LTE: DL Information Transfer

Direction: E-UTRAN => UE
Signalling Radio Bearer: SRB2 or SRB1
RLC Mode: AM
Logical Channel: DCCH
Transport Channel: DL-SCH

E-UTRAN initiates the DL information transfer procedure whenever there is a need to transfer NAS or non-3GPP dedicated information. E-UTRAN initiates the DL information transfer procedure by sending the DL INFORMATION TRANSFER message

Either SRB2 or SRB1 (only if SRB2 not established yet) is used. If SRB2 is suspended, E-UTRAN does not send this message until SRB2 is resumed

DL INFORMATION TRANSFER procedure is almost similar to DOWNLINK DIRECT TRANSFER procedure in 3G-RNC  

The IE dedicatedInfoType shall carry ‘dedicatedInfoNAS’ or ‘dedicatedInfoCDMA2000-1XRTT ‘(in case of CDMA2000 1XRTT information) or ‘dedicatedInfoCDMA2000-HRPD’ (in case of CDMA2000 HRPD information)

Example1: DL INFORMATION TRANSFER carrying NAS SECURITY MODE COMMAND message












Example2: DL INFORMATION TRANSFER carrying ESM INFORMATION REQUEST message










Reference: 3GPP TS 36.331

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