HSRP MIB

Feature Overview

With Cisco IOS Release 12.0(3)T, the software supports the Hot Standby Routing Protocol (HSRP) Management Information Base (MIB) feature. HSRB MIB supports Simple Network Management Protocol (SNMP) get operations, to allow network devices to get reports about HSRP groups in a network from the network management station. Configuration is done from the command-line interface (CLI), and the MIB is used for getting the reports. A trap notifies the network management station when a router leaves or enters the active or standby state. When an entry is configured from the CLI, the RowStatus for that group in the MIB immediately goes to the active state.

Benefits

This feature adds MIB support for HSRP.

Restrictions

The Cisco IOS software supports a read-only version of the MIB, and set operations are not supported.

Supported Platforms

The HSRP MIB is available in all system images, and runs on all Cisco device platforms where HSRP is available.

Supported MIBs and RFC

MIBs

Four MIB tables are supported by this feature:

• cHsrpGrpEntry table defined in CISCO-HSRP-MIB.my

• cHsrpExtIfTrackedEntry, cHsrpExtSecAddrEntry, and cHsrpExtIfEntry defined in CISCO-HSRP-EXT-MIB.my

For descriptions of supported MIBs and how to use MIBs, see Cisco's MIB web site on CCO at http://www.cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml.

RFCs

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.

List of Terms and Acronyms

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.

Configuration Tasks

Perform the following tasks to enable HSRP trap support and verify HSRP trap operation.

• Enabling HSRP Traps

• Verifying HSRP Operation

Enabling HSRP Traps

The HSRP MIB trap feature runs on all Cisco device platforms where HSRP is available and running. For more information about HSRP and how to configure it on a Cisco router, see the chapter "Using HSRP for Fault-Tolerant IP Routing" in the book Cisco CCIE Fundamentals: Case Studies. See the section "Configuration Examples" later in this document for an example of how to configure HSRP and HSRP MIB trap support in your network.

HSRP MIB trap support is enabled using the hsrp option in the snmp-server enable and snmp-server host commands, as follows.

Step	Command	Purpose
1	Router(config)# snmp-server enable traps hsrp	Enables the router to send SNMP traps and informs, and HSRP notifications.
2	Router(config)# snmp-server host host community-string hsrp	Specifies the recipient of an SNMP notification operation, and that HSRP notifications be sent to the host.

Verifying HSRP Operation

Follow this 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 standby
 
Ethernet0 - Group 0
  Local state is Active, priority 100, may preempt
  Hellotime 3 holdtime 10
  Next hello sent in 0:00:00
  Hot standby IP address is 198.92.72.29 configured
  Active router is local
Standby router is 198.92.72.21 expires in 0:00:07
Standby virtual mac address is 0000.0c07.ac00
Tracking interface states for 2 interfaces, 2 up:
UpSerial0
UpSerial1
 

The local state report indicates the state of the router, and can be one of the following:

• Active---Current Hot Standby router.

• Standby---Router next in line to be the Hot Standby router.

• Speak---Router is sending packets to claim the active or standby role.

• Listen---Router is neither active nor standby, but if no messages- are received from the active or standby router, it will start to speak.

• Learn---Router is neither active nor standby, nor does it have enough information to attempt to claim the active or standby roles.

• Init---Router is not yet ready to participate in HSRP, possibly because the associated interface is not up.

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 Ethernet1
 ip address 15.1.1.1 255.255.0.0
 no ip redirects
 standby priority 200 preempt
 standby preempt
 standby ip 15.1.1.3
snmp-server enable traps hsrp
snmp-server host yourhost.cisco.com public hsrp
 

Backup Router

 interface Ethernet1
 ip address 15.1.1.2 255.255.0.0
 no ip redirects
 standby priority 101
 standby ip 15.1.1.3
snmp-server enable traps hsrp
snmp-server host myhost.cisco.com public hsrp

Command 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.

• show standby

• snmp-server enable traps

• snmp-server host

show standby

To display Hot Standby Router Protocol (HSRP) information, use the show standby EXEC command.

Syntax Description

Command Mode

EXEC

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

If you want to specify a group, you must also specify an interface type and number.

