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Next Generation Converged Network
Michel Béland
Michel Béland joined CBC/Radio-Canada in 2005 as a Senior Technologist in the
Advanced Systems Development & Integration Group within the Strategy and Planning
Department of CBC/Radio-Canada Technology. During his time there, he worked on
many Special Events projects such as the Helsinki Games as well as the Turin and
Beijing Olympics designing remote production systems. He was also part of the team that
designed and built the HD Hockey Night in Canada edit and presentation suites in
Toronto. He is now part of the Telecommunications Group, where he is a Senior
Manager and responsible for NGCN System Design and Development.
Introduction
CBC/Radio-Canada adheres to a centralcasting model for broadcasting, which means that
its regional stations contribute content to a central location, Toronto for English Services
and Montreal for French Services. Regional content is assembled along with national
content and returned to the regions, so that it can all be sent to the local transmitter for
broadcasting.
On the business side, corporate data occupies an important place in CBC/Radio-Canada’s
day-to-day operations. This includes email service, Internet access, FTP file transfers,
and SAP, amongst others.
An appropriate method of transportation was chosen depending on the nature of the
content: this could be Asynchronous Serial Interface (ASI), analogue, or Standard
Definition (SD) Serial Digital Interface (SDI) circuits for video exchange locally or
between cities, or satellite service for national contribution or collection. Integrated
Services Digital Network (ISDN) and analogue audio circuits were used for radio
distribution and collection. Telus provided a Multiprotocol Label Switching (MPLS)
network for the corporate data and some FTP file transfers.
CBC/Radio-Canada has relied on national and local carriers to provide services for media
and data exchange between CBC/Radio-Canada sites, including local loops. With longterm contractual agreements coming to an end, the Corporation wanted to explore the
possibility of using a single network to carry audio, video, corporate data, and FTP file
transfers, as well as answer any future needs, such as teleconferencing, IP telephony, and
remote productions for special events.
Following this requirement, the Next Generation Converged Network (NGCN) was
born. This network offers flexibility and scalability, and it ensures efficient use of
available bandwidth. The NGCN currently provides connections between forty
CBC/Radio-Canada sites as well as eight data-only sites, five of which are airports and
the other three are Pippy Place, SSO Carling, and the Network Alarm Centre (NAC).
As services expand and new stations are built, the NGCN will cover those services
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whenever possible. Remote regions remain a challenge and will continue to be serviced
by satellite and other alternative means accordingly.
Context
Network Implementation
CBC/Radio-Canada’s broadcast model is one of collection or contribution followed by
distribution. To better understand the network implementation part of the NGCN, let’s
first take a look at how the old model worked. On the collection side, content was sent
from regional stations or remote locations through terrestrial and satellite real-time
networks to the Toronto Broadcast Centre (TBC) and/or la Maison de Radio-Canada
(MRC), as seen in figures 1 and 2.
CBC/Radio-Canada: Satellite TV Collection Network
Ku-Band
ANIK FIR
T23(E) or
T24 (F)
ANIK FIR
9A or 12A
C -B a
SNG
Truck
SNG Trucks
(Upload
Content)
nd
Ku-Band
B
C-
