Computer network

• A collection of interconnected devices that share resources and communicate using standard protocols.

OSI model

• A framework that divides networking into 7 layers: Physical, Data Link, Network, Transport, Session, Presentation, and Application.

TCP vs UDP

• TCP is reliable and connection-oriented. UDP is faster, connectionless, and less reliable.

IP Address

• A unique identifier for devices on a network, used for routing data between them.

IPv4 vs IPv6

• IPv4: 32-bit, supports 4.3 billion devices. IPv6: 128-bit, supports a vastly larger number of devices.

MAC Address

• A unique hardware identifier for network devices used at the Data Link Layer.

DNS (Domain Name System)

• Translates domain names (e.g., google.com) into IP addresses for communication.

DHCP (Dynamic Host Configuration Protocol)

• Automatically assigns IP addresses to devices in a network, simplifying management.

Subnet Mask

• Defines the network and host portions of an IP address, aiding in efficient IP address allocation.

Router vs Switch

• Router: Connects multiple networks and routes data between them.
• Switch: Connects devices within a network, forwarding data based on MAC addresses.

Hub vs Switch

• Hub: Broadcasts data to all devices.
• Switch: Directs data to the intended recipient.

Firewall

• Controls incoming and outgoing network traffic based on security rules, protecting against unauthorized access.

NAT (Network Address Translation)

• Translates private IP addresses to a public one, allowing multiple devices to share a single public IP.

Static vs Dynamic IP Addressing

• Static: Manually assigned and permanent.
• Dynamic: Automatically assigned via DHCP and can change over time.

VPN (Virtual Private Network)

• Creates an encrypted tunnel for secure communication over a public network like the internet.

Three-Way Handshake (TCP)

• Used to establish a TCP connection: SYN, SYN-ACK, and ACK packets are exchanged to confirm readiness.

Proxy Server

• Acts as an intermediary between client and server, often used for security, caching, and anonymity.

ARP (Address Resolution Protocol)

• Resolves IP addresses to MAC addresses, enabling devices to communicate on a local network.

Latency

• The delay between sending and receiving data, measured in milliseconds (ms).

Bandwidth

• The maximum rate of data transfer across a network, measured in bits per second (bps).

Throughput

• The actual rate of successful data transfer, often lower than bandwidth due to network conditions.

Packet Loss

• Occurs when one or more packets fail to reach their destination due to network issues.

VLAN (Virtual Local Area Network)

• A logical grouping of devices within a network, improving segmentation and security.

Socket

• An endpoint for communication, identified by an IP address and port number, facilitating data transfer between devices.

Port Forwarding

• Maps external traffic to a specific internal IP and port, allowing access to services on a private network.

Load Balancer

• Distributes traffic across multiple servers to enhance performance and reliability.

ICMP (Internet Control Message Protocol)

• Used for error reporting and diagnostic functions like ping to check connectivity.

Traceroute

• A tool that shows the path packets take from one device to another, used for troubleshooting network issues.

SSL/TLS

• Security protocols that encrypt data sent over the internet, ensuring secure communication.

CDN (Content Delivery Network)

• A network of distributed servers that deliver web content from locations closer to users for faster access.

QoS (Quality of Service)

• Techniques to prioritize certain types of traffic (e.g., VoIP) to ensure high performance for critical applications.

Collision Domain vs Broadcast Domain

• Collision Domain: A network segment where data collisions can occur.
• Broadcast Domain: A network segment where broadcast traffic is received by all devices.

BGP (Border Gateway Protocol)

• A protocol used to exchange routing information between different networks on the internet.

DNS Server

• Resolves domain names into IP addresses, enabling access to websites via human-readable names.

Half-Duplex vs Full-Duplex

• Half-Duplex: Data flows in one direction at a time.
• Full-Duplex: Data flows in both directions simultaneously.

Multicast

• Sends data to multiple devices in a group, more efficient than sending individual unicast messages.

Internet vs Intranet

• Internet: Global public network.
• Intranet: Private network within an organization.

Strongly Connected Components in Graph

• A component of a directed graph where every vertex is reachable from every other vertex in that component.

Bridges in Graph

• A bridge is an edge in a graph, whose removal increases the number of connected components in the graph.

Traceroute and Ping Difference

• Ping: Measures the round-trip time for packets.
• Traceroute: Shows the path packets take between devices, useful for troubleshooting.