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xmit
join:2004-04-03
|  [wireless] Bad throughput between WRT54G and Netgear WG511
Hi,
the throughput of my WLAN is bad:
Packet size 1k bytes: 2662 KByte/s Tx, 2840 KByte/s Rx.
Packet size 2k bytes: 2739 KByte/s Tx, 2572 KByte/s Rx.
Packet size 4k bytes: 2754 KByte/s Tx, 698 KByte/s Rx.
Packet size 8k bytes: 2633 KByte/s Tx, 2777 KByte/s Rx.
Packet size 16k bytes: 2744 KByte/s Tx, 133 KByte/s Rx.
Packet size 32k bytes: 2629 KByte/s Tx, 2855 KByte/s Rx.
or even worse:
Packet size 1k bytes: 2680 KByte/s Tx, 65 KByte/s Rx.
Packet size 2k bytes: 2707 KByte/s Tx, 69 KByte/s Rx.
Packet size 4k bytes: 2598 KByte/s Tx, 50 KByte/s Rx.
Packet size 8k bytes: 2660 KByte/s Tx, 2097 KByte/s Rx.
Packet size 16k bytes: 2616 KByte/s Tx, 2138 KByte/s Rx.
Packet size 32k bytes: 2602 KByte/s Tx, 2143 KByte/s Rx.
These measurements where made with netio -t, v1.23.
The netio server is a PC (PIII 800MHz), that is directly connected via fast Ethernet to a Linksys WRT54G WLAN Router. The router's firmware is 2.4.20-h.Wifi-box.net.
The client is a IBM Thinkpad X24 notebook (PIII 1.1GHz) equipped with a Netgear WG511 card. It uses the linux 2.6.5-rc1-mm1 kernel drivers and 1.0.4.3.arm firmware. No other devices where attached to that network.
As you can see, the receive rate breaks down to 50 KByte/s quite often. This seems not to be related to the packet size, the signal quality or distance between client and route. I tried between 1 and 10 meters several times.
Here is what iwconfig says:
eth2 IEEE 802.11b/g ESSID:"xxxx"
Mode:Managed Channel:5 Access Point: 00:04:FE:7B:F4
Bit Rate:54Mb/s Tx-Power=31 dBm Sensitivity=20/200
Retry min limit:8 RTS thr:2347 B Fragment thr:2346 B
Encryption key:xxxxx Security mode:restricted
Link Quality:170/0 Signal level:-24 dBm Noise level:-185 dBm
Rx invalid nwid:0 Rx invalid crypt:0 Rx invalid frag:0
Tx excessive retries:0 Invalid misc:0 Missed beacon:0
dmesg shows nothing abnormal:
...
Loaded prism54 driver, version 1.0.2.2
...
eth2: prism54 driver detected card model: Netgear WG511
...
eth2: islpci_open()
eth2: resetting device...
eth2: uploading firmware...
eth2: firmware uploaded done, now triggering reset...
...
Assuming someone else called the IRQ
The last line is repeated nine times, but that was before I started netio.
I get more stable results with the same environment but the notebooks's build in 802.11b device. RX/TX througput is stable around 600KBytes/s. Maybe there is a conflict between WG511 and this prism2.5 mini pci card, but I switched the router to G only mode and removed any initialization of prism2.5.
I wonder a bit why lspci denotes the WG511 as a
03:00.0 Network controller: Harris Semiconductor D-Links DWL-g650 A1 (rev 01)
but this should not be a problem.
I would appreciate any advice what I should try to get a stable receive rate with my new WG511.
I want to receive video streams, but with receive rates down to 50KBytes/s I shouldn't even think of it.  | |
RouterRooter
join:2001-11-22
Rockville, MD
| Hi xmit,
I don't have the time (or background) to parse your detailed note (sorry), but I do have a WRT54G and a WG511 and get pretty good throughput according to DUMeter and QCheck and just measuring file transfers
Infrastructure mode
WG511 / WRT54G / WG121 (USB)
Up to 14.xx mbps peak
10+ mbps average
Based on my research, these are about the highest values you'll ever get in infra mode with 54-G. Has to do with the double xmit in infra mode (to WAP, then to destination) and the relatively bad payload to gross data xmission ratio (~50%). I did a little tweaking to get up to these numbers. | |
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