What Is MPLS?

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What is this new protocol that leading telecommunication experts claim “will take over the world”? You can rest your worried mind; Internet Protocol (IP) and asynchronous transfer mode (ATM) are not on the verge of extinction. In fact, it is my belief that multiprotocol label switching (MPLS) will breathe new life into the marriage of IP and ATM.

The best way to describe the function of MPLS is to draw an analogy to a large national firm with campuses located throughout the United States. Each campus has a central mail-processing point through which mail is sent, both around world and to other campuses. From the start, the mailroom has been under orders to send all intercampus correspondence via standard first-class mail. The cost of this postage is calculated into the company’s operational budget.

However, some departments have been complaining for several months that they require overnight delivery and package-tracking services. As a manager, you establish a system to send three levels of mail between campuses: first-class (normal) mail, priority (important) mail, and express mail (urgent). In order to offset the increased expense of the new services, you bill the departments that use these premium services at the regular rate of postage, plus 10 percent.

In this analogy, units of priority mail and express mail are processed by way of placement into specific envelopes with distinctive labels. These special labels and packets assure both prioritized handling and tracking capability within the postal network. In order to avoid slowdowns and bottlenecks, the postal facilities in the network create a system that uses sorting tables or sorting databases to identify and expedite these packets.

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