Intranet Subnets and Gateways

The more complex the network is, the more benefit will be derived from thoughtful planning. Any network protocols used, in addition to TCP/IP, the presence of DHCP servers to automatically assign IP addresses, and WINS servers for computer name resolution, will affect the network design and performance.

Because of these factors, some locations with sufficient technical expertise may choose to implement IP networks with specific subnet sizes to take advantage of particular configurations.

In a networking environment that only uses the TCP/IP protocol, subnetting can be used to limit which workstations can access particular servers and which computers receive network broadcasts. If it is desired that all computers can access all servers, that can also be achieved by appropriate use of subnets.

Many smaller schools have been successful operating with 3 gateways and 3 small blocks of IP addresses. Most of those schools will be operating in the future with 1 subnet and 1 gateway for one large block of IP addresses. Larger schools with over 300 computers probably need to consider using multiple subnets. All the addresses do not have to be sequentially assigned to actual computers initially.

A location may reserve ranges of addresses based on the instructional use and/or physical location of the computers. This may result in fewer than 1/8 of the IP addresses being initially used, but allows for a logical process of assigning IP addresses to additional computers as they are added to the school network.

For example, in a school with 1000 students, it may be determined that the networking needs of the school would be better met by creating larger subnets with fewer gateways, or smaller subnets with more gateways.

Possible gateway / subnet configurations include:

16 gateways with 254 addresses each
8 gateways with 510 addresses each
4 gateways with 1022 addresses each
2 gateways with 2046 addresses each

Changes in subnet sizes require router configuration changes, and must only be done after contacting the WVDE OTIS to request router reconfiguration.

Assistance in determining subnet masks and the range of IP addresses to be included in alternative subnet sizes may be requested of the RESA's or the WVDE OTIS.

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