Anrtisu Cell Master MT8212B, User Manual, Page: 205 / 294

G.821 Measurement Definitions
Available Seconds (AS)
¾ The count of available seconds since the beginning of the test.
Available seconds equals the total test time minus any unavailable seconds.
Degraded Minutes (DGRM)
¾ The count of Degraded Minutes since the start of the test. A
Degraded Minute occurs when there is a 10-6 bit error rate during 60 available, non-se-
verely bit errored seconds.
Error Free Seconds (EFS)
¾ The count of error free seconds since the beginning of the test.
Error free seconds equals the total test time minus the number of errored seconds.
Errored Second (ES)
¾ The number of seconds with at least one error.
Severely Errored Seconds (SES)
¾ This is the count of Severely Errored Seconds since the
beginning of the test. A second with a bit error rate of 10-3 or higher is a severely errored
second. Severely errored seconds are not counted during unavailable time. Loss of signal
(LOS), loss of frame (LOF) and loss of pattern synchronization (LOP) are treated as se-
verely errored seconds
Unavailable Seconds (UAS)
¾ This is the count of UnAvailable Seconds that have occurred
since the beginning of the test. Unavailable time begins at the onset of 10 consecutive se-
verely errored seconds, and ends after 10 consecutive non-severely errored seconds. The
onset of unavailable seconds cause the SES count to be adjusted downward by 10. When
unavailable time ends, the UAS count is adjusted downward by 10.
Network Equipment
One possible network topology is shown in Figure 10-2.
The circuit between the MSC and BTS passes through the central office, or through multi-
ple central offices. Within each office it may in turn pass through multiple pieces of trans-
mission equipment. An interface unit is located at the MSC and the BTS. The interface unit
may be a very simple device having only a remote loop back capability, or it may provide
very sophisticated performance monitoring capabilities. Its capabilities may or may not be
accessible to the wireless service provider technician.
10-2
Chapter 10 E1 Measurements
MSC
BTS
E1 BACKHAUL
Figure 10-2. One Possible E1 Network Topology