Simple Network Management Protocol (SNMP) is a network protocol that is native to IP networks and compatible with most network devices. SNMP monitoring provides a standardized way for network engineers and admins to gather information about networking equipment and helps ensure that a company’s network is running smoothly. Many network monitoring tools rely on SNMP to gain visibility into network infrastructure, such as routers, switches, and firewalls.
Components of SNMP Monitoring
SNMP provides a flexible framework, with several components working together to enable network engineers to monitor the health and performance of devices:
• SNMP Manager
The server, or other external process, that will poll network devices for information and collect the responses. SNMP Managers may also be referred to as Network Management Stations (NMSs).
• SNMP Agent
The software client that is pre-installed on most network devices. The SNMP Agent will store information about device status and relay this to the SNMP Manager when polled.
• Managed Device
A network device on which the SNMP Agent is installed, enabled, and configured. Routers, switches, firewalls, and wireless access points are examples of devices that you can manage via SNMP.
• Management Information Base (MIB)
A dictionary of hierarchically structured information from a device. Each entry in a MIB contains the object identifier (OID) and its human-readable definition.
• Object Identifier (OID)
An address on a device that represents a specific piece of information. OIDs can represent any measurable information such as uptime, fan speed, or temperature, as well as configurable elements like maximum bandwidth or device name.
And How it Works?
• Activation vs. Installation
On most network devices, SNMP capabilities are pre-installed and ready to use. In instances where this isn’t the case, you can usually turn the SNMP functionalities on and off in the factory settings. Sometimes, by default, these SNMP capabilities are turned off, so check the settings when you first acquire your device.
There might be compatibility issues when implementing SNMPv3, which can be addressed by implementing an RTU translator. The same applies to network equipment issues. Say some of your hardware is old and isn’t compatible with SNMP. Installing an RTU establishes SNMP monitoring on the chosen device, enabling the sending of traps in case of errors.
• File Storage
Once active, SNMP functionalities are ongoing and uninterrupted, set to fire up as soon as the operating system is turned on. Each operating system will store executable files in a different place, and possibly under a different name, so it’s worth getting familiar with how your operating system does this. Each network server will have multiple .mib files, created when the SNMP software agent is activated. For Windows, these files are under the Windows/System32 directory, while on Linux they’re in /usr/share/snmp/mib.
• On-Premises vs. In the Cloud
SNMP managers comprise three key elements: a datastore, a user interface, and a collector. If you’re using a cloud-based network monitor, ensure the collector is installed; however, the datastore and interface software will be located remotely.
Conversely, an on-premises installation entails having the key components installed on a server. You have the choice of establishing your datastore either as a SQL database or as a file.
• Initial Request
Once all the agents are active and operating correctly, they can reply to a collector’s Get request. The process of installation is fully complete when the first request is broadcast and picked up by the agents. After that, the interface software will put together an inventory based on the SNMP responses, eradicating the need to manually map your network. Now you’re ready to start monitoring and managing the health of your devices, as well as the overall network.