gtpc1m2i | Transmission Control Protocol/Internet Protocol |
As Transmission Control Protocol/Internet Protocol (TCP/IP) networks have become increasingly diverse and complex with many different types of devices and network nodes connected to them, it has become more challenging to manage them. SNMP is a standard protocol that was developed to provide an effective way to centralize the management of TCP/IP networks. SNMP consists of three major components that communicate with each other to manage and monitor TCP/IP networks:
SNMP is defined by a series of Request for Comments (RFC) documents that describe the specifications for network management including the protocol itself, the definition of data structures, and associated concepts. The architecture for standard TCP/IP network management protocols is defined by the following RFC documents:
Go to http://www.ietf.org for more information about these RFCs and any related extensions.
The SNMP manager consists of a set of applications that monitor all the other nodes (SNMP agents) in the network and send requests for information to SNMP agents in the network. The SNMP manager requests TCP/IP information from the SNMP agents in the network by requesting the variables from each agent's MIB database. The manager also receives and processes unsolicited messages from the agents, which indicate that a significant event has occurred at a specific network node. These unsolicited messages are called traps.
An SNMP agent is an entity on the network that supplies the SNMP manager with TCP/IP network information. An SNMP agent maintains the MIB database of TCP/IP network information pertaining to its network node. The SNMP agent responds to requests from the SNMP manager for information from its MIB and sends traps to SNMP managers when significant events occur.
The MIB is a database of variables and their associated values that is maintained by the SNMP agent about the node on which it resides. The SNMP manager solicits information from the MIB of the SNMP agent. Each piece of information in the MIB database is called an MIB variable. See Appendix G, Management Information Base Variables for a list of all the MIB-II variables supported by the TPF system.
Use the ZSNMP command to display the MIB variables from the TPF system. You can also save the display information to a file. See TPF Operations for more information about the ZSNMP command.
Figure 19 shows a high-level view of the interaction between the three major components of SNMP. Specifically, this figure shows an SNMP agent with its MIB database of TCP/IP networking information being monitored by an SNMP manager. Queries can be issued from an SNMP manager to obtain statistical information about TCP/IP native stack support networks.
Figure 19. Interaction between SNMP Components
Figure 20 shows an example of an SNMP trap message being sent by an SNMP agent to the SNMP managers. When the SNMP agent system loses one of its TCP/IP links, it notifies the SNMP managers that a link went down.