Apple Confidential
L we oe a ma
«6. Apple. AppleTalk
Internet Router Administrator’s Guide
Apple Confidential
@ APPLE COMPUTER, INC.
This manual and the software described in it are copyrighted, with all rights reserved. Under the copyright laws, neither this manual nor the software may be copied, in whole or in part, without written consent of Apple, except in the normal use of the software or to make a backup copy of the software. The same proprietary and copyright notices must be affixed to any permitted copies as were affixed to the original. This exception does not allow copies to be made for others, whether or not sold, but all of the material purchased (with all backup copies) may be sold, given, or loaned to another person. Under the law, copying includes translating into another language or format.
You may use the software on any computer owned by you, but extra copies cannot be made for this purpose.
© Apple Computer, Inc., 1989 EtherTalk, Finder, Inter Poll,
20525 Mariani Avenue LocalTalk, and TokenTalk are Cupertino, CA 95014 trademarks of Apple Computer, Inc. (408) 996-1010
MacDraw is a registered trademark of Apple, the Apple logo, AppleShare, Claris Corporation.
AppleTalk, Image Writer, LaserWriter,
and Macintosh are registered
trademarks of Apple Computer, Inc.
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Contents
Figures and tables
Preface About This Guide
: Who should read this guide | How to use this guide * If you're new to routers If you're experienced with routers Selecting a network administrator Additional references
PartI Introduction and System Requirements
1 The AppleTalk Internet Router
How the AppleTalk Internet Router works Network connections on your router
What the AppleTalk Internet Router can do Internet routing functions Router control and monitoring functions
Bridges and routers
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2 AppleTalk Terms and Concepts
AppleTalk networks and intemets Network Internet The AppleTalk Network System Network services AppleTalk addressing Packets Nodes Network addresses Node addresses AppleTalk zones Zone names and zone lists An internet zone example Internet routers Hardware-based and software-based routers Seed routers Hops Routing tables
3 System Requirements and Router Environments
System requirements Hardware Software
Macintosh router environments Running the AppleTalk Internet Router on a nondedicated Macintosh computer Running the AppleTalk Internet Router on a dedicated Macintosh computer Running the AppleTalk Internet Router on a Macintosh workstation
Connecting networks to the router ports Ports
4 A quick tour
The Router desk accessory
The Router Setup window
The Network Information window The Port Statistics window
Router operation
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Part II Installing and Using the AppleTalk Internet Router
§ Installing the AppleTalk Internet Router
The AppleTalk Internet Router disk
Installing on a hard disk
Installing the AppleTalk Internet Router with an AppleShare file server Shutting down AppleShare when the router is active
Running the AppleTalk Internet Router without a hard disk
Changes in the Macintosh Control Panel
Effects of installing the router software on a Macintosh
6 Setting Up the AppleTalk Internet Router
Working in the Router Setup window Setting the display Moving the cursor in the Router Setup window Entering text Identifying connected networks Network numbers and ranges Selecting a network range Entering a network number or range Network numbers on nonseed ports Zone names and zone lists Entering zone names in a zone list The port description The User's Port Port status Entering a name for the router Starting the router Router status settings Saving the router setup and restarting Selecting a zone for the router
7 Making Changes in the Router’s Setup
Making changes while the router is active Changing port status Changing router status
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Making changes while the router is inactive
Changing the User's Port Adding or deleting a port Changing port status
Changing the network number or range Changing a network’s zone name or zone list Changing a port description
Changing router status
8 The Network Information Window
Router activity readings — Packets Routed
Recent Activity Rate Network Reliability Recent Network Error Rate
The routing table
Selecting the display style Selecting the numeric display format Selecting the sorting order of the routing table Selecting the sort direction The routing table display Routing information
