On 03/03/2011 09:30, Florian Weimer wrote:
With IPv4, you can aggregate routes before installing them into the FIB (because only few of the routing decisions are semantically meaningful), at least if the CPU which computes the FIB is a bit more beefy than what is built into your smartphone. If your vendor still isn't doing that, it might make sense to consider switching vendors, or at least use it as a negotiating tool for getting better deals on upgrades.
You can certainly do this with lookup engines. Problem is that if you do it, you're breaking the deterministic rib->fib relationship model and replacing it with a nondeterministic system, which will probably work very well in almost all situations, but which has corner cases which fail catastrophically once you run out of lookup engine bits. Looking at it another way, automatic route aggregation creates overcommit between the RIB and the FIB. If that overcommit charge is exercised, things will break horribly. Nick