Networking and Telecommunications

Chapter 7

Opening Questions

• What are some advantages of networked computing relative to stand alone computing?

• What is the difference between client/server and peer-to-peer networks?

• What are a few common types of network topologies?

NETWORK BASICSNETWORK BASICS

• Telecommunication system - enable the transmission of data over public or private networks

• Network - a communications, data exchange, and resource-sharing system created by linking two or more computers and establishing standards, or protocols, so that they can work together

Why Use Networks in Organizations?

• All networks offer advantages relative to using a standalone computer…

• that is, a computer that is not connected to other computers and that uses software applications and data stored on its local disks

• Networks allow multiple users to share devices such as printers, and share data, for example spreadsheets which are collectively known as network resources.

• Networks allow multiple users to share devices such as printers, and share data, for example spreadsheets which are collectively known as network resources.

Advantages to using a Network• Sharing devices save

money!

• For example, rather than buying 20 printers for 20 office workers, a company can have one printer and have those 20 office workers share it over a network.

• Sharing devices save money!

• For example, rather than buying 20 printers for 20 office workers, a company can have one printer and have those 20 office workers share it over a network.

• Sharing devices also saves time!

• For example, its faster for coworkers to data over a network than to copy data to a removable storage device and physically transport the storage device fro one computer to another.

Sneakernet: an out-dated file-sharing method in which people had to physically transport data files from one desktop to another, presumably wearing sneakers!

Sneakernet: an out-dated file-sharing method in which people had to physically transport data files from one desktop to another, presumably wearing sneakers!

Why else use networks?

• One of the highest priority network services is email!

• Reasons for networks include;

1. File & Print services2. Remote user access3. Mail services4. Internet services5. Management Services

• Traffic monitoring• Load balancing• Security auditing• Backup and restoration

servicesMost of these listed features require a NOS, a component of a Client/Server Network

NETWORK BASICS• Networks are differentiated by the

following:– Architecture - peer-to-peer, client/server– Topology - bus, star, ring, hybrid,

wireless– Protocols - Ethernet, Transmission

Control Protocol/Internet Protocol (TCP/IP)

– Media - coaxial, twisted-pair, fiber-optic

• Networks are differentiated by the following:– Architecture - peer-to-peer, client/server– Topology - bus, star, ring, hybrid,

wireless– Protocols - Ethernet, Transmission

Control Protocol/Internet Protocol (TCP/IP)

– Media - coaxial, twisted-pair, fiber-optic

NETWORK TYPES

• The three types of networks include:1. Local area

network (LAN)

2. Metropolitan area network (MAN)

3. Wide area network (WAN)

Difference between MANS and WANS

• MANS: networks that extend beyond the boundaries of a building.

• It is a network that is larger than a LAN and connects clients and servers from multiple buildings

• WANS: a network that connects two or more geographically distinct LANS or MANS.

• Different than MANs because they typically transport data over much longer distances than MANs and as such often require different transmission methods, media, and use a greater variety of technologies

• WANS: a network that connects two or more geographically distinct LANS or MANS.

• Different than MANs because they typically transport data over much longer distances than MANs and as such often require different transmission methods, media, and use a greater variety of technologies

LANs, MANs, and WANs Illustrated

Within the confines of a room or single buildingWithin the confines of a room or single building

Connecting LANs from multiple buildingsConnecting LANs from multiple buildings

Commonly connects separate offices from the same organization, whether they are across town or across the world

Commonly connects separate offices from the same organization, whether they are across town or across the world

ARCHITECTURE• There are two primary

types of architectures– Peer-to-peer (P2P)

network – Client/server network

• Peer-to-peer: is the simplest type of network; every computer can communicate directly with every other computer

Note: P2P networks do not use a centralized server

Advantages & Disadvantages to P2P Networks

Advantages• Simple to configure (Most

home networks are P2P)

• Typically less expensive to setup and maintain than other types of networks.

• Simple to configure (Most home networks are P2P)

• Typically less expensive to setup and maintain than other types of networks.

