Steelhead Mobile or Steelhead Appliance: Which is right for your branch office?

Introduction: Options for accelerating branch office traffic

As wide-area data services (WDS) has matured as a technology, organizations have found that the acceleration benefits are so impactful on their businesses that they are looking for ways to extend acceleration to every employee, regardless of location. The most advanced WDS vendors have enabled both an easy-to-use appliance form factor for branch offices as well as software that can be installed on a laptop or desktop.

With today's WDS technology, there is a choice up-front that customers typically make: Do you want to use an appliance in the branch office, or install mobile software on branch employees' laptops and desktops?

While the choice between these two approaches is not cut-and dried, there are a number of guidelines that can help enterprises make the right choice for their business. This paper is designed to help enterprises decide between using Riverbed Steelhead appliances and Riverbed Steelhead Mobile software in the branch offer. The paper will start by briefly reviewing the architecture underlying both products, and then provide an in-depth analysis of the different considerations that will impact the appliance vs. software decision.

Both Steelhead appliances and Steelhead Mobile software are based on the Riverbed Optimization System (RiOS). Unlike other vendors who have attempted to develop competitive mobile software, Riverbed is uniquely positioned to support heterogeneous deployments because both products are based on the same software code. Other vendors have tried to 'bolt-and-glue' different technologies together, sometimes through acquisitions, or by even reselling stand-alone OEM products. With Riverbed, performance and ease-of-use can be consistently delivered across all Steelhead products, because they share the same software optimization system.

RiOS was designed using an approach that combines the benefits of TCP optimization, application acceleration, and caching/data reduction techniques, but the RiOS approach does not contain the architectural limitations that these approaches possess as stand-alone optimization methodologies. This architecture allows RiOS to provide the highest performance increase possible to a broad range of applications without requiring changes to existing infrastructure.

In order to accomplish this, RiOS is built as a transparent TCP proxy. During TCP connection setup with Riverbed Steelhead appliances, RiOS replaces the original single end-to-end TCP connection with three back-to-back TCP connections. The TCP proxy connections are established in a one-to-one ratio with no encapsulation or tunnel configuration. The two "outer" connections seen by the client or server look the same as the original connections, while the "inner" connection is invisible to client and server, and allows RiOS to perform a variety of performance improvements for transmissions across the wide area network (WAN). This design allows RiOS-powered products to optimize transfers across the WAN with no disruption or reconfiguration of clients, servers, or routers.

Figure-1: RiOS creates a new TCP sessions across the WAN, which allows it to optimize WAN transfers with no changes to existing infrastructure.

With the Steelhead Mobile client, RiOS acts as the acceleration endpoint while running on the remote computing device. In this scenario, RiOS replaces the original single end-to-end TCP connection with two back-to-back TCP connections. The server-side connection appears the same as its original connections, while the RiOS optimized connection accelerates traffic over the WAN directly from the remote computing device.

Figure 2: RiOS optimizes TCP connections over the WAN directly from the remote user's computer

Steelhead Mobile Video - Episode 1

Steelhead Mobile Video - Episode 2

Steelhead Mobile Video - Episode 3

There are a number of characteristics that will define whether an appliance or mobile software is the right choice for your branches. Of course you may decide on a different approach for different offices; with Riverbed you can freely mix appliances and mobile software. And in some cases, you may decide that you'd like both solutions available for branch employees.

Here are some basic rules that can guide your decision making:

1. If you have mobile workers who are strictly out-of-the-office, Steelhead Mobile is absolutely the right choice for these employees.
2. If you have offices of 5 - 10 people or more, a Steelhead appliance will be the right choice for cost-effectiveness and performance. Steelhead Mobile may still be considered if these employees are out of the office for a significant amount of time.
3. If you have a small office that doesn't meet those criteria, consider the characteristics below to determine the right choice for your offices.

Mobility Considerations

The most obvious consideration is the level of mobility of your branch office workplace. There may be many situations where offices are used for road warriors who need a temporary home. Examples include sales representatives, consultants or field engineers. They may only be in the office once a week, possibly less. They will most certainly need acceleration when they are on the move, so Steelhead Mobile is a good choice.

If these employees are rarely in the office, and the office population itself is uncertain from day-to-day, it might not be worthwhile to additionally invest in an appliance for that office. The two caveats to this approach are (1) if there are a consistent number of employees in the office regularly who are collaborating over the WAN on projects, or (2) where additional features of the appliance are required for branch operations. The next two sections outline these benefits.

Finally, enterprises might also consider accelerating traffic over wireless LANs (WLANs). For many companies, mobility might be partially defined by being able to move around a campus and have connectivity while being untethered. Typically WLANs can add 15 to 30 milliseconds of additional latency and have less bandwidth than wired connections. These restrictions may reduce performance of local applications and further reduce the performance of remote applications. While using a Steelhead appliance in the branch office will help eliminate the performance constraints of remote applications, it will not overcome the latency or bandwidth constraints of the WLAN for either local or remote applications. That may be sufficient for your enterprise. Alternatively, Steelhead Mobile can be deployed to your end users' computers and provide acceleration over the WLAN.

