单项选择题
YouarethenetworkadministratorofanenterprisecompanythatjustdeployedaglobalIPtelephonyenvironment.Inordertoguaranteegoodvoicequality，youaskedyourprovidertoimplementQoSontheCEroutersofyourMPLSnetwork.OnyourLAN，youhavealsodeployedQoS.Users，however，keepcomplainingaboutbadvoicequality，andtheproviderdoesnotseematchesontheDSCPvaluesthatyouhaveaskedhimtomatchupon.Whatismostlikelytheproblem？（）
A.ThephonesarenotsendingtrafficwiththecorrectDSCPvalue.
B.TheCiscoCallManagerisnotmarkingthetrafficcorrectly.
C.ThisismostlikelyabugontheCErouters.
D.YourLANQoSisincorrectlyconfigured.
A.Inordertoguaranteegoodvoicequality，youaskedyourprovidertoimplementQoSontheCEroutersofyourMPLSnetwork.OnyourLAN，youhavealsodeployedQoS.Users，however，keepcomplainingaboutbadvoicequality，andtheproviderdoesnotseematchesontheDSCPvaluesthatyouhaveaskedhimtomatchupon.Whatismostlikelytheproblem？（）
A.ThephonesarenotsendingtrafficwiththecorrectDSCPvalue.
B.TheCiscoCallManagerisnotmarkingthetrafficcorrectly.
C.ThisismostlikelyabugontheCErouters.
D.YourLANQoSisincorrectlyconfigured.