Network Range
Zone Name
Distance
Forwarding Port
Next Router
9 The Port Statistics Window - Interpreting network statistics Router activity readings Statistical listings
Packets In
Packets Out
Name Requests In Name LookUps Out Data Link Errors Packet Buffer Overflow
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Unknown Network
Hop Count Exceeded
Routing Table Overflow
Local Network Number Conflict
Nonlocal Network Number Conflict
Router version mismatch Resetting the statistics
Router Administration
Reset All Statistics Change Settings Network and node number format Decimal Hexadecimal Network information sorting order Ascending Descending Network information view Summary view Detail view Set password Changing your password Canceling password protection Print Current Window
11 Troubleshooting
Problems with your network system Recognizing network-related problems Common network-related problems Where to find network troubleshooting information Problems with the AppleTalk Internet Router Recognizing router-related problems Errors in router setup Error messages at startup Error messages in the Router desk accessory
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Appendixes
Appendix A Planning an AppleTalk Internet When do you need to create an internet? Planning the physical layout of an internet Creating a map Backbone networks Selecting the backbone network type Where to place a router Selecting a router location on each network Creating redundant routes Adding backbone networks Relative network speed Assigning network numbers, ranges, and zones Assigning network numbers Assigning network ranges Creating AppleTalk zones Creating zones to balance network services in the internet Creating zones to facilitate departmental grouping
Appendix B Effects of the AppleTalk Internet Router on Network Nodes
Connecting a node to a network Reestablishing a node’s AppleTalk connection Selecting a node’s zone
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Figures and tables
PREFACE About This Guide Figure P-1 How to use this guide
CHAPTER 1 The AppleTalk Internet Router
Figure 1-1 Connecting multiple network media on a Macintosh II router Figure 1-2 Bridges and routers on an internet Table 1-1 Possible Macintosh network connections
CHAPTER 2 AppleTalk Terms and Concepts Figure 2-1 Nodes on a network can reside in different zones Figure 2-2 Using seed routers to simplify the router setup procedure Figure 2-3 Hops in an internet route
CHAPTER 4 Aquick tour Figure 4-1 The Router menu Figure 4-2 The Router Setup window Figure 4-3 The Network Information window Figure 4-4 The Port Statistics window
CHAPTER §$ Aquick tour
Figure 5-1 The Installer dialog box Figure 5-2 The shutdown warning dialog box
CHAPTER 6
CHAPTER 8
CHAPTER 9
CHAPTER 10
APPENDIX A
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Figure 5-3 The Macintosh Control Panel after installation of the AppleTalk Internet Router and EtherTalk and TokenTalk drivers
Setting Up the AppleTalk Internet Router
Figure 6-1 The Router Setup window
Figure 6-2 The Zone List dialog box
Figure 6-3 The Setup window's router status settings Table 6-1 Cursor control keys
Table 6-2 Router status settings
The Network Information Window
Figure 8-1 The Network Information window
Figure 8-2 The sort selection pop-up menu, closed and open
Figure 8-3 The Forwarding Port and Next Router in an internet route Table 8-1 Routing table viewing options
The Network Information Window Figure 9-1 The Port Statistics window
Router Administration
Figure 10-1 The Router menu
Figure 10-2 The Settings dialog box
Figure 10-3 The Set Password dialog box
Figure 10-4 The Change Password dialog box Figure 10-5 The Print dialog box for a Laser Writer
Planning an AppleTalk Internet
Figure A-1 How a backbone network is used
Figure A-2 Sample router locations
Figure A-3 A redundant route layout
Figure A-4 Network independence through backbone design
Figure A-5 Laying out the internet for optimum performance
Figure A-6 How some redundant routes can interfere with routing efficiency
Figure A-7 Balancing services through AppleTalk zones |
Figure A-8 How zones help users on different physical networks share services
Table A-1 A sample network numbering system
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P R E F A C E
About This Guide
| HIS GUIDE CONTAINS INSTRUCTIONS FOR INSTALLING AND OPERATING THE AppleTalk® Internet Router.
