Cisco WS-C2980G-A Software Guide - Page 380

Understanding SNMPv3 Chapter 24 Configuring SNMP Figure 24-1 SNMP Entity for Traditional SNMP Agents UDP IPX Other SNMP Entity Dispatcher Transport Mapping Message Dispatcher PDU Dispatcher Message Processing Subsystem v1MP v2c MP v3MP otherMP Security Subsystem User-based security model Other security model SNMP Engine Access Control Subsystem View-based access control model Other access control model Proxy foward applications Command responder applications Notification originator applications MIB Instrumentation SNMP Applications Dispatcher The Dispatcher is a simple traffic manager that sends and receives messages. After receiving a message, the Dispatcher tries to determine the version number of the message and then passes the message to the appropriate Message Processing Model. The Dispatcher is also responsible for dispatching protocol data units (PDUs) to applications and for selecting the appropriate transports for sending messages. Message Processing Subsystem The Message Processing Subsystem accepts outgoing PDUs from the Dispatcher and prepares them for transmission by wrapping them in a message header and returning them to the Dispatcher. The Message Processing Subsystem also accepts incoming messages from the Dispatcher, processes each message header, and returns the enclosed PDU to the Dispatcher. An implementation of the Message Processing Subsystem may support a single message format corresponding to a single version of SNMP (SNMPv1, SNMPv2c, SNMPv3), or it may contain a number of modules, each supporting a different version of SNMP. 58568 24-12 Catalyst 4500 Series, Catalyst 2948G, Catalyst 2980G Switches Software Configuration Guide-Release 8.1 78-15486-01