Bandwidth Management

Every afternoon after 3 P.M., it takes 40 seconds to pull up Google or CNN. Your staff has to wait until the next morning to send cataloging records to a remote branch. Video or audio downloads are out of the question. Your first response might be, “Buy more bandwidth!” and that’s not a bad idea at all, but you might not have enough money to buy more bandwidth. Moreover, some libraries are finding that patrons will fill up everything they’re given. Double your bandwidth, and a month later it’s slow again after 3 P.M. Patrons can use file­-sharing applications, such as BearShare, LimeWire and UTorrent, to download several large files simultaneously. Online games, streaming video and streaming audio can also take up large amounts of bandwidth.

There are a few related approaches to managing and controlling bandwidth.

  • You can slow down the greedy, bandwidth-­hungry programs and/or the patrons who use them.
  • You can prioritize the important, high-priority traffic on your network (e.g., catalog records or phone calls).
  • Finally, you can optimize the traffic on your network to increase efficiency and avoid redundant transmissions.

We’ll explore all three approaches.

Why Should You Manage Your Bandwidth?

  • Bandwidth equals $$$$$. Bandwidth costs thousands of dollars a month, and anything you can do to lower your bandwidth consumption will save you money in the long run.
  • Improved Internet experience. Bandwidth management can make the difference between a network that’s perceived as sluggish and unresponsive and one that seems fast and reliable. For delay-sensitive applications, such as Voice over IP, bandwidth management might make the difference between a device that works and one that’s unusable.
  • Fairness through compromise. Someone accessing a low-­bandwidth, text­-based site shouldn’t have to put up with a slow connection because someone else is downloading 5-GB movies onto their laptop. Going to the opposite extreme and blocking all video traffic or all file­-sharing traffic is also unfair because it penalizes the moderate, occasional downloader as much as it hurts the patron downloading 50 albums every afternoon. Students often use BitTorrent or streaming video to access lectures and other files related to their classes. In other words, it’s not always the particular protocol or application that’s a problem; it’s the few folks who use more than their share. Bandwidth management strikes a compromise. You can limit bandwidth usage on a per-­user basis, a per­-protocol basis or both. No single user or type of traffic can hog everything, but they won’t be completely blocked either.
  • Improved traffic prioritization. Although it’s hard to give one stream of patron traffic priority over another based on your own judgments regarding the appropriateness of the content, libraries often have valid reasons for giving some bandwidth preferential treatment. Certain voice and video applications simply won’t function if they don’t have reliable bandwidth and low latency. Also, you may decide that traffic from staff machines should have priority over patron traffic since your library depends on the effective, reliable transmission of catalog records and other files.
  • Opportunities for remote and rural libraries. Unfortunately, some parts of the country still don’t have access to high­-speed data lines, or the prices are prohibitive. In these cases, bandwidth management can make a big difference. Even if you don’t have money to spend on a high­-end commercial device, you can put some open­-source software on a desktop computer with two network cards and use that as your Web caching server or your traffic­-shaping server.

Bandwidth Management Techniques

Our Bandwidth Management Techniques — Tips and Actions tool covers four bandwidth management techniques and suggestions, hardware solutions and software solutions. As with most tools, the specialized hardware devices are usually more powerful and more expensive. If you choose a software solution, you’ll need to install it somewhere. Depending on how much work you expect the software to do, you might make do with running it alongside other programs on an existing server, or you might be able to run it on an old desktop PC.

Bear in mind:

  • These four bandwidth management techniques come in a variety of combinations and packages.
  • You might find them all in a single hardware device or a single piece of software.
  • On the other hand, you might decide to buy one device that specializes in packet shaping and another that focuses on optimization.

Bandwidth management tools usually reside on the edge of your network and filter all the traffic leaving and entering your network. However, you can also shape the traffic on a particular server or a particular segment of your network. Choosing the right bandwidth management strategy depends on the type of traffic your network typically carries. Therefore, it helps to monitor your bandwidth and pay attention to patterns (e.g., which protocols are taking up the most space).

Even after you’ve looked at the traffic patterns on your network, you should take your graphs to a network administrator or a networking consultant.

