Transports provide a way for users of XMPP-based (define) instant messaging systems to talk to public networks such as MSN or Yahoo!, but if you've had experience with them you'll realize they are far from ideal.

Registering with a transport - when you find the one you want on a server somewhere on the Internet – can be very far from an intuitive process. And that's usually the easy bit. Once you register you'll get a presence subscribe request from each user on your contact list which you have to confirm manually. These have a habit of staying even if you subsequently unsubscribe from the relevant transport.

It's to address these problems - essentially caused by the fact that transports exist outside of the XMPP server itself - that Jive Software has introduced a new way of using IM network gateways in its OpenFire (formerly WildFire) XMPP based messaging platform. Essentially, transports have been integrated into the platform using a plug-in architecture.

"With OpenFire, you can just register to AOL or any other transport. Once you enter your password, your buddies just appear in your contact list," says Matt Tucker, OpenFire's CTO. " If you subsequently unsubscribe or delete your registration information for AOL, your AOL buddies will disappear automatically. You won't be left with dead links," he says.

The plug-in offers transports to AIM, MSN, ICQ and Yahoo!, and an admin console allows system administrators to control the privileges of individual users or groups of users, dictating which public networks they should be allowed to connect to. The commercially available Enterprise Edition of the platform also enables administrators to archive messages sent and received from public networks for compliance purposes.

The primary benefit of the new architecture is convenience – and the value of convenience shouldn't be underestimated. Enterprise instant messaging is essentially a productivity tool, saving time and increasing collaboration and communication. It makes sense to ensure it's used to its maximum potential, but if it is hard or inconvenient for administrators to enable gateways or for users to add contacts then at least some probably won't bother. "From an administration perspective installing and setting up gateways in now far easier," says Tucker. "You can plug in a gateway without even restarting the server, whereas before you had to download extra libraries, set up extra server processes, then connect to an XMPP server. What used to take 45 minutes now takes 45 seconds."

The new OpenFire transports certainly promise to simplify things, then, but few things can beat a hosted solution if it's simplicity you're after. It was most likely this type of thinking that prompted Google to introduce its Google Apps Premier Edition last February. This includes the XMPP-based GoogleTalk instant messaging and VoIP service, potentially enabling administrators to turn over responsibility for running the enterprise instant messaging system to Google. They can do this while retaining the ability to manage and administer the system (adding and removing users, for example), from a Web-based control panel.

Any transition could be seamless (depending on your existing messaging platform) because Google can link the service to your existing corporate domain name so that none of your corporate instant messaging addresses need to be changed. As an XMPP based system, GoogleTalk can now federate directly with any other XMPP based system, and can also interoperate with IBM SameTime enterprise instant messaging systems. Standard gateways are also available for connection to public networks.

There's a perception that this kind of hosted service is aimed at smaller companies, but it's one which Google is keen to change. "We are targeting this at companies of all sizes from SMBs to large enterprises," says Rajen Sheth, product manager for Google Enterprise. "Basically there is no limit as to how far it will scale. We have tens of millions of users already, and our biggest customer currently has 65,000 users."

Six or seven years ago many companies had concerns about handing parts of their IT infrastructure to application service providers, and probably quite rightly so: most of these ASPs - and many had the word "App" in their name - are long gone. But Google is not a company which is likely to disappear any time soon, and views on application hosting have changed over the last few years as web native applications have become more common. "People do voice concerns but many companies are becoming comfortable. There's been a mindset shift and we are a big company which can offer more data security than most enterprises," he says.

For small companies, the Premier Edition may certainly look attractive at $50 per user per year – and remember this includes email, calendaring and document and spreadsheet sharing capabilities as well as enterprise instant messaging if you want them – but for larger companies this starts to look expensive compared to the cost of running something like OpenFire.

XMPP is still a long way from being the standard for instant messaging, but thanks to innovations from the likes of OpenFire and Google, it's certainly easier - and quite possibly cheaper - to run an XMPP based enterprise IM system that can connect to the public networks using transports than ever before.