CS Fallback using Cell Change Order to Geran

NMO I, MO CS Fallback, LAC of Geran cell is same as given in Attach Accept on LTE cell



title CS Fallback to GERAN using CCO

note right of UE: LTE ATTACH

UE->SS: RRC CONNECTION REQUEST

SS->UE: RRC CONNECTION SETUP

UE->SS: RRC CONNECTION SETUP COMPLETE

UE->SS: ATTACH REQUEST

UE->SS: PDN CONNECTIVITY REQUEST

SS->UE: AUTHENTICATION REQUEST

UE->SS: AUTHENTICATION RESPONSE

SS->UE: NAS SECURITY MODE COMMAND

UE->SS: NAS SECURITY MODE COMPLETE

SS->UE: RRC SECURITY MODE COMMAND

UE->SS: RRC SECURITY MODE COMPLETE

SS->UE: UE CAPABILITY ENQUIRY

UE->SS: UE CAPABILITY INFORMATION

SS->UE: ACTIVATE DEFAULT EPS BEARER CONTEXT REQUEST

SS->UE: ATTACH ACCEPT

SS->UE: RRC CONNECTION RECONFIGURATION

UE->SS: RRC CONNECTION RECONFIGURATION COMPLETE

UE->SS: ATTACH COMPLETE

UE->SS: ACTIVATE DEFAULT EPS BEARER CONTEXT ACCEPT

note right of UE: CS Fallback

UE->SS: EXTENDED SERVICE REQUEST

SS->UE: MOBILITY FROM EUTRA COMMAND

UE->SS: CHANNEL REQUEST

SS->UE: IMMEDIATE ASSIGNMENT

UE->SS: CM SERVICE REQUEST

UE->SS: GPRS SUSPENSION REQUEST

SS->UE: CM SERVICE ACCEPT

UE->SS: SETUP

SS->UE: CALL PROCEEDING

SS->UE: ASSIGNMENT COMMAND

UE->SS: ASSIGNMENT COMPLETE

SS->UE: ALERTING

SS->UE: CALL CONNECT

UE->SS: CONNECT ACKNOWLEDGE

UE->SS: DISCONNECT

SS->UE: RELEASE

UE->SS: RELEASE COMPLETE

SS->UE: CHANNEL RELEASE

note right of UE: RAU

UE->SS: EGPRS PACKET CHANNEL REQUEST

SS->UE: IMMEDIATE ASSIGNMENT

UE->SS: ROUTING AREA UPDATE REQUEST

SS->UE: IMMEDIATE ASSIGNMENT

SS->UE: ROUTING AREA UPDATE ACCEPT

UE->SS: EGPRS PACKET CHANNEL REQUEST

SS->UE: IMMEDIATE ASSIGNMENT

UE->SS: PACKET RESOURCE REQUEST

UE->SS: ROUTING AREA UPDATE COMPLETE

SS->UE: PDP Context Activate Indication

UE->SS: PDP Context Activate Response