V D I

Citrix uses the ICA (Independent Computing Architecture) protocol which is a proprietary
technology developed by the company over 10 years ago. ICA is used by both XenApp
and XenDesktop for remote desktop delivery. The company enhanced ICA with the
release of HDX (High Definition Experience) in early 2009. HDX is a set of ‘high definition’
technologies that complement the ICA protocol and allow for higher resolution
desktops/multimedia (e.g., flash video) to be delivered more efficiently and with better
quality over any network. Our industry contacts indicate that ICA is a superior protocol for
use over the WAN (i.e., for remote branches) and for connections with limited bandwidth.

VMware View primarily uses the PCoverIP protocol, which is licensed from Teradici.
PCoverIP is a remote display protocol that was developed for the purpose of delivering
virtual desktops. Mr. Viarengo of VMware opined that PCoverIP is a superior protocol
when very high resolution is required for desktops delivered over the LAN (e.g., doctors
viewing x-rays over virtual desktops). He also mentioned that while ICA has the reputation
of offering better performance over a WAN, View can also be configured to deliver similar
performance. The company commented that it is working on better communicating best
practices for how View must be configured for different network bandwidth scenarios. View
can also be configured to use Microsoft’s RDP (Remote Desktop Protocol) which appears
to be generally a less preferred technology to both ICA and PCoverIP. View continues to
use RDP to deliver VDI to certain mobile devices.

Tablet/Smart Phone Support
Citrix enables access to virtual desktops and published applications seamlessly across all
mobile devices including tablets and smart phones, through its Citrix receiver application.
Citrix receiver is a software application that sits on the mobile device and enables the user
to access their virtual desktop (XenDesktop) and published apps (XenApp).

VMware’s solution for tablet and smart phone access sometimes involves the need to use
third party applications. For example, at present, accessing View on the iPad requires the
use of Wyse Pocket Cloud client. Also, different devices use either PCoverIP or RDP, and
hence the implementation of virtual desktops across multiple devices is not consistent,
making it more difficult to support/maintain.