REGIONAL
STATION
d
an
Steerable
Downlinks
(C or Ku)
C-Band
REGIONAL
STATION
Fixed
7.3m
Antenna
(C & Ku)
Canadian
Press
TBC or MRC
Figure 1 – Satellite Collection Network
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ETN Presentation/Collection Network
B. Clark
17 Aug 04
Drawing-V3.vsd
Replacement of Anik F1/12A with Terrestrial Fiber
Anik F1/C-Band
ETN Television Service
FTN Television Service
Collection/Contribution Channels
Proposed New Circuit
Bell Proposed Transponder 12A Replacement
Existing Distribution or Collection
xx
Proposed Circuit Cancellation
Unit
Source
Prov
Destination
Prov
Monthly
Annual
OTC
12A-8
EDMONTON
ALTA
TORONTO
ONT
5,921
71,052
1,300
12A-7
CALGARY
ALTA
TORONTO
ONT
5,863
70,356
1,300
12A-6
REGINA
SASK
TORONTO
ONT
4,765
57,180
1,300
12A-5
WINNIPEG
MAN
TORONTO
ONT
4,429
53,148
1,300
12A-4
FREDERICTON
NB
TORONTO
ONT
3,686
44,232
1,300
12A-3
CHARLOTTETOWN
PEI
TORONTO
ONT
13,067
156,804
1,300
12A-2
HALIFAX
NS
TORONTO
ONT
4,193
50,316
1,300
12A-1
ST JOHN'S
NFLD
TORONTO
ONT
27,507
330,084
1,300
* Above Video circuits are 24/7, terrestrial
Total
69,431
833,172
Anik F1/Ku-Band
Hfx/ATHAT1Ftn/ATF
Van/PTV Wpg/CTW
PT1
Mtl/ETM Reg/STR
MTN ETM
Sktn/STS
Edm/MTE
PTN
MTN
Syd/ATS Cgy/MTC
PTN
St.J/ATJ Tor/ETT
Occ
Chtn/ATC
FTN
Radio
11-channel
SCPC
8-PSK
Ch-A1
Radio
Digital
Ch-A2
SCPC
Ch-D1
Distribution
Ch-A3
FTN/Ch-A1
QPSK
Radio
Distribution
(Temp)
Ch-M1
TBA
‘FTNMUX’
2A
10,400
6A
Ch-E1
ETN-1
FTN-1
Collector
Collector
Ch-H
Ch-E
ETN-2
FTN-2
Collector
Collector
Collector
Ch-K
Ch-M
Ch-M2
7A
Ch-G
Ch-D
Collector
Collector
Ch-L
ETN-3
FTN-3
Collector
Collector
12A
T-24
9A
T-23
Anik F1 --- Existing Channel
Utilization
15-Channel
Multiple, TDM stream
Current Leased Inventory :
5 x C-band Transponders
2 x Ku-band Transponders
Local Supper-hour Show (Canada Now)
3 x C-band
(D1,E1,L)
2 x C-band
(D1,E1)
2 x Ku-band
(ETN1,ETN2)
Ykn
Moncton
Toronto
Teleport
NPB
Syd
A31
Gillin
A2-RS
A30
Cornerbrook/
Gander
B20
A90
A1-R
(A,B)
TOC
Van
4 x C-band
(D1,E1,G,H)
Edm
CBC-5
A5-SA
A25
A25-A
Sktn
A3-SR
CBC-6
A8
A24
3 x C-band
(D1,E1,K)
TOC
ANW-C2
Cgy
TOC
Reg
TDM Local Loop
(Installed Aug/00)
Windsor
A6-R
NCC/Distribution
Switcher
2 x C-band
(D1,E1)
CBC
Toronto
...
DVC
Encode/Mux
Ott
TOC
Chtn
Hfx
A3-R1
ANW-H2
Presentation
...
3 x C-band
(D1,E1,L)
1 x Ku-band
(ETN3)
PICR
PICR
PICR
...
St.J's
BHFX-R3
A2-RC
A3-T
A2-RF
2 x C-band
(D1,E1)
Fctn
TOC
A2-R
...
Mtl
A3-R2
Wpg
A37
A25-B
A38
A5-T
TOC
3 x C-band
(D1,E1,L)
1 x Ku-band
(ETN2)
5 x C-band
(D1,E1,G,H,K)
A38-A
A39
A40
A3-E
A5-U
Saint John
12A-5
12A-3
MCR/NCC
12A-4
12A-6
12A-2
12A-8
12A-1
12A-7
ANW-C1 (Newsworld, 1300 - 1700 EST)
A9-R
A3-A
A9
A3-B
Wash
Lond/UK
TOC
A3-U
Figure 2 – Satellite and Terrestrial Collection Network
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On the distribution side, televised content from the TBC and MRC was sent by satellite to
regional stations to reach the off-air transmitter through a Studio Transmitter Link
(STL), and distributed to cable and satellite providers as well as isolated transmission
sites, as shown in figure 3.
CBC/Radio-Canada: Satellite TV Distribution Network
NIMIQ 1 & 2
(ExpressVu) &
ANIK F1R
(Starchoice)
ANIK FIR
2A (E) or 6A(F)
Off-Air
Transmitter
REGIONAL
STATION
DTH
Satellite
Operators
TERRESTRIAL
TERRESTRIAL
STL
Tx
C-Band
Off-Air
Transmitter
Signal Pass
Through
C-Band
Videotron
Rogers
Shaw
Tx
Sites
Fixed
7.3m
TBC or MRC
Cable
Operators
ExpressVu or
Starchoice
Headend
Figure 3 – Satellite Distribution Network
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When dealing with radio content, collection and distribution was done mainly through
land-based networks. An example of the 1P English Radio collection network is shown in
figure 4.
