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1
FTTH, Access and
Triple-Play Testing
Alfonso DomesiBusiness Development Manager
Access BU
rev.1.0, February 2011
Urbino 2011
Part 1
Last, but not least
“Last mile”
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Proprietary and Confidential 3
Once upon a time…
Proprietary and Confidential 4
Copper was first choice
BASIC COPPER PAIR TERMINOLOGY› Tip & Ring / A & B
› Ground / Earth
› CO Battery
› Wire Gauges (0.3, 0.4, 0.5, 0.6 mm) Wire Pair (or copper pair)
Ring
Tip
48 - 52VDC
-
+
RING
TIP
26 AWG
24 AWG
22 AWG
19 AWG
3
Proprietary and Confidential 5
Loop Plant: any thing is possible
Proprietary and Confidential 6
Loop Plant: any thing is possible
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Proprietary and Confidential 7
Switch on the light
Proprietary and Confidential 8
FIBER IS MADE OF DIELECTRIC MATERIAL, CONSISTING OF CORE AND CLADDING, THAT ALLOWS TOTAL INTERNAL REFLECTION OF LIGHT FOR PROPAGATION.
Coating
Cladding
Core
8mm125 mm 250mm
IOR nR
IOR nI
Fiber ‘expensive’ alternative (?)
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Proprietary and Confidential 9
Fiber Plant: any thing is possible
Proprietary and Confidential 10
The Fiber & Copper Co. gives a great flexibility to operators
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Proprietary and Confidential 11
FTTC: Just an example
Part 2
Evolution of the needs
Need an evolution
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Proprietary and Confidential 13
New app every day
Proprietary and Confidential 14
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Proprietary and Confidential 15
Access technology growth
1958 1990 1995 2005
ISDN
128 Kbps
HDSL
2 Mbps
VDSL2
100 Mbps
ADSL
8 Mbps
ADSL2+
24 Mbps
Proprietary and Confidential 16
John Cioffi, now a Stanford Professor, founded Amati and developed
Discrete Multi-Tone technology (DMT) based equipment that in 1993 had
dramatically better results than all competitors in Bellcore testing and
became the most common standard.
New era for the copper pair
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Proprietary and Confidential 17
Separates the signal
into multiples
sub-carriers (bins)
Each bin transports a piece of the
digital information
Self-adaption to the
quality of each sub-
carrier
Well defined bandwidth between
Downstream and
Upstream
The idea behind DMT
Proprietary and Confidential 18
› Number of Sub-Carrier (SC) = 256 … 4096
› SC are centered at f= 4.3125 kHz
› SNR (Signal-to-Noise-Ratio) is the key
› Dynamic Rate Adaptation
› Max number of bit per bin is 15
› Complex QAM and FFT technologies
Some DMT figures
ITU-T Rec. G.992.3 (01/2005) cp. 8.12.3.3
The signal-to-noise ratio SNR(f) for a particular subcarrier is a real value which shall
represent the ratio between the received signal power and the received noise power for
that subcarrier.
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Proprietary and Confidential 19
Flexibility, it is possible to ―switch off‖ single SC
Bit Loading, more information is sent in the SC with the best SNR
DMT bit loading concept
Part 3
Test challenge
“IPTV services”
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Proprietary and Confidential 21
0
20
40
60
80
100
120
140
160
CY08 CY09 CY10 CY11 CY12 CY13
Su
bsc
rib
er
(M)
Telco IPTV Subscribers by Type CY08-CY13
Pure IPTV Hybrid IPTV/over-the-air Hybrid IPTV/QAM
IPTV Growth
CY08 CY09 CY10 CY11 CY12 CY13
Telco IPTV Subscribers by Region CY08-CY13
North America EMEA APAC CALA
Adoption of
IPTV
Over-the-top
video is not
IPTV
Proprietary and Confidential 22
IPTV Ecosystem
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Proprietary and Confidential 23
1Digitizing
Analog content
2Encoding
Digital video
3Encapsulating in
IP packets 4Transporting
IP video content
5Removing content
from IP packets
6Decoding
digital content
7Converting
to analog
IPTV: 7 steps video process
Proprietary and Confidential 24
Digital Encoding Compression Rates
PAL Standard Definition TV video High Definition TV video
Digital Video Encoding /
Compressing format
Pre-compressed
Bandwidth Requirement
Compressed Bandwidth
Requirement
Pre-Compressed
Bandwidth Requirement
Compressed Bandwidth
Requirement
MPEG2 250 Mbps 2-6 Mbps 1250 Mbps 8-20 Mbps
MPEG4
(H.264 part 10)250 Mbps 1-3 Mbps 1250 Mbps 4-10 Mbps
