[OpenSBC] hold call in Full mode

[OpenSBC F. <ope...@op...>]

Hi all, i'm new to using OpenSBC. i have questions about holding a call


in my case, i use OpenSBC as a SIP proxy (run in Full Mode). And there are two SIP softphone registered to it.


Suppose the two phones are phoneA ([ph...@te...]) and phoneB([ph...@te...])


the case is that phoneA dial to phoneB and the dialog is established already and they can talk to each other. The problem is that when the user press "HOLD" button in phoneA, phoneB doesn't know the call is held by phoneA. 


i read the log from both soft phones. I find that after phoneA sending re-Invite to proxy and the proxy reply OK to phoneA but the proxy doesn't send the re-Invite request to phoneB, so phoneB doesn't know phoneA requesting call hold.


i want to ask what is the reason for the proxy not sending request to phoneB and how can i fix it such that holding call can be successful.


Thank you very much in advance