WRT54G2: Wireless rate drops to 2 Mbps or 1 Mbps

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wouter
DD-WRT User


Joined: 05 Oct 2008
Posts: 96

PostPosted: Sat Feb 05, 2011 16:58    Post subject: Reply with quote
Still struggling with wireless rate drops (down to 1 or 2 or 5.5 Mbps in the WRT54GL 1.1 router).
For the heck of it I went back to Linksys stock firmware v4.30.11_012_ETSI_EN, as I believed to remember that I did run that for quite a while without major issues.
I have suspected temperature issues with the WPC54G (PCMCIA) adapter in my notebook.
To my surprise it seems that the temperature of the WPC54G adapter in my notebook stays cooler (less warm) then with either DD-WRT of Tomato-USN firmware in the router.
No clue yet what is different besides the router now runs an older Linksys ETSI (European, with 13 channels) variant stock firmware. Router settings as far as possible are equal as with other firmware versions (G only, WPA2 Personal with AES, same channel).
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gopalmm2
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Joined: 18 Oct 2010
Posts: 7

PostPosted: Fri Feb 11, 2011 19:05    Post subject: Reply with quote
I'm getting fast wireless rate 24-36 with the build I mentioned, it works really well.
At 40mW, the speed drops at times to 5.5, but most other times it remains at 36. At 100mW the speed is almost always constant at 24.
This is of course in the WRT54G2V1. May be you can try the same build and the TX power I used.
wouter
DD-WRT User


Joined: 05 Oct 2008
Posts: 96

PostPosted: Sat Feb 12, 2011 13:44    Post subject: Reply with quote
A week passed by running the older Linksys stock firmware without issues and no reboots required.
Sometimes the wireless rate (shown in the taskbar of the clients) goes down a little (to 48 or 36 Mbps, I have even briefly seen 5 Mbps), it allways recovers within short time.
For now I get convinced again it is the router + 3th part firmware that is causing wireless rate issues. Maybe it is that these 3th party firmware versions have difficulties with recovering from a low wireless rate (maybe caused by a mobile client such a IPod or Smart phone with bad receiption at some location in the house, or while being carried out of the house?).
heppy1
DD-WRT Novice


Joined: 13 Feb 2011
Posts: 4

PostPosted: Fri Feb 18, 2011 6:48    Post subject: Reply with quote
My router is a WRT54G-TM with 14929 special mega. I have about 10 wireless clients in the house, from smartphones to laptops and desktops with a variety of wireless adapters from B to N.
My router is set up according to the Redhawks suggestions.
Trying to figure out my speed problems I noticed the following:
Running my ISPs speed test with any of the G or N clients I get a speed of about 15Mbps which is as it should be. With one of the B adapter laptops I only get 3.5Mbps,which is far below a B adapter's ability. So I tried to run the speed test simultaneously with a B and G laptop and I only got about 1Mbps on each of the 2 laptops. So there seems to be significant interference there which at times, if a B adapter has significant traffic, will slow down the whole wireless network.
Not sure if there is any fix for that.
wouter
DD-WRT User


Joined: 05 Oct 2008
Posts: 96

PostPosted: Fri Feb 18, 2011 13:07    Post subject: Reply with quote
The 802.11B specification says 11 Mbps, practical throughput will be about half of that at maximum, so 3.5 Mbps as you indicate is not that bad, also if you count that the wireless network is shared.
802.11B/G routers have only one transmitter and receiver, in other words they can only send at one speed at the time. Practical that means it will be the lowest speed counted over all connected clients (one client with a slow adapter or bad receiption will pull the whole wireless network down). In addition, the bandwith is shared with all clients, in theory if all your 10 clients send and receive at the same time, each client will get 1/10 of the total bandwith.
I strongly suggest to get rid of the B client(s) first.
With your number of clients, you may even consider a full N wireless network.
heppy1
DD-WRT Novice


Joined: 13 Feb 2011
Posts: 4

PostPosted: Sun Feb 20, 2011 1:49    Post subject: Reply with quote
Ok, I eliminated all B adapters in my network. It is all good now, no more weird slow speeds as experienced before. Having mixed B and G adapters in their network might be the problem of many people here complaining about low rates.
When the B adapters had large downloads that slowed the whole network down to 1 to 2Mbps.
edjal
DD-WRT Novice


Joined: 30 Jun 2009
Posts: 16

PostPosted: Fri Apr 01, 2011 9:58    Post subject: Reply with quote
This thread started on March 2009 and nobody has found a solution yet.

