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W.R.
Skoglund, Business Development
Manager - Telecommunications,
Sierra Monitor Corporation
One
of the largest cable network operators in the
southeast had historically delivered analog
video (cable television) services to its customers.
Network infrastructure included a main building
in a given service area and numerous remote
Network Equipment Buildings throughout the service
area. Video services were delivered via coaxial
cable.
In
1998, the company embarked upon the major initiative
of delivering broadband services to its customers.
The existing cable network, with appropriate
capacity to be added as necessary, would be
used to deliver digital telephony, high speed
data and digital video services. In offering
the critical content of digital telephony and
high speed data, the company recognized the
need for a dramatic improvement in network reliability
and service quality. Service outages needed
to be minimized to the lowest possible level.
Consistent with that need, the first Local Network
Operations Center (LNOC) was to be implemented.
The LNOC would institute surveillance of network
elements that provide and support broadband
services.
Cable
Network Reliability
In the original cable network, video services
were delivered via coaxial cable from a head
end in the main building through remote structures
located throughout counties, cities and neighborhoods.
The remote structures are either Hub buildings
or walk-in cabinets. Hub buildings are the larger
of the two structure types, fully above ground
and designed to blend aesthetically with the
local area or neighborhood. The Hub buildings
house more cable equipment and are used in larger
service areas with larger numbers of subscribers.
The walk-in cabinets are partially underground
with above ground door access and considerably
lower profile than the Hub buildings. However,
the type of equipment deployed is the same.
Environment
controllers are used in these structures for
management of space temperature and other ambient
and security parameters. Were an alarm condition
to occur, the controller would generate an alarm
locally within the structure. Generally, these
structures are not manned, and therefore, the
alarm would go unnoticed until such time as
the alarm condition caused a service interruption.
The service interruption would precipitate customer
calls to alert the company to the problem. An
example of a critical environmental alarm is
high temperature. Walk-in cabinets are equipped
with two air conditioners. An air conditioner
could fail and go unnoticed until a failure
of the second air conditioner, causing the structure
to overheat. High temperature-induced equipment
malfunction would then cause a service interruption.
To
deliver broadband services, it would be necessary
to install fiber optic cable from the head end
to the Hub buildings and walk-in cabinets. Fiber
would also be installed from the buildings and
cabinets to nodes from which coaxial cable would
run to customers' homes. Each node would service
approximately 1,000 homes on four trunk lines.
Since the buildings and cabinets are the through
points for the fiber, they needed to be equipped
with the additional equipment necessary to support
optical transmission.
With the concurrent deployment of equipment
for delivery of broadband services and implementation
of the LNOC, the company defined two objectives
essential to the required improvement in service
quality and reliability:
• Complete a system wide evaluation of
network monitoring and alarm systems to determine
how to identify infrastructure and facility
weaknesses before they caused system failures.
• Design a network monitoring system incorporating
remote monitoring of structures to enable LNOC
surveillance of network elements.
LNOC
Surveillance System
Early in the system wide evaluation of network
monitoring and alarm systems the company focused
on local monitoring already in place. Five walk-in
cabinets in a county service area were equipped
with Environment Controllers managing space
temperature, ventilation, response to combustible
or toxic gas build-up, smoke detection and structure
security. Again, however, alarms were not being
monitored beyond the cabinets.
The
company contacted the manufacturer of the controllers,
Sierra Monitor Corporation, to further explore
their capabilities. They learned that the controllers
were not limited to environmental monitoring
and alarms, but could be expanded to manage
alarms critical to broadband equipment such
as telephony and video equipment rack fuses,
power supplies and back-up power generators.
The controllers were also equipped with dial-up
modems whereby they could afford remote interrogation
and configuration capability and dial out automatically
in the event of alarm condition. However, this
would require the use of a dedicated telephone
line to the controller in each structure. The
company preferred to monitor the structures
over their existing wide area network (WAN).
