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This appendix contains information on how to modify existing MIB files and establish new MIB files, as well as a brief example of MIB objects and their usage with CiscoWorks polling capabilities.
For more detailed information on MIB objects, refer to the Cisco Management Information Base (MIB) User Quick Reference. For a list of MIB reference sources relating to building MIB object structure, refer to Appendix D, "References and Recommended Reading."
For purposes of consistency, this manual uses the term object as a replacement for such terms as MIB objects, MIB object instances, and so on. Other Cisco publications may use different terms, but they can be used interchangeably.
There are many MIB objects that can help you to manage your network. All objects are documented in either the RFC standard or a vendor specific MIB (for example, the Cisco MIB). Here are a few to consider:
The textual MIB files must be written in the ASN.1 subset format described in RFC 1212. This guide does not describe all of the aspects of the ASN.1 language.
A MIB is organized into a tree structure consisting of labeled nodes. A complete object identifier is built by traversing the tree from the root node, collecting labels as each node is passed. The root of the MIB tree is iso(1).
Except for the MIB tree root iso(1), all nodes in the tree must have the parent node defined before a child node may be defined. Upper level nodes (those above mib(1)) may be most conveniently defined with the statement:
MibName is an arbitrary name. The numbers in parentheses are preassigned node numbers. The above statement is interpreted as: mgmt is the beginning of a subtree (called MIBName) under internet which is under dod which is under org which is under iso.
Additional subtrees below mgmt can be defined using OBJECT IDENTIFIER statements as follows:
Child Node OBJECT IDENTIFIER
::= { ParentNode ChildNodeNumber }
For example, to define mib (an object type) as a child of mgmt and assign a node number of 1 do the following:
mib OBJECT IDENTIFIER ::= { mgmt 1 }
Most object types in a MIB should be defined using the OBJECT-TYPE macro. The following are the basic structure elements and format of an object type using the OBJECTTYPE macro:
ObjectDescriptor OBJECT-TYPE SYNTAX ASN1_Type ACCESS AccessType STATUS StatusType ::= ObjectIdentifier
An example of defining an OBJECT-TYPE macro with the name atNetAddress would be:
atNetAddress OBJECT-TYPE
SYNTAX NetworkAddress
ACCESS read-write
STATUS mandatory
:= { atEntry 3 }
MIB trees must define the parentage of every branch from terminal object IDs to the iso(1) tree root. All trees must have the same root (iso(1) is the recommended root) in order to determine how one MIB tree relates to another.
The MIB object set read by CiscoWorks at the time it is started defines the objects that can be monitored and collected in the database for future analysis. At startup, CiscoWorks looks for the files mib.bin and mib.alias in the CiscoWorks directory $NMSROOT/etc/mibs. These files define the MIB object set and the aliases that will be used for polling and data collection. These two files and alias.gen, alias.master, and the mib source files (*.mib) comprise the set of MIB-related files necessary for the operation of CiscoWorks.
Several MIB source files are shipped with CiscoWorks:
The alias.master file contains the list of aliases upon which CiscoWorks depends. It is located in $NMSROOT/etc/mibs.
The Cisco private MIB object file, cisco.mib, is located in the CiscoWorks directory $NMSROOT/etc/mibs. This section lists the Cisco private MIB objects that have been introduced after Software Release 8.0.
The following list describes the objects introduced with Software Release 8.1:
actAge
ipCkAccountingTable
ipckactSrc
ipckactDst
ipkactPkts
ipckactByts
ckactAge
The following list describes the objects introduced with Software Release 8.2:
writeMem
writeNet
busyPer
avgBusy1
avgBusy5
idleCount
idleWired
locIfCarTrans
locIfReliab
locIfDelay
locIfLoad
locIfCollisions
tsLineNoise
dnAreaTable
dnACost
dnAHop
dnAIfIndex
dnANextHop
dnAAge
dnAPrio
vinesInput
vinesOutput
vinesLocaldest
vinesForwarded
vinesBcastin
vinesBcastout
vinesBcastfwd
vinesNotlan
vinesNotgt4800
vinesNocharges
vinesFormaterror
vinesCksumerr
vinesHopcout
