In the jargon of virtual private networks (VPNs), you may have heard the term MPLS. What is it, and what benefits does it provide?

What is MPLS?

MPLS stands for "Multiprotocol Label Switching." The important word is "label," which is what it uses to direct traffic. Internet-data packets typically make several hops from one router to another before reaching their final destination. All the routers know where the packet needs to end up, but each one makes its own decision about where it will go next.

If you've ever followed the online tracking of a post-office package, you've seen something similar. You bring the package to the local post office. It sends it to a central office, and from there it goes to another central office closer to the recipient. Then it's sent to a local post office, and finally it's delivered. You don't write on the package where it should go at each step.

Advantages of MPLS

With MPLS, a router creates a label that says exactly what path the packet should follow. This offers a couple of advantages. First, it saves subsequent routers the overhead of looking up the next destination. Second, it allows more detailed traffic control. An MPLS network can give certain types of traffic—such as real-time voice conversation—higher priority, making it easier to meet QoS requirements.

This doesn't mean MPLS depends on a rigid set of routers that never fail. The Fast Reroute feature provides a backup path at each point, in case the label's primary path is unavailable. This provides quick recovery from node failures.

An MPLS network with traffic-engineering support dynamically determines the best paths and updates its labels accordingly. The shortest path isn't always the fastest, and traffic engineering takes performance results into account.

If you're looking for more technical details, North American Network Operator's Group (NANOG) has a good introduction to MPLS.

For information about how MPLS VPN can help your business, contact TelWare at 1-800-637-3148 or TelWare is a national leader in the installation of voice, video, data and unified communication solutions. TelWare is an Authorized Avaya, Star2Star and SimpleWAN Dealer.

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