COLLECTION
CBU
VANCOUVER
(STU)
EDMONTON
CFGB-FM
GOOSE BAY
(STU)
POC
CBX
EDMONTON
(STU)
VANCOUVER
POC
CORNER
BROOK
GRAND
FALLS
GANDER
CBCT-FM
CHARLOTTETOWN
(STU)
GOOSE BAY
CBA
CBY
CBT
CORNER BROOK GRAND MONCTON
(STU)
(STU)
FALLS
HALIFAX
(STU)
POC
CBVE-FM
QUEBEC
MONCTON
(STU)
CBQT-FM
SAINT-JOHN
THUNDER BAY
POC
(STU)
REGINA
POC
CBK
REGINA
(STU)
WINNIPEG
POC
THUNDER
BAY
CBN
ST-JOHN'S
(STU)
CBHA-FM
HALIFAX
(STU)
SYDNEY
CBI
SYDNEY
(STU)
CBD
SAINT JOHN
(STU)
TORONTO
POC
MONTREAL
POC
CBE
WINDSOR
(STU)
CBG
GANDER
(STU)
CBZ
FREDERICTON
FREDERICTON
(STU)
QUEBEC
CBW
WINNIPEG
(STU)
CBL-FM
TORONTO
(STU)
A7.5
CHARLOTTETOWN
CALGARY
POC
CBR
CALGARY
(STU)
1P
01PNNC9000
2005-08-29
CBM-FM
MONTREAL
(STU)
OTTAWA
POC
WINDSOR
CBO-FM
OTTAWA
(STU)
Figure 4 – 1P English Radio One Switched Broadcast Collection Network
Each location could receive content and insert content into the network; this service was
provided by Bell.
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On the data side, the MPLS Cloud served as the corporate data network and was also
used for some FTP file transfers and Internet access services.
Figure 5 – Data Network
The NGCN was designed to replace the satellite collection infrastructure and part of
distribution network, with the goal of freeing up transponders 9A and 12A on the Anik
F1 satellite. It also replaces the radio collection network. The new network is composed
mostly of a fibre optic network and, in regions where fibre with Synchronous Optical
NETwork (SONET) service is not yet available, Ethernet Private Line (EPL) is used.
The NGCN also replaces the MPLS Cloud for data services. Multiple services converge
onto a single network connecting CBC/Radio-Canada sites across the country, as well as
London in the UK and Washington, D.C., in the USA.
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Figure 6 shows the configuration of the NGCN for current and future CBC/Radio-Canada
sites. The sites are categorised as core, branch, TV/radio, radio-only, and data-only sites,
which include airports for the distribution of CBC News Express.
Figure 6 – NGCN Network
The yellow boxes represent the thirteen core sites to which branch sites and all other
types of sites connect. The core sites are meshed to allow data to flow through an
alternate path in case of failure of the most direct path. The core sites also have protection
in the form of diverse routing of a working and alternate path, as well as a diverse
entrance of the protected fibre into the site building. This type of protection was also
implemented at other non-core sites whenever possible and cost effective. Refer to the
legend in figure 6 for the type of protection as well as the bandwidth for every link.
Another detail to point out from figure 6 is the grey boxes around the Toronto and
Montreal nodes. They show that both these sites have the equivalent of two nodes per
site. The second node is located in a second Central Equipment Room (CER) in each
location, and it belongs to a completely redundant architecture from the one in the first
CER. Other sites also have redundancy; however, main and redundant architecture are
located in the same CER room in those cases. This additional spatial redundancy was
added to Toronto and Montreal for disaster recovery purposes, given that they are the
network heads for English and French Services respectively.
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The network provider is Rogers and its fibre network adheres to the SONET standard.
The EPL segments are IP type networks over fibre or copper.
The protected OC-192 links between Montreal, Toronto, Ottawa, and Quebec City are
fully redundant links, meaning that a copy of the data flows through both working and
alternate paths of the links simultaneously. All other protected links work in a 1+1
configuration where, if the working path fails, then the data is switched over to the
alternate path.
Bandwidth Requirements
Bandwidth requirements for each site were based on TV supper hour show needs in terms
of the number of audio/video feeds required for the production of the show, plus the
Radio requirements, contribution feeds, and the data requirements in terms of corporate
data, including Avid and Dalet FTP file transfers, all whilst taking into account the
number of users and production volume at the site.
For video, the HD format was used in the calculation. For good measure, a yearly
increment of data traffic year after year for the contractual period was also factored into
the bandwidth calculation.