VC-1 250 Mbps 1-3 Mbps 1250 Mbps 4-10 Mbps
SD image = 25 frames per sec X (576 rows X 720 columns X 24 bits)
HD image = 25 frames per sec X (1080 rows X 1920 columns X 24 bits)
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Proprietary and Confidential 25
Compression
based on processing
8x8 pixel blocks
MPEG-2 video coding
Proprietary and Confidential 26
Only changing area have to be coded
MPEG-2 video coding
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Proprietary and Confidential 27
Compression using motion vector
MPEG-2 video coding
Proprietary and Confidential 28
MPEG-2 GOP structure(GOP = Group Of Pictures)
Intra-coding
› I pictures
Forward prediction
› P pictures
Bidirectional prediction
› B pictures
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Proprietary and Confidential 29
› Transport stream (TS) is a format specified in MPEG-2 Part 1 (ISO/IEC standard 13818-
1) which contains seven packets of 188 bytes each (184 bytes of payload and 4 bytes of
packet header)
› TS can also be utilized to transport MPEG-4 encoded video
MPEG-2 TS
Proprietary and Confidential 30
The packet ID (PID) is part of that 4-byte header and represents a unique
address identifier for the type of packet or payload carried by the TS. Video
or audio packets in the stream need to have a unique PID. This allows the
decoder or STB to process the packets accordingly.
MPEG Transport Stream structureMulti-program transport stream (MPTS)
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Proprietary and Confidential 31
Header (4 bytes / 32 bits) MPEG Transport Stream structure
Source: IP Television Ma
Proprietary and Confidential 33
STBIP IP IP IP IP IPTS TS TS TS
IP IP IP IP IP IP
OpticalDSL
Ethernet/ATM
DSLAMAccess network
Head
End
CoreLast mile
Edge Last mile HomeTS = MPEG2 Transmission Stream
IPTV over the network
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Part 4
Ensuring Quality of Experience
Proprietary and Confidential 35
All is about Quality of Experience
Quality of experience (QoE) refers to the overall IPTV user experience,
including application responsiveness, functionality, usability, and the
service context that surrounds it.
Video quality of service (V-QoS) refers to the error-free video delivery
from the operator’s facilities to the customer’s premises.
Video quality (VQ) refers to the video content itself.
Analysis and Realization of IPTV
Service Quality
Bilgehan Erman and Elissa P. Matthews
Often the QoE of a customer is only known when
he calls to complain or when subscription revenue
drops needed !
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Proprietary and Confidential 36
Scope of error analysis
A/Vsource
Encoder / multiplexer
CoreNetwork
AccessNetwork
HomeNetwork
Decoder STB[1]
A/Vmonitor
Scope of the error analysis
Scope of Quality of Experience
VQ VQ
V-QoS
Video Stream QoE = (Quality of the Network Delivery System + Quality
of the Encoding Components to the Network + Quality of the Decoder
from the Network + Human Factors) per unit time[1] STB = Set Top Box
Aggregation
Network
Proprietary and Confidential 37
Quality of Experience
Video content is encoded and compressed into transport streams, which
are mapped into IP packets for transport across the network. As the
packet transitions through the network it is subject to:
› Packet Loss: loss of packets
› Jitter: variation in arrival times
› Latency: delay in packet arrival due to congestion or routing
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Proprietary and Confidential 38
Quality of Experience
Quality of Experience› Depending on which type of problem you have and which
frame is corrupted, you may experience different problems.
› Resulting in tiling, frozen frames or complete loss of picture
Jitter Effect Packet Loss Effect Out-of-order Effect
Proprietary and Confidential 39
Packet Loss
It is the failure of one or more transmitted packets [of data] to arrive at their destination and is
typically cited as a percentage.
Loss of IP packets (ultimately those carrying MPEG information) may occur for multiple
reasons
› Network congestion (over-utilization, over-subscription, hand-offs between carriers, bandwidth
limitations)
› Higher priority traffic blocking lower priority traffic
› Network equipment problems (failed switches, routers, etc.)
