Seeding State

Seeding refers to an AppleTalk router's ability to teach other routers on a connected network about the network configuration. A non-seed router (often called a learning router ) learns its configuration information from a seed router (often called a configured router ). The Network Range and Zone option (found in the AppleTalk Bindings configuration screen in NIASCFG) enables you to configure either a seed or a non-seed interface.

At least one router on a network must be a seed router. If the network is an extended network, a seed router is configured with a network number range and a zones list for the network. If the network is a nonextended network, a seed router is configured with a single network number and a single zone name for the network. Non-seed routers on the network learn this network number range and zone information dynamically from the seed router.

The seeding state option applies individually to each router interface. One interface can be specified as learning , whereas another can be specified as configured . If you configure an AppleTalk router interface as a learning interface and there is no seed router on that cable, the AppleTalk router remains inactive on that interface until it receives configuration information from a seed router on the network.

Benefits of the Seeding State Option

The seeding state option provides these benefits:

• When you specify the non-seed option for an interface, the router obtains a network configuration consistent with other routers connected to that network.
• If you use one seed router and have learning interfaces in all other AppleTalk routers connected to the network, you can later change the network or zone configuration much more easily. Instead of reconfiguring all routers on a network, you can bring down all routers and reconfigure only the seed router. After the old network and zones lists are aged out from the internetwork, restart the reconfigure routers. The seed router updates the other routers with the new information.

How the Seeding Feature Works

AppleTalk routers use RTMP to distribute network configuration information. Every 10 seconds, each AppleTalk router broadcasts RTMP packets containing information about networks, including the directly connected ones. Other AppleTalk routers receive the RTMP packets and use the information to build and maintain a complete view of the AppleTalk internetwork.

When you configure the AppleTalk router with one or more learning interfaces, it uses information received in the RTMP packets to acquire the network number on a learning interface. Then it sends a request for that network's zone information.

If you configure the network and zone information in the Novell Internet Access Server 4.1 routing software, the AppleTalk router tries to validate the configured information against advertised information from any other routers on the network. If there is a conflict, the router does not bind to the LAN card and an error message appears, indicating whether the conflict is in the network number, the default zone, or the zones list. This error message also displays the address of the router from which it received conflicting information. If such a conflict occurs, determine what the correct network and zone information should be, then use NIASCFG to reconfigure the router.