[kupan787]

I posted a thread about this a few months back, but can't find it when searching. And it never got any responses, so I try again....

Ok, so I have an 802.11g network (all Apple Airport products on the network, all running at 802.11g). If I do an FTP transfer from PowerMac to Powerbook via the Airport Extreme router, I see speeds of 1.3-1.5MBps (about 11.7Mbps). Now, I understand that I wont ever get the fully rated 54Mbps, but I have heard that you should be able to reliably get 25-30Mbps in most situations with good signal (which both computers report full bars). We are not even close.

Now, I just tried doing a computer to computer network (so no router involved), with both computers only 5 feet apart. Again, FTP from PowerMac to Powerbook, and saw speeds of 2MBps (or roughly 16.7Mbps). A tiny bit better, but still not what I was hoping for.

Now why is this an issue you may ask? Well, we have comcast, and I routinely can get 1-1.2 MBps downloads (so in the area of 10Mbps). And supposedly, they have this new "Powerburst" thing, that should boost my download to 24Mbps for the first 20MB of a file. So my "regular" internet uses up [virtually] all the bandwidth my wireless can handle, and if I get a "powerboost" I can't even get the full effect.

Any thoughts on why my wireless would suck so bad? I would think with a computer to computer network, I would see close to optimal speeds (so like 25-30Mbps).

[ghporter]

What's your speed, computer to computer, WIRED? That will say an awful lot about what your next step should be.

[kupan787]

Originally Posted by ghporter 

What's your speed, computer to computer, WIRED? That will say an awful lot about what your next step should be.

Sorry for the delay in response. Computer to computer wired:

Gigabit to gigabit using Cat5e: I get 6 MBps. That translates to roughly 50Mbps, which is half duplex 100baseT (correct?)

Gigabit to 100baseT: 3.5MBps, which is roughly 28Mbps.

So I know the computer is able to transfer at up to at least 50Mbps. I would bet with better cabling, and a switch (as opposed to a direct computer to computer wire) things might be even a little better.

On an odd note, my wireless network has slowed down even more. Tonight, in a strictly 802.11g test (set my Airport to 802.11g only mode), I am only getting speeds of 650KBps. Could it be that there are 10 other wireless APs in my area that is some how causing interference and slow down? I am getting full bars on both machines. Frustrating...

[ghporter]

I would expect much higher speeds with a gig-to-gig connection, and no, I don't think that Cat 5e is the culprit; it's rated high enough that you should get really good speeds with it, up to and including 1000Mbps. You're correct that you're seeing roughly half of what 100BaseT should give you, but you also shouldn't encounter half-duplex unless you've set it up. You're also getting roughly 1/4 to 1/3 the speeds you might expect from a 100BaseT connection with your gig-to-100BaseT test. Realistically, there is quite a bit of overhead involved in any network connection, but you should be able to get 50% of the rated throughput for the slowest link, and that means you should get MUCH faster speeds on the gig-to-gig connection and considerably faster speeds on the other one.

It is possible for other wireless networks to cause you to have speed problems, but that sort of problem should show up differently, mainly in poor signal strength indications. It seems that there's something going on here.

Here's something to try: delete your AirPort location; if you have only the Automatic location, make a new one and let it keep all its defaults. Now, using that location, see what sort of speed you get wireless. Repeat with your built in ethernet connections on both computers, and check speeds again.

[mduell]

Apple's wireless hardware isn't known for being the best, but there is some other issue on your network... with two random PCs and a decent 100BT switch I can get 9-10MBps between machines easy, so for you to be getting 6 on gigglebit is a sign of some other problem.

[ginoledesma]

On my network, my MacBook can push 1.8MBps over wireless, but on a wired connection I can easily get 6-8MBps over a 100Mbps switch, so something is really messed up in your end. One thing I run into occasionally with wireless is the signal interference, so I change the channel as needed.

Several things you can do is figure out if there are packets being dropped during the file transfer. ping, tcpdump, and others will be very helpful in diagnosing your connection problems.

[kupan787]

I will try deleting my location, and doing some more testing. Of note:

The gig to gig test is a PowerMac G5 to a PC (AMD 2500+, XP SP 2). The ethernet on the PC is just on the motherboard. I am doing an FTP transfer from the Mac to the PC (meaning the FTP server is running on the Mac, and I am downloading files onto my PC).

For the gig to 100baseT test, it is a PowerMac G5 to a Powerbook G4 (12", 867MHz). Both Macs are running the latest OS X (10.4.8). In the Network settings, both have Ethernet set to "Automatic" in the Ethernet tab.

--------

Ok, just did the Gig to Gig test again. One change I made (other than a clean location)was to "force" 1000baseT setting on the Mac in the Ethernet tab. Results:

16.5MBps

So, more than triple what I was seeing with the "autoselect" option previously. As for the wireless test:

1.7 MBps

So this is still pretty crappy. Computer to Computer wireless:

1.5MBps - 2.0 MBps

Again, pretty crappy still. A few items to note. On my airport extreme I have the following settings:

Create Closed Network - not checked
Wireless Security - Not Enabled
Channel - 1
Mode - 802.11g only
Multicast Rate - 2 (the default)
Enable Interference Robustness - not checked
Transmitter Power - 100%

My airport is just used as a wireless AP. It is hardwired into an WRT54G linksys router (running SVEASOFT for the QoS features). I also have the MAC access control enabled (I know, I know weak security, but I live in an apartment complex, so most people don't know what a MAC address is, let alone how to snatch one and spoof it).

I doubt the router is at fault at all, or the Airport Extreme, as my computer to computer tests shows similar speeds, and very crappy at that. Any more thoughts, or suggestions?

[gradient]

nm.

[kupan787]

Ok, some further testing...

I have taken the Airport AP out of the picture, and am just using my WRT54G now for wireless+routing. With only 2 wireless clients connected, both Airport Extreme, the WRT54G is reporting that it is operating only at 36Mbps. If I force it to 54Mbps (instead of auto mode) neither of my airport extreme clients can connect (the "transmission" speed is taken from the Status page of my WRT54G). Even still, I am only able to transmit at about 950KBps (7.7Mbps) (ftp from mac to mac through the wireless router).

What really sucks is that my internet is faster than the speeds I am able to put out via the wireless right now, so I can't take full advantage. I just wonder if it is my client cards, my AP, or the fact I am in an apartment and am being bombarded with so much wifi traffic it is nuts (12 APs and counting now). Can a lot of "cross traffic" cause slow downs like I have been seeing?