Networks Fundamentals (Handwritten Notes ) ˚₊‧꒰ა 𐙚 ໒꒱ ‧₊˚

Section 1: Networks Fundamentals

• Focus: Understanding foundational concepts before diving into types.

Standards and Protocols

• Standards:

  • Defined as a set of guidelines or specifications that provide a foundation for compatibility and safety across all devices on a network.

  • All devices must adhere to the same standards to ensure successful communication.

• Protocols:

  • Standardized rules for data formatting and transmission between devices.

  • Integral in the OSI model layers, facilitate structured communication and assure authentication of users.

Types of Networks

• LAN (Local Area Network):

  • Connects devices within a limited geographical area.

  • Characterized by high data transfer rates and low latency, often relying on wired connections to routers/switches.

• VLAN (Virtual Local Area Network):

  • Segments a single LAN into multiple broadcast domains to group devices by factors such as department, enhancing security and minimizing unnecessary traffic.

• WAN (Wide Area Network):

  • Connects multiple LANs and networks over extensive geographical areas, typically utilizing both public and private infrastructures for long-distance communication.

• PAN (Personal Area Network):

  • Connects devices over short distance, often personal devices like smartphones and tablets.

Specialized Network Types

• SAN (Storage Area Network):

  • Provides high-speed access to storage devices and centralizes storage management.

• P2P (Peer to Peer):

  • Enables direct data transfer between devices without a central server. Both devices function both as clients and servers, commonly used for file sharing and collaborative applications.

OSI Model Breakdown

When being the sender of data it goes from 7 to 1 (Application to Physical layer)

• Layers Overview:

  • Application Layer:

    • Interfaces with end-user services (e.g., HTTP, POP3, SMTP).

    • Direct user interaction with underlying network layers.

  • Presentation Layer:

    • Formats data, controls encryption, and compresses data.

  • Session Layer:

    • Manages dialogues between computers, establishing and terminating connections.

  • Transport Layer:

    • Handles error control and flow, ensuring data packets reach their destinations accurately (TCP/UDP).

  • Network Layer:

    • Responsible for packet routing using IP addresses (IPv4/IPv6).

  • Data Link Layer:

    • Engages in the transmission of data in and out of the physical network (Ethernet, PPP).

  • Physical Layer:

    • Concerned with the physical means of data transfer, including the communication medium.

VPNs (Virtual Private Networks)

• Function:

  • Utilize encryption and authentication to secure connections over public networks, simulating a private network.

• VPN Server:

  • Remote server that receives encrypted traffic from relevant vpn clients, decrypts it, and allows for access to the internet by encrypting and redirecting traffic back to client.

• VPN Client:

  • Verifies user identity when attempting to connect to the VPN.

  • Connects users to the remote VPN server, creating the encrypted tunnel connection.

VPN Mechanisms

• Tunneling:

  • Establishes an encrypted connection between a device and the VPN server, ensuring secure data routing.

• Encryption:

  • Converts data into ciphertext, protecting it from interception during transmission.

  • Essential for safeguarding sensitive information.

VPN Protocols

• IPSec:

  • Encrypts and authenticates IP packets, ensuring data security.

  • Paired with LT2P

• L2TP:

  • Encapsulates data packets within L2TP frames for transmission over the Internet.

  • Paired with IPSEC.

• PPTP:

  • Designed for point-to-point communication, with weaker security features. Creates tunnel to do such, facilitating encrypted point to point communication.

Benefits of VPNs

• Secured private internet connections, especially useful over public Wi-Fi.

• Prevents bandwidth throttling by obscuring traffic.

• Facilitates geo-changing.

Downsides of VPNs

• Potential reduction in internet speeds due to routing and encryption processes.

• No absolute anonymity; law enforcement may access logs.

• S/E implications (especially societal) of internet anonymity.

Impact on Working Patterns

• VPNs create a more secure environment for data transfer.

• Allow for employees in different branches to connect to VPN IP addresses that’d be apart of the head branch local network to seamlessly work within the local network that permits IP addresses local to the coprorate office.

• Facilitate remote and global working conditions, such as accessing work documents securely through a corporate VPN.

  • Example: CEO in a remote location must connect to the company VPN to access important documents, with information shared securely over the local network.