rowing more bandwidth at the problem will not always fix it.' Knowing the difference is what makes you, the engineer, valuable to management. If you have a T1 link and you're dropping 50 percent of your packets, assuming there are no physical layer problems, you prob- ably need more bandwidth. If you're running VoIP over a T1 and the calls are choppy, adding more bandwidth may not solve your problem, because the problem probably isn't simply a matter of band- width. The key here again is congestion. If you've got choppy calls and your links aren't congested, you need QoS to prioritize those voice packets SO they get delivered first. QoS Prevents Packets from Being Dropped If you've got a problem with excessive packet drops, QoS will likely not solve it. What QoS will do for you is help you get the important packets through SO that only the less important packets get dropped. Traffic shaping can prevent packets from being dropped (assuming certain buffers are not similarly saturated), though this gets complicated, as you'll see. Additionally, traffic shaping only buffers packets to a point, SO if you're oversubscribing your link all day long, traffic shaping won't help you. QoS Will Make You More Attractive to the Opposite Sex Sad to say, I'm afraid this isn't true either, though in theory, it is possible that your dream date could be reading this very book right now! Chapter 31: Introduction to QoS CHAPTER 32 Designing QoS Designing a QoS scheme can be a relatively simple task or a very large project. The scale of the solution depends on the complexity of your network and the needs of your business. As a general rule, I like to plan everything I do with an end-state design in mind. Even if I'm implementing a QoS scheme for a company that currently doesn't have VoIP, I'll design one that assumes VoIP is coming in the future. In this chapter, I'll walk you through designing a QoS scheme for a network that will require VoIP. Designing QoS is a two-part process: first, you must determine the re- quirements for the sy