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Table Of Contents
Related Features and Technologies
Supported Standards, MIBs, and RFCs
HSRP MIB
This feature module describes the addition of HSRP MIB support for Simple Network Management Protocol (SNMP) in Cisco IOS Release 12.0(12)S. It includes information on the benefits of the new feature, supported platforms, supported standards, and the modified Cisco IOS commands used to enable HSRP monitoring.
This document includes the following sections:
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Supported Standards, MIBs, and RFCs
Feature Overview
Hot Standby Router Protocol (HSRP) is a protocol developed by Cisco which provides high network availability and transparent network topology changes. Cisco IOS Release 12.0(12)S adds support for the HSRP MIB (previously supported in Cisco IOS 12.0 T releases and Cisco IOS 12.1-based releases only), which allows the monitoring and configuration of HSRP groups using Simple Network Management Protocol (SNMP).
SNMP Get operations can be used from a network management system (NMS) to get reports about HSRP groups in a network. HSRP MIB support also allows you to enable or disable the sending of SNMP notifications from the Cisco IOS command-line interface (CLI). These notifications (traps or informs) are sent to the NMS when a routing device leaves or enters the active or standby state.
Four MIB tables are supported by this feature: cHsrpGrpEntry table, defined in CISCO-HSRP-MIB.my, and cHsrpExtIfTrackedEntry, cHsrpExtSecAddrEntry, and cHsrpExtIfEntry, defined in CISCO-HSRP-EXT-MIB.my. The cHsrpGrpEntry table consists of all the group information defined in RFC 2281, Cisco Hot Standby Router Protocol; the other tables consist of the Cisco extensions to RFC 2281, which are defined in CISCO-HSRP-EXT-MIB.my
Benefits
Allows the monitoring of HSRP activity through network management applications.
Restrictions
The Cisco IOS software supports a read-only version of the MIB, and Set operations are not supported.
Related Features and Technologies
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Related Documents
For information about HSRP, see the chapter "Using HSRP for Fault-Tolerant IP Routing" in the Internetworking Case Studies document.
For information about SNMP, see the chapter "Monitoring the Router and Network" in the Configuration Fundamentals Configuration Guide, Release 12.0.
Supported Platforms
The HSRP MIB is supported on all Cisco platforms which support both HSRP and SNMP. Cisco IOS Release 12.0(12)S adds support for the HSRP MIB on the following platforms:
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Supported Standards, MIBs, and RFCs
Standards
No standards are supported for this feature.
MIBs
HSRP MIB support consists of the following MIBs and related files:
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For lists of supported MIBs by platform, and to download Cisco MIBs, go to the Cisco MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml
RFCs
RFC 2281, Cisco Hot Standby Router Protocol
Configuration Tasks
Perform the following tasks to enable HSRP trap support and verify HSRP trap operation.
Enabling HSRP Traps
HSRP MIB trap support is enabled using the hsrp option in the snmp-server enable and snmp-server host commands, as follows.
Verifying HSRP Operation
Use the following procedure to verify that the HSRP feature is enabled:
For each network that has had HSRP configured, enter the show standby command to verify the protocol is running.
Router# show standbyEthernet0 - Group 0Local state is Active, priority 100, may preemptHellotime 3 holdtime 10Next hello sent in 0:00:00Hot standby IP address is 198.92.72.29 configuredActive router is localStandby router is 198.92.72.21 expires in 0:00:07Standby virtual mac address is 0000.0c07.ac00Tracking interface states for 2 interfaces, 2 up:Up Serial0Up Serial1The local state report indicates the state of the router, and can be one of the following:
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Configuration Examples
The following examples show how to configure HSRP on two routers and enable the HSRP MIB trap support feature. As in many environments, one router is preferred as the active one. This is realized by configuring it at a higher priority level and enabling preemption. In the following example, the active router is referred to as the primary router. The second router is referred to as the backup router:
Primary Router
interface Ethernet1ip address 15.1.1.1 255.255.0.0no ip redirectsstandby priority 200 preemptstandby preemptstandby ip 15.1.1.3snmp-server enable traps hsrpsnmp-server host yourhost.cisco.com public hsrpBackup Router
interface Ethernet1ip address 15.1.1.2 255.255.0.0no ip redirectsstandby priority 101standby ip 15.1.1.3snmp-server enable traps hsrpsnmp-server host myhost.cisco.com public hsrpCommand Reference
This section documents the following modified commands for the HSRP MIB feature. All other commands used with this feature are documented in the Cisco IOS Release 12.0 command references.
