5.12 EGP

The Exterior Gateway Protocol (EGP) is an exterior routing protocol that is supported by the TCP/IP software. Exterior routing protocols exchange information between different Autonomous Systems (ASs). The local EGP gets the information about its own AS from the local Interior Gateway Protocols (IGPs). Usually, exterior routing protocols are used only when different companies or commercial services are being connected.

The information EGP receives from the IGP must be explicitly configured. The exterior routing protocol shares only the information specified in the outgoing route filters. This is desirable because you generally want to limit the information exchanged between different ASs.

You can configure EGP using INETCFG.

  1. Load INETCFG, then select Protocols > TCP/IP > Expert Configuration Options.

  2. Select EGP > Enabled.

  3. Select EGP Configuration, then configure the following parameters:

    • Autonomous System: Specify the autonomous system number. It identifies the autonomous system to which the router belongs. The router establishes an EGP neighbor relationship with routers in other autonomous systems.

    • Maximum neighbours to Acquire: Specify the maximum number of concurrent EGP neighbors with which this router can exchange EGP network reachability information.

    • Neighbour List: Select this field to add, modify, or delete EGP neighbors. This router attempts to establish a relationship with the configured EGP neighbors to exchange network reachability information. Press Insert, then configure the following parameters:

      Neighbor's Address: Press Insert to display a list of symbolic hostnames from the sys:\etc\hosts file. Select a host here or enter the address.

      Neighbor’s Autonomous System: Enter the number of the autonomous system to which this EGP neighbor belongs. The router is able to be a neighbor with the EGP peer only when the router and the EGP peer are in different autonomous systems.

  4. Press Esc until you are prompted to save your changes, then select Yes.

  5. Press Esc to return to the Internetworking Configuration menu.

  6. If you want these changes to take effect immediately, select Reinitialize System > Yes.