How Smooth Are Your Packets?
4 DECEMBER 2018
Karl J. KuhnSr. Applications Engineer
Implementation Realities
and
Best Practices of IP and PTP
2
Don’t Worry- It‘s Digital- It Just Works!!!
• Analog Degrades Gracefully◦ It Tells You All Its Aches and Pains
◦ Window into Electronic World
◦ Drifts Over Time
◦ Analog Can Work When Very Impaired
◦ You Decide
• Digital Has Cliff Effect◦ It Tells You Nothing –
◦ Digital is Analog but Digital Decides
◦ Baseline
◦ Intensive Care Ward
◦ EVERYONE Has This All Figured Out
◦ Interoperability – All Devices are Guilty
◦ Big Circuit Board
◦ Testing is Too Expensive
2
3
High Level Testing Concepts- Analog vs Digital
• Quality of Service (QoS)◦ Perhaps Totally Transparent to End User
◦ Luma Chroma Audio Levels
◦ Bandwidth
◦ Transmission Latency
◦ Jitter and Wander
• Quality of Experience (QoE)◦ The End User Will Notice and The Phone Will Ring
◦ Long Access Times
◦ Buffer Wait Times
◦ Black Frames
◦ Freeze Frames
◦ Blockiness
◦ Slice Errors
◦ Loudness and Level Issues
◦ Closed Captioning
3
Why do we still use SDI?
• SDI works very well indeed
◦ Plug and Play
◦ Bit perfect pictures
◦ High Availability
◦ Extremely low latency and jitter
◦ Frame accurate switching is inherently simple
• A unidirectional “thin” protocol that is extremely easy to deploy
• SDI is an open, non-proprietary and universally supported standard
IP MIGRATION
• Born IP – Delivered IP
• Reduce the total system cost
◦ COTS (Commercial Off-the Shelf) products
◦ Less number of cables, Lighter truck
• Prepare for the future
◦ Multi format support
◦ Reconfigure the system easily without replacing most equipment
• Ubiquitous Accessibility
◦ Cloud operation
Why are we moving to IP?IP MIGRATION
Black Burst Tri Level and SDI is last holdoutMERGING TOGETHER: IT AND BROADCAST ENGINEERING
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IT Engineer
• IP Flow, Protocol, Network traffic, Configuration
• NTP and PTP
• Less sensitive to the impact to the quality from a bit
error
• Data can be reset- not the case with Video
• QoE centric mythology
• Challenge in understanding the video technology
Video Engineer
• SDI, Analog, Audio
• Black Burst and Tri Level Sync
• Importance of delivering signal quality
• QoS centric methodology
• SDI vs IP IP is an Abstraction
• Challenge in understanding the IT
technology
Need Reporting Monitoring and Analysis tools
for QoS and QoE in hybrid facilities
SDI Video Plant
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IP Video Plant
8
IP packets
carrying
video
TimePerfect Stream
Low-Jitter on Video over IP
Point to Point Jitter is low
9
TimeEveryone Sharing the
Same Pipe
Higher-Jitter on Video over IP
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Video IP Roadmap
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ST 2022-6 SDI Encapsulation over IP
ST 2022-7
AES 67 - AES audio Encapsulation over IP
VSF TR-04
ST 2110 -10,20,30,40
IEEE1588 > ST 2059 PTP Precision Time Protocol
Image
Data
Meta
Data
RFC
4175
VSF TR-03
IETFRTP
ANC
IS-04
AMW
A
NMOS
ST 2110 -50
Sender Receiver
Hitless Switchover ST 2022-7
• Switches use IGMP
• Clean Switch Using Frame Numbers
Stream
Sender A
Duplicate
Stream
Generic
SwitchPacket
Selection
1 2 3
1 2 3
1 2 3
1 2 3
1 2 3
x x
Basics of ST2110
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We finally get to get rid of blanking!
Basics of ST2110
14
ST2110 defines a set of streams that are transported
individually, but may be timed together.
Basics of ST2110
15
This means we can have a separate audio stream, separate
video stream and separate ancillary stream.
They may or may not be on the same wire.
Session Description Protocol (SDP) files keep them
together- for RTP, SDP files as our ‘manifest’. Senders expose an SDP file that
describes the location of the Sender’s RTP stream. Note: other information in this SDP
file is also used by the In-stream Identity and Timing Specification, which includes
example SDP files.
