Networking and the Internet

TERM DEFINITION
Network Classifications
  1. LAN:Local area network
  2. MAN:Metropolitan narea network
  3. WAN:Wide area network
Network models
  1. bus network:The machines are all connected to a common communication line called a bus.
  2. star network:One machine serves as a central focal point to which all the others are connected.
Protocols
  1. CSMA/CD Ethernet:Carrier Sense Multiple Access with Collision Detection
  2. CSMA/CA Wifi:Carrier Sense Multiple Access with Collision Avoidance.
Combining networks:
  1. repeater:repeater is little more than a device that passes signals back and dorth between the two original buses without considering the meaning of the signals.
  2. bridge:Like a repeater, it connects two buses.
  3. switch:is essentially a bridge with multiple connections, allowing it to connect several buses rather than just two.
  4. router:The connection between network to form an internet is handled by devices known as routers.
  5. gateway:The point at which one network is linked to an internet is often called a gateway.
Client/server model
  1. P2P: peer to peer
  2. distributed system:A software that use controls a network's infrastructure itself are designed as destributed system.
  3. cloud computing:whereby uge pools od shared computers on the nerwork can be allocated for use by clients as needed.
Internet Addressing
  1. Tier 1: At the top of this hierarchy are relatively few tier-1 ISP
  2. Tier 2: Tend to be more regional in scope and less potent in their capabilities
  3. Tier 3: Access to this core is usually provided by an intermediary called an access or tier-3 ISP.
IP address
  1. ICANN: Internet Corporation for Assigned Names and Numbers
  2. DNS: Domain name system, The name servers are used as an internet wide directory system.
  3. TLD: Top-level domain
  4. Country-code TLDs: resulting in the creation of new two-letter TLDs for each specific country.
Internet protocols
  1. FTP: File Transfer Protocol
  2. HTTP: Hyper Text Transfer Protocol
  3. SMTP: Simple Mail Transfer Protocol
World Wide Web
  • URL: Uniform Resource Locator
  • Client-side activities: They performed by a client.
  • Server-side activities: They are performed by a server.
Internet four-layer software
  • application layer:an abstraction layer that specifies the shared communication protocols and interface methods used by hosts in a communications network
  • trasport layer:The transport layer controls the reliability of a given link through flow control, segmentation and desegmentation, and error control.
  • network layer : Handles the routing and sending of data between different networks
  • link layer:The data link layer is concerned with local delivery of frames between nodes on the same level of the network.
Internet is
  • packet-switching network: is the transfer of small pieces of data across various networks.
  • fault tolerant: is a process that enables an operating system to respond to a failure in hardware or software.
  • redundant: exceeding what is needed or useful.
Cybersecurity
  • malware: Many attacks incorporate the use of malicious software.
  • virus: is software tha infectsa computer by inserting itself into programs that already reside in the machine.
  • worm: is an autonomous program that transfers itself through a network, taking up residence in computers and forwarding copies of itself to other computers.
  • Trojan horse:: is a program that enters a computer system disguised as a desirable program.
  • spyware: Another form of malicious software.
  • phishing:As opposed to obtaining infoemation secretly by sniffing via spyware.
  • DDoS attack:A distributed denial-of-service (DDoS) attack is a malicious attempt to disrupt normal traffic to a web property.
Protection
  • firewall: A primary prevention technique is to filter traffic passing through a point in the network.
  • spam filter: are firewalls designed to block unwanted email.
  • proxy server:is a software unit that acts as an intermediary between a client and servewr with the goal of shielding the client feom adverse actions od the server.
  • antivirus software: used to detect and remover the presence od known viruser and other infections
  • cryptography: the study of sending and receiving messages securely in the presence od adversaries.
  • pubilc key encryption: involves techinques by whic the encryption ad decryption algorithms are known, and one od the keys is known,but the encode message remain secure.