Ekiga is basically Gnomemeeting with SIP capabilities added. We used Ekiga to discover codec-related problems and to conveniently test Asterisk's setup.
At a certain point it was not clear any more which protocols Ekiga was using: after having set up a H323 account, removing the gatekeeper parameters makes it impossible to make any calls.
Moreover, Once a SIP account is created and used, Ekiga starts to listen to all the SIP ports even if the SIP account is disabled.
These and other fuzzy behaviors led us back to Gnomemeeting which can only support H323.
The configuration of Ekiga is the same as that of Gnomemeeting