Static Routing

Updated: February 13, 2009

Applies To: Windows 7, Windows Server 2008 R2

A static routed IP network does not use a routing protocol such as Routing Information Protocol (RIP) to communicate routing information between routers. All of the routing information is stored in a static routing table on each router. You need to ensure that each router has the appropriate routes in its routing table so that traffic can be exchanged between any two endpoints on the IP network.

A static routed IP environment is best suited to a small, single-path, static IP network:

  • A small network is defined as 2 to 10 networks.

  • Single-path means that there is only a single path for packets to travel between any two endpoints on the network.

  • Static means that the topology of the network does not change over time.

The disadvantages of static routing are:

  • No fault tolerance

    If a router or link goes down, static routers do not sense the fault and inform other routers of the fault. While this is a concern on large, corporate networks, a small office (with two routers and three networks based on LAN links) does not go down often enough to justify deploying a multipath topology and a routing protocol.

  • Administrative overhead

    If a new network is added or removed from the network, routes to the new network must be manually added or removed. If a new router is added, it must be properly configured for the routes of the network.

Perform the following steps to deploy static routing:

  1. Draw a map of the topology of your IP network that shows the separate subnets and the placement of routers and hosts (non-router computers that run TCP/IP).

  2. For each IP subnet (a cabling system bounded by one or more routers), assign a unique IP network ID (IPv4) or prefix (IPv6).

  3. Assign IP addresses to each router interface. It is a common industry practice to assign the first IP addresses of a given IP network to router interfaces. For example, for an IPv4 network ID of 192.168.100.0 with a subnet mask of 255.255.255.0, the router interface is assigned the IPv4 address of 192.168.100.1.

  4. For peripheral routers, configure a default route on the interface that has a neighboring router. The use of default routes on peripheral routers is optional.

  5. For each non-peripheral router, compile a list of routes that need to be added as static routes to the routing table for that router. Each route consists of a destination network ID and either a subnet mask (for IPv4) or a prefix length (for IPv6), a gateway IP address, a metric (number of router hops to reach the network), and the interface to be used to reach the network.

  6. For non-peripheral routers, add the static routes compiled in step 5 to each router. You can add static routes by using the RRAS MMC snap-in. For more information, see IPv4 - Static Routes or IPv6 - Static Routes.

  7. When your configuration is complete, use the ping and tracert commands to test connectivity between host computers so that all routing paths are checked.

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