Another factor that went into the bandwidth requirement calculation was the
consideration of a total link failure between two core sites. In that eventuality, the traffic
needs to be directed through an alternate path, which must be able to handle the increased
bandwidth from the core site and all of its branch sites.
For instance, extra links were added between St. John’s, Newfoundland, and Halifax and
Moncton to bear the extra load in case of a link or site failure related to one of these two
sites. The extra links will be used to compensate for the extra bandwidth.
Supported Formats
For video, standard and high definition SDI video with embedded audio are supported as
a source format and compressed using JPEG 2000 format. Two J2K encoding profiles are
used, one for SD video with compression set to a bit rate of 50 Mbps with 2 AES
embedded audio pairs, and HD video with a bit rate of 100 Mbps with 4 AES embedded
audio pairs. Special custom profiles are also available for special cases. The resulting
signal type from the J2K compression is an ASI signal. Other ASI signals from MPEG 2
and H.264 video encoders can be transported by the NGCN, as long as these ASI signals
are decoded by their respective decoders at the receiver end. An example of this might be
the use of the NGCN to transport an MPEG 2 encoded signal originating from a mobile
truck at a remote site.
The JPEG 2000 standard uses a wavelet compression technique and works at
compressing each frame rather than working on a Group of Pictures (GOP) as with
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MPEG 2 and H.264. The result is low encoding and decoding latency. Subjective testing
helped determine the encoding profiles for SD and HD video that were used in the
bandwidth calculations.
Audio uses AES as a source format and it is transported in AES format without any
compression. The bandwidth allotted to the audio is 3.4 Mbps for an AES pair. If the
plant only supported analogue audio, analogue to digital and digital to analogue
converters were installed.
Data, which is in the form of IP packets, is comprised of a mixture of corporate data
(GroupWise, SAP, network storage, Internet, etc.) combined with Avid and Dalet file
transfers, as well as network and equipment management to name a few. At each site, the
IP routers are assigned a minimum and a maximum data bandwidth. When audio/video
services are in low usage, then the extra bandwidth is used by the data services; the
routers are throttled up and down accordingly. Priority is given to real-time audio and
video, and then to FTP file transfer services.
Equipment
The equipment required to interface to the NGCN is divided into three categories: the
Broadcast Interface Equipment, Network Interface Equipment, and Network Transport
Equipment. The Evertz Advanced optical Transport Platform (ATP) was chosen for
this function.
Figure 7 – NGCN Equipment
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The Broadcast Interface Equipment is the equipment required at the NGCN demarcation
point to transform the input and output signals to and from a format that is handled by the
Network Terminal Equipment if need be.
The Network Terminal Equipment consists of video/audio mux and demux devices that
handle up to eight signals or channels and of two or eight port IP interface devices. The
switch fabric, known as the ALR, routes individual video, audio, datacom, and telecom
signals to and from selected sources and destinations on the network. The trunk interfaces
connect the ATP to the transport network. Figure 8, courtesy of Evertz, illustrates this
concept.
Figure 8 – ATP Hardware Components Shown with Sample Signal Types
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Trunk interfaces come in a variety of flavours and are available for SONET/SDH
(Synchronous Digital Hierarchy) or IP. The SONET standard is used in North America
and the SDH standard is used everywhere else. The following table summarises the
designations and bandwidths for these standards.
Payload
Bandwidth
(kbit/s)
SONET
Optical
Carrier Level
SONET
Frame
Format
SDH Level &
Frame
Format
OC-1
STS-1
STM-0
50,112
51,840
OC-3
STS-3
STM-1
150,336
155,520
OC-12
STS-12
STM-4
601,344
622,080
OC-24
STS-24
–
1,202,688
1,244,160
OC-48
STS-48
STM-16
2,405,376
2,488,320
OC-192
STS-192
STM-64
9,621,504
9,953,280
OC-768
STS-768
STM-256
Line Rate
(kbit/s)
38,486,016 39,813,120
Table 1 – SONET/SDH Designations and Bandwidths
The Network Transport Equipment is the network switching equipment provided by
Rogers for connecting to the local Point of Presence (POP), and it resides at
CBC/Radio-Canada’s premises in the case of large and medium-size sites. In the case of
smaller sites, the switching equipment resides at the POP.
Wave Division Multiplexing (WDM) is used to transport signals to a POP from a
CBC/Radio-Canada location requiring connections to multiple cities, a principle that is
illustrated in figure 9. The trunk interfaces encapsulate outgoing traffic into SONET
frames and de-encapsulate the SONET frames to retrieve incoming traffic. All the trunk
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interfaces operate with a laser set to a wavelength of 1310 nm. Outbound signals are
shifted to a different wavelength and then optically multiplexed onto the transmit fibre of
the fibre pair connecting the CBC/Radio-Canada site to the POP. At the POP, a
Reconfigurable Add Drop Multiplexor (ROADM) device extracts each wavelength
from the fibre and routes it to the Rogers inter-city core switch, whence it is sent to
another inter-city core switch at the POP in the other city as part of one of many signals
multiplexed onto a larger pipe.
Figure 9 – Wave Division Multiplexing
At the receiver end, the process is reversed. Establishing a connection between Toronto
and Montreal for example, means that Toronto can send to Montreal and vice-versa. The
full bandwidth of the link is available in both directions.
System Management
With such a large system deployed across the country, including locations in Washington
D.C. and London (UK), a management tool to monitor the devices, modify settings when
needed, and upgrade components when new features become available is a necessity, and
it must be able to do this from any CBC/Radio-Canada location through a network
connection. Evertz provides such a tool and it is called VistaLink Pro. VistaLink Pro is a
client application that runs on a standard PC and connects to the VistaLink Pro central
server.
An optional component to VistaLink Pro is the Alarm Server, which manages alarms
generated by the components to detect such things as a component removal or insertion in
a frame cage, a link loss, loss of audio, loss of video, over-provisioning of a link, and a
plethora of other conditions. There is quite a bit of flexibility as to what can be set to
trigger an alarm. Media Network Operations (MNO) has also configured Simple
Network Management Protocol (SNMP) monitoring to poll ATP devices, IP switches,
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and routers on the network, and to automatically generate a problem ticket to the
Network Alarm Center (NAC). Problems reported by users are also directed to the
NAC and then dispatched to the MNO Network Operations Center (NOC) team for
troubleshooting.
Resources
Resources use ScheduLink from ScheduAll, the time and resource management
scheduling application, to create bookings. The application has been modified to receive
return codes from the Evertz Intelligent Resource Manager (IRM) application that
serves as a third party application interface to ATP Scheduler, which is the Evertz
scheduling application. These return codes indicate the status of each booking through its
lifecycle. If for some reason ScheduLink is not available, bookings may be created
directly in IRM.
One interesting aspect of the ATP platform is its ability to multicast or send a source to as
many destinations as required simultaneously without requiring extra bandwidth per extra
destination. Figure 10 shows an example of multicasting as seen in ScheduLink. The
London (UK) feed is sent to Toronto and Montreal simultaneously. The London optical
connection is with Toronto, but, when the signal arrives in Toronto, the ALR switching
matrix routes the signal as well towards Montreal without doubling the bandwidth
between London and Toronto.
Please note that figure 10 is a logical representation of a multicast in ScheduLink. The
signal, as explained above, makes its way to Toronto first and then is routed to Montreal.
Figure 10 – Multicasting
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Conclusion
The NGCN system officially started carrying production signals on September 1, 2011.
Since then, it has enabled both English and French networks to complete their centralised
radio presentation onto the NGCN and, consequently, the Bell circuits are no longer used,
aside from some local loops that were planned to be kept. The data migration was
completed in December 2011.
Moving forward, a new station in Rimouski, Quebec, will come on line on the NGCN in
April and be ready for full operation by September 2012. An NGCN mobile node was
designed and built, and it is being tested to address Special Events needs. It currently
connects to a Montreal node where trunks provide audio, video, intercom, and control
connections to a choice of one of several studios to do remote production similar to what
was done during the Turin and Beijing Olympic games, but on a smaller scale.
Some locations that were radio-only have requested to add video contribution capability.
We have also added ASI send and receive capability in both Toronto and Montreal. A
permanent lab is in the design stage for Montreal, Toronto, and the Evertz facilities in
Burlington, Ontario. This three-node system connected through Rogers’ fibre network
will allow us recreate every situation and condition of the production system, and to test
new software and firmware releases before applying these to the production system.
We have seen a marked improvement in the quality of the video, audio, and data
exchange rates for file transfers, not to mention the ease of use of the system when it
comes to setting up services to send content to a neighbouring city, or across the country
to a single destination or to several destinations simultaneously. As such, the NGCN
offers unparalleled flexibility and scalability.
There is no doubt that the NGCN is a Next Generation Converged Network that will
enable CBC/Radio-Canada to seize great development opportunities in the future.
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