1. Building Cisco Multilayer Switched Networks (BCMSN)
Instructor Name
MR.SIDDIQ AHMED
CCIE # 17864

2. Implementing VLANs

3. A VLAN = A Broadcast Domain = Logical Network (Subnet)
VLAN Overview
Layer 2 connectivity
Logical organizational flexibility
Single broadcast domain
Management
Basic security
Purpose:
Emphasize: A VLAN is a broadcast domain.
Note: In order to have inter-VLAN communications, a router is required.
A VLAN = A Broadcast Domain = Logical Network (Subnet)

4. VLANs Establish Broadcast Domains
Purpose: VLANs create broadcast domains that can greatly reduce unnecessary traffic
Emphasize:
VLANs can create multiple broadcast domains
Transition:
Lets take a look at an example of network that has implemented VLANs to complete our review
VLANs plus routing limits broadcasts to the domain of origin.

5. Local VLANs Local VLANs generally reside in the wiring closet.
Purpose: This page discusses the characteristics of local VLANs.
Emphasize:
Local VLANs are sometimes referred to a Geographic VLANs. Local VLANs are assigned based on a physical location like a wiring closet, wing, or building of a corporation. They allow for a deterministic approach to Layer 3 routing, Spanning Tree Protocol behavior, etc. They also make the management process much easier. Local VLANs facilitate the new Campus Model rule of 20/80 or 20% of your traffic is local, 80% of your traffic is remote.
Transition:
Now that you have finished discussing the types of VLANs what are the configuration options for VLANs?
Local VLANs generally reside in the wiring closet.

6. All users attached to same switch port must be in the same VLAN.
Static VLANs
Purpose: Provide the student with the basic information
Emphasize:
Slide contents
Transition:
All users attached to same switch port must be in the same VLAN. 25 28 8 25

7. VLAN Membership Modes VLAN membership can either be static or dynamic.
Note: Once a port has been assigned to a VLAN, it cannot send or receive traffic from devices in another VLAN without the intervention of a Layer 3 device like a router.
The 1900 can’t be configure as the VMPS.
A CiscoWorks 2000 or CWSI management station or a Catalyst 5000 switch can be configured as the VMPS.
In the future, dynamic VLANs may also offer membership based on other criteria such as protocol or application. Dynamic VLANs are covered in the Managing Cisco Switched Internetworks class.
VLAN membership can either be static or dynamic.

8. Configuring VLANs in Global Mode
Switch#configure terminal
Switch(config)#vlan 3
Switch(config-vlan)#name Vlan3
Switch(config-vlan)#exit
Switch(config)#end

9. Configuring VLANs in VLAN Database Mode
Switch#vlan database
Switch(vlan)#vlan 3
VLAN 3 added:
Name: VLAN0003
Switch(vlan)#exit
APPLY completed.
Exiting....

10. Assigning Access Ports to a VLAN
Switch(config)#interface gigabitethernet 1/1
Enters interface configuration mode
Switch(config-if)#switchport mode access
Configures the interface as an access port
Switch(config-if)#switchport access vlan 3
Assigns the access port to a VLAN

11. Verifying the VLAN Configuration
Switch#show vlan [id | name] [vlan_num | vlan_name]
VLAN Name Status Ports
1 default active Fa0/1, Fa0/2, Fa0/5, Fa0/7
Fa0/8, Fa0/9, Fa0/11, Fa0/12
Gi0/1, Gi0/2
2 VLAN active
51 VLAN active
52 VLAN active …
VLAN Type SAID MTU Parent RingNo BridgeNo Stp BrdgMode Trans1 Trans2
1 enet
2 enet
51 enet
52 enet

12. Verifying the VLAN Port Configuration
Switch#show running-config interface {fastethernet | gigabitethernet} slot/port
Displays the running configuration of the interface
Switch#show interfaces [{fastethernet | gigabitethernet} slot/port] switchport
Displays the switch port configuration of the interface
Switch#show mac-address-table interface interface-id [vlan vlan-id] [ | {begin | exclude | include} expression]
Displays the MAC address table information for the specified interface in the specified VLAN

13. Implementing VLAN Trunks

14. Trunk Link Physical Implementation

15. VLAN Trunking

16. Switch Ports and Trunk Ports
Command
Function
switchport mode access
Access port
Sets the switch port to unconditionally be an access port
switchport mode trunk
Trunk port
Sets the switch port to unconditionally become a trunk port
switchport mode dynamic
Dynamic port
Sets the switch port to dynamically negotiate the status (access or trunk)

