Previously, when we looked at server room components, we focused on storage. First, we looked at NAS and SANs and then at RAID controllers. This week, Hardware Today turns its attention to application delivery server components, which are typically called application switches.
Application switches connect business-critical apps to the network, bolstering performance, security, and availability in the process. This week, we examine the technology and players in this relatively recent addition to the data center.
At their most basic, application switches bolster performance, security, and availability for business-critical applications. Application switches reside where the network and applications intersect. They handle performance problems inherent to integrated software suites, such as those from PeopleSoft, SAP, or Siebel.
Application delivery is a relatively new area of focus that began with load balancers in the mid-1990s. Load balancers were designed to bolster Web site availability. They routed requests by IP address based solely on Level 4 (L4), the TCP/IP level of the network stack.
Today, “The typical application world isn’t getting any better, if anything it’s getting worse, in terms of acknowledging the fact that users do connect in different ways,” Gartner Vice President of Enterprise Communications Mark Fabbi told ServerWatch.
Enter application switches. Application switches don’t just load balance, they also monitor Level 7 (L7), the HTTP portion of the data stack, enabling them to parse traffic based on URI information. For example, the URI “application1.jsp” can be routed to one set of servers, and “application2.jsp” can be routed to another set. Parsing on the L7 stack obviates the need for TCP-level (L4) parsing of HTTP packets.
“This allows companies [to] multiplex HTTP requests on fewer TCP connections when sending them to a server,” Steve Shah, director of product management for NetScaler, told ServerWatch. “The load balancer piece handles the TCP connectivity for L7 traffic and L4 balancing for non-Web traffic,” he said. This technique, called L4-L7 switching, bolsters performance and offloads work from servers, freeing them up for other tasks.
Switch Leaders Focus on Applications
Today’s application switches offer these and a slew of other data optimization techniques. “It’s all about, how do you make the application work better,” Fabbi said.
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Ignoring this functionality has its perils. Fabbi sees load balancer standbys, like Cisco, Nortel, and Foundry, struggling against the more innovative vendors. For these golden-oldies, the burgeoning application delivery space may not currently drive enough sales volume to be tempting. But this is changing. Although Gartner does not yet break out sales figures for the application delivery market, Fabbi has penned a Magic Quadrant, a Gartner-derived matrix that offers a graphical representation of a particular marketplace.