Improvements in Web site performance attributable to the T|X 2200 can range from two times to 20 times (according to Redline), depending on the type of traffic, clients, and whether SSL is in use. Given the cost of bandwidth and of adding additional servers to a load-balanced cluster, the appliance's $19,995 price can be recovered quickly even if the device only doubles the performance of a Web site.
This is, more than usual a case where mileage may vary -- performance increases can differ widely, depending on the types of traffic, how the Web site is constructed, whether SSL is being used, how many users have HTTP-1.1-compatible browsers, and how compressible the data is. In our testing, improvements ranged from a little over two times to more than 10 times.
Redline Networks has an ROI calculator on its Web site at http://www.redlinenetworks.com/p/roi, and will create a custom report on the performance benefits your Web site should see, at http://www.redlinenetworks.com/p/test. The site also has some interesting testimonials from large sites detailing the performance benefits they received.
We received the T|X 2200 model for review. This is the middle model in the T|X series ($9,995 to $24,995). It supports 64 virtual IP addresses and up to 32 servers per virtual IP address, as well as 200 SSL transactions per second, 100 Mbps of throughput, and 50,000 simultaneous connections, in a 1U (1.75") form factor.
Setting up the device is extremely simple. The unit is a single-leg device: Rather than routing traffic, it resides on the same network as the load balancer or Web servers, and it acts as a reverse proxy server. The device has two 10/100 Ethernet ports, but one is a heartbeat connection used only for a second T|X appliance set up as a failover/hot spare device.
Changing the existing network configuration should not be necessary in most cases. All that is required is a virtual IP address for the Web site on the T|X device, and then a to change the DNS entry for the site to the new IP address.
Setting up the appliance requires inputting the basic IP configuration information through a serial terminal connection. The rest of the configuration can be completed via the browser interface, which can be configured to use SSL if desired. The browser interface will not work unless a password is set for the admin account, and the rest of the configuration process consists of entering the IP addresses of the load balancer or Web servers and SSL certificate information if necessary.
In addition, some filters can be set up so that Web servers receive the actual client IP addresses, if necessary, for logging or other uses. The filters support IIS, Apache, and iPlanet Web servers. A custom setting enables the user to create a filter for other Web servers.
The manual that comes with the T|X 2200 is a 44-page basic installation and administration guide. Most users, however, should find it sufficient. The T|X 2200 comes with a one-year limited warranty that includes toll-free technical support and advance replacement for the first 90 days, and return and repair thereafter.
So what does the T|X 2200 actually do? First, it reduces the number of connections that a client uses to access a server. In cases where a normal client accessing a server might create dozens or even hundreds of TCP sessions, the T|X consolidates all the sessions for each client into one, maintaining the session as long as the client is connected.
Second, it determines if the client supports HTTP-1.1-compliant compressed data and compresses the data in real time when appropriate. It can filter out non-renderable data from HTTP traffic. (No small accomplishment considering that according to Redline Networks, non-renderable data can be five to 15 percent of all HTTP transmitted, and compression generally reduces traffic by five to 10 times.) Finally, offloading SSL processing from the server can also provide substantial performance gains for a Web site compared to using the SSL capability of the Web server.
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