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Thread: TAU Failure

  1. #1
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    Default TAU Failure

    dear
    please any suggestion to solve the TAU reject from Umts to LTE after Call.


    thanks
    BR
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  3. #2
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    Default Re: TAU Failure

    Hi

    Pls check the TAU Request message value of OLD GUTI.

    Rgds
    Plannerguy

  4. #3
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    Default Re: TAU Failure

    check below snap

    guti.JPG


    Quote Originally Posted by plannerguy View Post
    Hi

    Pls check the TAU Request message value of OLD GUTI.

    Rgds
    Plannerguy

  5. #4
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    Default Re: TAU Failure

    Basically you need to check this:

    3GPP TS 23.003 version 14.3.0 Release 14 21 ETSI TS 123 003 V14.3.0 (2017-05)
    2.8.2.2.2 Mapping in the UE
    When the UE moves from the GERAN/UTRAN to the E-UTRAN, the UE needs to map the RAI and P-TMSI to a
    GUTI to be sent to the MME. The P-TMSI signature is sent intact to the MME.
    The mapping of P-TMSI (TLLI) and RAI in GERAN/UTRAN to GUTI in E-UTRAN shall be performed as follows:
    GERAN/UTRAN <MCC> maps to E-UTRAN <MCC>
    GERAN/UTRAN <MNC> maps to E-UTRAN <MNC>
    GERAN/UTRAN <LAC> maps to E-UTRAN <MME Group ID>
    GERAN/UTRAN <RAC> maps into bit 23 and down to bit 16 of the M-TMSI
    The 8 most significant bits of GERAN/UTRAN <NRI> map to the MME code.
    GERAN/UTRAN <P-TMSI> maps as follows:
    - 6 bits of the GERAN/UTRAN <P-TMSI> starting at bit 29 and down to bit 24 are mapped into bit 29 and
    down to bit 24 of the E-UTRAN <M-TMSI>;
    - 16 bits of the GERAN/UTRAN <P-TMSI> starting at bit 15 and down to bit 0 are mapped into bit 15 and
    down to bit 0 of the E-UTRAN <M-TMSI>.
    The values of <LAC> and <MME group id> shall be disjoint, so that they can be differentiated.
    The most significant bit of the <LAC> shall be set to zero; and the most significant bit of <MME group id> shall be set
    to one. Based on this definition, the most significant bit of the <MME group id> can be used to distinguish the node
    type, i.e. whether it is an MME or SGSN. The UE copies the received old SGSN’s <LAC> into the <MME Group ID>
    when sending a message to an MME, regardless of the value of the most significant bit of the <LAC>.


    Also this one is an important part of your investigation:

    In networks where this definition is not applied (e.g. in networks already configured with LAC with the most significant
    bit set to 1 before LTE deployment), the information in the TAU/RAU request indicating whether the provided
    GUTI/P-TMSI is "native" (i.e. no system change) or "mapped" (i.e. system change) can be used to distinguish the node
    type for UEs implemented according to this release of the specification (see 3GPP TS 24.301 [90] and 3GPP TS 24.008

    [5]). Specific network implementations still satisfying 3GPP standard interfaces can be used for pre-Rel-10 UEs to
    distinguish the node type.
    NOTE 1: As an example, at NAS level, the MME/SGSN can retrieve the old SGSN/MME by using additional
    GUTI/additional RAI/P-TMSI with double DNS query to solve the first time the UE moves between EUTRAN
    and GERAN/UTRAN. As another example, the MME/SGSN can retrieve the old SGSN/MME
    by using double DNS query.

    If you are ok till here check billing strategy.

    B/R
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  6. #5
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    Default Re: TAU Failure

    thanks dear for your support
    Quote Originally Posted by samuraial View Post
    Basically you need to check this:

    3GPP TS 23.003 version 14.3.0 Release 14 21 ETSI TS 123 003 V14.3.0 (2017-05)
    2.8.2.2.2 Mapping in the UE
    When the UE moves from the GERAN/UTRAN to the E-UTRAN, the UE needs to map the RAI and P-TMSI to a
    GUTI to be sent to the MME. The P-TMSI signature is sent intact to the MME.
    The mapping of P-TMSI (TLLI) and RAI in GERAN/UTRAN to GUTI in E-UTRAN shall be performed as follows:
    GERAN/UTRAN <MCC> maps to E-UTRAN <MCC>
    GERAN/UTRAN <MNC> maps to E-UTRAN <MNC>
    GERAN/UTRAN <LAC> maps to E-UTRAN <MME Group ID>
    GERAN/UTRAN <RAC> maps into bit 23 and down to bit 16 of the M-TMSI
    The 8 most significant bits of GERAN/UTRAN <NRI> map to the MME code.
    GERAN/UTRAN <P-TMSI> maps as follows:
    - 6 bits of the GERAN/UTRAN <P-TMSI> starting at bit 29 and down to bit 24 are mapped into bit 29 and
    down to bit 24 of the E-UTRAN <M-TMSI>;
    - 16 bits of the GERAN/UTRAN <P-TMSI> starting at bit 15 and down to bit 0 are mapped into bit 15 and
    down to bit 0 of the E-UTRAN <M-TMSI>.
    The values of <LAC> and <MME group id> shall be disjoint, so that they can be differentiated.
    The most significant bit of the <LAC> shall be set to zero; and the most significant bit of <MME group id> shall be set
    to one. Based on this definition, the most significant bit of the <MME group id> can be used to distinguish the node
    type, i.e. whether it is an MME or SGSN. The UE copies the received old SGSN’s <LAC> into the <MME Group ID>
    when sending a message to an MME, regardless of the value of the most significant bit of the <LAC>.


    Also this one is an important part of your investigation:

    In networks where this definition is not applied (e.g. in networks already configured with LAC with the most significant
    bit set to 1 before LTE deployment), the information in the TAU/RAU request indicating whether the provided
    GUTI/P-TMSI is "native" (i.e. no system change) or "mapped" (i.e. system change) can be used to distinguish the node
    type for UEs implemented according to this release of the specification (see 3GPP TS 24.301 [90] and 3GPP TS 24.008

    [5]). Specific network implementations still satisfying 3GPP standard interfaces can be used for pre-Rel-10 UEs to
    distinguish the node type.
    NOTE 1: As an example, at NAS level, the MME/SGSN can retrieve the old SGSN/MME by using additional
    GUTI/additional RAI/P-TMSI with double DNS query to solve the first time the UE moves between EUTRAN
    and GERAN/UTRAN. As another example, the MME/SGSN can retrieve the old SGSN/MME
    by using double DNS query.

    If you are ok till here check billing strategy.

    B/R

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