As computer networks, specifically the Internet, become more and more integral to business and society, the performance and availability of services on the Internet become more critical. It is now a common need to provide a reliable network service to millions of Internet users and customers. The performance of these services is commonly a key factor in their success. Web portals and popular sites build relationships with customers based in part on their speed and availability. Even services internal to an enterprise frequently have serious consequences if there is a loss of availability. This chapter discusses how advanced, multilayer switches can be used to increase the performance of network services. For this discussion, the term “performance” refers to availability, latency, and throughput, since all of these factors affect a user’s impression of a site’s performance. This chapter is intended for network service providers who must scale their services, network administrators who need to apply policies to their networks, and developers of switches who need to understand what the utility and requirements for these switches are. It is assumed that the reader has a working familiarity with networking principles, but substantial background information is also provided.