TomatoUSB

So I was doing a bit of speedtesting on my network and found a rather irksome anomaly. Take a look at these speeds:

HTTP download from kernel.org over ethernet: about 6MB/s (max my cable modem can do)
HTTP download from a local computer (on ethernet) over wifi: about 4-5MB/s
HTTP download from kernel.org over wifi: about 1.5MB/s

Pulling from the internet over wifi is dramatically slower than the other two cases, which makes no sense to me, as the other two cases clearly show that both internet->router and router->wifi are capable of several times what internet->wifi is actually achieving.

Any ideas what could be causing this discrepancy in speed? I'm using "Tomato Firmware v1.28.7486 MIPSR2-Toastman-RT K26 USB Ext" on an ASUS RT-N16.

I've recently added a linksys E2000 to my network[1], and it is showing the same issue. A wireless client can pull around 12MB/s from another (wired, gigabit) computer on the LAN, but only 2-3MB/s from kernel.org.

I've tried toggling QoS on and off, to no effect. I've also tried most of the different options under advanced->wireless, which resulted in only small changes that affect both local and internet transfers, usually negatively.

The output of 'nvram show' for both routers is here: h__ps://gist.github.com/057938acde099e6a93cf (sensitive info has been replaced with [MASKED]).

[1] The E2000 is acting only as a 5ghz access point, and is wired in to the RT-N16 which does all the actual routing to the internet. The E2000 is running "Tomato Firmware v1.28.7489 MIPSR2-Toastman-RT K26 Std".

It sounds very similar to an issue I reported here: www.linksysinfo.org/index.php?threads/its-not-supported-by-tomato-yet-but-lets-talk-about-the-new-asus-rt-n12-b1.35573/#post-174286

Likely a wireless driver issue I would guess.

That does indeed seem similar.

I tested having the E2000 do the routing today as well and it's exhibiting the exact same behavior, so this doesn't even appear to be specific to the ASUS routers. :/

This should have occurred to me before, but I just tested speeds running the wireless download from the internet through the wired computer (using ssh -L), and it's getting the full 6MB/s. It's faster to run the data though the router, to another computer, and back to the router out to the internet, than it is to just go through the router once. Something is seriously wrong here. :/

EDIT: can't reproduce this effect anymore… wierd

Does the same problem exist when downloading from the LAN via wireless? As in computer A (wireless) — router — computer B (ethernet).

VanillaXtract: No it doesn't, as I noted in my very first post. The only case that triggers it as far as I can tell is internet — router — computer (wireless).

a few possibilities.

1) Wireless between your computer and router uses same frequency, so they are required to take turns (aka half duplex) vs wired Ethernet's full duplex. There is also a delay when you change in direction.

Router -> PC: Data
PC -> Router: ACK packet
Router -> PC: Data

Because of the waiting/half duplex, the wireless link is adding latency. In the case of your LAN, the latency from your PC isn't much, but on an external website it adds up. May be this extra latency slows down the data?

2) During these dead time and ack packets you are not transferring payload data.

3) interferences on your wireless channel?

Neet_Studio:

1-2) If that were the case though, then wouldn't running multiple downloads in parallel end up using the whole bandwidth, since they could fill in each other's dead spaces? I get the same speeds with anywhere from 1 to 16 simultaneous download threads. The speed does go up dramatically if I turn on frame bursting - about 5.5MB/s out of my maximum 6MB/s, instead of a mere 2.5MB/s - but I'd prefer to leave frame bursting off since it doesn't work as nicely with multiple clients.

3) There's nothing else using the 5ghz channel I've chosen as far as I can tell, and if that were the case it would apply equally to both local lan and wan traffic, no?

I was having this problem with my Tomato router, and it turned out that even though QoS was turned off, the WMM (Wi-Fi Multimedia) option was turned on under the Advanced -> Wireless settings. Once I turned that off, it fixed the problem.