Prioritize Network cards

  • Thread starter Thread starter BGZ
  • Start date Start date
B

BGZ

This seems to be a simple problem but I can't seem to find
the answer anywhere; I have a number of laptop users in my
building who have integrated wireless cards and who want
to use them when they are in our "hotspots" (conference
rooms, training room, etc). They would go wireless the
whole time but the signal is too inconsistant in most of
the office areas to be of substantial value. The problem
with this is that when the users log into the network
wired, network access is EXTREMELY slow untill I disable
the wireless NIC. Is there a way to prioritize the NIC's
so that the wireless does not connect untill a wired
connection is not present?
 
I'm assuming you're running DHCP on your infrastructure, and I'll venture to guess that you've fired up your wireless nic AFTER your wired connection has already grabbed it's DHCP assignment. What is happening here is that the last card to get a DHCP assignment becomes the default adapter. I usually do this in reverse; when I'm streaming something over my wireless NIC, and I want to get more bandwidth (so the Linksys Wireless AP router doesn't have to reconstruct the packets, as wireless packets are larger than standard ethernet packets), I simply connect the wired NIC to it. After it sends out a DHCP request and receives its assignment, Windows automatically shifts the stream (quite seamlessly, I might add) over to the other card, and after that I just shut down the wireless card. Just a question - are these integrated MiniPCI cards? If they are, there should be a hotkey to turn the antenna on and off (mine is Fn+F2 (Dell Inspiron 8500)). If these are external cards, don't pop the card into the slot when you boot; do it right when you want to go wireless. Other than that, I don't know of any setting where you can keep one NIC from automatically becoming the default adapter. Hope this helps.
 
I'm assuming you're running DHCP on your infrastructure, and I'll
venture to guess that you've fired up your wireless nic AFTER your
wired connection has already grabbed it's DHCP assignment. What
is happening here is that the last card to get a DHCP assignment
becomes the default adapter.
Click to expand...

That looks like how it works in many cases, but it really isn't. The
order in which network adapters get their DHCP assignments doesn't
determine their priority on the network. More information below.
I usually do this in reverse; when I'm streaming something over my
wireless NIC, and I want to get more bandwidth (so the Linksys
Wireless AP router doesn't have to reconstruct the packets, as
wireless packets are larger than standard ethernet packets), I simply
connect the wired NIC to it. After it sends out a DHCP request and
receives its assignment, Windows automatically shifts the stream
(quite seamlessly, I might add) over to the other card, and after that
I just shut down the wireless card.
Click to expand...

Yes, that's exactly how it should work, but it's not because the wired
card is connected after the wireless card. More information below.
Just a question - are these integrated MiniPCI cards? If they are,
there should be a hotkey to turn the antenna on and off (mine is Fn+F2
(Dell Inspiron 8500)). If these are external cards, don't pop
the card into the slot when you boot; do it right when you want to go
wireless. Other than that, I don't know of any setting where you can
keep one NIC from automatically becoming the default adapter.
Hope this helps.
Click to expand...

When more than one network adapter connects to the same network,
Windows looks at the "metric" value assigned to each adapter, and it
uses the network adapter with the lowest metric value.

Windows XP automatically computes a metric for each adapter, based on
the rated speed of the adapter: the higher the rated speed, the lower
the metric that it computes. So, for example, a 100Mb wired adapter
gets a lower metric (higher priority) than an 11Mb 802.11b wireless
adapter. This Microsoft Knowledge Base article has details:

An Explanation of the Automatic Metric Feature for Internet Protocol
Routes
http://support.microsoft.com/?id=299540

Based on the information in that article, a 54Mb 802.11g wireless
adapter would get the same metric value (20) as a 100Mb wired adapter.
In a case like that, where the automatic metrics don't work correctly,
you can manually assign a metric to each network adapter:

1. Open the Network Connections folder.
2. Right click the network connection that uses the adapter.
3. Click Properties | Internet Protocol (TCP/IP).
4. Click Properties | Advanced.
5. Un-check "Automatic metric".
6. Enter a number between 1 and 9999 for the "Interface metric".
--
Best Wishes,
Steve Winograd, MS-MVP (Windows Networking)

Please post any reply as a follow-up message in the news group
for everyone to see. I'm sorry, but I don't answer questions
addressed directly to me in E-mail or news groups.

Microsoft Most Valuable Professional Program
http://mvp.support.microsoft.com
 
Back
Top