In order to avoid misconnections due to a failed node in an MS-SPRing， Alarm Indication Signals （AISs） are sent on every channel normally terminating in that node. 
What is the name of this process？（）

单项选择题WhichtimingmodeisappropriateforanSDHNEthatisadjacenttoanSDHNEBits-1timing？（）

A. DUS
B. line timing
C. loop timing
D. internal timing
E. through timing

多项选择题WhichtwocanbetransportedinoneAU-4？（）

A. 3 E3
B. 4 E4
C. 64 E1
D. 21 E1 and 2 E3
E. 42 E1 and 2 E3

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