Networking Fundamentals - We are SMPTE...2019/12/12 · •Enterprise Networking, Security, and Automation •Essentials of IP Media Transport for Broadcasters •Understanding SMPTE

2019-12-12

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SMPTE Essential Technology Concepts

© 2019 • SMPTE® | Enabling Global Education • www.smpte.org

Networking Fundamentals

For ST 2110 and Internet Streaming

Russell Trafford-Jones

Your Host

Joel E. Welch

Director of EducationSMPTE


2019-12-12

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SMPTE Virtual Courses

• Internetworking• SMPTE is a Cisco Networking Academy

• Introduction to Networks

• Switching, Routing, and Wireless Essentials

• Enterprise Networking, Security, and Automation

• Essentials of IP Media Transport for Broadcasters

• Understanding SMPTE ST 2110

• Other courses:• Imaging System Fundamentals

• IMF Essentials• HDR Technology and Workflows for Media and Entertainment

• More coming in 2020!

© 2019 • SMPTE® | Enabling Global Education • www.smpte.org 3

SMPTE Essential Technology Concepts

• Series of ten 60- to 90-minute online planned for 2019

• Designed to present the fundamental principles and concepts that are

foundational to the technology and workflows in media & entertainment

• Interactive webcasts

• Free to everyone

• Sessions are recorded for on-demand playback

© 2019 • SMPTE® | Enabling Global Education • www.smpte.org© 2019 • SMPTE® | Enabling Global Education • www.smpte.org

2019-12-12

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Housekeeping

• Please indicate you want to ask an oral question by indicating such in the chat box

• If you do not have a microphone, please submit your questions via text

• SMPTE provides a PDF of select slides used during webcasts in exchange for your feedback

• Once your feedback is submitted, you will automatically be redirected to the PDF for downloading

• Please feel free to post or blog about today’s webcast on your social media platform of choice

@smpteconnect

#SMPTEWebcast

© 2019 • SMPTE® | Enabling Global Education • www.smpte.org© 2019 • SMPTE® | Enabling Global Education • www.smpte.org

Views and opinions expressed during this SMPTE Webcast are those of the presenter(s) and do not necessarily reflect those of SMPTE or SMPTE Members.

This webcast is presented for informational purposes only. Any reference to specific companies, products or services does not represent promotion, recommendation, or endorsement by SMPTE


2019-12-12

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SMPTE Technology Webcast SeriesSMPTE – Enabling Global Education


Broadcast EngineerTechex

EditorTheBroadcastKnowledge.com

Today’s Speaker



Aims

• Help you talk about and understand relevant networking

• Video production

• Video distribution

• Understand how and why packets move

• Find out what makes video/audio special for networks

• Allow you understand which topics you need to look into more

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Topics

• How can we get computers to talk to one another?

• Building complexity with a simple, layered approach - OSI model

• Physical Connections

• Networked computing

• Delivering video on

• high-reliability networks

• the internet with streaming

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Two Computers in a Room

• How might they communicate?

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Hello?

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The OSI Model

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Layer 7 – ApplicationLayer 6 – PresentationLayer 5 – SessionLayer 4 – TransportLayer 3 – NetworkLayer 2 – Data linkLayer 1 – Physical


Defining Terms

• Packet

• like an envelope of data

• Provides some structure around the data/payload

• NIC – Network Interface Controller

• This is the network socket that the cable plugs into

• Cabling

• CAT 5, 5e, 6, 7 & 8

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Layer 1 – Cabling

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RJ45 Fibre Category 8 cable


Layer 1 complete

• How can the message travel on the wire?

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Hello?

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Layer 1 complete

• With multiple computers, like people, we need names.

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Bob Jane

Hello,Jane

Hello,Bob


Layer 2 – Ethernet

• Gives an address to each NIC

• MAC address: b8:27:eb:c3:62:9c

• Always 6 pairs of hexadecimal numbers

• Vendor code + Unique code

• Can be set by the user in some circumstances

• Without Ethernet and MAC addresses, we don’t have computer-to-computer messages.

• So we can’t have a network.

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Now we can talk

• Using ethernet, they can talk

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MAC address: 00:00:00:00:00:01 MAC address: 00:00:00:00:00:02


OSI - Looking at Layers

• Each layer below is transparent to the current layer

• IP Computers just think they are next to the computer the need

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Layer 3

• Built on top of Layer 2, the datalink layer.

• Enables route finding between two computers not directly connected;

• Called the network layer

• Allows for sending to computers on the other side of the world

• Based on an ARP table

• arp -a

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What is an IP Address?

• 4 numbers linked by full stops

• e.g. 120.140.221.18

• Total possible approx 4.3 billion

• Private addresses:

• 172.16, 10., 192.168

• All dropped by internet routers

• Allows safe, internal-only operation of networks

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What is an IP Address?

IP Address standard details:

IP: 10.18.41.200

Subnet: 255.255.255.0

Gateway: 10.18.41.254

• A subnet defines which addresses are on your network

• A gateway address is a device which is on two networks

• Allows your data to get out of your network

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How do you get an IP address?

• Manually

• DHCP

• Automatically given from a pool

• Can be reserved against MACs

• Most ISPs give dynamic addresses by default

• If you want a public IP address your company has to be linked to your computer, this is best done by port forwarding.

