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The Networked Infrastructure: Genlock and 10 Gb Ethernet
Paul Briscoe
Harris Broadcast
Networked Infrastructures • Evolution
–Past - minor threads of connectivity –Today - parallel systems –Future - full infrastructure
• Inverting the broadcast system cloud
Networks Past • Broadcast interconnect “cloud”
– Video, Audio, Control • Application specific network islands
– Computer graphics – Automation – Control and monitoring – Intercom
• Isolated, independent, non-standard
Broadcast “Cloud”
Network Islands
Networks Present • Parallel Clouds
– Media lives in both – Streaming distribution – File-based workflows – Contribution – Allied services
• Greater integration • Standardized methods, protocols
Broadcast Cloud
Network Cloud
Equipment
Networks Future • IT becomes the infrastructure • Islands of legacy broadcast
– Gradually replaced by IT • Support all services
– Homogenized environment – Live baseband – Production
IT Cloud
Broadcast Islands
Network Ubiquity • Broadcast equipment is specialized
– Limited selection of vendors – Price floor - volume and specialty
• IT equipment is everywhere – ‘Enterprise grade’ = ‘broadcast quality’ – Vast vendor selection (incl. quality!) – Pricing vs. volume: generic HW and SW
• Continuing trend
The File Environment • Non-realtime workflow • Large data • Simple protocols (FTP, etc.) • Constrained span • Same as a ‘regular’ IT network
The Evolutionary Facility • Hybrid operations today • Migration to live IP
–Baseband, compressed • Integrated services on the network
• Requires strong enablers
Two Network Enablers • Sync and Time (Genlock / Timecode)
–Distribution over network • 10 Gb ethernet over copper
(10GBase-T) –SDI-like baseband interconnect –Comparable physical layer
Legacy Synchronization • Video
– Switching, Mixing – Use Genlock – Black Burst or TLS
• What about audio? – DARS (AES3 / AES11)
• What about time? – Timecode SMPTE ST-12
• All are at end of life
Legacy Synchronization
Legacy Synchronization
Studio A
Studio B Edit 1
OB Truck
Edit 2 Graphics
MCR Feeds
Master Generators
�
Legacy Synchronization
Studio A
Studio B Edit 1
OB Truck
Edit 2 Graphics
MCR Feeds
Master Generators
�
Legacy Synchronization
Studio A
Studio B Edit 1
OB Truck
Edit 2 Graphics
MCR Feeds
Master Generators
�
SynchronizationTopology Master SPG
Autochangeover
First Floor Second Floor Third Floor Fourth Floor Fifth Floor Sixth Floor Seventh Floor
NW Quad SW Quad SE Quad SW Quad
STD 12 STD 13 STD 14 STD 15 STD 16
Master Control / Central Equipment Fifth Floor SW Quad STD 14
Studio Gear
Studio Gear
Slave SPG
Master SPG
SynchronizationTopology X2 Master SPG
Autochangeover
First Floor Second Floor Third Floor Fourth Floor Fifth Floor Sixth Floor Seventh Floor
NW Quad SW Quad SE Quad SW Quad
STD 12 STD 13 STD 14 STD 15 STD 16
Master Control / Central Equipment Fifth Floor SW Quad STD 14
Studio Gear
Studio Gear
Slave SPG
Master SPG
Autochangeover
Slave SPG
The Opportunity
Studio A
Studio B Edit 1
OB Truck
Edit 2 Graphics
MCR Feeds
Master Generators
� �
IP Network
Legacy Limitations • Ancient technologies (from a simpler time)
– Mix of analog and digital-ish signals
• Serious modern functional limitations • Don’t support > 60 fps, VFR • BlackBurst ≠ HDTV • Require multiple nailed-down distributions
– CAPEX, OPEX
Requirements Today • Deliver references over IP network • Provide capability of legacy systems • Provide performance for today and future • Deterministic behaviour • Provide open platform for future • Signals (transports) • Formats (essence) • Use COTS technology wherever possible
Network Characteristics • Not so good for reference delivery
– Non-deterministic • Can’t predict when things happen • Traffic all shares the road (wire, fabric)
• Packet delays are variable • Jitter!
