The T|X 2650 is built on a custom OS and is designed to alleviate the problems associated with servicing low-bandwidth clients. For example, Apache Web servers deployed on low-end hardware--like the PIII 600-MHz machines in our Real-World Labs® in Green Bay, Wis.--can maintain only a limited number of connections. If most of your visitors are connected via a 56-Kbps or slower modem, the SendQs available to Apache fill up quickly but empty out slowly, limiting the number of visitors the server can accommodate.
I tested the T|X 2650 in our labs, using Spirent WebAvalanche to emulate clients accessing a single Apache Web server at 33.6 Kbps. Without the T|X, the server attended to 55 clients per second, each requesting a single HTML file with three embedded images for a total of 24 KB. With the T|X, the Web server successfully served 330 clients, and the total time to retrieve the entire page dropped from 17,501 ms to 9,163 ms.
The T|X 2650 offers some basic Layer 4 load-balancing capabilities. Up to 128 clusters (pools) can be configured with up to 8,192 servers. The GUI allows configuration of up to 32 servers per cluster; additional servers in a cluster must be configured on the CLI. The device supports persistence via cookies but does not offer other configurable choices for the load-balancing functionality.
The T|X 2650 has a "busy redirection" option that redirects a browser to a specific URL when the device is too busy to process a request. The URL could try to redirect back to the T|X after a specified amount of time or show special content while the user is waiting for access to the site.