Hello! I have to simulate a two phases MAC protocol in which nodes apply in every phase a different algorithm and exchange different packets , I have to execute an algorithm in background and exchange it's result in the first phase than use those results to elect the node that have the right to transmit it's data packet in the second phase . I will appreciate any help or idea for how to simulate that, have I to use OTCL threads or can I do it in only one MAC C++ file ? I have no idea about how to start !! Thank you very much in advance. _________________________________________________________________ Windows Liveā¢: Keep your life in sync. Check it out! http://windowslive.com/explore?ocid=TXT_TAGLM_WL_t1_allup_explore_012009