A router is a device that connects two or more networks, allowing the
network system to grow beyond the size limits of a single network, and improving performance by isolating local traffic on each connected network.
The AppleTalk Internet Router software runs on a Macintosh® computer that can concurrently provide other network services. The Macintosh router can connect up to eight AppleTalk networks.
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Preface: About This Guide
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The AppleTalk Internet Router serves two main functions on an AppleTalk network system:
w It enables a Macintosh computer to perform internet routing, in many cases concurrently with other network services, and provides the familiar Macintosh user interface for router setup and control.
w It provides information to the network administrator about internetwork routes, network activity levels, and error statistics on the network system.
The AppleTalk Internet Router is a component of AppleTalk Phase 2, and may be used only on an internet in which all routers are compatible with AppleTalk Phase 2.
Who should read this guide
This guide was designed for administrators of AppleTalk network systems.
The technical contents of the guide are written for a reader with basic computer experience; the reader is not required to have prior knowledge of network administration. Some of the material is relatively technical, but no new concepts are introduced without explanation.
Macintosh experience is assumed, so concepts such as selecting text or using the mouse are not covered explicitly. If you need assistance with Macintosh concepts not covered here, refer to the owner's guide and the system software guide for your Macintosh computer.
How to use this guide
This manual begins with basic concepts and proceeds to explicit instructions. An experienced network administrator may spend less time on introductory chapters and move quickly to operating instructions; however, it is important for any administrator of the AppleTalk Internet Router to become familiar with AppleTalk concepts and terms, such as zones and internets, as these are central to understanding router services.
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Figure P-1 illustrates the sequence in which users having different levels of experience should read this guide.
es Figure P-1 How to use this guide
If you're experienced with routers
Read Chapter 3 to background materials learn about the in Chapters 1-3 router's environmental ees requirements
Read the internet planning guidelines in Appendix A
Read the description of the router's functions in Chapter 4
Install the router software as described
Follow the router setup instructions in Chapter 6
Refer to Chapters 7-10 as needed for router monitoring and maintenance
Preface: About This Guide
If you’re new to routers
If you’re experienced with
routers
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Preface: About This Guide
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If you haven't previously set up an AppleTalk router, then you will require an introduction to the AppleTalk network system and networking concepts before installing the router:
Carefully study the background materials in Chapters 1 through 3. Read the internet planning guidelines in Appendix A.
Read the description of the router’s functionality in Chapter 4.
Install the router software as described in Chapter 5.
Follow the router setup instructions in Chapter 6.
Refer to Chapters 7 through 10 for router monitoring and maintenance.
If you're already familiar with AppleTalk concepts and terminology and have experience with internets and routers: |
Read Chapter 3 to learn about the router's environmental requirements. Install the router software as described in Chapter 5.
Follow the router setup instructions in Chapter 6.
Refer to Chapters 7 through 10 for router monitoring and maintenance.
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Selecting a network administrator
Installing and administering the AppleTalk Internet Router requires the selection of a network administrator who is responsible for maintaining the network system. If a network administrator has not yet been designated for your network, it's recommended that one be chosen before proceeding.
The responsibilities of the network administrator include some or all of the following tasks:
® participate in planning the physical layout of the network system
= plan the placement of routers, set up routers, and assign network identification numbers
® coordinate the addition, removal, and relocation of devices on the internet, such as computers, printers, and servers
a develop and maintain a current map of the network cabling layout and device locations
= coordinate the selection and implementation of network services, such as file servers and electronic mail facilities
@ perform regular preventive maintenance to help ensure continuous network operation
@ troubleshoot malfunctioning network devices and problems in the cable system
The network administrator must be familiar with Macintosh operation and will benefit from prior training in hardware, software, or data communica- tion. However, for the purposes of administering the AppleTalk Internet Router, the network administrator is not required to have any specific technical background.