Disadvantages• Not very flexible: as P2P networks

grow, adding or changing significant elements of the network can be difficult

• Not very secure: data and other resources shared by network users can be easily discovered and used by unauthorized users

• Resource Sharing is not practical: each user is responsible for configuring Shared Docs and preventing access to other files: Meaning resource sharing is not controlled by a central computer or authority

• Not very flexible: as P2P networks grow, adding or changing significant elements of the network can be difficult

• Not very secure: data and other resources shared by network users can be easily discovered and used by unauthorized users

• Resource Sharing is not practical: each user is responsible for configuring Shared Docs and preventing access to other files: Meaning resource sharing is not controlled by a central computer or authority

Client/Server Networks• Client/Server networks:

use a central computer, known as a Server to facilitate communication and resource sharing between other computers on a network, which are known as Clients.

• In terms of resource sharing you can compare the client/server network to a public library: Librarians manages the use of books and other media by patrons, a server manages the use of shared resources by clients…

• In terms of resource sharing you can compare the client/server network to a public library: Librarians manages the use of books and other media by patrons, a server manages the use of shared resources by clients…

Client/Server Networks

• Client/Server network

Advantages of a Client/Server NetworkAdvantages of a Client/Server Network

• Provide User logon accounts and passwords for user of the network

• Access to multiple shared resources can be centrally granted to a single user or groups of users

• Problems on the network can be tracked, diagnosed and often fixed from one location

• Optimized for faster processing time to handle many requests from clients

• Larger disk space means it is more scalable and more clients can be added as necessary

TOPOLOGY

• Network topology - refers to the geometric arrangement of the actual physical organization of the computers and other network devices) in a network– Bus– Star– Ring– Hybrid– Wireless

• Network topology - refers to the geometric arrangement of the actual physical organization of the computers and other network devices) in a network– Bus– Star– Ring– Hybrid– Wireless

Bus/Star/Ring Topologies

Bus Topology(linear bus)

All devices are connected to a central cable, called the bus or backbone. These networks are relatively inexpensive and easy to install for small networks

Star Topology All devices are connected to a central device, called a hub. Star networks are relatively easy to install & manage, but bottlenecks can occur because all data must pass through the hub

Ring Topology The ring topology connects computers on a single circle of cable. Signals travel around the loop in one direction and pass through each computer acting like a repeater to boost the signal and send it on to the next computer.

Hybrid / Wireless Topologies

Hybrid Topology Groups of star-configured workstations are connected to a linear bus backbone cable, combining the characteristics of bus and star topologies

Wireless Devices are connected by a receiver/transmitter to a special network interface card that transmits signals between a computer and a server---all with an acceptable transmission range

NETWORK TOPOLOGY

Protocols• A protocol is a standard

that specifies the format of data as well as the rules to be followed during transmission

• Simply put, for one computer to talk to another computer, they must be speaking the same language.

• Protocols provide the langauge

IEEE 802.3 or Ethernet Protocol

• The committee that addresses LAN standards is called the IEEE 802 Committee.

– Thus, IEEE LAN protocols always start with the number 802.

• Today, the world’s most popular protocol for LAN is the IEEE 802.3 protocol.

• The committee that addresses LAN standards is called the IEEE 802 Committee.

– Thus, IEEE LAN protocols always start with the number 802.

• Today, the world’s most popular protocol for LAN is the IEEE 802.3 protocol.

– This protocol standard, also called Ethernet, specifies hardware characteristics such as which wire carries which signals.

– It also describes how messages are to be packaged and processed for transmission over the LAN.

IEE 802.3 or Ethernet Protocol (Continued)

• Most personal computers today are equipped with an onboard NIC that supports what is called 10/100/1000 Ethernet.

– These products conform to the 802.3 specification and allow for transmission at a rate of 10, 100, or 1,000 Mbps.

– Communications speeds are expressed in bits, whereas memory sizes are expressed in bytes.