To implement this final step to the solution,
Sierra engaged the resources of their FieldServer
Technologies Division. FST designs and manufacturers
the FieldServer Bridge, a protocol translator
that enables data transfer between serial and
Ethernet protocols. The FieldServer Bridge would
become the key element in the transfer of data
to the LNOC.
The
LNOC was in the implementation stage and was
not equipped with the appropriate database and
graphics software to efficiently manage data
from the many remote structures. Sierra Monitor
Corporation proposed to supply the host computer
running the HMI and alarm handling software.
The database and computer screens would be fully
developed by Sierra. The delivered product would
be a fully commissioned LNOC Surveillance System.
System
Description
The first step in the implementation process
was to identify those specific points and parameters
to be monitored in the remote structures when
they were equipped with broadband delivery equipment.
For each structure, points lists were developed
to add equipment monitoring to the existing
environmental monitoring. The points lists defined
the necessary analog and digital inputs, control
outputs and alarm outputs required of the environment
controllers. The points lists then defined the
requirements for expansion of existing controllers
and needs for new controllers.
The
next phase of engineering focused on the FieldServer
Bridge to be installed in each structure to
act as the communication link between the environment
controller and the company's WAN. Two software
drivers needed to be installed in the Bridge:
the serial protocol driver for the environment
controller and the Ethernet driver for the WAN.
Selection of the Ethernet driver was a function
of the HMI and alarm handling software to be
installed on the host computer in the LNOC.
Intellution FIX was the software of choice,
dictating the Modbus TCP Ethernet driver. Both
drivers were available in a large library of
drivers written and maintained by Sierra.
Working
closely with the company's engineering and technical
support staff, Sierra developed the complete
database and the HMI and alarm handling screens.
The primary screen is a regional map, with secondary
screens showing NEB locations in counties within
the region. Should an alarm condition occur
in an NEB, an audible alarm is activated in
the LNOC and the county location of that NEB
flashes on the regional map. Clicking on the
flashing county name zooms to the county map
with the NEB location generating the alarm condition
flashing.
 Clicking
on the NEB location displays a screen showing
a plan view of the inside of the NEB with all
monitored points and parameters shown graphically.
In a walk-in cabinet, for example, the plan
view illustrates the access door (open or closed),
equipment rack locations with color coding for
those that are monitored, status of critical
environmental parameters, e.g. smoke detector,
floor water level and status of environmental
controls, e.g. air conditioning, ventilation.
Superimposed on the screen is a graphic displaying
structure internal temperature and relative
humidity as well as concentrations of toxic
and flammable gases for personnel safety.
Depending
upon the alarm conditions, various tradespersons
may be involved in resolving the problem at
the NEB. For example, an air conditioner technician
would be required to respond to an HVAC alarm
condition, but a telephony or video technician
must respond to a rack fuse alarm. Complicating
the response is the need to dispatch a specialist
based upon the geographical location of the
NEB. To accomplish efficient call-out procedures,
a software package (WIN-911) is installed on
the LNOC overlaying the graphical (HMI) interface.
The WIN-911 package allows every individual
alarm condition to be linked to a specific announcement
protocol. The announcement will include a voice
simulated message over the speaker in the LNOC
control room and a dial out to the pager of
the appropriate response personnel. A table
of names, responsibilities and pager numbers
is maintained in WIN-911 and each HMI alarm
is linked to the appropriate name in the table.
The
plan view (overview) screen is one of four screens
available for each NEB. Using index tabs on
the screen, the LNOC operator is able to select
the overview, photo, instructions or configuration
screen. The photo screen displays a photograph
of the NEB. The Instructions screen displays
instructions on how to respond to various alarm
conditions. The Configuration screen allows
the LNOC operator to configure set points such
as air conditioner on and off, high temperature
alarm, high humidity alarm, etc.
