SNMP Overview
SNMP (Simple Network Management Protocol) provides a network monitoring mechanism that collects state information from various network devices and components. The protocol enables you to monitor the RBFS network and detect network faults on remote devices.
SNMP can monitor interfaces, CPU usage, temperature of the device, bandwidth usage, and so on. For example, if an interface goes down on one of the devices, SNMP can quickly alert the change.
Understanding RBFS SNMP Implementation
The RBFS SNMP implementation allows retrieving system state information using the Protocol Data Unit (PDU) from various network components. SNMP defines system objects in Management Information Bases (MIBs), where each object forms a Protocol Data Unit (PDU).
A device that is SNMP enabled is known as SNMP agent. SNMP agent collects information from various devices and components and stores the data within MIB. An SNMP agent includes several objects such as interfaces and routing tables which can be interacted with. Every object has a unique identifier which is known as OID (Object Identifier). OIDs provide a unique identity for managed objects in an MIB hierarchy.
RBFS implements the SNMP daemon (snmpd) that maps the operational state API to SNMP MIBs for retrieving system state data.
SNMP Operations
SNMP allows performing various operations that include GET for retrieving data, SET for modifying data, TRAP for notifying an event and so on. These operations provide management access to the MIB hierarchy.
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GET: The SNMP GET operation retrieves data from the managed device’s MIB.
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GETNEXT: The GETNEXT operation retrieves data for the next object from the tree of objects on the device.
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SET: The SNMP SET operation allows modifying data for a device.
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TRAP: Event notification that is not requested.
| RBFS does not currently support the SNMP SET operation. |
Supported SNMP MIBs
Management Information Base (MIB) is a collection of data that is organized hierarchically. You can define an MIB mapping for the supported MIBs. This MIB mapping provides a way to retrieve the required state information using the Operational State API or any other RBFS API or Prometheus.
Currently, RBFS supports two SNMP MIBs: the Interface MIB and the Host Resources MIBs.
Host resource MIB: Host resource MIB collects and provides information for host computer resources.
Interfaces MIB: Interfaces MIB retrieves information about the state of interfaces in devices.
System MIB: Collects and provides information about the device itself. The retrieved information includes the assigned system name, hardware platform details, and the installed network operating system software version.
Supported SNMP Versions
RBFS supports the SNMP version 2c and SNMP version 3. SNMP version 3 provides support for authentication and encryption and the data can be accessed after capture only by authorized users. You must choose either version 2c or version 3 before configuring other functionalities.
Information about SNMP v2c and v3
SNMP v2c allows access control through Communities, but the community information is not protected. Anyone with the community name can access all the information available for that community.
SNMP v3 provides a higher level of security using authentication and privacy protocols. RBFS supports the user-based security model defined in RFC 3414.
The user credentials verify the authenticity and integrity of the message by adding message authentication codes (MACs) to the SNMP packet. The privacy protocol allows for the encryption of the transmitted data.