How to connect inter VLANs?

Hi there,

Im beginner here,need advises from experts here

OK,let me start, i have setup simple networking system for connection between two VLANs using 2950 switch and 1841 router. The problem is I dont know how to configure 1841 router to enable VLAN1 and VLAN2 to communicate each other(to enable PC VLAN1 can ping PC VLAN2).Please refer the diagram:


Please advise me how to configure 1841 router to make VLAN1 and VLAN2 can communicate.

Thanks

Good evening,

For communication to work between VLAN's, there are two configurations you can choose from.

1. Traditional Inter-VLAN Routing
2. Router-on-a-stick

For the topology you have provided, Router-on-a-stick would work best, since you are only using one router interface.

You will need to make the link between the router and switch a trunk link and assign sub-interfaces to the connected router interface. (i.e. For Fa0/0 you would have Fa0/0.10 and Fa0/0.20) Follow? Assign VLAN 10 to sub-interface Fa0/0.10 and VLAN 20 to Fa0/0.20.

Before you assign IP addresses to the sub-interfaces, you must configure an encapsulation method (i.e. dot1q) on the router for EACH INTERFACE.

Assign IP addresses to the sub-interfaces according to the subnet used in each corresponding VLAN AFTER the previous step.

You will receive an error if you do otherwise.

[code:1]R1(config)# interface fa0/0.10
R1(config-subif)# encapsulation dot1q 10
R1(config-subif)# ip address 10.10.10.1 255.255.255.0[/code:1]

Follow?

At last someone have replied my question,thanks beepee

Ok,i'll give the some details.Basically i have setup VLAN10 and VLAN20:

VLAN 10 (192.168.1.1/24)
-PC1 (192.168.1.2/24)
-PC2 (192.168.1.3/24)

VLAN 20 (192.168.2.1/24)
-PC3 (192.168.2.2/24)
-PC4 (192.168.2.3/24)


In router mode, I have configured:

---

Router(config-if)#no ip address

Router(config-if)#no shutdown

---VLAN 10----
Router(config-if)#int fastethernet 0/0.10

Router(config-subif)#encapsulation dot1q 10

Router(config-subif)#ip address 192.168.1.4 255.255.255.0

---VLAN 20----
Router(config-if)#int fastethernet 0/0.20

Router(config-subif)#encapsulation dot1q 20

Router(config-subif)#ip address 192.168.2.4 255.255.255.0

---

but still I cannot ping between host in VLAN10 and VLAN20. Did I miss something or wrong configuration?

have you set gateway for the both pc at vlan 10 & vlan 20?

From PC2(Vlan 1) , try to ping to gateway 1st before you ping to pc5(Vlan2).

have you set gateway for the both pc at vlan 10 & vlan 20?

From PC2(Vlan 1) , try to ping to gateway 1st before you ping to pc5(Vlan2).

yes. I have set the gateway. I can ping from PC2(VLAN1) 192.168.1.3 to its gateway 192.168.1.1.

But cannot ping from PC2(VLAN1) 192.168.1.3 to router VLAN1 interface 192.168.1.4.

Anyone?

ermmm....let's try review step by step...

1- Switch Configuration

//Create Vlan At Switch level //

Switch#
Switch#vlan database
Switch(vlan)#vlan 10
VLAN 10 added:
Name: VLAN0010
Switch(vlan)#vlan 20
VLAN 20 added:
Name: VLAN0020
Switch(vlan)#apply
APPLY completed.
Switch(vlan)#

//Assume Switch connected to router using port f0/24 //

Switch(config)#int f0/24
Switch(configif)#switchport trunk encapsulation dot1q
Switch(configif)#switchport mode trunk
Switch(configif)#

//Assume PC1 using port f0/1 at switch level //
Switch(configif)#
Switch(configif)#int f0/1
Switch(configif)#switchport access vlan 10
Switch(configif)#switchport mode access

//Assume PC2 using port f0/2 at switch level //
Switch(configif)#
Switch(configif)#int f0/2
Switch(configif)#switchport access vlan 20
Switch(configif)#switchport mode access
Switch(configif)#
Switch#wr