With the proliferation of Web and multimedia services, and virtual private networks (VPNs) connecting corporate sites, more versatile Internet routing protocols have become critical. Current Internet packet forwarding is based on the destination address. Simple routing algorithms that determine forwarding paths based on the minimum number of hops or delay to a specified destination are no longer sufficient. The need to support diverse traffic types and applications with quality demands (see Figure 1) imposes new requirements on routing in the (now commercial) Internet. New routing paradigms are also required to handle service agreements among service providers and users. Administrative policies, performance requirements, load balancing, and scalability are thus becoming increasingly significant factors in Internet.
