multihome processing
The following is a summary of the network traffic behavior when a computer running Windows XP or Windows Server 2003 is connected to both a wired and wireless network (hereafter referred to as a multihomed computer):
(
MS KB article here)
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For traffic initiated by other computers that are neighbors of the multihomed computer, the traffic flows over the network adapter attached to the common subnet. For example, if a neighboring computer on the Ethernet-based subnet of the multihomed computer initiates traffic, the traffic flows over the Ethernet network adapter.
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For traffic initiated by other remote computers (located beyond the locally attached subnets), the traffic flows over the network adapter corresponding to the destination IP address chosen by the initiating computer. For example, a multihomed Windows XP-based computer will register the IP addresses for both wired and wireless network adapters in the Domain Name System (DNS) using DNS dynamic update. When another computer queries for the name of the multihomed computer, it will get both of the multihomed computer's IP addresses in random order. The DNS client resolver in Windows XP chooses the first IP address in the list returned by the DNS server.
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For traffic initiated by the multihomed computer for neighboring destinations, the traffic flows over the network adapter attached to the common subnet. For example, if a neighboring computer is on the Ethernet-based subnet of the multihomed computer, the traffic flows over the Ethernet network adapter.
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For traffic initiated by the multihomed computer for remote destinations, the
traffic flows over the network adapter associated with the currently chosen default route in the IP routing table, unless there are additional routes to the remote destination.
Assuming that the multihomed computer is running mostly client applications and accessing servers on remote subnets, most of the traffic of the multihomed computer is in the last category (traffic initiated by the multihomed computer for remote destinations).