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CCNA Semester 3

Chapter 07Chap

ter 07

VIRTUAL LANsVIRTUAL LANs

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ObjectivesObjectives

Explain the concept of VLANs.

Configure static VLANs on 29xx seriesCatalyst switchs.

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Table of ContentTable of Content

1 VLAN concepts2 Trunking

3 VLAN configuration

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VLAN CONCEPTSVLAN CONCEPTS

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VLAN introductionVLAN introduction

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Broadcast domains with VLANs and routersBroadcast domains with VLANs and routers

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VLAN typesVLAN types

Port-based VLANs

MAC address based VLANs

Protocol based VLANs

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Port-based VLANsPort-based VLANs

Most common configuration method.

Ports assigned individually.

Often implement when DHCP is used.

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MAC address base VLANsMAC address base VLANs

Rarely implemented today. Each address must be entered into the switch

and configured individually.

Difficult to administer, troubleshoot andmanage.

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Protocol base VLANsProtocol base VLANs

Configured like MAC addresses, but insteaduses a protocol or IP address.

No longer comon because of DHCP.

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Benefits of VLANsBenefits of VLANs

Easily move workstations on the LAN.

Easily add workstations to the LAN.

Easily change the LAN configuration.

Easily control network traffic.

Improve security.

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TRUNKINGTRUNKING

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History of trunkingHistory of trunking

A trunk is a single communications line that

carries multiple channels of signals.

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Trunking conceptTrunking concept

VLAN1

VLAN2

VLAN1

VLAN2

VLAN1

VLAN2

VLAN1

VLAN2

VLAN1

VLAN2

VLAN1 and VLAN2

TRUNK

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VLANs and trunkingVLANs and trunking

ISL

802.1Q

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VLAN Operation on the Trunk

Each logical VLAN is like a separate physical bridge. VLANs can span across multiple switches.

Trunks carry traffic for multiple VLANs.

Trunks use special encapsulation to distinguish between

different VLANs.

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802.1Q Trunking Limitations802.1Q Trunking Limitations

Make sure the native

VLAN for an 802.1Q

trunk is the same onboth ends of the trunk

link.

Make sure your

network is loop-free

before disabling STP.

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Importance of Native VLANsImportance of Native VLANs

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Per-VLAN Spanning TreePer-VLAN Spanning Tree

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Frames TaggingFrames Tagging

ISL

802.1Q

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802.1Q Frame802.1Q Frame

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Performed with ASIC

Not intrusive to client

stations; ISL header notseen by client

Effective between switches,and between routers andswitches

ISL trunks enable VLANs across a backbone.

ISL TaggingISL Tagging

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ISL EncapsulationISL Encapsulation

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VLAN CONFIGURATIONVLAN CONFIGURATION

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VLAN Configuration Guidelines

Maximum number of VLANs is switch-dependent.

Catalyst desktop switches support 64 VLANs witha separate spanning tree per VLAN.

VLAN1 is the factory default Ethernet VLAN.

CDP and VTP advertisements are sent on VLAN1.

The Catalyst switch IP address is in the

management VLAN (VLAN1 by default). To add or delete VLANs, the switch must be in

VTP server or transparent mode.

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End-to-end VLANs and Geographic VLANsEnd-to-end VLANs and Geographic VLANs

End-to-end VLANs:

devices to be grouped based upon resourceusage.

Allow 80/20 rule.

Geographic VLANs:

Devices to be grouped based on geographic.

Allow 20/80 rule.

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Configuring static VLANsConfiguring static VLANs

Create VLANs

Assign ports to VLANs

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wg_sw_1900(config)#vlan vlan# [name vlan-name]

Adding a VLANAdding a VLAN

wg_sw_1900#configure terminalEnter configuration commands, one per line. End with CNTL/Zwg_sw_1900(config)#vlan 9 name switchlab2

Catalyst 1900

Catalyst 2950

wg_sw_2950#vlan database

wg_sw_2950(vlan)#vlan vlan# [name vlan-name]

wg_sw_2950#vlan databasewg_sw_ 2950(vlan)#vlan 9 name switchlab2wg_sw_ 2950(vlan)#exit

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wg_sw_a(config)#vlan vlan# name vlan-name

wg_sw_a#configure terminalEnter configuration commands, one per line. End with CNTL/Zwg_sw_a(config)#vlan 9 name switchlab90

wg_sw_a#show vlan 9

VLAN Name Status Ports------------------------------------------------9 switchlab90 Enabled------------------------------------------------

Modifying a VLAN NameModifying a VLAN Name

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wg_sw_1900(config-if)#vlan-membership {static {vlan#} | dynamic}

Assigning Switch Ports to a VLANAssigning Switch Ports to a VLAN

wg_sw_1900#conf terminalEnter configuration commands, one per line. End with CNTL/Zwg_sw_1900(config)#interface ethernet 0/8wg_sw_1900(config-if)#vlan-membership static 9

