What we do
The SUNet backbone consists of two backbone switch/routers which provide interconnection between a set of routers which serve users networks. The user routers make use of virtual networks (VLANs) on the routers to provide individual router interfaces for each network which can then be distributed using ethernet trunking technology. Each user router is connected to both backbone routers to provide reliability. The only protocol routed on SUNet is the Internet Protocol (IP). All of the links at the backbone level are currently deployed using 1-Gigabit ethernet. User networks on-campus are connected using either 1-Gigabit or 100-megabit ethernet, depending on the equipment at the user's building entrance.
For off-campus connections in the Palo Alto area, it is possible to make high-speed fiber-optic connnections 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 (aka ATT/SBC/Pac*Bell). Typically these lines run at DS1 (T1) speeds, around 1.5 megabits per second. For home connections, SCS has a Stanford-managed DSL offering, which provides the home users a direct connection to SUNet.
The SUNet backbone can be considered to have four areas. Three areas are for the user network routers and the fourth is the "border" area where connections to the off-campus internet are made. For user networks, there is the main campus area, the School of Medicine area and the student residential area. Routers within an area exchange IP packets directly, using the switching capability of the backbone equipment. Between areas, the IP traffic utilizes the routing capability of the backbone.
Connectivity to the Internet and Internet2
All connections to the internet off-campus are currently 1-Gbps. There is one primary commercial ISP with a backup connection to CENIC's ISP service. There are two additional connections to the CalREN2 networks run by CENIC. The CENIC High-Performance Research (HPR) network provides high-bandwidth connections among all the California Internet2 participants and to the Abilene network for national Internet2 connectivity. All systems connected to SUNet have access via the HPR network to other institutions which are connected to CalREN2 or Abilene.
The second network run by CENIC is the Digital California (DC) network. This provides internet connectivity to most of the community colleges in California as well as all the campuses of the California State University (CSU) system (note that some CSU campuses also have HPR connectivity). In addition, the DC network provides a connection to each county in California so they can connect their K-12 schools. CENIC also provides internet peering over the DC network. All systems connected to SUNet also have access to any routes receivied from the DC network.
Future backbone evolution
During the last half of 2006 and continuing through 2007, Networking Systems will be upgrading the backbone to use 10-Gigabit per second ethernet links on campus. This will require replacing all the user network routers as well as upgrading the backbone switch/routers. It is likely that the connection to CENIC's HPR network will also be upgraded to 10-Gbps during this timeframe. User network connections will continue to be provided at 1-Gbps but backup routers will be installed to provide increased reliability.
More Information
For additional details about Departmental Network Engineering, contact Dave Macia.
