Microsoft KB Archive/105155

= Explanation of Seed Router Roles in AppleTalk Internets =

Article ID: 105155

Article Last Modified on 10/31/2006



This article was previously published under Q105155



SUMMARY
The AppleTalk world includes different kinds of routers, all of which forward data from one physical network to another. Seed routers provide a unique additional service: they initialize and broadcast information about one or more physical networks that tells other routers where to send each packet of data. Each physical network must have at least one seed router, and it must be started first in the network to assure that all other routers are initialized correctly.

MULTIPLE SEED ROUTERS
A LocalTalk network can have more than one seed router, and in some cases multiples are recommended. For one thing, multiple seed routers increase network reliability. For another, administrators for wide area networks (WANs) can install several seed routers and make them independent so that users in one area don't have to wait for seed routers in remote areas to start.

Multiple seed routers must have identical seeding information. If a Windows NT Advanced Server seed router at startup detects another network seed router with different information, the first router's information is used to seed the network, and the second router is referenced in an "Invalid network range" event written in the Windows NT Advanced Server event log. LAN Manager Services for Macintosh does not inform you of this; the Apple Internet router simply refuses to start and reports that there is another seed router with different information.

SEEDING INFORMATION
There are three types of seeding information:


 * A network number or range associated with each physical network. A network number is a unique identifier for an AppleTalk physical network (any number from 1 through 65,279) which routers use to send incoming data to the correct physical network. It is highly recommended that you plan your AppleTalk Internet first. For information on how, see Chapter 3 of "Windows NT Advanced Server Services for Macintosh" or Chapter 2 of the "LAN Manager Services for Macintosh Installation Guide."
 * The zone list associated with each physical network. A zone is a logical group of networks that allows the Internet to be controlled in segments, rather than as a single entity. LAN Manager and Windows NT domains are groups of users; AppleTalk zones are groups of machines. In LocalTalk networks, each physical network can be associated with only one zone. AppleTalk Phase 2 does not observe a strict relationship between zone names and network numbers, so two nodes in different zones can have the same network number.
 * The default zone for the network, into which all AppleTalk devices fall if they do not specify otherwise. Each Macintosh can select which zone to belong to. The KB article "How to Enable Seed and Non-Seed Routing" explains how to set up zone assignments properly.

Remember: seed routers must be started (booted) before any other Internet routers and ALL of the above seeding information must be the same for all seed routers in the Internet.

Additional query words: sfm 1.0a appletalk osi concepts seed router

Keywords: KB105155

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