Circuit Switching FallBack (CSFB)

LTE networks fallback to 3G Network circuit switching while calling and sending/receiving SMS because of two reasons:

  • Technical issue
  • Business concern

Path

Routed

  • Stateless (connection-less)
  • Slower
    • Multiple memory access

Switched

  • Stateful (connection-oriented)
  • Faster
    • One memory access

Q & A

  • Q: What construct connectivity?
  • A: Nodes and links