Over the past several years of deploying software-defined WAN, there's been a shift in the way enterprises move...
from MPLS to SD-WAN technology. Increasingly, the question has become less about if SD-WAN will be adopted and more about how to shift to SD-WAN.
After assessing the SD-WAN options -- preferably with input from consultants -- organizations must still go through the practical steps of moving off MPLS. Here are some of the less obvious actions to take to ensure a smooth transition in your MPLS-to-SD-WAN migration.
1. Read your MPLS contract
For starters, when migrating from MPLS to SD-WAN, you need to understand some basics about MPLS contracts. MPLS contracts are normally structured on a multiyear basis -- typically three years. Service pricing includes an MPLS port charge and a local loop charge. The MPLS port charge is for the actual MPLS services, while the local loop charge is for leasing the infrastructure from the local carriers. Service-level agreements (SLAs) and break terms are spelled out in the contract.
Your contract should clearly describe how quickly and easily you can break away from MPLS. Carriers know this, so they may be reluctant to provide a copy of the contract if you don't have one. This is a problem, particularly for companies that have gone through mergers and acquisitions in which the people who negotiated the service are no longer with the firm.
At other times, foreign carriers might provide only a native-language version of the contract. If that's the case, hire a professional translator, if necessary; it's well worth it. Bottom line: Do whatever you need to do to get hold of that MPLS contract early.
2. Assess termination charge and minimum commitment
Once you get a version of the contract, you need to understand a few things. The first is the termination charge. Most MPLS contracts penalize you for early termination. The provider might say you can break the contract, but you have to continue paying a charge for the contract term as if you were still using the network.
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MPLS providers need the termination charge, in part, to protect them against local loop costs. They lease the local loops from the carrier and are locked into them for the duration of the contract. Understanding this fact might give you some negotiation leverage. You can look into paying the local loop charge, for example, and save on the MPLS port costs, which constitute about 30% of the overall costs.
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Next, investigate the clause laying out the minimum commitment. MPLS contracts often commit you to annually spend 70% to 80% of your actual annual spend. If you've increased your MPLS usage for any reason during the terms -- due to new locations or traffic surges on variable rate ports, for example -- you could find that you've met the minimum break requirements well before the term completion.
3. Move to month-to-month MPLS services
Ideally, you are able to schedule your transition from MPLS to SD-WAN when the MPLS contract is up for the term. If that's not possible or if you need flexibility -- to give you time to install internet lines, for example -- you might have other options. MPLS providers often permit you to go month to month if you negotiated this at the start of the contract.
Keep in mind that monthly MPLS contracts can be expensive. Carriers discount MPLS port prices on multiyear contracts by as much as 60%. Once you go month by month, you often lose those discounts.
4. Measure the latency to remote sites
Despite all the talk about eliminating MPLS from the corporate WAN, in some cases, you may need an SLA-backed backbone or some additional circuits to provide dependable performance. While no hard rule exists for when you should consider a private backbone, a good guideline is when the latency to your data center exceeds 180 to 190 milliseconds.
You can access private backbones using a VPN from your SD-WAN appliance to connect to providers such as Azure, AWS and Mode. Another option is to keep a few MPLS circuits for latency-sensitive traffic.
5. Order internet lines ASAP
This can't be said enough: When undertaking an MPLS-to-SD-WAN migration, the moment you know you need internet lines, order them. Yes, SD-WAN can deploy faster than MPLS, but don't be fooled -- that's when compared against low-cost broadband circuits. For high-quality, dedicated internet access, you need the right fiber plant, and that can take nearly as long as getting MPLS in place.
The consequence of waiting can catch enterprises by surprise. At one Fortune 100 customer of mine, I advised early on to start ISP installations. It waited, and when it wanted to cut over from MPLS, internet access wasn't available. The result: It ended up paying $250,000 more in MPLS charges as it waited for internet fibers to be pulled to its various premises.
Once you've made your decision to go with internet, place the order. Leave at least 10 to 12 weeks to get internet circuits installed. You need to identify the minimum point of entry (MPOE) for each location, which is the point at which a telecommunications provider's wiring crosses or enters a building. This often occurs in a box on the outside of the building or possibly in the basement. It's an area in your building that usually looks like a closet or a box. Here are some sample photos to send to your branch offices to identify the MPOE.