The Cisco Express Forwarding--SNMP CEF-MIB Support feature introduces the CISCO-CEF-MIB, which allows management applications through the use of the Simple Network Management Protocol (SNMP) to configure and monitor Cisco Express Forwarding operational data and to provide notification when Cisco Express Forwarding encounters specific configured events. This module describes how to use the CISCO-CEF-MIB to manage and monitor objects related to Cisco Express Forwarding operation.
Cisco Express Forwarding is an advanced Layer 3 IP switching technology. It optimizes network performance and scalability for all kinds of networks: those that carry small amounts of traffic and those that carry large amounts of traffic in complex patterns, such as the Internet and networks characterized by intensive web-based applications or interactive sessions.
Your software release may not support all the features documented in this module. For the latest caveats and feature information, see
Bug Search Tool and the release notes for your platform and software release. To find information about the features documented in this module, and to see a list of the releases in which each feature is supported, see the feature information table at the end of this module.
Use Cisco Feature Navigator to find information about platform support and Cisco software image support. To access Cisco Feature Navigator, go to
www.cisco.com/go/cfn. An account on Cisco.com is not required.
Prerequisites for SNMP CEF-MIB Support
Cisco Express Forwarding or distributed Cisco Express Forwarding must be configured on your system.
The Cisco Express Forwarding infrastructure introduced in Cisco IOS Release12.2(25)S must be included in the image on your system.
The router on which the Cisco Express Forwarding--SNMP CEF-MIB Support features is to be used must be configured for SNMP access. See the Configuring the Router to Use SNMP of this document for more information.
Cisco Express Forwarding is an advanced Layer 3 IP switching technology. It uses a Forwarding Information Base (FIB) to make IP destination prefix-based switching decisions. The FIB is conceptually similar to a routing table or information base. It maintains the forwarding information contained in the IP routing table. When routing or topology changes occur in the network, the IP routing table is updated, and those changes are propagated to the FIB. The FIB maintains next-hop address information based on the information in the IP routing table. The two main components of Cisco Express Forwarding operation are the FIB and adjacency tables.
Cisco Express Forwarding uses adjacency tables to prepend Layer 2 addressing information. An adjacency table maintains Layer 2 next-hop addresses for all FIB entries. Nodes in the network are said to be adjacent if they can reach each other with a single hop across a link layer. Cisco Express Forwarding discovers and solves adjacencies and populates the adjacency tables.
Note
The CISCO-CEF-MIB prefix database and its related database can be very large. Therefore, executing a command that displays the prefix table could take a considerable amount of time.
Benefits of CISCO-CEF-MIB
Command-line interface (CLI) show commands are available to obtain Cisco Express Forwarding operational information. Managing Cisco Express Forwarding using the CLI can be a time-consuming task. The increasing capacity of Cisco routers makes parsing the show commands output to obtain the needed Cisco Express Forwarding operational parameters more and more difficult.
In Cisco IOS Release 12.2(31)SB and later releases, the CISCO-CEF-MIB allows you to manage and monitor the Cisco Express Forwarding operation using SNMP. In addition, you can configure SNMP to notify you if Cisco Express Forwarding encounters errors.
The CISCO-CEF-MIB introduced with the Cisco Express Forwarding--SNMP CEF-MIB Support feature gives you real-time access to operational information stored in the FIB and adjacency tables, switching statistics, and information on resource failures. The feature enables you to configure parameters related to Cisco Express Forwarding features by utilizing a MIB implementation based on SNMP. This information is accessed using get and set commands entered on the network management system (NMS) workstation or host system for which SNMP has been implemented. The NMS workstation is also known as the SNMP manager.
Cisco Express Forwarding is available in all Cisco routers. However, CISCO-CEF-MIB support of Cisco Express Forwarding management is dependent on the infrastructure introduced in Cisco IOS Release 12.2(22)S.
The implementation of the CISCO-CEF-MIB in Cisco IOS Release 12.2(31)SB2, Cisco IOS Release 12.2(33)SRC,and Cisco IOS Release 12.2(33)SB manages Cisco Express Forwarding instances running on the Route Processor (RP). Information about Cisco Express Forwarding running on the line cards is available to the RP in reference to Cisco Express Forwarding peers only.
The CISCO-CEF-MIB supports configuration and monitoring for both IP versions, IP Version 4 (IPv4) and IP Version 6 (IPv6).
Information Managed by the CISCO-CEF-MIB
SNMP has historically been used to collect network information. SNMP permits retrieval of critical information from network elements such as routers, switches, and workstations.
