HP Cisco Nexus 5000 Cisco Nexus 5000 Series and Cisco Nexus 2000 Series MIB Qu - Page 2

MIBs and Network Management Send documentation comments to [email protected] To promote interoperability, cooperating systems must adhere to a common framework and a common language, called a protocol. In the Internet-standard management framework, that protocol is the Simple Network Management Protocol (SNMP). The exchange of information between managed network switches and a robust NMS is essential for reliable performance of a managed network. Because some switches have a limited ability to run management software, most of the computer processing burden is assumed by the NMS. The NMS runs the network management applications, such as Data Center Network Manager, that present management information to network managers and other users. In a managed switch, specialized low-impact software modules, called agents, access information about the switch and make it available to the NMS. Managed switches maintain values for a number of variables and report those, as required, to the NMS. For example, an agent might report such data as the number of bytes and packets sent or received by the switch or the number of broadcast messages sent and received. In SNMP, each of these variables is referred to as a managed object. A managed object is anything that can be managed or anything that an agent can access and report back to the NMS. All managed objects are contained in the MIB, which is a database of the managed objects. An NMS can control a managed switch by sending a request to an agent of that managed switch, requiring the switch to change the value of one or more of its variables. The managed switches can respond to requests such as set or get. The NMS uses the set request to control the switch. The NMS uses the get requests to monitor the switch. The set and get requests are synchronous events, which means that the NMS initiates the activity, and the SNMP agent responds. The managed switch can send asynchronous events, or SNMP notifications, to the NMS to inform the NMS of some recent event. SNMP notifications (traps or informs) which are included in many MIBs, and allow the NMS to send get requests to the managed switches less frequently. This section includes the following topics: • Accessing MIB Variables Through SNMP, page 2 • SNMP Traps and Informs, page 3 • Interpreting the MIB Structure, page 3 Accessing MIB Variables Through SNMP You can access the Cisco MIB variables through SNMP. The SNMP system consists of three parts: the SNMP manager, the SNMP agent, and the MIB. You can compile Cisco MIBs with your network management software. If SNMP is configured on a switch, the SNMP agent responds to MIB-related queries sent by the NMS. Table 1 describes the SNMP operations. Table 1 SNMP Operations Operation get-request get-next-request get-bulk2 Description Retrieves a value from a specific variable. Retrieves the value following the named variables. Often used to retrieve variables from within a table.1 Retrieves large blocks of data, such as multiple rows in a table, which would otherwise require the transmission of many small blocks of data. Cisco Nexus 5000 Series and CiscoNexus 2000 Series MIB Quick Reference 2 OL-16784-01