dyork also wrote:

Yet another reason for investing SIP vs. H.323 is the fact that I understand Microsoft's next version of NetMeeting will use SIP as its underlying protocol. I was told that Windows XP would ship with a "SIP-phone" included, although it is hard to understand if that is just another part of Microsoft's "Windows Messenger". In any event, SIP definitely does seem to be on the rise.

Hmmmnnn... now that's an interesting piece of news. I don't keep up as well as I should with Microsoft's plans, so I was unaware of this wrinkle.

In this case, as in so many others, MS is following the industry rather than leading it. I would be shocked if it were not using a broken version of SIP that makes compatibility difficult. However, I think this time the strategy will lose. Vendors have really taken the high road with SIP; they've worked hard to ensure compatibility at events like the SIP Bake- Offs (now renamed to SIP Interoperability Test Events after threats by Pillsbury. Is this country insane?)

When SIP vendors find a part of the standard that needs changing or clarification, it goes into an additional IETF document. (So far they've shied away from modifying the original RFC.) In general, vendors will bend over backwards to interoperate even with other people's broken stacks. I don't think Microsoft can break compatibility even if it tries.

Given that, it would be nice to have a SIP phone on most Windows desktops. It would certainly help increase the popularity of any Vocal service, commercial or otherwise.

Dang... maybe I'll have to break down and buy a copy of Windows. (I was thinking about doing that anyway so I could play with writing Unix-to-Windows-portable Perl programs.)