– Things get lost
Genlock Requirements • Deliver Frequency
– Different for each signal type used – Varying degrees of tolerance
• Deliver Phase – VSync, HSync ST 318 – Audio block, frame AES3 / AES11 – Time of Day ST-12 – Date ST-309
Frequency from Time • Transferring time to a clock transfers frequency • Consider a pendulum clock • “At the tone the time is…” • Set the time • Wait a day • “At the tone the time is…” • Set the time, adjust the pendulum • Repeat
Signals from Time • Generate required frequencies • Pick an Epoch where time=0 • Define signal alignment at Epoch • Start time counter • Calculate signal phases from time
A Candidate Solution? • NTP
• Transfers time • Works on IP networks • Deterministic • Delivers time • Not enough performance
• millisecond-class time accuracy
Enter IEEE1588 PTP • Network-based Precision Time Protocol • Delivers precision time to many slave clocks • Spans hundreds of years (2177) • Sub-nanosecond granularity (12.5 ps) • Delivered over IP network • Can be globally locked (GPS, GLONASS, etc.) • Can co-exist with other traffic
Enter IEEE1588 PTP • Master and each slave
measure path delays • Slave corrects for
measured delay • Ensures all slaves are
in sync with master
Enter IEEE1588 PTP • Master sends a packet
down the stack • At the MAC layer,
timestamp is inserted • Receiving MAC
extracts timestamp • Sends it up to wait for
the packet to arrive at the top of the stack
IEEE 1588 PTP Time Count
1 Se
cond
1 M
inut
e
1 H
our
1 D
ay
1 M
onth
1 Ye
ar
1 M
illise
cond
1 M
icro
seco
nd
1 N
anos
econ
d
SDI Video
12M Timecode
Calendar
NTP
AES Audio
Composite Video
IEEE1588
GPS Native
Nanoseconds – 32 bits (1 ns)Whole Seconds - 32 bits (~136 years)
Time Counter
LSB
1 Hz(PPS)
1588 Applications
Switches get Involved • Switches introduce variable
latency • PTP switches actively
manage delay – Transparent Clock switches
recalculate time – Boundary Clock switches ‘re-
master’ time
Switches get Involved PTP
Grandmaster
Boundary Clock Switch
GPS Rx
Same time in every clock Slave
Boundary Clock Switch
Slave
Switches look like a Slave to upstream Master
Slave Clock
Master Clock
Slave Clock
Master Clock Switches look like a Master to downstream Slaves
Slave Clock
Slave Clock
Master Clock
Net Result? • Can deliver all references over IP network • Can have multiple independent systems in phase • Can share other traffic on same network
• Control, monitoring • File-based workflows • Compressed streaming • Live Baseband
One Other Thing • Timecode (= time labelling)
• 1588 offers an opportunity
• Greater granularity / span than timecode • Can label media with it
• ST12 equivalent labels possible • Any framerate / date span possible • It’s already in the equipment for synchronization
purposes • Common timestamping technology across industries
SMPTE Activities • 33TS Synchronization and Time Labeling
Standardization Committee • ST 2059 Standard Suite
– Includes EGs and RPs • ST 2059-0 Overview of Standard • ST-2059-1 SMPTE PTP Profile • ST-2059-2 Generation of Signals
SMPTE Activities • Two 33TS Working Groups • 33TS-20 is developing sync system
• Work nearing completion • 33TS-10 developing new Time Label
• Work actively underway
In Summary • Reference signal distribution – coming soon to a
network near you! • No need for independent distribution of multiple
reference signals • Can be used on same network as media • Can support all present and future types of video
and audio signals • Delivers timecode “+” for time labeling
Now,What About the Essence?
�
IP Network
Live Networked Media • ‘IT’ Networks are not ‘live’ friendly
– Reasons noted previously! • Not ‘time-sensitive’ nor traffic aware • Use retransmission to fix errors and loss
– Or • Happily accept loss
Live Networked Media • Compelling solution
– Flexibility – CAPEX / OPEX – Ubiquitous infrastructure equipment – Multifunctional
• Video, Audio, Control, Monitoring, ICM, FTP, Web, email, etc.
Networks Future • IT becomes the infrastructure • Islands of legacy broadcast
– Gradually replaced by IT • Support all services
– Homogenized environment – Live baseband – Production
IT Cloud
Broadcast Islands
The Live Environment • It’s Live! • Cannot tolerate:
– Latency (variable or too much) – Errors (no time to fix) – Outage
• Equivalent to hard-wiring • Same operational capabilities as today
Serial Digital Interface History • SD-SDI (ST 259) – Mid ‘80s • HD-SDI (ST 292) – Mid ‘90s • 3G-SDI (ST 424) – Early ’00s • Where next?
– 6 Gb? – no standard activity – yet – 12 Gb? On Coax?
Why So Popular • Simple evolutionary coax interface • Useful reach – comparable to analog • Robust and “error free” signal • Audio included • Ancillary services
– AFD, PID, Captioning..
SDI Limitations • Unidirectional • Reach drops as bitrate increases
• Technology can mitigate to some degree
• Dedicated wiring, one to one connectivity • Pipe is mostly full
– ANC data space is small!