Ethernet Packets

• The actual data to be sent• Media Access Control (MAC): Address of the

packets source• The MAC address of the intended recipient• A Cyclic Redundancy Check or (CRC code)

Security PerspectiveSecurity Perspective

• This system of allowing each machine to decide which packets to process does not provide any security.

• Keep in mind that any device that can connect to the network cable can conceivably capture any data packet transmitted across the wire. Many network diagnostic programs, commonly referred to as packet sniffers, can tell a NIC to run in promiscuous mode.

• Running in promiscuous mode, the computer will process all packets that it sees on the cable, regardless of the specified MAC addresses.

• Packet sniffers can be valuable troubleshooting tools in the right hands, but Ethernet provides no protections against unscrupulous use.

• If security of the data is important, consider installing some type of additional encryption software to safeguard your data

• Running in promiscuous mode, the computer will process all packets that it sees on the cable, regardless of the specified MAC addresses.

• Packet sniffers can be valuable troubleshooting tools in the right hands, but Ethernet provides no protections against unscrupulous use.

• If security of the data is important, consider installing some type of additional encryption software to safeguard your data

MEDIA

• Network transmission media - refers to the various types of media used to carry the signal between computers– Wire media (guided)– Wireless media (unguided)

Wire Media

• Wire media - transmission material manufactured so that signals will be confined to a narrow path and will behave predictably

• Three most commonly used types include: 1. Twisted-pair wiring 2. Coaxial cable3. Fiber optic (or optical fiber)

Wire Media

Wireless Media

• Wireless media - natural parts of the Earth’s environment that can be used as physical paths to carry electrical signals

• Atmosphere and outerspace are examples of wireless media that commonly carry signals

Networking Hardware BasicsHubs Connectivity device that retransmits

incoming data signals to its multiple ports –Typically used for Star topologies and use twisted pair cabling

Repeaters A device used to regenerate a signal—addresses a transmission signal problem called attenuation

Bridges Allows large networks to be broken up into segments-segments are connected by a bridge----manages bandwidth

Switch Also manages bandwidth on a large network—further divides a network into smaller domains

Router Routing device that examines each packet of data it receives and then decides which way to sent it towards its destination

Home Network or Small Business

Small to Medium Sized Business Small to Medium Sized Business

E-Business Networks

• Today’s industry-leading companies have developed internet-based products and services to handle many aspects of customer and supplier interactions

• This means;• Integrating online

purchases with inventory and POS systems so that customers have a seamless experience between purchase and return or service

• This means;• Integrating online

purchases with inventory and POS systems so that customers have a seamless experience between purchase and return or service

E-BUSINESS NETWORKS

Virtual Private Networks:

• Uses public telecommunication infrastructure (usually the Internet) to provide secure access to an organizations network

• Provides users remote access capability to network resources

How Hospitals are Taken Advantage of Network tech

How Hospitals are Taken Advantage of Network tech

• Wireless Networking• RFID• Electronic Health

Records

Increased Use of Technology

• The medical industry is attempting to increase efficiency and functionality by adopting technology. This technology takes the form of electronic medical records, radio frequency identification for patient tracking, and wireless networking among other technologies.

• These technologies increase the productivity of institutions but, also introduce new risks to patient privacy.

• The medical industry is attempting to increase efficiency and functionality by adopting technology. This technology takes the form of electronic medical records, radio frequency identification for patient tracking, and wireless networking among other technologies.

• These technologies increase the productivity of institutions but, also introduce new risks to patient privacy.

Examples of new tech used in Healthcare

• RFID: radio frequency identification combined with wireless networking technology.

– RFID tags used could be used in conjunction with patient’s cell phones to provide a wide variety of dietary and health related information when buying groceries

• The literature states that wireless network technology and RFID’s could provide medical providers with “location tracking, body sensors, and short range wireless communications for monitoring the health of patients.

Concerns with RFID’s

• YouTube Video: Privacy Concerns

Emerging Technologies: teleprensence

Telepresence