How to monitor and avoid network bottlenecks

What is a network bottleneck?

A network bottleneck is a delay in data transmission or data transfer through a computer network. Delays occur when a system’s power is overloaded by the amount of information and/or data that it is required to process. Bottlenecks slow the flow of data across the network. Since the first computer networks were designed to transmit text files, the TCP/IP protocol that computers use to communicate with one another over a network is designed for smaller files. High density graphics files and other rich media transferred over the web can severely tax the bandwidth capabilities of networking protocols and computer systems that utilize them, which can lead to slowdowns or crashes.

Network bottlenecks slow communications and can lead to serious crashes and downtime. Although some systems today are designed to continue to function even after maximum capacity has been reached, the bottleneck is still in effect since not all the data the system is attempting to transfer or process is being handled.

Bottlenecks can be subdivided into two categories:

Short-term bottlenecks – Short-term bottlenecks are caused by temporary problems such as hardware failures or software glitches than can be easily corrected or repaired. Short-term bottlenecks can be identified and rectified without further consideration, because once the problem is repaired and the bottleneck is remedied it will no longer exist.

Long-term bottlenecks – These are reoccurring bottlenecks that can primarily be blamed on a lack of resources or proper equipment. Examples of long-term bottlenecks would be a preponderance of inefficient or slow hardware, or an archaic network or broadband connection that prevents traffic from being consistently routed through the network.

How to identify a network bottleneck:

Bottlenecks can occur due to some of the following causes. Please note that this is not a complete list of possible bottleneck areas, just some suggestions:

Cable – Bad cables can destroy a network. Most modern networks run at 100Mpbs or 1000Mpbs, so it’s extremely important to ensure that all cables are working effectively. If a cable is crossed with a high-voltage power line, the power line can actually degrade the signal of the cable and cause a network outage or bandwidth bottleneck. Also, since many network cable installs are done with self-made cables (cut and crimped by networking professionals) it’s common for these connections to fray and falter.
Network interface – One PC with a bad network adapter can degrade the signal of the entire network.

Defective RAM – Since networking occurs in real-time, systems that handle networks are often RAM-intensive devices. Defective or improperly installed RAM memory can lead to networking bottlenecks when the system in question can’t handle the entire throughput of the network due to low memory accessibility.

Software issues – Sometimes server software has glitches or defective code. Other times, exploits can be found by hackers which provide access into systems that can heavily utilize network resources. A good example of this is when a compromised system is used for DDoS (Distributed Denial of Service) attacks. A DDoS attack is when many systems are used to simultaneously send commands to a remote server. If a compromised system is used for a DDoS attack, much or all of its bandwidth might be utilized by the attackers, creating a catastrophic bottleneck.
The other side of the coin is that a a DDoS attack can be used to create a bottleneck when targeted at a specific system. When commands from many thousands or hundreds of thousands of systems are sent to the same address, it can cause a catastrophic network overload which destroys the utility of the system. Even a small DDoS attack can cripple medium-sized networks, especially without firewalls or other tools.

Now that we understand what bottlenecks are, what kind of bottlenecks exist, and how they can affect system performance, we’ll try to understand how to combat them and remedy the bottleneck issue. In order to remedy the bottleneck issue, we’ll first have to identify it. Many network tools exist which can help identify bottlenecks. These tools can help determine exactly what device or process is causing the bottleneck.

How to troubleshoot these bottlenecks:

There are many software tools that allow systems administrators to identify network bottlenecks. Once the bottleneck is identified, it can be repaired. Most major systems distributors have network bottleneck diagnostic tools built in, but there are also proprietary systems by third-party publishers specifically designed to diagnose network bottlenecks, create workarounds, and create repairs.

It is important to constantly monitor networks for bottlenecks, especially work-critical networks. Diagnostic tools can constantly run tests and identify where networks are running at less-than-peak efficiency.

Network Bottlenecks Concluded

Although network bottlenecks can cause catastrophic general network failure, it is important to remember that monitoring tools and proactive preventative maintenance can prevent these issues. Wiring should be periodically checked, computers taken off-line and tested, and diagnostic tools run on networks, especially sensitive networks that see heavy use. With the right combination of preventative maintenance and diagnostics, as well as proactive detection, most network bottlenecks can be addressed before they cause major systems failure or collapse.