17. Switch Port DTP Modes Mode Function access
Unconditionally sets a switch port to access mode, regardless of other DTP functions
trunk
Sets the switch port to unconditional trunking mode and negotiates to become a trunk link, regardless of neighbor interface mode
nonegotiate
Specifies that DTP negotiation packets are not sent on the Layer 2 interface
dynamic desirable
Sets the switch port to actively send and respond to DTP negotiation frames. Default for Ethernet
dynamic auto
Sets the switch port to respond but not to actively send DTP negotiation frames

18. ISL Encapsulation Performed with ASIC
Not intrusive to client stations; client does not see the header
Effective between switches, and between routers and switches
Note: The 1900 only supports ISL trunking.
ISL is Cisco proprietary Q is an IEEE standard.
Other trunk types:
LANE (VLANSs over ATM)
(FDDI trunk)

19. ISL and Layer 2 Encapsulation

20. 802.1Q Frame

21. 802.1Q and Layer 2 Encapsulation

22. 802.1Q Native VLANs

23. Cisco defaults for FDDI and Token Ring For Ethernet VLANs only
VLAN Ranges
VLAN Range
Range
Usage
0, 4095
Reserved
For system use only 1
Normal
Cisco default
2-1001
Normal
For Ethernet VLANs
Cisco defaults for FDDI and Token Ring
Normal
Extended
For Ethernet VLANs only

24. Configuring ISL Trunking
Switch(config)#interface fastethernet 2/1
Enters interface configuration mode
Switch(config-if)#switchport trunk encapsulation isl
Selects the encapsulation
Switch(config-if)#switchport mode trunk
Configures the interface as a Layer 2 trunk

25. Verifying ISL Trunking
Switch#show running-config interface {fastethernet | gigabitethernet} slot/port
Switch#show interfaces [fastethernet | gigabitethernet] slot/port [ switchport | trunk ]
Switch#show interfaces fastethernet 2/1 trunk
Port Mode Encapsulation Status Native VLAN
Fa2/1 desirable isl trunking
Port VLANs allowed on trunk
Fa2/
Port VLANs allowed and active in management domain
Fa2/ ,
Port VLANs in spanning tree forwarding state and not pruned

26. Configuring 802.1Q Trunking
Switch(config)#interface fastethernet 5/8 Switch(config-if)#shutdown Switch(config-if)#switchport trunk encapsulation dot1q Switch(config-if)#switchport trunk allowed vlan 1,15,11, Switch(config-if)#switchport mode trunk Switch(config-if)#switchport nonegotiate Switch(config-if)#no shutdown

27. Verifying 802.1Q Trunking
Switch#show running-config interface {fastethernet | gigabitethernet} slot/port
Switch#show interfaces [fastethernet | gigabitethernet] slot/port [ switchport | trunk ]
Switch#show interfaces gigabitEthernet 0/1 switchport
Name: Gi0/1
Switchport: Enabled
Administrative Mode: trunk
Operational Mode: trunk
Administrative Trunking Encapsulation: dot1q
Operational Trunking Encapsulation: dot1q
Negotiation of Trunking: On
Access Mode VLAN: 1 (default)
Trunking Native Mode VLAN: 1 (default)
Trunking VLANs Enabled: ALL
Pruning VLANs Enabled:
. . .

28. Implementing VLAN Trunk Protocol

29. VTP Protocol Features Advertises VLAN configuration information
Maintains VLAN configuration consistency throughout a common administrative domain
Sends advertisements on trunk ports only
Notes: VTP is a Cisco proprietary feature. VTP is a Layer 2 messaging protocol that maintains VLAN configuration consistency by managing the addition, deletion, and renaming of VLANs on a network-wide basis. VTP minimizes misconfigurations and configuration inconsistencies that can cause several problems, such as duplicate VLAN names, incorrect VLAN-type specifications, and security violations.
A VTP domain (also called a VLAN management domain) is one switch or several interconnected switches sharing the same VTP domain. A switch is configured to be in only one VTP domain. You make global VLAN configuration changes for the domain by using the Cisco IOS command-line interface (CLI), Cisco Visual Switch Manager Software, or Simple Network Management Protocol (SNMP).
By default, a 1900 switch is in the no-management-domain state until it receives an advertisement for a domain over a trunk link or you configure a management domain.
The default VTP mode is server mode, but VLANs are not propagated over the network until a management domain name is specified or learned. If the switch receives a VTP advertisement over a trunk link, it inherits the management domain name and configuration revision number. The switch then ignores advertisements with a different management domain name or an earlier configuration revision number.
When you make a change to the VLAN configuration on a VTP server, the change is propagated to all switches in the VTP domain. VTP advertisements are transmitted out all trunk connections, including Inter-Switch Link (ISL), IEEE Q, IEEE , and ATM LAN Emulation (LANE).
If you configure a switch from VTP transparent mode, you can create and modify VLANs, but the changes are not transmitted to other switches in the domain, and they affect only the individual switch.

