The SUNet backbone consists of two backbone switch/routers and ten operational zones. Each operational zone consists of a redundant pair of operational zone routers, a redundant pair of operational zone firewalls, and a redundant pair of operational zone distribution switches. Each operational zone services 30 to 50 departmental networks. In order to further enhance availability, the redundant network equipment is geographically dispersed in multiple electronic communications hubs around campus. All connections between the operational zone equipment, as well as from each operational zone to the backbone routers, operate at 10Gbps. Departmental networks connect into the operational zone at 1Gbps.
For off-campus connections in the Palo Alto area, it is possible to make high-speed fiber-optic connections by contracting for the use of the fiber plant run by the City of Palo Alto Utilities. Where fiber is not available, connections back to campus can be made using serial lines provided by the phone company (e.g., ATT/SBC/Pac*Bell). Typically these lines run at DS1 (T1) speeds, around 1.5 megabits per second. For home connections, IT Services has a Stanford-managed DSL offering, which provides the home users a direct connection to SUNet.
The SUNet backbone connects to CENIC, Internet2 HPR, DC, NLR, and the commercial Internet. The SUNet backbone has a 10-Gigabit connection to the NRENs (National Research and Education Networks) via the HPR (High-Performance Research) network run by CENIC (Corporation for Educational Networks in California). Stanford has multiple 1-Gigabit connections to CENIC, which provides access to both Internet2 and NLR (National Lambda Rail) networks, both of which run at 10-Gigabit for educational institutions in California. Stanford also has a commercial Internet connection provided by Cogent ISP for traffic destined to locations not reachable via the CENIC peering connections.