Intranet Network Planning

As this is read, keep in mind that the number of computers and network devices in the West Virginia K-12 schools is growing at a steady or increasing rate. Five years ago, few of us knew what the technology in schools for the 1999 - 2000 term would be. Now, we are trying to look at least 5 more years into the future by providing an IP addressing plan that may look extravagant today, but may be barely adequate in 2005.

The WVDE OTIS (West Virginia Department of Education, Office of Technology and Information Systems) has assigned large blocks of IP addresses to the RESAs, counties, and schools.

Many factors may affect the way that individual IP addresses are assigned at each location. The process of assigning IP addresses to individual computers at the building level may be facilitated by explaining some of the rationale used in developing the statewide private IP addressing plan.

A note about some terminology used: a "block" of IP addresses may be more appropriately called a "subnet." Each block or subnet has one gateway address, and the number of host IP addresses is determined by a subnet mask. The size of subnets using 168.216.x.x addresses is 30 hosts, the size of subnets using 10.x.x.x address can be 254 or 1022 hosts or more, depending on the subnet mask.

School and RESA routers are currently being changed so that they support routes for 10.x.x.x addresses and 168.216.x.x addresses. This means that each school router is connected to the North or South POP and to the respective RESA by the private intranet route addresses and also by the existing 168.216.x.x addresses.

By doing this, the schools and offices can change the IP addresses on their servers and workstations at any time after their specific router has the 10.x.x.x WAN routes added. At some later time, the 168.216.x.x routes will be removed from the routers, which requires no involvement by the schools. All 168.216.x.x IP addresses will be used on the PIX firewalls.

For most schools, the change is transparent. WVEIS and Internet connections will continue to function as before. The final process to complete the transformation to a private K-12 intranet will be the complete readdressing of every computer and device with a 168.216.x.x address to a 10.x.x.x address.

The Internet servers (HTTP, FTP, POP3/SMTP, TELNET, etc.) will be the computers that need to have the new IP address assigned approximately at the same time the router is changed so that the PIX servers at the POP's can be configured to make those Internet servers accessible or visible to the Internet.

Any other computer in the k12.wv.us domain will not be accessible from the Internet, but could be accessible from within the k12.wv.us intranet if it is configured as an intranet server.

Each school is assigned a minimum of 1022 total IP addresses. (Schools with over 300 students will get additional addresses so that the total number of IP addresses is about 4 times the number of students.)

Each gateway address will be the first IP address in the subnet, ending in the number 1.

The default subnet mask will be 255.255.252.0.

In order to allow for efficient network management and to receive the best support to resolve networking problems, a consistent addressing scheme at each location is necessary.

Addresses ending with the numbers 5 - 9 are to be assigned to Internet servers. If a location has a web server it will end with the number 5.

For example:
10.45.0.5 could be a web server
10.45.0.6 could be a server that supports school management functions.
A school that has no Internet servers will reserve 5-9 in case Internet servers are added later.

Addresses ending with the numbers 10 - 29 are to be assigned to managed hubs and switches, LAN servers, networked printers and other network devices.

Addresses ending with the numbers 31 - 254 are to be assigned to individual workstation computers.

Addresses ending with the numbers 1 - 4 are reserved for use by the WVDE OTIS and NOC, and addresses ending with the number 30 is reserved for temporary use by technicians to troubleshoot and test networks.

The benefit of all locations using this consistent numbering scheme is that network monitoring programs can be set to alert network managers when problem exist on certain ranges of IP addresses. Since IP addresses with numbers ending in 1 - 30 are assigned to devices that affect the network, network managers will be able to distinguish between network critical failures and individual workstation problems.