Better for the Branch — Which Architecture is Right for Your Remote Sites?

An IT manager recently pinged me about our approach to branch offices. He was considering Riverbed’s SteelFusion (formerly Granite) and wanted to evaluate a comparable solution from Silver Peak. It’s a common question and one that underscores the enormous agility, cost, and functionality of the Silver Peak approach.

So I decided to work up a comparison based on publicly-available reference architectures and pricing. I used Riverbed’s reference architecture (retrieved on April 07, 2014) and publicly-available Riverbed pricing, such as can be found here. I then compared that architecture with Silver Peak running on a Dell VRTX, using information and pricing from a document provided by Dell, “Comparing Performance and Cost: Dell PowerEdge VRTX vs. Legacy Hardware Solutions,” by Principled Technologies (

I’m sure you folks will have a lot to add and I encourage you to do so in the comments below. Oh, just in case you don’t want to read all 1200+ words of this post:

Silver Peak + VRTX outperforms Riverbed SteelFusion and costs half as much.

I know, I know it’s from us, but work through the data yourself and I think you’ll draw the same conclusion.

The Scenario

SteelFusion provides compute, storage, data replication, and WAN optimization and is available in stand-alone appliances as well as add-ons to the Steelhead EX. Riverbed’s reference architecture calls for the deployment of redundant EX1260-VHs in the remote office, and Steelhead CX and redundant SteelFusion core appliances in the data center. Branch file and application services run on the EXs, replicating data back to the data center (see Figure 1).

Figure 1: The Riverbed reference architecture for the branch introduces numerous problems for today’s organizations. (Image: “Riverbed Granite Reference Architecture”, Riverbed Technologies)

Figure 1: The Riverbed reference architecture for the branch introduces numerous problems for today’s organizations. (Image: “Riverbed SteelFusion Reference Architecture”, Riverbed Technologies)

Silver Peak is very different. We separate the software and the hardware layers, and partner with other best-of-breed providers. This way, IT can use its existing tools, software packages, and preferred hardware to address IT requirements. Silver Peak has been deployed on individual servers, Cisco routers, High Availability (HA) clusters, and even on desktop PCs. The compute and storage functionality would be provided by a different vendor.

I chose to replace the Steelhead EX appliances at the branch with a Dell VRTX, which combines compute, storage, and networking functions into a single, integrated unit. A Silver Peak VX-5000 would run on the VRTX and communicate with a VX-8000 in the data center running in an HA cluster. Although I added two Dell servers to the data centers for calculation purposes, in reality additional hardware would likely be unnecessary, as there is often a surplus of compute capacity. Branch survivability is provided through dual-homed connections to different WANs. Storage is assumed to be the same; data protection and replication would be provided by a partner, such as Dell or VMware. I chose to keep things interesting and use Zerto (see Figure 2).

Figure 2: Silver Peak approach eliminates unnecessary hardware, lowering costs, and leverages best-of-breed software and hardware for maximum value.

Figure 2: Silver Peak approach eliminates unnecessary hardware, lowering costs, and leverages best-of-breed software and hardware for maximum value.

Eliminating Riverbed’s proprietary hardware dramatically lowers the cost of the overall solution. The Silver Peak Branch Office Architecture is less than half of the cost of Riverbed to build out and maintain. As the number of branches grow, so does this cost difference.

Figure 3  By working with partners, Silver Peak is able to deliver a branch office solution at the fraction of the cost of Riverbed Granite.

Figure 3: By working with partners, Silver Peak is able to deliver a branch office solution at the fraction of the cost of Riverbed SteelFusion.

Note that these calculations do not factor costs assumed to be consistent between the two scenarios, such as a switching, routing and more. VRTX pricing is based on “Comparing performance and cost: Dell PowerEdge VRTX vs. legacy hardware solution,” Principled Technologies (, a paper recommended by Dell.


Riverbed SteelFusion’s underlying hardware is not only expensive, but also constrained as server nodes. Only six cores can run in the EX; whereas a Dell VRTX can reach 16 cores per compute node, with a maximum of four compute nodes. The EX is limited to 64 GB of usable memory; each VRTX compute node scales to 768 GB. As for storage, SteelFusion is limited to 20 TB of HDD and 400 GB of SDD. VRTX scales to 48 TB of internal storage (see table: “Configuration Detail: SteelFusion vs. VRTX”).

