Table of Contents
Advertisement
Chapter 7
Advanced Configuration
94
7.2 SNMP
Function
The Simple Network Management Protocol (SNMP) is used to refer to a collection
of specifications for network management that include the protocol itself, the
definition of data structures and associated concepts.
SNMP
A management station performs the monitoring function by retrieving the value of
MIB objects. The management station and agents are linked by a network
management protocol called SNMP. The SNMP includes three key capabilities
Get
Set
Trap
A single management station can handle many agents as long as SNMP remains
relatively "simple", so the number can be high (hundreds or so).
Example
The following picture is the typical configuration of protocols for SNMP.
As for a stand-alone management station, a manager process controls access to a
central MIB at the management station and provides an interface to the network
manager. The manager process achieves network management by using SNMP,
which will be implemented on top of the UDP, IP and the relevant network-
dependent protocols (for example, Ethernet).
For an agent device that supports other applications, such as FTP, both TCP and
UDP are required. An agent may issue a trap message in response to an event that
effects the MIB and the underlying managed resources.
There are no ongoing connections maintained between a management
station and its agents. Instead, each exchange is a separate transaction
between a management station and an agent.
Traps
Each agent is responsible for notifying the management station of any unusual
event. For example:
If the agent crashes and is rebooted
A link fails
An overload condition as defined by the packet load crosses some threshold
...
These events are communicated in SNMP messages known as traps.
E-DOC-CTC-20041126-0014 v3.0
Advertisement
Table of Contents
