Andrew Laurence recently posted the following to the caladmin-l mailing list:

While googling a bit today, I found Microsoft's web services API for the Exchange Availability service. If you have Exchange 2010 on both ends, this allows for scheduling across installations/domains.

Since we've often pined for a bridge between Exchange and standards-based calendar environments, might their be a natural fit for developing a bridge to iSchedule? (Insert hand waving about undefined development resources.)

[MS-OXWAVLS]: Availability Web Service Protocol Specification

[MS-OXCICAL]: iCalendar to Appointment Object Conversion Protocol Specification
Is MS-OXWAVLS already used by Zimbra's Exchange Free-Busy Interop?

If not, might this API be used to allow Zimbra users to access Exchange users' free-busy, similar to what I proposed for Zimbra-Zimbra interoperation in Bug 35304?