The TCP/IP Guide  9  TCP/IP Application Layer Protocols, Services and Applications (OSI Layers 5, 6 and 7)       9  TCP/IP Network Configuration and Management Protocols (BOOTP, DHCP, SNMP and RMON)            9  TCP/IP Network Management Framework and Protocols (SNMP and RMON)                 9  TCP/IP Simple Network Management Protocol (SNMP) Protocol                      9  SNMP Protocol Operations

SNMP Protocol Object Modification Using SetRequest Messages 1 2 SNMP Protocol Security Issues and Methods

Use of the SNMPv2 InformRequest Message

SNMPv2 also incorporates a second notification message type: InformRequest-PDU. This type of message is not the same as a trap, but it is related to traps for two reasons. First, both message types are used to communicate information without the recipient initiating the process, and second, the two messages are sometimes used in conjunction.

The purpose of the InformRequest-PDU is actually to facilitate the communication of information between network management stations. The SNMP Manager on one NMS can choose to “inform” another of some piece of information by sending an InformRequest-PDU to that other SNMP Manager. The receiving manager then replies back with a Response-PDU to the one that sent the InformRequest-PDU, confirming receipt of the inform message.

A common way that this message is used is to “spread the news” when a trap occurs. Suppose a device experiences a power failure, which results in a Trapv2-PDU being sent to NMS #1. The network administrator may want to set up NMS #1 so that receipt of particular traps causes the information in the trap to be “forwarded” to another. The InformRequest-PDU would be used to carry that information from NMS #1 to say, NMS #2.

SNMP Protocol Object Modification Using SetRequest Messages 1 2 SNMP Protocol Security Issues and Methods