Re: performance metrics for IPS systems?

From: Mike Frantzen (
Date: 01/09/05

  • Next message: Ofer Shezaf: "RE: Specification-based Anomaly Detection"
    Date: Sun, 9 Jan 2005 08:49:51 -0500
    To: p z <>

    > I'm planning on demanding that the IPS systems perform at >225,000
    > packets/second (100% of packets inspected) with <.5ms latency per
    > packet. Is this reasonable for an IPS?

    Just be careful how you measure that .5ms latency limit. If you do a
    single ping without background traffic against an IPS that does
    interrupt polling then you'll see latency of about 1ms or 10ms
    (depending on the underlying operating system used). That latency
    will start to drop once you have over 1000pps and will gradually
    converge towards zero.

    I'm not sure which IPS vendors do interrupt polling to gain performance.
    It wasn't worth it for us.

    > - What is the acceptable/standard latency per packet for an IPS?

    Humans begin to notice latency at about the 200ms mark (call it 100ms to
    account for the return packet). TCP behavior changes at 30-100ms unless
    the stack does round trip time measurements. Online gamers get cranky
    at the 80-100ms mark.

    That being said, you probably won't find an IPS that introduces more than
    1ms of latency.

    frantzen@( | |
    PGP: CC A4 E2 E8 0C F8 42 F0 BC 26 85 5B 6F 9E ED 28

    Test Your IDS

    Is your IDS deployed correctly?
    Find out quickly and easily by testing it with real-world attacks from
    Go to
    to learn more.

  • Next message: Ofer Shezaf: "RE: Specification-based Anomaly Detection"