Figure 9-5 Physical Layer Statistics
Current Sample Specifies the number of seconds elapsed within the current sampling period.
SONET/SDH counters are accumulated over a period of 15 minutes (900 seconds). At the end of the 15 minute sampling period, the software stores the results of the current sampling period, and resets the values shown on the screen to zero.
The results of the previous 96 sampling periods can be accessed through the SONET MIB using a MIB Browser.
ATM Physical Layer Statistics |
Physical Layer statistics are broken down into the following layers:
■Path — The Path Layer deals with the mapping of ATM cells to SONET or SDH frames. The ATM Module supports 1 path.
■Line — The Line Layer provides synchronization and multiplexing functions for the Path Layer across the physical medium.
■Section — The Section Layer deals with framing, scrambling, and section error monitoring.
Physical Layer errors are measured in units called Seconds: each Second is a second in time.
In the following statistics a second is considered errored if it contains a Coding Violation.
A coding violation occurs when the parity check in the SONET or SDH frame indicates that the cell payload has been corrupted.
A second is considered severely errored if it contains 16 coding violations for a path or section, or 32 coding violations for a line counter.
A second is unavailable if 10 continuous severely errored seconds are seen at the ATM interface. A second becomes available again, when 10 consecutive seconds are received that are not severely errored.
