单项选择题
A. the K1 SONET byte； the K2 SONET byte
B. the K2 SONET byte；the K1 SONET byte
C. transmitter switching；receiver detection
D. Line Overhead bytes；Path Overhead bytes
E. Path Overhead bytes；Line Overhead bytes
单项选择题 On an ONS 15454 node you can tunnel an （）.
单项选择题 In order to avoid misconnections due to a failed node in a Bidirectional Line Switched Ring (BLSR), 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 How is UPSR and BLSR traffic rerouted during a protection switch when a complete fiber cable cut occurs?（）