Stories from the Field

Right now, we have a packet shaper from Symphonics, but we’re gonna have to do away with that, because at the time we purchased it, we were expecting that we’d have 3-Mbps of connectivity. Now because [of] our access to the municipal fiber, we’re up to a 100-Mbps connection, and it’s not able to handle that much traffic. So we’re gonna have to do away with that. But we did recently upgrade all of our locations to SonicWALL appliances and that does have some bandwidth management built into it. I don’t think it’s as good as the Symphonics box, but it has some capability. Basically, a traffic shaper is just a traffic cop and you tell it what’s most important in terms of traffic. Is it the library catalog traffic that’s going out to the branches? Is it the people sitting at home trying to connect to your OPAC server or your Web site? Is it the staff browsing the Internet? And you give it a set of priorities and rules, and it just says, ‘Okay, well, there’s too much video­-streaming bandwidth being used. You need to wait, and I’m gonna let this library catalog traffic go through.’ And then, once library catalog traffic goes through and there’s a little bandwidth freed up, then the Internet computer users can start seeing their streaming traffic again. But we’ve kind of put [a] priority on the actual business of operating the region as the number one priority for who gets the bandwidth.

When I look at our package shaper, the number one source of traffic is HTTP traffic. But HTTP traffic has been used for so many different things. For instance, you can stream video over HTTP. So it’s hard to determine exactly where that’s all going, but that’s the number one use of bandwidth. When you start going beyond just looking at the protocol information, you almost start getting to the point where you’re doing content filtering or content prioritization. And the device we have does not do that. It’s my understanding that there are devices that can go beyond just the protocol level and actually look inside the packet and see, ‘Well, it says it’s HTTP but I can tell that it’s really video traffic, so they can throttle it back.’

Jay Roos
Great River Regional Library, MN

The only problem with bandwidth is you put it in and it’s going to get filled up, especially if they’re doing YouTube and some of the higher-­bandwidth types of things. Now there are some devices that will throttle bandwidth for you. We’re part of the CleveNet Consortium. They handle all of our network connectivity for us. I know they’re working with Cisco to get an appliance that will do some bandwidth throttling and do a little throttling with our wireless networks, because honestly, one of the biggest hogs is the public wireless network — people coming in with their own laptops. Because they have LimeWire and BearShare and all the file sharing and BitTorrent types of things on their laptops, and they’re able to do that over HTTP, because it doesn’t use some other weird port. So there’s no good way to stop that. Some of the stuff you don’t want to stop. I mean, you don’t really want to block YouTube. We don’t really want to block a whole lot of anything generally. But how do you throttle that bandwidth and keep those people from completely killing all your bandwidth? So I know they’re working on some appliances that are going to help with that.

Jim Haprian
Medina County Library District, OH

One thing I notice is that the more bandwidth you give, the more it’s going to be used. I have a lot of my remote sites that are running two, three T1s and they’re still maxed out. A year ago, they were on just a T1 connection and they were fine. But guess what? It started running slow and I said okay, I’ll bump it up. So I took them up to three T1s and they’re still slow today because I give more bandwidth, and the more bandwidth you give, the more it is being used because I’m not doing any bandwidth shaping, [which is] something now that I’m looking at getting into. I know that with the budget shrinking, it’s going to be hard for me to go and say okay, a couple of years ago I was at 6 Mbps and today I have a 23-Mbps pipe, and I want actually more money to upgrade it. They’re probably going to look at me and say no way, with budgets shrinking. So what I’m trying to do now is I’m looking really closely at my bandwidth and the kinds of traffic, and I’m going to try to start doing bandwidth prioritization and things like that so that I can give more bandwidth to things that we consider core library services.

Monique Sendze
Johnson County Library, KS

One of the things that we looked at — we just went to 6 Mbps here at the main library, and they have this MetroNet, I think it’s called MetroNet or something BellSouth has, and it’s supposed to be like 10 Mbps for each branch and then it’s burstable to 100 Mbps based on your usage. That way, if all of a sudden you have a lot of usage, it can go up if it needs to, but it won’t unless it has to. We have experienced some bandwidth issues at some of our branches, and when you’ve got a T-1 at each one, you would think you’d be okay, but I'm telling you, with the downloads and the bandwidth it eats up, you have to go back and think, ‘Well, do I need to manage this?’ Should you buy the device to manage the bandwidth to say I’m only going to give 5 percent here and 5 percent there? Or do we increase the bandwidth, which is going to cost the library system more?

Delbert Terry
Bossier Parish Libraries, LA

Further Resources

Looking for more information about bandwidth management for your library? If so, check out the Further Resources section.