When using simultaneous voice and multicast on a single WLAN and RF band, what is the recommended DTIM value of the WLAN for VoWLAN devices?（）

单项选择题WhatistheWMMuserpriorityofthepacketsgoingdownstreamtotheclientwhentheclientdoesnot supportTSPECbuttheCiscoWLChasACMenabledandWLANpriorityissettoPlatinum?（）

A.background
B.best effort
C.voice
D.video

多项选择题Whichthreeareinterframespacesdefinedin802.11?（）

A.SIFS
B.PIFS
C.DIFS
D.LIFS
E.NAV
F.CWmin

单项选择题WhatisthepayloadsizeofawirelessIPphoneinacallusingG.711codec?（）

A.20 bytes
B.60 bytes
C.120 bytes
D.160 bytes

单项选择题WhatcallperformancestatisticsarereportedontheCiscoWirelessIPPhone7921userinterface?（）

A.minimum jitter
B.maximum jitter
C.upstream standard packet deviation
D.average MOS value
E.average conceal rate

单项选择题WhichstatementdescribesthecallbehavioroftheCiscoUnifiedWirelessIPPhone7921Gwhenit roamsfrom802.11bto802.11a?（）

A.The phone does a directed call hangup on 802.11b，then does an auto-redial on 802.11a，creating a  new call.
B.The phone does a directed call hangup on 802.11b， then the user does a redial on 802.11a，creating a  new call.
C.The phone does a disassociation on 802.11b and an association on 802.11a，and call remains up if the  subnet has not changed.
D.The phone does not roam from 802.11b to 802.11a when on an active call.
E.The phone must switch network profiles to roam from 802.11b to 802.11a.