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Additional references
The following manuals available from Apple Computer, Inc., provide additional information about using AppleTalk networks:
s The InterePoll Administrator's Guide describes how to use the InterePoll™ network administrator's utility for maintenance and troubleshooting on an AppleTalk network system.
w The LocalTalk Cable System Guide is a brief reference guide to LocalTalk™
cable, hardware, and installation. Use it to help in the initial setup of your _ hetwork and as a basic introduction to LocalTalk networks,
ws The Apple EtherTalk NB User's Guide provides installation and operation guidelines for those using EtherTalk™ in their AppleTalk network system.
a The Apple TokenTalk NB User's Guide provides installation and operation guidelines for those using TokenTalk™ in their AppleTalk network system.
a Inside AppleTalk is the technical reference manual that explicitly describes AppleTalk network protocols.
w The AppleTalk Network System Overview provides an introduction to the AppleTalk network system architecture and AppleTalk protocols.
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Part I
Introduction and system Requirements
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C H A P T E R 1
The AppleTalk Internet Router
( HAT A NETWORK CAN DO FOR INDIVIDUAL COMPUTER USERS, AN INTERNET router can do for network users: It connects computer networks together, allowing users on different networks to communicate with each other, to
share information, and to share network services such as printing and
electronic mail.
The AppleTalk Internet Router software enables a Macintosh® computer to serve as an internet router, through which multiple AppleTalk® networks can be connected, forming an internet. LocalTalk®, EtherTalk™, and TokenTalk™ networks can be interconnected using an AppleTalk Internet
Router.
The AppleTalk Internet Router is an integral component of the AppleTalk network system. It implements the AppleTalk protocols, or rules, that manage the addressing and routing of information to permit internetwork
communication.
Chapter 1: The AppleTalk Internet Router 3
About the Finder...
Key Caps Router
Scrapbook
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How the AppleTalk Internet Router works
The Macintosh computer used as a router directs traffic among connected networks. To do this, the router software acquires and maintains an up-to- date list of all the networks in the internet, as well as the addresses of other routers through which to forward traffic toward its proper destination.
The AppleTalk Internet Router is administered using a Macintosh desk accessory named Router. The network administrator uses this desk accessory to set up the router and to monitor its operation. The Router desk accessory appears in the Apple menu after the router software is installed.
Alarm Clock Depending on the Macintosh computer being used as a router, you can Calculator :
chacser connect from two to eight AppleTalk networks to the router, using a Control Panel combination of the Macintosh serial ports and added internal interface cards. Find File These network connections include LocalTalk™, EtherTalk™, and
TokenTalk™ networks, and any other network types for which Macintosh AppleTalk connections become available in the future.
The Router desk accessory appears in the Apple menu after installation of the router software.
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Network connections on
your router
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Table 1-1 shows configurations of LocalTalk, EtherTalk, and TokenTalk network connections typically available on the Macintosh computers listed.
Other network connections, such as an Ethernet connection for the Macintosh SE, may also be supported, but these are not covered by this document. The AppleTalk Intemet Router will support any network connection developed in conformance with Macintosh AppleTalk connection guidelines.
ws Table 1-1 Possible Macintosh network connections
Connection Macintosh Plus Macintosh SE Macintosh II Macintosh
or SE/30 or Iix lIcx LocalTalk 2 2 2 2 EtherTalk 0° 0° 6 3 TokenTalk 0 0 6 3 Maximum connections 2° 2° 8 5
* EtherTalk interface cards for these Macintosh models may be available from independent vendors, making an additional network connection possible on routers using these computers.
On the following page, Figure 1-1 illustrates how an AppleTalk Internet Router can be used to connect different network types having different cable systems.
