Eye on the Carriers By Johna Till Johnson, Network World, 09/29/06

Most of my clients are making the move to MPLS. They're either actively considering MPLS-based services, testing them or embarking on a migration. I've learned quite a few lessons:

• Expect to save 25% to 40% compared with your existing voice, data and video services - but with some caveats. First, the greatest savings accrue to folks who combine all three (thereby eliminating such things as redundant ISDN networks for video). Second, the greatest savings apply to highly distributed, relatively low-bandwidth networks (that is, dozens or hundreds of T-1 sites). A network with relatively few high-speed sites (a dozen OC-3s, for instance) may not see the same savings. Finally, your mileage may vary: The savings aren't guaranteed. Some companies have found that because of previous competitive negotiations or unusual network configurations, MPLS doesn't provide any savings.

• If you're planning, along with rolling out MPLS, to converge voice and data via VoIP, tackle each project separately. Carriers recommend starting with MPLS and pursuing VoIP later; I wouldn't say you need to hold off on VoIP while launching your MPLS network, but make sure to devote enough resources to both. Keep in mind the impact VoIP will have on your service contract. Don't commit to a voice-only minimum annual revenue commitment, for instance, if you're planning to convert voice to VoIP during the duration of the contract. Plan the anticipated capacity of your sites appropriately - if you need to increase bandwidth to accommodate voice and video traffic, make sure your access circuits can handle the load and your contract doesn't include clauses that make increases prohibitively expensive.

• Get the scoop on network-to-network interfaces (NNI). Try to keep your sites on a single carrier's network - with the possible exception of having multiple carriers link to critical sites for redundancy - because effective MPLS NNIs are lacking. For starters, carriers have different service class definitions, so you'll have to map provider A's platinum class to provider B's Tier 1 class - and each has different characteristics. That's if provider B is offering MPLS at all: In some cases, MPLS NNIs are really handoffs to frame or ATM. Keep in mind that few providers will offer end-to-end service-level agreements to off-network sites. More broadly, the most effective cross-carrier connections are between providers that have previously established working relationships. In other words, each carrier has a short list of providers it works with - ask for that short list, as well as the details of the technical and business relationships. Plan to drill down, asking questions such as: What is the certification process for adding providers to this list? What service guarantees can be made, and how are they enforced? How is troubleshooting handled? The more you know, the more effectively you can manage crosscarrier connections.

• Finally, take the time to plan an effective migration from legacy services, such as frame and ATM. To find out how, stay tuned for next week's column.