30. VTP Operation VTP advertisements are sent as multicast frames.
VTP servers and clients are synchronized to the latest revision number.
VTP advertisements are sent every 5 minutes or when there is a change.
Layer 2 of 2
Emphasize: The latest revision number is what the switches will synchronize to.

31. VTP Modes Creates, modifies, and deletes VLANs
Sends and forwards advertisements
Synchronizes VLAN configurations
Saves configuration in NVRAM
Cannot create, change, or delete VLANs
Forwards advertisements
Synchronizes VLAN configurations
Does not save in NVRAM
Creates, modifies, and deletes VLANs locally only
Forwards advertisements
Does not synchronize VLAN configurations
Saves configuration in NVRAM
Emphasize: Default VTP mode on the Catalyst switches is server. Be careful when adding new switches into an existing network. This is covered in more detail later.

32. VTP Pruning
Increases available bandwidth by reducing unnecessary flooded traffic
Example: Station A sends broadcast, and broadcast is flooded only toward any switch with ports assigned to the red VLAN.
Emphasize: VTP prunning provides optimized flooding. Without VTP prunning, station A’s broadcast will be flooded to all switches whether they have any port in the red VLAN or not.
Note: VLAN1 can’t be prunned. STP, CDP, VTP updates are sent on VLAN1.
All switches in the switched network must support prunning or prunning will be disabled.
Each trunk port maintains a state variable per VLAN indicating if the switch has any port assigned to a particular VLAN or not.

33. VTP Configuration Guidelines
Configure the following:
VTP domain name
VTP mode (server mode is the default)
VTP pruning
VTP password
VTP trap
Use caution when adding a new switch into an existing domain.
Add a new switch in client mode to prevent the new switch from propagating incorrect VLAN information.
Notes: All switches in a VTP domain must run the same VTP version.
The password entered with a domain name should be the same for all switches in the domain. If you configure a VTP password, the management domain will not function properly if you do not assign the management domain password to each switch in the domain.
A VTP version 2-capable switch can operate in the same VTP domain as a switch running VTP version 1, provided version 2 is disabled on the version 2-capable switch (version 2 is disabled by default).
Do not enable VTP version 2 on a switch unless all of the switches in the same VTP domain are version 2-capable. When you enable version 2 on a switch, all of the version 2-capable switches in the domain must have version 2 enabled. If there is a version 1-only switch, it will not exchange VTP information with switches with version 2 enabled.
If there are Token Ring networks in your environment, you must enable VTP version 2 for Token Ring VLAN switching to function properly.
Enabling or disabling VTP pruning on a VTP server enables or disables VTP pruning for the entire management domain.
In the lab, all the switches are set to VTP transparent mode.

34. Configuring a VTP Server
Switch(config)#vtp server
Configures VTP server mode
Switch(config)#vtp domain domain-name
Specifies a domain name
Switch(config)#vtp password password
Layer 2 of 2
Note: The two commands shown in the slide can also be combined into one command:
vtp domain switchlab transparent
Sets a VTP password
Switch(config)#vtp pruning
Enables VTP pruning in the domain

35. Configuring a VTP Server
Switch#configure terminal Switch(config)#vtp server Setting device to VTP SERVER mode. Switch(config)#vtp domain Lab_Network Setting VTP domain name to Lab_Network Switch(config)#end

36. Verifying the VTP Configuration
Switch#show vtp status
Switch#show vtp status
VTP Version : 2
Configuration Revision : 247
Maximum VLANs supported locally : 1005
Number of existing VLANs : 33
VTP Operating Mode : Client
VTP Domain Name : Lab_Network
VTP Pruning Mode : Enabled
VTP V2 Mode : Disabled
VTP Traps Generation : Disabled
MD5 digest : 0x45 0x52 0xB6 0xFD 0x63 0xC8 0x49 0x80
Configuration last modified by at :04:49
Switch#

37. Tomorrow's Topics : Spanning Tree Protocol (STP)
Rapid Spanning Tree Protocol (RSTP)
Multiple Spanning Tree Protocol (MSTP)