How Traffic Shaping Optimizes Network Bandwidth

As more and more automobiles began to clog city streets in the early 20th century, things got downright dangerous for the traffic cops stationed in busy intersections. Police officer William Potts decided to do something about it. He adapted the automated controls used in railroad signals to create the first four-way, three-color traffic light, which was installed in 1920 at the corner of Woodward and Michigan Avenues in Detroit.

Today, network administrators also are dealing with brutal traffic jams. Most enterprises face increasing capacity and performance challenges as they roll out more voice, video and cloud-based applications across their networks. These applications must be made available to a growing number of end-users, including mobile workers.

Like Potts’ traffic light, network optimization techniques such as traffic shaping can help network administrators bring some order to the chaos. Traffic shaping is the general term given to a broad range of methods designed to prioritize the movement of data over wired and wireless networks. It deals with concepts of classification, queue disciplines, enforcing policies, congestion management, QoS and fairness.

Under loaded conditions, any traffic classified as high priority — Voice over IP (VoIP) and video conferencing, for instance — gets a green light and a guaranteed level of bandwidth. The idea is to maintain high levels of performance without having to purchase additional bandwidth.

Without intentional traffic shaping, network traffic flow is subject to natural limitations. Bottlenecks can occur in the network, in an application or in low-speed links. Traffic shaping sidesteps these bottlenecks by controlling the volume and rate of traffic being sent into a network.

Traffic shaping products can be actively managed to limit traffic in several different ways. Some products can identify and categorize specific types of network traffic, constraining each particular category of traffic to use no more than a specified amount of bandwidth. Traffic shapers can categorize traffic based on macroscopic characteristics such as the traffic’s protocol, the ports an application is known to use or on the basis of connections to a well-known host.

Another route is to set per-user traffic limits to ensure that network traffic is shared fairly among all users. For instance, end-users could be limited to no more than 256Kbps, which would provide DSL-like service but would ensure that no user hogs too much of the total available network capacity at any particular time.

 In addition to setting limits on a per-application or a per-user basis, traffic shaping devices can be used to define the relative priority of different types of traffic. Many network administrators, for example, choose to limit peer-to-peer file sharing to times when higher priority applications don’t need the bandwidth.

While traffic shaping tasks can be done directly on a regular edge router, specialized plug-and-play traffic shapers allow network administrators to quickly and easily bring network traffic into balance without having to build and manage extensive policy libraries and with no changes to existing network infrastructure. These appliances often feature built-in application-level rules to dynamically control traffic based on current network usage.

Organizations experiencing poor quality VoIP calls and videoconferencing sessions can greatly improve the user experience with traffic shaping tools. Contact IPC to learn more.