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Buying a WAN link used to be pretty easy: ask your provider for the link, wait for it, and then light it up and...
use it. You likely paid more than you wanted, you waited longer than you wanted and you had few options to choose from -- so you had no sense of opportunities lost most of the time.
How things have changed. Today, every time you want to connect a new location to the WAN, you have choices, sometimes lots of them. Even if you have a primary WAN provider, chances are you'll have options with them, and that those will not be the only ones you examine. But you can still easily miss out -- on value, on performance, on agility -- depending on the choices you make.
How to connect?
MPLS? Sure, it's tried and true and the backbone of most enterprise WANs -- now and for some time to come. It pushes routing for your WAN into the carrier's lap and leverages a decade of engineering effort dedicated to providing rock-solid performance. For networks that are huge in terms of distance or number of sites, MPLS remains the ideal choice.
But MPLS does all that at a price, and it is sometimes more than is needed or wanted. As a result, lots of folks will be spinning carrier Ethernet services instead. This keeps routing in the enterprise's hands -- for good or ill -- and gives IT the benefit of just managing IP and Ethernet throughout the network. It also can provide buckets of bandwidth comparatively cheaply, albeit with lower expectations for uptime, packet loss and jitter. For data center interconnects, or WANs that mostly cluster around a few central sites of data centers, Ethernet is often ideal.
Wired links don't stop there: DSL and cable modems are increasingly common connectivity options for small and even midsize locations -- if not as primary connectivity, then as secondary links. While these broadband options may suffer by comparison with Ethernet on bandwidth, they can be quite attractive in terms of the speed with which they can be deployed, their low cost and their ubiquity. In cases where a business is frequently spinning up, or moving, small branches, these consumer-style options can be quite attractive.
For all of their capabilities, however, DSL and cable modems are getting some stiff competition lately from 4G, in part because 4G coverage has rapidly expanded and improved across the United States. Using 4G as a foundation, IT can spin up a new branch nearly instantly. Primary connectivity then can shift to broadband, Ethernet or MPLS as deemed necessary. Keeping 4G as a secondary link -- whether actively used for regular traffic or passively used for failover -- remains an option no matter what other connectivity is deployed.
We also see metro Wi-Fi becoming a small-branch option in some places, especially as cable-anchored hotspots proliferate. Metro Wi-Fi offers all the same benefits as 4G, minus the breadth of availability. Satellite connectivity, meantime, is also drawing renewed interest, fueled by the availability of middle-earth-orbit networks that offer higher throughputs and lower latencies than older sat nets.
And for just about any site, we see a strong interest among enterprises to provision their branch offices with multiple WAN links. With the advent of software-defined WAN (SD-WAN) and its ability to make all these links an intelligently and actively managed pool, redundancy is no longer an unaffordable ideal.
What to connect to?
Usually, your branch offices will connect right to your WAN, but not always. Here, too, there are a number of options.
Instead of going right to your WAN -- and again with a healthy push from SD-WAN -- more sites than ever are being connected to the internet instead, with a WAN link tunneling through that internet connection. It used to be that an internet VPN (iVPN) connection would only be used if the primary, usually MPLS, link failed. Increasingly though, iVPNs are being used as alternate primary links, either via static routing of some traffic across them or, in SD-WAN deployments, via dynamic traffic balancing.
Once you are not connecting directly to a WAN, you have another option: connecting to a network-as-a-service (NaaS) provider. In this case, instead of aiming the iVPN at your own data centers, you aim it at the NaaS provider's; the NaaS service provides the middle-mile connectivity, usually using capacity leased from a multitude of carriers. NaaS connectivity can be mixed and matched with conventional WANs to provide alternate connectivity or primary connectivity -- and for some or all classes of sites or types of traffic.
Clearly, IT is entering a new golden age of WAN connectivity as the options for access and architecture continue to multiply. That said, having so many options is both a blessing and curse. Network teams should be proactively thinking through their options and building decision trees to use to make quick, consistent resolutions every time an opportunity presents itself. This may take some effort, but the results in improved performance, agility and cost management will be well worth it.
MPLS reigns, but internet catching up
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