The CISCO-CEF-MIB provides managed objects that enable a network administrator to monitor the following:
Cisco Express Forwarding administrative and operational states as displayed in the output of the showipcefsummary command
Notifications for Cisco Express Forwarding events: Cisco Express Forwarding state changes, Cisco Express Forwarding failures (with a predefined reason), and Route Processor (RP) and line card inconsistencies
Parameters related to Cisco Express Forwarding for the associated interface as displayed by the showcefinterface command
Line card Cisco Express Forwarding states and line card Cisco Express Forwarding FIB states in the Linecard table as displayed by the showceflinecardcommand
Cisco Express Forwarding statistics: switching statistics, punt counters and punt-to-host counters as displayed by the showipcefswitchingstatscommand, and per-prefix counters and nonrecursive counters
IPv4 and IPv6 notification, when Cisco Express Forwarding is switched between disable and enable and between Cisco Express Forwarding and distributed Cisco Express Forwarding
The SNMP CISCO-CEF-MIB provides managed objects that enable a network administrator to configure the following:
Cisco Express Forwarding and distributed Cisco Express Forwarding administration status
The SNMP CISCO-CEF-MIB allows the configuration and management of objects related to Cisco Express Forwarding. The MIB contains the following object groups:
CEF FIB group
CEF Adjacency group
CEF Forwarding Element group
CEF Cfg group
CEF Interface group
CEF Peer group
CEF Consistency (CC) group
CEF State Group
CEF Notification Control group
In the CISCO-CEF-MIB, configuration objects are defined as read-write, and the other objects are defined as read only.
The CISCO-CEF-MIB contains tables related to the Cisco Express Forwarding object groups. These tables provide information about prefixes, forwarding paths, adjacencies, output chain elements (OCEs), prefix-based statistics, information about Cisco Express Forwarding configuration, consistency checkers, switching statistics, and managed objects specific to line card-specific.
The CISCO-CEF-MIB also defines Cisco Express Forwarding notifications that you can enable or disable through the MIB or CLI commands.
The index for most tables in the CISCO-CEF-MIB is entPhysicalIndex.
CISCO-CEF-MIB Tables
The CEF FIB Summary table (cefFIBSummaryTable) contains the number of forwarding prefixes for both IPv4 and IPv6 protocols. It is a summary of the CEF Forwarding table.
The CEF Forwarding table (cefPrefixTable) lists all the prefixes and related counters. It also contains a pointer to the CEF Forwarding Element Selection table.
The CEF Longest Match Prefix table (cefLMPrefixTable) returns the longest prefix match for the given destination address. An optional cefLMPrefixSpinLock object is provided to reduce conflict in instances when more than one application acts on the CEF Longest Match Prefix table.
The CEF Path table (cefPathTable) lists all the Cisco Express Forwarding paths.
The CEF Adjacency Summary table (cefAdJSummaryTable) contains the total number of complete, incomplete, fixup, and redirect adjacencies for all link types.
The CEF Adjacency table (cefAdjTable) lists all the adjacencies. It contains the adjacency source, encapsulation string, fixup, and Layer 3 maximum transmission unit (MTU) associated with the adjacency entry. It contains a pointer to the forwarding element selection table (if the adjacency is a MID chain adjacency).
The CEF Forwarding Element Selection table (cefFESelectionTable) represents the OCE chains in flattened format. This table shows only the labels, table ID, and adjacency traversed in the OCE chain. It also contains the weight associated with each OCE chain.
CEF Cfg table (cefCfgTable) contains all the global configuration parameters related to Cisco Express Forwarding: administration and operational status, accounting-related configuration parameters, load-sharing algorithms and IDs, and traffic statistics parameters.
CEF Resource table (cefResourceTable) contains information about resources for Cisco Express Forwarding: the memory status of the process memory pool and reasons for the Cisco Express Forwarding resource failure notifications.
CEF Interface table (cefIntTable) contains the interface-specific Cisco Express Forwarding parameters: interface switching state, interface load sharing (per packet and per destination), and interface nonrecursive routing (internal and external).
CEF Peer table or Linecard table (cefPeerTable) contains Cisco Express Forwarding information related to peers on a managed line card: line card operational state and the number of times the line card session resets.
CEF Peer FIB table (cefPeerFIBTable) contains information about the operational state of the Forwarding Information Bases (FIBs) on each line card.
CEF Switching Statistics table (cefSwitchingStatsTable) contains the switching statistics for each switching path: drop counters, punt counters, and punt-to-host counters.
CEF IP Prefix Consistency Checker Global group (cefCCGlobalTable) contains all global configuration parameters for the consistency checkers: auto repair, enable and disable, delay, and hold down; enable or disable the passive consistency checkers; enable or disable the error messages for consistency detection; and the mechanism to activate the full scan consistency checkers. This table also displays the state of full scan consistency checkers.
