SNMP overview

SNMP is a set of protocols that describes management data and the protocols for exchanging that data between heterogeneous systems. The protocols include both the description of the management data, defined in the Management Information Base (MIB), and the operations for exchanging or changing that information. By implementing common protocols, management data can be exchanged between different platforms with relative ease.

SNMP defines an architecture that consists of:

Network management applications
Network management agents and subagents
Network elements, such as hosts and gateways

The SNMP network management application can ask agents for specific information about network elements. Conversely, agents can tell the network management application when something happens to one or more network elements. The protocol used between the network management application and agents is SNMP. The transport protocol for SNMP requests is the User Datagram Protocol (UDP).

SNMP defines both the network management data and the ways in which the data is retrieved or changed by the network management application. Examples of network management data include device definitions, counts of packets received at the IP layer, TCP connection data, and so forth. The information about the network elements is stored in the Management Information Base (MIB), which is supported by the SNMP agent and its subagents. A MIB variable (or MIB object) is a specific instance of data in a collection of objects related to a common management area. The collection is called a MIB module. Each MIB object is identified by an object identifier (OID), which is a dotted-decimal value, and by a textual name. For example, the sysUpTime MIB object, which indicates how long ago the SNMP agent initialized, is defined as follows:

Textual name     Object identifier (OID) 
sysUpTime        1.3.6.1.2.1.1.3

The z/OS® Communications Server Network Management agent and subagents, also called SNMP agent and SNMP subagents, support many standard (RFC-based) MIB modules. The SNMP TCP/IP subagent also supports enterprise-specific MIB modules. For information on MIB modules supported by the z/OS Communications Server SNMP agent and subagents, see the SNMP agent capabilities statement, shipped as file /usr/lpp/tcpip/samples/mvstcpip.caps. Additionally, enterprise-specific MIBs are documented in the /usr/lpp/tcpip/samples directory. See TCP/IP subagent for more information on enterprise-specific MIB modules supported by the TCP/IP subagent. For a complete list of MIB objects supported by the SNMP agent and subagents shipped with z/OS Communications Server, see z/OS Communications Server: IP System Administrator's Commands.