Ready for VoIP: Network Management Architectures: Nortel Networks

Nortel Networks Corporation, headquartered in Toronto, Ontario, has a
history in telephony that dates back to 1882, when the Bell Telephone
Company of Canada established a separate department to begin manufacturing
telephone sets. That effort grew to become Northern Electric, which
designed the switching systems of the Trans-Canada telephone toll system in
the 1930s, and later became a separate subsidiary, Northern Telecom, which
was established in 1971 to manufacture and sell equipment in the United

In 1995, the Nortel brand name was established, which was
formally changed to Nortel Networks in 1999. Today, the company does
business in over 150 countries around the globe, claims the top 25 service
providers as its customers, and serves over 100 million enterprise users

The company is active in a number of communication areas, including
digital, optical, wireless, IP, VoIP, broadband, multimedia, and Ethernet
technologies. One of the largest equipment providers in the industry, the
company employs over 33,000, with around a third of these individuals
devoted to R&D activities, and posted US$11.4 Billion in revenues during

Nortel VoIP switching systems serve both enterprise and carrier class
customers, with the Communication Server family of softswitches
capable of handling over 100,000 IP phones. With systems that large, a
solid network management scheme is essential—which is what Nortel has
named its Proactive Voice Quality Management, or PVQM.

Vivinet Assessor interface
Figure 1—NetIQs Vivinet Assessor

Click to see full-size image

The PVQM solution was co-developed by Nortel and NetIQ, and is specifically designed to
ensure that the system’s voice quality is effectively monitored and
managed. PVQM is based upon a life-cycle model of IP telephony
implementation, which defines four key phases of that process:
assessment, pre-deployment, ongoing monitoring, and reporting and

The network assessment phase addresses the question: “is this network
ready for VoIP?” to determine if the current data network is capable of
handling the increased traffic loads that the voice and/or video system
will bring. NetIQ’s Vivinet Assessor is used for this phase, and evaluates
and reports on the network’s ability to support VoIP requirements, collects
network metrics to predict the overall expected call quality, and provides
an inventory of key networking devices, including switches and routers (see
Figure 1).

In the pre-deployment phase, Nortel’s Enterprise Policy Manager
provides centralized management of the network quality, making for a more
consistent QoS across the entire enterprise.

Once the network has been deployed, ongoing monitoring of end-user voice
quality and of the overall health of the network is required, which
maximizes the uptime, reliability, and quality of the connections. This
phase utilizes the NetIQ AppManager, and also the Vivinet
that combine the platform, system, and call quality metrics
for the Nortel Call Servers with information regarding the availability and
status of other network devices (see Figure 2). The Vivinet Diagnostics is
an automated troubleshooting tool that can quickly pinpoint call problems,
and assist in determining why call quality has suffered.

Vivinet Diagnostics interface
Figure 2 – The Vivinet Diagnostics

Click to see full-size image

The final phase, reporting and planning, provides voice and network
quality reporting for service level agreement (SLA) management and planning
purposes, and also utilizes the capabilities of the NetIQ
AppManager. This element of the solution allows for a number of
applications, such as IP phones, voicemail, call servers, contact centers,
and so on, to be supported from a single management console.

In addition to the NetIQ products, Nortel has embedded Telchemy’s
Vqmon agents (see in
Nortel IP phones, which allow the phone to monitor its own call quality in
real time and immediately send on RTCP XR messages for troubleshooting
analysis when predefined QoE thresholds are exceeded. (The RTP Control
Protocol Extended Reports (RTCP XR) are diagnostic packets defined in RFC
3611 (
that can be used for network management purposes.)

If a threshold is exceeded, a notification is sent on to NetIQ
AppManager and Vivinet Diagnostics, which automatically performs a
trace-route and root cause analysis while the call is in progress. Nortel’s
Enterprise Network Management System (ENMS) can then provide a
network view of the alarm and diagnostics to further isolate the
problem. In addition, Nortel’s Enterprise Policy Manager (EPM) can
be used to apply a policy to correct the cause of the network degradation
impacting voice quality.

Further details on the Nortel Networks architecture and products can be
found at Our next tutorial will
continue our examination of vendors’ network management architectures.

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