Does Windows 7 support 802.3ad (link aggregation) natively?

For NIC teaming or link aggregation support, you'll need to contact your network adaptor vendor or OEM (e.g. Dell offers a teaming driver). They will need to provide you a driver that enables NIC teaming, since Windows does not offer this functionality in the core OS.

Source: http://answers.microsoft.com/en-us/windows/forum/windows_other-networking/does-windows-natively-support-link-aggregation/81e647f9-d89e-4028-8370-7e8bb0e3dc2f?msgId=6ca73c70-5ea7-4054-a75a-1be66d545b8a