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@ Figure 1-1 Connecting multiple network media on a Macintosh II router
Ethernet backbone
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LocalTalk in printer port LocalTalk in modem port EtherTalk interface card
Chapter 1: The AppleTalk Internet Router
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Internet routing functions
Router control and monitoring functions
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What the AppleTalk Internet Router can do
The AppleTalk Internet Router provides two categories of functions:
= internet routing, performed in the “background” (or invisibly to the user) on a Macintosh computer
= router control and monitoring, performed interactively through the Router desk accessory
The AppleTalk Internet Router performs the following functions on an AppleTalk network system:
s increases the potential size and number of devices in the network system by connecting multiple networks together
® connects different AppleTalk network types, such as LocalTalk, EtherTalk, and TokenTalk
® improves internet performance by isolating local traffic within individual networks
® creates zones that conceptually partition the internet, so that users can more efficiently access shared services
A network administrator will use the Router desk accessory for three types of activities:
@ setting up the router a viewing network routing information ® viewing network statistics
Router Setup: The Router Setup window allows you to identify the networks connected to the Macintosh router's ports, and to create internet zones that can be used to group devices on those networks. Up to eight directly connected networks can be defined in the Router Setup window.
Network Information: The router's Network Information window displays general router activity levels as well as the current routing table of the internet, listing networks, zones, and routing information for the entire
internet.
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Port Statistics: The router's Port Stastistics window displays both general routing activity and a port-by-port statistical description of various Operating conditions and errors on the intemet.
Additional functions of the Router desk accessory allow you to set options for viewing routing information, and to print out the various router displays.
Bridges and routers —
The terms bridge and router have often been used interchangeably in networking literature. Both bridges and routers are used to interconnect networks and move information between them, but the differences — between these devices need to be clarified.
~ Note: In some previous documents from Apple, the term bridge has been used generically to refer to bridges and routers. This and future documents from Apple will use the terms bridge and router distinctly.
The difference between bridges and routers can be summarized as follows:
When a bridge is used to join two networks, the result is one expanded network, not an internet. The bridge causes the previously separate networks to appear to any other connected networks as a single network.
A router, however, maintains a logical map of the networks and other routers in an internet, enabling the networks to retain separate identities, and enabling the router to determine the most efficient path through which to transmit data to its destination network.
For readers familiar with the terminology of network protocols, a bridge implements the addressing of nodes on connected networks at the daia-link protocol level, while a router supports addressing at the network protocol level.
Figure 1-2 illustrates the distinction between bridges and routers.
Chapter 1: The AppleTalk Internet Router
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2
AppleTalk Terms and Concepts
B EFORE YOU INSTALL AND USE THE APPLETALK INTERNET ROUTER, YOU should be familiar with some of the fundamental terms and concepts of AppleTalk network systems. The definitions in this chapter will help you to understand the router’s operating principles and the information in its displays.
Network
Internet
The AppleTalk Network
System
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AppleTalk networks and internets
If you have no prior experience with the AppleTalk network system, be sure to study all the concepts in this chapter before proceeding. If you are experienced with AppleTalk, but not familiar with the extended features of AppleTalk Phase 2, read the sections of this chapter titled “AppleTalk Addressing” and “AppleTalk Zones.”
A network is a collection of computers, server devices, and connecting devices that are connected together and capable of communicating with each other through a transmission medium.
Examples of transmission media indude electrical cables, optical fibers, and telephone lines.
For the purposes of this manual, a network is defined as having a unique identity separate from any other network(s) to which it is connected (see “AppleTalk Addressing,” below).
An intemet is any grouping of two or more networks connected by one or more internet routers.
A network system is a communication environment in which network devices and software observe a common set of rules for communicating. These rules are called network protocols, and they explicitly prescribe each step in the process of interaction between network devices.
The AppleTalk network system comprises a set of protocols, each of which governs a different aspect of the communication process, such as how network devices are identified, and how data is formatted for transmission. AppleTalk protcols can be implemented by a wide variety of different devices and transmission media.
While all AppleTalk networks use AppleTalk protocols, they do not all use the same transmission standards, media, or connections.