CEF Consistency Checker Type table (cefCCTypeTable) contains the consistency checker type specific parameters: frequency and count of scan for passive scanners and the queries sent, ignored, checked, and iterated.
CEF Inconsistency Record table (cefInconsistencyRecordTable) contains the detected inconsistency records: prefix address and length, table ID, consistency checker type, slot ID, and the reason for the inconsistency (missing or checksum error).
The figure below shows the contents of the CISCO-CEF-MIB main tables and the relationships of the tables to one another.
Figure 1
CISCO-CEF-MIB Main Tables, Table Contents, and Relationships
Operations Available Through the CISCO-CEF-MIB
You can use SNMP
getandsetcommands to configure and monitor Cisco Express Forwarding operations that are available through the CISCO-CEF-MIB tables. This section describes the configuration and monitoring operations for each table.
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF FIB Summary table (cefFIBSummaryTable).
Gets the number of forwarding prefixes for IPv4 and IPv6
cefFIBSummaryFwdPrefixes
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Forwarding table (cefPrefixTable).
Table 2
CEF Forwarding Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets the forwarding information for the entry
cefPrefixForwardingInfo
Gets the number of packets forwarded by the prefix
cefPrefixPkts
Gets the number of packets forwarded by the prefix in a 64-bit value
cefPrefixHCPkts
Gets the number of bytes forwarded by the prefix
cefPrefixBytes
Gets the number of bytes forwarded by the prefix in a 64-bit value
cefPrefixHCBytes
Gets the number of internal nonrecursive packets forwarded by the prefix
cefPrefixInternalNRPkts
Gets the number of internal nonrecursive packets forwarded by the prefix in a 64-bit value
cefPrefixInternalNRHCPkts
Gets the number of internal nonrecursive bytes forwarded by the prefix
cefPrefixInternalNRBytes
Gets the number of internal nonrecursive bytes forwarded by the prefix in a 64-bit value
cefPrefixInternalNRHCBytes
Gets the number of external nonrecursive packets forwarded by the prefix
cefPrefixExternalNRPkts
Gets the number of external nonrecursive packets forwarded by the prefix in a 64-bit value
cefPrefixExternalNRHCPkts
Gets the number of external nonrecursive bytes forwarded by the prefix
cefPrefixExternalNRBytes
Gets the number of external nonrecursive bytes forwarded by the prefix in 64-bit value
cefPrefixExternalNRHCBytes
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Longest Match Prefix table (cefLMPrefixTable).
Table 3
CEF Longest Match Prefix Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets or sets the lock for creation or modification of the longest match prefix entries
cefLMPrefixSpinLock
Gets the state of the destination prefix request
cefLMPrefixState
Gets the network prefix address for the destination prefix request
cefLMPrefixAddr
Gets the network prefix length for the destination prefix request (the same display as the
showipcefexact-route command)
cefLMPrefixLen
Gets the status of a table entry
cefLMPrefixRowStatus
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Path table (cefPathTable).
Table 4
CEF Path Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets the type of Cisco Express Forwarding path for a prefix
cefPathType
Gets the interface associated with this Cisco Express Forwarding path
cefPathInterface
Gets the next-hop address for the Cisco Express Forwarding path
cefPathNextHopAddr
Gets the recursive Virtual Private Network (VPN) routing and forwarding (VRF) instance name associated with this path
cefPathRecurseVrfName
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Adjacency Summary table (cefAdjSummaryTable).
Gets the number of adjacencies for Layer 2 encapsulation
cefAdjSummaryFixup
Gets the number of adjacencies for IP redirect
cefAdjSummaryRedirect
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Adjacency table (cefAdjTable).
Table 6
CEF Adjacency Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets the adjacency source
cefAdjSource
Gets the adjacency Layer 2 encapsulation
cefAdjEncap
Gets the adjacency fixup
cefAdjFixup
Gets the Layer 3 maximum transmission unit (MTU) for the adjacency
cefAdjMTU
Gets the forwarding information in cefFESelectionTable
cefAdjForwardingInfo
Gets the number of packets transmitted
cefAdjPkts
Gets the number of packets transmitted in a 64-bit version
cefAdjHCPkts
Gets the number of bytes transmitted
cefAdjBytes
Gets the number of bytes transmitted in a 64-bit version
cefAdjHCBytes
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Forwarding Element Selection table (cefFESelectionTable).
