The Princeton University campus network is connected to both the Internet (a world-wide collection of inter-connected networks that all use the TCP/IP protocols) and to Internet 2 (a consortium of over 207 universities working in partnership with industry and government to develop and deploy advanced network applications and technologies). The connections to the Internet and I2 provide the campus with a vast array of services and information including access to the world-wide web and electronic mail.
The structure of the campus network and its interconnection to the Internet and I2 are technically complex, but the underlying principle is that each host uses a unique IP address to establish communication with another device. This is similar to knowing someone's telephone number. The campus host registration process is used to assign a unique IP address to each Princeton host.
Because IP addresses (like telephone numbers) are difficult to remember, the Domain Name Server (DNS) function allows a machine to translate a host name into an IP address.
Once a host is configured with its IP address, it can use the DNS service to locate and then establish communication with campus or Internet servers such as www.princeton.edu or www.yale.edu . If the server being accessed is not located on the campus, the data travels over the Internet (or Internet 2).
Access to the Internet and Internet 2 is obtained from an Internet Service Provider (ISP). The total amount of data that can flow to or from the Internet and the campus is limited, in part, by the speed of the physical connection joining the campus to the ISP. As of September 2006, the University's total bandwidth to the Internet is 1000 megabits per second (Mbps) and to Internet 2 is 500Mbps for an aggregate of 1500Mbps.
In order to provide high availability to the Internet, the campus network is connected to two Internet providers: US LEC (a.k.a. Fastnet) and Patriot Media . Having two ISP connections sharing the campus Internet traffic, ensures that a failure of one ISP does not disable campus access to the Internet. Each ISP connection opearates at 500Mbps.
Princeton University is also a member and participant in Internet 2 which is a very high-speed network supporting communication and research among I2 members. Many educational, government, and research organizations are members of Internet 2. Internet 2 is similar in structure to the Internet (both use TCP/IP), but I2 provides significantly higher communication speed end-to-end which improves service and enables new applications. US LEC was able to provided Princeton University with the opportunity to join a regional I2 Gigapop, MAGPI. MAGPI connects directly to the Internet 2 network, Abilene.
Because the links to the Internet and I2 are shared by all campus applications, the utilization of the various ISP connections is closely monitored. The correct, efficient, and reliable operation of the campus network and its connectivity to the Internet is the primary goal of all the OIT groups responsible for the networking.