Configuration Detail: SteelFusion vs. VRTX
CPUs Cores per CPU Memory Disk
Riverbed Steelhead EX1260 (4TB) VH 1 6 10 GB2 5 TB HD; 320 GB SDD
Dell VRTX1 4 6 32 GB 5 TB HDD

1For further details and pricing information on the Dell VRTX configuration see “Comparing performance and cost: Dell PowerEdge VRTX vs. legacy hardware solution,” Principled Technologies (
2Reflects memory available for VSP and VMware; system memory will be greater.

To compound matters, the use of proprietary appliances prevents organizations from enjoying the cost benefits of virtualization. Riverbed recommends deploying two EX1260s in the branch for a total list price of $134,790, including all software licenses. By contrast, the cited VRTX configuration already includes redundant blades configured as an HA cluster. One instance of VX-5000 is needed in the branch — not two — to provide HA. The same is true in the data center.

Aside from the numerous problems of Riverbed’s proxy-based architecture, SteelFusion also faces WAN challenges in protecting the branch. Data is not encrypted by default in most Riverbed appliances, exposing the organization to data theft and eavesdropping. Enabling IPSec encryption dramatically limits scalability, already a problem for Riverbed, and does not protect the numerous protocols Riverbed passes-through. Silver Peak’s Accelerated IPSec protects all site-to-site traffic, outperforming traditional IPSec solutions without any degradation in optimization performance or scalability and at no additional cost.

Site availability will also suffer. Riverbed’s path selection technology is rudimentary — only detecting line failure after the network is lost. Increased rates of latency or packet loss preceding an event go undetected by SteelFusion. The result: users may see their application performance decrease, or drop altogether while data is switched to an alternate path.  Silver Peak’s Dynamic Path Control technology addresses this problem.

What’s also often missed with proprietary branch appliances are the constraints dictated in the core design of the network. With Silver Peak, organizations can choose whatever compute platform they want in the data center. In fact, often organizations will need no new hardware, leveraging the existing surplus of compute capacity found in most data centers. SteelFusion requires additional proprietary hardware in the data center, raising costs, and adding complexity as IT must weigh numerous other considerations such as rack space availability and power.

Riverbed acknowledges the importance of redundancy at both the branch office and the data center, which is why it doubles the EX and SteelFusion appliances in either location of the reference architecture. But the Riverbed architecture does not go far enough, introducing a single point of failure at the most critical juncture: the CX. The data center is expected to connect to the WAN with an individual CX not redundant CXs. Perhaps that’s to reduce the reference architecture’s overall price — one CX lists for $129,995, nearly equal to the cost of two EX branch appliances.

Operational Costs

The problems with SteelFusion, though, are not limited to higher capital costs. Operationally, the Riverbed architecture forces IT to spend more time tuning the proxy architecture, patching software, updating application proxies, and more. Deployment, particularly of non-TCP applications, is notoriously difficult. Introductions of new applications or new versions of existing applications also require updating Riverbed’s acceleration architecture, complicating rollouts and limiting corporate agility.

SteelFusion’s proprietary hardware minimizes the benefits organizations can realize from the continual improvements in server design. End-of-life actions force organizations to upgrade their hardware configuration unwillingly. Sparing is more expensive as organizations are limited to the choices Riverbed offers, marked up 30 percent or more when compared against comparable components available on the open market.

Customers are locked into the limited set of applications and services provided by Riverbed, and software integration is no boon. The innovations in virtualization and adoption of hypervisor tools improve the management of any infrastructure.

Riverbed appliances also face significant scaling problems, supporting a very limited number of concurrent sessions. As such, organizations are forced to upgrade their appliances long before they consume their WAN bandwidth. After five years, for example, Riverbed appliances often need to be replaced, making their total cost 70 percent more expensive than Silver Peak.

By contrast, Silver Peak software never forces customers into an upgrade, providing a practically unlimited number of concurrent sessions. Furthermore, where an upgrade is required, customers simply pay the difference to the next software appliance. Riverbed imposes a five to 15 percent upgrade penalty.

Bottom Line

An integrated appliance addresses a real concern in the branch, but the advancements in server design and virtualization make a proprietary appliance, such as SteelFusion, often outdated. Riverbed talks about projecting block-storage out to the branch and I am sure there are definite use cases for that functionality. But in the overwhelming number of instances, combining best-of-breed tools — such as a Dell VRTX, Zerto replication software, and Silver Peak — will avoid the limitations of SteelFusion and provide IT with an easy-to-deploy and affordable branch office appliance.


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