Below is a diagram of the network I'll be working with in this post.
My goal is for UserA in VLAN 64 to communicate with UserB in VLAN 128. To do this my router and switch must use a fastethernet port running at 100Mb full duplex.
To begin with I will configure the ports on Switch1 to be in the correct VLANs. These commands will also create the VLANs because the don't already exist. I have named the VLANs to be the same as the networks to keep things simple.
Switch1
switch1#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch1(config)#interface range fastEthernet 0/9 - 16
switch1(config-if-range)#switchport access vlan 64
% Access VLAN does not exist. Creating vlan 64
switch1(config-if-range)#exit
switch1(config)#interface range fastEthernet 0/17 - 23
switch1(config-if-range)#switchport access vlan 128
% Access VLAN does not exist. Creating vlan 128
switch1(config-if-range)#end
I have now created the VLANs and I check this with a show command.
switch1#sh vlan brief
VLAN Name Status Ports
---- -------------------------------- --------- -------------------------------
1 default active Fa0/2, Fa0/3, Fa0/4, Fa0/5, Fa0/6, Fa0/7, Fa0/8
2 dmz active
64 VLAN0064 active Fa0/9, Fa0/10, Fa0/11, Fa0/12, Fa0/13, Fa0/14, Fa0/15, Fa0/16
128 VLAN0128 active Fa0/17, Fa0/18, Fa0/19, Fa0/20, Fa0/21, Fa0/22, Fa0/23
1002 fddi-default active
1003 token-ring-default active
1004 fddinet-default active
1005 trnet-default active
On switch2 I configure the port that will be connected to the router as a trunk port. I also configure the port to be fixed at 100Mb full duplex.
Switch2
switch2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
switch2(config)#interface fastEthernet 0/2
switch2(config-if)#speed 100
switch2(config-if)#duplex full
switch2(config-if)#switchport mode trunk
switch2(config-if)#end
I check the configuration using a show command. This tells me which interfaces are trunking and for which VLANs.
switch2#sh interfaces trunk
Port Mode Encapsulation Status Native vlan
Fa0/2 on 802.1q trunking 1
Po5 desirable 802.1q trunking 1
Port Vlans allowed on trunk
Fa0/2 1-4094
Po5 1-4094
Port Vlans allowed and active in management domain
Fa0/2 1-2,64,128
Po5 1-2,64,128
Port Vlans in spanning tree forwarding state and not pruned
Fa0/2 1-2,64,128
Po5 1-2,64,128
On Router2 I create 2 sub-interfaces off the FastEthernet interface (fa0). I name these the same as the VLANs, again to keep thing simple. I also configure the sub-interfaces to support dot1q trunking.
Router2
Router2#conf t
Enter configuration commands, one per line. End with CNTL/Z.
Router2(config)#interface fastEthernet 0.64
Router2(config-subif)#encapsulation dot1Q 64
Router2(config-subif)#ip address 192.168.1.62 2 55.255.255.192
Router2(config-subif)#no shut
Router2(config-subif)#exit
Router2(config)#interface fastEthernet 0.128
Router2(config-subif)#encapsulation dot1Q 128
Router2(config-subif)#ip address 192.168.1.190 2 55.255.255.192
Router2(config-subif)#no shut
Router2(config-subif)#exit
Once the hosts are configured with valid IP addresses and subnet masks (as shown in the diagram) they are given the default gateway of the IP address that the sub-interface was configured with.
UserA
IP Address - 192.168.1.65
Subnet Mask - 255.255.255.192
Default Gateway - 192.168.1.126
UserB
IP Address - 192.168.1.129
Subnet Mask - 255.255.255.192
Default Gateway - 192.168.1.190
Now I will be able communicate between the hosts in the 2 VLANs.
