Last week, we discussed some of the "lessons learned" from early adopters who are moving toward MPLS. This week, we're covering some of the specifics for migrating to MPLS from legacy services, particularly frame relay.

First and foremost, make sure you plan to invest the necessary time upfront. One of the most common questions I get is "how long will my migration process take?" There's no easy answer - it depends on the number of sites, the number of geographies and your starting state. But here are rough guidelines:

Any comprehensive RFP process should be started a minimum of six months before the desired circuit turn-up. Eight months is better. Very early MPLS adopters invested several years in discussions with their carriers. That's no longer necessary, but unless you're very small, six months to a year is optimal.

Next, make sure to inventory your applications. Companies know the details of their hardware down to the operating system version and configuration specifics - but don't have the faintest clue about the applications that traverse their networks. Here are some things you should look for:

• Inventory and itemize your applications. Which do you have, how many are there, and how often are they used?

• Profile the applications. Next, understand the network characteristics of your applications. Are they store-and-forward? Or interactive? How "chatty" are they? In typical usage scenarios, how much bandwidth do they consume? How does that vary by time of day/week/month/year?

• Understand the users. The network manager at one large client was getting flak because network use was "too high" - until he demonstrated the heaviest users were programmers developing a critical application. Suddenly, high network utilization was no longer a problem.

• Be sure to include in your analysis applications that may be on other networks (particularly video and voice). You'll need this information for capacity planning.
  

Budget for ongoing monitoring. Your carrier will assure you that the provider will monitor everything you need. Trust, but verify - you'll want tools of your own to keep the carrier honest.

Assess your backup options - in many cases, backup for frame networks is provided by the same ISDN network that doubles as a videoconferencing infrastructure. With MPLS, not only is your overall bandwidth increasing but your ISDN network may be going away. Ask carriers to discuss backup options in detail.

Last but not least, don't forget the people part of the process. Moving to MPLS is likely to involve significant changes in your overall organizational structure. What are they? We'll discuss next week.