单项选择题

Which timing mode is most appropriate for an ONS 15454 that has lost its BITS-1 and optical references？（）

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

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热门试题

单项选择题

Whichisalegitimatebandwidthmatchedpair？（）

A. DS-1； E1
B. DS-1； STM-1
C. OC-3； STM-1
D. STS-1； STM-1
E. OC-192； STM-192

多项选择题

WhataretwomajordifferencesbetweenMS-SPRingandSNCP？（）

A. In an MS-SPRing， all paths are protected.
B. MS-SPRing is always a high-order protection.
C. A low order circuit cannot be protected by an MS-SPRing.
D. There is no theoretical limit in the number of nodes in an SNCP ring.