I'm currently running flow-tools with snmp-server ifindex persist to calculate per- customer-interface-per-traffic-color (we've got several different traffic colors representing the type of traffic - local/national/international) usage.
ifIndexes are stored by ios in nvram:ifIndex-table and do really persist after reboot :) However, I've noticed all ifIndexes were incremented by 1 ( eg. 1 became 2, 10 became 11 and so forth) after IOS upgrade from 12.3(3a) to 12.3(9). Well .. cisco doesn't provide ifindex persistance after upgrade - only after reboot :-] I guess that was a one-time renumbering and that shouldn't happen again (12.3(9) to 12.3(10) upgrade haven't made any renumbering), but it should be kept in minds. Filtering by subnets is quiete hard to operate: one should track all customers' IP range changes and make appropriate modifications within its databases. One should also make himself sure no other IP ranges will be sourced from the customer's interface (yes I know about ip verify unicast source reachable-via rx - it's not applicable with asymetric routing). So I find my implementation to be the most acceptable for me :-) p.s. I was a little bit disappointed being unable to place a tag onto aggregated netflow : ( ---------- Original Message ----------- From: "Webb, Nathan" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]>, "Goran Sorak" <[EMAIL PROTECTED]>, <flow- [EMAIL PROTECTED]> Sent: Fri, 7 Jan 2005 09:43:54 +1100 Subject: RE: [Flow-tools] Changeable ifIndex > Another option is to filter on the IP subnets. If they have fixed ip > addresses, then this is probably going to be the easiest of all options. > > If the IP is dynamic, then provided that you retain logs of the IPs that > are allocated, you will be able to write a script that builds a filter > configuration file to extract flows for a certain IP address during the > times that the customer was connected. We're currently during this for > dial-up customers by extracting data from the radius logs. > > Bear in mind that if you have multiple exporters, then you will also > need to filter out all but the directly connected router, otherwise you > will get duplicate flows from other exporters by using this method. > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Geoffrey > Bradford > Sent: Friday, 7 January 2005 12:39 AM > To: 'Goran Sorak'; [email protected] > Subject: RE: [Flow-tools] Changeable ifIndex > > I create WAN reports from NetFlow that aggregate by the WAN interface. > In > my case I keep an intermediate mapping table of ifDescr -> ifIndex which > is > updated a couple of times a day from SNMP polling of the SNMP interfaces > table ifEntry. > > This has been adequate for us. > > There is a Cisco IOS command "snmp-server ifindex persist" which is > supposed > to keep indexes from changing, we investigated but never had a need to > implement. There is plenty of info about this command at the Cisco web > site. > > http://www.cisco.com/warp/public/477/SNMP/ifIndex_Persistence.html > > Geoff Bradford > Principal Consultant > International Network Services > > -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of Goran Sorak > Sent: Thursday, January 06, 2005 12:37 AM > To: [email protected] > Subject: [Flow-tools] Changeable ifIndex > > Can flow-tools deal with changeable ifIndex values associated with > customers? > > Explanation: We want to get per-customer flow statistics. Customers are > dynamically allocated ifIndex, but the ifAlias associated with the > customer > is fixed. Can we get per-customer based statistics if the only way to > identify customer is ifAlias value? (per-interface aggregations work on > ifIndex, so they are not valid for this case). > > (Probably not for this list, but: can cisco Flow collector deal with > this > case?) > > Thanks > > Goran > _______________________________________________ Flow-tools mailing list [EMAIL PROTECTED] http://mailman.splintered.net/mailman/listinfo/flow-tools
