In previous WAN newsletters, we described various WAN optimization techniques as well as some of the dynamics of the WAN optimization marketplace. In this newsletter, we will discuss how a company (CitiStreet) used WAN optimization to save money and to comply with regulatory requirements.

CitiStreet is one of the largest global benefits delivery firms in the U.S. It serves more than 10 million participants and administers well over $200 billion of assets. As part of its operations, CitiStreet administers the records of 9 million-plus subscribers.

Within the U.S., CitiStreet has data centers in Quincy, Mass., Jacksonville, Fla., and Somerset, N.J. According to CitiStreet's CIO Barry Strasnick, in order to ensure the highest levels of availability for the company's clients, CitiStreet replicates 6G bytes of customer data on a daily basis. Due to regulatory requirements, this data must be encrypted before it can transit the WAN.

The problem that CitiStreet faced was multi-faceted. Part of the problem was that CitiStreet's daily data replication, which was taking 55 minutes per day, was likely to increase in the time it took as CitiStreet added customers. In addition, its existing approach to encryption consumed a significant amount of CPU cycles on its servers. Finally, if it did not find a way to reduce the amount of time it took to do secure data replication, it would be forced to increase the capacity of the WAN by purchasing additional bandwidth.

According to Strasnick, it is difficult to find a solution that can do a good job of compression and at the same time implement encryption. Strasnick also stated that he was "historically not big on implementing appliances." 

In spite of his historical resistance to implementing appliances, Strasnick deployed a new session layer (Layer 5) technology that combines the functionality of WAN optimization, application acceleration and data encryption in one appliance. The technology employs Layer 4 WAN optimization techniques to maximize the throughput of the network while using Layer 7 application acceleration techniques to speed the data replication. The appliances, which are deployed symmetrically at both ends of the link, also provide data encryption, ensuring regulatory compliance for all data transfers over the WAN. 

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