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Video Over IP at the PBS

DDMS

Philip SchoeneSr. Dir. Engineering & Tech Maintenance

PBS

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In this Presentation

Overview of the PBS DDMS

Use of open internet for transport stream

delivery for PBS Diversity site

Comparison to dedicated EPL connection for

Disaster Recovery site

Use of Video over IP and software on COTS

hardware solution for program origination

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Overview of PBS DDMS

• Disaster Recovery – Duplicates the

capabilities of the PBS NOC

• Diversity – Uplink diversity for rain fade

protection of Ku Band services

• Maintenance – Allow for continuation of

services during high risk maintenance

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DDMS Progression

• Phased buildout

– Evergreen content playout

– Diversity uplink capability added in 2012

– Non-Real time file delivery added in 2014

– Commissioning of playout system 2014-2015

• Full transmission test on satellite

conducted December, 2015

• PBS Broadcast DR Online!

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Why a new Diversity Site?

PBS SOC –Alex.,VA

Diversity Uplink –Independent Hill, VA

DDMS UplinkPBS SOC

Previous Diversity Site

40 miles from SOC

DDMS Uplink Site

1650 miles from SOC

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Diversity System

AUTOMATION

&

PLAYOUT

MPEG4

ENCODING

DVB-S2

MODULATIONSDI ASI IF

PBS SOC

TRANSMISSION

TSoIP TO ASI

CONVERTER

DVB-S2

MODULATIONASI IF

DIVERSITY SITE

TRANSMISSION

PBS NOC - ALEXANDRIA,VA

DIVERSITY SITE - LINCOLN, NE

TSoIP

INTERNET

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Broadcast signal over open

internet service• TSoIP signals to DDMS:

66 Mbps multiple channel per carrier (MCPC)

• East coast, West coast, HD soft feed, SD soft feed

• Four 24x7 pass thru services

2 -13.5 Mbps single channel per carrier

(SCPC) services

• TSoIP signals back from DDMS:

10 Mbps multiviewer of DDMS downlinks

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What could go wrong?

MPEG4

ENCODING

TSoIP

TSoIP to ASI

CONVERTER

RECEIVED PACKETS

EXPECTED PACKETS

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What could go wrong?

TSoIP to ASI

CONVERTER

RECEIVED PACKETS

EXPECTED PACKETS

t1t2t3t4

P1P2P3P4P5P6

P1P2P3P5P6

Dropped P4

tAVG = Inter Packet Arrival Time

Dt = Jitter

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What could go wrong?

MPEG4

ENCODING

TSoIP to ASI

CONVERTER

RECEIVED PACKETS

EXPECTED PACKETS

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What could go wrong?

• Dropped packets due to congestion at

oversubscribed interfaces

• Jitter – changes in Inter-packet arrival time

• Indeterminate link latency

• Packets arrive out of order (reordered)

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Solution: Managed Service

• LTN Global operates a managed

backbone of connected datacenters

• Appliances operated by LTN manage

access to the backbone

• Buffers in the appliances allow for:

– Deterministic latency – PBS uses 200 ms

– Smooths out IPAT

– Allows for resend for missed packets

– Packets can be reordered

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LTN Appliance and Managed

BackboneLTN

APPLIANCE

#1

LTN

APPLIANCE

#2

Data Center connections

on LTN managed backbone

Managed on backbone Managed by Appliances

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Bandwidth Headroom

• TSoIP signals to DDMS:

66 Mbps (MCPC) + 2 x 13.5 Mbps SCPC = 93

Mbps

Add 25% overhead in case of resend

125 Mbps max send

• TSoIP signals back from DDMS:

