Ponencia de Pedro Álvarez y Pablo González (Telefónica Digital - Tuenti) VoIP2DAY 2017 http://www.voip2day.com/es/2017/conferencias/

1. VozDigital Three Years Later
Learning by doing
16/11/2017

2. Pedro Álvarez
Leads the IPComms' development teams within Tuenti, as engineering
manager. In recent years, he has been responsible for the evolution and
expansion of VozDigital throughout five countries.
Pablo González
During the last years, he has focused on evolving the VoIP infrastructure,
implementing new services and modernizing deployment processes using
technologies such as Docker.
ABOUT US

3. 3 years calling!

4. VOZDIGITAL SPAIN
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

5. PRODUCT
APP2APP
Call from application to application using
zero rating giving free communications to our
customers.
VOZDIGITAL
Call from application to any number giving as
value to customers free roaming calls, per
sample.

6. ARCHITECTURE APP2APP
Alice Bob
Chat
Server
TURN
xmpp xmpp
SRTP
SRTP

7. ARCHITECTURE VOZDIGITAL

8. CODECS
OPUS ISAC OPUS
(NB, 8k, VBR)

9. PROBLEMS
2 Architectures
Managing two different call flows is overwork and error
prompt.
App2App and VD different products
The evolution of both product is not in parallel, we can’t
develop the same features.
Platform still not stable…
¯_(ツ)_/¯

10. VOZDIGITAL INTERNATIONAL
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

11. PRODUCT
Call to any country
Customers can call international destinations
using vozdigital bundle.
● 41 Different countries
● Most popular:
○ USA
○ Italy
○ China

12. LCR
Least-cost routing
is the process of selecting the path of
outbound communications traffic based on
cost.
3487,Spain,ES,Spain,Zone1,F,IN,PROV,0.0054,1
3488,Spain,ES,Spain,Zone1,F,IN,PROV,0.0054,1
3489,Spain,ES,Spain,Zone1,F,IN,PROV,0.0054,1
346,Spain,ES,Spain,Zone1,M,IN,PROV,0.0142,1
347,Spain,ES,Spain,Zone1,M,IN,PROV,0.0142,1
3491,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
3485,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
3486,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
3487,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
3488,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
3489,Spain,ES,Spain,Zone1,F,IN,PROV,0.006,1
346,Spain,ES,Spain,Zone1,M,IN,PROV,0.0149,1
347,Spain,ES,Spain,Zone1,M,IN,PROV,0.0149,1

13. CHARGING SERVICE
Diameter-RO protocol
We provide service for both prepaid and postpaid
customers, so we need to ensure billing happens in real-
time.
Based in kamailio ims_charging module
Stateful sip proxy which performs regularly CCA requests to
make time reservations, finishing both call legs when the
customer runs out of balance.

14. ARCHITECTURE

15. VOZDIGITAL INCOMING
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

16. PRODUCT
Receive calls in the cloud (App and web)
Customers are able to receive calls in the
application, providing a full cloudphone experience.
Ability to choose modes
Users could either choose if we should try to
deliver first the calls.
Modes:
1. SIM Only
2. SIM First
3. APP Only
4. APP First
5. SIM + APP

17. PRODUCT SETTINGS
1st version, 5 options
Customer can choose one of the five modes.

18. ARCHITECTURE
Proxy
MGW
SCF
SBC Internal
(Kamailio)
Voice Router
(Java)
Voice Gateways
(Java)
SIP Balancer
(Kamailio)
Transcoders
(Freeswitch)
INVITE
100Trying
INVITE @tuenti
302 @tangle
INVITE
@
tangle
INVITE
INVITE@simIAM
IAM
INVITE
100 Trying
INVITE
100 TryingCAME
L
CAME
L
302 @tangle

19. CHALLENGES
Device reachability
Google and Apple restrict permanent connections, so we needed to provide a
push channel to notify the apps for calls, through which we don’t know if the app
is available or not in a timely manner and notifications can be lost.
Timers, timers, and timers
Failsafe mechanisms to avoid delaying the call too much, in case of timeouts
always deliver the call via GSM.
Splash ringing
For simultaneous ring, sometimes the app call arrived first and then the GSM
one, producing an annoying double call and sometimes one call cancelled the
other.

20. VOZDIGITAL PERU
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

21. NEW REQUIREMENTS
Where we deploy this country?
In order to improve performance we decide to open a new datacenter.
Support new OCS provider
We want to use the same kamailio implementation to support two OCS
specifications.

