The individual networks comprising the internet are constructed and maintained by internet service providers (ISPs). ISPs are classified in tiers depending on the role they play in the overall internet structure.
Tier-1 ISP
Tier 1 ISP:
Position: At the top of the ISP hierarchy. Rarity: The least common type of ISP. Role: Serves as the backbone of the internet. Composition: Consists of high-speed, high-capacity, international Wide Area Networks (WANs). Operators: Typically operated by large communication companies.
Tier-2 ISP
Tier 2 ISPs:
Prevalence: More common than Tier 1 ISPs. Scope: Regional in nature. Function: Along with Tier 1 ISPs, they form a network of routers. Role: Collectively provide the internet's communication infrastructure.
Tier-3
Tier 3 ISPs (Access ISPs):
Nature: Typically independent internets, often referred to as intranets. Operators: Operated by a single organization. Purpose: Supply internet access to homes and businesses. Connection Devices: Known as end systems or hosts. Examples of Devices: Includes PCs, laptops, smartphones, cameras, automobiles, and home appliances. Connecting Technologies: Variety of technologies used for connection. Common Technologies: Include telephone lines, cables, and satellite.
Architecture of the Internet
