The Quality of the Network

The Quality of the Network

This is the one subject that truly makes me nervous, perhaps because I have gone through the trials and tribulations of setting up and maintaining networks in my workplace. I must admit that technology has improved a great deal over the years, and the quality issue has somewhat settled in the most part, but it was not always that easy. We had to deal with all sort of inconveniences regarding; software, PC equipment, peripherals, physical network design, etc. The combination of all these factors is what ultimately determines the quality of the local area network. There is another huge element involved, which is the bandwidth available. I will cover both aspects throughout this paper, and will analyze some relevant issues regarding the importance of quality of service in general

Selection of Equipment

Quality begins with the selection of the components. These components are not only limited to hardware itself, but the software also plays an important roll in the development of quality in general. In the world of networks, cheap, does not work, no matter how hard we try, so our first order of business is to acquire some well known, top of the line equipment. For this matter, we must develop a deep sense of researching and getting to get familiar with what is out there leading the industry. Who is using what, or how effective and reliable the equipment performs, and what kind of efficiency is being provided in general; should be the dictating rules when choosing components. Where to obtain the equipment is another important factor that seems irrelevant, but as a general rule, we must stay away from those stores that advertise products at unbelievable low prices. I will not dare mentioning the name of any these stores. It would not be appropriate for ethical reasons, but if your electronic component fries within a week after you have purchased it, you must stay away from that store.

Consolidating LAN Quality

One of the most significant improvements in network hardware has been the migration from traditional hubs to switches. In essence, a hub and a switch do the same functions, but they are two different components in technological structure and performance. A switch, guarantees the QoS for higher priority traffic, provides adequate security, gives a better response time, and it prevents more collision and packet losses. Best of all, the migration is a simple, non-disruptive operation. This approach truly alleviated much of the common daily network problems. The collision and data loss issue was eliminated almost entirely. It provided the necessary confidence of a solid network performance, which delivered high quality of service. By this time, all other equipment has carefully been selected and running properly, starting with high capacity servers to provide reliability and performance throughout the entire Local Area Network. The entire premises are hard wired, except for very few areas in which wireless was a necessity. No workstations are reporting problems, meaning that that we have finally consolidated the desired quality of our local area network.

Expanding the Network

So far, we have controlled all the quality aspects of the Local Area Network. The traffic is flowing smoothly, and most of the bottleneck deficiencies have been corrected. It is now time to move on to communicate with the outside world. What can possibly go wrong from this point on? Everything. From this point on, the performance will be tightly related to the amount and efficiency that the bandwidth may provide and we will closely monitor how throughput will affect our overall Wide Area Network's developments; but to be specific, the Quality of Service, from this point on, will refer to the actual capacity of providing efficient services to selected network traffic over various technologies; for instance, streaming video, IP telephony (VoIP), Video Teleconferencing, Alarm Signaling, etc.

The importance of QoS

Quality of Service, in this day and age, totally depends on bandwidth. This does not mean that all other network factors have to be underestimated. Bandwidth and Broadband are two concepts that are barely emerging from their infancy stages. Yes, we may say that they are both robust children in the process of maturing, but they are yet, a long way, to get to adulthood. We, as IT developers, have no other choice than to take the best of both, and deal with all their mischievousness. Sometimes, they will work for us, some other times we will have to make extra efforts on our own to make things work with whatever tools we are provided.

According to the academic definition found on Wikipedia, QoS refers to the probability of the telecommunications network meeting a given traffic contract. This definition can be explained in more IT words and we may say that the reference is to the probability of a packet reaching its destination within the desired latency period. What can realistically happen to these packets when traveling across the net? They may fall in an out-of-order delivery phase, each taking different routes resulting in different delays, and then needing special protocols to rearrange. This is important for VoIP or video streaming where the quality will be affected by latency or lack of isochronicity. Common jitters and delays may affect the quality if packets take a less direct route to avoid congestion resulting in unpredictable delays. Errors or dropped packets will also cause severe delays in the overall transmission. The combination of one or more of these factors is what really undermines the QoS.

What are the techniques to achieve a desired level of QoS? We simply need to raise the priority of a flow and limit