The large and constantly growing Internet routing table size is a longstanding problem that leads to increased convergence time, increased boot time, and costly equipment upgrades. The problem exists for both VPN and
global routing tables, and there is concern that IPv4 address space exhaustion over the next few years may lead to an increasingly fragmented address space, poor aggregation, and therefore a increase in the rate of routing table size. To address these issues, the IETF is working hard on new protocols that will shrink routing tables. In this talk, we present a way to shrink routing tables, easily by an order of magnitude or more, without any new protocols. The idea behind our approach, called Virtual Aggregation, is to partition the address space into large Virtual Prefixes, each of which is delegated to a tunneled virtual network composed of a fraction of ISP routers. Virtual Aggregation can be used independently by a single ISP, or cooperatively among a group of ISPs. This talk describes how Virtual
Aggregation can be configured and deployed, and gives performance results based on measurements made at a Tier-I ISP.