In the last couple of newsletters, we discussed the movement to consolidate servers into centralized data centers. We also discussed the problems that can result from running Common Internet File System-based applications such as Microsoft Word, Excel and PowerPoint over a WAN. In particular, we discussed how the CIFS protocol breaks large files into smaller blocks and only sends one block at a time. As a result, a user in a branch office who is attempting to open a large file that is stored in a central data center may have to wait an unacceptable amount of time for that file to open.

One solution to this problem that has garnered a lot of media attention in the last year or so is wide-area file systems (WAFS). WAFS are focused on reducing the delay that is associated with taking applications that are based on LAN protocols such as CIFS or Network File System (NFS), and running them over a WAN.

Current WAFS products are sophisticated and becoming increasingly more so. These products typically implement myriad technologies such as caching and pipelining, as well as security functionality such as encryption. Some current products also implement technology that anticipates and delivers the data the user will require before the user even requests it. WAFS vendors are talking about adding QoS capabilities as well as support for protocols other than CIFS and NFS, such as FTP, secure FTP, TFTP, and HTTP.

There is no doubt that a WAFS solution is a good short-term answer for many companies. However, it is less obvious that WAFS will be a good long-term solution. One of the reasons is because WAFS solutions require implementing yet another specialized appliance in a branch office. WAFS will accelerate the performance of certain applications running over certain protocols. A highly specialized WAFS appliance are required to sit in the branch office next to numerous other applications, each of which is also performing some highly specialized task in order to make applications run better over the WAN.

Few companies want their branch offices littered with such appliances. Future newsletters will give our insight into how this market is likely to evolve. In the meantime, the next newsletter will present another reason why WAFS may not be a long-term solution for many companies.

Steve Taylor is president of Distributed Networking Associates and publisher/editor-in-chief of Webtorials. Jim Metzler is vice president of Ashton, Metzler & Associates.