Quote:
Originally Posted by
Xenomos 
Could someone help me with a couple basic questions? I was considering buying this AirPort for my new Mac Pro and MBP and I don't know anything about 802.11n or Gigabit Ethernet, except that one's in my Macs and not in the new Airport...and that's apparently not good.
1) Is GbE a wireless or wired connection...thingie?
2) With DSL at 3 Mbps, is my speed going to be adversly affected or not up to it's full potential without GbE?
Thanks in advance, I know this is terribly basic but I know nothing about the subject and after hearing everyone complain about this new product, it makes me hesitate in purchasing one (though I do need a router regardless).
"Ethernet" is the near-universal
wired form of computer network connection. The various generations of Ethernet speed visible in the market today are 10 Mbps, 100 Mbps, and 1,000 Mbps (a.k.a. 1Gbps Ethernet or GbE).
Some folks (myself included) have a mix of wired and wireless devices in our homes, with the wired devices connect (by Ethernet) into our wi-fi basestation. The new Airport model includes 3 Ethernet ports (for local LAN usage), vs. only 1 port on the former Airport Extreme. The issue being bandied about is when, and how much, it matters that the speed of those Ethernet ports is limited to 100 Mbps. If you're not using them (and use only wireless connections), it matters not at all.
If all one had in their home network were a single machine, connected over wi-fi to their DSL modem, which connects in turn (at, say, 3Mbps) out to the Internet, then the lower DSL speed would be the bottleneck, even with the oldest & slowest form of wi-fi, 802.11b (with a theoretical max of 11Mbps and 4-6 Mbps typical). If, instead, that single machine were connected over Ethernet to the wi-fi basestation and on to the DSL modem and the public Internet, the DSL speed would still be the bottleneck, even if that Ethernet were the oldest/slowest, running at just 10 Mbps.
But the more interesting scenario is where one has a non-trivial home network ... and those machines talk to
each other, within the home, as well as out to the public Internet.
In a combo home network using both wi-fi and Ethernet links, the second-generation wi-fi, 802.11g (with a theoretical max of 54 Mbps and 20-30 Mbps typical) can help those
within-home connections. Here, having one (or more) 100 Mbps Ethernet ports on the wi-fi base station (the Airport) means that the Ethernet part would
not be the bottleneck -- it would either be the wi-fi link (when using that), or (most often) that 3Mbps DSL connection to the outside world (which starts to seem puny, by comparison).
Now we have 802.11n wi-fi (pre-standards version). It is supposed to provide 200 Mbps typical, with a theoretical max of 540 Mbps -- and thus 10x the theoretical max of 802.11g, which in turn was 5x the theoretical max of 802.11b. Not only that, but 802.11n provides a bigger range between the base and the nodes communicating with it (maybe 1.5x or 2x that of 802.11g). This is all summarized pretty well on the
802.11 Wikipedia page.
Using those numbers for the capacity of 802.11n connections, yes, they will go somewhat faster than a (wired) 100 Mbps Ethernet connection ... so the Ethernet link to the Airport base station becomes the limiting factor in the household LAN, while that 3 Mbps DSL connection to the public Internet is now way way way smaller than all the interconnections, wired or wireless, within your home, and thus
it (the DSL connection) is the undisputed bottleneck for communications with the public Internet.
Another factor that blurs this comparison, though, is that the wi-fi speeds are likely to be slower in a mixed "n" wi-fi network, where some nodes are using one of the older wi-fi generations (b or g). In the early days of 802.11g, the presence of a "b" node would slow all the
other wi-fi activity, even between two "g" nodes, but that was later refined so that the "g" nodes could talk to each other at full speed, and only the links to the slower "b" nodes would (necessarily) operate at the slower "b" rates. Now that we're moving up to "n", there's been some mention (even on Apple's own product description page) that mixed node types results in some kind of slowing, but I have yet to see any statement precise enough to distinguish whether a "b" or "g" node slows down
all the traffic or just that on the links to those slower nodes. So, just maybe, the presence of older wi-fi nodes in one's shiny new 802.11n wi-fi network will slow all the wi-fi traffic down enough to go slower than a 100 Mbps Ethernet connection.
I've also seen some posters here on AI seeming to claim that the 802.11n max speed will be
less than the 100 Mbps Ethernet links, but I don't understand those claims, as they flat out contradict what the Wikipedia article says (and what I've heard in various other venues) about the typical speeds provided by 802.11n. Maybe they are taking it as a given that wi-fi networks (at least for the early years) will have older ("g" or even "b") nodes in them, and that the presence of those older nodes will necessarily slow the whole network to less than 100 Mbps.
So, bottom line, yes, it looks like the 100 Mbps Ethernet in the new Airport base stations will be somewhat slower than the speed of the 802.11n links that it provides. And it is mildly puzzling that the new Airport does not provide 10/100/1000 Ethernet ports that would operate at the full 1 Gbps (1,000 Mbps), since that has indeed become so common in other devices -- including all of Apple's computers. But, personally, I don't see that it's such a big deal.
The one scenario that I can see where the lack of GbE on the Airport would ever matter is if you had multiple hard-wired devices that all had GbE and were using the Airport as their hub -- and so would be limited to 100 Mbps rather than being able to use their full GbE in talking with each other. If that matters, get a separate GbE hub and use
that to interconnect all those screaming-fast computers to each other, with just a single link to the Airport. For connections from them, through the Ethernet to the Airport and on out to the public Internet, that 3 Mbps DSL link is
still going to be, by far, the greatest limitation. Only when going between a wired device with GbE and an 802.11n device will the Airport's 100 Mbps Ethernet speed-limit matter ... and then only by a factor of 2 or so.
\