Catalyst 1900

Catalyst 2950

wg_sw_2950(config-if)#switchport access vlan vlan#

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Trunking implementationTrunking implementation

Switch# show port capabilities

Switch # configure terminal

Switch(config)# interface f0/1

Switch (config-if)# Switchport mode trunk

Switch(config-if)# Switchport trunkencapsulation dot1q/isl

Switch# Show trunk

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wg_sw_1900#conf terminalEnter configuration commands, one per line. End with CNTL/Zwg_sw_1900(config)#interface f0/26wg_sw_1900(config-if)#trunk on

First Trunk Port (Port A)

wg_sw_1900(config-if)#trunk [on | off | desirable | auto |nonegotiate]

on = Set trunk on and negotiate with other side

off = Set trunk off and negotiate with other side

desirable = Negotiate with other side;

trunk on if other side is on, desirable, or auto

auto = Will be a trunk only if the other side is on or desirable

nonnegotiate = Set trunk on and will not negotiate

Configuring Trunking on Catalyst 1900Configuring Trunking on Catalyst 1900

Note: The Catalyst 1900 only supports ISL encapsulation.

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wg_sw_1900#show trunk aDISL state: On, Trunking: On, Encapsulation type: ISL

wg_sw_1900#show trunk [A | B]

Verifying a TrunkVerifying a Trunk

Catalyst 1900

Catalyst 2950

wg_sw_2950#show interface interface switchport

wg_sw_2950#show interface fa0/2 switchportName: Fa0/2Switchport: EnabledAdministrative mode: trunkOperational Mode: trunk. . .

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wg_sw_1900#show vlan 9

VLAN Name Status Ports-------------------------------------------------9 switchlab2 Enabled-------------------------------------------------

VLAN Type SAID MTU Parent RingNo BridgeNo Stp Trans1 Trans2---------------------------------------------------------------------------9 Ethernet 100009 1500 0 1 1 Unkn 0 0

---------------------------------------------------------------------------

wg_sw_1900#show vlan [vlan#]

Verifying a VLANVerifying a VLAN

Catalyst 1900

Catalyst 2950

wg_sw_2950#show vlan [idvlan#]

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wg_sw_1900#show vlan-membership

Port VLAN Membership Type Port VLAN Membership Type--------------------------- ------------------------------1 5 Static 13 1 Static2 1 Static 14 1 Static3 1 Static 15 1 Static4 1 Static 16 1 Static5 1 Static 17 1 Static

6 1 Static 18 1 Static7 1 Static 19 1 Static8 9 Static 20 1 Static

Note: port 1=e0/1, port 2=e0/2 .....

wg_sw_1900#show vlan-membership

Verifying VLAN Membership on a Catalyst 1900Verifying VLAN Membership on a Catalyst 1900

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wg_sw_2950#show vlan brief VLAN Name Status Ports---- ------------------------ --------- -----------------------1 default active Fa0/4, Fa0/5, Fa0/6, Fa0/7,

Fa0/8, Fa0/9, Fa0/10, Fa0/11,Fa0/12, Fa0/13, Fa0/14, Fa0/15,Fa0/16, Fa0/17, Fa0/18, Fa0/19,Fa0/20, Fa0/21

5 VLAN5 active Fa0/39 VLAN9 active Fa0/22, Fa0/231002 fddi-default active1003 token-ring-default active

1004 fddinet-default active1005 trnet-default active

wg_sw_2950#show vlan brief

Verifying VLAN Membership on a Catalyst 2950Verifying VLAN Membership on a Catalyst 2950

wg_sw_2950#show interfaces interface switchport

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wg_sw_1900#show spantree 1

VLAN1 is executing the IEEE compatible Spanning Tree ProtocolBridge Identifier has priority 32768, address 0050.F037.DA00Configured hello time 2, max age 20, forward delay 15Current root has priority 0, address 00D0.588F.B600

Root port is FastEthernet 0/26, cost of root path is 10Topology change flag not set, detected flag not setTopology changes 53, last topology change occurred 0d00h17m14s agoTimes: hold 1, topology change 8960

hello 2, max age 20, forward delay 15Timers: hello 2, topology change 35, notification 2

Port Ethernet 0/1 of VLAN1 is ForwardingPort path cost 100, Port priority 128Designated root has priority 0, address 00D0.588F.B600Designated bridge has priority 32768, address 0050.F037.DA00Designated port is Ethernet 0/1, path cost 10Timers: message age 20, forward delay 15, hold 1

wg_sw_1900#show spantree [vlan#

]

Verifying STP for a VLANVerifying STP for a VLAN

Catalyst 1900

Catalyst 2950 wg_sw_2950#show spanning-tree vlan [vlan#]

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SummarySummary

Definition of VLANs

Trunking

Configuring static VLANs on Catalyst switches

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Q&AQ&A