Evolution on the network edge: intelligent devices

A network's edge is arguably one of its most important areas, because this is where it delivers services to network users-or, from the Internet service provider perspective, to subscribers. Devices at the network's edge classify, prioritize, and mark packets for the rest of the network to understand, and ultimately allow them into the network. Given modern networks' complex internetworking, it is not surprising that developing and maintaining edge devices are tasks that head the agendas of most of today's network equipment manufacturers, carriers, service providers, and network administrators. This article examines key elements of current network edge devices and the network topologies that work best with them. It also discusses Multiprotocol Label Switching (MPLS), a standardized solution that combines the performance and virtual circuit capabilities of data-link-layer switching with the proven scalability of network layer routing used by today's edge devices.