How to configure Trunking between VLANs with 802.1q?

Trunk link is used to carry the different VLANs traffic on a single link. There are two different protocols are used for Ethernet trunking, 802. 1q and ISL. Trunking change the formatting of the packets. The ports need to be in agreement as to which format is being use to transmit data on the trunk, if there is different trunking encapsulation on the two ends of the link they will not able to communicate. Similar situation will occur if one of your ports is configured in trunking mode and other one as in access mode.















First create multiple VLANs with name, assign multiple ports to them then create 802.1q trunk link between the two switches to allow communication between VLANs.

To create a VLAN, first enter global configuration mode to run the following commands.

Configuration to create VLAN 2 and 3 on switch A

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#vlan 2 (defining the vlan 2)

SwitchA(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchA(config)#vlan 3 (defining the vlan 3)

SwitchA(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchA(config)#exit (exit from vlan 3)



Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 2)

SwitchA(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 3)



Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 4)

SwitchA(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 5)



Configuration to create VLAN 2 on switch B

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#vlan 2 (defining the vlan 2)

SwitchB(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchB(config)#vlan 3 (defining the vlan 3)

SwitchB(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchB(config)#exit (exit from vlan 3)



Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 2)

SwitchB(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 3)



Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 4)

SwitchB(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 5)



Trunking with 802.1q

Now create 802.1q trunk link between the two switches to allow communication between VLANs.

On both switches, SwitchA and SwitchB type the following command with 802.1q at the fastethernet 0/1 interface.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchA(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchA(config-if)#end (exit from interface 1)

SwitchB(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchB(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchB(config-if)#end (exit from interface 1)

To verify that fastethernet 0/1 has been established as trunk port, type the show interface fastethernet 0/1 switchport at the privileged EXEC mode.

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How to configure Trunking between VLANs with ISL?

How to configure Trunking between VLANs with ISL?
Trunking is a technique to carry different VLAN traffic using point to point link between two devices. ISL (InterSwitch Link) is a cisco proprietary protocol can work with Ethernet token ring and Fddi also. Trunking changes the formatting of the packets. The ports need to be in agreement as to which format is being use to transmit data on the trunk, if there is different trunking encapsulation on the two ends of the link they will not able to communicate. Similar situation will occur if one of your ports is configured in trunking mode and other one as in access mode.

http://www.computeronlinetips.com/images/trunking_isl.jpg


First create multiple VLANs with name, assign multiple ports to them then create ISL trunk link between the two switches to allow communication between VLANs.
To create a VLAN, first enter global configuration mode to run the following commands.
Configuration to create VLAN 2 and 3 on switch A
SwitchA(config)#configure terminal (enter in global configuration mode)
SwitchA(config)#vlan 2 (defining the vlan 2)
SwitchA(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)
SwitchA(config)#vlan 3 (defining the vlan 3)
SwitchA(config)#vlan 3 name management (assigning the name management to vlan 3)
SwitchA(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.
SwitchA(config)#configure terminal (enter in global configuration mode)
SwitchA(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)
SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)
SwitchA(config-if)#exit (exit from interface 2)
SwitchA(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)
SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)
SwitchA(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.
SwitchA(config)#configure terminal (enter in global configuration mode)
SwitchA(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)
SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)
SwitchA(config-if)#exit (exit from interface 4)
SwitchA(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)
SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)
SwitchA(config-if)#exit (exit from interface 5)

Configuration to create VLAN 2 on switch B
SwitchB(config)#configure terminal (enter in global configuration mode)
SwitchB(config)#vlan 2 (defining the vlan 2)
SwitchB(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)
SwitchB(config)#vlan 3 (defining the vlan 3)
SwitchB(config)#vlan 3 name management (assigning the name management to vlan 3)
SwitchB(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.
SwitchB(config)#configure terminal (enter in global configuration mode)
SwitchB(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)
SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)
SwitchB(config-if)#exit (exit from interface 2)
SwitchB(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)
SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)
SwitchB(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.
SwitchB(config)#configure terminal (enter in global configuration mode)
SwitchB(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)
SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)
SwitchB(config-if)#exit (exit from interface 4)
SwitchB(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)
SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)
SwitchB(config-if)#exit (exit from interface 5)

Trunking with ISL
Now create ISL trunk link between the two switches to allow communication between VLANs.
On both switches, SwitchA and SwitchB type the following command with ISL at the fastethernet 0/1 interface.
SwitchA(config)#configure terminal (enter in global configuration mode)
SwitchA(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)
SwitchA(config-if)#switchport mode trunk (set port 1 as trunk port)
SwitchA(config-if)#switchport trunk encapsulation isl
SwitchA(config-if)#end (exit from interface 1)
SwitchB(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)
SwitchB(config-if)#switchport mode trunk (set port 1 as trunk port)
SwitchB(config-if)#switchport trunk encapsulation isl
SwitchB(config-if)#end (exit from interface 1)

To verify that fastethernet 0/1 has been established as trunk port, type the show interface fastethernet 0/1 switchport at the privileged EXEC mode.

