Symptom Possible Items to Check Typical Solution Cause. Intermittent Wired: Defective


 

Intermittent Wired: Defective

 

connectivity Ethernet cable or

 

damaged RJ-45

 

plug or jack.


 

Check cable con- Replace defective cable. nections and condi-

 

tion.


 

  Wireless: Low Check the signal Look for interference sources
  RF signal. strength (number near the router/access point
    of bars) on the or between the router/access
    devices with inter- point and devices.
    mittent connection. Adjust the antenna position.
     
      Increase the signal strength.
      Replace the wireless G router
      with a wireless N router.
       
IP conflict Duplicate IP Check the network If static IP address, make sure
  addresses. properties sheet to each device has a unique IP
    determine if static address in range supported by
    or dynamic IP router.
    address in use. If dynamic IP address, make
     
      sure only one DHCP server is
      on network.
       
Slow transfer Wireless: Check the wireless Use Mixed mode only if you
speeds Network run- router/access point must support a mixture of
  ning in Mixed configuration. standards (802.11b + g, and
  mode.   so on).
      Upgrade devices to 802.11n if
      possible.


 

Wired: Switch Check signal lights

 

not running on the network

 

in full-duplex adapter or on the

 

mode. switch to verify the

 

mode in use.


Open the network adapter properties sheet and verify the full-duplex setting in use.


 

Wired: Mixture Check switch and

 

of slower and network adapters

 

faster network to determine the

 

hardware. speeds supported.


The network uses speeds of slowest devices.

 

If most devices on the net-work and switch use Gigabit Ethernet, upgrade the remain-der of devices.

 

Subdivide the network into Fast and Gigabit subnets.


      Chapter 9: Troubleshooting 185
       
       
Symptom Possible Items to Check Typical Solution
  Cause    
       
Low RF Signal Intermittent con- Check the signal Look for interference sources
  nectivity. strength (number near the router/access point or
    of bars) on devices between the router and access
    with the intermit- point.
    tent connection. If the adapter is external,
     
      move to a different position.
      If antennas are in the laptop
      screen, adjust the laptop
      screen position or move lap-
      top.
      Replace the wireless G adapt-
      er with a wireless N adapter.
       

 

Troubleshooting Operating Systems

 

The following section reviews common causes for problems with operating systems and typical solutions. Use the tools in Table 9-8 to find and solve problems with Windows XP, Windows Vista, and Windows 7.