NETWORKING DOCUMENTATION

Personal Area Network [PAN]

The network of devices we use in our homes. All are connected to a router which provides similar private IPv4 addresses like 192.168.31.29, 192.168.250 and so on till 255.

Local Area Network [LAN]

Collection of PANs makes up a LAN network. Usually in a building of office. A wireless connection will make it a W-LAN. W for Wireless.

Campus Area Network [CAN]

Collection of LANs makes up a CAN network. Usually in schools and organizations where 2-3 buildings of the campus are connected.

Metropolitan Area Network [MAN]

Collections of CANs is a MAN network. It is set up by ISPs of a city to connect them and configure together. It has range of a metro-city.

Wide Area Network [WAN]

Literally the World. What we say the Internet is the WAN network.

Storage Area Network [SAN]

When a storage pool is connected to a network it's a SAN network. It stores the data of the nodes or nodes can receive. It's like the cloud storage.

Enterprise Private Network [EPN]

A configured network by an Admin over the Enterprise. Only employee devices can be connected and access this network.

Virtual Private Network [VPN]

When two networks are connected, hackers can spoof them or admin can view their data. For privacy a tunneled network can be created by VPN services.

Subnet / Virtual LAN [VLAN]

P2P [Peer-to-Peer]

It is a model where two devices are connected to each other without any SERVER which controls the transmission of data and sets protocols. Thus, two nodes are directly connected.

Client-Server Architecture

In this model, devices are connected to a central controlling device, SERVER, which controls the data transmission protocols.

Bus / Line Topology

A cable is passed on which the sides of cables are connected to nodes. Uses Broadcast Method.

Star Topology

A central device is placed where the nodes are connected. Uses Broadcast Method.

Ring Topology

All nodes are in circle, for transmission, data passes through each in rotation. Uses Broadcast Method.

Tree Topology

Hierarchically the nodes are set up.

Mesh Topology

Each node connects to each one. Its fastest but most expensive. Uses Unicast method.

Hybrid Topology

A mix of topologies is a Hybrid one.

Network Interface Card [NIC]

It is the card which provides interface for network connection to devices. Installed in Motherboard. Contains the MAC and ARP resolver cache. Can be wired or wireless. RJ-45 is most common Ethernet Cable and port in NIC.

MAC is a alphanumeric unique address assigned to each NIC by the manufacturer. ARP cache resolves IP to MAC address mapping.

Hub

Broadcast connection device. One input port and 8 or more output ports. Does not filter data and cannot be configured. Sends packets to all devices, so not secure but cheaper.

Switches

Intelligent, configurable, expensive version of a hub. Multiple ports from 8 to 64.

Repeater

Strengthens signals over long distances.

Access Points

Has input/output ports and provides wireless connectivity. Built into routers for sharing internet by ISP.

Router

Wired device for routing data packets over large networks. Assigns private IPv4 addresses and converts to public IPs. Modern routers have Access Points and Switches integrated.

DHCP Server

Dynamic Host Configuration Protocal [DHCP] servers are a replacement to the old time BOOTP. It uses Port UDP 67 same as BOOTP. It automatically assigns private IP addresses to devices in a LAN.
It provides the IP addresses dynamically on lease. But a Reservation of IP can be made by configuring the DHCP server.

DORA Functionality

It is a set of functions when a device wants to connect to a DHCP server for a IP lease.

APIPA

Automatic Private IP Addressing [APIPA] is a feature in Windows OS where if DHCP server is not found, it assigns a private IP and Subnet Mask.
It is a static and manual form where the Windows provides the IP lease.

The IP range assigned is from 169.254.0.1 to 169.254.255.255 and A Subnet Mask of 255.255.0.0 / 16.

DNS Server (Domain Name System)

It translates web addresses to IP cause thats what computer want to connect to Servers.
A DNS server has a database of web addresses and their corresponding IP addresses. It is its only work. We can use it using the nslookup command to chek=ck your DNS server.

Default GateWay

It is the IP address of the Router in a LAN network through which data packets are sent to other networks.

It is the device which connects your LAN to other networks and is 'Default' because it is the first option looked upon when exiting.

Simplex Mode

One node can only send and other can only receive through the channel. Example: monitor output.

Half-Duplex Mode

Both nodes can send and receive but in turns. Example: walkie-talkie.

Full Duplex Mode

Sending and receiving is simultaneous. Example: phone calls.

Digital-to-Digital Conversion

Conversion of digital data to analog signals for transmission. Types: Unipolar, Polar, Bipolar.

UniPolar [NRZ]

1 → +V, 0 → 0V. Concept: Only one polarity is used.
Pros: Simple, Cheap.
Cons: DC component needed, Poor Sync.
Example: TTL circuits.

Polar

Uses positive and negative voltages, thus has three levels: 1 0 -1. Types: NRZ, RZ, Manchester.
Pros: Better Sync, No DC Component needed.
Example: Ethernet, USB.

BiPolar

Eliminates DC problem, maintains syncing.
Types: AMI, Pseudo-Ternary.
Example: T1/E1 lines.

