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This chapter describes the Cisco Systems private, or local, Management Information Base (MIB) for the Cisco MDS 9000 Family devices. The Cisco MIBs are provided with all Cisco software releases and with CiscoWorks router management software. The MIB files contain variables that can be set or read to provide information on network devices and interfaces.
This chapter includes general information on MIBs and their role in network management, procedures for obtaining Cisco MIBs, and a list of the MIBs supported by the Cisco MDS 9000 Family devices.
The Cisco MDS 9000 Family MIB Reference lists the MIB variables that are proprietary to these Cisco devices. However, many other Internet-standard MIBs are supported by Cisco agents. These standard MIBs are defined in documents called Requests for Comments (RFCs). To find specific MIB information, you must examine the Cisco proprietary MIB structure and the standard RFC MIBs supported by Cisco.
From the perspective of a network manager, network management takes place between two major types of systems: those in control, called managing systems, and those observed and controlled, called managed systems. The most common managing system is called a network management system (NMS). Managed systems can include hosts, servers, or network components such as routers or intelligent repeaters.
To promote interoperability, cooperating systems must adhere to a common framework and a common language, called a protocol. In the Internet Network Management Framework, that protocol is the Simple Network Management Protocol (SNMP).
The exchange of information between managed network devices and a robust NMS is essential for reliable performance of a managed network. Because some devices 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 Fabric Manager, that present management information to network managers and other users.
In a managed device, specialized low-impact software modules, called agents, access information about the device and make it available to the NMS. Managed devices 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 in and out of the device, or the number of broadcast messages sent and received. In the Internet Network Management Framework, each of these variables is referred to as a managed object. A managed object is anything that can be managed, anything that an agent can access and report back to the NMS. All managed objects are contained in the Management Information Base (MIB), a database of the managed objects.
An NMS can control a managed device by sending a message to an agent of that managed device requiring the device to change the value of one or more of its variables. The managed devices can respond to commands such as set or get commands. The set commands are used by the NMS to control the device. The get commands are used by the NMS to monitor the device.
The MIB structure is logically represented by a tree hierarchy. The root of the tree is unnamed and splits into three main branches: Consultative Committee for International Telegraph and Telephone (CCITT), International Organization for Standardization (ISO), and joint ISO/CCITT.
These branches and those that fall below each category have short text strings and integers to identify them. Text strings describe object names, while integers allow computer software to create compact, encoded representations of the names.
Each MIB variable is assigned an object identifier. The object identifier is the sequence of numeric labels on the nodes along a path from the root to the object. For example, the MIB variable tftpHost is indicated by the number 1. The object identifier for tftpHost is iso.org.dod.internet.private.enterprise.cisco.workgroup products.stack group.tftp group.tftpHost variable or 1.3.6.1.4.1.9.5.1.5.1. The last value is the number of the MIB variable tftpHost.
You can access the Cisco MIB variables through the SNMP, an application-layer protocol designed to facilitate the exchange of management information between network devices. The SNMP system consists of three parts: SNMP manager, SNMP agent, and MIB.
The SNMP manager can be part of a network management system (NMS), and the SNMP agent can reside on a networking device such as a switch. You can compile the Cisco MIB with your network management software. If SNMP is configured on a device, the SNMP agent responds to MIB-related queries being sent by the NMS.
The SNMP agent gathers data from the MIB. Then, the agent can send traps, or notifications of certain events, to the manager. The SNMP manager uses information in the MIB to perform the operations described in Table 1-1.
Table 1-1 SNMP Manager Operations
| 1With this operation, an SNMP manager does not need to know the exact variable name. A sequential search is performed to find the needed variable from within the MIB.
2The get-bulk command only works with SNMP version 2. |
The syntax describes the format of the information, or value, that is returned when you monitor or set information in a device with a MIB variable.
Cisco MDS 9000 Family MIBs are defined with the SNMPv2 SMI. Some examples of SNMPv2 syntax are:
A nonnegative integer that increases until it reaches some maximum value. After reaching the maximum value, it rolls back to zero. For example, the variable locIfipInPkts counts the number of IP protocol input packets on an interface.
A printable ASCII string. It is typically a name or description. For example, the variable netConfigName provides the name of the network configuration file for a device.
