Just a quick note: We talked previously about the improved TCP/IP stack in Windows Vista (here and here) but now Ann Bednarz at Network World has taken an in-depth look at what Vista's code changes mean for WAN optimization planning.

Between the updated TCP/IP stack, the new CIFS implementation, and built-in QoS enhancements, there's much to look forward to in Vista, but the main criticism addressed in the article is that the best benefits are only reserved for those who upgrade to Vista on the entire IT infrastructure - with a Vista client and a Longhorn-based server, and required upgraded hardware and may need recoded applications as well.

Additionally, Vista's improvements don't do much for Web-based applications and does not deal with data-reduction based compression - so Vista will not replace the need for a WAN Optimization appliance.