Within a week of VMware's announcement of its $1.2 billion acquisition of Nicira, software maker Oracle has revealed that it is buying the privately-held, San Jose, California-based network virtualization software maker, Xsigo Systems.

Both the VMware and Oracle deals show that, with leading vendors looking to becoming bigger players in the cloud space, software-defined network (SDN) and virtual networks are increasing becoming key to cloud computing environments.

While VMware is largely hoping to leverage the products from its Nicira acquisition - including Nicira's Network Virtualization Platform - to create a so-called software-defined data center which will substitute the conventional hardware-based facilities; John Fowler, Oracle's Executive VP of systems, has revealed that Xsigo will become a key component of the company's cloud computing efforts.

Despite the fact that both VMware and Oracle already had their network virtualization efforts underway before the acquisitions, their respective purchase of Nicira and Xsigo will allow them to take over the technologies of those vendors, as well as their customer bases.

Nicira will bring on for VMware some high-profile customers, such as eBay, AT&T, and Rackspace Hosting; while Xsigo's acquisition will give Oracle the access to nearly 300 customers, including the likes of EMC, Salesforce, eBay, Avaya, and McAfee.

About Oracle's Xsigo acquisition, ISI Group analyst Brian Marshall said that the purchase - close on the heels of VMware's Nicira takeover - was "a testament to the momentum behind software-defined networking and network virtualization technology."