Achieving Wireless N

[Michael]

Hello all,

 

I'd appreciate some advice as I'm a bit stumped as to why I can't achieve Wireless N speeds. Setup is an HP V-M200, latest firmware, currently configured as dual G/N mode. This should allow up to 130Mbps. I can only achieve 65Mbps across different devices, all with N rated adapters.

 

I then tried changing the mode on the HP V-M200 to N only @2.4GHz. Again I can only achieve 65Mbps and there's nothing else I can tweak (as far as I can see).

 

I've checked the specs of the Realtek and Intel Wireless NICs and both are capable of 130Mbps as detailed in the specs. I've updated drivers and tried creating a new SSID using WPA2 AES again all with the same results. I haven't tried N only @5GHz as neither supports this, so it would be pointless.

 

Any suggestions would be welcome!

[RTFM]

Is 130Mpbs on the spec going to be upload and download, one way or the other being 65Mbps?

 

We had Sonicwall come in to chat to us about firewalls and speaking of throughput's and he said whatever the 'spec sheet' or sales people say a firewall can do, half it as they combine upload and download to give a figure when in reality you can only do half of it each way (if that makes sense).

 

So 65 upload, 65 download would give a combined throughput of 130Mbps but you'll only ever see half that......

 

I may have explained it poorly and someone may claim i'm wrong but that is off the top of my head how the conversation went. We were talking about firewalls i know but the same may be true of wireless controllers?

Edited November 22, 2012 by RTFM

[Michael]

I've not heard that before, however I've now found another make/model of notebook with an Atheros AR938x which is capable of connecting @ 130Mbps both in 2.4GHz and 5GHz wireless N mode. Still cannot achieve the magical 300Mbps it appears!

[chazzy2501]

ok for a 2.4ghz N device to achieve 130Mbps it has to bond the channels or use 40Mhz mode. (each channel being 20Mhz) so the access point must use two consecutive channels so if you use channel 13 it bond with channel 9. ANYHOW in order to operate at 40Mhz the Access Point must be aware of devices that wont tolerate the 40Mhz width and immediately drop to unbonded mode 20Mhz. This will include any b/g client connected to the device or any access point already using a channel near or in the bonded range.

 

You can get a 300Mbps in 2.4Ghz as well this uses mimo and bonding technology but relies on the client also being mimo (one anntena to send one to recieve)

 

Really you want to move to 5Ghz and then bond 2 of those channels for 300Mbps as 2.4ghz is to congested.

Edited November 22, 2012 by chazzy2501

[Michael]

The HP V-M200 in G/N or N only mode @2.4GHz won't let you change the 20MHz channel width. You can only change it in 5GHz N mode, or set it to Auto 20/40MHz.

 

I've bought an Intel WiFi 1000 to test which operates in 2.4GHz only, but should allow 300Mbps. It's also comparatively cheap, bearing in mind schools would have to replace the adapter in every machine. 5GHz adapters are pretty much twice the price. You could argue it would still work with older G devices too.

[m25man]

Connect802 Corporation @chazzy2501 is spot on.

 

You really don't want to push your 2.4Ghz clients beyond 65Mbps N your just going to compound the overcrowding issue of the band and create conditions likely to decrease throughput and increase packet loss.

5Ghz N and eventually .ac is the only way forward with Wifi link speeds.

 

Dual band 5Ghz cards in your laptops is not going to help you if they don't have the antennas built in either.

[psydii]

Given what happens when you've got overlapping g/n 20Mhz /40 Mhz unmanged BSSIDs with routers/aps of variable quality, throw in a few 'invisiable clients' into the mix, and I can't help but suspect that 802.11ac is going to quite quickly become a mess that makes the current state of the 2.4 band look like clear air.

 

Though to be fair I haven't read up on the spec, maybe if it frequency hops like bluetooth it might not be a disaster. I'm still trying to get my head around 802.11-abgn interop

[psydii]

By the way you can get 65Mbps-130Mbps without channel bonding in 2.4, as long as you've got 2x2 radios.

 

It is the general wisdom that you don't want (and in many cases can't) go to 40MHz to double your bandwidth due to the overcrowding in the ISM spectrum.