Kelpie is a SIP to XMPP gateway
It attempts to make sip endpoints appear as xmpp endpoints and vice-versa
The gateway only focuses on protocol translation, a SIP proxy (such as Kamailio) and a federated xmpp server are required for routing.
XMPP->SIP
This is the easiest case, the xmpp client adds user@{kelpie.hostname} to his contact list, this gets translated as user@{outbound.siproxy} and the proxy routes teh messages
SIP->XMPP
This direction is more complicated.
The sip proxy should identify that user is actually an xmpp endpoint and forwards to the kelpie gateway. Kelpie has a mapping of "user" to xmpp ids in it's properties file, if it is found it forwards the message to the specified xmpp server.
example:
com.voxbone.kelpie.mapping.user=user@jabber.org
would mapp sent to sip:user@{kelpie.hostname} to user@jabber.org
if you don't want to use the mapping file, the format
sip:user+xmpp-server@{kelpie.hostname} can also be used instead