This article originally appeared in TidBITS on 1998-09-14 at 12:00 p.m.
The permanent URL for this article is:
Include images: Off

Creating a Simple Ethernet Network

by Adam C. Engst

Recently in TidBITS, I've been writing about connecting peripherals to the iMac, since it lacks serial, ADB, and SCSI ports. What the iMac does have, though, is built-in 10/100Base-T Ethernet, which is useful for connecting to Macs and Ethernet-capable printers. All this has prompted questions about setting up a small Ethernet network at home. I did this with relatively little fuss or expense, and you can as well.

First, though, why would you choose Ethernet over LocalTalk, which uses PhoneNet connectors and standard telephone wire? Aside from needing to connect Ethernet-only devices, the simple answer is raw speed. LocalTalk runs at a theoretical maximum of 230.4 Kbps, whereas standard Ethernet can theoretically hit 10 Mbps and, with the appropriate hardware, 100 Mbps. In reality, Ethernet seldom achieves that speed on a Mac, but it's much faster than LocalTalk.

What are an Ethernet network's main uses? Fast file sharing, via the Mac OS's Personal File Sharing, is the big one, and printing large files can work much faster over Ethernet. Other uses are less obvious: controlling other Macs via Netopia's Timbuktu Pro, sharing a networked calendar and contact database via Now Up-to-Date/Now Contact (soon to be Eudora Planner), or connecting multiple Macs to a single Internet connection.


This final possibility - connecting several Macs to one Internet connection - bears additional discussion. With the increasing availability and popularity of high-speed cable modems and ADSL Internet connections, Mac users often want to share Internet access with multiple Macs. This requires two parts: an Ethernet or LocalTalk network and special gateway software. I know of three Mac-based possibilities right now, Vicomsoft's Internet Gateway, Vicomsoft's two-user SurfDoubler, and Sustainable Softworks' IPNetRouter. I haven't used these products, but the basic idea is that you run them on the Mac with the Internet connection, and they then convince other Macs (or PCs) on the network that the Internet connection is available.


Ethernet Cabling -- Now that we've established what you might want to do with an Ethernet network, let's get down to the details. The first decision you must make is the sort of cabling you want to install. There are essentially two choices, although many networking people might disagree. Let me explain. There three basic types of Ethernet cables: 10Base-T (sometimes referred to as twisted pair), 10Base-2 (also known as thin Ethernet), and 10Base-5 (also called thick Ethernet). 10Base-2 and 10Base-5 use coaxial cable, and 10Base-2 uses a round BNC connector that looks like connectors used for cable television and TV antennas. 10Base-T uses cabling that looks a bit like standard telephone cabling but has an RJ-45 connector that's larger than telephone RJ-11 connectors.

10Base-T is the unchallenged standard in Ethernet networking, and many would argue that you should never use anything but 10Base-T. I haven't heard of anyone using 10Base-5 recently, and it's difficult to find hardware that supports it. 10Base-2 is the odd one, and I mention it because it can be easier and cheaper to use for small, static networks than 10Base-T. Here's why:

10Base-T typically uses a star configuration for the network, with a hub at the center of the star. A cable leads from the hub to each computer on the network, or to another hub, thus linking multiple stars. Hubs are relatively inexpensive these days - in the $50 range. However, at our house we have four widely separated sets of computers - my office, Tonya's office, our server room, and the kitchen - so we'd need four hubs. When we installed our wiring, buying multiple hubs seemed excessive, so we went with 10Base-2, which you can daisy-chain like LocalTalk. Each end of a 10Base-2 network must be terminated with a 50-ohm resistor, but otherwise you can keep adding devices to the chain wherever you want.

The advantage of 10Base-T is its flexibility and robustness. If a cable breaks, only a single machine drops off the network. Plus, it's easy to add or remove new devices quickly, which is helpful in a dynamic office situation. In comparison, if something happens to a cable in a 10Base-2 network, the entire network fails. Adding a new device also interrupts network traffic until you restore the chain. However, since our computers seldom move, and since our cabling is well-installed, 10Base-2 made more sense at the time and saved us a few hundred dollars.

In general, I recommend 10Base-T, since it's easier to find devices that work with it. However, if you have a specific situation like ours and you have a friend who knows about networking, a 10Base-2 network may cost less. The two aren't mutually exclusive, and we have a hub in the kitchen because our recently burgled PowerBook 5300 and its PowerBook G3 replacement support only 10Base-T. The hub has a single 10Base-2 port, so it's just another device on the 10Base-2 cable, and from the hub, we can attach up to eight 10Base-T devices.

Ethernet Hardware -- It's important to decide on your Ethernet cabling, because that affects the choice of hardware you buy to connect your Macs (or PCs - Ethernet is platform-agnostic) to the network. Be careful to make sure to match any hardware with the cabling you've chosen. Although a variety of manufacturers sell Ethernet hardware, you're unlikely to go wrong with the main Mac networking companies, such as Asante, Dayna, Farallon, and Sonic Systems. In most cases with Ethernet hardware, you can shop purely on price.


< pktscsi.html>

Making the Connection -- Once you install your hardware and hook up the cables (hubs and Ethernet cards often come with booklets explaining the basics of networking), you're ready to configure software.

The Mac OS includes all the software you need. First, open the AppleTalk control panel (or the Network control panel if you aren't using Open Transport) and set it to use Ethernet rather than the printer port. If you plan to hook your network to the Internet, you also must tell the TCP/IP control panel to use Ethernet - the rest of the settings depend on your specific situation. If you plan to share files, turn on file sharing in the File Sharing control panel (Sharing Setup before Mac OS 8).

I've found that the easiest way to share files on a personal network where you own all the Macs is to log in as the owner. To do this, use a single Owner Name and no password when filling in the Network Identity settings for all your Macs. Then, when you connect to a remote machine using the Chooser, you won't have to type a new name or password. Better yet, it doesn't matter if you've shared any volumes or folders by selecting them and choosing Sharing from the File menu. If you want to restrict access, first configure user names and passwords in the Users & Groups control panel, and then set up access privileges for individual items in their Sharing windows.

After file sharing is active, or if you've connected a printer to your network, in the Chooser click either AppleShare or LaserWriter 8, as appropriate. The remote Mac or printer should appear in the right-hand pane, and double-clicking it will select it for mounting or setup. If nothing shows up in the Chooser, check that the remote Mac is set to use Ethernet and has file sharing active, that any printers are on, and that the cables are plugged in securely.

Adding a PC to a network is easy on the hardware side of things, since you just install a card and plug in cables. Software is more difficult. Windows should detect card's presence and install the drivers or prompt you for a disk containing them. Then you must enter the correct settings in the Network control panel. It's beyond the scope of this article to explain how to do that, but concentrate on TCP/IP components, since TCP/IP is a protocol common to Macs and PCs. With it properly configured, you could run a Macintosh FTP server, for instance, and connect to it using a Windows FTP client. Other products you may find useful for sharing files and printers between Macs and PCs include DAVE 2.0 from Thursby Software Systems, PC MACLAN from Miramar Systems, COPSTalk 2.1 from COPS, and Timbuktu Pro 32 from Netopia.

< ct2info.html>
< 32over.html>

Most of the time, networks, particularly simple ones, work right away, though, so it's likely that you'll be up and running within minutes of plugging in the cables and configuring the proper control panels.