ccna exp3 - chapter04 - vtp.ppt [compatibility mode]

8/3/2019 CCNA Exp3 - Chapter04 - VTP.ppt [Compatibility Mode]

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Chapter 4: VTP

CCNA Ex loration 4.0

1


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Overview

http://www.cisco.com/warp/public/473/vtp_flash

Hc vin mng Bach Khoa - Website: www.bkacad.com 2


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VTP Concepts



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The VLAN Management Challenge



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VTP


VTP allows a network manager to makes changes on a switch that isconfigured as a VTP server. Basically, the VTP server distributes and synchronizes VLAN information to

VTP-enabled switches throughout the switched network, which minimizes theproblems caused by incorrect configurations and configuration inconsistencies.

VTP stores VLAN configurations in the VLAN database called vlan.dat.


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VTP

VTP is a La er 2 messa in rotocol that maintains VLAN confi uration


consistency by managing the addition, deletion, and renaming of VLANs on anetwork-wide basis.

VTP minimizes misconfigurations and configuration inconsistencies that cancause several problems, such as duplicate VLAN names, incorrect VLAN-typespecifications, and security violations.

(www.cisco.com) VLAN Trunk Protocol (VTP) reduces administration in aswitched network. When you configure a new VLAN on one VTP server, theVLAN is distributed through all switches in the domain. This reduces the needto configure the same VLAN everywhere. VTP is a Cisco-proprietary protocolthat is available on most of the Cisco Catalyst series products.


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VTP



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Benefits of VTP



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VTP Domain


VTP Domain -Consists of one or more interconnected switches.

All switches in a domain share VLAN configuration details using VTPadvertisements. A router or Layer 3 switch defines the boundary of each domain.


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VTP mode



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VTP mode

VTP Server-VTP servers advertise the VTP domain VLAN informationto other VTP-enabled switches in the same VTP domain. VTP servers store the VLAN information for the entire domain in

NVRAM.

The server is where VLAN can created, deleted, or renamed for thedomain.

VTP Client-VTP clients function the same way as VTP servers, butyou cannot create, change, or delete VLANs on a VTP client.


c en on y s ores e n orma on or e en re oma nwhile the switch is on.

A switch reset deletes the VLAN information. You must configure VTP client mode on a switch.

VTP Transparent-Transparent switches forward VTP advertisementsto VTP clients and VTP servers. Transparent switches do not participate in VTP. VLANs that are created, renamed, or deleted on transparent

switches are local to that switch only.


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Extra: VTP mode

ServerIn VTP server mode, you can create, modify, and deleteVLANs and specify other configuration parameters, such as VTPversion and VTP pruning, for the entire VTP domain. VTP serversadvertise their VLAN configuration to other switches in the same VTP

domain and synchronize their VLAN configuration with other switchesbased on advertisements received over trunk links. VTP server is thedefault mode.

ClientVTP clients behave the same way as VTP servers, but youcannot create, change, or delete VLANs on a VTP client.


TransparentVTP transparent switches do not participate in VTP. AVTP transparent switch does not advertise its VLAN configuration anddoes not synchronize its VLAN configuration based on receivedadvertisements, but transparent switches do forward VTPadvertisements that they receive out their trunk ports in VTP Version 2.

Off (configurable only in CatOS switches)In the three describedmodes, VTP advertisements are received and transmitted as soon asthe switch enters the management domain state. In the VTP off mode,switches behave the same as in VTP transparent mode with theexception that VTP advertisements are not forwarded.


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VTP pruning



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VTP advertisement


VTP Advertisements -VTP uses a hierarchy of advertisements todistribute and synchronize VLAN configurations across the network.


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Test your knowledge



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VTP Operation



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Default VTP configuration



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VTP Version -Displays the VTP version the switch is capable of running. Bydefault, the switch implements version 1, but can be set to version 2.

Configuration Revision -Current configuration revision number on this switch.You will learn more about revisions numbers in this chapter.

Maximum VLANs Supported Locally -Maximum number of VLANs supportedlocally.

Number of Existing VLANs -Number of existing VLANs.

VTP Operating Mode -Can be server, client, or transparent.


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Default hash value


VTP Domain Name -Name that identifies the administrative domain for the switch. VTP Pruning Mode -Displays whether pruning is enabled or disabled. VTP V2 Mode -Displays if VTP version 2 mode is enabled. VTP version 2 is disabled by

default.

VTP Traps Generation -If you enable this feature, it causes an SNMP message to begenerated every time a new VTP message is sent. MD5 Digest -A 16-byte checksum of the VTP configuration.

(The VTP password that you configure is translated by algorithm into a 16-byte word(MD5 value) that is carried in all summary-advertisement VTP packets)

Configuration Last Modified -Date and time of the last configuration modification.

Displays the IP address of the switch that caused the configuration change to thedatabase.


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VTP Domains


VTP allows you to separate your network into smaller management domains tohelp reduce VLAN management.

An additional benefit of configuring VTP domains is that it limits the extent to

which configuration changes are propagated in the network if an error occurs.


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VTP Domain Name Propogation



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VTP Frame Structure


VTP message types:1. Summary advertisements2. Subset advertisement3. Advertisement requests4. VTP join messages


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VTP message content



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VTP Revision Number


The configuration revision number is a 32-bit number that indicates the level of revision for a VTPframe.

The default configuration number for a switch is 0. Each time:

Add or remove a VLAN, assign or change name of vlan Change VTP version Enable or disable prunningthe configuration revision number is incremented.

