1. Network 1 S02 By Dr Ahmad AA Alkhatib

2. Network Cabling Basics For networks to work, the computers must have the capability to take the bits sitting in RAM on one computer and somehow send a copy of those bits into RAM on the other computer. For the process to work, the computer typically asks the NIC to send the bits over the cable that is connected to the NIC. So, the NIC must be connected to some form of transmission medium over which it can send the bits to the other computer.

3. Creating a Transmission Medium Using Cables To send data—bits—to another computer, the computers can use some physical medium over which electricity can be sent. In this case, the physical medium is typically a set of copper wires because copper easily conducts electricity. Because copper wires are brittle, the wires are usually wrapped in a colored plastic coating to help prevent them from breaking. The plastic coating also helps provide some electrical insulation.

5. The term bits per second (bps) often refers to the speed of network connections. Note that the unit is bits, not bytes. In real life, LANs typically run at much higher speeds, with a slow LAN transmitting at 10 million bits per second (megabits per second, or Mbps). The section “Names for the Rate at Which a Network Sends Data” describes the speeds at which bits can be sent over a networking cable

6. Networks Basics(Cont…) Transmission Control Protocol/Internet Protocol (TCP/IP) is a set of protocols or rules developed to allow cooperating computers to share resources across a network. To enable TCP/IP on the workstation, it must be configured using the operating system tools.

7. Telecommunication Systems Consider for a moment all the different communications that take place in an organization. Some communications are face to face, but others use some type of technology. Think of email, phone calls, text messaging, viewing pages on the Internet, downloading files. All of these communications make use of a telecommunications system. A telecommunications system is a collection of nodes and links to enable telecommunication. Telecommunication is communication at a distance using electrical signals or electromagnetic waves. Examples of telecommunications systems are the telephone network, the radio broadcasting system, computer networks and the Internet. The nodes in the system are the devices we use to communicate with, such as a telephone or a computer.

8. Components of a Telecommunication System In its most fundamental forms, a telecommunication system includes a transmitter to take information and convert it to a signal, a transmission medium to carry the signal and a receiver to take the signal and convert it back into usable information. This applies to any communication system, whether it uses computers or not. Most modern day telecommunications systems are best described in terms of a network. This includes the basic elements listed above but also the infrastructure and controls needed to support the system. There are six basic components to a telecommunications network.

9. 1. Input and output devices, also referred to as 'terminals‘ These provide the starting and stopping points of all communication. A telephone is an example of a terminal. In computer networks, these devices are commonly referred to as 'nodes' and consist of computer and peripheral devices. 2. Telecommunication channels, which transmit and receive data This includes various types of cables and wireless radio frequencies. 3. Telecommunication processors, which provide a number of control and support functions For example, in many systems, data needs to be converted from analog to digital and back.

10. 4. Control software, which is responsible for controlling the functionality and activities of the network 5. Messages represent the actual data that is being transmitted In the case of a telephone network, the messages would consist of audio as well as data. 6. Protocols specify how each type of telecommunication systems handle the messages For example, GSM and 3G are protocols for mobile phone communications, and TCP/IP is a protocol for communications over the Internet.

11. Different Types of Networks There are a number of different ways to describe computer networks, including network size, transmission media, management method and network topology.

12. Network types The transmission media of a computer network describes the material substances that carry energy waves, which include the data being transferred. The two main categories are wired connections, which use physical cables, and wireless connections, which use electromagnetic waves and do not require a physical medium. The most commonly used wired connections use twisted-pair cables, coaxial cables and fiber optic cables. The most commonly used wireless connections use radio waves, microwaves and infrared waves.

13. Networks Types There are several different types of computer networks. Computer networks can be characterized by their size as well as their purpose. The size of a network can be expressed by the geographic area they occupy and the number of computers that are part of the network. Networks can cover anything from a handful of devices within a single room to millions of devices spread across the entire globe. Some of the different networks based on size are: Personal area network, or PAN Local area network, or LAN Metropolitan area network, or MAN Wide area network, or WAN

14. In terms of purpose, many networks can be considered general purpose, which means they are used for everything from sending files to a printer to accessing the Internet. Some types of networks, however, serve a very particular purpose. Some of the different networks based on their main purpose are: Storage area network, or SAN Enterprise private network, or EPN Virtual private network, or VPN Let's look at each of these in a bit more detail.

15. Personal Area Network A personal area network, or PAN, is a computer network organized around an individual person within a single building. This could be inside a small office or residence. A typical PAN would include one or more computers, telephones, peripheral devices, video game consoles and other personal entertainment devices. If multiple individuals use the same network within a residence, the network is sometimes referred to as a home area network, or HAN. In a very typical setup, a residence will have a single wired Internet connection connected to a modem. This modem then provides both wired and wireless connections for multiple devices. The network is typically managed from a single computer but can be accessed from any device.

16. This type of network provides great flexibility. For example, it allows you to: Send a document to the printer in the office upstairs while you are sitting on the couch with your laptop. Upload the photo from your cell phone to your desktop computer. Watch movies from an online streaming service to your TV. If this sounds familiar to you, you likely have a PAN in your house without having called it by its name.

17. Networks Types(Cont…) Local Area Networks (LANs) are designed to : - Operate within a limited geographical area. - Allow multi-access to high bandwidth media. - One single interface for each host (Point to multipoint). - Control the network privately under local administration (installation, troubleshooting, developing). - Provide full-time connectivity to local services. - Connect Physically adjacent devices. - All the devices must be owned by the customer.

18. A local area network, or LAN, consists of a computer network at a single site, typically an individual office building. A LAN is very useful for sharing resources, such as data storage and printers. LANs can be built with relatively inexpensive hardware, such as hubs, network adapters and Ethernet cables. The smallest LAN may only use two computers, while larger LANs can accommodate thousands of computers. A LAN typically relies mostly on wired connections for increased speed and security, but wireless connections can also be part of a LAN. High speed and relatively low cost are the defining characteristics of LANs

19. LANs are typically used for single sites where people need to share resources among themselves but not with the rest of the outside world. Think of an office building where everybody should be able to access files on a central server or be able to print a document to one or more central printers. Those tasks should be easy for everybody working in the same office, but you would not want somebody just walking outside to be able to send a document to the printer from their cell phone! If a local area network, or LAN, is entirely wireless, it is referred to as a wireless local area network, or WLAN.

20. Networks Types(Cont…) Wide Area Networks (WANs) are designed to : - Operate over wide geographical area. - Allow access over serial interfaces operating at lower speeds. - Provide full time and part time connectivity. - Connect devices separated over wide, even global areas. - There is an fee paid to the provider.

21. A wide area network, or WAN, occupies a very large area, such as an entire country or the entire world. A WAN can contain multiple smaller networks, such as LANs or MANs. The Internet is the best-known example of a public WAN.

22. MAN A metropolitan area network, or MAN, consists of a computer network across an entire city, college campus or small region. A MAN is larger than a LAN, which is typically limited to a single building or site. Depending on the configuration, this type of network can cover an area from several miles to tens of miles. A MAN is often used to connect several LANs together to form a bigger network. When this type of network is specifically designed for a college campus, it is sometimes referred to as a campus area network, or CAN.

23. Private Networks One of the benefits of networks like PAN and LAN is that they can be kept entirely private by restricting some communications to the connections within the network. This means that those communications never go over the Internet.

24. Networks Types(Cont…)