7.4. Using SNMP for Measurements and Monitoring

The SBC provides SIP and RTP traffic related counters. These measurements are exposed to external monitoring tools using SNMP API. The administrator can also manually use standard snmp tools (e.g. “snmptable” or “snmpwalk” commands).

The SNMP daemon uses the external management interface (XMI) and is configured in “System ‣ SNMP“ screen. The ABC SBC collects general, per Realm/Call Agent and user defined measurements. Complete SBC counters specification in MIB format is available in the “ /usr/share/snmp/mibs/FRAFOS-STATS-MIB.txt“ file.

7.4.1. General Statistics

General statistics present the number of the calls currently processed by the system.

  • fSBCCalls - number of active calls
  • fSBCCallStarts - number of call attempts
  • fSBCBits - RTP Bits relayed
  • fSBCRegs - number of SIP registrations

The following example shows the current number of calls. Note that on your system you must use its administrative IP address instead of the address shown in the example and that the -c parameter must be set to the current SNMP community value if changed under “Config ‣ Global Config”:

% snmpwalk  -v 2c -c sbc_com_321 FRAFOS-STATS-MIB::fSBCCalls

7.4.2. Statistics per Realm / Call Agent

These measurements are counted for each Realm and Call Agent separately.

  • UUID - unique identifier
  • Name - Realm resp. Call Agent name
  • RealmName - Realm name which a Call Agent belongs to (shown for call agent only)
  • CallsStartsTo - number of call attempts to the Realm/Call Agent
  • CallStartsFrom - number of call attempts from the Realm/Call Agent
  • CallsTo - number of call attempts to the Realm/Call Agent (including calls in progress)
  • CallsFrom - number of call attempts to the Realm/Call Agent (including calls in progress)
  • BitsTo - RTP Bits relayed to the Realm/Call Agent
  • BitsFrom - RTP Bits relayed from the Realm/Call Agent

The following example provides a snapshot of statistics collected by the ABC SBC using the snmptable command:

# snmptable -v 2c -Cb -CB -c sbc_com_321  -Oqq FRAFOS-STATS-MIB::fSBCRealmStatsTable
SNMP table: FRAFOS-STATS-MIB::fSBCRealmStatsTable
                                UUID      Name CallStartsTo CallStartsFrom CallsTo CallsFrom BitsTo BitsFrom
1356fb76-290c-cc49-4b46-00007784bfc6 sip-realm            2              0       2         0  42656    51690
5fa54bf5-01d5-56e9-23b4-000019b29424 rtc-realm            0              2       0         1  51690    42656

7.4.3. User Defined Counters

User defined counters can be created and increased using an “Increment SNMP counter“ action configured in inbound or outbound rules. This action increments a user-defined SNMP counter by a given value. As parameters the counter name and the counter increment are given, see Fig. User defined counters.


Figure 1: User defined counters

The value of the custom counters can be queried using the snmptable command:

% snmptable -v 2c -Cb -CB -c sbc_com_321 public  -Oqq FRAFOS-STATS-MIB::fSBCCustStatsTable
FRAFOS-STATS-MIB::fSBCCustStatsTable.1.2.1 "gui.alice_calls"
FRAFOS-STATS-MIB::fSBCCustStatsTable.1.3.1 12

7.4.4. SNMP traps

The SNMP daemon can generate SNMP traps (alerts). This functionality is disabled by default and can be enabled in “Config ‣ SNMP“ screen by entering the trap receiver (manager) address. The generated traps can use SNMP protocol v1 or v2c (or both, but do not send both to the same receiver). The time interval between checks and sending the SNMP traps is 10 minutes. The SNMP traps are sent when any of the following conditions is met, and only if the check state changes since last check:

  • system interface link goes down or up
  • disk free space drops below 10%
  • system load gets over 15 (1min average) or 10 (5min average) or 5 (15min average)