The benefits of Colocation facilities for the Next-generation Enterprise WAN

Together with either Network-as-a-Service and/or WAN Virtualization, Internet-based overlays leveraging colos deliver lower bandwidth costs, far better performance and predictable, reliable cloud computing access

Last time we began our discussion of colocation and how it relates to the Next-generation Enterprise WAN (NEW) architecture. This time, we'll look further into the benefits that colo facilities can bring to the Enterprise WAN, when combined with one or both of WAN Virtualization and colo-based managed network service.

For a quick synopsis of our last column: a colocation facility is a type of data center "where equipment space and bandwidth are available for rental to retail customers." Colocation based in carrier-neutral facilities offers cheap bandwidth close to the "core of the Internet," a way to build inexpensive, reliable, stable and relatively low-latency connectivity worldwide, and frequently offers low-latency connectivity to enterprise locations.

We ended our last column noting that the lack of a means to connect from enterprise locations to those colos that is both reliable and cost effective has until recently inhibited their use for data center consolidation or SaaS / cloud computing access. Two different technologies introduced in the last few years offer solutions to the last mile issue here. The first, WAN Virtualization, delivered by among others Talari Networks (my former company), we've covered before in this column, and is for enterprises that want to "build it themselves." The second, Network-as-a-Service (NaaS), as best exemplified by Aryaka Networks (my current employer), is for those who prefer to go the easier-to-manage, monthly service route.

With the WAN Virtualization approach, you deploy an appliance at each enterprise location and at the colo facility, and use multiple diverse Internet links of any type, which for branch offices will typically be broadband (DSL, cable, perhaps 4G). There are many benefits to this approach, including maximum bandwidth, lowest cost/bit, better-than-MPLS reliability and predictability, and the ability to augment and/or replace an existing MPLS network a site at a time. You are building your own highly reliable WAN as an overlay leveraging the public Internet.

With the Network-as-a-Service approach, rather than the CapEx acquisition of appliances, you buy a service from the provider, connecting each of your enterprise locations into the colo-based overlay via a VPN connection over the Internet, typically an IPSec VPN. Only one Internet connection is required, rather than two or more. For maximum performance predictability, you would buy a direct TDM or fiber-based connection from your enterprise locations to the closest colo facility operated by the service provider. The benefits of going the managed service route are avoidance of CapEx, faster deployment globally, elastic capacity with instant upgrades, and a service managed by someone else with 24/7 support.

In particular, the benefit of this approach is most seen when you don't currently own WAN Optimization appliances but want to benefit from WAN Optimization-as-a-Service as well. In addition to avoiding CapEx and the ongoing burden of management, the cost of these combined services is far lower than paying for WAN Optimization appliances and monthly MPLS service. This is especially noticeable in countries like China, India and Brazil, where the cost of WAN bandwidth is particularly high, and where, unlike in North America or Western Europe, MPLS service doesn't always perform well or reliably despite its expense.

WAN Optimization appliance architectures were designed for application performance optimization and deduplication over a reliable wide area network, and so often won't work particularly well over the unaided public Internet, especially if connecting locations across oceans. So WAN Optimization appliance approaches should generally either be run over MPLS, or in conjunction with WAN Virtualization where you are building your own reliable WAN via an Internet overlay. Alternatively, you can get WAN Optimization-as-a-Service combined with Network-as-a-Service as an Internet overlay, and let someone else do the management and cover the CapEx.

With either the do-it-yourself WAN Virtualization method or the Network-as-a-Service method, getting to the colo reliably allows you to quickly and far more cheaply add bandwidth to your network than MPLS can. Over the Internet, and especially across oceans, using WAN Optimization-as-a-Service by first accessing a colo facility provides better performance, in particular when all-too-frequent congestion-based packet loss or high latency occurs, as a colo-based overlay approach allows segmenting and much faster detection of and reaction to packet loss, as well as avoidance of high latency network paths. In particular, for very long distance WANs, a colo-based approach can ideally address several of the key WAN factors affecting application performance, including the "chattiness" issues of protocols like CIFS and HTTP.

A colo facility is the best place to do "Internet backhaul", as described here, especially if using WAN Virtualization to aggregate multiple links, as you get almost all of the benefits of the centralized and distributed approaches, with almost none of the drawbacks, and get additional cost and performance benefits not possible with either prior, non-colo-based approach.

Finally, such an Internet overlay-based approach getting your traffic first to a colo facility becomes the perfect way to do reliable access to cloud services - public cloud computing services and/or SaaS. At minimum, your traffic avoids most problematic Internet congestion points and needs only connect over the highly reliable Internet core. In many cases, you can do better still, and have a colo deployment - either your own or that of your NaaS provider - at the same colo facility, or at least at one very close to, the facility at which your cloud service provider or SaaS provider is located.

We'll explore in greater detail how this works in future columns. The point is that above and beyond the cost, bandwidth and performance advantages these colo-based Internet overlay methods deliver over using MPLS, they also offer a solution to migrating more of your computing to cloud services and SaaS than MPLS ever could.

Colocation facilities, whether used by enterprises directly, or via NaaS providers who leverage them, are set to play a critical leading role in next-generation enterprise WANs because of their ability to enable lower WAN bandwidth prices, increased bandwidth, faster deployments, and to improve application performance and predictability for both intranet applications as well as access to SaaS and cloud-based services.

A twenty-five year data networking veteran, Andy founded Talari Networks, a pioneer in WAN Virtualization technology, and served as its first CEO, and is now leading product management at Aryaka Networks. Andy is the author of an upcoming book on Next-generation Enterprise WANs.

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Copyright © 2012 IDG Communications, Inc.