A VC-4-4c consists of （）.

单项选择题OnanONS15454nodeyoucantunnela（n）（）.

A. SDH circuit over a SONET network delivering it as an SDH signal
B. SDH circuit over a SONET network delivering it as a SONET signal
C. SONET circuit over an SDH network delivering it as an SDH signal
D. SONET circuit over an SDH network delivering it as a SONET signal

单项选择题Ifnode2isacceptinglinetimingfromnode1，node2willsend（）tonode1asitsSSMmessge.

A. AMI
B. DUS
C. ESF
D. PRS
E. SMC
F. B8ZS

单项选择题Whatprotectionmethodisusedin4FMS-SPRingnetworks？（）

A. Each fiber has half of its capacity reserved for protection.
B. Two fibers carry their full capacities while the other two fibers are reserved for protection.
C. The signal is sent simultaneously in both directions around the ring. The receiver determines which fiber to listen to based on signal quality.
D. The signal is sent simultaneously in both directions around the ring. The transmitter determines which fiber has the working bit set for the receiver to acknowledge.

单项选择题InSDH，whatisthenameoftheembeddedDataCommunicationChannel（DCC）inbytesD1-D3？（）

A. the DCC-E
B. the DCC-M
C. the DCC-R
D. the Line DCC
E. the Section DCC

单项选择题SDHCodeViolations（CVs）totalsinthePMtablesareactuallyanaccumulationofthenumberof（）.

A. J0 errors detected in a in a specified interval
B. errors detected in a given Errored Seconds （ES）
C. errors detected in a given Severely Errored Seconds （SES）
D. errors the encryption algorithm detects in a specified interval
E. Bit Interleaved Parity （BIP） errors detected in a specified interval