Networks: The Big Picture
-
Upload
international-school-of-curitiba -
Category
Education
-
view
164 -
download
2
description
Transcript of Networks: The Big Picture
![Page 1: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/1.jpg)
NetworksThe Big Picture
![Page 2: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/2.jpg)
Three Great Leaps of Civilization
![Page 3: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/3.jpg)
Computer Network
Single Computer Network of Computers
![Page 4: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/4.jpg)
Why Network?
• Access information• Exchange information• Networks help people work faster and
smarter by making information available when they need it, where they need it.
Makes distances between computers invisible.
![Page 5: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/5.jpg)
Network Services and BenefitsSharing Information
You and other network users can have access to the same information.
Accessing remote information
You can use your personal devices to access information through a public information service.
CommunicatingYou can exchange messages with a local group or around the world in a quick and paperless form of communication.
Sharing ApplicationsYou and several other users can have access to the same application software; for example everyone in a work group can upgrade simultaneously.
Sharing Network ResourcesNetworks allow users to share connected devices (i.e. printers)
![Page 6: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/6.jpg)
Overview of Computer Networks
• A network suggests a collection of related things or people that are somehow interconnected.
• In a computer network the interconnected parts are computers, peripherals and other devices that communicate with one another.
• A computer network may connect as few as two computers or as many as thousands even millions.
![Page 7: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/7.jpg)
Computer Networks
This is a Network. This is not a Network.
![Page 8: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/8.jpg)
Network Evolution
![Page 9: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/9.jpg)
Host-Based computing
![Page 10: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/10.jpg)
Decentralized computing
![Page 11: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/11.jpg)
Peer-to-peer computing
![Page 12: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/12.jpg)
Cloud computing
![Page 13: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/13.jpg)
What is a computer network made of?
• Network Components– Hardware: clients and servers; shared devices
(peripherals); hubs, routers and switches– Software: applications and underlying control
software that allows the components to work together
– Network Media: fiber optics, wireless (infrared and radio)
![Page 14: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/14.jpg)
Clients and Servers
Client computers•Regular desktop, laptop, or mobile devices that connect to a network to use its services.•When connecting to a network, clients normally have to authenticate themselves using a username and password.
![Page 15: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/15.jpg)
Clients and Servers
Servers •Assigned responsibility for certain tasks for the whole network, provide services for other computers (clients)
– File servers– Application servers– Print servers– Database server– Authentication server (domain controller)– Firewall– Web server– Email server
![Page 16: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/16.jpg)
Shared Devices
![Page 17: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/17.jpg)
Hubs, Routers and Switches
All three allow multiple computers to be connected to them.
Difference: how each broadcasts data
![Page 18: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/18.jpg)
Hubs
• Most basic and cheapest of these devices• Broadcasts to every connected device,
including the one that sent it• Lot of wasted bandwidth
![Page 19: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/19.jpg)
Switches
• Smarter version of hubs• Inspect received data and forward to intended
recipient• Saves bandwidth compared to hubs
![Page 20: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/20.jpg)
Routers
• Connect two or more separate networks• Gateway through which all data entering and
leaving the network passes
![Page 21: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/21.jpg)
Network Architecture
Network architecture refers to the way computers are locally organized on a network, and the role each takes.
![Page 22: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/22.jpg)
Network Architecture
Client/ Server Network Peer-to-Peer Networks (P2P)
![Page 23: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/23.jpg)
Client/Server
Centralized on one or more computers that act as servers to the rest of the network
Centrally manage access control and provide a single location for file storage
Benefits Access from any client (not limited to one computer) Easier to backup files Better security (authenticate users and control access)
![Page 24: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/24.jpg)
Client/ Server
![Page 25: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/25.jpg)
P2P (Peer-to-Peer)
No central authority or control(all clients equal status)
User accounts have to be made on each machine for each use who wants access
Less security
Benefits Cost efficient
![Page 26: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/26.jpg)
Peer-to-Peer File Sharing
Sharing files over the internet without a central server
Every user both downloads they need and uploads the data they have.
Quicker downloading from single server
Concern: A means to illegally spread copyrighted material(e.g. Napster)
![Page 27: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/27.jpg)
Peer to Peer (P2P)
![Page 28: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/28.jpg)
Firewalls
Determine which data is allowed to enter and leave a network
Secure a computer by preventing network access from external unauthorized access
Control user connection to external networks
![Page 29: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/29.jpg)
Proxy Servers
Middle step between two computers(computer on LAN and web server on Internet)
All communication between the two passes through proxy
Caching, filtering, logging data
![Page 30: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/30.jpg)
Types of Networks
Local Area Networks (LAN) Wireless LANs (WLAN) Personal Area Networks (PAN) Metropolitan Area Networks (MANs) Wide Area Networks (WAN) Storage Area Networks (SAN) Virtual Private Networks (VPN) Virtual LAN (VLAN)
![Page 31: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/31.jpg)
Protocols
• Network protocols are the rules that network devices must follow to successfully interact with one another.
• Protocols define the actual steps that any device or program must take to communicate with another device or program on the network.
![Page 32: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/32.jpg)
Protocols
TCP/ IP: Transmission Control Protocol
Internet Protocol
![Page 33: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/33.jpg)
Network Connections
Cables and other carriers of a network’s transmission signals are called media. Wired Connections Wireless Connections
![Page 34: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/34.jpg)
Wired Connections
Dialup Ethernet Cable Internet Access Fibre optic cables
![Page 35: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/35.jpg)
Wireless Connections
Wi-Fi WiMax BlueTooth 3G and 4G
![Page 36: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/36.jpg)
Network Media Characteristics
Transmission Speed
Maximum Length
Shielding Against Interference
Physical properties of different media types make them suitable for higher or lower rates of data transmission.
Signals transmitted cannot travel indefinitely. After a given distance, the signal begins to weaken, lose integrity, and experience severe distortion.
You can partially protect transmission by locating network cables away from potential sources of interference.
Signal interference and other factors can reduce media reliability, requiring transmission to be limited to lower speeds.
Distances can be amplified using devices such as repeaters, bridges, or by joining multiple networks.
Network cables are available with varying forms of shielding that can lessen the signal’s sensitivity to outside interference.
![Page 37: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/37.jpg)
Network Media Comparisons
![Page 38: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/38.jpg)
Network Media Comparisons
![Page 39: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/39.jpg)
Measuring Network Speed
• Bandwidth: Network’s speed; the quantity of information that can be transmitted through a communication medium in a given amount of time.
• Broadband: an Internet connection (DSL or cable modem) that offers higher bandwidth , and therefore faster transmission speed.
• Units of measurement: bps, Kbps, Mbps, Gbps
![Page 40: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/40.jpg)
Connecting Networks Together
• Routers: Hardware device used to connect two separate networks that decide the best “route” for Internet transmissions.
• Gateways: Computer which acts as a bridge between a local area network and the Internet.
![Page 41: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/41.jpg)
Preventing Unauthorized Access
![Page 42: Networks: The Big Picture](https://reader033.fdocuments.us/reader033/viewer/2022061618/5551eac1b4c905f56f8b4d20/html5/thumbnails/42.jpg)