SPICE is a fairly advanced protocol as far as bandwidth. It can automatically adapt its behavior to client capabilities, network characteristics, and other parameters for the optimal user experience. For for some cases, it might decide that the client can handle raw graphics commands. On other systems it might lower the graphics output.
Unlike protocols such as ICA and RDP, which have two components, SPICE is made up of three components:
- Remote guest component - The Virtual Machine's (VM) virtual graphics adapter.
- Client component - SPICE client software
- Remote host component: A virtual graphics device made available to the VM with the hypervisor
The third component of SPICE, the hypervisor component, is a distinguishing feature compared to most protocols, which are two-tier. Having the hypervisor component means that SPICE will only work when your remote hosts are VMs. Right now SPICE can only connect to remote hosts running on KVM-based hypervisors, but now that the protocol is open source, third-parties can change that. There is evidence that the industry is moving towards the three-tier model. Microsoft and Citrix [http://hdx.citrix.com/hdx-3d] also have products with three-component virtualization protocols.
Red Hat says the open sourcing of SPICE will give vendors a terrific opportunity to enhance it for their specific applications. With SPICE as an open source component, will more people buy the Red Hat Enterprise Virtualization for Desktops solution? It depends on whether most customers are buying desktop virtualization platforms based on protocol anymore.
SPICE is one of three main technology components included in Red Hat Enterprise Virtualization for Desktops, which is currently in a private beta with a GA releaseexpected in 2010.