Basics of ST2110
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7 basic definitions◦ 2210-10: system timing
◦ 2110-20: video
▪ 2110-21: video distribution in time (timing model)
◦ 2110-30: audio
▪ 2110-31: support for legacy AES3 (in progress)
◦ 2110-40: Ancillary data
◦ 2110-50: ST2202-6 with AES67 audio and ST2059-1/2 for timing (in progress)
Synchronization Accuracy• Accuracy traditionally is based the smallest element of the video
• Analog Video (NTSC)
◦ approx. 800 picoseconds
◦ one degree of Subcarrier
• Digital Video (SDI)
◦ Within a pixel
◦ 13.5 nanosecond for HD Rates
• PTP
◦ time accuracy between two slave devices to master within 1μs
◦ Accuracy enough to align the datagramsIP
SRC
IP
DST
RTP Header w/
TimeStamp
Video Payload
ST2110
ST 2110 Timing
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PTP
Reference
Clock
2110 Enabled Device
Internal
Clock
1 6 3 4 2 2 5 60 6 7 2 2 8 3 2
Zero Offset Zero Offset
Video Datagram Audio Datagram
0 6 7 2 2 8 3 2 RTP Timestamp 1 6 3 4 2 2 5 6
0 6 7 2 2 8 3 2 1 6 3 4 2 2 5 6
4 DECEMBER 2018
PTP Network
Transparent
Switches
Boundary
Switches
Backup
Network
Primary
Network
Redundant System, Air-Gapped
20
Spine
Leaf
Spine
Leaf Leaf
Spine
Leaf
Spine
Leaf Leaf
Client Client Client Client Client Client
Network 1 Network 2
Redundant System, Cross Connected
21
Spine
Leaf
Spine
Leaf Leaf
Spine
Leaf
Spine
Leaf Leaf
Client Client Client Client Client Client
Network 1 Network 2
PTP Spine – Leaf Network
22
Spine
Leaf, BC
Spine Spine Spine
Client Client Client Client Client Client
Network 1 Network 2
PTP BCLeaf
PTP BCLeaf
PrimaryPTP Master
BackupPTP Master
PTP only
Leaf, BC Leaf, BC Leaf, BC Leaf, BC Leaf, BC
First Step to Troubleshooting PTPVERIFY THE SETTING OF THE GRANDMASTER (GM)
• Setting of all the slave clocks need to match the setting of the GM• Domain
• Domain is defined a number from 0 to 127• Profile
• General Profile send Sync commands .5perSec• AES Profile send Sync commands 1per Sec• SMPTE Profile send Sync commands 8 per Sec
• Communication Mode• Multicast,• Unicast• SMPTE Mixed Mode
4 DECEMBER 2018 23
Verify PTP DomainYOU NEED TO KNOW THE DOMAIN YOU ARE TROUBLESHOOTING
• Domain is defined by a number from 0 to 127• Verify all devices are in the correct PTP Domain (0 to 127)
• In order for Devices to share PTP commands they need to be in the same Domain• Each Domain will have a Grandmaster Clock
Note:
If you do not know what the Domain
Check your GM settings or
Capture a Pcap File of the Stream
with the Prism or WireShark.
Each PTP IP packet will have the
Domain value.
