MkLinux Test Network

This document describes the network that my MkLinux machine is part of.

Network Entities:

• Power Macintosh 7100/66 (name: boa), can run either MacOS or MkLinux
• Macintosh LC 475 (name: sphinx)
• HP LaserJet 4MP
• HP DeskWriter 540c

This network is isolated from other networks, except that the LC 475 runs Apple Remote Access and can communicate via modem with my main work Macintosh (muriqui) over an ARA connection. When so connected, the LC becomes part of the primate.wisc.edu domain on the Internet, and part of the Primate Center zone on the UW-Madison campus AppleTalk network.

All devices listed above have LocalTalk interfaces and thus can communicate using AppleTalk over LocalTalk wiring. I wanted to maintain this connectivity whether boa was running MacOS or MkLinux; however, MkLinux has ethernet support only. To that end it became necessary to put the devices on ethernet, or at least to make them appear as though they were ethernetted. I did this as follows:

• An Asante 8-port twisted-pair ethernet hub serves as the center of the network.
• The Power Macintosh 7100 (boa) has a built-in ethernet interface (actually, one of those non-standard AAUI things that requires a "FriendlyNet" transceiver to connect to TP cabling).
• The LC 475 (sphinx) goes on ethernet easily using an internal Asante card.
• The HP LaserJet 4MP and HP DeskWriter 540c have no ethernet interface. They're bridged onto the ethernet using an Asante Micro AsantePrint LocalTalk-to-ethernet hardware bridge.

During the course of converting from a LocalTalk network to an ethernet, I originally tried using a Sonic Systems microPrint LocalTalk-to-ethernet hardware bridge and LaserWriter Bridge. This worked sort-of okay, although I ran into the following problems before switching to the Asante bridge listed above:

• The Sonic device bridges only a single LocalTalk device onto ethernet. (I believe newer Sonic devices are capable of 2 or 8 devices.)
• When the LC 475 has an ARA connection open, the device bridged by the microPrint becomes invisible in the LC's Chooser (this happened for both the LaserJet 4MP and the DeskWriter 540c). In other words, with ARA active the bridge didn't work, thus rendering it effectively useless to the LC. This problem doesn't happen if the LC and the LaserJet or DeskWriter are connected directly over LocalTalk, or (for the LaserJet) using LaserWriter bridge. Since it also doesn't happen with the Asante bridge, I assume the problem is with the Sonic bridge itself.
• With LaserWriter bridge, it is necessary to unplug the Power Macintosh from the LocalTalk network even if its ethernet interface is selected. If it remains connected to the LocalTalk network, LaserWriter Bridge (running on the LC 475) doesn't work. Apparently the Power Macintosh isn't completely ignoring its LocalTalk interface even when ethernet is selected and some sort of loop is created.
• LaserWriter Bridge is not compatible with Open Transport, so the machine on which it runs must run Classic AppleTalk. Nor will it bridge anything but laser printers; it won't bridge a DeskWriter or a Macintosh.

Change History

13 July 1996

• Switched from Sonic Systems microPrint to Asante Micro AsantePrint LocalTalk-to-ethernet hardware bridge, which made things simpler.