SNMP Agent Key Concepts

Monitoring your high-performance messaging with 29West's SNMP monitoring solution involves running the SNMP Agent on every machine running LBM/UME applications. The Agent uses the LBM Monitoring API to receive statistics from the various 29West messaging applications running on the machine. As the Agent receives statistics, it updates the appropriate MIB table entries to reflect the latest values. Your SNMP console then pulls statistics from the 29West MIB for display or analysis.

If you are already using the LBM Monitoring API, you can simply add a different transport module (lbmsnmp) to implement SNMP Agent.

What Can I Learn about My Multicast Receivers?

LBM Monitoring collects 21 different statistics for receivers in multicast transport sessions. The following discusses just some of the information that can be supplied to your SNMP monitoring system for both individual transport sessions and aggregated statistics.

  • Number of LBM messages can give you a receiving rate that can be compared over time or across different receiving machines.
  • Number of application messages received that were not sent on a topic of interest to the receiver. If this number is high, you may consider reconfiguring sources so that more filtering may be done at the network layer.
  • Number of lost messages can give you a loss rate that can be compared over time or across different receiving machines.
  • Mean loss recovery time should be close to your minimum loss recovery time. High mean recovery times indicate a lossy network.
  • Number of NCFs ignored. A source sends an NCF ignored if it receives a NAK for a datagram that it has recently retransmitted. A high value for NCFs ignored indicates the receiver is having trouble receiving retransmissions.

What Can I Learn about My Multicast Sources?

LBM Monitoring collects 12 different statistics for sources in multicast transport sessions. The following discusses just some of the information that can be supplied to your SNMP monitoring system for both individual transport sessions and aggregated statistics.

  • Divide retransmissions sent by number of messages sent to find the ratio of retransmissions to new messages.
  • Divide NAKs shed by NAKs received to find the likelihood that excessive NAKs were ignored, which indicates receivers are having trouble receiving retransmissions.
  • Divide NAKs received by number of messages sent to find the likelihood that sending a message resulted in a NAK being received. Expect no more than a few percent on a network with reasonable loss levels.
  • Number of retransmissions queued by the retransmission rate controller. A high number of queued retransmissions indicates a high amount of loss recovery occurring. Consider increasing the retransmission rate controller limit or reducing loss to avoid retransmissions.

Other SNMP Agent Details

  • Messaging SNMP Agent acts as an SNMP master agent, meaning it directly receives and processes SNMP requests, and responds with SNMP responses.
  • The Agent uses only the request/response portion of the SNMP protocol. It does not implement any SNMP traps.
  • The 29West Messaging SNMP Agent requires Version 2c of the SNMP protocol.