigns the main interface to the bridge group.

 

Step 6

 

 

 

Router(config-if)# exit

Returns to global configuration mode.

 

Step 7

 

 

 

Router(config)# bridge bridge-groupprotocol

Specifies that the bridge group will use the IEEE

 

 

ieee

Ethernet Spanning Tree Protocol.

 

 

 

 

 

 

 

 

 

 

Layer 3 Switching Software Feature and Configuration Guide

 

 

 

 

 

 

 

78-6235-04, Cisco IOS Release 12.0(10)W5(18)

 

 

4-11

 

 

 

 

 

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Cisco Systems 8510 CSR, 8540 CSR appendix Bridge-group, Ieee