Communications in VLANS

[dianewalker]

We setup a lab for VLAN's and trunk.  We have 3 Cisco 3560 POE-8 switches.

On switch1 and switch2, the Gig port is setup as Trunk port. On switch2 and switch3, we have VLANS 10 and 20.  The first 4 ethernet ports are in VLAN 10.  The second 4 ethernet ports are in VLAN 20.  How do we setup so that computers on switch3 can communication to computers on switch1?

Attached are the configs and diagrams for switches.  Thanks.

Diane

[Branimir Turk]

Kind of stupid question, have you created VLANs 10 and 20 on switch-1?

Also can you ping both VLAN 10 and 20 IP switch 3 addresses from switch 2?

Branimir

[dianewalker]

Branimir,

You did not ask stupid questions.  From switch 2, I was able to ping both VLAN's on switch 3 and from switch 3, I was able to ping both VLANS on switch 2.  I did not setup VLANS on switch 1.  I thought setting up the Trunk port on switch 1 and switch 2 would eliminate of setting up VLANS on switch 1.  Let me know if I still need to setup VLANs on switch1.   I assume that you use the cross-over cable to connect G0/1 of switch 1 to G0/1 on switch 2.  Please let me know if you have any suggestions.

Thanks

Diane

[Amit Singh]

Hi Diane,

Yes, you have the create required vlans on switch 1.There are two ways to achieve this to get it working :

A. The PC on switch one has to be in either the Vlan 10 or Vlan 20, statically assigned and configure the correct ip address with the correct gateway. Once this is its vlan any switch which is doing the inter-vlan routing it should be able to ping the other vlan PC for ex, from Vlan 10 to Vlan 20 or vice versa.

B. If you want this PC on switch one to be in default Vlan say Vlan 1. You have to create the VLAN 1 SVI on the switch which is doing the inter-vlan routing the assing the VLAN 1 SVI IP as the default gateway on the PC.

HTH,

-amit singh

[dianewalker]

Thanks for your prompt response, Amit.

I followed your step 1.  I was able to ping computers on switch1, switch2, and switch3.  I do not know how to setup step 2.  Do you think you can help me with the configuration on your step 2?

Question:  Do I still need to setup the Trunk port on switch1 and switch2 using your step 1?   If I still want to setup Trunk port, is there a way to set it up so that computers on switch3 can communicate to computers on switch1?

Please let me know if my questions are not clear.  I am new learning VLANS and trunking and I do not know what I am doing.

Thanks.

Diane

[Amit Singh]

Hi Diane,

Have you created the Vlan interfaces on Switch1? It doesnot really matter by the way as either the switch 2 or switch 3 will do the inter-vlan routing for you between the vlans. You have to configure the trunk ports on all the switches. Here is what you need to do on in order to get my step 2 working.

1. All the switches will have Vlan1 by default. Configure the port on Switch 1 where the PC is connected to Vlan 1.

conf t

int x/y

switchport mode access

switchport access vlan 1

2. If you have created vlan interface on switch 1 for Vlan 10 and 20, then create the Vlan interface for Vlan1 on switch 1, else create the interface vlan 1 on either switch 2 or Swtch 3.

Conf t

interface vlan 1

ip address 192.168.1.254 255.255.255.0

Once you SVI's configured for all the Vlans on either of the switch, you should be able to route/ping the PC' in other vlans.

3. Assign the correct gateway and ip address on the PC for vlan 1.

HTH, Please rate if it does.

Cheers,

-amit singh

[dianewalker]

Amit,

Thanks for your prompt response.  Since I am new learning VLANs and trunking, I will be thinking about your configurations.  I will try your suggestions and get back to you.  I already setup VLANS on switch 1.  But, it is OK.  I will try both your configurations and get back to you. Thanks for your help.

Diane