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Now we can talk

• Using IP, we can network together

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IP Address: 192.168.1.1Subnet Mask: 255.255.255.0

MAC address: 00:00:00:00:00:01


MAC address: 00:00:00:00:00:02


Now we can talk

• Using IP, we can network together

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MAC address: 00:00:00:00:00:01


MAC address: 00:00:00:00:00:02

Gateway

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Summary

• Have looked at how to connect computers together

• How to talk over a cable

• How to get from one computer to another, anywhere.

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Layer 4 – TransportLayer 3 – NetworkLayer 2 – Data linkLayer 1 – Physical


The OSI Model

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Making a network for broadcasting

• Typically need to send from the source to many receivers:

• Video playout needs to get to several monitors plus a vision mixer

• Network bandwidth is not infinite, particularly for HD ST 2110, we have video streams of over 1Gbps.

• So far we would need to send 5 copies to 5 end-users.

• Wasteful and creates a bottleneck on the receiver end,

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Multicast

• Broadcast, for networking, means sending once and being received by all

• Unicast means sending once and being received by one receiver only.

• Multicast is the middle ground; send once, any number of receivers can opt in to receiving it.

• Maximum efficiency

• Done with…

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IGMP

• Internet Group Management Protocol

• Creates groups you can join or leave

• IP addresses such as 239.x.x.x reserved for multicast

• IGMP v2 and v3

• Source-Specific addressing (232.x.x.x)

• Network partitioning

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Making a network for broadcasting

• Can now send video efficiently from place to place

• Data needs to arrive in a timely fashion

• Network architecture needs attention

• Jitter needs to be low

• Can’t wait long for the next packet

• Time between packets is important

• Difficulty recreating timing

• Buffers underflow

• IAT - Interpacket Arrival Time

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© 2019 • SMPTE® | Enabling Global Education • www.smpte.org 32


The OSI Model

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Using SMPTE ST 2110

• We are very close to being able to implement ST 2110

• Now we need to work out what type of messages to send

• High bandwidth

• We need a light-weight way of transferring data

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UDP - User Datagram Protocol

• Connection-less best effort delivery

• “Fire and forget”

• Very low overheads

• Unidirectional traffic

• Great for low latency applications

• Uses ports to differentiate traffic

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RTP – Real-Time Transport Protocol

• Extension of UDP

• Includes sequence number and time stamp in the header that allows a receiver to see lost and out of order packets

• Required for SMPTE 2022-7 seamless switching

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ST 2110 Roundup

• We now have the building blocks for implementing a simple 2110 system

• We have high speed cabling

• Devices can communicate with the next device

• IP routing allows data to get to any device

• Multicast networking minimises bandwidth

• We use RTP wrappers to send data

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Moving down the broadcast chain

• ST 2110 deals with high-bandwidth essences

• As well as metadata!

• Our requirements for delivery to the home are different but built on the same foundations.

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Streaming Online

• On the internet, life is different

• Multicast barely exists

• More likely to have lost packets

• More likely to have delayed packets

• OTT streaming needs to deal with all of this

• TCP has a solution to these problems

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TCP - Transmission Control Protocol

• Packets are sent with an associated sequence number

• Every packet is acknowledged by the receiver

• If no acknowledgement is received after a certain amount of time the packet is resent

• Used in HTTP, POP3, SMTP

• Uses ports to differentiate traffic

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HTTP & HTTPS

• HyperText Transfer Protocol

• Built on top of TCP

• Session based

• Allows delivery of files based on requests from clients

• The basis of the web

• Use port 80 and 443

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Chunk the stream

• Cut your video stream into 10-second chunks

• Encode each of those chunks into a single file with video & audio

• Write a quick text file (manifest)

• Download, using HTTPS each chunk over TCP

• Start playing them one after another

• Enjoy seamless video

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Chunked streaming

• Pros

• ‘Perfect pictures’ – picture quality is never compromised by transmission loss/errors.

• HTTP is widely deployed and understood

• Can use MPEG-2 Transport Streams

• ABR

• Cons

• High latency

• There are nuances in the encoding

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HLS & DASH

• We have outlined these two protocols.

• Built on HTTP

• Used for all websites

• Uses TCP ports 80 or 443

• Lot to know about the above, but networking is done

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Aims - Review

• Help you talk about and understand relevant networking

• Video production

• Video distribution

• Understand how and why packets move

• Find out what makes video/audio special for networks

• Allow you understand which topics you need to look into more

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Summary

• The same 4 layers of networking underpin both ST 2110 and online streaming

• Complex systems are created out of distinct, simpler, layers

• The choice of UDP/TCP transforms the performance of the network.

• We’ve outlined the important elements to understand in any move to IP…and where to continue our studies.

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Thanks!

Questions are always welcome!

LinkedIn: Russell Trafford-Jones

LinkedIn: The Broadcast Knowledge

Email: [email protected]

Twitter: TBKnowledge

Web: https://TheBroadcastKnowledge.com

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SMPTE Technology Webcast SeriesSMPTE – Enabling Global Education


Broadcast EngineerTechex

EditorTheBroadcastKnowledge.com

Questions?


Documents

Networking Fundamentals - We are SMPTE...2019/12/12 · •Enterprise Networking, Security, and Automation •Essentials of IP Media Transport for Broadcasters •Understanding SMPTE