Managers And Agents - Cisco ACE-4710-K9 Administration Manual

Chapter 8 Configuring SNMP

Managers and Agents

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SNMP uses software entities called managers and agents to manage network
devices:
The manager monitors and controls all other SNMP-managed devices
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(network nodes) in the network. At least one SNMP manager must be in a
managed network. The manager is installed on a workstation somewhere in
the network.
An agent resides in a managed device (a network node). An agent is a
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specialized software module that receives instructions from the SNMP
manager and also sends management information back to the SNMP manager
as events occur. For example, an agent might report such data as the number
of bytes and packets in and out of the device or the number of broadcast
messages sent and received.
There are many different SNMP management applications, but they all perform
the same basic task. These applications allow SNMP managers to communicate
with agents to monitor, configure, and receive alerts from the network
devices.The ACE supports traps and SNMP get requests but does not support
SNMP set requests to configure values on the device. You can use any
SNMP-compatible NMS to monitor the ACE.
In SNMP, each variable is referred to as a managed object. A managed object is
anything that an agent can access and report back to the NMS. All managed
objects are contained in the MIB, which is a database of the managed objects
called MIB objects. Each MIB object controls one specific function, such as
counting how many bytes are transmitted through an agent's port. The MIB object
consists of MIB variables, which define the MIB object name, description, and
default value.The ACE maintains a database of values for each definition.
Browsing a MIB entails issuing an SNMP get request from the NMS. You can use
any SNMPv3, MIB-II compliant browser to receive SNMP traps and browse
MIBs.
Cisco 4700 Series Application Control Engine Appliance Administration Guide
SNMP Overview
8-3