Newest course5G Core & E2E Specialist

Cloud-native core, slicing and end-to-end call flow — now live.

Start free · no loginMicro lessons in your browser

Bite-size 5G & 6G lessons with hands-on labs — start learning free, no signup.

Talk to usBring 5G training to your whole org

Bulk seats, SSO / SCORM, co-branded certificates and cohort reporting. Sales-led — we reply within one business day.

4G LTE Essentials

VoLTE call flow (MO to MT)

interactive4 min

Lesson 23 of 33

Card 1 of 714%

Warm-up: Guess before you learn

Try these first, even if you're not sure. Guessing primes your brain.

Two phones support different codecs. What must happen before voice flows?

QoS bearer arrives after the callee answers. What goes wrong?

Should RTP audio packets flow through the SIP control nodes?

Answer all 3to continue — it's OK to be wrong.

All lessons in this level: