Sybex CCNA 640-802 Chapter 11

8/11/2019 Sybex CCNA 640-802 Chapter 11

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Sybex CCNA 640-802Chapter 11: VLANs Instructor & Todd Lammle


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Chapter 11 Objectives

The CCNA Topics Covered in this chapterinclude:

What is a VLAN? VLAN Memberships VLAN links Frame tagging VTP, RSTP,PVSTP, 802.1q Trunking Configuring VLANs Inter-VLAN Communication Configuration examples

2


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Virtual LANs (VLANs)

Definition: A logical grouping ofnetwork users and resourcesconnected to administratively defined

ports on a switch. Smaller broadcast domains Organized by:

Location Function Department Application or protocol


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Switches


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Features of VLANs

Simplify network management Provides a level of security over

a flat network Flexibility and Scalability


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Broadcast Control

Broadcasts occur in everyprotocol

Bandwidth & Broadcasts

Flat network

VLANs & Broadcasts


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Flat Network Structure


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Switched Network


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Security

Flat network problems

VLANs


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Flexibility & Scalability Layer-2 switches only read frames

Can cause a switch to forward allbroadcasts

VLANs Essentially create broadcastdomains

Greatly reduces broadcast traffic

Ability to add wanted users to a VLANregardless of their physical location Additional VLANs can be created when

network growth consumes morebandwidth


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Physical LANs Connected To A Router


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VLANs Remove The PhysicalBoundary


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VLAN Memberships

Static VLANs Typical method of creating VLANs Most secure

A switch port assigned to a VLAN always

maintains that assignment until changed Dynamic VLANs

Node assignment to a VLAN is automatic MAC addresses, protocols, network addresses,

etc VLAN Management Policy Server (VMPS)

MAC address database for dynamic assignments MAC-address to VLAN mapping


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Identifying VLANs

Access links A link that is part of only one VLAN

Trunk links Carries multiple VLANs


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Identifying VLANs (cont.)


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Frame Tagging

Definition: A means of keepingtrack of users & frames as theytravel the switch fabric & VLANs

User-defined ID assigned to eachframe

VLAN ID is removed before

exiting trunked links & accesslinks


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VLAN ID Methods

Inter-Switch Link (ISL) Cisco proprietary

FastEthernet & Gibabit Ethernetonly IEEE 802.1q

Must use if trunking between Cisco& non-Cisco switch


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Inter-Switch Link (ISL)Protocol

Definition: A means of explicitlytagging VLAN information ontoan Ethernet frame

Allows VLANs to be multiplexedover a trunk line

Cisco proprietary External tagging process


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VLAN Trunk Protocol (VTP)

Purpose: to manage allconfigured VLANs across aswitch internetwork & maintainconsistency

Allows an administrator to add,delete, & rename VLANs


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VTP Benefits

Benefits Consistent configuration Permits trunking over mixed

networks Accurate tracking Dynamic reporting Plug-and-Play

A VTP server must be created tomanage VLANs


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VTP Modes


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VTP Modes of Operation

Server Default for all Catalyst switches Minimum one server for a VTP domain

Client Receives information + sends/receives

updates Cannot make any changes

Transparent Does not participate in a VTP domain

but forwards VTP advertisements Can add/delete VLANs Locally significant


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Router with Individual VLANassociations


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Routing Between VLANs


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Configuring VLANs

Creating VLANs Assigning Switch Ports to

VLANs Configuring Trunk Ports Configuring Inter-VLAN

routing


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Creating VLANs

S1#config tS1(config)#vlan ?

WORD ISL VLAN IDs 1-4094internal internal VLAN

S1(config)#vlan 2

S1(config-vlan)#name SalesS1(config-vlan)#vlan 3S1(config-vlan)#name MarketingS1(config-vlan)#vlan 4S1(config-vlan)#name Accounting

i i S i h


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Assigning Switch Ports toVLANs

S1#config tS1(config)#int fa0/3S1(config-if)#switchport mode accessS1(config-if)#switchport access vlan 3


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Configuring Trunk Ports2960 (802.1q)S1#config t

S1(config)#int fa0/8S1(config-if)#switchport mode trunk

3560 (ISL or IEEE 802.1Q)Core(config-if)#switchport trunk encapsulation?

dot1q Interface uses only 802.1qtrunking encapsulation when trunkingisl Interface uses only ISL trunking

encapsulation when trunkingnegotiate Device will negotiatetrunking encapsulation with peer oninterface

Core(config-if)#switchport trunk encapsulationdot1qCore(config-if)#switchport mode trunk

C fi i I VLAN


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Configuring Inter-VLANrouting

Router(config)# interface fastethernet 0Router(config-if)# no ip addressRouter(config)# interface fastethernet 0/1.1Router(config-if)# encapsulation dot1q 1Router(config-if)# ip address 192.168.1.1 255.255.255.0Router(config-if)# interface fastethernet 0/1.10Router(config-if)# encapsulation dot1q 10Router(config-if)# ip address 192.168.2.1 255.255.255.0


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Configuring VTP

Switches are configured to beVTP servers by default.


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InterVLAN ConfigurationExample


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Example 2


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Example 3


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Example 4


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Configuring VTP

Switches are configured to beVTP servers by default.


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Configuring Switching ASample Internetwork


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2950C


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2950B


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Setting Up Trunking


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Inter-VLAN communication


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Telephony: Configuring VoiceVLANs

The voice VLAN feature enables access ports to carry IPvoice traffic from an IP phone

You can configure access ports on the switch to send CiscoDiscovery Protocol (CDP) packets that instruct an attachedCisco IP phone to send voice traffic to the switch inany of these ways:

In the voice VLAN tagged with a layer 2 CoS priority value In the access VLAN tagged with a layer 2 CoS priority

value

In the access VLAN, untagged (no layer 2 CoS priorityvalue)


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Configuring the Voice VLAN

Switch#configure tSwitch(config)#mls qosSwitch(config)#interface f0/1Switch(config-if)#switchport priority extend ?

cos Override 802.1p priority of devices on appliance

trust Trust 802.1p priorities of devices on applianceSwitch(config-if)#switchport priority extend trustSwitch(config-if)#mls qos trust cosSwitch(config-if)#switchport voice vlan dot1pSwitch(config-if)#switchport mode accessSwitch(config-if)#switchport access vlan 3Switch(config-if)#switchport voice vlan 1 0


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Written Labs and ReviewQuestions

Open your books and go through all thewritten labs and the review questions.

Review the answers in class.

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Sybex CCNA 640-802 Chapter 11