vinesNoroute
vinesEncapsfailed
vinesUnkown
vinesIcpIn
vinesIcpOut
vinesMetricOut
vinesMacEchoIn
vinesMacEchoOut
vinesEchoIn
vinesEchoOut
The following list describes the objects introduced with Software Release 8.3:
bufferHgsize
bufferHgTotal
bufferHgFree
bufferHgMax
bufferHgHit
bufferHgMiss
bufferHgTrim
bufferHgCreate
locIfInputQueueDrops
locIfOutputQueueDrops
ipNoaccess
actCheckPoint
tsMsgTtyLine
tsMsgIntervaltim
tsMsgDuration
tsMsgTest
tsMsgTmpBanner
tsMsgSend
dnIfTable
dnIfCost
The following list describes the objects introduced with Software Release 9.0:
netConfigProto
hostConfigProto
sysConfigAddr
sysConfigName
sysConfigProto
sysClearARP
sysClearInt
envPresent
envTestPt1Descr
envTestPt1Measure
envTestPt2Descr
envTestPt2Measure
envTestPt3Descr
envTestPt3Measure
envTestPt4Descr
envTestPt4Measure
envTestPt5Descr
envTestPt5Measure
envTestPt6Descr
envTestPt6Measure
locIfDescr
locIfPakmon
The following list describes the objects introduced with Software Release 9.1:
envTestPt4MarginPercent
envTestPt5MarginPercent
envTestPt6MarginPercent
envTestPt1last
envTestPt2last
envTestPt3last
envTestPt4last
envTestPt5last
envTestPt6last
envTestPt1MarginVal
envTestPt2MarginVal
envTestPt3MarginVal
envTestPt4MarginVal
envTestPt5MarginVal
envTestPt6MarginVal
envTestPt1warn
envTestPt2warn
envTestPt3warn
envTestPt4warn
envTestPt5warn
envTestPt6warn
envFirmVersion
envTechnicianID
envType
envBurnDate
envSerialNumber
locIfSlowInPkts
locIfSlowOutPkts
locIfSlowInOctets
locIfSlowOutOctets
locIfFastInPkts
locIfFastOutPkts
locIfFastInOctets
locIfFastOutOctets
locIfotherInPkts
locIfotherOutPkts
locIfotherInOctets
locIfotherOutOctets
locIfipInPkts
locIfipOutPkts
locIfipInOctets
locIfipOutOctets
locIfdecnetInPkts
locIfdecnetOutPkts
locIfdecnetInOctets
locIfdecnetOutOctets
locIfxnsInPkts
locIfxnsOutPkts
locIfxnsInOctets
locIfxnsOutOctets
locIfclnsInPkts
locIfclnsOutPkts
locIfclnsInOctets
locIfclnsOutOctets
locIfappletalkInPkts
locIfappletalkOutPkts
locIfappletalkInOctets
locIfappletalkOutOctets
locIfnovellInPkts
locIfnovellOutPkts
locIfnovellInOctets
locIfnovellOutOctets
locIfapolloInPkts
locIfapolloOutPkts
locIfapolloInOctets
locIfapolloOutOctets
locIfvinesInPkts
locIfvinesOutPkts
locIfvinesInOctets
locIfvinesOutOctets
locIfbridgedInPkts
locIfbridgedOutPkts
locIfbridgedInOctets
locIfbridgedOutOctets
locIfsrbInPkts
locIfsrbOutPkts
locIfsrbInOctets
locIfsrbOutOctets
locIfchaosInPkts
locIfchaosOutPkts
locIfchaosInOctets
locIfchaosOutOctets
locIfpupInPkts
locIfpupOutPkts
locIfpupInOctets
locIfpupOutOctets
locIfmopInPkts
locIfmopOutPkts
locIfmopInOctets
locIfmopOutOctets
locIflanmanInPkts
locIflanmanOutPkts
locIflanmanInOctets
locIflanmanOutOctets
locIfstunInPkts
locIfstunOutPkts
locIfstunInOctets
locIfstunOutOctets
locIfspanInPkts
locIfspanOutPkts
locIfspanInOctets
locIfspanOutOctets
locIfarpInPkts
locIfarpOutPkts
locIfarpInOctets
locIfarpOutOctets
locIfprobeInPkts
locIfprobeOutPkts
locIfprobeInOctets
locIfprobeOutOctets
flashSize
flashFree
flashcontoller
flashcard
flashVPP
flashErase
flashEraseTime
flashEraseStatus
flashToNet
flashToNetTime
flashToNetStatus
netToFlash
netToFlashTime
netToFlashStatus
flashStatus
flashEntries
flashDirName
flashDirSize
flashDirStatus
Since many networks are built with equipment from various vendors, and there are custom objects that you as a network manager may want to monitor; you can add these non-Cisco custom MIBs to the standard object set.
CiscoWorks uses two files to define how it accesses MIB object information from devices. The first, mib.bin, is a database of all the objects currently defined in the MIB source files. The second file is the mib.alias file. This file allows Cisco Systems to define a protocol independent application environment.
The mib.alias file also allows you to assign your own names to existing MIB objects. For instance, you could assign the name UpTimeInterval to the MIB object sysUptime. You could also assign several names to the same MIB object. The mib.alias file provides the translation matrix for the object information you want to collect.
If you want to collect custom MIB information from non-Cisco SNMP devices in your network, follow the steps below to use the makemib command to create new mib.bin and mib.alias files for your installation:
hostname% makemib
When the makemib process finishes, you are ready to start CiscoWorks.