12 Chapter 2: AppleTalk Terms and Concepts
Network services
AppleTalk addressing
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The AppleTalk network system's design allows you to select the cable systems that best suit the needs of your installation, while retaining the same AppleTalk services and interface throughout the internet Every Macintosh computer is equipped with a built-in LocalTalk network connection, which supports the low-cost, medium-speed LocalTalk cable system.
Altemate network connections include EtherTalk, for the higher performance of the Ethernet network standard, and TokenTalk, for connection to a Token Ring network. These network connections are available through special interface cards in certain Macintosh computers. (See the discussion of network connections at the end of Chapter 3.)
AppleTalk network services are the capabilities that the network system delivers to users, such as printing on network printers, file sharing on network file servers, or communicating through electronic mail.
Transmitting information in an AppleTalk network system—for example, a request from a workstation to open a file on a server—is made possible by an addressing scheme that identifies the sender and destination of the transmission, using network and node addresses. Data is transmitted to and from these addresses in the form of Packets.
Packets
To prepare data for transmission, AppleTalk network software formats the data into packets, adding the addresses of the source and destination devices. A packet is one unit of information that has been formatted for transmission on an AppleTalk network.
AppleTalk packets vary in length from a few characters to a few hundred. A short network transmission might fit into a single packet, while a longer transmission, such as a document file, will usually be broken up into multiple packets.
Some of the packets transmitted on a network are sent not by users, but by network software implementing AppleTalk protocols; for example, the exchange of network information among routers updating each other's ~ routing tables.
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Nodes
Each individually addressable device connected to an AppleTalk network, such as a computer or a LaserWriter® printer, is known as a node.
= A LocalTalk network can support up to 32 nodes.
a An EtherTalk or TokenTalk network can support over 16 million node addresses. The actual maximum number of devices is determined by physical limitations of the network.
Network addresses
An AppleTalk network is identified by either a network number or a network range. These identifiers are defined during the router setup process.
w A LocalTalk network is identified by a single network number that is unique in the intemet.
= All other AppleTalk networks are identified by a network range—a range of contiguous network numbers, such as 1-10. (if EtherTalk is installed on your router, the EtherTalk software must be upgraded to version 2.0 to support network ranges.)
The network number or range must be unique in the intemet: no two networks can have the same number, and no two network ranges can overlap or have any network numbers in common.
Each number in a network range is a network address that can be associated with up to 253 nodes. The size of the network range determines the maximum number of AppleTalk devices on the physical network. For example, a network having the range 1-10 could contain up to 10 x 253, or 2,530 nodes. |
Chapter 6, “Setting Up the AppleTalk Intemet Router,” describes the procedure for entering network numbers and ranges, and Appendix A, “Planning an AppleTalk Internet,” provides additional information about choosing network numbers and network ranges.
Chapter 2: AppleTalk Terms and Concepts :
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AppleTalk zones
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Node addresses
Each individual node on an AppleTalk network is identified by a node address. A node address consists of
ws a network number w anode number, known as the node ID
On a network identified by a network range, the first part of each node's address—the network number portion—is a number within that network range. For example, a network having the range 1-10 would contain nodes with such addresses as 1,96 or 5,77.
An AppleTalk node automatically acquires an address when it is turned on; the address does not need to be assigned by an administrator or user.
Since node addresses are dynamically assigned in this way upon startup, a node may or may not have the same address each time it is turned on. When restarted, a node attempts to reclaim the address it previously used. If, while the node was off, its address was acquired by another, the node will acquire a new address.
A zone in an AppleTalk internet is a means of grouping devices that makes it easier to locate and access network services. AppleTalk zones are conceptual groupings with no physical boundaries; they are defined by the network administrator during the router setup process.
Each node in an AppleTalk internet belongs to one specific zone. Network services delivered by these nodes, such as printing and file service, are presented to users in listings grouped by zone name.
To view or use any service in an AppleTalk internet, a user first selects a zone from a list and then indicates the type of service desired. The user is then presented with a list of all available services of the desired type within the selected zone only, eliminating the need to search through combined listings of all services on the internet at once.