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How to configure Trunking between VLANs with 802.1q

Trunk link is used to carry the different VLANs traffic on a single link. There are two different protocols are used for Ethernet trunking, 802. 1q and ISL. Trunking change the formatting of the packets. The ports need to be in agreement as to which format is being use to transmit data on the trunk, if there is different trunking encapsulation on the two ends of the link they will not able to communicate. Similar situation will occur if one of your ports is configured in trunking mode and other one as in access mode.

First create multiple VLANs with name, assign multiple ports to them then create 802.1q trunk link between the two switches to allow communication between VLANs.

To create a VLAN, first enter global configuration mode to run the following commands.

Configuration to create VLAN 2 and 3 on switch A

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#vlan 2 (defining the vlan 2)

SwitchA(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchA(config)#vlan 3 (defining the vlan 3)

SwitchA(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchA(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 2)

SwitchA(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 4)

SwitchA(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 5)

Configuration to create VLAN 2 on switch B

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#vlan 2 (defining the vlan 2)

SwitchB(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchB(config)#vlan 3 (defining the vlan 3)

SwitchB(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchB(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 2)

SwitchB(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchB(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchB(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchB(config)#configure terminal (enter in global configuration mode)

SwitchB(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 4)

SwitchB(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchB(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchB(config-if)#exit (exit from interface 5)

Trunking with 802.1q

Now create 802.1q trunk link between the two switches to allow communication between VLANs.

On both switches, SwitchA and SwitchB type the following command with 802.1q at the fastethernet 0/1 interface.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchA(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchA(config-if)#end (exit from interface 1)

SwitchB(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchB(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchB(config-if)#end (exit from interface 1)

To verify that fastethernet 0/1 has been established as trunk port, type the show interface fastethernet 0/1 switchport at the privileged EXEC mode.

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How to configure VTP Client and Server?

VTP (VLAN Trunking Protocol) is the protocol that propagates the information about which VLANs exist from one switch to another switch. If VTP did not provide this information, VLANs would have to be created on all switches individually in the network.

VTP is a Cisco proprietary protocol. The default mode of a switch is configured as VTP server. In any case, the server services are turned off, use the following command to turn it back on as VTP server.

• SwitchA#vlan database
• SwitchA(vlan)#vtp server
• SwitchA(vlan)#exit

First create multiple VLANs with name, assign multiple ports to them then create 802.1q trunk link between the two switches to allow communication between VLANs.

To create a VLAN, first enter global configuration mode to run the following commands.

Configuration to create VLAN 2 and 3 on switch A (VTP server)

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#vlan 2 (defining the vlan 2)

SwitchA(config)#vlan 2 name marketing (assigning the name marketing to vlan 2)

SwitchA(config)#vlan 3 (defining the vlan 3)

SwitchA(config)#vlan 3 name management (assigning the name management to vlan 3)

SwitchA(config)#exit (exit from vlan 3)

Now assigning the ports 2 and 3 to VLAN 2, it must be done from the interface mode. Enter the following commands to add port 2 and 3 to VLAN 2.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/2 (select the Ethernet 0 of port 2)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 2)

SwitchA(config)#interface fastethernet 0/3 (select the Ethernet 0 of port 3)

SwitchA(config-if)#switchport access vlan 2 (allot the membership of vlan 2)

SwitchA(config-if)#exit (exit from interface 3)

Now assigning the ports 4 and 5 to VLAN 3, enter the following commands to add port 4 and 5 to VLAN 3.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/4 (select the Ethernet 0 of port 4)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 4)

SwitchA(config)#interface fastethernet 0/5 (select the Ethernet 0 of port 5)

SwitchA(config-if)#switchport access vlan 3 (allot the membership of vlan 3)

SwitchA(config-if)#exit (exit from interface 5)

Configuration of VTP client on switch B

SwitchB#vlan database

SwitchB(vlan)#vtp client

SwitchB(vlan)#vtp domain group1

SwitchB(vlan)#exit

Trunking with 802.1q

Now create 802.1q trunk link between the two switches to allow communication between VLANs.

On both switches, SwitchA and SwitchB type the following command with 802.1q at the fastethernet 0/1 interface.

SwitchA(config)#configure terminal (enter in global configuration mode)

SwitchA(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchA(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchA(config-if)#end (exit from interface 1)

SwitchB(config)#interface fastethernet 0/1 (select the Ethernet 0 of port 1)

SwitchB(config-if)#switchport mode trunk (set port 1 as trunk port)

SwitchA(config-if)#switchport trunk encapsulation dot1q

SwitchB(config-if)#end (exit from interface 1)

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