I recently consulted on an MPLS-migration project. I have witnessed a large migration several years ago and was glad to see the improvements in the technology.
MPLS, or multi-protocol label switching, is a wide-area network service offering from telcos. Considering MPLS in the context of the OSI model, it operates kind of at layer 2.5 (Hey, Cisco said it, not me). It uses data-link layer MAC address technology but inserts labels in each packet which allow layer 2 devices to route to the correct destination. Thus the “label switching” part of the name. It is “multi-protocol” because it works with the multiple protocols of TCPIP and frame relay and ATM protocols which provides great flexibility when integrating legacy applications. It’s also designed with QoS (Quality of Service) technology which lends itself to latency-sensitive applications like VoIP and video. The MPLS product also allows for maximum flexibility in provisioning. An increase in bandwidth does not mean installation of a new circuit.
MPLS is a nice product, but it is expensive. For your Fortune 500 companies, it is a no-brainer. For this client I referenced, they are non-profit and getting some great discounts, but not everyone will have those options. I recently worked for a smaller company with about 70 locations. There was no way I could have sold MPLS service offering to business management. Broadband VPN was cheap and did the job just fine for limited data sharing which was really all the sites needed. For the typical IT manager at an SMB, the current MPLS offering is an excellent large-scale example of where you should choose technology that’s right for the particular organization over that which is just really cool. Unless your sites are tightly controlled from a headquarters location, run VOIP and video conferencing, the business case is just not there.