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More than 95% of enterprises use software as a service (SaaS) applications, more than 50% use infrastructure as a service (IaaS) and more than 40% use platform as a service (PaaS). By 2020, the average enterprise may have more than half of its applications in external clouds. Yet the overall depth of commitment to the public cloud is still pretty low -- the median amount of work folks are putting in the public IaaS, for example, is only about 3% of overall workloads.
Public cloud concerns
One reason that enterprises are cautious about shifting work to public cloud platforms such as Amazon AWS, Google Compute, IBM Softlayer or Microsoft Azure is the unpredictability of the public internet in delivering packets to or from those services. It's not just latency. Packet loss can vary dramatically from one moment to the next.
If an enterprise wants to put parts of a service-oriented architecture in the cloud -- but not all of it -- many "east/west" conversations will have to cross the internet rather than traverse predictable and reliable internal networks. This could cause performance to vary widely, something users like even less than start-and-stop data traffic."
Another reason for caution is security: Organizations of all kinds are still finding their level of tolerance to risk committing mission-critical, sensitive or protected classes of information to cloud resources and internet connections. More and better options for encryption go a long way to allay the fear, but the "public" part of the public internet is still a big hurdle.
WAN-cloud extends to CSP edge
In answer to these problems, cloud service providers (CSPs) and technologically aggressive organizations that wanted to take greater advantage of the cloud hit upon a solution: Extend the private WAN to the edge of the cloud service provider's network. With this approach, an enterprise would get a network presence established in a data center that also hosted part of its CSP's network. In addition, the enterprise would get fiber pulled to connect its router to its CSP's router. Some Border Gateway Protocol magic to reroute traffic from the public internet link to the private WAN-edge link, and voila! No more public internet transits needed to get to the CSP's services, and achieve WAN-cloud goals.
After enough enterprises made this kind of arrangement, carriers and colocation providers hit upon the idea of setting up something called a WAN-Cloud eXchange (WAN-CX) that make it easier for both CSP and the enterprise.
A WAN-CX provides a communications aggregation point via which a CSP can provide access to multiple enterprises, through which an enterprise can gain access to many CSPs. Enterprises get a connection set up from their WAN to the exchange; the exchange provider pre-provisions (and expands as needed) connectivity to CSPs on the exchange. Enterprises can connect to participating CSPs by simply setting up virtual circuits via a portal, without waiting for any further fiber pulls. Both carriers and colocation providers offer these services, among them AT&T NetBond, Level 3 Cloud Connect, Verizon Secure Cloud Interconnect, Equinix Cloud Exchange and TelX Cloud Xchange.
Enterprises should examine the WAN-CX options available to them when their use of cloud warrants it. Some examples could include the following:
- When baseline traffic volume to and from a cloud provider gets high and continues to rise;
- When packet loss via the public internet becomes too high or variable for end user satisfaction;
- When latencies via the public internet becomes too high or variable for end user satisfaction;
- When either loss or latency makes performance for on-premises service components too variable;
- When security concerns regarding use of public internet interfere with pursuing organizational cloud strategy; or
- When enterprises have already done links one-off in the past and find they want to extend private connectivity to more CSPs or want to be able to switch CSPs easily without losing the benefit of the private connection.
As more enterprises get to the point where they want and need private access to public cloud services, use of WAN-CX will surely rise. All enterprises with WANs should be keeping the WAN-cloud option in mind.
How WAN intersects with cloud services
The benefits of WAN-cloud exchanges with public cloud
Building a better WAN cloud architecture
How WAN managers need to assess the cloud