Dispatcher; Message Processing Subsystem - Cisco WS-C4003 - Catalyst 4000 Chassis Switch Software Configuration Manual

Understanding SNMPv3
Figure 23-1 SNMP Entity for Traditional SNMP Agents
UDP

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 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.
Software Configuration Guide—Catalyst 4000 Family, Catalyst 2948G, Catalyst 2980G, Releases 6.3 and 6.4
23-8
IPX
Other
Dispatcher
Transport Mapping
Message Dispatcher
PDU Dispatcher
Proxy
foward
applications
MIB Instrumentation
SNMP Entity
Message Processing
Subsystem
v1MP
v2c MP
v3MP
otherMP
Command Notification
responder
applications applications
Chapter 23
SNMP Engine
Security Access Control
Subsystem Subsystem
User-based View-based
security access control
model
Other
access control
security
model
originator
SNMP Applications
Configuring SNMP
model
Other
model
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