SNMP

The Simple Network Management Protocol (SNMP) has undergone a remarkable evolution since its inception in the late 1980s. Initially conceived to address the need for a standardized protocol for managing the increasing number of devices on the Internet, Simple Network Management Protocol's journey began with the establishment of the Network Management Working Group (NMWG) by the Internet Engineering Task Force (IETF). The first standardized iteration, SNMPv1, laid down the foundational framework for network management, introducing a manager-agent model and defining basic operations for querying and configuring managed devices. This version was documented in RFC 1157 in 1990. Request for Comments (RFC) describes a series of documents that were put up for discussion during the development of the Internet and today can generally be regarded as reviewed technical specifications. 

However, SNMPv1 had its limitations like lacking robust authentication and encryption., prompting the development of SNMPv2, which was documented in RFC 1441 in 1993. SNMPv2 aimed to address some of the shortcomings of the earlier version but encountered interoperability challenges due to its fragmented nature. Despite these challenges, SNMPv2c, a variant of SNMPv2, emerged as the widely adopted standard, maintaining the community-based security model of its predecessor. 

A significant milestone in the evolution of Simple Network Management Protocol was the introduction of SNMPv3, documented in RFC 3410 in 2002. SNMPv3 marked a substantial advancement in the protocol's security features, incorporating a comprehensive security framework that included authentication, encryption, and access control mechanisms. These enhancements were designed to safeguard SNMP messages and ensure data integrity. 

Simple Network Management Protocol (SNMP) offers a standardized protocol for monitoring and managing network devices and systems. This protocol facilitates the collection and organization of information about managed devices, enabling tasks such as configuration changes, troubleshooting, and the generation of alerts or notifications about network events. At the heart of SNMP's architecture lies the client-server model, which delineates roles between SNMP managers and agents, facilitating efficient network management and monitoring. A SNMP manager, also known as a network management station (NMS), assumes a pivotal role in this architecture. It is tasked with initiating communication by sending queries to SNMP agents embedded within network devices. These queries are aimed at retrieving or modifying information about the device's performance, health, and configuration. The SNMP manager is essentially the command centre, responsible for collecting, processing, and analysing data from across the network to ensure optimal operation and swift response to any anomalies. 

Conversely, SNMP agents reside on managed devices, such as routers, switches, and servers as well as some devices implementing Industrial Ethernet Protocols like PROFINET or Ethernet/IP. The SNMP agents act as representatives of these devices within the Simple Network Management Protocol framework. Each agent maintains a Management Information Base (MIB) — a database containing metrics and operational statistics of the host device. Upon receiving a query from the SNMP manager, the agent retrieves the requested information from its MIB and sends it back, thus enabling the manager to maintain an up-to-date view of the network's status. Simple Network Management Protocol messages, or protocol data units (PDUs), are meticulously structured to maintain consistent and reliable communication between managers and agents. These messages comprise headers that carry protocol-specific information, data payloads containing the management information, and, optionally, security parameters. 

One of the most crucial elements of Simple Network Management Protocol operations is the already mentioned Management Information Base (MIB), a database that describes the managed objects within a network device. The MIB enables Simple Network Management Protocol managers to query agents for specific information or to set parameters on the devices they manage. It is structured hierarchically, with each managed object identified by a unique Object Identifier (OID). This hierarchical structure facilitates the organization and accessibility of managed objects within the MIB, enabling efficient communication and management between Simple Network Management Protocol managers and agents. 

Simple Network Management Protocol's operations are encapsulated in a set of basic commands as follow:  

GET

Utilized by the Simple Network Management Protocol manager to retrieve one or more values from managed devices. This operation allows for the monitoring of specific parameters within the network, ensuring that performance metrics are within expected thresholds. 

SET

Enables the Simple Network Management Protocol manager to modify the value of an object on the managed device. This command is crucial for making configuration changes remotely, allowing for efficient management of network settings without the need for direct physical access to the devices. 

GETNEXT/GETBULK

Designed to streamline data retrieval by allowing the SNMP manager to request the next object in the MIB tree or to fetch large volumes of data in a single request, respectively. These operations are particularly useful for collecting comprehensive datasets from devices, facilitating thorough network analysis and monitoring. 

TRAPS/INFORMS

Unsolicited messages sent from SNMP agents to the Simple Network Management Protocol manager to notify it of significant events or conditions on the network devices. While traps do not require acknowledgment from the manager, informs do, providing a mechanism for confirmation that the notification was received and processed. 

RESPONSE

Used by SNMP agents to reply to requests from the SNMP manager. This operation ensures that the manager receives the requested data or confirmation of actions taken, completing the communication cycle essential for effective network management. 

Simple Network Management Protocol operates predominantly at the Application Layer (Layer 7) of the OSI model, which is crucial for enabling the high-level functions required for network management. SNMP's reliance on the User Datagram Protocol (UDP) or, less commonly, the Transmission Control Protocol (TCP) for transport, places it within the Transport Layer (Layer 4) for its communication needs. This dual-layer operation underscores SNMP's role in leveraging both application and transport layer services to perform its critical functions. The versatility of Simple Network Management Protocol extends to its compatibility with various network topologies prevalent in industrial settings, including bus, star, ring, and mesh configurations. 

The Simple Network Management Protocol (SNMP) is a versatile tool used across various types of networks, including Fieldbus networks, industrial Ethernet networks, and Industrial Internet of Things (IIoT) environments. 

SNMP in Fieldbus networks 

SNMP provides critical network diagnostics in Fieldbus networks, particularly through Ethernet switches, whether standalone or integrated within field devices. This role involves accessing and utilizing data within these switches to monitor and manage network health and performance. By doing so, SNMP enables network administrators to maintain reliable and efficient communication across the network, ensuring that any potential issues are quickly identified and rectified. 

SNMP in Industrial Ethernet networks 

In the realm of industrial Ethernet networks, SNMP continues to serve an invaluable role by collecting data related to network alterations and determining the status of network-connected devices. This functionality is pivotal for IT professionals monitoring the health of all managed devices and the applications they support. The data gleaned from SNMP monitoring allows for the prompt identification of performance bottlenecks or network failures, facilitating swift corrective actions and maintaining operational continuity. 

SNMP in IIoT environments 

The application of SNMP also extends into the Industrial Internet of Things (IIoT) where it is instrumental in monitoring the status and performance of various devices and assets. Through integration with IoT platforms SNMP allows administrators to configure such devices remotely. This integration ensures that SNMP can seamlessly communicate with a broad range of IoT devices and assets, enabling comprehensive monitoring and management of these elements within an IIoT framework. 

As a manufacturer of market-leading multi-protocol network interfaces for industrial communication, which can communicate via all common fieldbus, Industrial Ethernet and IIoT protocols and technologies by simply reloading the protocol firmware, Hilscher's netX SoCs, embedded modules and PC cards are also capable of mapping SNMP. 

The same applies to Hilscher's netFIELD ecosystem, which represents a holistic solution portfolio for the Industrial Internet of Things - from the sensor to the cloud. The netFIELD product family consists of powerful edge gateways, a comprehensive edge management platform in the cloud, which is used for the efficient remote management of the edge devices, and turnkey application containers that focus on communication applications in line with Hilscher's core expertise.