Latency measurment apparatus and method

A method of measuring latency through a device includes the steps of:

• generating a packet for transfer to the device, the packet having a sequence number associated therewith;
• forwarding the packet number to a first network interface;
• forwarding the packet from the first network interface via time stamp generation logic which generates a transmit time stamp for the packet, the transmit time stamp reflecting the time at which the packet is forwarded from the first network interface to the device;
• and
• inserting the transmit time stamp into the packet prior to forwarding to the device.

An apparatus for measuring the latency of a device includes:

• means for generating a packet to transmit to the device, the packet having a sequence number associated therewith;
• a first network interface card for transmitting the packet to the device;
• transmit time stamp means, coupled to the first network interface card, for capturing a transmit time stamp for the packet, the time stamp reflecting the time the packet is transmitted from the first network interface card;
• a queue for storing descriptor information for each packet transmitted from the first network interface, the information including the transmit time stamp and the sequence number.

An apparatus for measuring the latency of a device includes:

• means for generating a packet to transmit to the device, the packet having a sequence number associated therewith;
• a network interface card for transmitting the packet to the device;
• and
• transmit time stamp means disposed between the network interface card and the device, for capturing a transmit time stamp for the packet and inserting the transmit time stamp into the packet, the time stamp reflecting the time the packet is transmitted from the first network interface card.