Expanding internationally presents challenges related to signaling, media quality, and numbering. Signaling challenges include establishing calls and interoperating with carriers globally. Media quality challenges include delay, jitter, and audio artifacts due to long distances. Numbering challenges involve different numbering conventions in different countries. To address these, the document recommends deploying media capabilities everywhere through border gateway proxies and relays to minimize latency, enable features like recording and DTMF mid-call, and transcode between incompatible carriers. Carriers generally do not support reinvites or peer-to-peer media.

1. Expanding Internationally
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Challenges & Solutions
Jonas Borjesson
Tech Lead – All things SIP
jonas@twilio.com
@borjessonjonas

2. Challenges
● Signaling
● Establishing the call
● Connecting/interop with carriers around the world
● Media (Audio Quality)
● Delay
● Jitter (drop-outs)
● Strange audio artifacts
● Numbering
● People are used to certain number series
● Different laws around the world
jonas@twilio.com
@borjessonjonas

3. Latency
● Make sure that media takes the shortest route
possible – no matter where the users reside
● Less latency
● Minimizes risk for jitter
jonas@twilio.com
@borjessonjonas

4. Things can change!
● Have to be capable of changes mid-call
jonas@twilio.com
@borjessonjonas

5. Deploy Media Capabilities
Everywhere
● Essentially: carrier
● B2BUA:s for traffic
● Relays for media
lb
● Note:
● Carrier is not re-invited b2bua
● Media is not p2p
Why not???
1 3
2
Signaling
Media jonas@twilio.com
@borjessonjonas

6. Carrier Interop + Media Features
● In our experience:
● Carriers do not in general support re-invites
● Transcoding between carriers
also
● Users...
● wish to record the audio
● use DTMF for controlling the call (hangup-on star)
jonas@twilio.com
@borjessonjonas

7. THE END
jonas@twilio.com
@borjessonjonas