Cisco Systems 78-11324-02 User Manual

CHAPTER

Voice Health Monitor Overview

These topics provide an overview of the VHM application:

• Overview of VHM, page 1-2

• How VHM Integrates with Third-Party NMSs, page 1-9

• Device Types that VHM Manages, page 1-9

• VHM Support for Cisco CallManager, page 1-11

• Locating the Supported Device List, page 1-13

• How VHM Works with the CiscoWorks2000 Server, page 1-13

• Starting the VHM Application, page 1-14

• Getting Started with VHM, page 1-14

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Overview of VHM

Overview of VHM

VHM helps network administrators and network operators determine and
maintain the stability of the VoIP network within their enterprise. VHM achieves
this goal by using:

• A series of availability and health checks on the VoIP equipment in the

network.

• A fault detection and escalation system to notify the users of any faults or

exceptions detected.

VHM integrates with network management systems (NMSs) such as HP
OpenView Network Node Manager.

With VHM, you can:

• Discover VoIP network devices and applications on a user-entered schedule

• Monitor faults in voice and data networks

• Run synthetic transaction tests, to check Cisco CallManager functions

• Check the availability and health of VoIP equipment and applications

• Obtain the status of each voice device group, such as Voice Cluster, Voice

Gateway, Phone Access Switches, and Work Flow Applications

• Discover and manage Ethernet ports that have IP Phones connected to them

• Monitor IP phones in the network

Chapter 1 Voice Health Monitor Overview

How VHM Works

VHM manages the voice-specific devices in the network by polling information
from managed devices, as well as processing SNMP Traps generated by the
devices. VHM relies on DFM to receive the SNMP Traps. VHM does not
duplicate queries for information collection, but shares the information collected
by DFM.

Any polling analysis done in DFM can be leveraged by VHM. When polling
devices, DFM monitors generic parameters, while VHM monitors voice-specific
parameters. When VHM is used in conjunction with DFM, users can detect
generic faults that are causing VoIP disruptions.

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Chapter 1 Voice Health Monitor Overview

VHM correlates the collected information and generates events on voice
components that can be viewed in the Monitoring Console or on the Real-Time
Dashboard. Users can also view device level faults in the DFM Monitoring
Console. Alarms for both VHM and DFM can be seen from the Monitoring
Console.

VHM and DFM share many features as well as some components of their
architectures. VHM and its commonality with DFM are described in more detail
in the “VHM and DFM Interdependencies” section on page 1-4.

Event Correlation in VHM

Two types of events are generated by VHM: Compounds and Symptoms. One or
more Symptoms generate Compound or aggregated events. Symptoms are faults,
such as Power Supply Down or Temperature Too High, which generate
EnvironmentExceptions.Events are generated when fault conditions are detected
and the event correlation cycle is reached. The event correlation cycle in VHM
occurs every 30 seconds.

An example of an event correlation in VHM is TooManyInActivePhones. This
eventis generated when phones registered with call managers in a cluster become
inactive and cross the InActivePhoneThreshold over a number of active phones.
In this event, all the call managers in the cluster are monitored to find out the total
number of phones that became inactive and compare that number with the total
number of active phones in the cluster.

Overview of VHM

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Overview of VHM

VHM and DFM Interdependencies

Note For all DFM references in this guide, refer to the User Guide for Device Fault

Manager for more detailed information.

Device Fault Manager (DFM) and VHM both analyze Cisco device failures. The
two products often identify problems before users of network services realize that
a problem exists. Both VHM and DFM:

• Use a top-down approachthat starts with users identifying problems and their

symptoms:

–

Identify the problems affecting managed systems that are critical to
correlate.

–

Describe the symptoms, developing a “problem signature” that specifies
which conditions are present in a faulty element when the problem
occurs.

• Create a causality mapping between the problems and the symptoms.

Problems andsymptoms are coded in correlation models that VHM and DFM
use to:

–

Analyze network conditions.

–

Generate faults and exceptions.

The event information necessary to diagnose problems is present in the
correlation model. Therefore, VHM and DFM monitor only the events necessary
to diagnose problems.

Table 1-1 lists the interdependencies between VHM and DFM.

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Chapter 1 Voice Health Monitor Overview

Overview of VHM

Table 1-1 Interdependencies between VHM and DFM

Component or Feature Description of Dependency

DFM Installation A DFM version, which is compatible with VHM, must be installed

either on the same system as VHM or on a remote system where it is
network accessible to VHM. See Installing and Setting Up VoiceHealth
Monitor on Windows 2000 for server system requirements.

DFM Broker The DFM Broker maintains a list of activedomain managers running on

the network and registered with the DFM Broker. Domain managers are
fault management server processes such as VHM and DFM. Each
domain manager is identified by name and the IP address and port the
domain manager is running on.

The VHM installation process can find the DFM Broker if it is installed
locally.If not, during installation, VHM prompts the user to enter the IP
address and port for the DFM Broker. VHM then registers the VHM
domain manager with the DFM broker.

SNMP Trap Receiving To receive SNMP traps for VoIP devices from DFM, VHM must update

the trap forwarding filter in DFM. When DFM receives a trap, it
forwards the trap based on the definition of the trap forwarding filter.
The VHM trap receiver receives the trap and analyzes it to generate an
event in VHM.

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