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Company Confidential: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED.
Server-side WebRTC
Infrastructure
Chad Hart
Director, Product Marketing
WebRTC Japan Conference
5 Feb 2015

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 2
About Me
Sr. Director, Product Marketing Blogger & Chief Editor

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 3
Dialogic Overview
Experienced
Over 25 years connecting and adding value to Enterprise and
Service Provider Networks
Global presence
US HQ (New Jersey) / 20+ Regional offices
Strengths
Products are widely deployed
Impacting 4+ billion mobile subscribers
15+ Billion VoIP minutes / month
Excellent Support
Customers include 48 of top 50 mobile carriers and 80% of the Fortune 1000
Approximately 200 patents issued or pending
Key Product & Services
Rich Media Processing
PowerMedia: Media Server / IMS MRF / SR140
Class 4 Softswitch / IMS MGCF and VoIP Gateways
Mobile Signaling / Diameter Signaling Controllers

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 4
WebRTC Server Considerations
Signaling
NAT
Traversal
Media Gateway

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 5
WebRTC is not 100% Peer-to-Peer
Server
client client
media

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 6
WebRTC Signaling Servers Relay SDP between Clients
Real WebRTC
Session Description
Protocol (SDP)
example (partial)
Source: webrtchacks.com/sdp-anatomy

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 7
Signaling Considerations Outside of WebRTC
User authentication
Security & access
controls
Mobile push services
Federation
The rest of your
application

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 8
The NAT Traversal Problem
Image source: webrtcHacks - https://webrtchacks.com/stun-helps-webrtc-traverse-nats/

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 9
How does WebRTC Traverse Firewalls & NATs?
media
FW &
NAT
FW &
NAT
client client
10.10.1.1 192.168.10.1200.2.20.2
2
100.1.10.1
1
Signaling
Server

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Interactive Connectivity Establishment (ICE)
A protocol for establishing a peer-to-peer media connection
between peers behind NAT and firewall devices.
ICE requires 2 kinds of servers: 1. STUN
2. TURN

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 11
STUN – What is my external IP address?
Signaling
Server
media
client
10.10.1.1 200.2.20.2
2
What is my
external IP
address?
FW &
NAT
STUN
Server
Your IP address is
200.2.20.22

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 12
TURN will relay your media
media
client
Signaling
Server
TURN
Server
STUN
Server
client

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 13
Comparing STUN vs. TURN
STUN Server TURN Server
What it does?
Returns an external IP
address
Relays media
When is it needed? Almost always Rarely
How much does it
cost to operate?
Inexpensive Expensive
Does it affect voice
quality?
No Possible

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 14
Peer-to-Peer vs. Peer-to-Server
Server
client client
media
Peer-to-Peer
client client
Media Server
Signaling
Server
Peer-to-Server

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 15
Many Reasons for a Media Server
Conferencing InterworkingTranscoding
Stream processingRecording Person-to-machine

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 16
Who do You Care About More?

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 17
Bandwidth is not Always Ubiquitous or Free
Client-side Server-side

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 18
CPU & Processing Power is Expensive
Client view Provider View

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 19
Multi-PARTY! Video Conferencing

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 20
Easy & Cheap Approach to Multi-party: Mesh
20
Full Mesh
Works for a few
parties
No server cost
Lowest latency

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 21
Mesh does not Scale for Many Video Conferees
21
Full Mesh
Clients get overloaded
Encode costs more than decode
Limited uplink bandwidth
Inconsistent performance
across participants

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 22
Traditional Telephony Approach: MCU
22
Multipoint Control Unit (MCU)
Good at manipulating all media
Transcoding
Transizing
Transrating
Interworking
Server-side CPU intensive
Client can request different
conference mixes
Usually client friendly
Downsizing & mixing can
reduce bandwidth
Fewer client streams to process
MCU

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Traditional MCU Resource Usage
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Worst-case process:
1. Each stream decoded
at the MCU
2. MCU mixes each
conferee
3. MCU encodes
individual mix for
each conferee
MCU
1
1 2
2
3
3
4
45
5
6
6
Ingress streams 6
Egress streams 6
MCU decodes 6
MCU encodes 6

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 24
Efficient MCU Resource Usage
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Efficient process:
1. Each stream decoded
at the MCU
2. MCU mixes each
conferee
3. MCU shares same
encoder for all
conferees
MCU
1
2
3
4
5
6
Ingress streams 6
Egress streams 6
MCU decodes 6
MCU encodes 1
1

