Computer Networking: TCP/IP

Computer Networking

TCP/IP

TCP/IP (Transmission Control Protocol/Internet Protocol) is a suite of protocols used for communication on the internet
Divided into four layers:
1. Network Access Layer ( Physical and Data Link layers of OSI model)
2. Internet Layer (Network layer of OSI model)
3. Transport Layer (Transport layer of The Open Systems Interconnection (OSI) model is a conceptual framework used to describe the architecture of telecommunications networks. Developed in the 1980s by the International Organization for Standardization (ISO), it provides a hierarchical structure for understanding the different layers of communication and data transfer in a network.
  
  Each layer of the OSI model serves a specific purpose, with each layer interacting with the layer above and below it to ensure the efficient transfer of data. There are seven layers in total, each with its own set of protocols and functions:
  1. Physical Layer: Defines how devices communicate over a physical medium, such as a network cable or wireless connection.
  2. Data Link Layer: Responsible for framing, error-checking, and error-correction of data as it is transmitted over the physical medium.
  3. Network Layer: Routes data between different networks and ensures data delivery to the correct destination.
  4. Transport Layer: Manages data transfer between applications, ensuring reliable and efficient data transfer.
  5. Session Layer: Establishes, manages, and terminates connections between applications.
  6. Presentation Layer: Converts data into a format that can be understood by the receiving device.
  7. Application Layer: Provides services to applications, such as sending and receiving email, browsing the web, and instant messaging.
  The TCP/IP protocol suite is a specific implementation of the OSI model, with many of its layers mapping directly to corresponding OSI model layers. However, TCP/IP also introduced some significant changes, including the combination of the OSI model's Transport and Session layers into a single entity called the Transport Layer.
  
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4. Application Layer (Session, Presentation, and Application layers of OSI model)
Key protocols:
- TCP (Transmission Control Protocol): reliable, connection-oriented
- IP (Internet Protocol): connectionless, routing
- UDP (User Datagram Protocol): unreliable, connectionless
- ICMP (Internet Control Message Protocol): error-reporting and diagnostics
- DHCP (Dynamic Host Configuration Protocol): dynamic IP address assignment

Network Topology

Physical and logical arrangement of devices in a network
Types:
- Physical Topology:
  - Bus
  - Star
  - Ring
  - Mesh
- Logical Topology:
  - Broadcast
  - Point-to-Point
  - Point-to-MultiPoint

Routing Protocols

Used to determine the best path for forwarding packets between networks
Types:
- Distance-Vector Protocols:
  - RIP (Routing Information Protocol)
  - IGRP (Interior Gateway Routing Protocol)
- Link-State Protocols:
  - OSPF (Open Shortest Path First)
  - IS-IS (Intermediate System to Intermediate System)
- Hybrid Protocols:
  - EIGRP (Enhanced Interior Gateway Routing Protocol)

Network Security

Threats:
- Unauthorized access
- Malware (viruses, worms, Trojan horses)
- Denial of Service (DoS) attacks
Security measures:
- Firewalls
- Encryption (SSL/TLS, IPSec)
- Authentication and Authorization
- Access Control Lists (ACLs)

Wireless Networking

Uses radio waves to transmit data between devices
Types:
- WiFi (IEEE 802.11)
- Bluetooth
- WiMAX
Security concerns:
- Unauthorized access
- Interference
- Encryption

Cables

Used for wired connections
Types:
- Coaxial cables
- Twisted pair cables (UTP, STP)
- Fiber optic cables

Networking Devices

Routers: connect multiple networks, route packets
Switches: connect multiple devices, forward packets
Bridges: connect two networks, forward packets
Gateways: connect multiple networks, route packets
Modems: connect to the internet via broadband

OSI Model

7-layered model for network communication
Layers:
1. Physical (Layer 1)
2. Data Link (Layer 2)
3. Network (Layer 3)
4. Transport (Layer 4)
5. Session (Layer 5)
6. Presentation (Layer 6)
7. Application (Layer 7)

Computer Networking

TCP/IP

TCP/IP is a suite of protocols used for communication on the internet
Divided into four layers: Network Access, Internet, Transport, and Application
TCP is a reliable, connection-oriented protocol
IP is a connectionless, routing protocol
UDP is an unreliable, connectionless protocol
ICMP is used for error-reporting and diagnostics
DHCP is used for dynamic IP address assignment

Network Topology

Refers to the physical and logical arrangement of devices in a network
Physical Topology types: Bus, Star, Ring, Mesh
Logical Topology types: Broadcast, Point-to-Point, Point-to-MultiPoint

Routing Protocols

Used to determine the best path for forwarding packets between networks
Distance-Vector Protocols: RIP, IGRP
Link-State Protocols: OSPF, IS-IS
Hybrid Protocols: EIGRP

Network Security

Threats: Unauthorized access, Malware, Denial of Service (DoS) attacks
Security measures: Firewalls, Encryption, Authentication and Authorization, Access Control Lists (ACLs)