Makemib first invokes mibbld to generate the mib.bin file and the alias.gen file, and then invokes the aliaschk program to check the alias.gen file. It then combines the alias.gen and alias.master files to form the mib.alias file. See Figure A-1.
Figure A-1 CiscoWorks MIB Build Process
The process of expanding the MIB object set starts with a series of files supplied by the vendors of the various network products. These files define the MIB objects and can be edited with any standard text editor as long as you conform to the concise MIB format. You can collect as many files as you like. The file specification must end in .mib.
Use the following command to start makemib:
MasterAlias is the master alias file (default: alias.master).
FinalAlias is the final alias file (default: mib.alias).
Options are described in Table A-1.
Table A-1 Makemib Command Options
| Option | Description |
|---|---|
| --f MibFile | The MIB file to be processed is specified by filename MibFile (default *.mib). |
| --o OutMib | The name of the output file for the MIB binary file (default mib.bin). |
| --p PathToMibs | Process all MIB files found in the directory specified by the path name PathToMibs (default $NMSROOT/$MIBDIR) |
| --a AliasFile | The name of output file for the aliases (default alias.gen) |
| --w WarnLevel | Set the warning message level at the level specified by WarnLevel. A level of 0 suppresses all warning messages (including "unknown variable type," which are desirable). The default setting is 1. Mibbld will issue warning and error messages regarding syntax errors, bad keywords, etc. For this reason it is wise to run with the warning level set to 1 or greater. |
| --t | Display MIB table after processing (on stdout). |
| --n | Disable alias generation. |
| --v | Display copyright and version information (on stdout). |
| --h | Display help information (on stderr). |
Invoking makemib completes the process in a single command step. You can, however, invoke the mibbld and aliaschk programs individually instead of invoking the makemib command. These programs are described later in this chapter under their individual headings.
Cisco Systems recommends that you use the makemib command.
MIB aliases are used by CiscoWorks to create protocol independent MIB objects. The mib.alias file defines a name in terms of a MIB object name and a protocol. Aliases also allow one or more protocol specific object identifiers to be associated with a single MIB object. Currently, only SNMP is supported.
The mib.alias file is an ASCII file. Each alias entry takes the following general format:
The ObjectID may be in either numeric or textual form, but must be fully qualified. MIB trees must define the parentage of every branch from terminal object IDs to the iso(1) tree root. All trees must have the same root. Iso(1) is the recommended root. As a side effect of ASN.1 object identifier encoding, the first two subidentifiers are compressed into a single numeric value. Thus, iso(l) -- org(3) becomes 43. rather than 1.3. This convention is followed when specifying a numeric object identifier within an alias entry.
For uniformity, iso(l) -- org(3) is also compressed to isoorg in a textual object identifier. Note that in actual application, each textual subidentifier must be introduced with the underbar delimiter (_), even the first subidentifiers (such as _isoorg).
An example of a portion of a mib.alias file appears below:
UpTime { SNMP::43.6.1.2.1.1.3 }
ItsTime {
SNMP::_isoorg_dod_internet_mgmt_mib_system_sysUpTime }
EgpNeighbor { SNMP::43.6.1.2.1.8.5.1.1,
SNMP::43.6.1.2.1.8.5.1.2 }
RouteMetric {
SNMP::43.6.1.2.1.4.21.1.3,
SNMP::43.6.1.2.1.4.21.1.4,
SNMP::43.6.1.2.1.4.21.1.5,
SNMP::43.6.1.2.1.4.21.1.6
}
If more than one object identifier is listed for a given alias, the order in which the IDs are listed implies the order in which CiscoWorks will search for the ID.
Comments can be included in the MIB alias file by introducing the comment with two dashes (--). For example:
-- This is a comment.
