Wireless Networks, NOS & Security
Enterprise Wireless Access Points (WAPs), WPA2/WPA3, Certificate Authorities, DHCP DORA process, and 1G-5G cellular evolution.
1. Enterprise WAPs vs. Home Wireless Routers
Home / Small Office
Home Wireless Router
Combines a router, basic 4-port switch, and Wi-Fi access point into one box.
- Capacity: Max 15 to 20 devices
- External whip antennas
- Powered via standard wall AC plug
Enterprise Grade Standard
Enterprise Ceiling Access Points
Dedicated ceiling units (e.g. Cisco Aironet, Ubiquiti UniFi) connected to centralized WLAN controllers.
- Capacity: 250 to 500 simultaneous high-speed users
- Internal multi-directional MIMO antennas
- Powered via Power over Ethernet (PoE) from network switch
2. DHCP 4-Step DORA Allocation Sequence
Dynamic Host Configuration Protocol (DHCP) automatically assigns IP addresses, subnet masks, default gateways, and DNS servers to client nodes:
1. Discover (Client $\rightarrow$ Broadcast)
Client sends a UDP broadcast (`255.255.255.255`) requesting an IP address.
2. Offer (Server $\rightarrow$ Unicast/Broadcast)
DHCP server offers an unassigned IP address lease option.
3. Request (Client $\rightarrow$ Server)
Client formally requests the offered IP lease.
4. Acknowledge (Server $\rightarrow$ Client)
Server confirms lease parameters (IP, Subnet Mask, Gateway, DNS).
3. 1G to 5G Mobile Telecommunication Generations
Cellular Telecommunication Evolution Properties
Gen Tech Focus Key Features / Speeds
1G Analog Telephony Voice calls only, zero digital data
2G Digital GSM / SMS Text messaging (SMS), basic digital encryption
3G Mobile Broadband Smartphones, email, basic web browsing (~2 Mbps)
4G LTE / High Speed HD Video streaming, cloud applications (~100 Mbps)
5G Ultra-Low Latency / AI Millimeter wave, IoT, smart cities, Gigabit speeds