› Setting / configuration problems (10/100 Mbps mismatches, use of duplicate IP addresses, etc.)
› Video equipment issues (transmission errors)
› Cabling issues (wiring issues, failed links issues)
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Proprietary and Confidential 40
Depending on the type of transport protocol used for the video streaming, a packet loss will
affect the quality of the perceived video differently.
› When UDP is used, the lost packets will directly affect the image since the information cannot be
recovered and the image will be corrupt or unavailable.
› When transmission control protocol (TCP) is used, a packet loss will generate a retransmission,
which can produce a buffer underflow that may result in a frozen image.
Packet Loss
Proprietary and Confidential 41
Packet Jitter
It is the variation in arrival time between packets.› A constant rate of packet arrival is preferred
› However, the IPTV system can accept a certain amount of jitter—too much jitter will
result in lost packets.
IP IP IP IP IPIP
First Last
TX RX
Arrival Time
Ideal case with constant arrival time (no jitter), no
packet loss and no error.
IP
t2 t3 t1=t2=t3t1
RFC 3550
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Proprietary and Confidential 42
Impact on the quality
Too much jitter will result in lost packets.
The impact of packet loss on an IP video call depends upon a number of factors including:
› The percent of packet loss
› The distribution of the packet loss over time
› The capabilities of the endpoints / devices (STB)
Packet loss causes voice clipping and skips, often resulting in choppy and sometimes unintelligible audio.
IP IP IP IP IP
First Last
TX RX
Real case with not constant arrival time (packet jitter),
packet loss and errors.
IP
t1 t2 t3 t1≠t2≠t3
Proprietary and Confidential 43
› Inside the MPEG Transport Stream, it is carried out also synchronization information.
› This clock synchronization information is called PCR
› PCR info is instantaneous value or sampling of the original 27MHz system clock (STC).
› PCR info allows the MPEG decoder to recovery the original clock.
Program Clock Reference (PCR)
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Proprietary and Confidential 44
Program Clock Reference (PCR)
Video input
RX
PCR Video Audio
IP IP
27MHz STC
Video encoder DSLAM
PCR
TX
IP PCR Video Audio
Video decoder
27MHz PLL
Proprietary and Confidential 45
It is the difference between measured arrival time of last bit of the PCR counter
and the expected value of the PCR. Expected arrival time is derived from the
PCR counter value inside the MPEG packets
Program Clock Reference (PCR) Jitter
ETSI TR 101 290
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Proprietary and Confidential 46
Media Delivery Index (MDI) is an index of quality of service (QoS).
Measurements serving as indicators of problems in the network that can be proactively addressed before it becomes a service affecting issue
One of the key benefits - does not perform any type of stream decoding to achieve its metrics and therefore it does not require significant real-time processing power.
MDI uses packet level metrics so it can be used to validate network equipment such as switches and routers
Media Delivery Index
RFC 4445
Proprietary and Confidential 47
MDI and Quality of Service
MDI is expressed as Delay Factor (DF) and Media Loss Rate (MLR)
› DF indicates how long a data stream must be buffered or delayed at its nominal
constant bit rate to prevent packet loss
› MLR is a measurement of the number of lost or out of order media packets
(transport streams) over a selected time interval.
