Comment by zmb_
11 years ago
>-simple and extendable
It's the first time I hear anyone describe SIP as "simple". If you printed out all the SIP specs, you'd probably have a pile close to a meter high. Among the protocol crowd (including IETFers) SIP is often regarded as an example of protocol design having gone off the rails in a spectacular fashion. It has been repeatedly beat in the market by proprietary protocols that do things better (e.g., see the mess SIP NAT traversal ended up as compared to Skype).
Yes, the SIP protocol is not so simple. However a lot of well working implementations already exists (source code, libraries, ready to use software). The core messaging in SIP (RFC 3428) is extremely simple to add as it is just a single method (MESSAGE).
Adding presence and other funny things with the SIMPLE protocol family is another subject. (However the basic presence is also very simple ...the complications comes when you wish to add file transfer and other fancy things).
But these can be used as an extra so at least the for chat you are fully interoperable with all other vendors.