Patent ID: 7792047

Claim:
A packet switch configured to be connected to a packet-switching network and a network instrument, the packet switch comprising: a plurality of ports comprising a first port, a second port, and a third port, wherein the first port is configured as a first network port to be connected to the packet-switching network; a plurality of filters, wherein one of the filters is associated with one of the ports, and wherein the filters only filter packets entering through the ports; and a computer-readable medium containing computer-executable instructions to operate the packet switch, comprising instructions to: configure the second port to operate as a first instrument port to be connected to a network instrument; establish a logical connection between the first network port and the first instrument port; forward packets received from the packet-switching network through the first network port to the first instrument port; after the packets are forwarded from the first network port, filter the packets using one of the filters before sending the packets out the first instrument port; and configure the third port on the packet switch to operate as a first loop-back port, wherein a packet sent out the first loop-back port is looped back in through the first loop-back port, wherein the logical connection established between the first network port and the first instrument port includes a logical connection established from the first network port to the first loop-back port, and a logical connection established from the first loop-back port to the first instrument port, and wherein the packets forwarded from the first network port are forwarded from the first network port to the first loop-back port, and are forwarded from the first loop-back port to the first instrument port; and establish a first filtering criterion for a first filter associated with the first loop-back port, wherein the packets are filtered by filtering the packets using the first filter associated with the first loop-back port based on the first established filtering criterion before the received packets are forwarded from the first loop-back port to the first instrument port.