Web server administrators with large Web farms are familiar with Cisco's wildly popular LocalDirector product. LocalDirector sits in front of your Web server and provides load balancing across the server farm to ensure content is always available. LocalDirector has become a staple of many large Web server farms.
Earlier this summer in one of NASDAQ's blockbuster deals, Cisco acquired ArrowPoint Communications, which makes a product that goes even further than LocalDirector. Now that Cisco has folded in ArrowPoint, the result of the marriage is beginning to show. Meet Cisco's 11000-series Content Services Switches (CSS). These switches do much more than LocalDirector.
To understand the function of CSS, think of the switches as intelligent proxy servers. Most networking components work in the lower layers (network and below) of the Open System Interconnection (OSI) model, leaving the higher layers to the server OS and applications. CSS works in these higher layers (i.e., Session, Presentation, and Application layers) as well, evaluating the Web request that the client browser sends. The CSS proxies the Web request on behalf of the Web client and directs it to the appropriate server, a decision the CSS makes based on server availability, load, and user's proximity to your Web servers. If one of your remote Web servers offers better round-trip times to the client, CSS sends HTML error 302 and redirects the client to the faster server.
CSS also offers some security protection. The switches are intelligent enough to detect and discard SYN and Ping floods, "smurf" attacks, and other known Denial of Service (DoS) attacks. CSS can also load balance Web traffic across multiple firewalls for redundancy.
If these features aren't enough to make you salivate, check out the content-replication features. You can use CSS for content staging and replication, which gives you options for content management. Additional features let CSS dynamically replicate "hot" content to another Web server to help you pull through those tough peaks in server traffic. Click here to learn more about Cisco's CSS.
