Urgent question regarding Transmit/Receive link rate

[TJones2]

Been searching for an answer to this for weeks and haven't found anything.

Early this month I bought an Asus RT-N66U. When checking speed using my wireless adapter app, it tells me my Transmit Link Speed is 300Mpbs at 40mhz and 144Mbps at 20mhz. But my Receive Link Speed is 240 (or less)Mbps at 40mhz and 72Mbps 20mhz.

With my old Linksys WRT54g, its always a consistent 54Mbps up and down. I seem to recall my previous Linksys wireless "n" routers were also consistent, just unreliable (they both died).

Need to know if this is normal or that there might be something hardware related? I have tried different wireless adapters with the same result. Today is the last day I can return it or swap it out so its kind of urgent.

 

[JackMDS]

Measure the real Transfer (Copy File size/time).

The numbers that you see comes from are printed tables of the chipset inner clock speed in the Drivers and Not real perfromence.

Real performance and its deviations are more a variable of the is environment rather then the deviations in the core chip set frequency.

 

[TJones2]

Thanks but I'm not sure what you said.

When I tested copy time between two computers, when running at 40mhz, the transmit was around 120mbps, when receiving it was around 100mbps.

The Transmit Link Speed is always solid, which I think fits with what you said, but the Receive jumps around between about 170 and 260mps at 40mhz. So it doesn't seem to be reading off a page. Just not sure why Transmit would be "stronger" than Receive?

I just want to make sure its actually working as it should be since this is the last day I can swap it out.

 

[JoeMcJoe]

Your router is working fine.

Advertised max speeds are not achievable, unless you live in a test lab...?

 

[TJones2]

Your router is working fine.

Advertised max speeds are not achievable, unless you live in a test lab...?

Yes. I know. But I'm asking about the Link Speed. Why would the Transmit Link Speed be giving me the theoretical full speed, but the Receive Link Speed is about half that?

 

[JoeMcJoe]

Tx and Rx speeds usually are different. The speeds change all the time, quicker than is reported.

 

[TJones2]

Tx and Rx speeds usually are different. The speeds change all the time, quicker than is reported.

Just don't know why the Transmit is way more than the Receive Link Rate, consistently. I'd think they'd be close or the same. Nothing seems to change that. Again, I'm talking Link Rate here, not transfer or throughput rate.

 

[ch33zw1z]

Don't worry so much about what it's telling you, instead worry about what you're actually getting:

1. Test your internet connection at www.speedtest.net

2. Transfer some files between workstations and see what you're getting for speeds

3. Use iperf to test throughput outside of file transfers.

 

[JackMDS]

That is remanding the Posts coming from people that ""Dare"" to look at their Cable Router's Log and see all the outside random hits getting scared that the whole Interent is after them.

I.e., I do not get it what functionally is troubled with your Wireless and why it is urgent to deal with it.

 

[TJones2]

Its urgent because today was the last day I can swap it if there's a problem. Anything with a router that doesn't look right causes me concern because I've had two "n' routers die on me in the past year. It looked to me like the Receive radio had issues as its so far below the Transmit.

 

[TJones2]

Don't worry so much about what it's telling you, instead worry about what you're actually getting:

1. Test your internet connection at www.speedtest.net

Yes, done that many times. My internet is 20Mbps which even my 54g router handles with ease.

2. Transfer some files between workstations and see what you're getting for speeds

Tried that a few days ago, got around 110-115Mbps when transmitting, 90-100Mbps when receiving, this was consistent with the Link Speed.

3. Use iperf to test throughput outside of file transfers.

Thanks, I'll try that.

 

[JackMDS]

Hmm... Transmitting and receiving is done between different devices each one with its own Wireless card. Each card has its own Transmitter and its own Antenna.

Why the action of both should be exactly the same especially when its involvs MIMO.

 

[TJones2]

Put my WRT54g back on, and all the problems vanished. The lagginess I've been experiences went away (the reason why I started checking out latency, etc). Took the router back.

Thanks again for the help Joe and ch33zw1z!

 

[mindbomb]

i think the lowered receive rate is because the adapter doesn't support a shortened guard interval, but the router does.

 

[JoeMcJoe]

You did need to give us more information about the wireless networks in your location.

Introducing 40 Mhz 802.11n to the 2.4 Ghz band will usually introduce problems, unless you live in the middle of nowhere, stick to 802.11n/g with 20 Mhz.

A WRT54G is a great router, I still use one today in one location running TomatoUSB.

The Asus RT-N66U is also a great router, very capable.

 

[TJones2]

I tried the n66u in 20mhz and in 40mhz, the receive band appeared 'weak' in both. All I can say is for what I used it for (access the internet) the 54g is far better. All the problem of slowly downloading webpages and missing images are now (mostly) gone. I'm thinking their was either a bug in the n66u I had, or it just didn't play nice with my wireless adapters (both adapters it turns out are basically the same, just different trade names).

 

[drebo]

Your wireless device probably has worse noise cancellation than your router. This would cause the signal to noise ratio on the wireless device to be low and thus the modulation will change to compensate. This is normal operation with wireless. The wider the bandwidth, the more pronounced the difference.

 

[TJones2]

My need for the router wasn't as great as the lure of a great deal (got it for $99cdn). Since it disappointed, I took it back intending to try another, but the Staple's people were so bad, I changed my mind and took the refund they offered. I'll start all over again once we're moved and settled (we're moving in six months, I'll have a better idea if going fully wired is practical, which is my preferred option).