Getting started with VLAN's.....

[paul.thomas]

Hi Guys

Currently we have an Avaya IP Office switch running on the same network as our PC clients.

I would like to seperate the two network into 2 VLAN's.

We have a mixture of Catalyst 3750 switches and some older 3500 models.

Where do I start?

Should I leave the PC's and servers on the default VLAN and just move the IP handsets?

Any advice, links, background reading etc. appreciated!

[Latchum Naidu]

Hi Paul,

Keeping IP handsets (I think these are IP phones) in a seperate network is always better idea.
Also PC's (user computers) and Servers needs to be seperated as users work on computers and servers will be managed by only Admins and should not be accessible users.

So you need to have three seperate networks IP phones, user PC's and Servers.

What you can do is, if you are sure that IP phones, user pc's and servers are not morethan 254 I mean /24 network then Yes you can devide the existing network. In this way you may need to change the IP address of each ones (if some are fall in the same allocated network then you can just change their default gateway)

If you are not sure that all are only 254 or less then you can use seperate /24 network for each one like...

10.10.28.0/24 for IP phones
10.10.29.0/24 for user PC's
10.10.30.0/24 for Servers
Of course this is the best idea as may be in future your network can expand.

Now to create a VLAN's in 3750 switch, please see the below links.

http://www.cisco.com/en/US/products/hw/switches/ps5023/products_configuration_example09186a00801cc828.shtml
http://www.velocityreviews.com/forums/t41333-help-on-vlan-configuration-catalyst-3750-a.html

Hope the above clear and understand you.
Please rate all the helpfull posts.
Regards,
Naidu.

[paul.thomas]

Thanks for the fast response and detailed reply.

I am stuck with using the same subnet for all as it's the only one allocated to us in the Corporate WAN.

However I do feel we need to segregate the voice and data traffic. I don't believe the network is overly congested, but it makes sense to do this before we get a new phone system later this year.

I will read the links and ask additional questions later.

Thanks

Paul

[Latchum Naidu]

You are most welcome.
So, you can use the existing subnet for data and ovice then.
What you can do is you can segregate the exsting subnet, I think it is /24 is it right?

Remember to rate the helpfull posts as it will encourage the others throughout this great CSC.

Please rate all the helpfull posts.
Regards,
Naidu.

[bridgepartners]

Paul

Generally speaking it is a good idea to separate IP phones and PCs by using VLANs. You can also separate your servers if you want. It is crucial to understand, though, that there will be no communication between VLANs so if you are going to use VLANs you will need to set up some kind of routing device to route traffic between them. A server can do this, or a router or a layer 3 switch like  your 3750. If you follow the logic of this you will see that you need a separate subnet for each VLAN, otherwise the router will not know to route the packets. If you cannot accomodate separate subnets because of your corporate policies then I think that this change cannot be done.

You could consider creating a VLAN for phones that the rest of the corporate network cannot route to by using a private IP range that is not in use elsewhere on the network. Obviously, you would want to discuss this with the network manager first. Often IP phones have a two port switch to accomodate a daisy-chained PC. In this case you can get the phone to select the phone VLAN for itself and pass on the 'normal' LAN to the PC.

Daniel

[paul.thomas]

Are there any good online guides to getting started with Cisco VLAN's?

[nkarpysh]

Possibly good to start with any of these:

http://www.cisco.com/en/US/tech/tk389/tk689/tech_configuration_examples_list.html#anchor3

Nik