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GeneralRe: Processor Difference Pin
Cmania23-Jan-08 0:59
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GeneralDriver Installation/Uninstallation Pin
pvn g7-Jan-08 0:57
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GeneralRe: Driver Installation/Uninstallation Pin
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GeneralRe: Driver Installation/Uninstallation Pin
fat_boy18-Jan-08 3:47
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GeneralRe: Driver Installation/Uninstallation Pin
Dan Neely18-Jan-08 3:53
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GeneralRe: Driver Installation/Uninstallation Pin
fat_boy18-Jan-08 3:58
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QuestionLAN - wired and wireless selection Pin
Vaclav_3-Jan-08 17:33
Vaclav_3-Jan-08 17:33 
GeneralRe: LAN - wired and wireless selection Pin
Mike Dimmick6-Jan-08 1:48
Mike Dimmick6-Jan-08 1:48 
Vaclav_Sal wrote:
How does OS determine which network adapter to use?


If you have multiple network adapters connected, the system is multi-homed. The decision as to which route packets take is dependent on:

1. The routing table.
2. The 'weight' given to each network interface.

Strictly the weight is part of the routing table, but takes effect only if identical routes are discovered.

The IP routing table can be made incredibly complex, but for most systems not otherwise configured, you basically get a default route (to 0.0.0.0 masked 0.0.0.0, i.e. anywhere) configured to use your default gateway via each interface, with a weight. The wired network card will typically get given a lower weight and be preferred to the wireless card. Likewise each card will have a route for the IP and mask it's configured for. If the cards are on the same network, again the wired card will be preferred.

If the cards are on different networks (IP ranges), packets for the wired card's network should go to the wired card and vice versa. Packets for other networks will go to whichever card the default gateway is nearest to. If there are multiple 'default gateways' the weight again controls which is used.

The routes for the wired card will be (or should be) removed if the OS detects that the cable has been unplugged. Only then will the wireless card be used.

You can view the routing table by issuing the route print command.

Example: I have a wired network card and a wireless card. I'm running Windows Vista. My IPv4 routing table is, with both enabled and in good coverage:
Network Destination        Netmask          Gateway       Interface  Metric
          0.0.0.0          0.0.0.0      192.168.1.1      192.168.1.2     20
          0.0.0.0          0.0.0.0      192.168.1.1      192.168.1.4     25
        127.0.0.0        255.0.0.0         On-link         127.0.0.1    306
        127.0.0.1  255.255.255.255         On-link         127.0.0.1    306
  127.255.255.255  255.255.255.255         On-link         127.0.0.1    306
      192.168.1.0    255.255.255.0         On-link       192.168.1.2    276
      192.168.1.0    255.255.255.0         On-link       192.168.1.4    281
      192.168.1.2  255.255.255.255         On-link       192.168.1.2    276
      192.168.1.4  255.255.255.255         On-link       192.168.1.4    281
    192.168.1.255  255.255.255.255         On-link       192.168.1.2    276
    192.168.1.255  255.255.255.255         On-link       192.168.1.4    281
        224.0.0.0        240.0.0.0         On-link         127.0.0.1    306
        224.0.0.0        240.0.0.0         On-link       192.168.1.2    276
        224.0.0.0        240.0.0.0         On-link       192.168.1.4    281
  255.255.255.255  255.255.255.255         On-link         127.0.0.1    306
  255.255.255.255  255.255.255.255         On-link       192.168.1.2    276
  255.255.255.255  255.255.255.255         On-link       192.168.1.4    281
The wired card has address 192.168.1.2 while the wireless card is 192.168.1.4. You can see I have two routes for the 192.168.1.x network, with the wired card having weight 276 compared to wireless 281, so the wired card is preferred. Multicast is on 224.x.x.x and again wired is preferred to wireless and loopback (weight 306). Broadcasts (all-ones and 192.168.1.255) are all weighted to wired as well. Packets addressed to the loopback network (127.0.0.0) all go to the loopback interface. Finally, there are the two default routes and both state to send to 192.168.1.1, but again the wired network takes priority.

Why does the "status" of wireless show "cable unplugged" at times?


Most likely you're out of range or on the borders of coverage. Windows 2000 does not understand wireless cards, so the card reports poor network performance as 'cable unplugged', so that the OS can make better routing decisions. If you care, get an OS (e.g. XP SP2) which understands wireless cards.

Vaclav_Sal wrote:
It seems that the LAN device cannot be enabled / disabled in Control Panel with any confidence. It is a hit and wait and try again affair.


I've not seen this behaviour, but it can take a while for wireless devices to associate with a network. They are also supposed to disassociate from the base station when being disabled, which should be acknowledged, which could take a while to time out if out of coverage.


DoEvents: Generating unexpected recursion since 1991

GeneralRe: LAN - wired and wireless selection Pin
fat_boy18-Jan-08 3:57
fat_boy18-Jan-08 3:57 
General80GB HDDD display 32 GB Capacity Pin
Sachin Pimpale27-Dec-07 20:49
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GeneralRe: 80GB HDDD display 32 GB Capacity Pin
Dave Kreskowiak27-Dec-07 21:29
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GeneralRe: 80GB HDDD display 32 GB Capacity Pin
Sachin Pimpale27-Dec-07 21:36
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GeneralRe: 80GB HDDD display 32 GB Capacity Pin
Mike Dimmick28-Dec-07 9:50
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QuestionRecover data from a replaced partition. Pin
mejax22-Dec-07 1:04
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GeneralRe: Recover data from a replaced partition. Pin
Johpoke24-Dec-07 10:25
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GeneralRe: Recover data from a replaced partition. Pin
Dave Kreskowiak24-Dec-07 18:54
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GeneralRe: Recover data from a replaced partition. Pin
Dan Neely2-Jan-08 10:59
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GeneralContact/Contactless Module Test Pin
codeadair19-Dec-07 15:30
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Generalmy computer HALTS sometimes, sometimes not... Pin
anthoy18-Dec-07 20:55
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GeneralRe: my computer HALTS sometimes, sometimes not... Pin
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GeneralRe: my computer HALTS sometimes, sometimes not... Pin
anthoy19-Dec-07 0:03
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GeneralRe: my computer HALTS sometimes, sometimes not... Pin
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GeneralRe: my computer HALTS sometimes, sometimes not... Pin
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GeneralRe: my computer HALTS sometimes, sometimes not... Pin
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GeneralWindbg remotely also posted under OS/ SYsadmin Pin
ForNow12-Dec-07 22:06
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