Levels of Internet Connectivity

• Level 1 - Access through a gateway
• Level 2 - Access via modem to host connected to network
• Level 3 - Direct Internet Access

Level 1 Connectivity

• Services are limited to what gateway supports
• Examples
  • Department's / University's Computer Network.
  • America On-Line, Compuserve, Prodigy, etc.
  • Sub-network is not really on the Internet but has access to it in accordance with traffic allowed through gateway

Level 1 Gateway Connection

Level 2 Connectivity

• Services are limited to what the connected-to host (H₂) provides
• Everything is accomplished through the H₂
• File transfers from Internet to H₁ require two downloads: Internet to H₂ and H₂ to H₁
• Level 2 connectivity is the most prevalent of Internet access

Level 2 Internet Connection

Level 3 Connectivity for Consumer

• Some local companies provide Serial Line Interface Protocol (SLIP) or Point-to-Point Protocol (PPP) Internet access

Level 3 Internet Connection