AFE accelerates applications.

Last year, TriNet, a leading provider of human resources services, decided to evaluate its existing infrastructure and weigh possible options to optimize and accelerate its software solutions. Based in the San Francisco Bay area, TriNet provides its customers with complete access to their own data through a secure portal called HR Passport, available via any Web browser. With HR Passport, authorized users can make benefits funding decisions, hire and terminate staff, administer promotions and status changes, submit payroll hours and access company reports and analytics.

The TriNet IT department had already decided to deploy an updated version of the core HR Passport PeopleSoft application in 2005 but was concerned about user response times, especially during open enrollment events. Rich Goddu, TriNet's director of networks and systems, began evaluating possible solutions that would allow him to accelerate application response without making wholesale changes to his existing infrastructure.

He discovered a relatively new family of products called application front ends (AFEs), designed to offload processor-intensive tasks from servers in order to maximize server resources. Like traditional load balancers, an AFE resides logically between the Internet and the Web application.

In addition to traditional load-balancing duties, AFEs typically offer such features as TCP termination, offload/multiplexing, SSL acceleration, compression and protection from malicious distributed denial-of-service (DDoS) attacks, as well as protection against the performance degradation caused by flash crowd events.

A flash crowd event occurs when a sudden burst of user activity occurs on a site that places demands on the system that were not anticipated by the original system architects. TriNet regularly experienced flash crowd events during benefit open enrollment periods, when large numbers of clients attempted to access processor-intensive applications to modify benefit packages.

Eventually, Goddu tested and chose Crescendo Networks' Maestro AFE, which provides several methods of implementation, enabling it to be installed in virtually any server environment. TriNet wanted to be able to install the device with a single interface without reconfiguring any of its servers or peripheral networking devices.

The AFE was configured with an IP address for the management Ethernet interface, and an IP address for the interface connected to the same switch as TriNet's servers. As a large number of users approach the TriNet portal, Maestro opens a small number of backend TCP connections to each server, and terminates and manages the front-end applications to ensure that the servers receive only the amount of application traffic they can handle comfortably.

TCP offload works by terminating every end-user connection at the AFE, which buffers and analyzes each request and then sends it to the most available server through a managed back-end connection. In this environment, the AFE becomes the client communicating directly to the server over the high-speed LAN fabric. The server processes the user request and responds back to the AFE, which then determines the most efficient way to forward the response back to the end-user.

One of the keys to increasing server scalability is the AFE's ability to "shield" the server from client TCP connections. Instead of managing many TCP connections, each with individual characteristics, the server is now only aware of a small number of persistent, high-speed connections from the AFE. This enables the server resources to be focused on application processing instead of connection or SSL management.

Maestro's compression capability reduces TriNet's bandwidth consumption, and also serves to further reduce end-user response time. The SSL acceleration module offloads the CPU-intensive task of enabling secure connectivity to HR Passport and TriNet's other applications. Management is then simplified by enabling IT staff to manage all SSL certificates in a single device.

Once installed, the solution immediately improved application response time and scalability of the PeopleSoft-Oracle application, Goddu says. The product's ability to utilize all advanced features simultaneously, even at gigabit speeds, enabled TriNet to use only two redundantly deployed AFEs. End-user response time improved by 40% to 50%, bandwidth consumption was reduced by 55%, and the existing application infrastructure demonstrated 3-5 times the scalability of the previous solution, utilizing the same server hardware. Additionally, Goddu needed to provision only eight servers, instead of 25.

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