Developing Network Management


SNMP.  Simple Network Management Protocol - SNMP is a TCP/IP protocol purpose-built to serve as a communications channel for internetwork management operating at the application layer of the IP stack.  Although SNMP can be directly operated through the command line, it is almost always used through a management application that uses the SNMP communications channel to monitor and control networks.  SNMP has  two basic components a network management station and agents.

Agents are small software modules that reside on managed devices.  They can be configured to collect specific pieces of information on device operations.  Most of the information consists of totals, such as total bytes, total packets, total errors and the like.  Agents can be deployed on a variety of devices.

  • Routers
  • Switches
  • Access Servers
  • Hubs
  • Servers
  • Workstations
  • Printers
  • UPS Power Backup

The idea is to place agents on all network devices and manage things according to the status information sent back.

SNMP is a fairly simple request/response protocol.  It works by having the Network Management System periodically poll the managed devices.  There are three types of polling:

  • Monitor polling - to check which devices are available and trigger an alarm when one is not
  • Threshold polling - to detect when conditions deviate from a baseline number by a percentage greater than allowed (usually plus or minus 10% or 20%) and notify the NMS for review
  • Performance polling - to measure ongoing network performance over longer periods of time and to analyze the data for long term trends and patterns