I have done some research about the chip the WRT54G2v1 uses (Broadcom BCM5354) and found that the Asus WL-500gPv2 had an issue with the clock rate of this chip (see: http://www.dd-wrt.com/wiki/index.php/WL500G_Premium_v2#Clock_Timing_Bug). From what I have understood, it appears that either the chip is running overclocked at 240 MHz or it really is a 240 MHz chip with a core frequency of 200 MHz.

Just to try it and see if it solves somehow the wireless rate drop problem: why don't we underclock the chip to 200 MHz? It should be safe... I don't have any reason to assure that it will improve things, but given the fact that this issue persists after 2 years, I think we could give it a try.

AFAIK, this code should do the trick:

Code:
nvram set clkfreq=200
nvram commit
reboot


However, I haven't tried it as I don't have a JTAG cable in case the underclocking bricks the router. Is anyone willing to try it and share the results with us?

Thanks.
wouter
DD-WRT User


Joined: 05 Oct 2008
Posts: 96

PostPosted: Sun Apr 03, 2011 18:28    Post subject: Reply with quote
It is now April 03, 2011; on Sat Feb 05, 2011 I did load Linksys stock firmware v4.30.11_012_ETSI_EN back into my WRT54GL.
Since then the router runs like it should, lean and mean with DHCP wireless clients only (three desktop PC's, one laptop, a PS3 and various mobile devices such as IPod Touch, Windows Mobile 6.5 and Android smartphones).
Two times I had the issue that one of the PC's lost connection (ipconfig /renew to fix that).
No wireless rate drops (not other then expected due to one of the mobile clients to be nearly out of range).
The conclusion is simple for me.
Despite I do miss the advanced features of third party firmware, this stock version works stable for me, which counts to keep the family happy.
edjal
DD-WRT Novice


Joined: 30 Jun 2009
Posts: 16

PostPosted: Mon Apr 04, 2011 11:04    Post subject: Reply with quote
OK, I have finally tried the underclocking by myself and it has given no results:

Code:
system type             : Broadcom BCM5354 chip rev 2
processor               : 0
cpu model               : BCM3302 V2.9
BogoMIPS                : 239.20
wait instruction        : no
microsecond timers      : yes
tlb_entries             : 32
extra interrupt vector  : no
hardware watchpoint     : no
VCED exceptions         : not available
VCEI exceptions         : not available


Perhaps the clock rate is coded in the CFE?

Anyway, as other users have written, it seems that reverting back to stock firmware is the only option to get rid of the annoying wireless drops, at least for this router.
pablowest
DD-WRT Novice


Joined: 03 Apr 2011
Posts: 3

PostPosted: Wed Apr 06, 2011 3:17    Post subject: Reply with quote
Good results. Thanks for giving me information about that application.
hiluke
DD-WRT Novice


Joined: 18 Apr 2011
Posts: 10

PostPosted: Mon Apr 18, 2011 6:13    Post subject: Reply with quote
Found this thread from the same issue I am having on my Asus WL-520gU.

Build 16758M NEWD Eko (previously on 15508M NEWD Eko), wireless set to G only, channel 1, TX power 28mW, CTS disable, bluetooth coexistance enable, TCP/UDP timeout 120, frame burst disable, afterburner disable, beacon interval 50.

One wireless client with a RaLink chipset, a fair distance away, Signal Quality usually sitting around 25% in DD-WRT.

I'll recap my understanding:
By default, the 'Transmission Fixed Rate' is set to Auto, and on this setting, it will adapt to the environmental constraints and is meant to set the rate to the fastest it can while still being stable.

I have tried TX Power adjustments from 17mW to 251mW, with no noticeable change to rate (and only slight changes in signal quality).

When I first boot up the router, this client happily connects at 36Mbps+ and I get throughput of over 1MB/s on my internet connection easily.
However, within minutes, this drops off to 5.5Mbps (~150KB/s throughput) and doesn't go back up.

I have set the 'Transmission Fixed Rate' to 24Mbps. This will be OK for my internet connection. I don't want to push it up too high, because I understand if the client can't actually reach the higher rate, it won't be able to connect at all.

