Transcript No Slide Title

Chap 4 – Implement VTP
Learning Objectives
•
•
•
Explain the role of VTP in a converged
switched network
Describe the operation of VTP: VTP
domains, VTP Modes, VTP
Advertisements, and VTP Pruning.
Configure VTP on the switches in a
converged network.
1
Chapter 4
VLAN Trunking Protocol (VTP)
Before discussing VTP, it is important to understand that VTP is
not necessary in order to configure VLANs or Trunking on Cisco
Switches.
•
•
•
•
VTP is a Cisco proprietary protocol that allows VLAN configuration
to be consistently maintained across a common administrative
domain.
VTP minimises the possible configuration inconsistencies that arise
when changes are made.
Additionally, VTP reduces the complexity of managing and
monitoring VLAN networks, allowing changes on one switch to be
propagated to other switches via VTP.
On most Cisco switches, VTP is running and has certain defaults
already configured.
2
Chapter 4
1. Create
VLAN 40 on
S1 – VTP
server
VTP Operation
Computer
•VTP allows a network manager to makes changes on a switch that is
configured as a VTP server. The VTP server distributes and
synchronizes VLAN information to VTP-enabled switches throughout
the switched network,
S1
PC1
172.17.10.21/24
Fa0/1
Computer
VLAN 40
Fa0/2
Fa0/11
PC2
172.17.20.22/24
Fa0/18
Computer
Fa0/11
S2
Fa0/1 Fa0/2
S3
Fa0/18
Computer
PC5
172.17.20.25/24
Computer
Fa0/6
PC3
172.17.30.23/24
PC4
172.17.10.24/24
VLAN 40
2. VTP propagates VLAN 40
to S2 & S3 – VTP clients
Computer
Fa0/6
Computer
PC6
172.17.30.26/24
VTP stores VLAN configurations in the VLAN database called vlan.dat.
3
Chapter 4
VTP Components
•
•
•
•
•
•
•
VTP Domain - consists of one or more interconnected switches. All switches in a domain
share VLAN configuration details using VTP advertisements. A router or Layer 3 switch
defines the boundary of each domain.
VTP Advertisements - used to distribute and synchronize VLAN configurations across
the network.
VTP Modes - a switch can be configured in one of three modes: server, client, or
transparent.
VTP Server - store the VLAN information for the entire domain in NVRAM. The server
is where VLAN can created, deleted, or renamed for the domain.
VTP Client - VTP clients function the same way as VTP servers, but you cannot create,
change, or delete VLANs on a VTP client. A VTP client only stores the VLAN information
for the entire domain while the switch is on. A switch reset deletes the VLAN
information.
VTP Transparent - forwards VTP advertisements to VTP clients and VTP servers, but do
not participate in VTP. VLANs that are created, renamed, or deleted on transparent
switches are local to that switch only.
VTP Pruning - VTP pruning increases network available bandwidth by restricting flooded
traffic to those trunk links that the traffic must use to reach the destination devices.
4
Chapter 4
Default VTP Configuration
Sh vtp status
5
Chapter 4
VTP Domains
cisco1
S2
cisco2
S1
S3
6
S5
•VTP allows separation of a
network into smaller
management domains to help
reduce VLAN management
S4
S6
• Until the VTP domain
name is specified,
VLANs cannot be
created or modified on
a VTP server, and VLAN
information is not
propagated over the
network.
Chapter 4
VTP Domain Name Propagation
Computer
cisco2
S1
Server
VTP
Advert
Null0
cisco2
S3
Client
Client
Null0
cisco2
Null0
cisco2
7
The network manager
configures the VTP domain
name as cisco2 on the VTP
server switch S1.
2. The VTP server sends out a
VTP advertisement with the
new domain name embedded
inside.
VTP
Advert
S2
1.
3. The S2 and S3 VTP client
switches update their VTP
configuration to the new
domain name.
Chapter 4
VTP Frame Structure
•A VTP frame consists of a header field and a message field. The VTP
information is inserted into the data field of an Ethernet frame. The Ethernet
frame is then encapsulated as a 802.1Q trunk frame (or ISL frame).
•Each switch in the domain sends periodic advertisements out each trunk port to
a reserved multicast address. These advertisements are received by neighboring
switches, which update their VTP and VLAN configurations as necessary.
8
Chapter 4
VTP Revision Number
•The configuration revision number is a 32-bit number that indicates the level
of revision for a VTP frame.
•The default configuration number for a switch is zero.
•Each time a VLAN is added or removed, the 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 the revision number to zero.
9
Chapter 4
VTP Message Types
•Server and client switches
issue summary
advertisements every 5
minutes. Servers inform
neighbor switches what
they believe to be the
current VTP revision
number
•Clients request VLAN
information from servers
using the advertisement
request.
•Subset advertisements contain
detailed information about VLANs and
are sent by servers in response to an
advertisement request from a client.
10
Chapter 4
VTP Operation - Server
•
•
•
VTP servers can create, modify, 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.
11
Chapter 4
VTP Operation - Client
•
•
•
•
VTP clients cannot create, modify, or delete VLAN information.
