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Bizarre Up vs Down & 802.11g vs 802.11n Speed Differences!

Last response: in Wireless Networking
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March 27, 2012 12:26:53 AM

This is a truly bizarre wireless puzzler, so I came here to ask the experts. I'm a knowledgeable user myself, but this is beyond me. The problem relates to truly terrible download speeds (with simultaneously excellent upload speeds!) using either of two different Wireless-N USB 2.0 adapters, even though the 802.11g connection to my laptop is outstanding and the wireless router seems to be working perfectly!?

My wireless router is a Linksys WRT160N, which supports 802.11b, g, and n. Yet while my laptop's 802.11g wireless connection is awesome (24 Mbps dowloads, 9 Mbps uploads), the download speeds of two different manufacturer's 802.11n USB 2.0 adapters is mind-bogglingly awful, usually around only 0.5 to 0.8 Mbps (while strangely they both provide upload speeds of about 9 Mbps, just like the laptop).

The laptop is a Dell 1526, and its internal wireless adapter is a Dell 1390 WLAN (see specifications here: Dell Wireless 1390 WLAN Mini Card specifications). Note that this only supports 802.11b & g (which I first learned when I set my wireless router to use "n only", whereupon the laptop could no longer connect). It's running 32-bit Windows 7 Home Premium. I use Win7's wireless zero config rather than any third-party (such as Dell's) software.

The two different, recently purchased, Wireless "n" USB 2.0 adapters I own and have tried are:

(1): IOGear GWU625 Compact Wireless-N USB Adapter. For the intended use under XP Pro, I previously used IOGear's wireless software/driver, but have since switched to Realtek's (both latest driver and management software).

(2): Medialink MWN-USB150N Wireless N USB Adapter. Under XP Pro, I use Medialink's driver and software.

Both of the Wireless-N USB adapters are rated at 150Mbps maximum send/receive throughput. Also, both of them support 802.11b & g (as well as n).

They both produce virtually identical (and bizarre) results on all computers. I've tried the two of them on different desktop computers (with Intel motherboards that lack on-board networking) running 32-bit XP Pro/SP3 as well as the very same Dell laptop (after disabling the on-board wireless) under Win7 and I get pretty much the same weird results: Terrible download speeds (less than 1 Mbps) with excellent upload speeds. Note also that I tested them all in exactly the same position, 10 feet from the router, so it's not a radio or interference issue. (However, every once in a while I can get about 6-8 Mbps downloads on the wireless n adapters for several minutes before it drops back down to less than 1.)

My router is a Linksys WRT160N Ultra RangePlus Wireless-N Broadband Router, hardware rev 1.0, with the latest firmware (Ver.1.02.11).

When I first discovered this problem, I tried to tweak many of the router's settings to improve performance, but the performance was unchanged (neither better nor worse). Afterward I reset them to the factory defaults, which is where they are now.

I then downloaded and ran TCPOptimizer and followed the suggested basic instructions, but the terrible download rates remain unchanged.

So my general question is: Why am I getting such ridiculously slow download rates with both of these Wireless-N USB adapters while at the same time the 802.11g laptop gets vastly faster download rates?

Does it have something to do with 802.11g versus n (which I thought was supposed to be faster)? Or is there something else that's behind this very strange situation?

I desperately need your help, folks - thanks!

===================================================

Here are some technical details that might be of interest:

Xirrus Wi-Fi Inspector's Wireless Testing Results:
IoGear Wireless-N USB Adapter
25-Mar-2012

Adapter: Realtek RTL81891SU Wireless LAN 802.11n USB 2.0 Network Adapter
BSSID: Cisco-Linksys 4B:6F:95
Channel: 1
Signal: -45 dBm
Mode: 802.11n
Default Encryption: AES-CCMP
Default Auth: WPA2/PSK
Vendor: Cisco-Linksys (Linksys WRT160N)
Frequency: 2412
Network Type: Access Point


Signal History Over Time: Extremely Stable (no visible changes over about a 40-minute period)

Download Speed: 0.63 Mbps (Xirrus uses speedtest.net)
Upload Speed: 8.94 Mbps

Quality Test/Ping Test
Grade: B
Packet Loss: 0%
Ping: 47 ms
Jitter: 9ms

------------------------------

This is the output from IPCONFIG /ALL:

Windows IP Configuration

Host Name . . . . . . . . . . . . : xxx
Primary Dns Suffix . . . . . . . :
Node Type . . . . . . . . . . . . : Unknown
IP Routing Enabled. . . . . . . . : No
WINS Proxy Enabled. . . . . . . . : No
DNS Suffix Search List. . . . . . : hsd1.xx.comcast.net.

