Overview
This lecture covers different types of internet connectivity technologies, focusing on their advantages, limitations, and key characteristics relevant for home and remote site internet access.
Satellite Networking
- Satellite internet uses Earth-to-satellite connections, providing global access but at a higher cost.
- Typical satellite speeds are around 100 Mbps down and 5 Mbps up.
- Satellite connections often have high latency, traditionally about 0.5 seconds total, though new systems like Starlink reduce latency to 25–60 ms.
- Requires line of sight to the satellite and can be disrupted by weather (rain fade).
Fiber Optic Connectivity
- Fiber optic cabling uses light to transmit large amounts of data efficiently over long distances.
- More expensive than copper both in materials and equipment, and repairs are costly.
- Common for metropolitan area networks and increasingly available for home connections.
- Fiber often connects to a home, then converts to copper wiring inside.
Cable Broadband (DOCSIS)
- Cable internet uses the same coaxial cable as cable TV, supporting broadband (multiple frequencies for different services).
- DOCSIS (Data Over Cable Service Interface Specification) is the standard for data over cable.
- Typical speeds range from 50 Mbps up to 1 Gbps or more.
- Supports combined internet, TV, and voice services over one line.
DSL (Digital Subscriber Line)
- DSL uses standard telephone lines to provide internet, often called ADSL (asymmetric digital subscriber line) due to faster download than upload speeds.
- Common speeds are up to 200 Mbps down/20 Mbps up, depending on distance from the central office (max ~10,000 feet).
- Speed decreases as distance from the provider increases.
Cellular and Wireless Internet
- Cellular networks provide internet using mobile phone infrastructure; areas are divided into cells with antennas.
- Tethering connects one device to a phone for internet access; a mobile hotspot lets multiple devices connect via a phone.
- Wireless ISP (WISP) offers internet via an external antenna to remote locations without cable or phone lines.
- Wireless connections may use mesh 802.11, 5G, or proprietary systems, with speeds from 10 Mbps to 1 Gbps.
Key Terms & Definitions
- Satellite Networking — Internet connectivity via communication with orbiting satellites.
- Latency — Delay in data transmission between sender and receiver.
- Fiber Optic — Cabling that transmits data via light for high-speed and long-distance connectivity.
- Broadband — Multiple frequencies on a single cable for simultaneous data streams.
- DOCSIS — Data Over Cable Service Interface Specification, standard for cable internet.
- DSL (ADSL) — Digital Subscriber Line, internet over telephone lines, often with higher download than upload speeds.
- Tethering — Using a mobile device to provide internet to another device.
- Mobile Hotspot — Sharing a mobile device’s internet connection with multiple devices over Wi-Fi.
- WISP — Wireless Internet Service Provider, delivers internet wirelessly to remote areas.
Action Items / Next Steps
- Review differences between each internet technology and their use cases.
- Check which types of connections are available in your area for further study or project work.