Networks

In Information Technology (IT), networks are defined as:

---

Definition

A network is a collection of interconnected devices (such as computers, servers, routers, and switches) that communicate and exchange data using a common set of protocols over wired or wireless connections.

Key Concepts in IT Networks:

1. Nodes Devices on the network (e.g., computers, printers, mobile devices, servers).

2. Links Communication pathways—either wired (Ethernet, fiber) or wireless (Wi-Fi, Bluetooth).

3. Protocols Rules governing data communication (e.g., TCP/IP, HTTP, FTP, DNS).

4. Topology The layout of how devices are connected:

   • Star, Bus, Ring, Mesh, etc.

5. Types of Networks:

   • LAN (Local Area Network): A network in a limited area (e.g., home, office).
   • WAN (Wide Area Network): Covers large geographical areas (e.g., the Internet).
   • MAN (Metropolitan Area Network): Spans a city or large campus.
   • PAN (Personal Area Network): Small range (e.g., Bluetooth devices).
   • WLAN (Wireless LAN): A LAN using wireless connections.

6. Network Devices:

   • Router: Directs data between networks (e.g., home to Internet).
   • Switch: Connects devices within a LAN.
   • Firewall: Controls traffic based on security rules.
   • Access Point: Allows wireless devices to join a wired network.

7. Network Services:

   • IP addressing
   • DNS (Domain Name System)
   • DHCP (Dynamic Host Configuration Protocol)
   • VPN (Virtual Private Network)

---

Planes(Systems/Networks)

1. Data Plane: Carries the actual user/application traffic
2. Control Plane: Decides how data flows
3. Signalling Plane: Establishes, modifies, and tears down communication sessions
4. Management Plane: Provides configuration, monitoring, and administration of the system
5. Application Plane: Defines the actual end-user logic and business semantics.
6. Security Plane: Enforces security policies across data/control/management planes

---

Organizing topics

The topics will be arranged in terms of the OSI Model.

The following is a list of topics under Networks.

1. Data Communication: Components of a Data Communication System, Simplex, Half- Duplex and Duplex Modes of Communication; Analog and Digital Signals; Noiseless and Noisy Channels; Bandwidth, Throughput and Latency; Digital and Analog Transmission; Data Encoding and Modulation Techniques; Broadband and Baseband Transmission; Multiplexing, Transmission Media, Transmission Errors, Error Handling Mechanisms.

2. Computer Networks: Network Topologies, Local Area Networks, Metropolitan Area Networks, Wide Area Network, Wireless Networks, Internet.

Network Models: Layered Architecture, OSI Reference Model and its Protocols; TCP/IP Protocol Suite, Physical, Logical, Port and Specific Addresses; Switching Techniques.

3. Functions of OSI and TCP/IP Layers: Framing, Error Detection and Correction; Flow and Error Control; Sliding Window Protocol, HDLC, Multiple Access – CSMA/CD, CSMA/CA, Reservation, Polling, Token Passing, FDMA, CDMA, TDMA, Network Devices, Backbone Networks, Virtual LANs.

IPv4 Structure and Address Space; Classful and Classless Addressing; Datagram, Fragmentation and Checksum; IPv6 Packet Format, Mapping Logical to Physical Address (ARP), Direct and Indirect Network Layer Delivery; Routing Algorithms, TCP, UDP and SCTP Protocols; Flow Control, Error Control and Congestion Control in TCP and SCTP. World Wide Web (WWW): Uniform Resource Locator (URL), Domain Name Service (DNS), Resolution - Mapping Names to Addresses and Addresses to Names; Electronic Mail Architecture, SMTP, POP and IMAP; TELNET and FTP.

4. Network Security: Malwares, Cryptography and Steganography; Secret-Key Algorithms, Public-Key Algorithms, Digital Signature, Virtual Private Networks, Firewalls.

5. Mobile Technology: GSM and CDMA; Services and Architecture of GSM and Mobile Computing; Middleware and Gateway for Mobile Computing; Mobile IP and Mobile Communication Protocol; Communication Satellites, Wireless Networks and Topologies; Cellular Topology, Mobile Adhoc Networks, Wireless Transmission and Wireless LANs; Wireless Geolocation Systems, GPRS and SMS.

6. Cloud Computing and IoT: SaaS, PaaS, IaaS, Public and Private Cloud; Virtualization, Virtual Server, Cloud Storage, Database Storage, Resource Management, Service Level Agreement, Basics of IoT.