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ATPM 6.10
October 2000


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How To Become a Network Guru in 10 Easy Steps

by Matthew Glidden,

Part 10—Factors in Macintosh Network Speed

If there’s one thing everyone can agree on in this election year, it’s fast networks. Republican, Democrat, or Independent, we all like our networks to run as fast as possible. (Non-American readers please bear with me; I’ll have the relevant material shortly.) Fast networks don’t just happen by themselves, though. As easily as Macintosh networks come together, getting maximum performance can take some work.

The saying “a chain is only as strong as its weakest link” definitely applies to a network, as your network performance will generally be only as fast as the slowest components. It’s critical, therefore, to know which components affect performance and how to get them working their best.

Disclaimer: Since there are so many permutations of computers, wiring, and functions, it isn’t practical for me to discuss speed absolutes, like “Your network should be such-and-such fast” or “This will improve performance by so-and-so.” Each component can help and hinder the network and you’ll discover how much when you make the changes. I do try to estimate which changes will, generally speaking, have the greatest impact.

Factor One: Network Adapter

A network adapter is a device that physically connects your Mac to your network, converting the network signals into data for the CPU and vice versa. There are two popular types of Mac networking, LocalTalk (which uses the Modem or Printer serial port) and twisted-pair Ethernet (which uses a dedicated port) and comes in three speeds: 10 Mb, 100 Mb (fast), and 1000 Mb (gigabit). All Power Macs, iMacs, and G3/G4s include built-in Ethernet of varying speeds. Other Mac models can add an Ethernet adapter (see ATPM 5.09 for details).

LocalTalk connections have one speed, 230 kilobits per second (about 28 kilobytes), since they use Mac serial ports.

Ethernet’s three speeds can be deceptive, since they imply you can increase your network speed tenfold just by purchasing a faster network adapter. Sadly, this is not the case. To start with, a 10 Mb Ethernet adapter won’t reach full speed—about 1.25 megabytes per second—outside of a development laboratory where the components are all specially optimized. “Real world” performance will be more like 100-200 kilobytes per second in an average Mac network. 100 Mb Ethernet will be 4-6 times faster (not 10), and 1000 Mb a few times faster still, but still not the blinding speed you might imagine.

Conclusion: All that said, switching to a faster adapter is usually the simplest way to improve network speed, assuming you also get a faster hub. Speaking of which…

Factor Two: Network Hub (or Switch)

Most Ethernet networks use a hub or switch as the central connection point. The hub manages the network traffic, moving the data where it needs to go. Hubs, like the network adapters, have three speed ratings, 10 Mb, 100 Mb, and 1000 Mb. You need a hub that supports the given speed rating to use it on your network.

People often ask me whether to purchase a hub or switch for their network, since hubs are cheaper but switches usually advertise themselves as more efficient. For home or small office use, I usually recommend that people save the money and stick with a hub, since the network traffic will be relatively light compared to a business network (where I suggest switches). If you move a bunch of data around the network, you may notice a speed difference between a 100 Mb hub and a 100 Mb switch, but you also may not.

Conclusion: Your hub must support your highest network speed to make use of it, but otherwise the model and make should make relatively little difference in speed.

Factor Three: Network Adapter Software

When you install a network adapter or use the one that came with your Mac, you use specialized software (usually one or two extensions) to handle the translation of network data. For Macs with built-in Ethernet, the software comes pre-installed, but third-party network adapters usually come with software disk or CD-ROM. The newer the software is, generally speaking, the better the network adapter’s performance will be. Network software updates usually fix bugs and improve translation, so check the adapter’s Web site regularly for updates (this includes Apple, which updates its Ethernet software from time to time).

Conclusion: The effects of software vary widely. Speed increases come from quashed bugs that hindered network adapter performance or improvements to the network translation programs.

Factor Four: Motherboard Speed

Like your skeleton, a Mac’s motherboard defines what it’s capable of. However you expand or modify your Mac, the motherboard’s speed has inherent limits that include (to a degree) network performance. If you overclock your Mac’s CPU, for example, the computer may respond more quickly, but you can reach a point where components (like the network adapter) can’t handle the speed increase, and fail.

Conclusion: A faster motherboard generally means faster components all around, including network performance. Upgrading the motherboard, however, means getting a new Mac.

Factor Five: Hark Disk Throughput

Disk performance, measured by how much information you can read or write from the disk in a second, is often the primary bottleneck to computer (and network) performance. Since files are typically the only data you want to send across the network, your hard disk has to read each file to complete the network transaction. Maximize your disk performance (on all relevant Macs) and your network performance should see a marked improvement.

You can improve your disk performance by using a faster disk, which makes more information available, and a more efficient disk interface, which gives more information to the CPU at once. Generally, newer hard drives are faster, up to 10K RPM and more. Interfaces—including SCSI, IDE, and FibreChannel—have become more efficient with time and usually take the form of an expansion card. Get a high-speed disk interface with a high-speed drive and you’re almost certain to notice the change on your network (and everywhere else).

Conclusion: Upgrading your disk drive and interface will almost certainly increase network performance, although the performance increase depends on what you used previously.

Factor Six: Network Server

Most home or small offices use the built-in, peer-to-peer, Mac networking since it’s easy to use and comes pre-installed. If you can justify the expense, however, purchasing actual network server software (Apple’s AppleShare IP) will lift your performance significantly. The downside? AppleShare IP 6.3 runs you $999 from the Apple Store (and you’ll need a computer to run it on, of course).

Conclusion: AppleShare IP improves network performance significantly but also leaves your wallet considerably lighter.

Factor Seven: AppleTalk vs. TCP/IP

In network circles, a lot has been said (trust me, a lot) about AppleTalk relative to other network protocols, since AppleTalk is somewhat less efficient (and therefore slower) than protocols like TCP/IP. For home and small office users, though, AppleTalk makes up for the speed in convenience. Although it’s possible to see a performance increase using plain TCP/IP on your network (see ATPM 6.07 for details), you lose the Finder’s easy drag-and-drop functionality.

Conclusion: AppleTalk is (somewhat) slower than other options, but makes up for it in convenience.

Factor Eight: Sharing an Internet Connection

The performance of your network is limited somewhat by outside factors, such as your Internet connection. If you have a cable or DSL modem, for example, you have little control over how quickly Internet data comes and goes (your cable or DSL company sets that limit, either by availability or choice). The typical limit on an Internet connection is around 200 kilobytes per second, which is easily within the range of a 10 Mb network adapter.

Conclusion: Sharing an Internet connection has its own speed limitations that are out of the home network user’s control.

Also in This Series

Reader Comments (3)

Babu Joseph · July 19, 2001 - 06:37 EST #1
Can you tell me the speed ratio between a 100mbps switch and 100mbps hub?
Matthew Glidden (ATPM Staff) · July 19, 2001 - 23:36 EST #2
The speed difference will depend on what kind of setup you use the hub and switch in. If you're using a home network, where network use is fairly sporadic, you probably won't notice a great difference between the two, as the traffic won't be heavy enough for the switch's ability to balance the total available bandwidth among the ports in use. In larger networks that see constant traffic, the switch will perform better, but how much better depends on how much traffic is moving, what kind of traffic, etc. There are so many factors, it's almost impossible to nail down exact performance numbers. If you're looking for a device that will be in fairly constant use (which is rare in a home network), you should go with a switch. Otherwise, you can decide if the chance for better performance is worth the extra cost (which isn't as big as it used to be, fortunately).
Leo · February 9, 2002 - 17:10 EST #3
Very good column. Precise and to the point.

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