If node 2 is accepting line timing from node 1, node 2 will send （）to node 1 as its SSM message.

单项选择题SONET Code Violations (CVs) totals in the PM tables are actually an accumulation of the number of （）.

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

单项选择题Scrambling of SONET signals is done to （）.

A. prevent the leakage of external fiber emissions
B. provide the optical network with the highest level of security possible
C. assure an even distribution of 1's and 0's for extended transmitter life
D. assure an adequate number of transitions for clock recovery at the receiver
E. prevent the receiver from assuming AIS inadvertently when all 0's are received

单项选择题A Channel ID mismatch occurs when （）.

A. fibers are terminated incorrectly on a node
B. the channel number in the received K1 byte is not identical to the channel number transmitted in the K2 byte
C. the channel number in the received C1 byte is not identical to the channel number transmitted in the C2 byte
D. the channel number in the received C2 byte is not identical to the channel number transmitted in the C1 byte
E. the channel number in the received K2 byte is not identical to the channel number transmitted in the K1 byte

单项选择题The ML-series Ethernet card on the ONS 15454 provides up to （）active Q-in-Q instances per card.

A.255
B.512
C.1024
D.4096

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