CS UNIT 2

• Unit 2 covers communication in networking

Networking Definitions

• ARPAnet: Advanced Research Projects Agency Network
• WAN: Wide area network, covers a very large geographical area
• LAN: Local area network, covers a small area like a single building
• MAN: Metropolitan area network, larger than a LAN but smaller than a WAN (can cover several buildings like a campus)
• File server: A network server where central files are stored, accessible to logged-in users
• Hub: Hardware that connects devices to form a LAN, directing incoming data packets to all devices
• Switch: Hardware that connects devices to form a LAN, directing data packets to a specific destination address
• Router: A device that enables data packets to be routed between different networks, like joining LANs to form a WAN
• Modem: Modulator demodulator, converts digital to analogue data (for phone lines) and vice versa
• WLAN: Wireless LAN
• (W)AP: Wireless access point, allows a device to access a LAN without a wired connection
• PAN: Network centered around a person or workspace
• Client-server: Network that uses separate dedicated servers and specific client workstations
• All client computers connect to the dedicated servers
• Spread spectrum technology: Wideband radio frequency with a range of 30-50 meters
• Node: A device connected to a network (computer, storage, etc.)
• Peer-to-peer: Network where each node shares files with all others, each node has its own data and there is no central server
• Thin client: Device needing internet access to work, relies on a powerful computer for processing
• Thick client: Works both offline and online, can do processing without a network connection
• Bus network topology: Uses a single central cable, data travels in one direction and only one device can transmit at a time
• Packet: Message/data sent over a network, includes sender/recipient addresses and the actual data
• Star network topology: Uses a central hub/switch, all devices connect to it and data packets are directed through it
• Mesh network topology: Interlinked computers/devices, uses routing logic to send data packets via the shortest route
• Hybrid network: Combination of different network topologies
• Cloud storage: Data storage on off-site servers
• Data redundancy: Same data stored on multiple servers for maintenance or repair purposes

Additional terms

• Wi-Fi: Wireless connectivity using radio waves/microwaves, implementing IEEE 802.11 protocols
• Bluetooth: Wireless connectivity using radio waves in the 2.45GHz band
• Spread spectrum frequency hopping: Transmitting radio signals by randomly picking one of 79 channels, range up to 100 meters
• WPAN: Wireless personal area network, connects devices in close proximity (laptop, smartphone, etc.)
• Twisted pair cable: Cable with two wires of a single circuit twisted together
• Coaxial cable: Cable made of a central copper core, insulation, copper mesh, and outer insulation
• Fibre optic cable: Cable with glass fibre wires, uses light pulses to transmit data
• Gateway: Device that connects LANs using different protocols
• Repeater: Device used to boost a signal on wired and wireless networks
• Repeating hubs: Network devices as a hybrid of hub and repeater unit
• Bridge: Device that connects LANs using the same protocols
• Softmodem: Software modem; software-based, uses minimal hardware
• NIC: Network interface card, allows devices to connect to a network/internet, usually with a MAC address
• WNIC: Wireless network interface cards/controllers
• Ethernet: Protocol IEEE 802.3 used by many wired LANs
• Conflict: Two devices have the same IP address
• Broadcast: Communication where data is sent from sender to receiver
• Collision: Two messages from different sources try to transmit along the same data channel
• CSMA/CD: Carrier sense multiple access with collision detection, method to detect and resolve collisions
• Bit streaming: Contiguous sequence of digital bits sent over a network/internet
• Buffering: Store which holds data temporarily
• Bit rate: Number of bits per second transmitted over a network, measures data transfer rate
• On-demand (bit streaming): System to stream video/music files from a central server without saving them to a device
• Real-time (bit streaming): System captures an event via camera/mic connected to a computer, sends to a server, accessed "as it happens"

Benefits of networking computers and devices

• Share devices and reduce costs
• Cheaper software licenses
• File and data sharing
• Central data access
• Central data backup
• Communication via email and messaging
• Network management with access rights and restrictions

Drawbacks of networking computers and devices

• Expensive cabling and servers
• Complex network management
• Breakdown of key devices affects the entire network
• Malware and hacking risks

Networked computers form an infrastructure including:

• Hardware: LAN cards, routers, switches, wireless routers, cabling
• Software: Network operation/management, firewalls, security applications/utilities
• Services: DSL, satellite communication, wireless protocols, IP addressing

Network categorization

• Private networks: Owned by a single entity, such as a company, for internal use with restricted access
• Public networks: Owned by communications carriers, used by many organizations without specific password requirements, although sub-networks may have security management

Client-Server model

• Users can access most files stored on dedicated servers
• Client sends request to server, server finds and sends data back
• A system administrator manages the network
• Server dictates data access
• Central security databases controlling access to shared resources via user login to access assigned resources only
• Easily scalable
• Central server handles email
• Stable system with nightly backups to restore deleted resources
• Clients have more control to store their own programs and data/files
• Cheaper to expand with low energy devices

Peer-to-Peer Model

• Each node joins the network to allow provision of services to all other networks

• Nodes on the network to simply access data from another node

• For communication with other peers connected to a network Suppliers and consumers are peers to be both suppliers and consumers.

