Computer networking fundamentals

Introduction to local Area Networks

HUB • A hub is the most basic central connecting device. • Hubs enable computer on a network to communicate. • A host sends data to the hub. The hub sends the data to all devices connected to the hub.

Switch • Switches work the same way as a hub, but they can identify the intended recipient of the data. • Switches can send and receive data at the same time Router • Routers enable computers to communicate and allow Communication between two networks- such as your home network and the internet. • This communications link between the one network and the others is where the LAN ends. Serial Data Transfer and IP Addresses • Serial data transfer is the transfer of one bit at a time – in other words, transfer in a single-bit stream, like a one lane highway. • On the network cable, data travels in a single bit stream. Data Transfer Rate • Data transfer rate defines the maximum bits per second (bps) that can be transmitted over an network. • Rated in bits and signified with a lower case b (for example, 10 Mbps). • The lowercase b differentiates this unit form data that is stored on a hard drive which uses an upper case B that stands for bytes (for example 10MB). Types Of Transfers • Broadcast sends data to every other hosts on the network. • Unicast sends data to a Specific host.

  IP Address • Most every computer and many other devices have an Internet Protocol (IP) address. • An IP Address uniquely identifies your devices and the associated network and allows each devices to send and receive information. • A typical example of an IPv4 address would be 192.168.1.1 • Every IP address is broken down into parts by a subnet address • Network ID 192.168.1.1 • Host ID 1 Virtual LAN • A virtual LAN (VLAN) is a group of hosts with a common set of requirements that communicate as if they were connected together in a normal fashion on switch. Network Topology • A network topology defines the physical connections of hosts in a computer network. • There are several types of physical topologies including 1. Bus 2. Ring 3. Star 4. Mesh 5. Tree

Star Topology • Most common topology • Each computer is individually wired to a central connecting device (hub, switch or SOHO router) with twisted-pair cabling. Ring Topology • In a LAN environment, each computer is connected to the network using a closed loop. • Used by token Ring and Fiber Distributed Data Interface (FDDI). Mesh Topology • Most common topology. • Each computer is individually wired to a central connecting device is needed. Token Ring • A Token Ring network send data logically in a ring fashion meaning that a token goes to each computer, one at a time, and continues on in cycles. • Physically token Ring computers are connected in a star fashion, central connecting devices known as a multi station access unit (M AU or ASAU).

Ethernet • Institute of Electrical and Electronics Engineers (IEEE) Standard (802.3) that defines how information is sent and received between network adapters, hubs, switches, and other devices. • Ethernet is the defector standard is the most widely- installed local area network technology. • Common types of Ethernet include: • 802.3v or Fast Ethernet that runs at 100Mpbs. • 802.3ab or Gigabit Ethernet. Frames • Computers on Ethernet networks communication via frames. • A frame is a sequence of bits containing a detectable beginning and end of packet in the stream of bits. • A frame is a data packet residing on Layer 02 of the OSI model. Types of computing • Computing is done at a central 10 cation using terminal that are attached to this main system. • Main frames are powerful computer and known as terminals (or dubs terminals). • Each terminal consisted solely of a keyboard and display with no processing power.

Client /Server model • The client/server model is an architecture that distributes applications between severs and client computers. • Server- system that provides services such as windows7. Peer-to-peer networking • Peer-to-peer networking distributes applications or workloads between computers. • Peer are both service providers and service requestors. Distributed Computing • Distributive computing includes both clients-sever and peer-to-peer networks. • Every devices or workstation has its own processing power. Servers • More Powerful computers that provide centralized services. 1. File 2. Database 3. Messaging/Email 4. Print 5. Network controller 6. Web

P2P • Peer-to-Peer or P2P has recently talking on an additional meaning. • P2P can also refer to file sharing networks. • Examples pf file sharing networks 1. Napster 2. Gnutella 3. G2 • Other technologies also take advantage of P2P File sharing: 1. Skype 2. VOIP 3. Cloud computing Summary • Understand local area networks (LANs), Including but not limited to LAN elements, design, perimeter networks, IP addressing, and LAN types. • Understand network topologies and access methods, including topologies such as star, mesh, and ring architecture ,and the client-server and peer-to-peer networks methods.