VMware Blast protocol
With the release of version 7 of Horizon View, VMware has decided to release a new video rendering protocol for the desktop virtualization part called BLAST.
From the technological point of view, at least at a general level, this is not new, since it has been used for some time to connect to VMware virtual machines through the HTML5 client.
The encouraging results of the Blast protocol have led the company to persuade them to use it for connections also made through the Horizon View client. If technologically speaking it is not a revolution, it is actually about technology partnerships: it substantially modifies VMware’s technological dependence on Teradici, the Canadian company that holds the rights to implement the PCoIP protocol.
Just for the record, VMware claims that there are not different functionalities between the two protocols today and wants to keep developing on both technologies. We will see how it will turn out. To date, the only thing we can notice in this respect is that in Horizon products many of the terms that indicated PCoIP disappeared.
As for the protocols and encodings used, Blast does not radically change things from what the market already offered: it uses a H264 encryption on TCP connections, unlike PCoIP that works in UDP over JPEG encoding. Generally, switching from JPEG image encoding to H264 means allowing less-powerful clients to be used, but with H264 hardware decoders, now widely used on thin clients or modern smartphones. The risk, however, is to increase the workload of the server.
Switching from a UDP-type protocol to a TCP, again at a general level, means reducing the hoverhead in packet exchange in the case of reliable networks with reduced latencies. On wireless networks, often characterized by latencies and packet leaks, TCP is usually more expensive and less efficient when using the available bandwidth.
This is obviously a general concept, in the various real cases the behavior of the two protocols must be analysed. However, I do not think an absolute winner in terms of performance could be ever declared, external factors will be the ones to decide case by case the best protocol.
VMware’s strategy is, however, to use technologies that, at least as far as Blast is concerned, will overcome structural protocol constraints, for example, the partnership with Riverbed, one of the leading technologies in WAN optimization, is countercheck.
Increasing the load on the server could in some cases make the virtualization system less scalable, and that’s why VMware has developed the ability to add a graphics card inside the server and to take advantage of its H264 encoder. With the accelerated graphics card the protocol takes the name of Blast Extreme. It reduces image encoding times on the server, bringing de facto the VMware servers in line with the scalability levels we know.