Three precautions

Anyone in the market ought to consider at least these three simple precautions when MPLS is in play:

1. Ensure that responsibility for network traffic labeling is assigned. This means more than watching as the carrier's sales rep nods and says it's handled. Just as access control lists between internal VLANs are necessary for meaningful segmentation, someone needs to define label assignment and distribution rules before data is forked over to the MPLS cloud.

2. The contract or service-level agreement should include a description of suitability, not just performance metrics for the connection. This means the usual contractual disclaimer "We're not responsible for how you use this connection" ought to be extended or replaced with a bounding statement such as "suitable for the requirements specified in Exhibit A." That exhibit defines whether the endpoints are connected to VPN routers or a pile of unsegmented network spaghetti.

3. Know what the options are for MPLS traffic engineering. Your situation may call for a dedicated MPLS cloud, heterogeneous options or another service altogether. Knowing your choices is the first step toward making a good one.