A numeric value. It can be an actual number—for example, the number of lost IP packets on an interface. It also can be a number that represents a nonnumeric value. For example, the variable tsLineType returns the type of terminal services line to the SNMP manager. A 2 indicates a console line; a 3 indicates a terminal line; and so on.
An integer from -232 to 232-1.
The variable hostConfigAddr indicates the IP address of the host that provided the host configuration file for a device.
Defined in RFC 1443 as the value of the MIB-II sysUpTime object at which a specific event occurred.
A nonnegative integer that counts the hundredths of a second that have elapsed since an event. For example, the variable loctcpConnElapsed provides the length of time that a TCP connection has been established.
This variable can represent one of the following four states: read-create, read-write, read-only, and not-accessible.
You cannot read or write to this variable. Entry statements are typically among those variables that are not accessible.
This specifies a tabular object that can be read, modified, or created as a new row in a table.
This variable can be used only to monitor information.
You can read or modify this variable.
When network management protocols use names of MIB variables in messages, each name has an appended suffix. This suffix is called an instance identifier. For simple variables, the instance identifier 0 refers to the instance of the variable with that name. A MIB also can contain tables of related variables.
An excerpt of the information on the VSAN table (known as vsanTable) from the associated MIB file follows:
In the example, the vsanTable contains two variables: vsanIndex and vsanName. (There are more values in the real vsanTable.) The index for this table is the ID of the VSAN, or vsanIndex. With n number of VSANs available, n rows are available in the table.
The Cisco MIB is a set of variables that are private extensions to the Internet standard MIB II. The MIB II standard is documented in Request for Comment (RFC)1213, Management Information Base for Network Management of TCP/IP-based Internets: MIB-II.
The Cisco MIB is described by a number of MIB files, which can be obtained by File Transfer Protocol (FTP) from the Cisco server.
Cisco agents support many other Internet-standard MIBs. These standard MIBs are defined in RFC publications. To find specific MIB information, you must examine the Cisco proprietary MIB structure and the standard RFC MIBs supported by Cisco.
If your NMS is unable to get requested information from a managed device such as a Cisco router, the MIB that allows that specific data collection might be missing. Typically, if an NMS cannot retrieve a particular MIB variable, either the NMS does not recognize the MIB variable, or the agent does not support the MIB variable. If the NMS does not recognize a specified MIB variable, you might need to load the MIB into the NMS, usually with a MIB compiler. For example, you might need to load the Cisco Workgroup MIB or the supported RFC MIB into the NMS to execute a specified data collection. If the agent does not support a specified MIB variable, you must find out what version of system software you are running. Different software releases support different MIBs.
Cisco public MIB files are organized into two directories: SNMPv1 MIBs are in the v1 directory and SNMPv2 MIBs are in the v2 directory. (Cisco MDS 9000 Family MIBs are all in the v2 directory.) Get a description of the files by retrieving the following:
Many MIBs use definitions that are defined in other MIBs. These definitions are listed in the IMPORTS section near the top of the MIB.
If MIB B imports a definition from MIB A, some MIB compilers require you to load MIB A prior to loading MIB B. If you get the MIB loading order wrong, the MIB compiler might complain about what was imported claiming it is undefined or not listed in IMPORTS. If this happens, look at the loading order of the MIB definitions from the IMPORTS of the MIB. Make sure that you have loaded all the preceding MIBs first.
Here is a list of MIBs from which many other MIBs import definitions. The MIBs are listed in the order in which you should load them:
If you load the MIBs in this order, you can eliminate 95 percent of your load-order definition problems.
You can load most other MIBs (those not listed here) in any order.
You can access the Cisco MIB files in either of the following ways:
To access the Cisco public MIBs using FTP, follow these steps:
Step 2 Navigate to ftp://ftp.cisco.com/pub/mibs/supportlists/.
Step 3 Select the appropriate system.
Step 4 Select and save the MIBs you need to download.
To access MIB files using your Web browser, follow these steps:
Step 2 You see Cisco MIBs supported by products.
Step 3 Select the appropriate system.
Step 4 Select and save the MIBs you need to download.
The following are the MIBs supported by the Cisco MDS 9000 Family devices:
The ifRcvAddressTable is not supported from this MIB.
The following groups are supported from this MIB:
Posted: Tue Jul 1 23:29:49 PDT 2003
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