So I told him about a demo I saw a year or two ago of Microsoft's Office Communications Server and Windows Mobile, showing the ability to automatically route or suppress messages based on status. That functionality was all tied into calendaring. When you're in a meeting, messages and calls are suppressed. The CIO jumped up: "I want that. I don't care about the rest of it. I want that!"
This is the promise of presence as part of unified communications software, a capability that goes far beyond the status messages in IM software. Presence enables simple but effective automation, telling others if you're available and how you can be reached--via voice, IM, desktop or application sharing, or SMS.
Or it can automate message reception and notification. When coupled with calendaring, presence status can be automatically activated whether you're in a meeting, on the road, or on vacation. Unlike follow-me services that try different numbers to contact you, presence declares your state and how you can be communicated with, allowing the caller to choose the most appropriate methods you've allowed.
Presence is a core component in UC platforms, but it's effectiveness is stunted by limited interoperability among products. The problem stems from one too many standards. The Internet Engineering Task Force's Simple protocol suite relies on the Session Initiation Protocol to transport presence information, and it's being adopted by many UC vendors, including Avaya, Cisco, Nortel, and Siemens. The Open Mobile Alliance, an industry group of vendors and providers, leverages Simple to communicate presence to and from mobile devices. However, a second presence protocol--XMPP, which is aimed at instant messaging--is also an IETF standards-track protocol, having grown out of the Jabber protocol. The two protocols don't interoperate, so bridging them to share presence requires gateways such as the IBM Lotus Sametime Gateway.
Within a single product suite, presence generally works well. Both Simple and XMPP can be extended so vendors can adapt them to their needs while still providing basic interoperation. But two products using the same protocol won't necessarily integrate easily, since both protocols are extensible by vendors and the extensions have to be interpreted.
Basic interoperation is limited to showing whether a person is available. The standards community must agree on common attributes beyond "available" and "not available" to ensure interoperation.
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