22. ARCHITECTURE

23. CHALLENGES
Configuration as system config
● Stored in puppet
● Cloned for each datacenter (Miami, Madrid) and stage (dev, pre,
production)
● Slow to apply, easy to diverge between datacenters, hard to maintain.
We needed a way to keep config aligned while keeping flexibility.
Version bump in freeswitch
To update freeswitch, old debian wheezy was unsupported. We needed a way to
make us as independent as possible from the host machine OS.

24. SOLUTIONS DOCKER

25. SOLUTIONS UNIFIED CONFIG
git
yaml
Service NodeService Node
Host nodes
├── tuenti (project)
│ ├── trans (role)
│ │ ├── mad (datacenter)
│ │ │ ├── prd (stage)
│ │ │ │ └── config.yaml
│ │ │ └── pre (stage)
│ │ │ ├── config.yaml
│ │ │ ├── trans-01 (host)
│ │ │ │ └── config.yaml
│ │ │ └── trans-02
│ │ │ └── config.yaml
...

26. SOLUTIONS TILLER
https://github.com/markround/tiller
yaml TILLER
ERB
templateERB
templateERB
template
ERB
templateERB
template
Service
config
files
Unified config
(in host machine) Service image Running container

27. VOZDIGITAL INCOMING PERU
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

28. PRODUCT
Receive calls in the cloud (App and web)
Customers are able to receive calls in the
application, providing a full cloudphone experience.
Main focus: Increase reachability
Usually GSM provides better quality, so the use-
case that adds more value is extending GSM
reception through WiFi networks.
One setting to rule them all: Sim First
In Spain the multi-setting was not well understood -
Favors autodiscovery of the feature

29. ARCHITECTURE
Freeswitch
GSM
Network
Bob
GSM
Bob
App
SBCSBC
Voice
Gateway
Chat
Server
X Paging
Tuenti infra OB infra
Internet
INVITE
To: ‘incoming’
From Alice
Diversion: BobINVITE
To: Bob
From Alice

30. ARCHITECTURE
Call Forwarding-based incoming
👎 No advanced call logic available 👍
Provides the most useful use-case
of increased reachability
👎 Initial call delay in some cases due
to GSM paging 👍 Final redirects allow for some
customization
👍 Very cost-effective
👍 Easy to explain and discover

31. VOZDIGITAL CALL SAVING
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

32. PRODUCT
Default setting and user choice
We need to provide a default setting, and the user
can change it on a per-call basis while the call is
active.
Save the whole call
They can change their mind during the call, but we
must save the whole call if the choice is affirmative.

33. ARCHITECTURE
App
Backend
Freeswitch
Processing
Queue
Processing
worker
API
* Store
preference
Call media
* Store preference
2 Retrieve
temporary file
1 Notify
end call
3 Store
converted file4 Notify new call
saving
* Anytime during the call

34. VOZDIGITAL ARGENTINA
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

35. ARCHITECTURE VD ARGENTINA

36. VOZDIGITAL FILTERS
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

37. PRODUCT
Filter the voice
We allow to the customer to make funny calls with
their friends.

38. ARCHITECTURE FILTERS

39. ARCHITECTURE FILTERS
Alice Freeswitch
Voice
Gateway
Filter
Service
Bob
Leg A media Leg B media
1,8
Tangle
DTMF
2,7
SIP
INFO
DTMF
3 4 5 6
3: Notify DTMF event
4: Send Freeswitch commands
(Retrieve files and modify
media)
5: HTTP get sound files
6: Send DTMF with result

40. APP2APP OVER VOZDIGITAL
Alice
Bob
Chat
Server
Voice
Gateway
Freeswitch
DTLS SRTP
Opus
DTLS SRTP
Opus

41. VOZDIGITAL ECUADOR
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

42. ARCHITECTURE VD ECUADOR

43. VOZDIGITAL WEBRTC VERSION BUMP
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

44. STAGING VERSION
Update WebRTC every 3 - 6 months
Always an Android device stops working, like BQ device with WebRTC 45 one of
most uses in our user base...
APK
WebRTC 59 WebRTC 60

45. CODECS
OPUS OPUS OPUS
16k

46. VOZDIGITAL GUATEMALA
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

47. ARCHITECTURE VD GUATEMALA

48. VOZDIGITAL MOVISTAR
ArgentinaVD Incoming
Peru
FiltersVDI Call Saving
Ecuador
WebRTC
Incoming
Peru
Guatemala
Movistar

49. TO BE CONTINUED...

50. QUESTIONS?
We are hiring
http://jobs.tuenti.com

51. THANKS
We are hiring
http://jobs.tuenti.com