Overview

The Internet has long provided fertile ground for technological innovation. As new networking technologies spring up, some manage to attract a remarkable level of attention. Multiprotocol label switching MPLS is one such technology. This book provides a thorough and balanced examination of MPLS and aims to answer some fundamental questions about the technology. First, what is MPLS? Second, how does it work? And finally, what benefits does it provide? In answering this last question, we hope to show that the benefits offered by MPLS justify the attention it has received in the networking industry.

MPLS evolved from several similar technologies that were invented in the mid-1990s. The most well known of these (although not the first to be publicly disclosed) was dubbed IP Switching by its inventors at the start-up company Ipsilon. Toshiba had previously described a similar scheme, implemented in their Cell Switching Router (CSR), and several other approaches were soon published, notably Cisco s Tag Switching and IBM s Aggregate Route-based IP Switching (ARIS). All of these approaches share some common traits. They all use a simple label swapping technique for forwarding data. They all use the control paradigm of the Internet protocol suite. That is, they use IP addresses and standard Internet routing protocols such as OSPF and BGP. However, the various approaches differ significantly in their goals as well as in the details of their implementation.

With all this activity, it was not too surprising that the Internet Engineering Task Force (IETF) chartered a...