voip subnet/vlan on 2950 2

[elmurado]

Hi, we've setup a new Avaya IP403 phone system to replace the old Panasonic.
We've been advised that if we ever want to move from digital to VoIp then we will need to setup a VLAN to have the two different types of traffic(voice vs data) on a separate (logical?) subnet.
I can see the reasoning(eg delays on VoIP traffic not good for conversations)
Can a 2950 separate/differntiate between traffic 'types' as I can't see the point of having a VLAN which is differentiated by MAC address etc as a solution to this.

Any tips on where I should start--I've already got a few good white papers from Cisco on this. A book would be handy or just advice from people who've done something similar.

Looking at a user environment of 50 users.

TIA

 

[ADB100]

Depending on your network size and traffic patterns, plus who will manage the extra complexity you could get away with a single VLAN. The recommendations seem to be to have one Data & one Voice VLAN per access switch. All of the newer cisco switches support Voice VLAN's; this is where each access port as well as having an access VLAN (data VLAN) they have one additional 802.1q tagged VLAN for voice. You must inform the IP Phones to use this VLAN (and there are several ways to implement this depending on the manufacturer of the IP Phones).
There are no Cisco switches that directly support MAC-based VLAN's, but there are other products such as URT or Cat-5000-based VMPS, but these are all end of life. MAC-based VLAN's are in my opinion an administrative nightmare anyway and should be avoided.

You don't mention any other switches so I assume you have a small network with no or limited Layer-3 capacity, in which case it may not be worth implementing Voice VLAN's.

Andy

 

[DrGryphon]

Yes, Cisco switch IOS allows you to specify per port what the vlan for both voice and data should be (actually, it trunks, so you can have a phone usign that switchport, and then a PC attached to a phone on a different VLAN).

I don't know non-Cisco hardware will interoperate with this.

Separate voice and data VLANs (performance aside) is increasingly important for security reasons.

The original Citrix Guru...

http://www.citrixguru.com

 

[elmurado]

Thanks guys--I'm going to wade through the Cisco docs soon.

I'm guessing that any routers connected to these switches also need the capability of having separate configurable interfaces for different subnets too. Is that right?

 

[DrGryphon]

As far as I know no router IOS yet has a direct equivalent. I guess it is not so important because the configuration here is quite static.

Normally I will have a dot1q trunk from one of the switches to the router, then have ethernet subinterfaces on the router and configure each one for either voice or data vlan. On busier routers I have 2 ethernet interfaces and have data on one and voice on the other.

Not all router IOS has ethernet subinterfaces though... so check that.

The original Citrix Guru...

http://www.citrixguru.com