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AppleTalk and Network Traffic

Hello all,

I'm looking for an official article or study that shows that the "chattiness" of AppleTalk found in 10.3 and later is a myth. My boss wants to turn off AppleTalk on all the Macs in the office because he thinks it causes an increase in network traffic. All the Macs use AppleTalk to print to HP and Canon printers, because IP printing is flaky. A Google search only turns up mailing list discussions and forum posts that say it's just as chatty as the other protocols out there. I'd rather not turn off AppleTalk since it eliminates printing problems for us. Thanks.

MacBook Pro (2.4 GHz C2D) | Mac mini (1.42 GHz PPC) | Mac OS X (10.5.2)

Posted on Jul 17, 2008 10:07 AM

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3 replies

Jul 18, 2008 9:16 AM in response to MJedi

<sigh>Not again. Hasn't this one managed to die yet?

The myth was founded by lazy network admins back in the days when 10Base-T was the standard, 10Base-2 was just starting to take root and most people ran AppleTalk over daisy-chained 230k serial cables.

On large networks (> 100 systems or so) AARP (the element of AppleTalk that is responsible for most of the 'chattiness') could consume a pair percentage of the available 230kbps on the original serial cabling.

Even that traffic could be mitigated by implementing an AppleTalk router, and was further reduced in AppleTalk Phase 2, introduced in System 7 around 1996. That's 12 years ago.

In addition, due to the serial nature of AppleTalk, traffic from a system at one end of the network had to pass through every other node to get to a machine at the other end. This reduced overall throughput.

Modern networks have increased their bandwidth significantly. Even a 100Base-T network has 400 times the available bandwidth of the original serial implementation. Gigabit ethernet has 4,000 times the bandwidth. In addition, these networks are switched, which means that any conversation between two nodes is only sent down the wires leading to those specific nodes (and any intermediate switches).

So, the minimal number of AppleTalk packets on the wire (remember, much of the chattiness went away in 1996), coupled with the switched nature of modern networks that are vastly faster than the old serial cables means that a typical AppleTalk network consumes a trivial amount of bandwidth. Really.

In terms of how to educate people nowadays, there are three things to point out:

1) AARP (and AppleTalk in general) is LESS 'chatty' than TCP/IP
2) AARP (and AppleTalk in general) is LESS 'chatty' than TCP/IP
3) AARP (and AppleTalk in general) is LESS 'chatty' than TCP/IP

(yes, you have to make the point three times)

If he wants further proof, run a tcpdump from any node on the network and count the number of AppleTalk packets seen.
Then compare that with the number of ARP (Ethernet Address Resolution Protocol) packets.
Then compare that with the number of NETBIOS packets.

If your network is so strained that the few AppleTalk packets are breaking it I suggest turning off all those Windows machines since NETBIOS generates far more traffic than AppleTalk does.

Jul 21, 2008 8:20 PM in response to Camelot

No way AppleTalk is less chatty than TCP/IP on a properly tuned network. AppleTalk or rather its upper layer services are broadcast intensive, so switching does you no good whatsoever. Routers help, but only if common services share the same "wire" otherwise your still forwarding service discovery. It's probably not as bad today since the Chooser has gone away, but it's still a broadcast heavy protocol (or at least its services are) that doesn't scale well, and when implemented on networks designed for TCP/IP, gets noticed. If it's just a few devices like in this case printers, it shouldn't be a problem, but to universally say AppleTalk is not chatty is not accurate. Sure it's not as bad as IPX or poorly implemented NetBIOS, but it's still enough that too many devices with it enabled can generate far too many broadcasts.

Jul 23, 2008 12:35 AM in response to LittleSaint

No way AppleTalk is less chatty than TCP/IP on a properly tuned network


Try it some time. For the typical network with a mix of platforms, the chattiness of AppleTalk is certainly no worse that other protocols, and often significantly better.
I am, for sure, excluding pre-Mac OS X systems because, yes, the Chooser would blast a series of broadcasts out across the network, but I regard that as one of those other legacy elements whose memory far outlives the reality.
In any case, especially in the modern network we're still talking fractions of a percent of the available bandwidth.

Back to the OP, though - few services require AppleTalk, itself. Bonjour has replaced much of AppleTalk's auto-discovery protocols (the source of much of the (supposed) problem). You can have a perfectly function Mac network without using AppleTalk. My point was intended to indicate that even if you do have it turned on, it's not the problem it was once perceived to be.

AppleTalk and Network Traffic

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