158 .235 Lecture Notes - Asynchronous Transfer Mode, Virtual Private Network, Packet Switching
Document Summary
Mans and wans are typically built by using leased circuits from common carriers such as chorus ltd. To create point to point links between organizational locations. Ansi standard for optical fiber transmission in gbps range. Enable multiple connections to exist simultaneously between computers over the same physical circuits. Permanent virtual circuit common, established for long duration. Switched virtual circuit established dynamically on a per call basis. Provides packet switching service, type of service protocol. Provides the equivalent of a private packet switched network over the public internet. Uses virtual circuits (tunnels) that run over the public internet, yet appear to be private networks to the user. Encapsulates the packets sent over these circuits using special protocols that also encrypt the ip packets. Disadvantages unpredictability of internet traffic, lack of standards for vpns. Intranet vpn provides virtual circuits between organization offices over the internet. Extranet vpn same as intranet vpn, but vpn connects several different organizations.
