Multiple Network Adapters

[Rob T]

I have a customer with a laptop that has both wired and wireless networking.
She has trouble understanding how to turn one off and the other on when
moving to different environmens (e.g. home, away etc.) My question is, what
is the net effect if she leaves both active (i.e. will she get the benefit of
the 100mbps of the wired NIC, the 54mbps of the wireless one, both or some
reduced speed due to the two connections fighting)?

 

[GTS]

She can leave them both on. XP will use the wired one if both connections
are available. (It is possible to change that by setting a metric, but this
is usually what you want.) If there is no wired connection available and
she connects to a wireless access point it will simply use that one.

 

[Jack \(MVP-Networking\).]

Hi
Configure the TCP/IP metrics to prefer the Wire connection.
When the wire is unplugged and there is Wireless available it would kick in.
Here how,
Jack (MS, MVP-Networking)

 

[Rob T]

Could you tell me how to do that? I looked in the TCP/IP properties of both
the wired and wireless connection, but I didn't find anything that I could
recognize as "metrics". I'm not expert in that area, so any help you could
give me would be greately appreciated.

 

[James Egan]

I have a customer with a laptop that has both wired and wireless networking.
She has trouble understanding how to turn one off and the other on when
moving to different environmens (e.g. home, away etc.) My question is, what
is the net effect if she leaves both active (i.e. will she get the benefit of
the 100mbps of the wired NIC, the 54mbps of the wireless one, both or some
reduced speed due to the two connections fighting)?

It is not satisfactory to leave them both enabled. They will indeed
conflict at some point since the computer will expect the same
conditions when it is started up as the last time it was closed down
and it won't always get them. You need to create hardware profiles to
overcome this.

In one hardware profile enable the wireless adaptor and disable the
wired. In the other, enable the wired and disable the wireless. Then
when you boot up the machine you will get an extra menu before going
into windows asking whether you want the wired profile or the wireless
profile.

http://support.microsoft.com/kb/308577


Jim.

 

[James Egan]

Configure the TCP/IP metrics to prefer the Wire connection.
When the wire is unplugged and there is Wireless available it would kick in.

Although a lower metric would give preference to the wired connection
there is absolutely no benefit at all in having both adaptors enabled.

The switch from wired to wireless (on being uplugged) would not be
instantaneous and of course assumes that tcp/ip will be the only
protocol used. Although that is a major probability it is not a
certainty.

Here how,

You missed a bit


Jim.

 

[GTS]

The setting is accessed via the Advance button on the General tab of the
TCP/IP properties / IP settings tab of the advanced window. However, there
is no need for you to manually set this. The automatic metric assignment in
XP generally works fine in this situation. XP automatically configures the
TCP/IP metrics to prefer the Wire connection.

When a laptop has an available wired and wireless connection available at
start up, it will route through the wired one. If you plug in a wired
connection later, it will not automatically change to it. That's one of
the few situations where manual action may be appropriate (disabling the
wireless connection) in order to force a change if you want to. There are
sometimes issues after standby or hibernate as well, but for routine day to
day operations, XP handles things quite well automatically. There is
neither a benefit nor an adverse effect on speed by having both active.

See An explanation of the Automatic Metric feature for Internet Protocol
routes
http://support.microsoft.com/kb/299540
and
What is Windows XP's automatic metric feature?
http://windowsitpro.com/article/articleid/27315/what-is-windows-xps-automatic-metric-feature.html

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