Best BYOD management: Work zones for smartphones

Mobile Hypervisors

The third approach to containment is to create a virtual machine that includes its own instance of the mobile operating system -- a virtual phone within a phone. This requires that the vendor work with smartphone makers and carriers to embed and support a hypervisor on the phone. Such technology isn't generally available yet, but devices that support a hypervisor may eventually allow users to separate personal and business voice and data.

VMware is developing an offering called VMware Horizon. It will support Android and iOS, and function as a Type 2 hypervisor, which means the virtual machine runs as a guest on top of the native installation of the device's operating system.

Having a guest OS run on top of a host operating system tends to consume more resources than a Type 1 "bare metal" hypervisor that's installed directly on the mobile device hardware. It's also considered a less secure approach, since the host operating system could be compromised, creating a path of attack into the virtual machine.

Another vendor, Open Kernel Labs, offers a Type 1 hypervisor that it calls "defense-grade virtualization." Open Kernel's technology is currently used mostly by mobile chipset and smartphone manufacturers that serve the military. The company has yet to break into the commercial market, says Redman.

Developing a Type 1 hypervisor that interacts directly with the hardware is impractical, says Ben Goodman, lead evangelist for VMware Horizon. "We moved to a Type 2 hypervisor because the speed at which mobile devices are being revised makes it nearly impossible to keep up," he says.

As for security, VMware is working on an encryption approach similar to the Trusted Computing Group's Trusted Platform Module standard. It's also researching jail-break detection.

Performance won't be a problem, says Goodman, vowing that "VMware Horizon is optimized to run extremely well." But VMware declined to provide the names of early adopters who could discuss the product.

Israeli startup Cellrox offers its own twist on virtualization for Android devices. The technology, called ThinVisor, was developed at Columbia University. It's neither a Type 1 nor a Type 2 hypervisor, but "a different level of virtualization that resides in the OS and allows multiple instances of the OS using the same kernel," says Cellrox CEO Omer Eiferman. The vendor offers ThinVisor to cellular service providers, smartphone manufacturers and large enterprise customers.

Problems and Promise

One problem with containerization is that not all products support iOS, which powers iPhones, the smartphones most commonly found in enterprises. While Apple has a 22% share of the worldwide smartphone market, compared with 50% for Android devices, those figures are reversed in the enterprise: The iPhone has 60% of that market, versus 10% for Android devices, according to Gartner.

Apple's legendary secrecy about operating system enhancements means containerization vendors receive no advance notice and must scramble every time the vendor releases an update. The bottom line: Users may have trouble accessing corporate systems if they upgrade their personal iPhones too quickly. At University Hospitals, says Terry, "iOS changes often cause service interruptions while Good Technology's products are modified, tested, then released."