Evaluating Expand Networks accelerators for WAN optimization

Expand Networks' accelerators help WAN optimization by supporting branch office server consolidation, server-based computing and virtualization technologies, as well as low-bandwidth, high-latency links.

In 2009, WAN optimization vendor Expand Networks adopted the marketing slogan of "Optimizing WANs for branch office IT consolidation and virtualization." Living up to that slogan, Expand now focuses on supporting branch office server consolidation, server-based computing (SBC) and virtualization technologies such as virtual desktop infrastructure (VDI), as well as low bandwidth, high-latency links like those typically associated with...

satellite communications. The company has established the objective to be one of the top two providers of optimization in these areas. Expand has drawn notice, and Riverbed is said to be negotiating an acquisition.

Expand differentiates itself in part based on the relationship it has with networking and satellite providers such as Inmarsat and Clear Channel Satellite. The company has an affiliation with 3Com (which is being acquired by HP), Quest, Microsoft, NetApp, DoubleTake, Vision Solutions and Oracle. Expand claims to have a strong relationship with VMware and also says it's the only vendor to provide a complete virtual platform that can accelerate interactive IP and UDP protocols for both SBC and VDI implementations. It offers a Mobile Accelerator (MACC) that it hopes to embed into thin clients, branch office boxes and mobile handheld devices.

According to the company, the Expand solution is set apart from other products in the market because it:

  • Transparently integrates into existing IT infrastructures without network hardware upgrades.
  • Has a Layer 7 quality of service (QoS) engine that provides in-depth monitoring and management. This includes the ability to prioritize traffic within Remote Desktop Protocol (RDP) and Citrix ICA streams on a single unified platform.
  • Supports a virtual server that provides full file server support and services for consolidation and server replacement without the need of additional licenses or applications.

When queried by the author, Expand stated, "Our virtual appliance uniquely provides high availability and warm cache functionality at no cost to the customer."

Important facts about Expand Networks' accelerators

Expand's WAN optimization platform is Linux based and uses the proprietary Accelerator Operating System (AOS). According to Expand, both its physical and virtual appliances, as well as the virtual mobile client, run on a single version of AOS. The AOS QoS engine provides an infrastructure for monitoring, application classification and application shaping. Expand's QoS and compression technologies support all IP protocols: TCP, UDP, ICMP and GRE. The QoS engine classifies traffic according to source and destination IP addresses; source and destination TCP/UDP ports; IP protocol (for non-TCP/UDP traffic); type of service (ToS) and DiffServ values; and Layer 7 information.

Expand says that 600 Layer 3 and 4 applications and 25 Layer 7 applications are discovered by default, and that its products can implement outbound and inbound control on the traffic based on prioritization (real-time, high, medium, low, discard), guaranteed bandwidth for critical applications, bandwidth limits by application and by flow, temporary burst capability, and DiffServ and ToS/CoS coloring.

AOS provides four main technologies to reduce congestion. They are:

  • Byte-level caching: The algorithm that Expand uses provides cross-session caching, which Expand says can detect and optimize very small repetitive patterns. The algorithm works in memory and optimizes any IP traffic, including real-time traffic. The algorithm includes data (payload) and header compression optimization.
  • Wide area file services (WAFS): This functionality supports file-caching and delta compression (a.k.a., deduplication) of files.
  • HTTP/FTP caching: The AOS platform provides HTTP and FTP caching to serve frequently accessed objects without traversing the WAN.
  • DNS caching: AOS provides DNS caching for immediate name resolution.

Expand's TCP acceleration is based on SCPS (Space Communications Protocol Standards), which was developed by NASA and the Department of Defense for high-latency communication. SCPS optimizes TCP with three-way hand shaking, window sizing, fast-start algorithms and congestion avoidance algorithms such as Vegas and Reno.

When it comes to optimizing application protocols, Expand has a Common Internet File System (CIFS) acceleration component that eliminates the chattiness of CIFS. The company also claims to provide specific application plug-ins for applications such as:

  • Disaster recovery and backup applications (such as Doubletake, Snapmirror and NetApp)
  • ERP applications (such as SAP, Oracle and BAAN)
  • Document management systems (such as SharePoint and Documentum)
  • Mail applications (such as Exchange and Lotus Notes).

For more, read all the sections in our guide:

About the author:
Dr. Jim Metzler, principal at Ashton Metzler and Associates, is a widely recognized authority on network technology and its business applications. In more than 28 years of experience, Jim has helped numerous vendors refine product and service strategies and has helped enterprises evolve network infrastructures. He has directed and conducted market research at a major industry analyst firm and run a consulting firm. Jim holds a Ph.D. in numerical analysis from Boston University. He has is co-author of the book Layer 3 Switching: A Guide for IT Professionals (Prentice Hall).

This was first published in February 2010

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