The Fundamentals of Navigating Computer Networks: LIBRARIANS, EMPOWERED WITH AN UNDERSTANDING OF NETWORK SYSTEMS, ARE ABLE TO UNLEASH THE POWER OF ELECTRONIC INFORMATION.
The computer revolution has been an information revolution. Computer networks catapult ideas at the speed of electrons. They exchange files across the globe, giving users instant access to information. But networks are not magic. They are made up of computers interacting with one another over a series of cables, switches, routers, and servers. Protocols have been established so that computers can communicate effectively with one another.
The World Wide Web is a dominant service linking PCs, laptops, smartphones, and game consoles into a global network. A PC in an office in New York City can interact with a server in Seattle. A shopper in Ohio can buy a book from a store in the U.K. from the comfort of her home. A librarian can retrieve a scholarly article on Julius Caesar using an electronic database, a file retrieved from a distant server.
Modems, Routers, and Servers
How do computer networks work? How does a web browser display a webpage? The internet, like a 19th-century telegraph service, is ultimately based on cables. Even wireless networks depend on wired connections.
Remember dial-up? Pre-existing phone networks were a ready fit for the internet, as phone companies had already established the infrastructure for long-distance communication. While current network connections use twisted-pair cables or fiber optics, that old-fashioned RJ-11 phone jack plays a critical role in the modern computer network. For the sake of demonstration, we will focus on the common RJ-11 (plain old telephone) and RJ-45 (twisted-pair Ethernet) cables (Figure 1).
Let us look at a very simple home connection. A business woman checks her favorite news website on her home PC. The PC has an Ethernet cable (in this case, an RJ-45 cable) that streams data into a modem/router device behind the computer. The modem/router device is where old technology meets the new. The modem translates the digital signal into an analog signal. The analog signal is passed on to the phone company. This process is why a regular phone cord comes out of the back end of a modem and leads into the phone jack in the wall. The phone company takes care of the signal, sending the user request far and wide. If this user has her internet service from a cable company, a cable line instead of a phone line would come out of the back end of the modem.
But what about the router? It routes data between different networks. Routers and modems were conventionally two different devices because they do different things. However, in smaller networks, these two devices are now often combined into one box, the modem/router. The user's request is sent to the home modem/router, where it is routed out of the home network into a wider network, and its signal is converted from digital to analog so that it can pass through the phone or cable infrastructure.
When the businesswoman sends her request for the news website, the signal is sent out and routed across town, across the state, across the country, and sometimes across the world until it reaches its destination, often a server holding many HTML files. Believe it or not, underwater cables route internet requests across the ocean in the event that a request needs to access a server on the other side of the globe. Alternatively, a satellite service can bring the internet to remote locations in places that have not been cabled. However, the advantage of cables over satellites is that earthbound wires are not burdened to transmit data across astronomical distances.
Networks Big and Small
Networks come in all shapes and sizes. The potential to share data between machines hatched with the birth of electronics. In an era of horses and wagons, Samuel Morse (of Morse code fame) envisioned wires transporting signals across great distances. Before the proliferation of the internet, PC data was physically transferred from one machine to another by a floppy disk over a "sneakernet," a network in which data traveled by way of sneaker shoes. Today, however, it is assumed that new machines have the ability to talk to each other and share data through standard internet protocols.
Residential and small office networks are called SOHO (small office/home office) networks. These common network structures connect the devices in a house or a small business to the internet. For instance, say a small business has four computers, and they have RJ-45 cables connecting to a single network device. This SOHO network device plays three roles in this scenario. First, it links all the computers into a wired network, so it functions as a switch (Figure 2). Second, it routes the small business network to the wider internet, so it functions as a router. Third, because it translates the users' digital signals into analog signals so the data can be transmitted over telephone cables, it functions as a modem. In this example, the SOHO device acts as a switch/router/ modem, a convenient technology for small networks.
Now let's go bigger. A community library has, say, 12 public access computers for patrons and eight computers for staff, all of which are physically wired by RJ-45 cables. In addition, three laptops are available for patrons to connect to a wireless network. Patrons can also access the library's wireless network. How does all of this function? To start, this network is too large for a SOHO device. All of the patron and staff computers with physical cables will plug the RJ-45 cables into the wall, from which the cables will then lead--in this case-into a basement or closet (Figure 3) where they connect into a large panel. From this panel, those wired connections are bound into the router device. That explains the wired connections, but what about the wireless connections? The laptops will communicate with the network through an access point (Figure 4). The access point is a device that transmits wireless radio waves so wireless devices can connect into the network. The RJ-45 cables from the computers and the access points all feed back into the panel in the basement. The panel then connects to the router and the modem, from which data packets are sent out to the wider world and received. Thus, wireless networks ultimately require a physical connection.
