Cloud computing's impact on the network: How to prepare

Cloud computing is catching on, but its impact on the network must be considered before companies begin running significant applications in the cloud. How data is sourced and stored, as well as how the application is distributed over the network, are important factors to understand and plan for.

Cloud computing is one of the hottest topics in all of information technology today. This is the outsourcing of data center functionality and resources to a third party via a network connection. For many companies with highly variable IT needs, cloud computing can be an alternative to maintaining an expensive oversupply of in-house computing power. The challenge may come in ensuring that your network costs don't eat all of the savi...


There is no such thing as a "typical" application of computing. Companies use IT for highly distributed activities including transaction processing, Web retail and customer support, data analysis and mining, and regulatory reporting. If these applications are hosted via cloud computing, it will be necessary to link cloud resources to a company's own data center resources for data access, and it will also be necessary to provide user access to the applications in the cloud. How this will affect the network will depend on three important dimensions.

The first is the source data dimension. Applications running in the cloud will need data, and where they get it is the most significant single factor in the network's impact on cloud computing cost and performance. Where there are large quantities of data involved (a large database or several large databases) in an application, access to the data must be fast and reliable or the application's runtime will be excessive. That means you'll either need to store the data in the cloud (which may present cost and privacy concerns) or have a very fast network with very high QoS to support your cloud connections.

It's also critical to consider a second dimension, the question of source data updates and backup. If the source data for the application is highly dynamic, or if it has to be backed up or synchronized with other company data, the link between the cloud data resources and enterprise data resources will need to be very efficient. Where the data is more static, network requirements for maintaining the data will be less stringent and there may be little impact on a company's network.

The third dimension is the distribution of access. If the application is to be accessed from many locations in many countries, most of the access will probably have to come via the Internet or an Internet VPN. If access is primarily from a company's own facilities, then it may be necessary to connect the cloud computing resource to the company's own network.

Where a cloud application is highly integrated with a company's own data center resources for any reason, the performance of that connection is absolutely critical. If it fails, not only is there a risk that the application will fail, there is a risk that data between the cloud and the enterprise's own storage resources will lose synchronization, requiring a complex and expensive restructuring. Thus, this kind of cloud application should probably be supported with a private data link to the cloud computing resource. Tight integration between cloud computing information resources and the data center may also increase requirements on the data center network and on any trunk connections between the data center and other primary or regional headquarters locations.

The Internet and Internet VPNs can be used to provide cloud computing communication, provided that the quality of service and availability are adequate, that the cloud resource can be properly secured, and that the connections needed between the cloud resource and the enterprise IT infrastructure are robust enough to handle the traffic. Companies often neglect the traffic generated by their own employees' access to cloud resources if that access is provided by the enterprise WAN through an Internet portal. Since these portals are normally maintained in or near the headquarters location, cloud computing may increase branch network traffic significantly.

The most difficult application class to support effectively in cloud computing outsourcing is simple "overflow" or backup applications where traditional enterprise applications are run in the cloud instead. This class of application can create enormous data access requirements unless the entire enterprise database is hosted in the cloud, something few organizations would consider. If this application of cloud computing is supported, the only effective strategy will be to create a high-speed connection between the cloud computing data center and the enterprise data center, so that traffic can then jump to the normal enterprise network.

The easiest application of cloud computing to support in the enterprise network is one where access to the application is via the Internet/VPN, where the cloud computing host can be joined to the VPN, and where little synchronization of data is needed between the cloud host and the enterprise data center. In this case, there will be little traffic impact on the enterprise network, but the support of a cloud resource as a member of the VPN will pose security considerations that will have to be resolved both in a technical sense and through a contract with the cloud computing provider.

Nobody should jump into cloud computing on a massive scale; it must be managed as a careful transition. A smart enterprise will trial out applications of cloud computing where network impact is minimal and gradually increase commitments to the cloud as experience develops. That way, network costs and computing savings can both be projected accurately.

About the author: Tom Nolle is president of CIMI Corporation, a strategic consulting firm specializing in telecommunications and data communications since 1982. He is a member of the IEEE, ACM, Telemanagement Forum, and the IPsphere Forum, and he is the publisher of Netwatcher, a journal in advanced telecommunications strategy issues. Tom is actively involved in LAN, MAN and WAN issues for both enterprises and service providers and also provides technical consultation to equipment vendors on standards, markets and emerging technologies.

This was first published in March 2009

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