Description: Apple II Workstation Card: Workstations and Zones (2/97)
Header: Apple II Workstation Card: Workstations and Zones (2/97)

 Apple II Workstation Card: Workstations and Zones (2/97)

 Article Created: 25 May 1989
 Article Reviewed/Updated: 12 February 1997

 TOPIC -----------------------------------------------------------

 This article discusses the ways in which the Apple II Workstation Card
 understands zones and network IDs. Some of the discussion refers to the
 following setup diagram:

 DISCUSSION ------------------------------------------------------


 Setup:

    Ethernet                           LocalTalk

 --------|-------------- FastPath---------|----------|---------------|
        |                                |          |               |
    Macintosh II server              diskless       LaserWriter     |
    w/Apple II start                  Apple II                  Macintosh SE
    blocks
    zone: zone1                            zone: zone1
   net #: 1                               net #:   2
 -----------------------------------------------------------------------

 The only zone-related limitation concerns starting an Apple II diskless
 workstation. The ProDOS-prepared AppleShare server must be within the same
 zone as the diskless workstation. Once the Apple II has started over the
 network, the Workstation Card and the Apple IIGS are fully aware of zones and
 network IDs.  This means that, once started, the Apple II can log on any
 ProDOS-prepared, AppleShare file server in any zone available on the
 Internet. The number of bridges or zones does not affect the access to
 another server.

 When the Apple II broadcasts an AppleTalk Transaction Protocol (ATP) request,
 this ATP request is sent across the entire zone in search of a file server
 with boot blocks. In the given example, both 'net#1' and 'net#2' are in the
 same zone, "zone1". The FastPath passes zone broadcasts from either "net#1"
 or "net#2" to the other.

 Once startup is completed, the AppleShare II Workstation software is
 executed. From this application, the user can choose the appropriate zone and
 log on to the desired ProDOS-prepared server. At this time, Name Binding
 Protocol (NBP) translates the names into the associated Internet socket
 addresses of the corresponding network entities. In this case, the Apple II
 workstation name is translated to an address, and the server name is
 translated to an address.  These addresses notate network IDs, zone IDs,
 bridge IDs, and network entity IDs.

 When a workstation is instructed to print, it looks for the chosen printer
 with the address provided by NBP. The address specifies the location of the
 printer. Because the printer is on "net#2" (the same network as the Macintosh
 SE), the FastPath determines that the address belongs on "net#2". The
 FastPath does not accept the traffic, because the address is local to
 "net#2". However, when the Apple II requests service from the server, the
 FastPath recognizes the address as one that belongs to "net#1". In this
 condition, the FastPath lets the request travel over the bridge to the server.

 Typically, routing is handled at the fourth OSI layer, the transport layer of
 AppleTalk. Manufacturers working with AppleTalk use the transport layer to
 handle routing. Manufacturers working with other protocols may handle routing
 at a higher layer in the OSI model.


 Article Change History:
 12 Feb 1997 - Reviewed for technical accuracy, revised formatting.
 Copyright 1989-97,  Apple Computer, Inc.
 Keywords: