About Snmp; Figure 54 Access Control; Figure 55 Snmp Management Model - ZyXEL Communications VES-1616F-44 User Manual

VES-1616F/1624F-44 User's Guide

Figure 54 Access Control

17.3 About SNMP

Simple Network Management Protocol (SNMP) is an application layer protocol used to
manage and monitor TCP/IP-based devices. SNMP is used to exchange management
information between the network management system (NMS) and a network element (NE). A
manager station can manage and monitor the switch through the network via SNMP version
one (SNMPv1) and/or SNMP version 2c. The next figure illustrates an SNMP management
operation. SNMP is only available if TCP/IP is configured.

Figure 55 SNMP Management Model

An SNMP managed network consists of two main components: agents and a manager.
An agent is a management software module that resides in a managed switch (this device). An
agent translates the local management information from the managed switch into a form
compatible with SNMP. The manager is the console through which network administrators
perform network management functions. It executes applications that control and monitor
managed devices.
The managed devices contain object variables/managed objects that define each piece of
information to be collected about a switch. Examples of variables include such as number of
packets received, node port status etc. A Management Information Base (MIB) is a collection
of managed objects. SNMP allows a manager and agents to communicate for the purpose of
accessing these objects.
SNMP itself is a simple request/response protocol based on the manager/agent model. The
manager issues a request and the agent returns responses using the following protocol
operations:
120 Chapter 17 Access Control