Regarding N311 and N310, which of the following descriptions are correct? (Multiple choice)
A . N310 indicates the maximum number of consecutive "synchronous" indications received from the underlying layer
B . N311 indicates the maximum number of consecutive "out of step" indications received from the underlying layer
C . N311 indicates the maximum number of consecutive "synchronous" indications received from the underlying layer
D . N310 indicates the maximum number of consecutive "out of step" indications received from the underlying layer
Answer: CD