I am not having any problems maintaining the connection at this rate.

What I don't understand is why when I force it to stay at this rate, there are no issues, however when I let it pick the rate (Auto), it says 5.5Mbps is the best it can do.

Any tips?
oxygenx
DD-WRT Guru


Joined: 11 Nov 2007
Posts: 566

PostPosted: Mon Apr 18, 2011 9:10    Post subject: Reply with quote
hiluke wrote:

What I don't understand is why when I force it to stay at this rate, there are no issues, however when I let it pick the rate (Auto), it says 5.5Mbps is the best it can do.

If you have a high noise level, there is nothing you can do about it except avioiding it.

_________________
Router: WNDR3300 (wl0: n-Only 5Ghz, WPA2-AES, wl1: g-Only, WPA-Mixed-Mixed)
WDS Node 1: WNDR3300 (wl0: n-Only 5Ghz, WPA2-AES, WDS-connected Router, wl1: g-Only WPA-Mixed-Mixed)
WDS Node 2: WRT54GL (g-Only, WPA-Mixed-Mixed WDS-connected to Router)
Modem: Cisco EPC3202
clients: Notebook 1, D-Link 323, PS3 Slim, Kathrein UFC960 connected to WDS Node 1 via Gigabit Switch. Notebook 2, Deskjet 6980 connected to WDS Node 2
wouter
DD-WRT User


Joined: 05 Oct 2008
Posts: 96

PostPosted: Thu Apr 21, 2011 15:57    Post subject: Reply with quote
hiluke wrote:
...
I'll recap my understanding:
By default, the 'Transmission Fixed Rate' is set to Auto, and on this setting, it will adapt to the environmental constraints and is meant to set the rate to the fastest it can while still being stable.

I have tried TX Power adjustments from 17mW to 251mW, with no noticeable change to rate (and only slight changes in signal quality)...

Any tips?

Increasing the TX power is still the Router (Access Point) side only. You should also increase the TX power at the Client (most times a PC) end to get significant better results, which usually is not possible.
As allready mentioned by oxygenx, you need to make sure to get a better Signal Noise Ratio (SNR).

The issue I suspect with DD-WRT is that the wireless rate does not allways increase when SNR gets better or after the "weak" Client is totally gone.
hiluke
DD-WRT Novice


Joined: 18 Apr 2011
Posts: 10

PostPosted: Tue May 10, 2011 0:26    Post subject: Reply with quote
wouter wrote:

Increasing the TX power is still the Router (Access Point) side only. You should also increase the TX power at the Client (most times a PC) end to get significant better results, which usually is not possible.
As allready mentioned by oxygenx, you need to make sure to get a better Signal Noise Ratio (SNR).

The issue I suspect with DD-WRT is that the wireless rate does not allways increase when SNR gets better or after the "weak" Client is totally gone.


Thanks for the replies.

So this particular PC is connected 100% of the time.
In my RaLink UI on the PC I can change the TX power (25%, 50%, 75%, 100% or Auto). It is set to Auto, and other settings didn't seem to change much.

The Signal Quality in the router is reporting this PC as 25-30%. (Currently, Signal -71, Noise -92, SNR 21, Signal Quality 28%)

On my PC, in the RaLink UI, I see the following stats:
Link Quality: 92%
Signal Strength: -68dBm
Noise Strength: -103dBm

What I don't understand is why I can set the router to maintain a 24Mbps connection speed, and not have any issues, yet on auto, it drops to 5.5Mbps.

Thanks.
NPerez
DD-WRT Novice


Joined: 10 May 2011
Posts: 1

PostPosted: Tue May 10, 2011 1:30    Post subject: Reply with quote
Same here. I struggled with 1-2mbps speeds for a week. Tried changing the tx power, among countless other settings that people have recommended. Setting it to a fixed 54mbps caused wi-fi to stop working entirely.

Today, I decided to try fixing it at 24mbps and was surprised to see that everything is finally working smoothly. A speed test confirms that my down speed is now about 10 times higher.

So that's the only solution right now, as far as I can tell. Hopefully someday the issue will be fixed so we can set the rate to auto, but I'm just happy to not have to flash back to the awful stock firmware.
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