Table 7
CEF Forwarding Element Selection Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets any special processing for a forwarding element
cefFESelectionSpecial
Gets the Multiprotocol Label Switching (MPLS) labels for a forwarding element
cefFESelectionLabels
Gets the adjancency type for a forwarding element
cefFESelectionAdjLinkType
Gets the interface for the adjacency for a forwarding element
cefFESelectionAdjInterface
Gets the next-hop address type for the adjacency for a forwarding element
cefFESelectionAdjNextHopAddrType
Gets the next-hop address for the adjacency for a forwarding element
cefFESelectionAdjNextHopAddr
Gets the connection ID for the adjacency for a forwarding element
cefFESelectionAdjConnId
Gets the VRF name for the lookup for a forwarding element
cefFESelectionVrfName
Gets the weighting for load balancing for a forwarding element
cefFESelectionWeight
The table below lists the Cisco Express Forwarding configuration and monitoring operations and associated MIB objects provided by the CEF Cfg table (cefCfgTable).
Table 8
CEF Cfg Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Enables or disables a Cisco Express Forwarding instance
cefCfgAdminState
Queries a Cisco Express Forwarding operational instance
cefCfgOperState
Enables or disables a distributed Cisco Express Forwarding instance
cefCfgDistributionAdminState
Queries a distributed Cisco Express Forwarding operational instance
cefCfgDistributionOperState
Gets or sets Cisco Express Forwarding network accounting options
cefCfgAccountingMap
nonRecursive (0)
perPrefix (1)
prefixLength (2)
Gets or sets Cisco Express Forwarding load sharing algorithm options
cefCfgLoadSharingAlgorithm
none (1) - Load sharing is disabled.
original (2)
tunnel (3)
universal (4)
Gets or sets a load sharing ID
cefCfgLoadSharingID
Gets or sets a traffic interval timer for Cisco Express Forwarding traffic statistics
cefCfgTrafficStatsLoadInterval
Gets or sets a frequency timer for the line card to send traffic statistics to the RP
cefCfgTrafficStatsUpdateRate
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Resource table (cefResourceTable).
Table 9
CEF Resource Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Object
Gets the memory status of process memory pool for Cisco Express Forwarding
cefResourceMemoryUsed
Gets the reason for the Cisco Express Forwarding resource failure notification
cefResourceFailureReason
The table below lists the Cisco Express Forwarding configuration and monitoring operations and associated MIB objects provided by the CEF Interface table (cefIntTable).
Table 10
CEF Interface Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Gets or sets the Cisco Express Forwarding switching state of the interface
cefIntSwitchingState
cefEnabled (1)
distCefEnabled (2)
cefDisabled (3)
Gets or sets the type of Cisco Express Forwarding Load sharing on the interface
cefIntLoadSharing
perPacket (1)
perDestination (2)
Gets or sets Cisco Express Forwarding nonrecursive accounting on the interface
cefIntNonrecursiveAccouting
internal (1)
external (2)
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Peer table (or Linecard table) (cefPeerTable).
Table 11
CEF Peer Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Gets the Cisco Express Forwarding operational instance of the peer entity
cefPeerOperState
Gets how many times the session with the Peer resets
cefPeerNumberOfResets
The table below lists the Cisco Express Forwarding monitoring operation and associated MIB object provided by the CEF Peer FIB table (cefPeerFIBTable).
Gets the current Cisco Express Forwarding FIB operation state of the peer entity
cefPeerFIBOperState
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Prefix Length Statistics table (cefStatsPrefixTable).
Gets the number of queries (lookups) in the FIB database for a prefix length
cefStatsPrefixQueries
Gets the number of queries (lookups) in the FIB database for a prefix length in a 64-bit value
cefStatsPrefixHCQueries
Gets the number of inserts in the FIB database for a prefix length
cefStatsPrefixInserts
Gets the number of inserts in the FIB database for a prefix length in a 64-bit value
cefStatsPrefixHCInsert
Gets the number of deletes in the FIB database for a prefix length
cefStatsPrefixDeletes
Gets the number of deletes in the FIB database for a prefix length in a 64-bit version
cefStatsPrefixHCDeletes
Gets the number of elements in the FIB database for a prefix length
cefStatsPrefixElements
Gets the number of elements in the FIB database for a prefix length in a 64-bit value
cefStatsPrefixHCElements
The table below lists the Cisco Express Forwarding monitoring operations and associated MIB objects provided by the CEF Switching Statistics table (cefSwitchingStatsTable).
Gets the switching path of a Cisco Express Forwarding instance
cefSwitchingPath
Gets the number of packets dropped by a Cisco Express Forwarding instance
cefSwitchingDrop
Gets the number of packets dropped by a Cisco Express Forwarding instance in a 64-bit value
cefSwitchingHCDrop
Gets the number of packets that could be punted
cefSwitchingPunt
Gets the number of packets that could be punted in a 64-bit value
cefSwitchingHCPunt
Gets the number of packets that are punted to the host
cefSwitchingPunt2Host
Gets the number of packets that are punted to the host in a 64-bit value
cefSwitchingHCPunt2Host
The table below lists the Cisco Express Forwarding configuration and monitoring operations and associated MIB objects provided by the CEF IP Prefix Consistency Global Checker group (cefCCGlobalTable).