PTP Status
WireShark4 DECEMBER 2018 24
Verify PTP ProfilePROFILES HAVE DIFFERENT ANNOUNCE AND SYNC INTERVAL
PTP Status
• The three Profiles use in Broadcasting are:
General Profile send Sync commands 1perSec
AES Profile sends Sync commands 4 per Sec
SMPTE Profile sends Sync commands 8 per Sec
• There are other differences between the Profiles
• SMPTE has a mixed communication mode
• Mixed Mode uses both Multicast and Unicast
4 DECEMBER 2018 25
Verify Sync Messages Rates(THIS CAN SHOW NETWORK ISSUES
DROPPING THESE MESSAGES COULD CAUSE LOCKUP PROBLEMS)
Active FieldsCounts number of
messages per Sec.Active Fields
Prism’s IP Session Display / PTP Tab4 DECEMBER 2018
Verify Switches Support MulticastPTP USES A DEFAULT MULTICAST ADDRESS (224.0.1.129)
• PTP aware device should automatically join the PTP Multicast▪ Announce, Delay-Respone,& Follow-UP messages uses port 320
▪ Sync & Delay-Request messages uses port 319
• Port 319 carries the time sensitive messages
SPG8000a PTP Status
Prism IP Status Display show
the two ports used by PTP
4 DECEMBER 2018 27
Verify the PTP Grand Master(GM)BEST MASTER CLOCK ALGORITHM (BMCA) DETERMINES THE GM
• Master based on several parameters that are carried by the Announce
• Priority 1 (Default Value 128)
• Lowest value wins (Range 0-255)
• Use to exclude devices from being
able to be the GM
• Clock Class
• Clock Accuracy
• Clock Variance
• Priority 2 (Default Value 128)
• Lowest value wins (Range 0-255)
• Use to designate user default GM
• Final tie breaker
• Clock ID usually MAC address
Verify Master ID Matches desired GM
BMCA Values from the GM
IP Session Display / PTP Tab
Denotes quality
of GM Lock
4 DECEMBER 2018 28
Verifying Video Lock in the IP worldJUST LIKE BASEBAND VIDEO YOU NEED THE SIGNALS TO SYNCHRONIZED TO A
COMMON REFERENCE
PTP Timing Display
4 DECEMBER 2018 29
PTP Graphing
304 DECEMBER 2018
RTP Sequence error / CRC error
• “Isolate the root cause of CRC error ”
◦ An error in IP layer causes RTP Sequence
Error and CRC Error
◦ An error in SDI layer causes CRC Error Only
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“NEED MULTILAYER TROUBLESHOOTING METHODOLOGY”
4 DECEMBER 2018
4 DECEMBER 2018 32
ST 2110-21 Traffic Shaping and Delivery Timing
4 DECEMBER 2018 33
ST 2110-21 Traffic Shaping and Delivery Timing
4 DECEMBER 2018 34
ST 2110-10 Stream Timing
4 DECEMBER 2018 35
ST 2110-10 Stream Timing
4 DECEMBER 2018 36
ST 2110-10 Stream Timing
4 DECEMBER 2018 37
ST 2110-20
PIT Histogram ST2110
4 DECEMBER 2018 38
4 DECEMBER 2018 39
ST 2110-20
12/4/2018 40 OF 24
Test Equipment Justification Process
Where Do We Start?
• Continuous Learning
• Stay Current
• Get Management Buy In
• Elevator Pitch
• Fight for Budget Line Item
• Current Wish List
• Persistence!!!!!!!
12/4/2018 41 OF 24
Test Equipment Justification Process
What is the Cost of Not Testing ?
▪ UNKNOWN UNKNOWNS
▪ Quality Impacts and Rework
▪ Not Meeting Delivery Specification
▪ Missed Schedules and Budgets
▪ Advertising Revenue
▪ Legal Contract Issues
▪ Life and Death
▪ Truck Roll, Churn, Customer Service Issues
▪ Unknown Good/Bad Parts Sitting on Shelf
▪ REAL COST When Something Goes Wrong
12/4/2018 42 OF 24
Test Equipment Justification Process
Speaking to Management
• Management Might be Non Technical/Non Creative
• Management by Spreadsheet
• Speak in Business Terms
• Cost Cutting/Saving Money- ROI
• Make Their Pain Go Away
• Cost of Not Testing
• Write an Easy to Understand Justification
• When Test Equipment Saved the Day Share the Good News
• Once You Acquire Gear USE IT
• Make sure Management Sees You Using Test Equipment
• Read the Manual
• In your Weekly/Monthly Report Tell How Gear Saved the Day
12/4/2018 43 OF 24
Test Equipment Justification Process
Understand Why-What-Where You Need to Test
• Analog Video and Audio
• SDI and IP Video and Audio
• Compressed Content
• File Based Content
• RF and/or GigE Transport of Content
• Referenced Human Vision System Based Video Evaluation
• Unreferenced Video Quality of Experience
• ALWAYS HAVE A WISH LIST READY
12/4/2018 44 OF 24
Test Equipment Justification Process
How You Benefit on a Personal Level
• Build Self Confidence
• Pro Active not Re Active
• Less Stress
• Reduce Finger Pointing
• Less Wasted Time
• Increase YOUR WORTH to the
organization
• Stay Employed
• Enhance Your Resume
How Smooth Are Your Packets?
Implementation Realities and
Best Practices of IP and PTP
4 DECEMBER 2018
Karl J. KuhnSr. Applications Engineer