The makemib command builds the alias entries in alias.gen and then concatenates alias.gen and alias.master into mib.alias. It generates a name that is unique for each object by prefixing the mib file identifier (defined within the mib file) to the object name with a dash (-). If the MIB file name were new.mib, the file name identifier in this file were NEW-MIB and the object name were newMibVar, the alias name generated would be:
The protocol and object identifier as defined in the file follow. For example:
However if the filename identifier is already part of the object name, it is not prefixed to the object name. For example, if the MIB filename were new.mib, the filename identifier in this file was new and the object name was newMibVar, the alias name generated would be as follows:
The alias name woud not be as follows:
You can also modify the mib.alias file with any text editor. This is the most convenient way to add a name definition to an already existing MIB object. For instance, if you wanted to define the name UpTimeInterval as the standard MIB object sysUptime, make the following entry in the mib.alias file:
UpTimeInterval{SNMP::_isoorg_dod_internet_mgmt_mib_system_sysUpTime }
At times, you might want to have several names for the same MIB object For instance, if you want to define the names Myhost, Ciscohost, and Routername as the Cisco Systems private MIB object CISCO-MIB-hostName, make the following entries in the mib.alias file:
Myhost{SNMP::_isoorg_dod_internet_private_enterprises_cisco_local_lsystem_hostName}
CiscoHost{SNMP::_isoorg_dod_internet_private_enterprises_cisco_local_lsystem_hostName}
Routername{SNMP::_isoorg_dod_internet_private_enterprises_cisco_local_lsystem_hostName}
At times, you might want to have a single name for the several MIB objects. For instance, if you want to define the name Routemetric to include the four objects SNMP::43.6.1.2.1.4.21.1.3, SNMP::43.6.1.2.1.4.21.1.4, SNMP::43.6.1.2.1.4.21.1.5, and SNMP::43.6.1.2.1.4.21.1.6, make the following entries in the mib.alias file:
Routemetric {
SNMP::43.6.1.2.1.4.21.1.3
SNMP::43.6.1.2.1.4.21.1.4
SNMP::43.6.1.2.1.4.21.1.5
SNMP::43.6.1.2.1.4.21.1.6
}
When you start CiscoWorks, the changes you made to the mib.alias file are used when you ask CiscoWorks to poll for that object.
There are two forms of directory pathing:
CiscoWorks requires the mib.alias file to appear in the same directory as the mib.bin file. CiscoWorks software looks for the MIB alias file in the directory $NMSROOT/etc/mibs or $NMSROOT/MIBDIR. NMSROOT defines the root directory for all Network Management System (NMS) software. MIBDIR is a relative path name that defines the directory below the NMS root directory which contains one or more MlB files and the mib.alias file.
If MIBDIR is not defined, the MIB directory defaults to $NMSROOT/etc/mibs. If a full path to the MIB directory or a MIB filename is specified using the --p or --f options, NMSROOT and MIBDIR are ignored.
The base name of the output MIB file will default to mib.bin unless a specific binary output file is defined. The directory in which the output file appears is determined as follows:
The program used to build the binary MIB file is mibbld. The program checks the contents of all the .mib files in the specified directory for syntax errors and creates a binary format mib.bin and alias.gen files usable by CiscoWorks.
The format of the statement used to invoke mibbld is:
The mibbld command options are described in Table A-2.
Table A-2 Mibbld Command Options
| Optionef | Descriptionefault *.mib) |
|---|---|
| --f MibFile | The MIB file to be processed is specified by filename MibFile (default *.mib). |
| --o OutMib | The name of the output file for the MIB binary file (default mib.bin). |
| --p PathToMibs | Process all MIB files found in the directory specified by the path name PathToMibs (default $NMSROOT/$MIBDIR). The environment objects, NMSROOT and MIBDIR, are ignored. |
| --a AliasFile | The name of output file for the aliases (default alias.gen). |
| --w WarnLevel | Set the warning message level at the level specified by WarnLevel. A level of 0 suppresses all warning messages (including "unknown variable type," which are desirable). The default setting is 1. Mibbld will issue warning and error messages regarding syntax errors, bad keywords, etc. For this reason it is wise to run with the warning level set to 1 or greater. |
| --t | Display MIB table after processing (on stdout). |
| --n | Disable alias generation. |
| --v | Display copyright and version information (on stdout). |
| --h | Display help information (on stderr). |
If you run mibbld with out specifying full path names, mibbld looks for the environment objects NMSROOT and MIBDIR.
The showmib utility is used to display the contents of the binary MIB file in a tree structure. The utility also checks the contents of the MIB alias file against the MIB tree. The form of the showmib command is:
The showmib command processes the contents of a binary format MIB file and displays the contents in a hierarchical tree structure starting from the tree's root. The MIB alias file is then processed. Aliases are displayed with corresponding fully qualified object IDs.
The showmib command options are described in Table A-3.
Table A-3 Showmib Command Options
| Showmib Option | Description |
| -a AliasFile | Name of MIB alias file. |
| -f MibFile | Processes the single MIB file specified by filename (path name) MibFile. |
| --pPathToMibs | Processes all MIB files found in the directory specified by path name PathToMibs. The Environment objects NMSROOT and MIBDIR are ignored. |
| --sSuppressO | Suppress output. If SuppressO is set to m, the output of the MIB tree is suppressed.If SuppressO is set to a, the output of the output of aliases is suppressed.If set to -h, displays the showmib options list. |
If you run showmib with no arguments, it looks for the environment objects NMSROOT and MIBDIR.
The aliaschk program ensures that alias names defined in alias.gen do not conflict with alias names in alias.master.
The last step in the makemib process is to concatenate the alias.master and alias.gen files together as mib.alias. Enter the following the following UNIX command:
hostname% cat alias.master alias.gen > mib.alias
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