Table 15
CEF IP Prefix Consistency Global Checker Group--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Enables or disables auto repairing of the consistency checkers
cefCCGlobalAutoRepairEnabled
Gets or sets the consistency checker wait time before fixing the inconsistency
cefCCGlobalAutoRepairDelay
Gets or sets the consistency checker wait time to reenable auto repair after auto repair runs
cefCCGlobalAutoRepairHoldDown
Enables or disables error message generation for an inconsistency
cefCCGlobalErrorMsgEnabled
The table below lists the Cisco Express Forwarding configuration and monitoring operations and associated MIB objects provided by the CEF Consistency Checker Type table (cefCCTypeTable).
Table 16
CEF Consistency Checker Type Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Enables or disables the passive consistency checker
cefCCEnabled
Gets or sets the maximum number of prefixes per scan
cefCCCount
Gets or sets the period between scans for the consistency checker
cefCCPeriod
Gets the number of prefix consistency queries sent to the Cisco Express Forwarding FIB
cefCCQueriesSent
Gets the number of prefix consistency queries ignored by the consistent checker
cefCCQueriesIgnored
Gets the number of prefix consistent queries iterated back to the database
cefCCQueriesIterated
Gets the number of prefix consistent queries processed
cefCCQueriesChecked
The table below lists the Cisco Express Forwarding configuration and monitoring operations and associated MIB objects provided by the CEF Inconsistency Record table (cefInconsistencyRecordTable).
Table 17
CEF Inconsistency Record Table--Cisco Express Forwarding Operations and Associated MIB Objects
Cisco Express Forwarding Operation
MIB Objects
Gets the network prefix type for the inconsistency
cefInconsistencyPrefixType
Gets the network prefix address for the inconsistency
cefInconsistencyPrefixAddr
Gets the network prefix length for the inconsistency
cefInconsistencyPrefixLen
Gets the VRF name for the inconsistency
cefInconsistencyVrfName
Gets the consistency checker type that found the inconsistency
cefInconsistencyCCType
Gets the entity in which this inconsistency occurred
cefInconsistencyEntity
Gets the reason for generating the inconsistency
cefInconsistencyReason
missing (1)
checksumErr (2)
unknown (3)
Global Objects for Cisco Express Forwarding Inconsistency
Gets the value of the system uptime at the time an inconsistency was detected
entLastInconsistencyDetectTime
Sets an object to restart all active consistency checkers
cefInconsistencyReset
Gets the status of the inconsistency reset request
cefInconsistencyResetStatus
CISCO-CEF-MIB Notifications
The table below lists the Cisco Express Forwarding operations associated with the CISCO-CEF-MIB objects that enable the sending of Cisco Express Forwarding notifications.
Table 18
Cisco Express Forwarding Notifications--Cisco Express Forwarding Operations and CISCO-CEF-MIB Objects That Enable Them
Cisco Express Forwarding Operation
MIB Object
Enables the sending of a notification on the detection of a Cisco Express Forwarding resource failure
cefResourceFailureNotifEnable
Enables the sending of a notification on the detection of a Cisco Express Forwarding peer state change
cefPeerStateChangeNotifEnable
Enables the sending of a notification on the detection of a Cisco Express Forwarding FIB peer state change
cefPeerFIBStateChangeNotifEnable
Sets the period of time after the sending of each notification event
cefNotifThrottlingInterval
Enables the sending of a notification on the detection of an inconsistency
cefInconcsistencyNotifEnable
You can enable or disable these notifications through the MIB or by entering a CLI command. The table below contains a description of the notifications and the commands you use to enable each notification.
Note
You must enter a
snmp-serverhost command before you enter a command to enable or disable a CISCO-CEF-MIB notification.
Table 19
Description of Notifications and Enabling Commands for the CEF-PROVISION-MIB Notifications
Sets up the community access string to permit access to SNMP.
The string argument is a community string that consists of from 1 to 32 alphanumeric characters and functions much like a password, permitting access to the SNMP protocol. Blank spaces are not permitted in the community string.
The viewview-name keyword-argument pair is the name of a previously defined view. The view defines the objects available to the SNMP community.
The ro keyword specifies read-only access. Authorized management stations can only retrieve MIB objects.
The rw keyword specifies read-write access. Authorized management stations can retrieve and modify MIB objects.
The ipv6naclkeywords specify the IPv6 named access list.