snmp-server enable traps
To enable the router to send SNMP traps and informs, use the snmp-server enable traps global configuration command. To disable SNMP notifications, use the no form of this command.
snmp-server enable traps [notification-type] [notification-option]
no snmp-server enable traps [notification-type] [notification-option]
Syntax Description
Defaults
This command is disabled by default. Most notification types are disabled. However, some notification types cannot be controlled with this command. For example, some notification types are always enabled. Other notification types are enabled by a different command. For example, linkUp/linkDown notifications for specific interfaces are controlled by the snmp trap link-status command.
If you enter this command with no notification-type keywords, the default is to enable all notification types controlled by this command.
Command Modes
Global configuration
Command History
11.1
This command was introduced.
12.0(12)S
The following keywords were added for the 12.0 S train:
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Usage Guidelines
This command is useful for disabling notifications that are generating a large amount of useless noise.
SNMP notifications can be sent as traps or inform requests. This command enables both traps and inform requests for the specified notification types.
If you do not enter an snmp-server enable traps command, no notifications controlled by this command are sent. To configure the router to send these SNMP notifications, you must enter at least one snmp-server enable traps command. If you enter the command with no keywords, all notification types are enabled. If you enter the command with a keyword, only the notification type related to that keyword is enabled. To enable multiple types of notifications, you must issue a separate snmp-server enable traps command for each notification type and notification option.
The snmp-server enable traps command is used in conjunction with the snmp-server host command. Use the snmp-server host command to specify which host or hosts receive SNMP notifications. To send notifications, you must configure at least one snmp-server host command.
For a host to receive a notification controlled by this command, both the snmp-server enable traps command and the snmp-server host command for that host must be enabled. If the notification type is not controlled by this command, just the appropriate snmp-server host command must be enabled.
The notification types used in this command all have an associated MIB object that allows them to be globally enabled or disabled. Not all of the notification types available in the snmp-server host command have notificationEnable MIB objects, so some of these notifications cannot be controlled using the snmp-server enable traps command.
Examples
The following example sends HSRP MIB traps to the host specified by the name myhost.cisco.com. The community string is defined as public.
snmp-server enable traps hsrpsnmp-server host myhost.cisco.com traps version 2c public hsrpThe following example enables the router to send all traps to the host myhost.cisco.com using the community string public:
snmp-server enable trapssnmp-server host myhost.cisco.com publicThe following example enables the router to send Frame Relay and environmental monitor traps to the host myhost.cisco.com using the community string public:
snmp-server enable traps frame-relaysnmp-server enable traps envmon temperaturesnmp-server host myhost.cisco.com publicThe following example will not send traps to any host. The BGP traps are enabled for all hosts, but the only the ISDN traps enabled to be sent to a host.
snmp-server enable traps bgpsnmp-server host bob public isdnThe following example enables the router to send all inform requests to the host myhost.cisco.com using the community string public:
snmp-server enable trapssnmp-server host myhost.cisco.com informs version 2c publicRelated Commands
snmp-server host
To specify the recipient of an SNMP notification operation, use the snmp-server host global configuration command. To remove the specified host from the configuration, use the no form of this command.
snmp-server host host [traps | informs] [version {1 | 2c | 3 [auth | priv | noauth]}] community-string [udp-port port-number] [notification-type]
no snmp-server host host [traps | informs] [notification-type]
Syntax Description
Defaults
This command is disabled by default (no notifications are sent).
If you enter this command with no keywords, the default is to send all trap types to the host. No informs will be sent to this host.
If no version keyword is present, the default is version 1. If no traps or informs keyword is present, traps are enabled.
The no snmp-server host command with no keywords will disable traps, but not informs, to the host. To disable informs, use the no snmp-server host informs command.
