I am with an ISP that is trying to migrate 4000 plus DSL subscribers to a 6509 platform, and leave room for some expansion (say 3000 more subscribers) when we setup a 6509 with SUP720's, WS-X6582-2PA, and Enhanced OC3 Port adapter cards, we are only allowed 5000 IDB's on the system for interfaces and sub-interfaces, which will cover our current load, but not leave room for future expansion. I see in some of the forums people with similar setups are reaching 15000 and higher IDB's. what is the limiting factor in IDB's on this platform? I am running IOS 12.2.18 SXF10a Advanced IP services. All this router will be doing is ATM aggregaion, nothing fancy.
I have this problem too.