Microsoft released Application Request Routing Version 2.5 for IIS 7, both in 32-bit and 64-bit flavors, making it available through the Web Platform Installer (WebPI).
Microsoft Application Request Routing (ARR) for IIS 7 is a proxy-based routing module that forwards HTTP requests to application servers based on HTTP headers, server variables, and load balance algorithms.ARR version 2.5 is an incremental release that includes all of the features from version 1 and 2.
ARR version 2.5 improves the performance and scalability of disk caching features in ARR.
According to the software giant's Won Yoo, ARR 2.5 for IIS 7 is capable of delivering a boost in performance to ARR. At the same time, in addition to the speed increase, customers will also be able to take advantage of enhanced scalability capabilities for ARR around disk caching scenarios.
Optimization word was done to kick up a notch memory usage and disk caching, but also to resolve issues related to Application Request Routing server throughput decrease following the switching on of the disk cache feature.
With ARRv2.5, Microsoft's focus was on taking performance and scalability to the next level and delivering latency improvements. However, there is also a functional evolution between ARRv2.1 and ARRv2.5.
"One functional change that is worth mentioning is the ability to set the client affinity cookie on the main domain name. This particularly interesting if the site has multiple sub-domains, such as images.contoso.com, members.contoso.com and so on" Yoo stated.
"On such sites, in order to maintain client affinity across sub-domains, the client affinity can be set on the main domain, .contoso.com."