Sample Displays

The following is sample output from the show standby command:

Router# show standby
 
Ethernet0 - Group 0
  Local state is Active, priority 100, may preempt
  Hellotime 3 holdtime 10
  Next hello sent in 0:00:00
  Hot standby IP address is 198.92.72.29 configured
  Active router is local
  Standby router is 198.92.72.21 expires in 0:00:07
  Standby virtual mac address is 0000.0c07.ac00
Tracking interface states for 2 interfaces, 2 up:
UpSerial0
UpSerial1
 

Table 1 describes the fields in the first display.

The following is sample output from the show standby command with a specific interface and the brief keyword:

Router# show standby ethernet0 brief
 
Interface   Grp Prio P State    Active addr     Standby addr    Group addr     
Et0         0   100    Standby  171.69.232.33   local           172.19.48.254  
 

Table 1: show standby Field Descriptions

Field	Description
Ethernet0 - Group 0	Interface type and number and Hot Standby group number for the interface.
Local state is ...	State of local router; can be one of the following: Active---Current Hot Standby router. Standby---Router next in line to be the Hot Standby router. Speak---Router is sending packets to claim the active or standby role. Listen---Router is neither active nor standby, but if no messages- are received from the active or standby router, it will start to speak. Learn---Router is neither active nor standby, nor does it have enough information to attempt to claim the active or standby roles. Init---Router is not yet ready to participate in HSRP, possibly because the associated interface is not up.
priority	Priority value of the router based on the standby priority command.
may preempt (indicated by P in the brief output)	Indicates that the router will attempt to assume control as the active router if its priority is greater than the current active router. This is set by the standby preempt command.
Hellotime	Time between hello packets (in seconds), based on the standby timers command.
holdtime	Time (in seconds) before other routers declare the active or standby router to be down, based on the standby timers command.
Next hello sent in ...	Time in which the Cisco IOS software will send the next hello packet (in hours:minutes:seconds).
Hot standby IP address is ... configured	IP address of the current Hot Standby router. The word "configured" indicates that this address is known through the standby ip command. Otherwise, the address was learned dynamically through HSRP hello packets from other routers that do have the HSRP IP address configured.
Active router is ...	Value can be "local," an IP address, or "unknown." Address of the current active Hot Standby router.
Standby router is ...	Value can be "local," an IP address, or "unknown." Address of the "standby" router (the router that is next in line to be the Hot Standby router).
expires in	Time (in hours:minutes:seconds) in which the standby router will no longer be the standby router if the local router receives no hello packets from it.
virtual mac address is ...	The virtual MAC address used in HSRP. This normally defaults to 0000.0C07.ACxy, where xy is the hex value of the group number. Occasionally, you may see a different MAC address that was configured using the standby mac-address command.
Tracking interface states for ...	List of interfaces that are being tracked and their corresponding states. Based on the standby track command.

Related Commands

standby authentication
standby ip
standby mac-address
standby priority preempt
standby timers
standby track
standby use-bia

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.

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, the linkUpDown notifications 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 Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 11.1.

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 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 hsrp
snmp-server host myhost.cisco.com traps version 2c public hsrp
 

The following example enables the router to send all traps to the host myhost.cisco.com using the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com public
 

The 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-relay
snmp-server enable traps envmon temperature
snmp-server host myhost.cisco.com public
 

The 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 bgp
snmp-server host bob public isdn
 

The following example enables the router to send all inform requests to the host myhost.cisco.com using the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com informs version 2c public

Related Commands

snmp-server host
snmp-server informs
snmp-server trap-source
snmp trap illegal-address

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, use the no form of this command.

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 Mode

Global configuration

Usage Guidelines

This command first appeared in Cisco IOS Release 10.0.

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.

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 hsrp
snmp-server host myhost.cisco.com traps version 2c public hsrp
 

The 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 traps
snmp-server host myhost.cisco.com comaccess snmp
 

The following example sends the SNMP and Cisco environmental monitor enterprise-specific traps to address 172.30.2.160:

snmp-server enable traps
snmp-server host 172.30.2.160 public snmp envmon
 

The following example enables the router to send all traps to the host myhost.cisco.com using the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com public
 

The 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 bgp
snmp-server host bob public isdn
 

The following example enables the router to send all inform requests to the host myhost.cisco.com using the community string public:

snmp-server enable traps
snmp-server host myhost.cisco.com informs version 2c public

Related Commands

snmp-server host
snmp-server informs
snmp-server trap-source
snmp-server trap-timeout

Posted: Thu Apr 1 12:23:46 PST 1999
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