Cisco Systems 8540 Configuring 802.1Q Vlan Encapsulation, Routerconfig# bridge 2 protocol ieee

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Chapter 4 Configuring Interfaces

Configuring 802.1Q VLAN Encapsulation

Example

The following example shows how to configure the interfaces for VLAN bridging with ISL encapsulation shown in Figure 4-2:

Router(config)# interface fastethernet 1/0/1.1

Router(config-subif)# encap isl 50

Router(config-subif)# bridge-group 1

Router(config-subif)#interface fastethernet 1/0/0

Router(config-if)# bridge-group 1

Router(config-if)# exit

Router(config)# bridge 1 protocol ieee

Router(config)# interface fastethernet 1/0/1.2

Router(config-subif)# encap isl 100

Router(config-subif)# bridge-group 2

Router(config-subif)#interface fastethernet 3/0/1

Router(config-subif)# bridge-group 2

Router(config-subif)# exit

Router(config)# bridge 2 protocol ieee

Router(config)# exit

Router# copy system:running-config nvram:startup-config

When configuring ISL with IP, you cannot configure IP addresses on a subinterface unless the VLANs are already configured (that is, you must have already entered the encapsulation isl or encapsulation dot1q command). That is not the case with IPX, however—you can configure IPX networks on a subinterface even when the VLANs have not been configured.

The maximum VLAN bridge group values are as follows:

•Maximum number of bridge groups: 64

•Maximum number of interfaces per bridge group: 128

•Maximum number of subinterfaces per system: 255

For a complete configuration example for VLANs with ISL encapsulation, see the “Catalyst 8540 CSR with ISL, VLAN, and BVI with GEC” section on page C-1.

To monitor the VLANs once they are configured, use the commands described in the “Monitoring VLAN Operation” section on page 4-12.

Configuring 802.1Q VLAN Encapsulation

The IEEE 802.1Q standard provides a method for secure bridging of data across a shared backbone. IEEE 802.1Q VLAN encapsulation uses an internal, or one level, packet tagging scheme to multiplex VLANs across a single physical link, while maintaining strict adherence to the individual VLAN domains.

On an IEEE 802.1Q trunk port, all transmitted and received frames are tagged except for those on the one VLAN configured as the PVID (port VLAN identifier) or native VLAN for the port. Frames on the native VLAN are always transmitted untagged and are normally received untagged.

The VLAN configuration example shown in Figure 4-3depicts the following:

•Fast Ethernet ports 1/0/0 and subinterface 1/0/1.1 on the switch router are in bridge group 1. They are part of native VLAN 1, which uses 802.1Q encapsulation.

•Fast Ethernet port 3/0/1 and subinterface 1/0/1.2 are in bridge group 2. They are part of VLAN 100, which uses 802.1Q encapsulation.

•Fast Ethernet port 1/0/1 is configured as an 802.1Q trunk.

 

Layer 3 Switching Software Feature and Configuration Guide

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

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Contents Configuring Interfaces Media Access Control Address Overview of Interface ConfigurationInterface Port Identifier Router# configure terminal General Instructions for Configuring InterfacesRouterconfig# interface gigabitethernet 1/0/1 About Layer 3 Switching Interfaces About the Enhanced Gigabit Ethernet Interfaces Catalyst Initially Configuring Gigabit Ethernet InterfacesCommand Purpose ExampleVerifying the Ethernet Interface Configuration Initially Configuring Fast Ethernet InterfacesCommand Description Router# show interface gigabitethernet 0/0/0 ExamplesRouter# show interface fastethernet 1/0/0 Configuring ISL Vlan Encapsulation About Virtual LANsConfigure the Fast Ethernet main interface Routerconfig-if# Enters subinterface configuration modeRouterconfig-subif# Routerconfig# bridge bridge-group protocol ieeeRouterconfig-subif#interface fastethernet 1/0/0 Configuring 802.1Q Vlan EncapsulationRouterconfig# interface fastethernet 1/0/1.1 Routerconfig-subif#interface fastethernet 3/0/1Bridge-group IeeeMonitoring Vlan Operation About Packet over Sonet CatalystAbout the POS OC-12c Uplink Interface POSConfiguring the POS OC-12c Uplink Interface Catalyst Initially Configuring the POS Interface Default ConfigurationParameter Configuration Command Default Value Hdlc ppp Automatic Reverting of Clock SourceIp-address subnet-mask Line internalAdditional Configurations Customizing the ConfigurationSetting the MTU Size Sdh sonet Configuring FramingConfiguring Sonet Overhead Value j0 value sls0 valueScrambling is on by default Configuring POS SPE ScramblingScramble-atm Configuring Sonet Alarms Alarm Configuring Sonet Delay TriggersAlarm Description Slos Verifying the POS ConfigurationLais pais plop prdi slof Triggers line path millisecondRouter# show protocols pos 1/0/0 Router# show controllers pos 2/0/0 LOP = PLM-PRouter# show controller pos 2/0/0 detail Smdr About ATM Uplinks Catalyst About the ATM Uplink InterfaceNo loopback Configuring the ATM Uplink Interface CatalystConfiguration Overview No atm sonet stm-1 for OC-3Atm vc-per-vp Initially Configuring the ATM Uplink InterfaceNo atm clock internal Parameter ValueConfiguring the Clock Source Stm-1 Configuring Sonet FramingRouterconfig-if# atm sonet ATM interface or to STM-4 for the OC-12c interfaceSls0 is part of the payload pointer byte Overhead c2 byte j0 bytesMsg line j1 16byte exp-msg Line msg line 64byte exp-msgConfiguring Loopback Configuring the Maximum VCs per VP Configuring Virtual CircuitsConfiguring CDP Creating a PVCIp-address atm-vc vcd Mapping a Protocol Address to a PVCVpi vci aal-encap NameSwitch Router a Verifying the ATM ConfigurationSwitch Router B 5CB Configuring Interfaces About Port Snooping About Port SnoopingAbout the Snooping Destination Port Configuring SnoopingRestrictions on Port Snooping About the Snooping Source PortDirection receive transmit both Source-portDestination-port Monitoring SnoopingShow snoop interface Show snoop78-6235-04, Cisco IOS Release 12.010W518
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