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 25
Resource Efficient MCU with Encoder Sharing
30%-50% reduction in compute resources
0%
20%
40%
60%
80%
100%
1 2 3 4 5 6 7 8 9 10 11 15 17 20
SystemCPUUtilization
Conferees
Encoder sharing vs. multi-encode
Traditional MCU Dialogic Evolved MCU

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Newer Approach: SFU
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SFU
Selective Forwarding Unit
(SFU) routing
Clients send one & receive
many
Client can instruct SFU which
streams to send
High throughput
Can be lots of downlink
bandwidth
Low latency

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Newer Approach: SFU
27
SFU
Selective Forwarding Unit
(SFU) routing
Clients send one & receive
many
Client can instruct SFU which
streams to send
High throughput
Can be lots of downlink
bandwidth
Low latency

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 28
New WebRTC Approach: Simulcast
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SFU
High bitrate
Low bitrate
Selective Forwarding Unit
(SFU) with Simulcast
Clients send multiple streams
to SFU
one high-bit rate
one or more lower-bit
Client directs SFU which
streams to receive
Reduces bandwidth vs. SFU
Simulcast in WebRTC coming

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 29
A look at Google Hangouts with Simulcast
http://webrtchacks.com/hangout-analysis-philipp-hancke/

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 30
Future Approach with VP9 – SVC?
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SFU
MediumHigh LowLayered bitrates:
Selective Forwarding Unit
(SFU) with Scalable Video
Coding (SVC)
Clients send layered stream to
SFU
Layers have varying bitrates –
time, size, quality
SFU directs who gets what
Coming to WebRTC eventually

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 31
Multi-party video summary comparison
http://networkfuel.dialogic.com/webrtc-whitepaper

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 32
Many Reasons for a Media Server
Conferencing InterworkingTranscoding
Stream processing Person-to-machineRecording

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 33
Case Study: Video Recording Service
Application highlights
Record live events – E.g. Kids
soccer game
Share event recording with
family/friends – Multi-party
stream
Many Recording Formats
.3GP
.mp4
.wav
Many Codecs
G.711, Opus, AMR-NB and AMR-
WB (voice)
VP8, H.264 (video)
Message Storage
Local storage
Remote message deposit via
MSRP
HTTP/
MSRP
REST (HTTP)
Application Server
Media Server
Message Storage
RTP (media)
Solution Highlights
Software-based Media Server
Virtualized (VM) and COTS deployment
High Availability and Geographical Redundancy
Scalability via Media Resource Broker
Architected to support 3.5M Subscriber Network
Recording
Remote Message
Deposit
Key Functions
Transcoding
WebRTC Signaling
WAN

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 34
Core WebRTC Gateway & Peripheral Functions
HTTP-to-SIP
(H2S)
Media GW
Transcoder
Web SIP
SBC
STUN Server
TURN Server
API Gateway
Regulates
API calls
Provides media
anchoring for
NAT Traversal
Tells a client
what its IP
address is
Converts non-
standard web
signaling to SIP
Web SDK/
Widget
Mobile SDK/
Widget
Kit for adding
Calls to
webpage
Kit for adding
Calls to native
applications
Converts one codec to
another, trans-rates/sizing
Encryption & transport
interworking
SIP interworking,
media binding, and
security

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 35
WebRTC Gateways Come in Many Packages
API Gateway H2S
Media GW SBC
Transcoder
STUN Server
TURN Server
API Gateway H2S
Media GW SBC
Transcoder
STUN Server
TURN Server
H2S
Media GW
Transcoder
SBC
API Gateway
STUN Server
TURN Server
API Gateway H2S
SBCMedia GW
Transcoder
STUN Server
TURN Server
API Gateway H2S
SBC
Media GW
Transcoder
STUN Server
TURN Server
API Gateway H2S
Media GW SBC
Transcoder
STUN Server
TURN Server

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 36
Example: Large, Web-Centric Network Architecture
Web
server
SIP/IMS
Network
SIP
Web
Media
Gateway
Firewall
APIManager
API Calls
H2S
Server
Identity
Server
App
Server
App
Server
WSS
server
STUN/
TURN
Internal
REST APIs
WebRTC
Browser

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 37
WebRTC Servers Summary
Server Type Why/when you need it
Signaling Server Required to setup a WebRTC session
STUN Server Provides NAT traversal as part of ICE protocol
TURN Server
Relays media when direct connection cannot be
established
Media Server
Provides conferencing, recording, media
interworking, transcoding, stream processing
WebRTC Gateway
Interworks signaling and media with existing VoIP
networks

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COMPANY CONFIDENTIAL: © COPYRIGHT 2015 DIALOGIC INC. ALL RIGHTS RESERVED. 38
Questions?