Hi Andreas,
hi kelum,
in order to use sip, you need jolly/new branch of lcr and jolly/rtpmux of openbsc. the sip implementation of LCR is quite simple, so no authentication or oder features - just simple point-to-point SIP. if you run confiure of LCR, check if sip is enabled. in order to add a SIP interface, do the following at interface.conf:
[sip]
sip <local ip>[:<local port>] <remote ip>[:<remote port>]
earlyb yes
tones no
you need to define local IP that will be used to connect to remote SIP endpoint. don't use localhost, if the endpoint is on a different machine, because this IP is also used for RTP. if you use same machine, you need to have different ports. you may change local port, by adding a local port or you may change port of SIP endpoint and then add remote port.
i have tested it with freeswitch, but asterisk should work also.
you may then also try at interface.conf below "[sip]" definition:
rtp-brige
then the codec (full rate or enhanced full rate) is negotiated between mobile and the remote SIP endpoint. the SIP endpoint must support at least one of it.
regards,
andreas