User Manual Part 2

Link CX-24 User’s Manual
Version 1.0 Page 43 February 2004
Section 3
Monitoring and Trend Analysis
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3.1 Built-In Web Server Interface
Each Link CX-24 and radio link can be monitored through either the built-in Web server or SNMP agent
interfaces.
A subset of the SNMP-accessible statistics is available through the Web server interface connected to a
web browser over an Ethernet link. These statistics can be read by logging in to display the Monitor page,
as shown in Appendix C. Statistics can be repeatedly sampled using the Web browser reload or refresh
feature.
The easiest indicator to monitor is the RSSI. Keep a record of the RSSI levels measured in Step 55 in
Section 2. The Step 55 value is the RSSI level with Automatic Tx Power Control disabled (transmitting at
maximum power), with Automatic Tx Power Control disabled.
A properly designed radio link with a 20 dB or greater fade margin should indicate receive levels in the
area of -60 dBm at Link CX-24 sites. The accuracy of the indicated RSSI is approximately ±5 dB over a
range of -90 dBm to -65 dBm.
3.2 SNMP Network and Element Management Systems
3.2.1 SNMP Details
All monitored statistics are available through SNMP queries. In addition to MIB-II variables, product-
specific variables are available through the Link CX-24 enterprise MIB, which can be retrieved via FTP
from F:/PUB/link_cx.mib (text file) in the Link CX-24 file system. Most commercial SNMP NMSs and
EMSs have the ability to sample variables over time and display trends and raise alarms based on
defined thresholds. In addition, applicable SNMP traps are supported and can be used to raise alarms on
the NMS and/or EMS.
Any standard SNMP NMS or EMS can be used to monitor and control the Link CX-24 network and
individual Link CX-24 radios.
The Link CX-24 has an enterprise MIB provided in standard ASCII format, which can be accessed for
printing. When a software upgrade is performed, the self-extracting file places all directories and
associated files necessary for the upgrade in a location specified by the operator at the time the self-
extracting file is executed. One of the directories created is /PUB, which contains the printable enterprise
ASCII text MIB file named link_cx.mib.
The enterprise MIB file is also stored in FLASH memory on the Link CX-24 in F:/PUB. A copy of the
link_cx.mib file can be extracted from the Link CX-24 using an ASCII FTP file transfer.
3.2.2 Monitoring Error Messages and Traps
The Link CX-24 supports the generic SNMP traps and Link CX-24 enterprise traps. When an error (or
informational) message is generated by the router, an SNMP trap is issued (when enabled), and the
message is also written to an error log maintained within the router. The router’s error log table holds the
last 256 error messages and can be queried through SNMP reads. Refer to Appendix E for a detailed list
of router-specific messages and traps.
The error log is read ten entries at a time. To do an SNMP read of the first (oldest) ten entries, perform
the following SNMP operations: