Telecom Tutorials by Samir Amberkar

Voice Call continued [Under GSM >> Signaling]    §

Step 6: Call Setup with MS₂, MS₂ is ringing now.

MS2

BTS2

BSC2

MSC2

VLR2

SDCCH, CC - SETUP SDCCH, CC - Call Confirmed RLM (Call Confirmed) DTAP (Call Confirmed) BSSMAP - Assignment Request DCM signaling to determine possible channel RLM (Assignment Command) SDCCH, RR - Assignment Command FACCH, L2 establish1 FACCH, RR - Assignment Complete RLM (Assignment Complete) BSSMAP - Assignment Complete DCM - release SDCCH FACCH, CC - Alert RLM (Alert) DTAP (Alert)

---

MSC1

MSC2

ISUP - ACM

---

MS1

BTS1

BSC1

MSC1

VLR1

DTAP (Alert) RLM (Alert) FACCH, CC - Alert

1: For Layer 2 setup, MS sends SABM frame; BTS acknowledges with UA frame.

We will continue "Voice Call" in next article.

References: GSM Networks book by Heine, GSM book by Mouly and Pautet, Signaling diagrams from 24.007/24.008 (R99).

© Copyright Samir Amberkar 2010

Voice Call - 5 «

GSM Index

» Voice Call - 7