1. Delivering Serverless IP Telephony to the Enterprise Simon Bryden VP Engineering, Popular Telephony

2. What's wrong with servers? They're expensive o High start-up cost o Typically high maintenance/support overhead Initial learning curve o Blocking factor for small businesses Single point of failure o loss of server impacts all clients

3. A Tempting Proposition... User Manual Step 1: Unpack phones Step 2: Plug them in Step 3: Start calling

4. Serverless Architecture

5. Serverless Challenges How to route calls? Call state tracking Storage o address books o voicemails o call registers Feature implementation System administration

6. Data Storage Storage on local terminals o ties terminals to people o use broadcast-based retrieval Distributed storage o access from any terminal o resilient to loss of terminals o DHT-based storage/retrieval

7. Distributed Hash Tables Used to map a data object to one or more nodes Each node has small number of peers Peers forward requests to their peers Typically order log 2 (n) hops to retrieve data Extremely scalable

8. Distributed Hash Tables At startup, new peer needs to find existing peers Several mechanisms o IP multicast o Registration point o Preconfigured ranges o Cached lists

9. Data Storage - details key=”login:100” data=”sip:100@192.168.0.100” key hash=>node 7 Node 1 Node 7 Node 8 Node 9 Node 6 Node 5 Node 4 Node 3 Node 2

10. Data Storage – conceptual view key=”login:100” data=”sip:100@192.168.0.23

11. Distributed Intelligence Terminals must understand features Call control more complex o compared to standard IP phone

12. Example Call Flow Login as “100” login:100 sip:100@192.168.0.23

13. Example Call Flow login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 Login as “101”

14. Example Call Flow login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 Request “login:101” Dial “101” sip:101@192.168.0.35 100 101

15. Example Call Flow login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 100 101

16. Feature Example: Pickup login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 ring:sales 101 100

17. Feature Example: Pickup login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 ring:sales 100:101 Request “ring:sales” Pickup 100 101 103 “100:101”

18. Feature Example: Pickup login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 ring:sales 100:101 Redirect to 103 login:103 sip:103@192.168.0.19 Delete ring:sales 100 103 101

19. Feature Example: Pickup login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 101 100 103

20. Feature Example: Pickup login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 100 101 103

21. Feature Example: Park login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 park:385 100 Park ID = 385 Park 100 101 103

22. Feature Example: Park login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 park:385 100 Call Parked 100 101 103

23. Feature Example: Park login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 park:385 100 Call Parked Request “park:385” Unpark 385 100 101 103 100

24. Feature Example: Park login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 park:385 100 Call Parked Reconnect with 103 Delete “park:385” 100 101 103

25. Feature Example: Park login:100 sip:100@192.168.0.23 login:101 sip:101@192.168.0.35 login:103 sip:103@192.168.0.19 100 101 103

26. Roadblocks DHT implementation very complex o Need 100% guarantee of data location o Need strong reliability o Limited storage on nodes o Limited performance nodes New features = new software o Need a good auto-update feature

27. Summary P2P telephony is the future High-interest topic o Vendors already shipping products o IETF involvement o Some open source interest Natural evolution

28. Thank You