Andre: #2 FIBs doesn't have to be impacted by Moore's law. In certain times of routing technology people "cooked" routing tables in order to solve #2. The key there is to run through the proposed FIB table Generated by a routing table and cook it for FIB insertion. You can often summarize (from the viewpoint of a particular router) all the routes into a manageable set of FIB entries. The issue is how much fluctuation. 10% (actually 8-14% but 10% is average) of the Internet (see route-views, etc). FIB hardware can allow you to split the prefix load and the next-hops. So, you load prefixes that fluctuate and only break the prefix-next-hop when they fluctuate. .. bottom line.. I don't think we will be limited by Moore's law for #2.. If we utilize existing technology existing in Hw and software methodology, we can change the game on #2. Sue Hares PS - My answers tend to be brief - glad to expand in private or public. Your choice. -----Original Message----- From: owner-nanog@merit.edu [mailto:owner-nanog@merit.edu] On Behalf Of Andre Oppermann Sent: Tuesday, October 18, 2005 11:31 AM To: nanog@nanog.org Subject: Scalability issues in the Internet routing system I guess it's time to have a look at the actual scalability issues we face in the Internet routing system. Maybe the area of action becomes a bit more clear with such an assessment. In the current Internet routing system we face two distinctive scalability issues: 1. The number of prefixes*paths in the routing table and interdomain routing system (BGP) This problem scales with the number of prefixes and available paths to a particlar router/network in addition to constant churn in the reachablility state. The required capacity for a routers control plane is: capacity = prefix * path * churnfactor / second I think it is safe, even with projected AS and IP uptake, to assume Moore's law can cope with this. 2. The number of longest match prefixes in the forwarding table This problem scales with the number of prefixes and the number of packets per second the router has to process under full or expected load. The required capacity for a routers forwarding plane is: capacity = prefixes * packets / second This one is much harder to cope with as the number of prefixes and the link speeds are rising. Thus the problem is multiplicative to quadratic. Here I think Moore's law doesn't cope with the increase in projected growth in longest prefix match prefixes and link speed. Doing longest prefix matches in hardware is relatively complex. Even more so for the additional bits in IPv6. Doing perfect matches in hardware is much easier though... -- Andre