Ethernet adapter Local Area Connection:

Media State . . . . . . . . . . . : Media disconnected
Description . . . . . . . . . . . : Intel(R) 82567LF-2 Gigabit Network Connection
Physical Address. . . . . . . . . : 00-xx-xx-xx-xx-xx

Ethernet adapter Wireless Network Connection:

Connection-specific DNS Suffix . : hsd1.xx.comcast.net.
Description . . . . . . . . . . . : Realtek RTL8191SU Wireless LAN 802.11n USB 2.0 Network Adapter
Physical Address. . . . . . . . . : xx-xx-xx-xx-xx-xx
Dhcp Enabled. . . . . . . . . . . : Yes
Autoconfiguration Enabled . . . . : Yes
IP Address. . . . . . . . . . . . : 192.168.1.102
Subnet Mask . . . . . . . . . . . : 255.255.255.0
IP Address. . . . . . . . . . . . : xxxx::xxx:xxxx:xxxx:xx%6
Default Gateway . . . . . . . . . : 192.168.1.1
DHCP Server . . . . . . . . . . . : 192.168.1.1
DNS Servers . . . . . . . . . . . : xx.xx.xx.xx
xx.xx.xx.xx
xxxx:0:0:ffff::1%1
xxxx:0:0:ffff::2%1
xxxx:0:0:ffff::3%1
Lease Obtained. . . . . . . . . . : Sunday, March 25, 2012 11:15:43 AM
Lease Expires . . . . . . . . . . : Monday, March 26, 2012 12:15:43 AM

Tunnel adapter Teredo Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . :
Description . . . . . . . . . . . : Teredo Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : FF-FF-FF-FF-FF-FF-FF-FF
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : xxxx::ffff:ffff:fffd%5
Default Gateway . . . . . . . . . :
NetBIOS over Tcpip. . . . . . . . : Disabled

Tunnel adapter Automatic Tunneling Pseudo-Interface:

Connection-specific DNS Suffix . : hsd1.xx.comcast.net.
Description . . . . . . . . . . . : Automatic Tunneling Pseudo-Interface
Physical Address. . . . . . . . . : xx-xx-xx-xx
Dhcp Enabled. . . . . . . . . . . : No
IP Address. . . . . . . . . . . . : xxxx::5efe:192.168.1.102%2
Default Gateway . . . . . . . . . :
DNS Servers . . . . . . . . . . . : xxxx:0:0:ffff::1%1
xxxx:0:0:ffff::2%1
xxxx:0:0:ffff::3%1
NetBIOS over Tcpip. . . . . . . . : Disabled

-----------

Both computers I'm trying to use the Wireless-N USB adapters are running 32-bit XP Pro/SP3
Type: Cable Internet
My ISP: Comcast - 50 Mbps max
Modem: Motorola SurfBoard
Router: Linksys WRT160N
a c 75 F Wireless
March 27, 2012 7:10:03 AM

what happens when you set the usb wifi adapters to run in G-mode?

are you using a USB 2.0 port?
March 27, 2012 9:06:10 AM

Emerald said:
what happens when you set the usb wifi adapters to run in G-mode?

are you using a USB 2.0 port?


Hi, Emerald! Thanks for your reply!

First, the adapters as well as the computers both support USB 2.0.

I've now figured out how to force my wireless router to broadcast only 802.11g signals. After a few tests, the download speed did rise substantially to about 12 Mbps! I'm going to want to keep testing for a day or two to confirm that the download speeds stay that way (although that's still only about half of my laptop's download speeds), and if it keeps up I guess that'll be (barely) good enough.

So what we apparently have is a router transmitter problem in 802.11n mode, since the download speeds are bad but the upload speeds are great (hence the receiver is working fine). So unless you have any better suggestions, I suppose I'll just have to replace the wireless router...

Related resources
a b F Wireless
March 27, 2012 10:14:48 AM



I'm sure you've already tried this but can you check the MediaType setting in the adapters configuration and experimented with changing them, particularly if they're set to Auto? 10/100 Full Duplex might do better.

March 28, 2012 7:05:34 AM

Saga Lout said:


I'm sure you've already tried this but can you check the MediaType setting in the adapters configuration and experimented with changing them, particularly if they're set to Auto? 10/100 Full Duplex might do better.



Thanks to you also, Saga Lout, for your reply!

I looked and looked, but I could find no settings anywhere either in Windows or in the two USB adapter's wireless manager software regarding "Media Type" or anything related to "10/100". Isn't that only related to Ethernet connections? Would you help me resolve my confusion about this?

Thanks again.
a b F Wireless
March 29, 2012 6:58:39 AM



Sorry, my bad - you're quite right, of course and it applies only to the wired side. With the USB N adapter removed, may I see a Xirrus report on the Dell's own adapter?



!