Internet Service Provider (ISP)

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Internet service providers (ISPs) construct and maintain the individual networks comprising the internet.

• ISPs are assigned IP addresses by ICANN

Three Tiers of ISPs

Tier 1

Tier 1 ISPs consist of high-speed, high-capacity, international WANs that are typically operated by large communication companies

• top of the ISP hierarchy
• least common
• serves as backbone of internet

Tier 2

Tier 2 ISPs and tier 1 are networks of routers that collectively provide the internet’s communication infrastructure

• more common and regional in scope

Tier 3

Tier 3 ISPs are typically independent internets, sometimes called intranets, operated by a single organization that supplies internet access to homes and businesses.

• aka access ISPs

Hosts, or end systems, are devices used to connect to the access ISP

• E.g., PC, laptops, smartphones, cameras, automobiles, and home appliances
• connect to larger networks via
  • telephone lines
  • cables
  • satellites