Ethernet First network to provide CSMA/CD Is a fast and reliable network solution One of the most widely implemented LAN standards Can provide speeds in the range of 10Mbps- 10 Gbps Used with a bus or star topology

Types of Ethernet LANs 10Base-T Operates at 10 Mbps Fast Ethernet (100Base-T) Operates at 100 Mbps Gigabit Ethernet Operates at 1 Gbps Uses fiber optic cable 10 Gbps Ethernet Latest development of ethernet Wireless Ethernet Operates at around 2.4 Gbps

Fiber-Distributed Data Interface (FDDI) Fiber-Distributed Data Interface (FDDI) offers a standard for data transmission in a local area network that can cover in range up to 200 kilometers (124 miles). The FDDI protocol uses as its basis the token ring protocol. In addition to covering large geographical areas, FDDI local area networks can support thousands of users. it uses optical fiber

Fiber-Distributed Data Interface (FDDI) An FDDI network contains two token rings, one for possible backup in case the primary ring fails. FDDI has a larger maximum-frame size than standard 100 Mbit/s Ethernet, allowing better data. A small number of devices such as (routers….)

Wide Area Network (WAN) A network that uses long-range telecommunication links to connect 2 or more LANs/computers housed in different places far apart. Towns, states, countries Your home USA WAN Student Computer Centre

Example WAN technologies: Phone lines Satellite Internet ISDN – Integrated Service Digital Network T-Carriers ― basically digital phone lines ATM – Asynchronous Transfer Mode Broadband Cable Network Cable TV services have been widely developed in all modern cities. use coaxial cable installed (that are supposed to carry TV signals) to deliver broadband data services Many cable network wiring has been replaced with hybrid fiber-coax (HFC) use to connect to the subscribers’ buildings, and then the original coaxial cable to connect to each household

The connection is shared by a number of subscribers, hence may raise performance and security problems PC TV Fiber-optic cable Cable Drop Coaxial Cable Cable company

Metropolitan Area Network (MAN) Large network that connects different governments Shares local resources

Network Components Physical Media Interconnecting Devices Computers Introduction to Computer Networks Network Components Physical Media Interconnecting Devices Computers Networking Software Applications

Networking Media/ transmission Media Introduction to Computer Networks Networking Media/ transmission Media It which signals (data) are sent from one computer to another: Wire wireless

Wire twisted pair (TP) Coax-Cable: two insulated copper wires Category 5: 100 Mbps, 1 Gpbs Ethernet Category 6: 10Gbps Coax-Cable: Consists of single copper wire surrounded by three layers of protecting and metal materials Typically used for cable TV

low error rate Fiber-optics: Strands of glass or plastic used to transmit light Very high capacity, low noise, small size low error rate

twisted-pair cable twisted-pair wire protective coating glass cladding plastic outer coating woven or braided metal insulating material copper wire twisted-pair cable twisted-pair wire protective coating glass cladding optical fiber core

Coaxial cable BNC T-Connector Network Card

Wireless Broadcast Radio Distribute signals through the air over long distance Uses an antenna Typically for fixed locations Cellular Radio A form of broadcast radio used for mobile communication High frequency radio waves to transmit voice or data

Microwaves Infrared (IR) Radio waves for high speed transmission Used for satellite communication Infrared (IR) Wireless transmission media that sends signals using infrared light- waves

Networking Devices HUB Switches Routers Wireless Access Points Modems etc.

Coaxial link from cable TV socket Ethernet link to PC Modem Coaxial link from cable TV socket

Hub Nodes are connected to a hub via channels. When data is received from a node it is broadcast to all the other ports. This is ineffective as the data is intended for only one of the other nodes. Stackable hubs with 8, 16 or 24 ports can be linked to form large LANS. It may also amplify the signal for long distances.

Switch A switch is sometimes known as an intelligent hub. When data is received from a node it is examined and then sent directly to the destination known. This is more effective than a hub as the data goes directly to the destination node. Switches are more complex than hubs and are therefore more expensive.

Router Routers connect different networks together. They control and manage the flow of data over the different networks. They connect smaller networks into larger internetworks. They connect LANS to telecommunications lines and the Internet. They manage with the differences in topologies and transmission media. CS Topic 4 - Networks v2

A wireless access point (WAP) is a hardware device on a local area network (LAN) that allows wireless capable devices and wired networks to connect through a wireless standard, including Wi-Fi or Bluetooth. WAPs feature radio transmitters and antennae, which facilitate connectivity between devices and the Internet or a network. A WAP is also known as a hotspot.

Network Structure Client / Server Peer to Peer (P2PN)

Peer-to-Peer Networks Peer-to-peer network is also called workgroup No hierarchy among computers  all are equal No administrator responsible for the network

Advantages of peer-to-peer networks: Low cost Simple to configure User has full accessibility of the computer No specialized services required Disadvantages of peer-to-peer networks: No more security Difficult to loading 10 or less users Security is not an issue Only limited growth in the likely future

Clients and Servers Clients (Workstation) Servers Computers that request network resources or services Servers Computers that manage and offer network resources and services to clients Usually have more processing power, memory and hard disk space than clients It can manage data, users, groups, security, and applications on the network Servers often have a more stringent performance and trust

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Advantages of client/server networks Facilitate resource sharing – centrally administrate and control Facilitate system backup and improve error Improve security – only administrator can have access to Server Maintenance more users – difficult to achieve with peer-to-peer networks Disadvantages of client/server networks High cost for Servers Need skilled to configure the network