Where to Next? • Equally capable physical layer • Available headroom • Bidirectional • Same or better error performance • Not industry-specific technology
A Possible Solution • 10 Gigabit ethernet
– Fiber or copper • Lots of bandwidth (vs. SDI) • Scalable through bonding • Becoming ubiquitous in IT world
IT Network Characteristics • Not so good for essence delivery
– Non-deterministic • Can’t predict when things happen • Traffic all shares the road (wire, fabric)
• Packet delays can be long, and are variable • Latency, Jitter
– Things get lost or resent
Protocols to the Rescue! • Protocols are coming which solve the
problems – AVB – SMPTE 2022 suite – IETF
What can 10 Gb Support? • ~33 SDI (720 x 480 / i30) • ~ 5 HDSDI (1080i30 / 720p60) • 3 3Gb SDI (1080p30) • 1 4Kp30
– Varying degrees of overhead – Bidirectional
Transport Methods • AVB
– Adjacent space to broadcasting – Developed for media over small networks – Initially compressed media only – Now being extended to high bitrates – Network Layer 2 (MAC)
Transport Methods • SMPTE 2022
– Encapsulation and transport – Provides Forward Error Correction (FEC) – Initially for compressed streams – Being updated to handle high bitrate – Network Layer 3 (IP)
SMPTE 2022 Suite
The nBase-x standards • Ethernet IEEE 802.3 root • (Speed)Base-(Media)
– 10Base-2, 5 – 10 Mb over coax, shared media – 10BaseT - 10 Mb over UTP, hub / router / switch
• Introduces the RJ-45 Connector • Extended to 100 and 1000 Mb versions • Added fiber types
Ethernet at 10 Gb • Full duplex / point to point links only
– Switched topology • no shared media = no collision loss
• Many PHY types – Copper, fiber (modes), backplane, InfiniBand – Differing media, reach, coding, modulation
10GBase-T • “IEEE 802.3an-2006” • RJ-45 (8p8c) connectors
– World’s most deployed non-power-connector type
• UTP / STP wiring – Differing reach
• Power hungry interfaces
On The Wire • Data is pre-coded for interference
avoidance • Signal on wire is PAM-16 modulated • 55M / 180 feet on Cat-5 cabling • 100M / 330 feet on Cat 6 / 6e / 7 cabling
– Existing infrastructure wiring can be used. • Can throttle down to 1 Gb
10GBase-T Power • Higher than SDI • Comparable when number of
channels considered • Declining with process geometry • Mitigation strategies
– Power tuning (length) – Green ethernet (idling) – Wake-on-LAN (snoozing)
Cabling Considerations • Standard structured IT cabling
– Cost effective • 1694A coax = ~$1.00 / foot • BNC = ~$1.25 • Cat6e cable = ~$0.36 / foot • RJ45M = ~$0.40
• Friendly legacy cabling technology
Connector Considerations • BNCs / XLRs are tough • RJ-45’s are pretty good • Ruggedization systems exist
– Reinforcement – Housing / shell (e.g. XLR body)
• Robust, weatherproof, failsafe
Power Over Ethernet (POE) • Phantom Power
– 15W / 25W / non-std (60 today) • Power management
– Sensing – Protocol
• Enables ‘single connect’ equipment
Moving the Baseband Media • SMPTE 2022
– Provides encapsulation of SMTPE standardized formats (x-SDI)
– Provides FEC protection – Specifies use of RTP for transport – Works at IP layer (layer 3)
Moving the Baseband Media • AVB (IEEE)
– Provides mapping of SMTPE standardized formats
– Utilizes protocol-aware switches • Allocate bandwidth, meter traffic
– Works at MAC layer (layer 2)
Moving the Baseband Media • AES X-192 (AES)
– Provides transport of audio – Maps AES3 – Works at IP layer (layer 3)
Compressed vs Baseband • Application
– Essence quality – Available / desired bandwidth – Tolerance of latency – Power, cost considerations
Other Services • SIP Sessions (VOIP)
– IFB, ICM, orderwire • MDCP
– SMPTE control protocol development • FTP • Email, chat, cloud editing
What about 4K • 4K res demands higher framerates
– 4Kp30 = 6 Gb/s – 4Kp60 = 12 Gb/s – 4Kp120 = 24 Gb/s
• Link bonding can achieve summed aggregate bitrates – Logically bound together
System Architectures • Will remain router-centric
– Video router becomes IP switch fabric – Everything goes through the fabric
• Connectivity reduction • One type of physical plant wiring • Hardwired equivalency by management
Timeframe? • Critical mass
– PHY power, cost – Ubiquity – Broadcast protocols, methods
• Takeoff in IT – 2013-2014 • Takeoff in Broadcast – 2014+
Standards Activities • SMPTE
– SMPTE 2022-6/7 HBRMT WG – Study Group – Networked Media Architectures – AHG – Media Device Control – SMPTE 2059 – Sync and Timing WG
• AES – X-192 audio
Standards Activities • IEEE - AVB
– 802.1AS – synchronization – 802.1 Qat – Stream Reservation Protocol – 802.1 Qav – Forwarding and Queueing for
Time Sensitive Streams – 802.1BA – Audio and Video Bridging Systems
Future Standards Activities • IEEE
– Wifi transport of AVB – AVB transport of SMPTE 2022 payloads – Interoperability between AVB / 2022
• IETF – New RTP / RTCP / SIP protocols
Summary • It’s all moving to the network.
– Get used to it. • It’s not your granddad’s network anymore.
– Network capabilities are now beginning to exceed our requirements. It’s time to strike!