SUNYNet Technology Services

SUNYNet Current Architecture

Case 6:   Intranet on a single T1 combined with general Internet as a lower priority; Other ISP for general Internet
(see drawing, below)

Listing of Cases

Method of delivering Internet and intranet:
SUNYNet intranet service is built on a line to AT&T's Internet. The line terminates on campus in a router (the blue, cross-shaped box) that is owned and operated by AT&T. SUNYNet Operations also operates a router (tan, cross-shaped box) on campus. The campus's Internet requirements exceed the capacity of a single T1. To meet this need, they have chosen to use an ISP other than AT&T. (see Case 2 for an example of using AT&T). The intranet line is capable of handling both intranet traffic (red dotted line) and Internet traffic (blue dotted line) simultaneously and can be configured to give preferred handling to the intranet traffic. The campus has chosen to put some Internet traffic on the intranet line (see Case 5 for an example of keeping Internet off this line). AT&T offers a new feature that helps make this merging feasible. The feature, called CoS (Class of Service) tells the routers on both ends of the campus-to-AT&T link to give priority to specially identified traffic in both directions. This allows the line to run near capacity all the time without hurting response time on high priority (intranet) applications. This feature carries an additional monthly fee, but the campus justifies the expense because it gives inexpensive additional Internet bandwidth. Also, it allows the intranet line to be used for small, but important subnets, such as the Administration building, library, or some classrooms, giving them consistent response times.

Roles of the Routers:
Most LAN traffic is directed to the other ISP's Internet router (the orange, cross-shaped box). Specially identified IP traffic, including all intranet traffic, is directed to the SUNYNet router, which then marks authorized intranet traffic in one of three high priority categories. The top priority marking is applied to designated video and voice traffic, and the second highest to interactive applications such as business and library. Certain addresses or ports can be identified for better-than-average Internet performance if so desired. Wherever the application requires it, the router puts traffic into a "tunnel" (not shown graphically here) to make it secure (encrypted) or to control its flow over the AT&T network. Also, tunnels will be used for SUNY-to-SUNY DECNet traffic. The SUNYNet router hands packets to AT&T's campus router over an Ethernet cable. The AT&T campus router sends traffic into its core network (blue cloud) which delivers it to SUNY destinations, or to other AT&T Internet subscribers and Internet Service Providers worldwide.

Most of the public IP address space for the campus will be announced to the Internet by their primary ISP. Some subnets must be announced by AT&T so that the SUNYNet/AT&T service can carry some of the Internet load.