Review: Riverbed closes the WAN gap
Riverbed Steelhead with RiOS 7 takes a huge bite out of UDP, video, and VDI traffic over the WAN, adding to its excellent TCP and file access optimizations
The most exciting addition to RiOS 7 is the UDP optimization. Long missing from RiOS, UDP support takes the form of a packet-by-packet optimization engine aimed at reducing data sent to remote sites during a disaster recovery (DR) backup session. Many DR solutions, such as those from Veritas and Aspera, use UDP to stream the data to the destination. In previous versions of RiOS, this traffic was simply passed through the appliance without deduplication. Considering the large amounts of redundant data in the typical backup set, this was a glaring hole in Riverbed's arsenal. Now, RiOS 7 will apply the same Scalable Data Referencing (deduplication) algorithms to UDP and cache data segments for future reuse.
One instance where UDP traffic is still going to be passed through unoptimized is VMware's PCoIP protocol for VDI communications. PCoIP is UDP-based, but the packets are compressed by VMware to speed up VDI connections. Because of this compression, RiOS 7 cannot properly analyze the contents of the UDP stream and therefore cannot optimize it. Riverbed is a member of the Teradici Network Solutions partner program (Teradici developed PCoIP), so work is being done to add full PCoIP support to RiOS; as of now, there is no timetable for its completion.
TCP-based VDI traffic gets a boost with an enhanced Citrix-specific software blade in RiOS 7. Instead of applying generic TCP optimizations to Citrix ICA traffic, RiOS 7 can apply ICA-specific optimizations, even to SSL-encrypted ICA streams. RiOS 7 also supports Citrix client drive mapping, meaning it can optimize the data flows between USB sticks and other drives plugged into remote thin clients and virtual desktops in the data center.
Remote Desktop Services sessions also benefit from TCP optimization, but with a caveat. In order for RiOS to provide any data reduction, admins will have to disable Remote Desktop's built-in compression and encryption. I had to turn off compression completely and take encryption down to its lowest level to see any data reduction. As with PCoIP, if the RDP stream is compressed, RiOS cannot optimize it beyond simple TCP optimizations. Using Login VSI, I scaled my remote access tests up to 25 concurrent users on a Windows Server 2008 R2 Remote Desktop Server and held it steady for a full 15-minute Login VSI test run. During this run, I saw a 57 percent reduction in WAN traffic. Disabling compression has to be done on each client, but it's certainly worth the effort.
Riverbed requires compression and encryption to be rolled back in order to optimize Remote Desktop Services traffic, but disabling them pays off. Using Login VSI to run 25 simultaneous Remote Desktop Services connections over my simulated WAN, I saw an overall data reduction of 57 percent.