Which two can be transported in one AU-4？ （）

单项选择题HowisSNCPandMS-SPRingtrafficreroutedduringaprotectionswitchwhenacompletefibercablecutoccurs？（）

A. SNCP traffic is switched from the first node that recieves the AIS.  MS-SPRing traffic is rerouted from the first in the ring.
B. SNCP traffic is selected at the destination node in the ring.  MS-SPRing is rerouted from the originating node in the ring.
C. SNCP traffic is rerouted from the originating node in the ring. MS-SPRing traffic is rerouted from the originating node in the ring.
D. SNCP traffic is selected at the destination node in the ring. MS-SPRing traffic is rerouted from the last reachable node in the ring.

单项选择题AVC-4-4cconsistsof（）.

A. an STM-16
B. any four VC-4s
C. four contiguous VC-4s
D. four contiguous STM-4s
E. two groupings of four VC-4s

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.