Several network adapters

Discussion in 'Windows XP Networking' started by Guest, Aug 8, 2006.

  1. Guest

    Guest Guest

    What rules are there that decides which network adapter (assuming I have
    several network adapters on my PC) network information uses to send
    information on a Windows XP Pro PC?
     
    Guest, Aug 8, 2006
    #1
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  2. I assume that the computer uses the TCP/IP protocol on the network.

    Windows XP creates a network connection for each installed network
    adapter. It decides which connection to use by looking up the
    destination IP address in the TCP/IP route table, which defines the
    range of IP addresses that each connection can access.

    When multiple connections can access the same destination, XP uses the
    connection with the lowest metric value. By default, XP assigns a
    metric value based on the rated speed of a connection:

    An explanation of the Automatic Metric feature for Internet Protocol
    routes
    http://support.microsoft.com/Default.aspx?id=299540

    If automatic metrics don't do what you want, you can assign them
    manually. To assign a metric to a network connection:

    1. Open the Network Connections folder.
    2. Right click the desired connection.
    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
     
    Steve Winograd [MVP], Aug 8, 2006
    #2
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  3. Guest

    Guest Guest

    On the local network the binding-order determines this.

    Over longer distances the number of 'hops' (routing cost) for each route may
    come into play.
     
    Guest, Aug 8, 2006
    #3
  4. What do you mean by "binding-order", Ian, and how do you configure it?

    If you mean the order in which connections appear in the Connections
    window of Network Connections > Advanced > Advanced Settings >
    Adapters and Bindings, then I disagree. If you mean something else,
    please describe it.

    For the TCP/IP protocol, Windows XP looks at the route table to
    determine which connection(s) can reach a destination IP address.
    When more than one connection is possible, XP looks at the metrics for
    the connections and uses the one with the lower metric. Even if the
    metrics are equal, the binding order has no effect on LAN use in my
    tests, both for pings and for accessing shared folders.

    This behavior is the same for all networks. Windows XP doesn't
    distinguish between LANs, WANs, etc.
    I don't know of any way that Windows XP computes or uses the number of
    'hops' to a destination. If you do, please describe it. Routing
    choices are based on metrics. XP computes metrics based on connection
    speeds.
    --
    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
     
    Steve Winograd [MVP], Aug 8, 2006
    #4
  5. Guest

    Guest Guest

    Thank you Steve,

    Lets say I set a lower metric on one adapter and a higher one on another.
    Will then an application try the adapter with the higher metric if it cannot
    find a host using the adapter with the lower metric?

    Best Regards,
    Joachim
     
    Guest, Aug 9, 2006
    #5
  6. No, it won't. If the adapter with the lower metric can't contact the
    host, the connection attempt will fail.

    If you always want to use a specific adapter to contact a specific
    host, you can specify a persistent route to that host. For example,
    if the host's address is 192.168.123.100 and the desired adapter is
    192.168.123.2:

    route -p add 192.168.123.100 mask 255.255.255.255 192.168.123.2
    You're welcome, Joachim.
    --
    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
     
    Steve Winograd [MVP], Aug 9, 2006
    #6
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