Networking specialist

In the first part of this article series, I talked about some basic networking hardware such as hubs and switches. In this article, I want to continue the discussion of networking hardware by talking about one of the most important networking components; routers. Even if you are new to networking, you have probably heard of routers. Broadband Internet connections, such as those utilizing a cable modem or a DSL modem, almost always require a router. A router's job isn't to provide Internet connectivity though. A router's job is to move packets of data from one network to another. There are actually many different types of routers ranging from simple, inexpensive routers used for home Internet connectivity to the insanely expensive routers used by giant corporations. Regardless of a router’s cost or complexity, routers all work on the same basic principles. That being the case, I'm going to focus my discussion around simple, low budget routers that are typically used to c...

Troubleshooting 101 When working in a networked environment, it’s common to have to troubleshoot problems often and quickly. Not only do problems come up often, but they are normally complex, require a lot of abstract thought, involved multiple parties and can be downright confusing. The following flow chart is a quick way to visualize all the steps involved in troubleshooting just about anything: First you want to establish a baseline of normal operation. If you do not know what your router operates like normally, how will you know if it has a problem? Next, you want to document what the symptoms are and attempt to define what the problem is. If you have a runny nose, a cough and aches, you may have the flu. Make sure you gather all the facts based on the defined problem. In this section you want to consider your possibilities for defining what the problem is. If it’s the Flu, then we have to attack it with rest and medication. Make the plan, have a fallback plan in case the main pla...

In my last article, I introduced the Open System Interconnect (OSI) reference model and discussed it's first layer; the Physical Layer. In this article I will discuss the second layer, the Data Link Layer, from a hardware perspective. The data link layer provides functional and procedural methods of transferring data between two points. There are five general functions which the Data Link layer is responsible for. These functions are: * Logical Link Control * Media Access Control * Data Framing * Addressing * Error Detection Logical Link Control The Logical Link Control (LLC) is usually considered a sublayer of the Data Link layer (DLL), as opposed to a function of the DLL. This LLC sublayer is primarily concerned with multiplexing protocols to be sent over Media Access Control (MAC) sublayer. The LLC does this by splitting up the data to be sent into smaller frames and adding descriptive information to these frames, called headers. Media Access Control Like LLC...

The Open System Interconnect (OSI) reference model is a model, developed by the International Standards Organization (ISO), which describes how data from an application on one computer can be transferred to an application on another computer. The OSI reference model consists of seven conceptual layers which each specify different network functions. Each function of a network can be assigned to one, or perhaps a couple of adjacent layers, of these seven layers and is relatively independent of the other layers. This independence means that one layer does not need to be aware of what the implementation of an adjacent layer is, merely how to communicate with it. This is a major advantage of the OSI reference model and is one of the major reasons why it has become one of the most widely used architecture models for inter-computer communications. The seven layers of the OSI reference model, as shown in Figure 1, are: * Application * Presentation * Session * Transport * Ne...