Re: netflow is correct but interface counters lie?!

From: Dylan Hall (dylan.hall@tsnz.net)
Date: Wed Feb 28 2001 - 12:32:48 PST

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    Does the PPP session use Van Jacobson header compression? This would
    cause the header to vary in size.

    Lars Michael Jogback wrote:
    >
    > > This is 4 bytes to much. I encounter this +4 bytes with UDP packets, too.
    > > Does it measure HDLC, too? Can I get the raw IP Counter with snmp?
    >
    > According to this Cisco FAQ the answer to your first question is yes,
    > ifInOctets contains HDLC (or PPP) header.
    >
    > http://www.cisco.com/warp/public/477/SNMP/snmp_faq.html#11
    >
    > > Strangely this +4 rule cannot applied everytimes. Especially with TCP data
    > > I have varying values, even different delta values for input and output.
    >
    > This sounds really strange...
    >
    > /LM
    >
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    > cflowd@caida.org

    -- 
    Dylan Hall
    IP Engineer
    TelstraSaturn Ltd
    Ph: +64 4 9228400 Fax: +64 4 9228401
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