When purchasing WAN services, you face a slew of drivers that you have to try to balance. First and foremost, you’re always concerned with the cost of connectivity options. The connectivity needs to appear seamless to your users and applications. In fact, as network operators, our goal is for the users to not even remember the network is there. You’ll also want to consider how the solution scales to 1, 5, 10, or 50 locations. And finally, you’ll always have to work with your security folks to make sure it meets your existing security plans (or regulatory requirements for security?
Then you have the drivers that you, as an IT department need to see from the connectivity (internal drivers). You want it to be dependable, predictable.You want it to be dependable, predictable. You want solid support from the provider or providers, when there is a problem. You need a technology that you've worked with before, or is well known in the industry, so that there is plenty of knowledge in-house for working with it.
For those reasons and others, we're going to focus in this article on the process for purchasing Ethernet based WAN services. You may have heard me refer to them as Metro Ethernet services or Carrier Ethernet services. I'll try to stick to Carrier Ethernet services for the remainder of this piece.
First, let’s consider some of the practical aspects of the decision. Let’s talk about reach, just how many of your locations, can a given provider touch? Is there a provider that's a clear leader in touching all (or the majority of your campus locations?) If not, is there one that has cooperative agreements that allow them to sell (via 3rd provider partners) in all of your locations?
How much is simplified support and one call management worth to you?If there is one clear leader, is that a benefit your enterprise values (having all or most of your contracts under one roof)? Does this advantage give this provider a cost advantage as well? It’s not just the simplification of contracts, you’ll want to ask yourself “how much is simplified support and one call management worth to you?".
Also be cautious about accepting the marketing definition of coverage areas from most providers in the Carrier Ethernet space. Many will provide you with their "Regional coverage maps" that detail where (in general) they provide their Ethernet services, but this doesn't always mean they've got fibre or "last mile" connectivity to your actual locations. I recommend providing actual street addresses of each and every branch office (right down to the demark location of multi-floor buildings).
Ask all of your providers to certify that the service can be provided to these locations without an added build-out cost. If there WILL be build-out costs to get the last mile to some of those locations, make sure they're detailed up front and in writing to prevent surprises. If you opt for multiple providers, make sure you have a plan for where you will keep that knowledge base of circuits, providers, support numbers, support hours, SLAs and support escalation contacts?
Because at some point you, and others in your world will want to go on vacation, so that information can't remain in just a few craniums. Next let’s talk about Availability, reliability, and supportability. In the end, these are the services that will form the foundation of your global business. You make your phone calls across them. You make sales, contact customers, hold meetings, and often, even deliver product across these lifelines, so they have to be there twenty four hours a day, seven days a week, and 365 days a year.
An ironclad SLA with each and every provider that provides one of these circuits is going to be crucial. If you're going to have multiple circuit providers involved, you're going to want to do your best to get the terms of those contracts and SLAs to line up as closely as you can. A single SLA should define targets for frame latency, diversity (if desired), and uptime availability, fix times in the event of a failure, and jitter (among other metrics).
Trying to keep track of 8 different SLAs (across 30 or 40 circuits) and the guarantees in each is going to be like pushing water uphill with a rake. As you might have already surmised, finding circuit providers with solid foundations and reputations in the industry is also important. Saving 10% on the contract may not be worth it if being down at a branch for even a day would be catastrophic for your enterprise.
You’re going to also have to figure out what you’ll use for CPE to terminate those Ethernet connections at the branch offices. If you're doing this procurement one location at a time, this is easier to deal with, because you’re only dealing with a single installation at a time. If, however, you're doing a large VPLS (Virtual Private LAN) contract and many locations at once, you're going to want to give some thought to who will be providing the CPE, what brand and model you'll use, and whether it's flexible enough to handle multiple connectivity types. Some Ethernet installations will hand you copper into your WAN port, some will be Single-Mode fibre and some will be Multi-Mode fibre.
You’ll need something that can accept any of the three. Also ask yourself does the CPE give you the ability to roll security and Ethernet termination into one platform, or will you use a different device for things like VPN endpoint and security inspection? If you're doing that one-time, large overhaul of circuit contracts, you should even be considering whether it's time to partner with one (or more) providers to manage the Ethernet CPE at the site so you can focus on the Security appliance behind it. It's also worth considering whether you may need multiple CPE devices at larger branches where you need a higher level of diversity (redundancy).
Even at sites that only have a single circuit (and therefore a single CPE, it might be wise to go with a CPE that has dual power supplies if you can get "A" and "B" side power feeds at the site. If, in fact, you are working in an enterprise with branches all over the globe, you have a LOT of other factors to be concerned with. For one, you will almost certainly be dealing with Multiple circuit providers in different countries. Everywhere these circuit providers meet one another and hand off a single circuit "across borders" from one network to the other, this is called an NNI (or ENNI to be more specific).
The ENNI is the breakpoint between two individual networks with different administrative authorities, different hardware (most likely), different internal policies and SLAs, and possibly even different local telecom laws and regulations. For that matter, the staff at the two providers may not even speak the same first language.
Now, in practice, they most likely work with each other all the time, but each of these complicating factors presents a potential for miscommunication or problems when you are ordering the circuit. They can also present problems down the road when you are trying to get support and the finger pointing starts. Make sure you have a solid SLA from the provider you purchased the circuit from (the primary provider) and make sure it's clear that they are responsible for the circuit from end to end (even if there are multiple providers and ENNIs involved. If that's not the case, at least make sure you have a clear support structure and know who to call and how to troubleshoot the circuit up front.
Procuring and delivering WAN services is a complex endeavour. Carrier Ethernet services are no exception. There are always going to be lots of things to consider. From circuit vendors, to hardware vendors, to contract terms, SLAs and pricing models. In fact, often it seems like as soon as the process is over, we have contracts expiring and it’s time to start this Sisyphean task all over again. But with planning and forethought, you can come out ahead and put your business in a position to win.
An article on VPLS providers