BiPolar [AMI]

There are three levels: +, 0, -. But the 1 is represented alternatively by + and - voltages. While 0 is by 0V.

BiPolar [PsuedoTernary]

It is the same as AMI but here 1 is treated 0 and 0 is treated as 1.

Overall Summary

Common Terms

Bandwidth

Higher bandwidth → higher transmission rate.

Interference

Disturbance by unwanted electromagnetic signals.

Transmission Impairment

When received signals differ from original due to attenuation, distortion, or noise.

Attenuation

Loss of signal strength over distance.

Distortion

Loss of data due to frequency differences.

Noise Interference

Addition of unwanted signals.

Guided / Wired Media

Physical cables for data transmission (Bounded Media).

Twisted-Pair Cable

Most used in telecommunication and Ethernet. Types: STP, UTP.

RJ Connectors

Family of connectors for telephone and Ethernet wiring.

Coaxial Cable

Used for data, video, voice. Expensive, multiple layers to reduce interference.

BNC Connectors

Most common connector for coaxial cable.

Optic Fiber Cable

Glass strands transmit light pulses. High speed, long distance. Used in global Internet backbone.

Unguided / Wireless Media

Also called Air Media. Uses electromagnetic waves.

Radio Waves

Low frequency, penetrate walls. Used in radio, walkie-talkies. 20kHz – 300Hz

Microwaves

Straight line travel. Used for cellular, Wi-Fi, 3G/4G/5G. 1GHz – 1000GHz

Infrared Waves

High frequency, blocked by objects. Used in remote controls, night vision, motion detection. 300GHz – 400THz

Reading IPv4 Address

Network Part

It is the part of the IP which does not change in a network and identifies the network of computer.
192.168.32.225

Host Part

It is the part which identifies the device in the network and two devices in a network have different Host parts but same Network Part.
It may vary and can be known using Subnet Masks.
192.168.32.225

Subnet Masks

It is what tells that which is Host Part and which is Network Part. It can be also used to determine size of a network.

255.255.255.0 Usually for Private or Local Area Networks 255.255.0.0 Usually for Bigger networks like MAN

The 0 part will be Host Part in the IP Address. And 255 will be the Network Part in IP Address.

IP Classes

127.0.0.0 to 127.255.255.255 is a range of Loop-Back IP's.

Class A IP

These are like WAN having significant Range: 1.0.0.0 to 126.255.255.255. Default Subnet Mask: 255.0.0.0.

Number of Networks: 126, Number of Host 16 Million +
Used by: Very large organizations, ISPs, or backbone providers.

Class B IP

These are like MAN having lesser Range: 128.0.0.0 to 191.255.255.255. Default Subnet Mask: 255.255.0.0.

Number of Networks: 16,384 Hosts: 65,000+
Used by: ISPs, government agencies like NASA or ISRO.

Class C IP

These are your common LAN or PAN with low Range: 192.0.0.0 to 223.255.255.255. Default Subnet Mask: 255.255.255.0.

Number of Networks: Over 2 million Hosts: 254
Used by: Small organizations and local networks.

Class D IP

Range: 224.0.0.0 to 239.255.255.255.

These are Reserved Multicasting IP Addresses used by service providers or broadcasters. It does not require a subnet mask since multicasting doesn’t rely on host-specific communication — the data is broadcast to multiple recipients simultaneously.

Class E IP

Range: 240.0.0.0 to 255.255.255.254.

These do not need a subnet mask and are Reserved for Research and Development purposes by IANA.

Loopback IP

Range: 127.0.0.0 to 127.255.255.255.

These IPs are used for communication within your own machine.

Practical Uses

• Local testing — Run a local web server (e.g., localhost:3000) to test code without putting it on the internet.
• Networking checks — Pinging 127.0.0.1 confirms your TCP/IP stack is working.
• Internal communication — Apps communicate on the same machine without external traffic.
• Security isolation — Services can bind only to 127.0.0.1 to ensure they aren’t publicly accessible.

These addresses are not meant for networking but are used to maintain internal security and testing on your own system.

Limited Broadcast Address

Address: 255.255.255.255

This is a Reserved IP Address for Limited Broadcast — it refers to "everyone" on the local network. It’s used to broadcast messages to all hosts on a LAN. It is not a subnet mask or a valid assignable IPv4 address.

Common Uses

• DHCP Discover — When a device joins a network without an IP, it sends a broadcast to 255.255.255.255 asking for a DHCP server.
• Wake-on-LAN / Network discovery — Used for tools that need to reach all hosts locally.
• Diagnostics — Network troubleshooting and broadcast testing.

APIPA (Automatic Private IP Addressing)

Range: 169.254.0.1 to 169.254.255.255
Subnet Mask: 255.255.0.0 (/16)

When a computer fails to contact a DHCP server, it automatically assigns itself an IP in this range using APIPA. This allows limited local communication without internet connectivity.

IP to Binary

IPv4 to IPv6