Gateway considerations

Take these actions before configuring your gateway.

Before you configure the gateways for your network, you must first do the following:

  1. Consider the number of gateways to use.
    The number of gateways you need to configure will depend upon:
    • The number of networks you want to connect.
    • How you want to connect the networks.
    • The level of activity on the connected networks.

    For example, suppose users on Network 1, Network 2, and Network 3 all need to communicate with each other.

    Figure 1. Simple gateway configuration
    Simple gateway configuration
    This illustration contains three network clouds numbered one, two, and three. Networks one and two are connected with gateway A. Networks two and three are connected with gateway B.

    To connect Network 1 directly to Network 2, you would use a single gateway (Gateway A). To connect Network 2 directly to Network 3, you would use another gateway (Gateway B). Now, assuming the proper routes are defined, all the users on all three networks can communicate.

    However, if Network 2 is very busy, communication between Network 1 and Network 3 might suffer unacceptable delays. Furthermore, if most of the inter-network communication occurs between Network 1 and Network 3, you might want to connect Network 1 directly to Network 3. To do this, you could use an additional pair of gateways, Gateway C (on Network 1) and Gateway D (on Network 3), with a direct connection between these two additional gateways. This may be an inefficient solution, however, because one gateway can connect more than two networks.

    A more efficient solution would be to connect Gateway A to Gateway B directly, as well as to Network 2. This would require a second network adapter in both Gateway A and Gateway B. In general, the number of networks you connect through a single gateway is limited by the number of network adapter cards the gateway machine can support.

  2. Decide on the type of routing to use.

    If your network is small, and its configuration rarely changes, you probably want to use static routing. But if you have a large network whose configuration changes frequently, you probably want to use dynamic routing. You might decide to use a combination of static and dynamic routing. That is, you might want to give static definitions to a few specific routes, while allowing other routes to be updated by the daemons. The static routes you create are not advertised to other gateways and are not updated by the routing daemons.

  3. If you are using dynamic routing, choose the routing daemon according to the type of gateway you need and the protocols your gateway must support.
    If the gateway is an interior gateway, and only needs to support RIP, choose the routed daemon. If the gateway must support any other protocol, or is an exterior gateway, choose the gated daemon.
    Note: Unpredictable results can occur if the gated and routed daemons run on the same host at the same time.