Defining zones can facilitate the departmental grouping of users. Since nodes on different networks can belong to the same zone, and nodes on the same network can belong to different zones, zones let you create and modify work groups without changing any physical connections. An AppleTalk internet can contain any number of zones.
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Zone names and zone lists
During the router setup process, each network connected to the router is identified, and can be associated with one or more zone names.
s A LocalTalk network can be associated with only one zone name. All of the network’s nodes belong to this zone.
a All other AppleTalk networks can be associated with a zone list—a list of one or more zone names available to nodes on that network.
The zone to which an individual node belongs can be chosen from among the zone names associated with that node’s network. This list of zones can be accessed through the Macintosh Control Panel. Unless a node’s zone is explicitly selected from the network's zone list, the node belongs to the default zone for the network, which is defined during router setup.
A node can belong to only one zone, but the node’s user can view and access network services, such as printers and file servers, in all zones.
It’s important to distinguish between the internet zone list —the list of all zones in the internet from which you can access network services—and the network zone list from which you select the zone to which a node will belong. The internet zone list is presented in the Macintosh Chooser desk accessory, while the network zone list is accessed through the Control Panel.
If only one zone is defined for the entire internet, all network services in the internet are presented together in each Macintosh user's Chooser window, and no zone name is displayed.
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An internet zone example
It’s useful to remember that AppleTalk zones are groupings of computers and services defined for organizational purposes, not physical arrangements of devices. Figure 2-1 illustrates this concept: If you connect two networks to a router and enter the same two zones—Zone A and Zone B—in the zone list for each network, either Zone A or Zone B can be selected as the zone in which to register any node,
= Figure 2-1 Nodes on a network can reside in different zones .
File Server in Zone A Zone B
File Server in Zone B Zone A
Network 2
Some key points to remember about zones:
s There is no physical size or shape to a zone; it can include one node, several, or all the nodes on the entire internet.
a It isn’t necessary for nodes that belong to the same zone to be physically contiguous, or on the same network, or even on contiguous networks.
a Any node in a network can belong to any zone whose name appears in that network's zone list.
s A LocalTalk network’s zone list can contain only one zone name.
Chapter 2: AppleTalk Terms and Concepts 17
Hardware-based and software-based routers
Seed routers
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Internet routers
An internet router is used to connect an AppleTalk network to one or more additional AppleTalk networks. The following are general aspects of internet routers for the AppleTalk network system.
A hardware-based router is a dedicated device whose only function is internet routing. It is generally a self-contained device, without a monitor or keyboard, designed to be used only as a router.
A software-based router operates on a general-purpose computer, and may be a dedicated on nondedicated router.
A dedicated router is a computer which, when running internet routing software, can be used for no other purpose. The AppleTalk Internet Router is an example of a nondedicated, software-based router. It operates on a Macintosh computer that may be used concurrently for other network services, eliminating the need to dedicate a computer to either the router or server.
When more than one router is connected to an AppleTalk network, the identifying information for that network, such as its network range and zone list, needs to be entered in only one of the connected routers.
A router in which this identifying information about a network is defined is said to be a seed router for that network. A network must have at least one seed router.
A seed router transmits identifying information about the network to all other routers directly connected to that network. A nonseed router is a router in which information about a network is not entered by the network administrator. Nonseed routers acquire network information from seed routers.
Seed routers make it possible for you to enter setup information for a network only once, no matter how many routers are connected to that network. This capability eliminates the need to enter the same information in several routers, thereby reducing the risk of conflicts due to mistyped network information. .
18 Chapter 2: AppleTalk Terms and Concepts
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Seed router for backbone
Backbone network
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While setting up a router, you need to enter network numbers and zone names for only those networks for which the router is a seed router. An example of this is shown in Figure 2-2.
@ Note: Any router may be both a seed and nonseed router for different connected networks. For example, a router with connections to four networks might serve as a seed router for two of these and as a nonseed router for the remaining two.