The access-list-number argument is an integer from 1 to 99. It specifies a standard access list of IP addresses or a string (not to exceed 64 characters) that is the name of a standard access list of IP addresses that are allowed access to the SNMP agent.
Alternatively, an integer from 1300 to 1999 that specifies a list of IP addresses in the expanded range of standard access list numbers. Devices at these addresses are allowed to use the community string to gain access to the SNMP agent.
Note
The stringargument (Step 3) andstring2argument (Step 4) provide a minimal level of security. It is advisable to provide the string for read-only access to others who need only to view and not to modify the MIB objects, and reserve the read-write access string for administrators only. The string2 argument (Step 4) should be different from the read-only string argument specified in this step.
Step 4
snmp-servercommunitystring2rw
Example:
Router(config)# snmp-server community private rw
Sets up the community access string to permit access to SNMP.
The string2 argument is a community string that consists of from 1 to 32 alphanumeric characters and functions much like a password, permitting access to the SNMP protocol. Blank spaces are not permitted in the community string.
The rw keyword specifies read-write access. Authorized management stations can retrieve and modify MIB objects.
This example allows MIB objects to be retrieved and set because a string is specified with read-write access.
Note
The stringargument (Step 3) andstring2argument (Step 4) provide a minimal level of security. It is advisable to provide the string for read-only access to others who need only to view and not to modify the MIB objects, and reserve the read-write access string for administrators only. The string2 argument (Step 4) should be different from the read-only string argument specified in the preceding step (Step 3).
Step 5
end
Example:
Router(config)# end
Exits to privileged EXEC mode.
Configuring a Host to Receive Notifications
Perform the following task to configure an SNMP host to receive CISCO-CEF-MIB notifications. Notifications provide information to assist you in the monitoring and managing of Cisco Express Forwarding operations.
Sets up the community access string to permit access to SNMP.
The string argument is a community string that consists of from 1 to 32 alphanumeric characters and functions much like a password, permitting access to the SNMP protocol. Blank spaces are not permitted in the community string.
The ro keyword specifies read-only access. Authorized management stations can only retrieve MIB objects.
The rw keyword specifies read-write access. Authorized management stations can retrieve and modify MIB objects.
Step 4
snmp-servercommunitystring2rw
Example:
Router(config)# snmp-server community private rw
Sets up the community access string to permit access to SNMP.
The string2 argument is a community string that consists of from 1 to 32 alphanumeric characters and functions much like a password, permitting access to the SNMP protocol. Blank spaces are not permitted in the community string.
The rw keyword specifies read-write access. Authorized management stations can retrieve and modify MIB objects.
This example allows MIB objects to be retrieved and set because a string is specified with read-write access.
Note
The stringargument (Step 3) andstring2argument (Step 4) provide a minimal level of security. It is advisable to provide the string for read-only access to others who need only to view and not to modify the MIB objects, and retain the read-write access string for administrators only. The string2 argument (Step 4) should be different from the read-only string argument specified in the preceding step (Step 3).
noauth--Specifies that the noAuthNoPriv security level applies to this host. This is the default security level for SNMPv3.
priv--Enables Data Encryption Standard (DES) packet encryption (also called "privacy").
The community-string argument specifies that a password-like community string be sent with the notification operation.
The udp-portport keyword and argument specify that SNMP notifications or informs are to be sent to the User Datagram Protocol (UDP) port number of the NMS host. The default is 162.
The cef keyword specifies that the Cisco Express Forwarding notification type is to be sent to the host. If no type is specified, all available notifications are sent.
Step 6
end
Example:
Router(config)# end
Exits to privileged EXEC mode.
Configuring SNMP Notifications with the CLI
Perform the following task to configure SNMP notifications for Cisco Express Forwarding events. To configure this feature using SNMP commands instead of the CLI, see the Configuring SNMP Notifications with SNMP Commands.
Enables Cisco Express Forwarding support of SNMP notifications on an NMS.
The peer-statechange keyword enables the sending of CISCO-CEF-MIB SNMP notifications for changes in the operational state of Cisco Express Forwarding peers.
The resource-failure keyword enables the sending of CISCO-CEF-MIB SNMP notifications for resource failures that affect Cisco Express Forwarding operations.
The inconsistencykeyword enables the sending of CISCO-CEF-MIB SNMP notifications for inconsistencies that occur when routing information is updated from the Routing Information Base (RIB) to the CISCO-CEF-MIB on the RP and to the CISCO-CEF-MIB on the line cards.
The peer-fib-state-change keyword enables the sending of CISCO-CEF-MIB SNMP notifications for changes in the operational state of the Cisco Express Forwarding peer FIB.
noauth--Specifies that the noAuthNoPriv security level applies to this host. This is the default security level for SNMPv3.
priv--Enables Data Encryption Standard (DES) packet encryption (also called "privacy").
