The role of software-defined networks in cloud computing

Grazed from TechTarget. Author: Tom Noelle.

It may seem ironic, but the most difficult thing about software-defined networking is actually defining it. Given the elasticity of views about what a software-defined network is, it's hardly surprising that SDN's specific role in the cloud is elusive. There are two software-defined networking models and two different SDN missions in cloud computing. Since networks create the cloud, managing the interplay between these two factors could be the key to cloud efficiency and success.

As an information service, the Internet treats the network as a transparent partner. With the cloud, a user's applications reside in, and become part of, the cloud. And most agree that means at least some of the network must be integrated with the cloud. The current consensus is that the data center has to be made cloud-specific, but should the WAN also be a "resource" to the cloud?...

To answer that, let's first look at why SDN must include the data center. In cloud computing, the user joins a community the cloud creates. Cloud computing service providers face the issue of multi-tenancy at the network level as much as they do at the CPU/server and database levels. Shared resources must be shared in such a way that one user's applications do not affect another user's apps. Therefore, the resources of all users have to be partitioned so they are private and secure. While network technologies such as IP and Ethernet each have virtual network capability, these capabilities are limited in terms of how many tenants can be supported and limited how isolated each tenant is...

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