Each VTP device tracks the VTP configuration revision number that is assigned to it. Note:

A VTP domain name change does not increment the revision number. Instead, it resets therevision number to zero.


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Extra: Reset a Revision Number to Zero

Disable trunkingChange the VTP domain name

Change the new domain name back to the original


nameRe-enable trunking.

OR

switch# delete flash:vlan.datswitch# reload


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VTP Advertisements



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Summary Advertisements

or Client



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Summary Advertisements

The VTP version is either 1 or 2. Code indicates which of the four VTP message types is includedhere, 0x01 or type 1. Followers indicates how man VTP subset advertisement messa es t e 2 follow the


summary advertisement frame. The value can range from 0 to 255; 0 indicates that no

subset advertisements follow. A Catalyst transmits the subset advertisement only if thereis a change in the system or as a response to an advertisement request.

MgmtD Len specifies the length of the VTP domain name. Management Domain Name specifies the VTP domain name. The Configuration Revision Number field is 32 bytes. The Updater Identity is the IP address of the last switch that incremented the

configuration revision. Update Timestamps are the date and time of the last increment of the configuration

revision. MD5 Digest consists of a message-digest hash- a function of the VTP password and the

VTP header contents (excluding the MD5 Digest field). If the receiving Catalyst hashcomputation does not match, the packet is discarded


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Subset Advertisements

Code is 0x02 for subsetadvertisement (type 2).

Seq-Number represents thesequence number of thepacket in the stream ofsubset advertisementsfollowing a summaryadvertisement. The


sequence s ar s w . e

receiving Catalyst uses thisvalue to ensure that itreceives all subsetadvertisements. If it does notreceive all of the subsets, itrequests a resend, starting

with a specific subsetadvertisement.


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Subset Advertisements


VLAN-info fields each contain the following information: The VLANs status (active or suspended)

VLAN-Type (Ethernet, Token Ring, FDDI, or otherwise)

VLAN-Name Len Length of the VLAN name

ISL VLAN-ID VLAN number of this named VLAN

MTU size Maximum frame size supported for this VLAN 802.10 Index SAID value used if the frame passed over an FDDI trunk

VLAN-name

The VTP subset advertisement lists this information for each individual VLAN,including default VLANs.


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Request Advertisements


Code is 0x03 for advertisement request (type 3). The VTP domain name has been changed

The switch receives a summary advertisement with a higherconfiguration revision number than its own

A subset advertisement message is missed for some reason

The switch has been reset


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Action 4.2.4



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VTP Modes Overview



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VTP Mode Comparisions

VTP servers: Create, modify, and delete VLAN and VLAN configuration parameters

for the entire domain.

VTP servers save VLAN configuration information in the switch NVRAM.

VTP servers send VTP messages out to all trunk ports.

VTP clients: Cannot create, modify, or delete VLAN information.


VLAN information. The only role of VTP clients is to process VLAN changes and send VTP

messages out all trunk ports.

VTP transparent mode: Forward VTP advertisements but ignore information contained in the

message. Not modify its database when updates are received

Not send out an update indicating a change in its VLAN status.

Only forwarding VTP advertisements, VTP is disabled on a transparentswitch.


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VTP Pruning


VTP pruning prevents unnecessary flooding of broadcast information from oneVLAN across all trunks in a VTP domain.

VTP pruning permits switches to negotiate which VLANs are assigned to portsat the other end of a trunk and, hence, prune the VLANs that are not assignedto ports on the remote switch.

Pruning is disabled by default. VTP pruning is enabled using the vtp pruningglobal configuration command.

You need to enable pruning on only one VTP server switch in the domain.


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VTP Pruning



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VTP Pruning



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VTP Pruning- Activity 4.2.5.4



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Configure VTP



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VTP Configuration Guidelines



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Topology example


C fi D il


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Confirm Detail


C fi D i N


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Configure Domain Name


C fi V i


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Configure Version


Add Vlans and Trunks


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Add Vlans and Trunks


Enable Vtp Client Mode


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Enable Vtp Client Mode


Verify VTP Status


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Verify VTP Status


Confirm VTP Operation


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Confirm VTP Operation


Configure Access Ports


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Configure Access Ports


Extra: VTP Pruning


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Extra: VTP Pruning



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Troubleshooting VTP Connections




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Incompatible VTP Versions- VTP Password Issues


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Incompatible VTP Versions VTP Password Issues


Incorrect VTP Domain Name


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Incorrect VTP Domain Name


Switches Set to VTP Client Mode


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Switches Set to VTP Client Mode


It is possible to change the operating mode of all switches to VTPclient. By doing so, you lose all ability to create, delete, and manageVLANs within your network environment.

Because the VTP client switches do not store the VLAN information inNVRAM, they need to refresh the VLAN information after a reload.

Incorrect Revision Number


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Managing VLANs on a VTP Server


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g g


Managing VLANs on a VTP Server


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Summary


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y



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Configure trunk links Switch SERVER:

(config)# vtp version {1 |2}

(config)# vtp domain {name}

(config)# vtp password {password}(config)#vtp mode server



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Switch CLIENT:(config)# vtp version {1 |2}

(config)# vtp domain {name}

(config)# vtp password {password}

(config)#vtp mode client



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SW2#debug sw-vlan vtp events


ccna exp3 - chapter04 - vtp.ppt [compatibility mode]

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