The community-string argument specifies that a password-like community string be sent with the notification operation.
The cef keyword specifies that the Cisco Express Forwarding notification type is to be sent to the host. If no type is specified, all available notifications are sent.
Step 5
end
Example:
Router(config)# end
Exits to privileged EXEC mode.
Configuring SNMP Notifications with SNMP Commands
Perform the following task to configure SNMP notifications for Cisco Express Forwarding events. To configure this feature using the CLI instead of SNMP commands, see the Configuring SNMP Notifications with the CLI.
workstation% setany -v2c 10.56.125.47 public cefInconsistencyNotifEnable.0 -i 1
Enables the sending of CISCO-CEF-MIB SNMP notifications for inconsistencies that occur when routing information is updated from the RIB to the Cisco Express Forwarding FIB on the RP and to the Cisco Express Forwarding FIB on the line cards.
See Step 1 for a description of the command arguments and keywords.
Configuring the Throttling Interval with the CLI
Perform the following task to configure the throttling interval for CISCO-CEF-MIB inconsistency notifications. To configure this feature using SNMP commands instead of the CLI, see the Configuring the Throttling Interval with SNMP Commands section.
Configuring a throttling interval allows some time before an inconsistency notification is sent during the process of updating forwarding information from the Routing Information Base (RIB) to the RP and to the line card databases. As these databases are updated, inconsistencies might occur as a result of the asynchronous nature of the distribution mechanism for these databases. The throttling interval allows fleeting inconsistencies to resolve themselves before an inconsistency notification is sent.
Sets the throttling interval for the CISCO-CEF-MIB inconsistency notifications.
The
seconds argument is the time to allow before an inconsistency notification is sent during the process of updating forwarding information from the RIB to the RP and to the line card databases. A valid value is from 0 to 3600 seconds. A value of 0 disables throttle control.
Step 5
end
Example:
Router(config)# end
Exits to privileged EXEC mode.
Configuring the Throttling Interval using SNMP Commands
Perform the following task to configure the throttling interval for CISCO-CEF-MIB inconsistency notifications. To configure this feature using the CLI instead of SNMP commands, see the Configuring the Throttling Interval with the CLI.
Configuring a throttling interval allows some time before an inconsistency notification is sent during the process of updating forwarding information from the Routing Information Base (RIB) to the RP and to the line card databases. As these databases are updated, inconsistencies might occur as a result of the asynchronous nature of the distribution mechanism for these databases. The throttling interval allows fleeting inconsistencies to resolve themselves before an inconsistency notification is sent.
workstation% setany -v2c 10.56.125.47 public cefNotifThrottlingInterval.0 -1 3600
Sets the throttling interval for the CISCO-CEF-MIB inconsistency notifications.
The version argument specifies the version of SNMP that is used. Options are
-v1--SNMPv1
-v2c--SNMPv2C
-v3--SNMPv3
The ip-address argument is the IP address or IPv6 address of the SNMP notification host.
The SNMP notification host is typically a network management station (NMS or SNMP manager). This host is the recipient of the SNMP traps or informs.
Thecommunity-string argument specifies that a password-like community string be sent with the notification operation.
The -ikeywords indicate that the variable that follows is an integer.
The seconds argument is the time to allow before an inconsistency notification is sent during the process of updating forwarding information from the RIB to the RP and to the line card databases. A valid value is from 0 to 3600 seconds. A value of 0 disables throttle control.
Example Configuring a Host to Receive Notifications
The following example shows how to configure an SNMP host to receive CISCO-CEF-MIB notifications:
configure terminal
!
snmp-server community public ro
snmp-server community private rw
snmp-server host 10.56.125.47 informs version 2vc public cef
end
This example sets up SNMP host 10.56.125.47 to receive CISCO-CEF-MIB notifications as informs.
Example Configuring SNMP Notifications
This section contains examples for configuring SNMP notifications for Cisco Express Forwarding events using the CLI and using SNMP commands.
