Installing network cables, whether copper or fiber-optic, can be dangerous. Often, cables must be pulled through ceilings and walls where there are obstacles or toxic materials. You should wear clothing such as long pants, a long-sleeved shirt, sturdy shoes that cover your feet, and gloves to protect you from those toxic materials. Most importantly, wear safety glasses. If possible, ask building management, or someone responsible for the building, if there are any dangerous materials or obstacles that you need to be aware of before entering the ceiling area.

· Read the labels on the ladder, and follow any safety instructions written on it.

· Never stand on the top rung of the ladder. You could easily lose your balance and fall.

· Make sure that people in the area know you will be working there.

· Cordon off the area with caution tape or safety cones.

· When you are using a ladder that leans up against a wall, follow the instructions written on the ladder, and have someone hold the ladder to help keep it steady.

The tools required to install copper and fiber-optic cable may cause danger through improper use. When working with cables, strictly follow these safety rules:

· Make sure that the tools you are using are in good working condition.

· Watch what you are doing, and take your time. Make sure that you do not cut yourself or place anyone in danger.

· Always wear safety glasses when cutting, stripping, or splicing cables of any kind. Tiny fragments can injure your eyes.

· Wear gloves whenever possible, and dispose any waste properly.

Use common sense when installing cables and fixing network problems. Call for assistance for tasks that you cannot do on your own.

Fiber-optic cables are useful for communications, but they have certain hazards:

· Dangerous chemicals

· Tools with sharp edges

· Light which you cannot see that can burn your eyes

· Glass shards produced by cutting fiber-optic cable that can cause bodily harm Specific types of tools and chemicals are used when working with fiber-optic cable. These materials must be handled with care

       The solvents and glues used with fiber optics are dangerous. You should handle them with extreme care. Read the instructions on the label, and follow them carefully. Also, read the material safety data sheet (MSDS) that accompanies the chemicals to know how to treat someone in case of emergency.

  When working with any tool, safety should always be your first priority. Any compromise in safety could result in serious injury or even death. The tools used for working with fiber optics have sharp cutting surfaces that are used to scribe glass. Other tools pinch cables with high pressure to fasten connectors to them. These tools can produce shards of glass that can splinter and fly into the air. You must avoid getting them on your skin and in your mouth or eyes.

       The process of cutting and trimming the strands of fiber-optic cables can produce tiny fragments of glass or plastic that can penetrate your eyes or skin and cause severe irritation. The fibers can be extremely difficult to see on your skin because they are clear and small. When you work with fiber-optic cabling, the working surface should be a dark mat so that you can see the tiny glass or plastic fragments. The mat should also be resistant to chemical spills.

       You should keep the work area clean and neat. Never pick up fiberoptic fragments with your fingers. Use tape to pick up small fragments, and dispose them off properly. Use a disposable container, such as a plastic bottle with a screw-on lid, to store fiber fragments. Close the lid tightly before disposing the container.

        Protect your eyes from the harmful light that may be in the fiber-optic strands. The light is a color that humans cannot see. It can damage your eyes before you can feel it. When you use a magnifier to inspect fiber-optic cable and connectors, the light emitted from the fiber could be directed into your eyes. When working with fiber, be sure to disconnect the light source. Use special detectors to help you tell if a fiber is energized.

       To make data transmission more extensible and efficient than a simple peer-to-peer network, network designers use specialized network devices such as hubs, switches, routers, and wireless access points to send data between devices. You have already discussed in your Grade 9 CHS class the different devices used in networking and which provides you the knowledge on the common networking cables that are essential in putting up a network.

      Until recently, cables were the only medium used to connect devices on networks. A wide variety of networking cables are available. Coaxial and twisted-pair cables use copper to transmit data. Fiber-optic cables use glass or plastic to transmit data. These cables differ in bandwidth, size, and cost. You need to know what type of cable to use based on the job requirements. You also need to be able to troubleshoot and repair problems along the way.

        Cable Ethernet cabling has been the standard in networking installation for years. It is the fastest way of connecting PC to a peer or to your router or a central switch. This section of the module will bring you back to the procedures in creating an Ethernet cable specifically straight-through and cross-over. Try to recall the procedures as you go on with the lesson.

        Fabricating an Ethernet Cross-over and Straight-through Cable

       In an Ethernet networking environment – like in a home or an office with multiple PCs that are wired – the computers need to be connected to a central router to allow data transfer. The router takes all the bits being sent out by the computers and relays them onto the other devices on the network.

      The straight-through Ethernet cable is used in local area network to connect a PC to a network hub and router. This is the standard cable used for almost all purposes.

       A cross-over cable, on the other hand, can be used to connect two network devices directly, without the need for a router in the middle. It simply reverses some of the pins so that the output on one computer is being sent to the input of another.

       Bear in mind that safety precautions must always be applied and observed during the fabrication of the said cables. Also, materials and tools to be used must always be complete and functional to save time, money and effort.

The following items are the materials and tools used for making Ethernet cables:

• Ethernet Cable Category 5e or Cat5e- standard wire for cabling;

• RJ45 crimp able connectors for Cat5e;

• RJ45 Crimping tool;

• Wire cutter, stripper or pliers; and

• Ethernet cable tester.

