Guaranteeing application performance over a WAN is hard enough. Now try doing it in a virtual environment.
WAN optimization vendors big and small are developing versions of their products specifically for guaranteeing performance of virtualized applications delivered to remote offices from data centers. In so doing, they are looking to address challenges companies face in providing LAN-like performance for application delivery while availing themselves of the reduced cost and increased flexibility that virtualization provides.
"The biggest issue when you're looking at virtual traffic is the fact that, much like voice, much like video, it's live," says Chris Silva, an analyst at Forrester Research. "If you're accessing it remotely and there's a glitch, you may have an application timeout, you may literally lose connectivity. It's really critical to have real-time interaction speed with that environment when you're working in it virtually. Think about it like any other live, real-time protocol."
Desktop virtualization products like VMware's Virtual Desktop Infrastructure (VDI) are designed to replace traditional PCs with virtual machines managed from the data center. The potential benefit is a reduction in operating cost, increased control of desktop management, and extension of critical services, such as business continuity and disaster recovery, to enterprise desktops.
But when desktop virtualization is deployed over the WAN, latency and bandwidth constraints limit its effectiveness. According to Cisco, which has an arrangement with VMware for optimizing VDI over the WAN, customers face several challenges in deploying virtual desktops:
-- Poor performance of Microsoft's Remote Desktop Protocol (RDP) over the WAN.
-- High bandwidth consumption.
-- Limited scalability, reducing the number of users that can be supported.
-- Poor performance of centralized printing and increased costs of printing at the branch office.
-- Considerable time and bandwidth required for transfer of virtual images.
-- Continuous availability needed within and across the data center for the VMware VDI.
-- High server resource consumption for SSL functions, resulting in a large number of servers.
Cisco says its Wide Area Applications Services (WAAS) product can accelerate the performance of all applications accessed through VMware VDI, including Microsoft Exchange, PowerPoint, Excel and Word, by reducing RDP bandwidth demands by 70%. The company also says WAAS can increase by fourfold the number of VDI users an infrastructure can support, and improve print operations by 70%. The appliance is designed to accelerate virtual image backup by 50 times, thereby reducing bandwidth by 90% for business continuity functions; and providing a 60% to 70% reduction in overall bandwidth requirements.