Configuring SNMP Notifications for Cisco Express Forwarding Events Using the CLI
This example shows how to use the CLI to configure CISCO-CEF-MIB SNMP notifications to be sent to host 10.56.125.47 as informs for changes in Cisco Express Forwarding peer states and peer FIB states, for Cisco Express Forwarding resource failures, and for inconsistencies in Cisco Express Forwarding events:
configure terminal
!
snmp-server community public ro
snmp-server host 10.56.125.47 informs version 2c public cef
Configuring SNMP Notifications for Cisco Express Forwarding Events Using SNMP Commands
This example shows the use of SNMP command to configure CISCO-CEF-MIB SNMP notifications to be sent to host 10.56.125.47 for changes in Cisco Express Forwarding peer states and peer FIB states, for Cisco Express Forwarding resource failures, and for inconsistencies in Cisco Express Forwarding events:
setany -v2c 10.56.125.47 public cefPeerStateChangeNotifEnable.0 -i 1
setany -v2c 10.56.125.47 public cefPeerFIBStateChangeNotifEnable.0 -i 1
setany -v2c 10.56.125.47 public cefResourceFailureNotifEnable.0 -i 1
setany -v2c 10.56.125.47 public cefInconsistencyNotifEnabled.0 -i 1
Example Configuring the Throttling Interval
This example shows the configuration of a throttling interval for the sending of Cisco Express Forwarding inconsistency notifications to the SNMP host using CLI commands and SNMP commands. The throttling interval is the amount of time that passes between the time that the inconsistency occurs and the sending of the notification to the SNMP host.
Configuring the Throttling Interval for CISCO-CEF-MIB Inconsistency Notifications Using CLI Commands
This example shows the addition of a throttling interval of 1000 seconds for the sending of Cisco Express Forwarding inconsistency notifications to the SNMP host using CLI commands:
configure terminal
!
snmp-server community public ro
snmp-server host 10.56.125.47 informs version 2c public cef
Configuring the Throttling Interval for CISCO-CEF-MIB Inconsistency Notifications Using SNMP Commands
This example shows the addition of a throttling interval of 1000 seconds for the sending of Cisco Express Forwarding inconsistency notifications to the SNMP host using an SNMP command:
setany -v2c 10.56.125.47 public cefNotifThrottlingInterval.0 -1 1000
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Table 20
Feature Information for Cisco Express Forwarding--SNMP CEF-MIB Support
The Cisco Express Forwarding--SNMP CEF-MIB Support feature introduces the CISCO-CEF-MIB that allows management applications through the use of the Simple Network Management Protocol (SNMP) to configure and monitor Cisco Express Forwarding operational data and to provide notification when Cisco Express Forwarding encounters specific configured events. This module describes how to use the CISCO-CEF-MIB to manage and monitor objects related to Cisco Express Forwarding operation.
The following commands were introduced or modified:
snmpmibcefthrottling-interval,
snmp-serverenabletrapscef,
snmp-serverhost.
Glossary
inform--A type of notification message that is more reliable than a conventional trap notification message because the informs message notification requires acknowledgment, but a trap notification does not.
IPC--Inter-Process Communication. The protocol used by routers that support distributed packet forwarding. The Cisco IOS version of IPC provides a reliable ordered delivery of messages using an underlying platform driver transport or User Date Protocol (UDP) transport protocol. Cisco IOS software IPC services allow line cards (LCs) and the central route processor (RP) in a distributed system, such as a Cisco 7500 series router, to communicate with each other by exchanging messages from the RP to the LCs. Communication messages are also exchanged between active and standby RPs. The IPC messages include configuration commands, responses to the configuration commands, and other events that are reported by an LC to the RP.
MIB--Management Information Base. A database of network management information that is used and maintained by a network management protocol such as Simple Network Management Protocol (SNMP). The value of a MIB object can be changed or retrieved by the use of SNMP commands, usually through a network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
NMS--network management station. A powerful, well-equipped computer (typically an engineering workstation) that is used by a network administrator to communicate with other devices in the network. An NMS is typically used to manage network resources, gather statistics, and perform a variety of network administration and configuration tasks. In the context of SNMP, an NMS is a device that performs SNMP queries to the SNMP agent of a managed device to retrieve or modify information.
notification--A message sent by a Simple Network Management Protocol (SNMP) agent to a network management station, console, or terminal to indicate that a significant network event has occurred.
SNMP--Simple Network Management Protocol. A network management protocol used almost exclusively in TCP/IP networks. SNMP enables a user to monitor and control network devices, manage configurations, collect statistics, monitor performance, and ensure network security.
SNMPcommunity--An authentication scheme that enables an intelligent network device to validate SNMP requests.
SNMPv2c--Version 2c of the Simple Network Management Protocol. SNMPv2c supports centralized as well as distributed network management strategies and includes improvements in the Structure of Management Information (SMI), protocol operations, management architecture, and security.
SNMPv3--Version 3 of the Simple Network Management Protocol. Interoperable standards-based protocol for network management. SNMPv3 provides secure access to devices by a combination of authenticating and encrypting packets over the network.
trap--A message sent by an SNMP agent to a network management station, console, or terminal to indicate that a significant network event has occurred. Traps are less reliable than inform requests, because the receiver of the trap does not send an acknowledgment of receipt; furthermore, the sender of the trap cannot determine if the trap was received.
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