Collaboration Considerations

One of the key differences in using the Steelhead appliance versus Steelhead Mobile is the sharing of the Steelhead data store. Recall that Steelhead products perform data reduction by storing byte-level segments of previously-sent data in their hard drives (or in the case of Mobile, its portion of the laptop or desktop hard drive). It then can check against that data for future transactions and limit the amount of new data required to be sent across the WAN.

With the appliance, the data store consists of data segments that cover all users in the office who are accessing data over the WAN. With Mobile, the data store only represents data that the particular machine has sent across the WAN before.

The implication is that, under normal circumstances, appliances may show better data reduction results. And if many of your users in a branch are typically collaborating on the same material, this might become a significant difference. Moreover, if these users are trying to collaborate in real-time over the WAN on the same project, the overall experience might be better for them while connected through a Steelhead appliance.

Feature Availability & Performance Considerations

Steelhead appliances and Steelhead Mobile are based on the same code, making it easy to use both products in the same network. But feature availability varies from one product to the other. And while both products use the RiOS architecture to provide acceleration to all applications that run over TCP, Steelhead appliances running RiOS 4.1 have more features for acceleration than Steelhead Mobile 1.0. These differences will change over time as both products continue to evolve and add more acceleration features.

The table below shows the difference in Application Streamlining modules between the Steelhead appliance and Steelhead Mobile.

Table 1. Application Streamlining feature comparison of Steelhead appliance running RiOS 4.1 versus Steelhead Mobile 1.0

As a result, application acceleration performance will vary from Mobile client to appliance. All TCP-based applications will see data streamlining and transport streamlining benefits from both products, but if the offices have a key application that can dramatically benefit from a particular application streamlining module present in the appliance, that should be a major consideration for you.

There is one other major factor to consider in the performance arena: computing resources. Steelhead appliances have 100% of the resources on a particular device to perform acceleration. CPU, memory, and disk are all devoted to this primary purpose. But Steelhead Mobile is designed to play well with all applications and services running on an individual's machine. If a user's laptop is loaded down with applications that are utilizing the majority of CPU, memory, and disk resources, Steelhead Mobile will back off, consuming fewer system resources and potentially providing less acceleration benefit, so that the applications continue to perform as well as possible.

Also, Steelhead appliances have additional functionality that may be useful for a branch office. Those features include:

• Quality-of-service
• SSL acceleration that maintains the preferred trust model
• MX-TCP and HS-TCP for high bandwidth, high latency connections
• Proxy File Services for disconnected operations
• Local print serving capabilities

If these features are essential for your branch office, you should consider using the appliance and supplementing your mobile users with Steelhead Mobile.

Technical Considerations

There are a number of technical scenarios in which just one of these products would be the only option to provide acceleration to end users. While most of these scenarios are not hard and fast rules, they may be practices your enterprise has adopted:

• Users in the branch connect via a VPN client on the machine. In this case data is scrambled by the client's VPN before it would ever get to the branch Steelhead appliance, and the appliance could provide no benefit. But Steelhead Mobile software, on the users' machine, would optimize the traffic before it is encrypted by the VPN client.
• An infrastructure-free branch. If certain branches are required to have no additional physical devices, then Steelhead Mobile is the clear choice.
• Issue of additional software. If, on the other hand, your IT team's goal is to minimize software deployed on the end users' PCs, the Steelhead appliance is a better choice for your organization.

Cost considerations

While both the Steelhead appliance and Steelhead mobile are priced for high ROI and quick payback, they do have different pricing models. These pricing models could affect your choice of product for the branch office. The Steelhead appliance is priced on bandwidth and concurrent TCP connections. The entry level price for a Steelhead appliance model 100 is $3,495.

Steelhead Mobile is priced on concurrent licenses; essentially there is a 'pool' of licenses which users can tap into as they log into the system. Steelhead Mobile requires a Steelhead Mobile Controller; it starts at $12,995 for 30 concurrent licenses. One concurrent license is usually able to serve three to five mobile users.

If your organization is looking to support just one or two branch offices with very few users (generally less than 5), the Steelhead appliance might be more cost-effective. If, on the other hand, you have either many small branch offices or a mix of small branch offices and mobile workers, Steelhead Mobile could be a more cost-effective solution for you.

Conclusion: Choosing the right product for your business

The combination of Steelhead appliance and Steelhead Mobile software provides a very powerful solution for accelerating your business in the data center, branch office, and out in the field for mobile workers. Your choice of whether to equip your branch office users with an appliance or with Mobile, or potentially with both products, depends on a combination of cost, technical needs, user considerations, and administrative considerations.

Want more info about Steelhead Mobile or our services?

Simply complete the form below and we will provide you with more detailed info.