Patent ID: 7418732

Claim:
A local area computer network comprising: a plurality of computers; and at least one network switch comprising: a plurality of ports, each port being directly connected to a respective one of the plurality of computers of the local area computer network; a switching control programmed to route packets between the ports; and a virus scanner programmed to scan the packets for viruses for determining, from among the plurality of computers, a source computer of a virus, the determination being carried out by detecting the virus in packets received through a first port among the plurality of ports and using the first port to identify the source computer that is directly connected to the first ports, the virus scanner performing scanning in an off-line mode such that scanning is performed in parallel with the routing of packets by the switching control, the off-line scanning and the routing comprising: receiving each packet from a device at a source port; storing a copy of the received packet in a queue of un-scanned packets and also forwarding the received packet to a destination port thereof without waiting for the virus scanner to complete scanning the copied packet in the queue; the virus scanner processing each packet in the queue on a first-in-first-out (FIFO) basis such that the oldest packet in the queue is processed first; and determining that incoming packets are arriving at the switch at a rate faster than the virus scanner can scan the incoming packets, and in response to so determining, writing each incoming packet over an oldest unprocessed packet in the queue such that at least some packets in the queue are discarded without being scanned.