Slow wlan0 compared to eth0?

Question

Note:

DNS:

• using OpenDNS

Wireless NIC:

Intel Corporation PRO/Wireless 3945ABG

Kernel module:

iwl3945

uname -r

2.6.28-11-generic

Release:

Distributor ID: LinuxMint
Description:    Linux Mint 7 Gloria - Main Edition
Release:    7
Codename:   Gloria

ip a | grep inet6:

inet6 ::1/128 scope host 
inet6 fe80::21b:38ff:fe0c:d718/64 scope link

tail /etc/modprobe.d/blacklist.conf

# blacklist ipv6
blacklist ipv6

Question

• How to improve the connection speed, to match with (or similar) to Ethernet or Win NT 5.1 wireless driver?

Answer 1

Your wireless card is 802.11a/b/g, which has a max physical layer throughput of 54 Mbit/sec. This maximum is rarely achieved in 'normal operating conditions' for most people, and you're more likely to see much slower speeds. Compared to a typical 100 Mbit ethernet card which has a max physical layer throughput of ... 100 Mbit, you should not expect to reach the same level of performance.

What you gain in mobility and convenience with Wireless is supposed to outweigh the speed/performance benefits of being tied down with ethernet. Bondage puns unintended, but channel bonding puns implied.

Fwiw, IPv6 is not primarily intended to provide performance gains, it's main benefit is increased address availability. Disabling it may or may not affect performance.

There's a myriad of reasons for differences in Windows vs Linux drivers, not least of which is whether the vendor contributed the driver to Linux. You may be able to tune kernel network parameters with sysctl, or by manipulating the driver module load options. Finally, the driver from Windows may load on Linux using NDISwrapper.

For more information on sysctl:

• On Ubuntu and Debian systems the file /usr/share/doc/procps/examples/sysctl.conf is heavily commented.
• The man pages for sysctl and sysctl.conf may be helpful.
• Some performance settings on Ubuntu with sysctl.

There seems to be more information about sysctl on Linux 2.4 kernels than 2.6. I'd have to go delving into the Linux source code documentation for more.

Answer 2

If your Access Point has another device on it that can only do B speeds, then it's possible that it's stepping down all of its clients, including your g card.

Might want to enforce g on the AP if that's an option.

Answer 3

I would recommend doing a site survey of the electromagnetic spectrum. If someone is using the same frequencies that would explain the performance issues you are having. I discussed an issue similar to this in another thread. Here is the answer I gave to a similar question.