Troubleshooting Wisdom

Diagnosing Bandwidth Saturation

When computer networks are pushed beyond their capacity, performance slows for all connected parties. This common issue is called bandwidth saturation. It appears in many forms, but once it's identified, there are several ways to avoid the problem.

Bandwidth measures the amount of information a network can transmit in a given time. When networks attempt to exceed their capacity, bandwidth saturation occurs. The problem manifests itself in both home and internet provider networks.

Determining whether saturation is related to home our outside networks is critical because you'll take a different solution path depending on where the problem originates. At home, the most common cause is too many people/devices using the network at once. Bandwidth saturation on an internet provider's network is similar but is a result of an ISP routing too much traffic through the same infrastructure.

Identifying the Problem

Periods of high latency often indicate bandwidth saturation. If latency spikes correlate with events like uploading large files or several people using the network at once, the problem is probably related to your home network. Latency spikes are visualized clearly by PingPlotter, and a few examples are available in the PingPlotter manual.

When you have a hard time associating periods of poor network performance with network overuse in your home, you could be dealing with an internet provider related problem. To diagnose provider related bandwidth saturation, look for situations where performance looks good until a certain hop and bad through the remaining hops. This Pingman Knowledge Base article contains more information about identifying patters like this.

This tutorial shows how bandwidth saturation manifests in PingPlotter and illustrates some of the thought process behind pinpointing network problems.

Avoiding the Problem

When you find bandwidth saturation occurring on your home network, limiting usage is the easiest approach to avoiding the problem. If managing people's network operations is not ideal, internet service providers are always happy to sell you more bandwidth.

An alternative to buying more bandwidth involves a device that gives preference to certain types of data. Configuring networks to treat certain data differently is known as Quality of Service (QoS). The option is more technical, but might be the best solution if limiting usage and buying more bandwidth are off the table.

If you're experiencing ISP related bandwidth saturation, you aren't in a position to limit usage of other customers or implement QoS. Because of your position, solving the problem requires interactions with tech support.

Calling tech support is a daunting task. We wouldn't wish the situation on our worst enemies, but if you do find yourself contemplating a tech support call, our Step-by-Step Troubleshooting Guide offers advice on building a case that proves a problem and working with support in a way that gets results. Be sure to give the guide a look before embarking on your quest.

What if it's Not Bandwidth Saturation?

Bandwidth saturation is one of many common network problems. If you're experiencing network problems, but your analysis does not look like bandwidth saturation, check out our lineup of other usual suspects. The article provides examples you can match against your collected data to properly diagnose your problem.