How to Solve Performance Problems in a Slow LAN

A local area network connects one or more computers in a small geographical area to the Internet. Certain network or network adapter settings can cause performance problems resulting in slow Internet speeds; Transmission Control Protocol Auto-Tuning, for example, can result in slow LAN connections on computers with older network equipment. Changing the network settings in the Network and Sharing Center -- a built-in Windows module that allows you to review and control your Internet connection -- can resolve slow speeds on the LAN.

Instructions

1. Click "Start." Input "cmd.exe" into the search box. Right-click "cmd.exe," then click "Run As Administrator."

2. Input "netsh interface tcp set global autotuning=disabled" into the command-line interface. Press "Enter" to disable TCP Auto-Tuning.

3. Click "Start." Right-click "Network." Select "Change Adapter Settings" from the left pane. Right-click the wireless network adapter, then click "Properties."

4. Uncheck "Internet Protocol Version 6 (TCP/IPv6)." If a website has an IPv6 address assigned, the network will attempt to connect to the website via TCP/IPv6. However, if the associated server is poorly configured, the connection will run slowly or even time out. If IPv6 is disabled, the network will automatically route through IPv4 instead. Click "OK."

5. Open the network adapter properties once again, then click "Configure." Select the "Advanced" tab, then click "Beacon Interval." Confirm the value is set to "100." Select "Wireless Mode," then select "IEEE 802.11b/g/n" from the drop-down menu. Click "OK."

6. Return to Command Prompt. Input "ipconfig," then press "Enter." Open a Web browser and type the set of numbers next to "Default Gateway" into the address bar.

7. Log in to the router Web-based configuration utility. Check the advanced wireless settings for options that could be causing performance problems with the Internet. QoS settings, parental controls and misconfigured data thresholds can all cause problems with Internet connection speeds.

Tips & Warnings

• If you're connecting to the Internet through a wired router, disable IPv6 for the wired network adapter instead.

• Router options vary from product to product. Check your router manual before making changes to the network settings. Most manuals include explanations about what each option in the Web configuration utility does.

References

• Vista Forums: Auto Tuning: TCP/IP Receive Level
• Mike's Lookout; IPv6 Will Slow You Down; Mahy 2011