What is Traffic Shaping?

What is Traffic Shaping?

When you’ve worked in networking for a while, you’ll come to realize an unspoken truth. There’s never enough bandwidth to go around. A lot of professional network design is really a matter of figuring out how to split your resources in order to minimize problems.

When it comes to rationing bandwidth, you have a few different philosophies, but one of your most dynamic and responsive tools is traffic shaping. It can help the most important functions on your network flow smoothly without increasing your bandwidth or hardware capabilities at all.

Traffic Shaping in a Nutshell

In a general sense, traffic shaping is a technique that helps you control bandwidth and the flow of data through a network. Used correctly, it’s an optimization tool that helps everything run smoother, especially when you are pressed against the limits of your network’s bandwidth.

This optimization comes from strategically delaying the transfer of packets in order to follow preset priorities, and by utilizing those strategic delays, you can ensure higher quality connections for the most important traffic on your network.

How Traffic Shaping Works

Mechanically, traffic shaping boils down to delaying packets. The entire goal is to delay lower-priority data in order to temporarily increase bandwidth for priority data. It creates temporary bandwidth boosts when and where you need them, and when demand drops, the network can catch up on the low-priority stuff.

Clearly, this represents an optimization math problem, and for it to all work well, you have to get your definitions right. When you do, you have a dynamic, responsive system that directs traffic according to the ebb and flow of demand.

At the heart of the whole system is categorization. You have to create the right categories for your traffic in order for the shaping algorithm to succeed. Some examples of categories include telecom traffic, financial traffic, specific web applications, or even specific routes through the network. With your categories set, you can create your hierarchy of priorities, and the shaping algorithm can do the math. Here’s an example.

Say you have a gym website where people can watch instructional videos, have discussions on your website’s forum, or sign up for a membership. From a business perspective, signing up for memberships might be the most important traffic, so you put it at the top of your priority list.

If your website is getting a lot of traffic at once, your traffic shaping might slow down video requests or delay forum posting in order to prioritize transactions. Once the transactions clear up and don’t need as much bandwidth, that bandwidth is redirected to the requests that were delayed.

Put another way, you’re creating trade-offs that create the best possible experience where you want it the most at the cost of small delays in other areas.

How You Can Implement Traffic Shaping

Now that the concept is clearer, how do you actually apply a traffic-shaping algorithm to your network? It all happens in routing.

You can get a router that is capable of traffic shaping. Once you do, you can use your controlling interface to configure shaping protocols. The router will follow those protocols, and your shaping will take care of itself from there.

What this means is that you need to figure out how to categorize your data in order to configure the router in the first place. That’s the most important and challenging component. When you successfully determine your categories (and of course order them in a hierarchy), providing that information to the router typically requires terminal-level inputs. This is not a drag-and-drop GUI project. You’ll need to input your categories and hierarchy into the policy map.

Once you do, the router will have the information it needs, and it can do the rest. If you ever want to change your traffic shaping, you’ll need to edit your policy inputs.

With that, you have customized traffic shaping, and your network can benefit from it.

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