What ifIndex number should netflow stats appear on?

From: Martin_Nieuwelaar@infonet-europe.com
Date: Wed Feb 21 2001 - 06:21:31 PST

  • Next message: Pierre Vander Vorst: "Re: What ifIndex number should netflow stats appear on?"

    Hi people,

    We have recently started collecting Netflow Exports from a 12008 GSR in our
    network. It's running IOS 12.0(12)S. It has a POS interface 5/0 with
    ifIndex 10. There is a sub interface POS5/0.500 with ifIndex number 26.
    When I enable netflow exports, I find that cflowd gathers stats from the
    router with ifIndex number 25!!! (I expected them to have ifIndex number
    10). I looked up ifIndex number 25 using snmpwalk and I found
    POS5/0.500-cef layer. What gives? Are other poeple experiencing this too?

    This behaviour I have just mentioned differs from what I have become
    accustomed to. The other routers in the network behave as follows. These
    routers are 7500 series, running IOS 11. As an example a physical interface
    ATM4/0/0 has an ifIndex number of 16. A sub interface ATM4/0/0.211 exists
    but has no ifIndex number. Using snmpwalk I find there is an ATM4/0/0-atm
    layer (ifIndex number 40) and ATM4/0/0-aal5 layer (ifIndex number 41). The
    netflow stats that CFlowd receives all originate from ifIndex 16.

    So in summary the sub interfaces seem to be handled differently. Has anyone
    got a thought as to why there is a difference? Is it the IOS? Is that just
    how POS sub-interfaces work? Is there a document describing this? I know
    it's not specific to CFlowd, but I'm sure it's relevant to a lot of people
    here.

    Thanks in advance,

    -Martin 

    -- 
"Buying a car because it's reliable is like marrying
someone because they are punctual" - Jeremy Clarkson

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