Getting the Best Out Of WebRTC - Astricon 2014

Presentation at Astricon 2014 with Tim Panton about how to get the most of of WebRTC - making sure to deal with video bandwidth, asymetric calls and remembering that things are different to typical VoIP (SIP)

Transcript

1. Getting the Best out of WebRTC Tim Panton - Protocol Droid - Westhawk Ltd
 Dan Jenkins - Chief Ape - nimblea.pe & Respoke
2. Simple 1 for 1 replacement ? No!
 Bandwidth / CPU use are different
3. How to plan a deployment A talk in two parts
4. Architecture and Choices
5. Practical numbers and graphs
6. Assumptions If you are here you are probably Doing this commercially - Quality matters Using Asterisk - Hybrid model with some PSTN Have Asymmetric calls - agents and users Are on a tight bandwidth and CPU budget Video not top priority (yet) Have a clue
7. WebRTC Topologies
8. Video Peer Calls Webservice Asterisk Agent User Internet SIP Video Audio HTML Context
9. Internal Audio Agents Asterisk L A N App Server User P S T N Agent Agent Agent Agent Agent
10. External Audio Agents I N T E R N E T User P S T N Agent Agent Agent Agent Agent WebRTC Asterisk App Server
11. External Audio Users L A N User I N T E R N E T Agent Agent Agent Agent Agent DeskPhones WebRTC Audio HTML Asterisk App Server SIP Phones
12. Hybrid L A N User I N T E R N E T Agent Agent Agent Agent Agent DeskPhones WebRTC Audio HTML Asterisk App Server Agent WebRTC SIP Phones User PSTN Audio FAX SMS Twitter Chat Email Facebook Skype
13. WebRTC issues How webRTC differs from plain old SIP ICE - can penetrate NAT at cost of setup time DTLS - encrypted traffic but call setup costs CPU Web service - may expose your Asterisk SRTP - encrypted media costs some CPU too.

14. Codecs Codecs implemented in browsers today: ULAW - old favourite - high bandwidth/ low cpu
 2 quality modes - landline or incomprehensible Opus - new comer - low bandwidth / high cpu
 flexible quality and error correction settings VP8 - free video codec - High but variable bandwidth H264 - licensed video codec - free if < 100k (IANAL)
15. Codecs - ideal choices
 (audio only) Codec Setting Reasoning P2P
 video Opus None The browser knows best Int
 Agents ulaw None low loss on LAN +
 will end up on PSTN Ext
 Agent Opus High BW / low loss Can set minimum DSL standards for staff Ext 
 User Opus Low BW / high loss Users share DSL with web/games etc Note - Digium does not support opus on Asterisk
16. DTLS - crypto selection
17. WebRTC uses DTLS to generate SRTP key Different Cypher suites Different key lengths Multiple certificate sources All impacts CPU usage at call setup.
18. ICE - Tricks
19. Assume your asterisk has a public IP Probably don’t need a TURN server Avoid offering candidates for internal IPs Don’t offer VPN candidates Can probably get away with setting ice-lite
20. Architecture - Asymmetry
21. In future we expect more asymmetric cases Mayday - they see your screen not you Baby monitor - 1 way video but 2 way audio ? Security cameras
22. What does that all mean in practice Probably: Higher CPU use (especially with Opus) Longer call setup times Very high bandwidth with Video (if enabled)
23. Tools to monitor Probably: WebRTC stats (Respoke Stats) www.npmjs.org/package/getstats chrome://webrtc-internals CollectD / Graphite
24. Some Numbers Test scenario: Asterisk: 11.8.1 on machine: Centos Intel(R) Core(TM) i3-4010U CPU @ 1.70GHz Chrome 38 Ramp up 24 calls Play back intermittent audio (IVR usage) Graph - bandwidth / CPU / calls / time
25. 24 ulaw audio calls Graph
26. 24 opus audio calls - No settings Graph
27. 24 opus audio calls Low BW high loss Graph
28. Some MORE “Numbers” Test scenario: Digital Ocean Medium Droplet San Francisco
29. 1 P2P video call - LAN/WAN http://bit.ly/dt-demo
30. 1 P2P video call - WAN http://bit.ly/dt-demo
31. Live demo using respoke Chrome (android too) browse here!
 URL: http://bit.ly/dt-asterisk
32. Thank you! Questions? More info at: github.com/danjenkins/web-examples @dan_jenkins @steely_glint www.respoke.io
33. http://upload.wikimedia.org/wikipedia/commons/c/ca/Padlock_2010.JPG http://upload.wikimedia.org/wikipedia/commons/8/8e/ Ice_road_in_the_Northwest_Territories_-a.jpg http://upload.wikimedia.org/wikipedia/commons/4/41/Asymmetric_%28PSF %29.png Images Used