Unicenter

Overview

Simple Network Management Protocol (SNMP) is an industry standard protocol that came into existence to manage the network elements (routers, switches, desktops, firewalls, wireless devices etc) on an IP network. SNMP helps automate the monitoring and management across diverse, multi-technology networks, ensuring the availability and performance of critical network devices and services essential to run your business. SNMP is an application layer protocol and in most of the deployments functions over User Datagram protocol (UDP).SNMP has grown from unsecure SNMP v1 to SNMP v3 which provides enhanced security in terms of authentication. SNMP today is the defacto standard management protocol in the networking.

Few Key Terms related to SNMP

Network Management Station/System or the Manager

Network Management Station/System or the Manager provides tools to manage the network. The network management system issues requests/polls for a devices state and devices return responses.

An Agent

An agent resides on a managed device. The agent collects data from the managed device and translates that information into a format that can be passed over the network using SNMP.

Managed Network Elements

A managed network element can be any piece of network equipment that sits on your network and is SNMP compliant.

Managed object

A managed object is a characteristic of a network element that can be managed. For example, a list of processes running in a server operating system , memory usage, available memory, packet errors etc. Managed objects can be a single object instance or multiple, related instances.

Management information base (MIB)

A MIB is a collection of managed objects residing in an information store. Collections of related managed objects are defined in specific MIB modules. In simplest terms, the MIB is a collection of information that is organized in a standard structure. Each piece of information within the MIB can be referred to by means of an Object ID (OID), a unique string of numbers and periods. When an Agent notifies the manager of an event, the notification includes an OID that identifies the type of event and data that identifies specifically what has occurred. OID being such an important part of identifying an event, it is absolutely essential that no two vendors use the same OID to describe different events. Standards are in places that prevent this from occurring.

Protocol Data Units

Agents send alerts to Managers using SNMP Trap PDUs. The PDU contains the IP Address of the sender, the OID that is associated with the alert being passed, and the value assigned to that OID. This information tells the NMS exactly what it is being notified about and where the notification originated. The Manager sends SNMP GetRequests to the Agent to gather information from the MIB. It can also send SNMP SetRequests to modify different MIB attributes if necessary. The Agent sends an SNMP GetResponse to the Manager after acting on both GetRequests and SetRequests. If the Manager does not receive this response, it assumes that the action was not taken.