Address Cache-the Application of Hash Table

When routing switch forwarding IP packet,it will check its router table entries for best path to the destination.It's a time consuming processing to realize this function at network layer.With network scale grows,the router table expands much bigger and searching path in routing table becomes a bottleneck.Address cache can be used to speed up the routing process.This is done by routing first packet normally and forwarding subsequent packets directly using the route information found in first packet routing process.To realize this concept,an address cache is needed to caching the route information so that subsequent packets can be flown through the routing switch directly.