ueuing is not suitable for voice, but again, low-latency queuing is the QoS method of choice for voice-enabled networks. Low-latency queuing Low-latency queuing (LLQ) is class-based WFQ with a strict priority queue-one in which hardware is used to send packets that need to be sent with the lowest latency possible. This is especially useful for voice and video, where any latency or delay causes problems. LLQ is the preferred method of QoS for voice networks, and is the QoS method I focus on in this book. Traffic shaping Traffic shaping is slightly different from other forms of queuing. Traffic shaping monitors traffic, and when a configured threshold is met, packets are queued until a point where we want them to be sent. Traffic shaping can be employed for better utilization of bandwidth or to properly pace packets for a smaller remote link. The benefits are a smoother use of bandwidth (Figure 31-7) and the fact that packets are buffered and not just dropped. The downside is that traffic shaping requires memory to function, because it buffers packets. Also, if the configured buffer over- flows, packets will be discarded. In the first edition of this book, I commented that traffic shaping is not used for voice and is not often seen in modern networks. I have since proven myself wrong. I love when I'm proven wrong, especially when I prove it myself. In fact, traffic shaping became such a big deal to one of my clients that I decided to add a section on it. Chapter 31: Introduction to QoS Policing Before After Shaping Before After Figure 31-7. Traffic policing versus traffic shaping Traffic-shaping theory I was working in a large retail environment where we had 300+ retail stores all con- necting back to the main office. We were upgrading from Frame Relay service (as low as 256k) to MPLS (full T1) at all sites. The main office upgraded from a DS3 (45 Mbps) to OC3 (155 Mbps). We were also preparing the network for VoIP. We quickly ran into a problem when the MPLS cloud appeared to be dropping packets. It was, but not b