On 10/09/2009 Microsoft announced release of Application Request Routing (ARR) 2.0. More details at http://www.iis.net/extensions/ApplicationRequestRouting.
IIS Application Request Routing (ARR) 2.0 enables Web server administrators, hosting providers, and Content Delivery Networks (CDNs) to increase Web application scalability and reliability through rule-based routing, client and host name affinity, load balancing of HTTP server requests, and distributed disk caching
- HTTP based routing decisions built using rules that examine HTTP request information
- Sophisticated load balancing algorithms to determine appropriate servers to service the HTTP requests
- Health monitoring for live traffic and specific URLs to determine the health of servers with a set of configuration parameters provided to calibrate baseline server health
- Client affinity to direct all requests from a client to a specific server by using cookies.
- Host name affinity to streamline administration for Web servers and to create additional business opportunities.
- Management of multiple server farms to enable pilot management and A/B testing scenarios.
- Management and monitoring of all configuration settings and aggregated runtime statistics through IIS Manager interface.
- Support for Failed Request Tracing Rules
- Disk-based caching
- Cache hierarchy management
- Cache proxy node in CDN/ECN environment
- Caching compressed objects
- Browsing cached contents using IIS Manager
- Removing cached contents by matching URL patterns
- Overriding cache-control directives
- Warming up cache mode
- Intelligent byte-range support
- Intelligent live request support
- Caching while serving responses