1
SMART
RADIO
Technical Bulletin 3/14
THE SNMP PROTOCOL
The Simple Network Management Protocol,
SNMP is a widely used management protocol
that operates on top of IP and UDP protocols.
In the basic mode of operation the SNMP is a
Request / Response protocol. Please refer to
SATEL Technical Bulletin 1/14 for more
information about Get /Set operation. SNMP
also supports unsolicited notifications, or traps,
that are sent by the device (SNMP Agent) to the
server (SNMP Manager). These notifications
could be about configuration or state changes,
alarms about critical event or monitored value
exceeding the threshold.
THE SNMP NOTIFICATION
The unsolicited messages sent by the agent to
the server are called notifications in SNMP
version 2 and 3. The original SNMP version 1
has a bit different format for these messages, so
they are called traps. In SNMPv2/3 the
notifications are identified similarly to Get / Set
procedure: with OID (Object Identifier). For
example, notification about temperature would
be identified by the OID: 1.3.6.1.4.1.30306.1.1.1.5.4.
The SNMPv2/3 notifications also include a
notification text, for example: “RSSI has
dropped to -128, it is below the set
minimum -110!”
MIB
Mappings between OID numbers and
parameters are stored in a tree formatted
hierarchical database called Management
Information Base, MIB. To enable SNMP
notifications of a certain parameter, both the
Manager and the Agent must have respective
OID available in their MIB. The MIB database
contents for SATELLAR related parameters are
available for download at SATEL web pages.
After download, they can be installed or
imported to the Manager MIB.
SIMPLE NETWORK MANAGEMENT PROTOCOL
SATELLAR MONITORING WITH SNMP NOTIFICATIONS
1
RSSI too low!
The OID
1.3.6.1.4.1.30306.1.1.1.5.3
matches with the RSSI level.
RSSI too low!
2
2
SNMP MANAGER SOFTWARE
EXAMPLE
snmpb
Easy and simple to use
Allows easy testing of Notifications
Listing of received traps
Easy browsing of MIBs
SNMP Get / Set queries available
Supports SNMPv3 with enhanced security
No visual network monitoring
AVAILABLE MEASUREMENTS
Notification sending in SATELLAR is available for
the following measured values:
Voltage
RSSI (Received Signal Strength Indication)
Temperature
SNR (Signal to Noise Ratio)
Also, a notification of user committing the
configuration changes (Commit) is available.
Too
high!
Too
low!
Too
low!
Too
low!
Too low!
Voltage
Temperature
SNR
RSSI
Too high!
MEASUREMENT RESULT READING
Measurement results are read and checked
with configurable intervals. Checking is done
against user-configured thresholds. If any
reading is exceeding (or being below) the
threshold a SNMP notification is sent. It is also
sent when the measurement reading is
returned back to the allowed range.
Note! The temperature reading will result
non-zero value only after the first radio
transmission. Furthermore, the temperature
operations with SNMP are always in Celsius.
Time
Notification interval
read read read read
MIB
Browser
GET / SET
Query
Detailed listing of
received notifications.
Agent
(SATELLAR)
configuration