OpenSIPS RLS (Resource List Server) with integrated XCAP
Resource List Servers (RLS) is an extension for S IP protocol which provides mechanism for subscribing to a homogeneous list of resources (RFC 4662). Usually end-to-end presence requires SUBSCRIBE packet for each buddy which user wants to watch. As a result, for each single presence or dialog etc. event, server would send separate NOTIFY packet. While RLS would require only one SUBSCRIBE packet which refers to the list of buddies that user wants to watch. RLS server will respond with one NOTIFY packet with information for all contacts packed in NOTIFY body as XML document. Obviously this can dramatically decrease network traffic in installation with thousands of users. RLS usually configured in with XCAP servers, which also allows to manages buddy list and access. OpenSIPS can be integrated with OpenXCAP server which is a fully featured XCAP server written in python. There are also some additional information about RILS...