SUNYNet Technology Services

SUNYNet Current Architecture

Case 5:   Intranet on a single T1 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 simultaneously and can be configured to give preferred handling to the intra for a similar example using AT&T). The intranet line is capable of handling both intranet traffic (red dotted line) and Internet traffic (blue dotted line) net traffic. In this case, however, the campus has chosen to keep its Internet traffic separate from the intranet. The intranet line is set for an appropriate port speed between 128K and 1.5Mbps, based on level of intranet usage.(see Case 6 for a similar example putting some Internet on the intranet line).

Because the campus has chosen not to merge internet and Intranet on one line, it does not need to activate, or pay for, CoS (Class of Service) with AT&T. Even without being a CoS subscriber, the campus may mark outgoing intranet packets to allow their traffic to receive priority as it traverses the access lines of campuses that do subscribe to CoS. SUNYNet can do this marking in its campus (tan) router.

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 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. 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. It is fully capable of handling packets to any Internet address, not just those for the intranet, but the return route will always be through the general Internet routers because they are announcing the campus's IP addresses.

All of the public IP address space for the campus will be announced to the Internet by their ISP.