10 Mbps multiviewer of DDMS downlinks

Add 25% overhead in case of resend

12.5 Mbps max return

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Internet Access Topology

LTN

APPLIANCE

A

ISP 1

ISP 2

LTN

APPLIANCE

B

LTN

ETH

SW

MUX A

MUX B

Multi

viewer

FIRE

WALL

&

DMZ

ETH

SW

PROGRAM TS

100 MbpsD/L RETURN

10 Mbps

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PBS experience

• Issue #1 – PBS Intrusion Detection

System was causing intermittent disruption

of the signal as it inspected traffic

Resolution – Bypass IDS

LTN is responsible for security of the

appliances

• Only outbound connections allowed

• Traffic restricted to specific ports

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Internet AccessTopology

LTN

APPLIANCE

A

ISP 1

ISP 2

LTN

APPLIANCE

B

LTN

ETH

SW

MUX A

MUX B

Multi

viewer

DMZ

ETH

SW

VLAN

10

VLAN

20

VLAN

10 & 20

VLAN 10 – MULTICAST

VLAN 20 - INTERNET

PROGRAM TS

100 MbpsD/L RETURN

10 Mbps

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PBS experience

• Issue # 2 - Noticed issue with how we

manage “first mile” redundancy

• PBS Networking uses Boundary Gateway

Protocol (BGP) to manage switching

between redundant first mile lSP links

– Only switches on loss of service

– No protection for excessive packet drops

– No protection for excessive delay

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Internet Access Topology

LTN

APPLIANCE

A

ISP 1

ISP 2

LTN

APPLIANCE

B

LTN

ETH

SW

MUX A

MUX B

Multi

viewer

DMZ

ETH

SW

VLAN

10

VLAN

20

VLAN

10 & 20

VLAN 10 – MULTICAST

VLAN 20 - INTERNET

PROGRAM TS

100 MbpsD/L RETURN

10 Mbps

ISP selection controlled

via BGP on

PBS Internet Routers

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PBS Experience

• Resolution: LTN given access to both ISPs

simultaneously

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Dual Access Topology

LTN

APPLIANCE

A

ISP 1

ISP 2

LTN

APPLIANCE

B

LTN

ETH

SW 1

MUX A

MUX B

Multi

viewer

PROGRAM TS

100 MbpsD/L RETURN

10 Mbps

ISP selection controlled

By LTN

LTN

ETH

SW 2

IRF LINK

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INTERNET

DISASTER RECOVERY SITE

AUTOMATION

&

PLAYOUT

MPEG4

ENCODING

DVB-S2

MODULATIONSDI ASI IF

PBS SOC

TRANSMISSION

TSoIP TO ASI

CONVERTER

DVB-S2

MODULATIONASI IF

DIVERSITY SITE

TRANSMISSION

PBS NOC - ALEXANDRIA,VA

DIVERSITY SITE - LINCOLN, NE

TSoIP

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DISASTER RECOVERY SITE

DVB-S2

MODULATIONASI IF

DDMS

TRANSMISSIONDISASTER RECOVERY SITE -

LINCOLN, NE

AUTOMATION

&

PLAYOUT

MPEG4

ENCODING

CONTENT

STORAGE NRT FILE

DELIVERY

FILE

TRANSFER

PBS MEDIA OPERATIONS CENTER,

ARLINGTON, VA

ASI

AS03

& BXF

CONTENT

PREPARATION

FILE

TRANSFERCONTENT

STORAGE

ETHERNET PRIVATE LINE (EPL)

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EPL vs. Open Internet

• Disaster Recovery site connectivity serves

many more functions:

– File transfer

– Monitoring via multicast streams PIM network

– Remote access and control of site

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EPL ROUTING

MOC

EPL POP

ROUTER

DDMS

ROUTER

DDMS

SWITCHES

ADMINISTERED

BY EIGRP

ADMINISTERED

BY OSPF

200 Mbps

EPL

GigE on

LEASED

FIBER

GigE on

LEASED

FIBER

DIV

FACs

MULTICAST

ILO OPs

TRAFFIC FOR:

- OPERATIONS

- M&C

- INBOUND MULTICAST

TRAFFIC FOR:

- OPERATIONS

(FILE

TRANSFER)

SOC

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EPL ROUTINGEPL POP

ROUTERDDMS

ROUTER

MULTICAST

SOURCES

EPL

DIV

MULTICAST

MULTICAST

RECIEVERS

SOC

PIM SPARSE

PIM SPARSE

MOC

RP

LINCOLN, NE PIM SPARSE

PIM SPARSE

SPRINGFIELD, VA

ARLINGTON, VA

OPs

FILE

STORAGE

RP

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Global Design Concepts

Use standards based solutions

General Release software based systems

built on COTS hardware

Independently redundant components

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Specific Design Concepts

Diversity system is independent of the DR

System (ingest, playout, encoding)

No PBS specific custom software

Separate redundant ethernet infrastructure

for control, multicast, diversity, facilities,

and ILO

Wherever possible, video remains in the

IP domain

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Use of Video over IP

Contribution via LTN passed to multiplexer

as multicast streams

Playout servers produce multicast for

monitoring

IRDs produce multicast streams for

monitoring

Software based multiviewers aggregate

multicast streams and produce 1920x1080

multicast for display anywhere

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Potential Future Use

of Video over IPContribution feeds direct as video over IP

to playout

TSoIP replacement of ASI to modulators

or

Playout servers produce TSoIP ready for

multiplexing

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Conclusions:

Network origination on COTS hardware

using IP video is feasible and economical

Such systems can provide benefits such

as flexibility in signal transport

Managed services over open internet can

provide reliable transport of critical signals

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Questions?

Philip Schoene – pschoene@pbs.org