The only role of VTP clients is to process VLAN changes and
send VTP messages out all trunk ports.
The VTP client maintains a full list of all VLANs within the VTP
domain, but it does not store the information in NVRAM.
Any changes made must be received from a VTP server
advertisement.
12
Chapter 4
VTP Operation - Transparent
•
•
•
•
Switches in VTP transparent mode forward VTP advertisements but
ignore information contained in the message.
A transparent switch will not modify its database when updates are
received, nor will the switch send out an update indicating a change in
its own VLAN status.
Except for forwarding VTP advertisements, VTP is disabled on a
transparent switch.
There is also an “off” VTP mode in which switches behave the same as
in the VTP transparent mode, except VTP advertisements are not
13
forwarded.
Chapter 4
VTP Pruning
•VTP pruning prevents unnecessary flooding of broadcast information from one
VLAN across all trunks in a VTP domain.
•VTP pruning permits switches to negotiate which VLANs are assigned to ports at
the other end of a trunk and, hence, prune the VLANs that are not assigned to
ports on the remote switch.
•Pruning is disabled by default. VTP pruning is enabled using the vtp pruning global
configuration command on the VTP Server.
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/2
Fa0/11
PC2
VLAN 20
Fa0/18
Computer
Fa0/11
S2
Fa0/1 Fa0/2
S3
Fa0/18
Computer
PC5
VLAN 20
Computer
Fa0/6
PC3
VLAN 10
PC4
VLAN 20
Computer
Fa0/6
Computer
14
PC6
VLAN 20
Chapter 4
VTP Pruning Enabled
S2 will no longer
send VLAN 10
broadcasts out of
Fa0/1
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/2
Fa0/11
PC2
VLAN 20
Fa0/18
Computer
Fa0/11
S2
Fa0/1 Fa0/2
S3
Fa0/18
Computer
PC5
VLAN 20
Computer
Fa0/6
PC3
VLAN 10
PC4
VLAN 20
Computer
Fa0/6
Computer
15
PC6
VLAN 20
Chapter 4
VTP Server Configuration
1. Check VTP revision
number, mode, domain name
(Use reset vtp command to
zeroise revision number)
Server
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/11
PC2
VLAN 20
2. Use vtp domain command
to configure domain name as
‘cisco1’
16
Fa0/18
Fa0/1 Fa0/2
Computer
Fa0/6
PC3
VLAN 30
S2
Client
Computer
Chapter 4
VTP Server Configuration
3. Use vtp version command
to set VTP version
(VTP 1 and VTP are not
compatible)
Server
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/11
PC2
VLAN 20
Fa0/18
17
PC3
VLAN 30
Fa0/1 Fa0/2
Computer
Fa0/6
4. Add VLANs, activate
Fa0/1 trunk
S2
Client
Computer
Chapter 4
VTP Client Configuration
1. Check VTP revision
number, mode, domain name
(Use reset vtp command to
zeroise revision number)
Server
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/11
2. Use vtp mode client
command to configure S2 as
a client
18
PC2
VLAN 20
Fa0/18
Fa0/1 Fa0/2
Computer
Fa0/6
PC3
VLAN 30
S2
Client
Computer
Chapter 4
VTP Client Configuration
3. Check status of trunk and
VTP parameters
Server
S1
PC1
VLAN 10
Fa0/1
Computer
Fa0/11
PC2
VLAN 20
3. Connect trunk cabling,
Check VTP advertisements
being exchanged
19
Fa0/18
Fa0/1 Fa0/2
Computer
Fa0/6
PC3
VLAN 30
S2
Client
Computer
Chapter 4
Troubleshooting VTP
•Incompatible VTP Versions - VTP versions 1 and 2 are incompatible with
each other. Modern Cisco Catalyst switches, such as the 2960, are
configured to use VTP version 1 by default.
•VTP Password Issues - When using a VTP password to control participation
in the VTP domain, ensure that the password is set correctly on all switches
in the VTP domain.
•Incorrect VTP Domain Name - The VTP domain name is a key parameter that
is set on a switch. An improperly configured VTP domain affects VLAN
synchronization between switches. To avoid incorrectly configuring a VTP
domain name, only set the VTP domain name on one VTP server switch.
•All Switches Set to VTP Client Mode - lose all ability to create, delete, and
manage VLANs within a network. To avoid losing all VLAN configurations in a
VTP domain, configure a second switch in the same domain as a VTP server.
20
Chapter 4
Any
Questions?
21
Chapter 4
Chapter 4.4.1 – Basic VTP
Config
Lab Topology
S1
PC1
172.17.10.21/24
Fa0/1
Computer
Fa0/2
Fa0/11
PC2
172.17.20.22/24
Fa0/18
Computer
Fa0/11
S2
Fa0/1 Fa0/2
S3
Fa0/18
Computer
PC5
172.17.20.25/24
Computer
Fa0/6
PC3
172.17.30.23/24
PC4
172.17.10.24/24
Computer
Fa0/6
Computer
22
PC6
172.17.30.26/24
Chapter 4