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3G UMTS Mobile Terminated Call Flow

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Get a detailed look at a UMTS mobile terminating call. RANAP and RRC signaling in a terminating call is describe in detail.

3G UMTS Mobile Terminating Call Flow

3G UMTS Terminating Call Sequence Diagram

The RANAP message flow presented here was generated with VisualEther from a PCAP file.  The field level details have been preserved for the RANAP messages. Click on a RANAP messages in the sequence diagram to see full field level details. For example clicking on the Paging message reveals field level detail in the message.

ranap Radio Access Network Application Part

  • per.extension_bit 0… …. Extension Bit: False
  • per.choice_index Choice Index: 0
  • ranap.RANAP_PDU RANAP-PDU: initiatingMessage (0)
    • ranap.initiatingMessage initiatingMessage
      • ranap.procedureCode procedureCode: id-Paging (14)
      • per.enum_index Enumerated Index: 1
      • ranap.criticality criticality: ignore (1)
      • per.open_type_length Open Type Length: 21
      • ranap.value value
        • ranap.Paging Paging
          • per.extension_bit 0… …. Extension Bit: False
          • per.optional_field_bit .0.. …. Optional Field Bit: False (protocolExtensions is NOT present)
          • per.sequence_of_length Sequence-Of Length: 2
          • ranap.protocolIEs protocolIEs: 2 items
            • ranap Item 0: id-CN-DomainIndicator
              • ranap.ProtocolIE_Field ProtocolIE-Field
                • ranap.id id: id-CN-DomainIndicator (3)
                • per.enum_index Enumerated Index: 1
                • ranap.criticality criticality: ignore (1)
                • per.open_type_length Open Type Length: 1
                • ranap.value value
                  • per.enum_index Enumerated Index: 0
                  • ranap.CN_DomainIndicator CN-DomainIndicator: cs-domain (0)
            • ranap Item 1: id-PermanentNAS-UE-ID
              • ranap.ProtocolIE_Field ProtocolIE-Field
                • ranap.id id: id-PermanentNAS-UE-ID (23)
                • per.enum_index Enumerated Index: 1
                • ranap.criticality criticality: ignore (1)
                • per.open_type_length Open Type Length: 9
                • ranap.value value
                  • per.extension_bit 0… …. Extension Bit: False
                  • ranap.PermanentNAS_UE_ID PermanentNAS-UE-ID: iMSI (0)
                    • per.octet_string_length Octet String Length: 8
                    • ranap.iMSI iMSI: 21436587000200f0
                    • ranap.imsi_digits IMSI digits: 123456780020000
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One thought on “3G UMTS Mobile Terminated Call Flow

  1. Do you have any info how the iMSI is translated into IMSI digits? As I see this is not a simple hex-to-decimal conversion.

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