Networking in the Cloud
Cloud computing has gained favor among many companies and individuals. With cloud computing, users can access applications and data by simply logging into an account from any device with an internet connection. The cloud offers great advantages and some disadvantages.
What are the advantages? It is simply convenient. Whether users are in an office, at home, or on the beach, they can access their data from a cellphone, laptop, tablet, or other device as long as it has an internet connection. For instance, students can access the same email account from the PC in their dorm or from their cellphone in the cafeteria. Users are no longer dependent on data being stored on a local hard drive. Employees can all make changes to the same document on a cloud service. With cloud computing, users no longer need to be at a work computer to get their data. All they need is a username and password. In addition, solid cloud providers often back up user data on multiple servers.
So what are the potential disadvantages of the cloud? Just like with everything else that is available online, there are security issues associated with it. First of all, "cloud" is somewhat of a misnomer. It gives the impression that it is exists on an ethereal, misty plane. However, an online document stored on the cloud does not exist in the air, but on the hard drive of a server in an undisclosed location. Thus, when a businessman creates and saves a spreadsheet with a cloud service, the file exists on a very 3D hard drive that sits on a server in a remote location--not his own computer. In addition, usernames and passwords can get into the wrong hands, at which point the accessibility of the cloud becomes a liability. Another issue relates to data ownership. Sensitive information--including credit card numbers, bank account numbers, and Social Security numbers--should be handled delicately in a cloud environment. Data on the cloud is just a username and password away for both legitimate users and fraudsters.
Common Network Issues
Networks can only operate if all the pieces of the chain are working. Depending on where an issue arises on this chain, network outages can affect one person, one office, one building, one campus, or (in the case of a major power outage) a whole metropolitan area. Some of these problems can be managed by a user. Others require a certified network technician, engineer, or electrician. Always have a network technician or other certified person handle important network issues.
Issue one--The wired connection is working, but the wireless connection is not. Let's start with what we know. Because the wired connections are working, we know that the problem is not with the modem or router. We likely have an issue with the wireless access point, as no wireless device can connect to the network. Have a technician ensure that the wireless access point is working.
Issue two--All wired and wireless connections are working, except for those for a small group of wired computers at the same table. Here is the good news: The infrastructure of the network is strong. Most of the wired computers are working, meaning that the issue is isolated to a small group of computers. Another good sign is that the wireless access point is working. It's likely that the computers at the one table share the same small switch. And that small network switch is probably sitting on or under that table. If the small switch has no blinking lights, it may have been unplugged. If it's plugged in and no lights are blinking, contact a technician.
Issue three--The wired and the wireless connections are down. Nothing works. Since everything is down, it sounds like there may be an issue with the modem/router or with a server computer. Notify a technician. Sometimes the modem/ router simply needs to be powered off and powered on, but other times there is a hardware issue with the modem/router or network server that needs to be addressed by a technician.
Healthy Library Networks
Libraries rely on computer networks. Like all 21st-century institutions, they need access to the instantaneous information exchange that computer networks allow. In addition, libraries rely on strong networks that connect patrons to the articles, books, and the online resources that have enhanced information services. Librarians, empowered with an understanding of network systems, are able to unleash the power of electronic information.
Dulaney, Emmett. CompTIA Network+ N10-006 Exam Cram, Fifth Edition. Indianapolis: Pearson Education, 2015.
Ross, John. Network Know-How: An Essential Guide for the Accidental Admin. San Francisco: No Starch Press, 2009.
Jeffrey Meyer is the director of the Mount Pleasant Public Library in Iowa. He received his M.L.S. from the University of Pittsburgh, and he holds CompTIA A+ computer certification. Contact him at jeffreythelibrarianfagmail.com
Caption: Figure 1: Two common but different cables in wired network systems, the RJ-45 cable (top) and the RJ-11 cable (bottom)
Caption: Figure 2: An RJ-45 cable connects into a small switch
Caption: Figure 3: Lines of RJ-45 cables pass through a wall, leading from the user computers on the main level down into the modem and router room.
Caption: Figure 4: A wireless access point transmits radio waves that allow users to connect to the wireless network.
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|Publication:||Computers in Libraries|
|Date:||Mar 1, 2019|
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