多项选择题
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.
单项选择题 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？（）
多项选择题 WhichtwocanbetransportedinoneAU-4？（）