Command Modes
Global configuration
Command History
Usage Guidelines
SNMP notifications can be sent as traps or inform requests. Traps are unreliable because the receiver does not send acknowledgments when it receives traps. The sender cannot determine if the traps were received. However, an SNMP entity that receives an inform request acknowledges the message with an SNMP response PDU. If the sender never receives the response, the inform request can be sent again. Thus, informs are more likely to reach their intended destination.
However, informs consume more resources in the agent and in the network. Unlike a trap, which is discarded as soon as it is sent, an inform request must be held in memory until a response is received or the request times out. Also, traps are sent only once, while an inform may be retried several times. The retries increase traffic and contribute to a higher overhead on the network.
If you do not enter an snmp-server host command, no notifications controlled by this command are sent. To configure the router to send those SNMP notifications, you must enter at least one snmp-server host command. If you enter the command with no keywords, all trap types are enabled for the host. To enable multiple hosts, you must issue a separate snmp-server host command for each host. You can specify multiple notification types in the command for each host.
When multiple snmp-server host commands are given for the same host and kind of notification (trap or inform), each succeeding command overwrites the previous command. Only the last snmp-server host command will be in effect. For example, if you enter an snmp-server host inform command for a host and then enter another snmp-server host inform command for the same host, the second command will replace the first.
The snmp-server host command is used in conjunction with the snmp-server enable command. Use the snmp-server enable command to specify which SNMP notifications are sent globally. For a host to receive most notifications, at least one snmp-server enable command and the snmp-server host command for that host must be enabled.
However, some notification types cannot be controlled with the snmp-server enable command. For example, some notification types are always enabled. Other notification types are enabled by a different command. For example, the linkUpDown notifications are controlled by the snmp trap link-status command. These notification types do not require an snmp-server enable command.
A notification type option's availability depends on the router type and Cisco IOS software features supported on the router. For example, the envmon notification type is available only if the environmental monitor is part of the system (for example, the Cisco 12000 series GSR platforms use the environmental monitor).
Examples
The following example sends HSRP MIB traps to the host specified by the name myhost.cisco.com. The community string is defined as public.
snmp-server enable traps hsrpsnmp-server host myhost.cisco.com traps version 2c public hsrpThe following example sends the SNMP traps defined in RFC 1157 to the host specified by the name myhost.cisco.com. The community string is defined as comaccess.
snmp-server enable trapssnmp-server host myhost.cisco.com comaccess snmpThe following example sends the SNMP and Cisco environmental monitor enterprise-specific traps to address 172.30.2.160:
snmp-server enable trapssnmp-server host 172.30.2.160 public snmp envmonThe following example enables the router to send all traps to the host myhost.cisco.com using the community string public:
snmp-server enable trapssnmp-server host myhost.cisco.com publicThe following example will not send traps to any host. The BGP traps are enabled for all hosts, but only the ISDN traps are enabled to be sent to a host.
snmp-server enable traps bgpsnmp-server host bob public isdnThe following example enables the router to send all inform requests to the host myhost.cisco.com using the community string public:
snmp-server enable trapssnmp-server host myhost.cisco.com informs version 2c publicRelated Commands
Glossary
Hot Standby Routing Protocol—See HSRP.
HSRP—Hot Standby Routing Protocol. Protocol used among a group of routers for selecting an active router and a standby router. (An active router is the router of choice for routing packets; a standby router is a router that takes over the routing duties when an active router fails, or when preset conditions are met.)
Management Information Base—See MIB.
MIB—Management Information Base. Database of network management information that is used and maintained by a network management protocol such as SNMP. The value of a MIB object can be changed or retrieved using SNMP commands, usually through a network management system. MIB objects are organized in a tree structure that includes public (standard) and private (proprietary) branches.
Simple Network Management Protocol—See SNMP.
SNMP—Simple Network Management Protocol. Management protocol used almost exclusively in TCP/IP networks. SNMP provides a means to monitor and control network devices, and to manage configurations, statistics collection, performance, and security.
trap—Message sent by an SNMP agent to a network management station, console, or terminal to indicate the occurrence of a significant event, such as a specifically defined condition or a threshold that was reached.