Within the Washington School District, a Local Area Network (LAN) is to
be designed for each school. With these networks designed, the District
has
asked that all schools be linked together into one large Wide Area Network (WAN). So that the various tasks involved in constructing this WAN can be
accomplished in an organized fashion, this document is has been written
to summarize the many things which the Washington School District requires
in its WAN.
Individual schools connected to the WAN are to be serviced out of one of three regional WAN hubs located at the Phoenix District Office/Data Center, the
Greenway Service Center, and the Shaw Butte School. Individual schools are to connect to these hubs through T1 data lines leased from a service provider. In
addition, these three regional hubs are to use T1 lines between them for fast data delivery at a rate of 1.544 Mbps. All of these 36 lines will use PPP as the
underlying encapsulation format. An extra line will extend from the District Office/Data Center out to a next hop router on the Internet. This line will also be a T1
line, but it will run Frame
Relay instead of PPP.
The Washington WAN will run on a two layer hierarchical model. At the access layer are individual schools such as Acacia, R. E. Miller, Royal Palm and
others. Higher up at the core layer are the three district WAN hubs connected in a point to point manner. Also at this layer is the WAN?s public backbone
network, a small network consisting only of a DNS server and an E-Mail server. These exist on the public backbone because all users throughout the District will
be accessing the same services from these same two computers. Finally, at the core layer, the Access Control Lists (ACLs) will be installed to prevent unauthorized
access of the District WAN by users on the global Internet.
In addition, the District has asked that the WAN be designed with an eye towards future growth. Towards that end,decisions have been made to insure that
the speed of the WAN connections can be upgraded without reinstalling the physical cabling. For one, the 2621 modular access router at the Acacia school has 2
slots, each with an integrated CSU/DSU WANcard. Each slot is designed to connect to a T1 line, although only one slot will be used in the present installation.
The other slot will be available for backup or to be brought up for load sharing and an increase in throughput. However, if both slots are brought up, no backup slot
will exist unless the router is upgraded.
Although most of the WAN connections will run on T1 lines, there is one school that requires a different kind of access. The Community School, serviced
out of the Shaw Butte regional hub, requires only part time connectivity to the WAN. Therefore, it will use an ISDN connection. A few devices will need to be
installed for this school so that it can accommodate an ISDN connection.
Exact details on the ISDN installation in the Community School are available
here.