      A protocol is a set of rules. A letter sent through the postal system also uses protocols. Part of the protocol specifies where on the envelope the delivery address needs to be written. If the delivery address is written in the wrong place, the letter cannot be delivered. Internet protocol works in a similar way. Internet protocols are sets of rules governing communication within and between computers on a network. Protocol specifications define the format of the messages to be exchanged.

        Timing is crucial to network operation. Protocols require messages to arrive within a certain amount of time so that computers do not wait indefinitely for messages that may have been lost. Therefore, systems maintain one or more times during transmission of data. Protocols also initiate alternative actions if the network does not meet the timing rules. Many protocols consist of a suite of other protocols that are stacked in layers. These layers depend on the operation of the other layers in the suite to function properly.

         An IP address is a number that is used to identify a device on the network. Each device on a network must have a unique IP address to communicate with other network devices. Network devices are those that move data across the network, including hubs, switches, and routers. On a LAN, each host (device that sends or receives information on the network) and network device must have an IP address within the same network to be able to communicate with each other.

          A person’s name and fingerprints usually do not change. They provide a label or address for the person’s physical aspect—the body. A person’s mailing address, on the other hand, relates to where the person lives or picks up mail. This address can change. On a host, the Media Access Control (MAC) address is assigned to the host Network Interface Card (NIC) and is known as the physical address. The physical address remains the same regardless of where the host is placed on the network in the same way that fingerprints remain with someone regardless of where he or she goes.

          An IP address consists of a series of 32 binary bits (1s and 0s). It is very difficult for humans to read a binary IP address. For this reason, the 32 bits are grouped into four 8-bit bytes called octets. An IP address, even in this grouped format, is hard for humans to read, write, and remember. Therefore, each octet is presented as its decimal value, separated by a decimal point or period. This format is called dotted-decimal notation. When a host is configured with an IP address, it is entered as a dotted-decimal number, such as 192.168.1.5.

The subnet mask indicates the network portion of an IP address. Like the IP address, the subnet mask is a dotted-decimal number. Usually all hosts within a LAN use the same subnet mask. Table 3 shows default subnet masks for usable IP addresses that are mapped to the first three classes of IP addresses:

· 255.0.0.0: Class A, which indicates that the first octet of the IP address is the network portion

· 255.255.0.0: Class B, which indicates that the first two octets of the IP address are the network portion

· 255.255.255.0: Class C, which indicates that the first three octets of the IP address are the network portion.

In a home network with several computers and devices, it is ideal to assign each of them a specific address. This is for the purpose of avoiding problems when you do troubleshooting which requires figuring out the IP address of each of them. It is also a means to prevent address conflicts between the devices. You can also manage them with ease if you have assigned their own addresses.

Here are the procedures in assigning an IP Address on a windows base computer system:

1. Open the Control Panel’s Network Connections icon.

2. Open the icon representing your computer’s network connection.

3. Click the Properties button in the Status dialog box.

4. From the list of items, choose Internet Protocol (TCP/IP).

If more than a few computers comprise the LAN, manually configuring IP addresses for every host on the network can be time-consuming and prone to errors. In this case, using a Dynamic Host Configuration Protocol (DHCP) server would automatically assign IP addresses and greatly simplify the addressing process.

          A software utility used to dynamically assign IP addresses to network devices. This dynamic process eliminates the need to manually assign IP addresses. A DHCP server can be set up and the hosts can be configured to automatically obtain an IP address. When a computer is set to obtain an IP address automatically, the other entire IP addressing configuration boxes are dimmed or disabled. The server maintains a list of IP addresses to assign, and it manages the process so that every device on the network receives a unique IP address. Each address is held for a predetermined amount of time. When the time expires, the DHCP server can use this address for any computer that joins the network.

       The ping is a Command Prompt command used to test the ability of the source computer to reach a specified destination computer. The ping command is usually used as a simple way to verify that a computer can communicate over the network with another computer or network device.

        The ping command operates by sending Internet Control Message Protocol (ICMP) Echo Request messages to the destination computer and waiting for a response. How many of those responses are returned, and how long it takes for them to return, are the two major pieces of information that the ping command provides.

       Ping is one of your most important tools in troubleshooting Internet problems. It shows you whether the Domain Name Server is working, whether the computer you are trying to talk to is reachable, and how long it takes to get there. It does this at a very low level — only the most basic Internet functions have to be up and running.

1) Click on Start Button, then type cmd (command prompt) on the search box.

2) A black screen will appear as shown in the figure below.

3) Type ping followed by the IP address you desire to verify. The figure below shows the screen of the ping command and its output.

• Decoding names to network addresses — A domain name server (DNS) resolves machine names to numeric addresses. A single machine can have many names, all of which resolve to the same Internet address. In the example just given, the name www.google.com resolves to the Internet address 122.2.152.23.

• Round-trip response time — The parts of the replies that say things like time=105ms show you how long it took from the time the client machine sent out the ping message until a reply came back (1 ms is 1 millisecond, or one thousandth of a second). The variability in the times you see reflects that networks do not always respond identically. Differing amounts of traffic on the communication lines or differing loads on the server are common causes. You will see very different response times depending on the access equipment you use.

• Routing hop count — The part of the replies that says TTL=50 tells you about the route the message took from one point to another. The acronym TTL stands for Time to Live, which is a measure of how many rerouting from one point to another the packet has to go through before IP declares it undeliverable. The number following TTL (called the hop count) is a number that usually starts at 255 and counts down by one every time the message gets rerouted through an intermediary computer.