MDI Low/Good QoE
5:0
MDI Low/Good QoE
10:0MDI High/Bad
QoE
122:8
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Proprietary and Confidential 48
Broadband Core
Network Access
Network
› Set Top Box is auto-discovered by the middleware / network (DHCP) and middleware
downloads the STB client software configuration
› When customer selects a video broadcast channel, the STB launches a request
(IGMP) to connect to the appropriate IP port in the network
Home Network
Set Top
Box
Channel 208=
IP packet:
239.192.75.125
IPTV
Middleware
Head End
Customer
profile
Channel 208=
IP packet:
239.139.72.125
Set Top Box InitializationChannel Selection
Proprietary and Confidential 49
Zapping time - IGMP in Action
NETWORK
FO
X
CN
N
HB
O
IGMP
CONTROL
POINT
FOX MPEG
IGMP Leave FOX
IGMP Query
IGMP Join CNN
CNN MPEG
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Proprietary and Confidential 50
Impact of IGMP Delays
Proprietary and Confidential 51
Performance Indicators (IPTV delivery)
Parameter Acceptable Marginal Unacceptable
MDI – Delay Factor (ms) 9 to 15
* de-jittering of STB
allows for higher DF
15 - 50 > 50
MDI – Media Loss (fps) 0 .02 to .05 > .05
Packet Jitter (ms) < 5 5 – 30 > 30
Packet Loss (%) < 0.5 0.5 to 1 > 1
PCR Jitter (ms) 0 1 - 9 > 10
Zap Time (ms) < 250 250 – 400 > 400
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Part 5
EXFO solutions by application
Proprietary and Confidential 53
CUSTOMIZATION
DATA MINING
time saving
OSS integrationclose-out test
workforce automation test-head support
customer-specific tests collect results set
easy to use
OPEX
AXS-200/600
work order
job note
bluetoothtaskforce PROFILE triple play
Troubleshooting Installation Maintenance
Provisioning
IPTV service testing VoIP service testing Data service testing
Pre-qualification
The AXS-200/600 series
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Proprietary and Confidential 54
REMOTE TERMINAL
CENTRAL OFFICE
DSLAM
DSLAM
Triple Play Services
xPON
Data service verification
IPTV Analysis
VoIP Analysis
AXS-650Application
Ethernet service verification
AXS-200/650 Applications
Ethernet Triple Play Testing
AXS-650
Ethernet Triple Play testing expands products capability
Proprietary and Confidential 55
IPTV Service testing• MPEG2/4 TS, WM9/VC-1
• Bandwidth usage
• IGMP and STB Info
• IGMP Emulation
• Packet Loss, Jitter counter
• Graph & tabular output
• Zap Time
• QoS Pass/Fail Indicators
VoIP Service Testing• Monitors SIP, MGCP, SCCP
• Call Flow
• Codec indicator
• Packet Loss, Jitter counter
• Delay counter
• Graph & tabular output
• QoS Pass/Fail Indicators
Data Service Testing • PPPoE, PPPoA, IPoE, IPoA
• Tx / Rx counters
• PING, Traceroute
• WEB (HTTP) and FTP speed tests
• ATM Setup & Statistics
• VPI–VCI, OAM Loopback
RIGHT TOOL FOR PON (FTTH) !
Basic IP Service Verification• Errors, TX / RX counters, PPP, IP, DHCP & Static IP address
AXS-200/650 Applications
Fiber Optic Inspection Probe
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Proprietary and Confidential 56
Fiber Connector Inspection
› Cleaning is one of the most neglected operations but
it is the most important one
› Remember also to clean the connector which you
connect to. This must be done at LT,NT, ONT, splitter
and ODF.
AXS-200/600 Applications
Fiber Inspection Probe
Permanent damage can occur on
dirty connectors when high power
signal is turned on !
Proprietary and Confidential 57
Login
› provides PPP, IP, and bridged Ethernet encapsulation
methods and support PAP/CHAP authentication.
Ping
› user definable address, packet size and number of
attempts. Reports success or failure.
Traceroute
› user definable address, number of hops. Reports
success or failure
HTTP/FTP test
› determine access to user definable web and FTP
server address (URL or IP address)
AXS-200/600 Applications
Data
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Proprietary and Confidential 58
STB Emulation
› emulates Set Top Box (STB) for joining/leaving
channels and zap time analysis
Codec Independent
› works in environments using MPEG-2, MPEG-4,
H.264, and Microsoft codecs
Metrics
› PID Viewer, PCR Jitter, Packet Loss, Packet Jitter,
Zap Time
AXS-200/600 Applications
IPTV
Proprietary and Confidential 59
Media Delivery Index
› Supports RFC4445 (MDI) and displays Delay Factor
and Media Loss Rate. Can be used on conjunction
with the EXFO FTB-8510B which provides MDI
measurements in the network core
QoS Pass/Fail
› Quickly see whether the circuit passes or fails based
on user definable thresholds
AXS-200/600 Applications
IPTV
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Proprietary and Confidential 60
Monitor
› Monitor VoIP calls to ensure correct Caller ID, call
flow, and codecs (G.711, G.729, G.726, G.723)
Metrics
› View Packet Loss, Jitter, and Delay distribution
graph
QoS Pass/Fail
› Quickly see whether the circuit passes or fails
based on user definable thresholds
Counters
› Duplicated or Out Of Sequence packets, Invalid
received packets
AXS-200/600 Applications
VoIP
Thanks !