• Nodes participate as equals on the network

• Does not have a central system

• Each node/workstation shares it files with all the others

• There is no requirement to authenticate users

Thick and thin clients have pros and cons:

• Thin client runs some software even if not connected to a server

• They rely heavily on local resources

• More tolerant of slow network connection

• Can store data in local resources (HDD or SSD)

• Less secure (relies on clients to keep their own data secure

• Each client needs to update data individually

• Data integrity issues, since many clients access the same data which can lead to inconsistencies

• High reliance on the server, if the server goes down, so does communication link for thick client

• Thin clients need a connection to a remote computer to work

• Requires very few local resources and fast connection for its to wirk

• Data us stored on a remote PC

• They are more robust device can carry out processing even when not on a server

• The serve can prevent hacker from accessing the device

Network topologies

• Devices linked to server of data updates and new software installation

Bus Topology

• Uses a single central cable to which all computers connect

Star Topology

• Uses a central hub/switch; each device connects to it

Mesh Topology

• Nodes are interlinked
• Uses routing logic to direct data
• Data is directed to destination by shortest route

Hybrid Topology

• Mixture of two or more different topologies

Ring Topology

• All computers have two network connectors
• Each connector is used to run clockwise and onticlockwise on the next node

Pros

• Relatively easy to expand
• It is easy to identify where faults on the network have occurred.
• Good privacy and security, since packets travel along dedicated routes.
• Is is simple to set up

Disadvantages

• A large amount of cabling is needed
• It is difficult and complex
• If one part of the cable breaks the entire network goes down

Public and private cloud computing storage systems

• Cloud storage stores data on offsite servers
• The same data is store on multiple servers for repairs to allow data access when needed

System examples:

• Private: Is storage provider by a dedicated environment behind a computer firewall
• Public: Is a storage environment where the customer and cloud storage provider are different companies
• Hybrids: Combination of public and private clouds
• There may be issues if a customer as slow and unstable network connection, high cost of storage capacity is required

Data security in the could

• Considers if personal are able to access data for monetary expenses
• Considers who can access data if building is hacked and safety provided with building housing the data
• Cloud software application are delivered to uses device using computing services
• A use will connecter t the internet and their cloud services supplier allows them to connect the software application

Wireless connectivity

• Both WIFI and Blues tooth use electromagnetic radiation
• Bluetooth sends and receives radio waves in different channels
• Bluetooth use key encryption to the WPAN
• WIFI uses spread spectrum technology more faster data/range than BLUETOOTH
• WIFI enabled device can access from the internet 100 meters away

Wired Cable facts

• Twisted pair cables are most common cable types

• They have the lowest rated

• Coaxial cable is most commonly used in televisions

• Fibre cable are used to send data over long distances

There a few more Pros and Cons

• Hardwares are network hardware can be written

• It is easier to expanded networks

• Some devices haves increased mobility to be in range

• Not needed to connected devices using cables

• Network Interface Card

• Wireless Network Interface cards are more ordinary

• Ethernet cable uses nodes and median to device use such as Ethernet cords

• Collisions can also occur and cause a collision

• NIC is needed to connection internet with a devices and it is a part of the hardware

• WiNics the card are use to connect using the internet

Bit Streaming (how file is delivered)

• It requires a high speed communications link
• Large file must undergo some data compression before transmission
• It also needs to undergo some buffering to ensure smoother media files

Media files delivered by:

• 1 No need to wait for a whole data download
• 2 Allow video, music files played on demand
• 3 No need for specialized hardware
• 4 Provides piracy protection making is more difficult to copy files
• However users can't streaming files if there is connection is lost and the security risks with downloading
• Band with is lost with no internet

On demand bit-streaming (when file is encoded and placed on web server)

• File is converted to steam format, then to user and video broadcast as required
• Can pause data as required

Real time (bit streaming) file upload

• An even it sent and uploaded file, a video sent to user device, footage cant be shared

Internet/WWW

Internet

• Massive network of networks, uses TCP/IP communication protocols

Word Wide Web(WWW)

• A collection Of web pages on a website

• Use of hypertext Mark language with uniform research location to web page address using Browsers that connects to DSN to address Internet services providing with a service Public and private switch telephone network used in traditional phones Over internet protocol converted images through the internet

• TCP/IP,IPv4,IPV6 are all addresses to connet too devices using number to identified devices using the internet

• Classless domain router Increased IP flexity by allowing to add a suffix to IIP address also has a code to compress address and subdivide network using address as well, a DNS as to finds domain names

IP address information

• Private IP address( like a home or office) help devices without needing a network
• Public IP address used to identify the ISP on internet

Website addressed useds HTML codes to search files using HTTP Internet uss transfer protocol to network while World Wide Web users and accesses internet files by using the web browsing with a file to device connecting via phone wire and router

Test your knowledge of network topologies, devices, and protocols. This quiz covers various aspects of computer networking, from data transmission methods to network devices and their functions. Review concepts like CSMA/CD, IP addressing, and network topologies.