cal solutions -commercial, commercial open source, and pure open source. Each solution has its own benefits and shortfalls and should be vetted based on the desired outcomes of the enterprise or the service provider. 4.2.3.1 Commercial Commercial vendors provide proprietary solutions to VIM demand. These proprietary solutions help customers transform existing IT infrastructures into private clouds, but at the cost of losing the ability to customize the environment to suit their needs. The most notable current vendor in the commercial VIM space is VMware with their vSphere product. 4.2.3.2 Commercial Open Source Commercial open source is a platform that is based on an open-source platform such as Apache CloudStack or OpenStack, but relies on a third party to provide an enterprise/proprietary edition or extension for the right to use software, at a cost. The proprietary nature of the software often means Building the Network of the Future that the vendor is in control. As the user, you can be placed in a position where you may not have access to public documentation such as transparency to bugs, or to source code, and when source code is provided, it may not provide the test frameworks to validate production readiness. Notable current vendors in the commercial open-source space are Red Hat, VMware, and Oracle. 4.2.3.3 Pure Open Source Pure open source as a VIM solution meets three defining characteristics-no license cost, a vibrant open foundation community, and an accessible source code that is readily available for download from the sponsoring organization. Rather than charging for the software itself, vendors can provide quality software with no license cost and then secure support arrangements and professional ser- vice assistance to generate profit. With a large, pure open-source community, you create a forum where individuals in different companies can share knowledge, bounce ideas off of one another, and spread support around more widely across a larger base. This results in faster introduction of fea- tures