System for communicating heterogeneous computers that are coupled through an i/o interconnection subsystem and have distinct network addresses, via a single network interface card

Abstract

A first network protocol provider, executing on a first computer system and having a first network address associated therewith, and a second network protocol provider, executing on a second computer system and having a second network address associated therewith, share a same network interface card installed on the second computer system. Apparatus providing this ability comprises an interconnection between the first and second computer systems over which data can be transferred between them, and a router executing on the second computer system that routes data among the first network protocol provider (via the interconnection), the second network protocol provider, and the network interface card in a manner that enables the network interface card to be shared between the first and second network protocol providers. For example, when data is received from the network by the network interface card, the router routes the data to the first network protocol provider, via the interconnection, when a network address received with the data matches the first network address, but passes the received data to the second network protocol provider when the network address received with the data matches the second network address. A “loopback” capability also allows data addressed from one network protocol provider to the other to be transmitted between them directly (via the interconnection), bypassing the network interface card. The router can also handle broadcast addresses.