 Irrespective
of alarm conditions in a given NEB, each screen
in the HMI is designed to convey overall network
alarm status and facilitate easy navigation.
The footer to all individual NEB screens is
a listing of all current network alarms, indicating
date, time, location and type of alarm, acknowledged
or unacknowledged. Buttons on each screen afford
instantaneous access to network alarm status
and history. Buttons also afford easy navigation
from county to county or from a county to the
entire region. In the main building, several
environment controllers and Bridges are deployed.
Each is in a zone with an individual screen,
e.g. first floor head end, first floor switch
room and co-location. Again, buttons are provided
for easy navigation from one zone to another.
Sierra
Monitor Corp. provides regular modem based system
support for staged sectional start-up and for
upgrades, changes and trouble resolution. To
accomplish this support, a modem and a third
party remote access software package are installed
in the LNOC host computer. Sierra support personnel
can use this package to dial in from a remote
location, generally Sierra Monitor Engineering
in Milpitas, Calif. to access the host computer.
Data files can be downloaded to the host computer,
field server bridges can be accessed, upgraded
and reconfigured, controllers can be operated
via Telnet and field diagnostics can be implemented
down to the controller level. The remote access
connection assures rapid response, allows the
involvement of the appropriate system specialists
and eliminates support personnel travel costs
and associated delays.
Benefits
to Customers
The benefits of the LNOC Surveillance System
to subscribers derive directly from the benefits
to the cable network operator:
• Remote surveillance of unmanned, critical
network elements to enable immediate response
to problems
Power
supply and temperature alarms are critical.
Either can cause widespread disruption of service.
Without remote monitoring capability, only the
reported service outage would alert the company
to the need for dispatch of service personnel.
The problem would then have to be identified
at the structure in order to perform corrective
maintenance. This could entail significant delays
in restoring service to the customers. With
remote surveillance, power supplies and temperature
are monitored continuously and trouble conditions
or alarms are communicated to the LNOC instantaneously
upon occurrence. Consequently, the time to restore
customer service is dramatically reduced.
• Analysis of network data and alarms to
enable deployment of appropriate service personnel
The
company uses redundant equipment frames in a
hierarchy based upon how crucial the service.
Video is extremely critical since all three
services, digital telephony, high speed data
and digital video, "ride" on video.
Combiners in the network insert the proper frequencies
to support the particular services of given
customers. Redundancy, therefore, is highest
on video and progressively less on telephony
and data. In the LNOC Surveillance System, network
elements are monitored down to the rack fuse
level for all services. When a fuse alarm occurs,
the LNOC is instantly alerted, the impact on
service is analyzed and, through the WIN-911
system, the appropriate telephony, data or video
technician is dispatched to the site. By monitoring
the individual network elements supporting the
full array of broadband services, the company
is able to offer its customers maximum availability
of all services and rapid, service-specific
response to interruptions.
• Proactive identification of issues that
could impact delivery of services prior to an
interruption of customer service
In
addition to specific network elements, the LNOC
Surveillance System monitors NEB support systems
critical to proper operation of the entire structure,
including air conditioning, battery back-up
and back-up power generators. Redundant air
conditioning affords the capability to monitor
each air conditioning system individually, alarm
to failures, maintain proper structure temperature
with the redundant system and implement corrective
maintenance prior to high temperature-induced
equipment failure and subsequent service interruption.
In the event of primary AC power failure, the
48 VDC power plant will sustain equipment operation
for 4 hours. During that period, however, AC
powered devices such as air conditioning are
disabled. Therefore, back-up power generators
are automatically brought on line. The structure
environment controllers manage automatic switchover
to generator power and the LNOC Surveillance
System monitors critical generator parameters
such as generator fuel, oil pressure and temperature
to alert to the need for maintenance prior to
shutdown, loss of power and possible interruption
of customer service. Again, the key benefit
to the customer is maximum availability of services.
Contact
Sierra Monitor at www.sierramonitor.com
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