XMPP rises to face SIMPLE standard

With the lure of presence-aware applications and systems dangling before them, competitors are warming up for a heated race to establish an industry standard protocol for presence awareness and instant messaging interoperability.

Lines are drawn between two protocols currently working their way through the Internet Engineering Task Force (IETF) standards body: the SIP (Session Initiation Protocol)-based SIMPLE (SIP for Instant Messaging and Presence Leveraging Extensions) and the open-source, XML-based protocol XMPP (eXtensible Messaging and Presence Protocol). Vendors are placing bets, hoping to choose the correct side of the market's eventual shakeout.

Whereas Microsoft and IBM have thrown their weight behind SIMPLE, a groundswell of support is rising behind XMPP, as Hewlett-Packard, Intel, Hitachi, Sony, and others invest in the technology.

Intel's Wireless Communications and Computing Group chose XMPP-based IM vendor Jabber last month. HP plans to deepen its XMPP support with a forthcoming distribution and systems integration deal with Denver-based Jabber.

Often referred to as the Linux of IM, XMPP was developed in the open-source community during the late 1990s and then submitted to the IETF for standards consideration. This month XMPP reached working group final-call status within the IETF. The protocol is within months of reaching final ratification as an IM and presence awareness standard, according to PeterSaint-Andre, executive director of the Jabber Software Foundation, the Jabber-sponsored, open-source organization fostering XMPP's development.

For its part, SIMPLE is also progressing through the IETF but is expected to be completed after XMPP. With weighty stamps of approval from both Microsoft and IBM, SIMPLE is perceived by many to be the clear winner in the IM and presence standards race.

But some observers have noted technical issues with the protocol that have caused some early users to seek alternatives. SIMPLE is a set of IM-related extensions for the IP-based signaling protocol SIP, originally designed to enable IP telephony and other direct Internet connections. Critics charge that because it uses a signaling protocol for data exchange, SIP is ill-suited for IM and presence functionality.

"I put no faith in SIP and SIMPLE as the basis for IM interoperability standards," said analyst Rob Batchelder, president of Relevance, a strategy consulting group in Trumbull, Conn. SIP was intended for applications such as VoIP, but there is "now an effort to take SIP and use it to provide basic enabling capabilities for global IM interoperability. The problem is that SIP was not intended to be that."

The SIMPLE extensions that address IM have not been clearly thought out, Batchelder added. The problem with SIMPLE, he said, is that the approach of using standards-based gateways between IM systems is architecturally unsound, because they add delays and introduce messaging transmission problems.