User's Manual

Exalt Communications, Inc.
EX-5r Installation & Management
5000007 44
2006-05-17
5.13 Performance Page
The Performance Page provides statistical information about the performance of the system in
relation to the integrity of the user data and the RF link. The list below provides a brief summary
of this information.
• Current BER indicates the current Bit Error Rate of the link. If the link is operating
perfectly, this should indicate zero. Generally, the link should remain at a BER less
than 1x10
-6
(1 bit out of every million bits errored). This is the threshold performance
specification and the standard to which the link was engineered. However, radio links
can and will be affected by weather, interference and other external sources and will
occasionally have a higher error rate. A link will remain operational unless the BER
exceeds 1x10
-3
(1 bit out of every hundred bits errored). Consult the link design
engineer for an understanding of the predicted error rate of the radio link as it has been
designed. Many applications will be largely unaffected by bit errors, but TDM circuits
(e.g. T1 or E1) are more sensitive. Also, if the link operator is providing a service
guarantee, this value may need to be monitored or examined in cases of service issues.
The behavior of BER in relation to other alarms or measurements and external events
can be very helpful in troubleshooting activities.
• Current RSL is the measurement of the received signal level at the radio antenna port.
This is the measured level of the RF signal coming from the opposite end of the radio
link. The link was engineered to a specific RSL by the link design engineer, and this
RSL should be obtained during installation and stay relatively stable during the
operation of the link. RSL can and will vary as a result of weather changes and other
external sources, such as path obstructions. Once again, this variation was part of the
original design to achieve a certain level of performance over time. When the RSL
falls to a level within roughly 3dB of the threshold specification, bit errors will occur.
When the RSL falls below the threshold specification, the link will disconnect and
will not reconnect until the RSL is above the threshold specification. The behavior of
RSL in relation to other alarms or measurements and external events can be very
helpful in troubleshooting activities.
• Errored Seconds (ES) indicates the total number of seconds that have occurred where
there has been at least one bit error, since the last time that the radio statistics counter
has been reset. Generally, ES are not a significant concern, so long as they are not
continuous or above the anticipated performance based on the original link
engineering goals. If ES are continuous or at a high rate, this is normally an indication
of poor link performance due to poor RSL or interference, or severe impact by
weather or other environmental factors. However, similar to the performance factors
listed above, ES can and will occur in any radio link. Once again, the link engineer
should be consulted to determine the original design goals, and compare actual
performance to these expectations to determine if any improvements are necessary or
if other problems may be causing excessive ES.
SES (as described below) do not register as ES. In other words, the ES counter will
count ONLY seconds that are errored and are not SES.