Means for allowing two or more network interface controller cards to appear as one card to an operating system

摘要

The present invention provides a method and an apparatus for allowing a plurality of network interface controllers (NICs) to appear as a single NIC to an operating system. This method and apparatus is realized externally to the NIC driver software, and thus does not require NIC drivers to be modified. The present invention also operates independently of operating system, NIC driver software, NIC drivers and NIC hardware. Consequently, the present invention is compatible with a wide range of operating systems and NICs. One embodiment of the present invention operates at the MAC level and lower, thus avoiding the complexity of providing software support for higher layer protocols. However, providing support at the MAC level and lower makes it difficult to perform inbound load sharing. This is because protocols such as IPX use addresses and packet headers to direct reply packets. Hence, return traffic is directed back to the originating NIC regardless of whether the originating NIC is heavy loaded or not. However, 60% to 80% of all traffic on a server is outbound because workstations typically read files from a server in a direction that is outbound from the server. Hence, load sharing for outbound traffic will significantly improve overall system performance even if it is not possible for inbound traffic.