US Patent 7693045 Verifying network connectivity

A system comprising a computer including a plurality of network interface controllers (NICs), the plurality of NICs associated with an address. The system further comprises a switching apparatus coupled to the computer and an echo device coupled to the switching apparatus. The echo device is adapted to send a packet to the switching apparatus to verify connectivity with the plurality of NICs. The packet comprises the address. The switching apparatus compares the address with a data structure to locate a matching address. If no matching address is located, the switching apparatus sends copies of the packet to each of the plurality of NICs coupled to the switching apparatus.