Other SBC drawbacks include those presented by any need to handle technologies such as high-bit-rate audio/video, high-end imaging, and 3-D modeling. Technologies that will make these applications work well in SBC environments exist and are maturing, but haven't developed to the point that the "full desktop experience" can be delivered to any type of user without consuming significant amounts of bandwidth.
Distributed file systems
Distributed file systems are file systems that are constructed to present a single file and folder hierarchy in multiple physical locations at the same time. The most robust of these solutions are commonly used in grid computing environments where very large numbers of geographically diverse computing nodes must share a common storage environment simultaneously. But most of these option target specialized data.
The challenges in engineering a system like this are significant. Most importantly, the system has to be able to maintain file locks across the entire organization regardless of location. That is, if you are editing a document in Chicago, the storage resources presenting that same storage hierarchy in Los Angeles have to know to prevent users there from modifying the file at the same time you are. This is the most common downfall of do-it-yourself attempts at site-to-site file replication for use in collaborative environments.
In addition, the system should be able to move storage to where it is used most frequently to decrease inter-site replication loads. Blindly replicating huge amounts of data to remote sites that won't use it burns the very bandwidth you're trying to save as well as requiring significant storage hardware cost duplication.
A very common, yet incomplete example of this kind of system can be found in Microsoft's Distributed File System (DFS) found in Windows Server 2003 R2 and Server 2008. This version of DFS builds on previous versions found in Server 2000 and 2003 in that it offers native file replication as well as a unified, transparent file hierarchy. With DFS, you can present an entire organization's file sharing tree as a single hierarchy, regardless of where the data is actually stored. You can also configure sections of that storage to be replicated to the sites that are likely to use them. However, one thing that Microsoft's DFS doesn't do is file locking -- again leading to the same concurrent access issues found in generic file replication. DFS replication can be a great answer for data that is only used by a single user at a time or for read-only data, but not for collaborative data.
A broad range of WAN acceleration devices that have arrived on the market within the past few years. These options include products such as Cisco's WAAS, Citrix's Branch Repeater (previously WANScaler), and Riverbed's Steelhead. These devices and many others like them all have different strengths and weaknesses that make them better for some tasks and worse for others, but they do share two basic concepts.
The first is network protocol acceleration. This is an area that has been inhabited by many a snake oil salesman in the past and has gotten a bad name in some circles. However, if done correctly, there are a lot of optimizations that can be made to various types of network traffic to allow the available network bandwidth to be used more efficiently. The goal is usually to tweak the basics of the IP traffic crossing a WAN to allow it to move across more smoothly and decrease congestion. When this is done properly, circuits can be driven nearly to 100 percent utilization without introducing congestion.