Because a router can provide seed routing services to some connected networks and nonseed routing services to others, the router's ports are referred to as seed ports and nonseed ports.
2 Figure 2-2 Using seed routers to simplify the router setup procedure
Nonseed port for backbone
rh.
| Seed port
Chapter 2: AppleTalk Terms and Concepts 19
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A network must have at least one seed router to be recognized by any other internet routers. If two or more routers serve as seed routers for the same network, each must specify the exact same information about the network.
An AppleTalk Internet Router will not recognize any networks connected to nonseed ports until network information is received from the networks’ seed routers. This information is acquired during the regular exchange of routing tables among routers on each network (see “Routing Tables,” following). In
~ the interim, the networks will not appear in the Network Information displays of nonseed routers.
A hop is a unit count between networks on the internet. A hop signifies "one router away.” For example, a network device located on a network separated from your network by three routers would be three hops away.
Hops
AppleTalk protocols allow a maximum of 15 hops in any single transmission path.
= Figure 2-3 Hops in an internet route
+t. Router
mon Router
*t.. Router
Node 1 is 3 hops away from node 2.
20 Chapter 2: AppleTalk Terms and Concepts
Routing tables
Apple Confidential
A routing table is maintained in each AppleTalk Intemet Router. This table lists all networks and routers in the internet, to enable routers to determine the most efficient route for each packet.
The routing table serves the router as a logical map of the internet, specifying the address of the next router in the path to a given destination network, and the distance (in hops) to other networks. The router uses the routing table to determine where (and whether) to forward a data packet.
Each router periodically broadcasts its routing table to other routers on each of its directly connected networks, enabling them to compare and update their own tables with the most recent record of connected networks and routes. In this way, routing tables are kept current as changes are made on the internet.
The routing table maintained by the AppleTalk Internet Router is described in Chapter 8, “The Network Information Window.”
Chapter 2: AppleTalk Terms and Concepts 2]
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j Apple Confidential
C H A P T E R 3
System Requirements and Router Environments
| HIS CHAPTER TELLS YOU WHAT YOU NEED TO KNOW ABOUT ROUTER hardware, software, and environments. Be sure you're familiar with the information in this chapter before you proceed to install or set up the
AppleTalk Internet Router.
23
Hardware
Apple Confidential
System requirements
The following sections specify the hardware and system software required to operate the AppleTalk Intemet Router.
The AppleTalk Internet Router can be operated on any of the following Macintosh computers:
® Macintosh Plus = Macintosh SE family = Macintosh II family
A hard disk is not required on the Macintosh computer running the router software.
The AppleTalk Internet Router cannot be operated on any of the following computers:
® Macintosh XL
® Macintosh 128K
® Macintosh 512K
@ Macintosh 512K enhanced
~ Note: If the AppleTalk Internet Router will be running on a Macintosh concurrently with one other network service, such as file server or print server software, a system with a hard disk and 1 megabyte (MB) of random-access memory (RAM) may be adequate. If more than one additional service is to be provided by the router Macintosh, at least 2 MB of RAM will be required. For details, see “Macintosh Router Environments” later in this chapter.
24 Chapter 3: System Requirements and Router Environments
Software
Apple Confidential
The Macintosh computer running the AppleTalk Intemet Router must be equipped with the following software:
@ System file version 6.0.3 or later.
@ If a TokenTalk network connection is installed on the router, the TokenTalk software must be version 2.0 or later.
= If an EtherTalk network connection is installed on the router, the EtherTalk software must be version 2.0 or later. a
EtherTalk software version 1.2 or earlier can be used temporarily in an AppleTalk Internet Router, to retain connectivity during an internet upgrade from AppleTalk Phase 1 to Phase 2. However, such a network connection will not provide the full functionality of AppleTalk Phase 2, and the network will experience lower performance.
Macintosh router environments
As mentioned previously, one of the advantages of a software-based router is the