Here's another question that's come in.
Reader Question:
Hi Ken,
Here's a general questions ~ do we really need to enable QoS in our network prior to adding VoIP traffic? Our network has lots of bandwidth and usually utilization is less than 10%.  Look forward to your insights.

It's a great question, but the answer isn't one that you'll like. It's a common answer in networking and one that nobody likes.

It depends.

The answer depends on so many variables, and that's what makes it challenging to figure out how to answer.

If your network is underutilized and overengineered, you might not need to implement QoS. You may be able to defer QoS until later. The question there is whether your network is really underutilized or overengineered. Too often networks are running pretty close to threshholds on performance.

The real key to answering this question lies in how thorough a job you do of performing network readiness assessment ant testing. If your assessment is a generic look at your network and a gut feeling that you can add VoIP without any changes, you could be in for a big disappointment, and problems with call quality.

If you use some of the methodical tools available, like NetIQ's Vivinet Assessor, you may find your network can support your VoIP needs with minimal upgrade. The only well to tell what you need to add, whether it's QoS, bandwidth or anything else, is to perform a comprehensive analysis of what you have today.

You need to inventory the network. You need to review the protocols and traffic types in use today. You need to measure bandwidth, throughput, error rate, packet loss, delay and jitter at a minimum.

The real key to finding the answer is in knowing everything pertinent about your network through a combination of qualitative and quantative measurements.

Technorati Tags: QoS, readiness assessment, network design, VoIP