Web In Depth

One of the most important features of modern instant messaging is the interoperability of different clients. Earlier all major players supported their own proprietary protocols and many users had to use several clients to keep in touch with everyone. But after year 2000 we saw the arrival of many newcomers with interoperability in mind. If we consider this scenario there is only two ways to provide this, either the client had to support all the protocols or the server had to support communication between different protocols. Jabber and example of the latter was one of the first on the seen.

What is Jabber?

Jabber is a set of protocols and the technologies build using those protocols for communicating between two points on a network. Jabber has three main features. First it is an open standard. Second it is 100% XML and finally it has a special feature called a gateway.

Let’s look a little bit more closely at Jabber. Essentially Jabber is very akin to email, because it uses same type of client server model. You have a client, log into a server and send your message. The server relays that message using other servers that run Jabber. The server on the receiver’s side sends it to receiver’s client.

The major difference is that servers keep track of when users are online (called presence) which is essential for real time messaging. Now what set jabber apart is the open standard.

Why?

Because anyone can implement a jabber server, buy running jabber server software. Anyone having a domain name, internet connection and computer, which is almost everyone these days. So with so many servers running Jabber it creates a distributed service which differs from the centralized service given by legacy IM clients like MSN,Yahoo.

So what?

A distributed system can handle scalability much better, the best example is the extremely reliable email service.

The most important feature regards to interoperability is a gateway. It is software that can run on any Jabber server and provides proxy like service. Which means it shows a jabber compatible interface to jabber users but a proprietary interface to other services.(Eg: if connecting to Yahoo messenger it will show a Yahoo messenger compatible interface to the network using Yahoo messenger)This means we can easily communicate with friends using other messaging services. Therefore the task of handling multi-protocols fall on server, thus making the client very simple. The simplicity of developing a Jabber client had led to many implementations.

For a full list check here

The other type of interoperability is provided by clients that run multiple protocols. They just use each protocol depending on what service the user is using. This makes the client much more complex and needs professionals to develop it. There are quite a few such clients out there including Pidgin, Trillian, Adium and Miranda.

There has been some other advances in interoperability, which are agreements between major service providers to allow there systems to interact. A good example is the agreements between Yahoo and Microsoft, Google and AOL. These two agreements led to users having one of these accounts to message the other party without having to have another account or client.

Personally I feel much more can be done and much more should be done.