In　the　recent　years,　Voice　over　Internet　Protocol　(VoIP)　is　the　most　popular　technology　and　becomes　a　kind　of　killer　application,　and　802.11-based　wireless　Local　Area　network　(WLAN)　has　been　set　up　in　many　public　places.　People　who　use　VoIP　over　WLAN　can　be　more　convenient.　In　the　common　WLANs,　IEEE　802.11e　WLAN　can　support　VoIP　with　better　Quality　of　Service　(QoS),　However,　802.11　lacks　a　flexible　mechanism　to　adapt　to　the　varying　wireless　channel　condition.　The　idea　of　this　research　project　is　to　promote　the　use　of　VoIP　that　uses　IPv6　and　to　exploit　the　IP　protocols　over　WLAN　(Wireless　Local　Area　Network).　Specifically,　we　show　a　cross-layer　framework　for　design　of　wireless　networks　to　support　delay-critical　applications,　such　as　conversational　voice　or　realtime　video.　The　framework　incorporates　adaptation　across　all　layers　of　the　protocol　stack　to　leverage　the　flexibility　offered　by　joint　optimization　of　design　parameters.　There　are　several　network　features　that　can　be　exploited　to　minimize　delay,　reduce　delay,　and　maximize　performance.　With　the　assistant　of　the　active　scheme,　it　can　be　avoid　the　longest　phase　that　IEEE　802.11　will　enter.　And　implement　a　policy-based　802.11e　WLAN　to　protect　the　right　of　user　who　has　applied　real-time　services,　©　2010　IEEE.