Although Ethernet has wide support over all computer platforms, installing and configuring an Ethernet connection for Macintosh computers is not as simple as it is with LocalTalk. Once the hardware has been installed and the software configured, network operations work identically, no matter what network protocol is being used.

• Ethernet vs. LocalTalk

• Ethernet Connections

  Hardware Installation

  Software Installation

  Software Configuration

• Testing Ethernet Jacks
• Ethernet and TCP/IP

• Setting up File Sharing
• LocalTalk

The difference between Ethernet and LocalTalk can be stated simply: LocalTalk is slow and cheap, Ethernet is fast and expensive. The hardware cost of LocalTalk is ~$20, versus Ethernet's cost which can range from $50 to $240. The highest speed LocalTalk can reach is 230 kbs, much slower than Ethernet's 10 Mbps. Neither protocol actually reaches these performance maximums, network traffic and computer overhead greatly reduce the data rate. Nevertheless, Ethernet is noticably faster than LocalTalk.

A more important distinction between the two protocals is the amount of support each has in the world of IBM-compatible computers. Apple's LocalTalk networking standard is not widely accepted by PC users, this has made it is more expensive than ethernet, whose extensive acceptance and varied third-party support has forced prices down. There is better operating system-level support of Ethernet on IBM-compatible computers than LocalTalk, and many more utilities and software applications that can take advantage of the faster standard.

Macintoshes have always had on-board hardware and included system software to support LocalTalk. The MacOS has supported Ethernet since 1987, but built-in Ethernet hardware only made its appearance a few years ago. Most Macintosh computers sold today have "built-in Ethernet" in addition to the LocalTalk standard (low-cost models usually do not have built-in Ethernet). "Built-in" is a somewhat misleading term; while the ethernet hardware is in fact on the motherboard, an external "tranceiver" (much like a teleconnector for LocalTalk) is required to mediate between Ethernet's 10base-T wiring and the Ethernet port. Adding Ethernet to older Macintoshes without "built-in Ethernet" can be prohibitively expensive, particularly for PowerBooks. Newer Macintosh models are including 10base-T ports directly on the motherboard, providing true built in ethernet without the need for a transceiver.

The chart below is a simple guide to the Ethernet Hardware ACS suggests for various Macintosh Models:

Software Installation

Required Ethernet software:

EtherTalk Phase 2

Apple Built-in Ethernet (needed for Macintoshes with built-in Ethernet)

Apple Ethernet LC (needed for some Apple LC cards)

Apple Ethernet NB (needed for some Apple NuBus Cards)

System Configuration

If you have determined that the problem lies with the wall jack, you can test the jack by using the jack with another computer whose built-in Ethernet, Transceiver, wires, and software has all been installed and configured properly (test the setup with a working Ethernet jack). Obviously, it is easiest to do this with a PowerBook 5xx-series Macintosh. Fallaron FriendlyNEt adapters have two LEDs next to the 10base-T jack. The green LED indicates network connectivity, and the orange LED indicates power (the adapter gets its power from the Macintosh). After the PowerBook is plugged into the jack in question, open the Chooser and check for zones (indicating an active wall jack).

If the Ethernet wall jack is active, the problem must lie with the wires, teleconnector, resistor, computer hardware, software, or network configuration. If the jack is inactive, DNO will need to turn on the connection or repair a physical problem. Mail "network@minerva.cis.yale.edu". the person's name, number, room number, etc etc (read the procedures manual), Make sure to include the number on their network jack. The number will be usually L-something. This will help DNO track down the problem faster.

Macintoshes connected to WEB must have Ethernet selected in the MacTCP control panel. EtherTalk is incompatible with Yale's Ethernet network, and random errors will occur if it is used. Many TCP/IP operations will not wrok at all.

One of the functions MacTCP serves is to provide each Macintosh on the network with an IP address. LocalTalked Macintoshes use dynamic addresses, while Ethernetted Macintoshes use static addresses.

Dynamic Addressing:

The first time (after a restart) a LocalTalked computer needs an IP address (for example, when NSCA Telnet is launched), MacTCP asks a server to assign it an address. This address is within a given range; the last number varies randomly, and the third number is assigned by what zone the computer is in. The Macintosh will retain the IP address until it is shutdown.

Static Addressing:

Ethernetted Macintoshes keep their IP address over restart. All Ethernet hardware (whether it is built-in, on a card, or attatched to the serial port) contains a "hardware address" that MacTCP can use to identify the Macintosh to a server. The server maintains a "bootP" table that keeps a record of what IP address is assigned to each hardware address. The first time an Ethernetted Macintosh requires an IP address (for example, when NCSA Telnet is launched), MacTCP looks up the Macintosh's hardware address in the bootP table and gets the static IP address assigned to it.

Because of the way static addressing works, it is impossible for an Ethernetted Macintosh to use static addressing until its hardware address is entered into the bootP table. For Apple-built Ethernet cards (or for Macintoshes with built-in Ethernet), launch the Apple LAN Utility to display the Ethernet hardware address: This address needs to be given to DNO to be entered into the bootP table. Ethernet connections will not be turned on until DNO has the hardware address. For non-apple Ethernet hardware, the hardware address should be written somewhere on the hardware itself. If it is not, the hardware should be brought into the CHuNC where the Network CAs can use a live Ethernet connection to determine the address (by option-clicking on MacTCP's "Ethernet" icon).