Overview of SNMP
Definition
Simplicity: SNMP is applicable to small-scale networks that are sensitive to speed and cost because it uses a polling mechanism and provides basic network management functions. Moreover, most network devices support the UDP packets carrying SNMP messages.
Power: SNMP allows management information exchange between arbitrary devices on a network, so that a network administrator can query information and locate faults on any device.
Purpose
The fast growth of network devices increases network administrators' workloads. In addition, networks' coverage areas are constantly being expanded, making real-time monitoring and fault location of network devices difficult.
- Various devices are located on networks, and the management interfaces that different vendors provide use different standards. This makes network management complex.
SNMP was developed to address these problems. SNMP supports batch network device management and implements unified management regardless of the differences in device types and vendors.
Version Evolution
SNMPv1 is the initial version of the SNMP protocol. It is described in RFC 1157 drafted in May 1990. RFC 1157 provides a systematic method for monitoring and managing networks. However, SNMPv1 cannot ensure the security of networks because it is implemented based on community names and provides only a few error codes.
In 1996, the Internet Engineering Task Force (IETF) released RFC 1901 in which SNMPv2c is defined. SNMPv2c uses GetBulk and Inform operations and provides more error codes and data types (including Counter64 and Counter32).
SNMPv2c still lacks security protection measures, so IETF released SNMPv3. SNMPv3 provides user security module (USM)-based encryption and authentication and a view-based access control model (VACM).
Benefits
Improves administrators' work efficiency. A network administrator can use SNMP to query information, modify information, and locate faults on any device.
Reduces management costs. SNMP provides a basic function set to manage devices that have different management tasks, physical attributes, and network types.
Reduces the impact of feature configuration operations on devices. SNMP is simple in terms of hardware/software installation, packet type, and packet format.
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