CMPN 375 COMPUTER NETWORKING II

1. CMPN 375COMPUTER NETWORKING II Lecture 1.1 Network Basics (Review) Lecturer: S. Phagoo

2. Outline • What is a computer network? • Types of Networks • Area networks • Network Topology • Network Protocols • Wired Vs Wireless Networking • Network Transmission Media • Measurement of Networks

3. What is a computer network? • In the world of computers, networking is the practice of linking two or more computing devices together for the purpose of sharing data and resources. Networks are built with a mix of computer hardware and computer software.

4. Types of network • Peer-to-peer Networks • Every computer can communicate directly with every other computer • By default, no computer has more authority than another • Every computer is capable of sending and receiving information to and from every other computer

5. Example of Peer to Peer Network

6. Types of Networks (Cont’d) • Client/Server Networks • Server: central computer used to facilitate communication and resource sharing between other computers on the network (called clients) • Client/server network: uses a server to enable clients to share data, data storage space, and devices • To function as a server, a computer must be running a network operating system (NOS) • Most of the concepts on the Network+ exam pertain to client/server networks

7. Example of Client Server Network

8. Types of Networks Cont’d • Wireless Networks • utilize radio waves and/or microwaves to maintain communication channels between computers. • Wireless networking is a more modern alternative to wired networking that relies on copper and/or fiber optic cabling between network devices.

9. A wireless network offers advantages and disadvantages compared to a wired network. • Advantages of wireless include mobility and elimination of unsightly cables. • Disadvantages of wireless include the potential for radio interference due to weather, other wireless devices, or obstructions like walls.

11. Area Networks • Networks can be categorized in several different ways. One approach defines the type of network according to the geographic area it spans. • Local area networks (LANs), for example, typically reach across a single home/building • Wide area networks (WANs), reach across cities, states, or even across the world. The Internet is the world's largest public WAN.

13. Network Topology • A network topology represents its layout or structure from the point of view of data flow. • Bus networks, for example, all of the computers share and communicate across one common conduit • Star network, all data flows through one centralized device. • Common types of network topologies include bus, ring, star and mesh.

15. Network Protocols • In networking, the communication language used by computer devices is called the protocol. • Computer networks may be identified by the set of protocols they support. • Networks often employ multiple protocols to support specific applications. • Popular protocols include TCP/IP, the most common protocol found on the Internet and in home networks.

16. Networking Hardware • Networking hardware includes all computers, peripherals, interface cards and other equipment needed to perform data-processing and communications within the network.

17. Network Interface Cards • The network interface card (NIC) provides the physical connection between the network and the computer workstation.

18. Transmission Media

19. Ethernet Hubs • An Ethernet hub or concentrator is a device for connecting multiple twisted pair or fiber optic Ethernet devices together, making them act as a single segment.

20. Ethernet Switch • A network switch is a computer networking device that connects network segments.

21. Routers • A router is a device that determines the proper path for data to travel between different networks, and forwards data packets to the next device along this path

22. Measurement of Networks • The performance or "speed" of a computer network is normally measured in units of bits per second (bps). • This quantity can represent either an actual data rate or a theoretical limit to available network bandwidth.

23. Modern networks support very large numbers of bits per second. Instead of quoting 10,000 bps or 100,000 bps, networkers normally express these quantities in terms of larger quantities like "kilobits," "megabits," and "gigabits."

24. The following equations define the mathematics behind these terms: • 1 Kbps = 1 kbps = 1 kilobit per second = 1,000 bits per second • 1 Mbps = 1,000 Kbps • 1 Gbps = 1,000 Mbps • In networking, both "kbps" with a lowercase 'k' and "Kbps" with an uppercase 'K' can be used interchangeably.

25. Technically, network speed can also be expressed in units of bytes per second, abbreviated as "Bps" with a capital 'B'. Use of these quantities is discouraged in networking to avoid confusion with the bits per second standard:

26. 1 KBps = 1 kBps = 1 kilobyte per second = 8,000 bits per second • The conventions used for measuring the capacity of computer disks and memory might appear similar at first to those for networks. Do not confuse these conventions. Capacity is normally measured in units of "kilobytes," "megabytes," and "gigabytes." In this non-network usage, 'K' represents a multiplier of 1,024 and 'k' represents a multiplier of 1,000 capacity. The following equations define the mathematics behind these terms:

27. 1 KB = 1,024 bytes • 1 kB = 1,000 bytes • 1 MB = 1,024 KB • 1 GB = 1,024 MB