How Smooth Are Your Packets?

4 DECEMBER 2018

Karl J. KuhnSr. Applications Engineer

karl.j.kuhn@tektronix.com

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

6

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

7

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

10

Video IP Roadmap

11

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

13

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

16

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

18

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

31

“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

karl.j.kuhn@tektronix.com