Method to Measure Packet Processing Time of Internet Hosts with Specialized Packet-Capture Line Card

The packet processing time (PPT) of a host is the time elapsed between the arrival of a packet at the data-link layer and the time the packet is processed at the application layer of the TCP/IP protocol stack. To measure the PPT of a host, stamping the times when these two events occur is needed. However, popular network interface cards (NICs) do not provide such time stamping facility. The use of a packet-capture line card (PCL) may be considered, but the clocks of the PCL and the host under measurement may need to be synchronized, and this is complex as the clock of the host’s operating system runs at lower speed than that of the PCL and the PCL may be unable to forward packets to the application layer on real time. In this letter, we propose a scheme to measure the PPT of a host using the Internet Control Message Protocol (ICMP) echo request and reply packets, and a PCL in the same network segment. The proposed scheme does not require clock synchronization between the host under measurement and the PCL. We tested the scheme on different hosts under different transmission speeds, using integrated and extended NICs.