Introduction to Networking
Every AWS resource (a server, a database, a load balancer) talks to others over a network. Later you will build your own private network in AWS, called a VPC. To design one, you first need the basics: what a network is, the devices that build it, and how IP addresses and ports find the right machine and service.
In this session
- Network vs networking
- PAN, LAN, CAN, MAN and WAN
- Network devices: NIC, hub, switch, router, firewall
- Protocols, IP addresses and port numbers
- How each idea maps to AWS
01Network vs networking
Every device needs a NIC (Network Interface Card) to join a network. In an office, the devices usually connect to a switch in the middle.
02Types of networks by size
03Network devices
| Device | What it does | Real-life comparison |
|---|---|---|
| NIC | connects one device to a network; has a fixed hardware MAC address | the door of your house |
| Hub | sends every message to all devices (old, slow, insecure) | a loudspeaker announcement |
| Switch | sends each message only to the right device inside a LAN (uses MAC addresses) | a receptionist handing each letter to the right person |
| Router | connects different networks, e.g. your LAN to the internet (uses IP addresses) | a post office sending letters between cities |
| Wi-Fi router | router + switch + wireless access point in one box | an all-in-one post office at home |
| Access point | adds Wi-Fi to a wired network | a wireless extension |
| Firewall | allows or blocks traffic by rules | a security guard at the gate |
04Protocols, IP addresses and ports
| Word | Meaning |
|---|---|
| Protocol | a set of rules for communication (grammar for computers) |
| IP (Internet Protocol) | the basic rules for moving data from one device to another using addresses |
| IP address | a logical address for a device: 32-bit (IPv4, e.g. 192.168.1.10) or 128-bit (IPv6) |
| MAC address | the physical address burned into the NIC |
IP address = building address; port = flat number. The IP address finds the right machine; the port number finds the right service (website, SSH, database) on that machine.
| Port | Service | Where you will use it |
|---|---|---|
| 22 | SSH: remote login to Linux | Day 10 |
| 80 | HTTP: websites | Day 12 |
| 443 | HTTPS: secure websites | everywhere |
| 3389 | RDP: remote desktop to Windows | Day 9 |
| 3306 | MySQL database | databases module |
05From your office to AWS
| Traditional | AWS equivalent |
|---|---|
| Office network (LAN) | VPC (Virtual Private Cloud) |
| Network segments | Subnets |
| Router | Route tables |
| Connection to the ISP | Internet Gateway |
| Firewall at the server | Security group (stateful) |
| Firewall at the network segment | Network ACL (stateless) |
| NIC | ENI (Elastic Network Interface) |
| Leased line between offices | Direct Connect or Site-to-Site VPN |
- Switch → MAC addresses, inside a LAN. Router → IP addresses, between networks.
- “Users can’t reach the website” → check the security group allows port 80/443.
06Summary
- Network = connected devices; networking = their communication.
- Sizes: PAN < LAN < CAN < MAN < WAN; the internet is the biggest WAN.
- Switch delivers inside a LAN; router connects networks; firewall allows or blocks.
- IP address finds the device; port finds the service (22 SSH, 80 HTTP, 443 HTTPS, 3389 RDP).
- AWS versions: VPC, subnets, route tables, internet gateway, security groups.
07Quick quiz
1. Which device delivers data only to the right PC inside a LAN?
2. Which device connects your office network to the internet?
3. A bank connecting its branches in one city uses a…
4. Port 443 is for…
5. In AWS, your private network is called a…