What is the purpose of the document mentioned?
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To describe the LTE Attach Call Flow.
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What is the purpose of the document mentioned?
To describe the LTE Attach Call Flow.
What does the author welcome from others regarding the document?
Corrections of any mistakes or incorrect data.
What is the purpose of NAS Security Procedure?
To secure the NAS Layer between UE and MME for secure communication.
Who created the LTE attach call flow details?
Avijit Shaw.
What are the procedures MME needs to follow for UE attachment?
What is the purpose of the PDN Connectivity Request in LTE?
To request data and IMS signaling.
What does the RRC Re-Configuration Complete message include?
Activate Default EPS Bearer Context Request Accept Message.
What message does the MME send to initiate NAS Security?
Security Mode Command Message.
How many times does the UE need to send a PDN Connectivity Request?
Two times.
What type of bearer is established for IMS SIP Messages?
Default S1 GTP-U Bearer.
What information does the MME include in the Security Mode Command Message?
KSIASMI, UE Security Capability, IMEISV Req.
What is the purpose of the Create Session Request Message?
To initiate the establishment of S5 Bearer between S-GW and P-GW.
What does the HSS send back to the MME in response to the Location Update?
Update Location Answer message including IMSI, APN, IMEI, MSISDN, PCO, TAI, etc.
What does the UE request from the network in the second PDN Connectivity Request?
The address of P-CSCF for IMS Registration.
What does P-GW send to S-GW after receiving the Credit Control Answer?
Create Session Response.
What does the eNb forward to the MME after receiving the UE's response?
Activate Default EPS Bearer Context Request Accept Message.
What information is included in the Initial UE Message sent to MME?
Attach Request and PDN Connectivity Request (for Data).
What procedure does the MME initiate after completing NAS Security?
Location Update.
What does PCRF provide in response to the CCR?
PCC Rule for the UE in Credit Control Answer (CCA).
What is sent back to P-GW from PCRF after the Credit Control Request?
Credit Control Answer.
What message does the eNb send to the MME to indicate successful sharing of the P-CSCF address?
E-RAB Setup Response.
What is sent by the MME to the HSS during UE Authentication?
An 'Authentication Request' including the User Name, PLMN, etc.
What does the MME verify after receiving the RES from the UE?
Whether XRES is equal to RES.
What initiates the DRB Bearer Establishment?
Initial Context Setup Request message sent by MME to eNb.
What is missing in the described call flow between UE and eNB?
UE Capabilities information sharing.
What completes the LTE Attach procedure?
Establishment of Default EPS Bearer between UE and P-GW.
How does the UE respond after receiving the Authentication Request Message?
Generates the 'RES' value and sends it back to the MME in the 'Authentication Response Message'.
What does the MME send to the HSS during the Location Update?
Location Update message including User Name, IMEI, RAT Type, PLMN, etc.
What does P-GW send to PCRF after receiving the request from S-GW?
Credit Control Request (CCR).
What does the UE send in response to the Security Mode Command Request?
'Security Mode Command Response Message'.
What does UE initiate after the LTE attach procedure?
IMS registration.
What does the MME do after understanding that the UE wants to attach to the network?
Establishes the first bearer for the UE.
What does the UE send in response to the Security Mode Command Message?
Security Mode Command Response Message.
What does the second PDN Connectivity Request in LTE specify?
IMS with QCI - 1.
What does MME send to eNb after receiving the Create Session Response?
E-RAB Setup Request including Activate Default EPS Bearer Context Request.
What message does the UE send in response to the RRC Connection Reconfiguration?
RRC Re-Configuration Complete.
What does the HSS generate in response to the MME's authentication request?
An Authentication Vector (AV) consisting of RAND, AUTH, XRES, and K ASME.
What is initiated by the MME if the authentication is successful?
The NAS Security Procedure.
What message does P-GW send to PCRF in response to the Create Session Request?
Credit Control Request (CCR).
What message does the UE send after establishing the DRB Bearer?
'RRC Connection Reconfiguration Complete' Message.
What message does the eNb send to the UE to activate the default EPS bearer context?
RRC Connection Reconfiguration Message.
What happens after eNB receives the Attach Request Message from UE?
It forwards the message to MME in the Initial UE Message.
What message does the MME send to initiate Session Creation?
Create Session Request Message.
What is the final procedure the MME is ready to initiate after Location Update?
Session Creation Procedure.
What is established between S-GW and P-GW after the Create Session Response?
S5 Bearer.
What is embedded in the 'RRC Connection Reconfiguration' message?
'Attach Accept and Activate Default EPS Bearer Context Request'.
What does the MME do with the XRES value after receiving the AVs from HSS?
Keeps the XRES value and sends the remaining data to the UE in the 'Authentication Request Message'.
What happens if the XRES does not match the RES?
Authentication failure occurs and the attach is rejected.
What does eNb do after receiving the Initial Context Setup Request?
Initiates the DRB Bearer Establishment Procedure.
What message does the UE send to indicate completion of the attach process?
'Attach Complete' Message.
What are the key components of the LTE Attach procedure?
Dowling Synchronization and Uplink Synchronization.
What message does the UE send to initiate the LTE Attach procedure?
Attach Request sent to eNB in RRC Connection Request.
What is established between eNb and S-GW during the LTE attach process?
The S1 Bearer.
What does the first PDN Connectivity Request in LTE specify?
Data with QCI - 9.
What is the first step in the establishment of the Data Radio Bearer (DRB)?
The eNb receives the 'Initial Context Setup Request'.
What is the purpose of the 'Modification Bearer Request'?
To indicate that the S-GW can directly communicate with the eNb for further communication.
What does the Default EPS Bearer Establishment include?
S5 Bearer Establishment, DRB Bearer Establishment, and S1 Bearer Establishment.
What information does the UE include in the Security Mode Command Response Message?
IMEI of the device.
What does S-GW do with the Create Session Request?
Forwards it to P-GW.
What does P-GW do after receiving the PCC Rule?
Installs the Policy Decision for the UE and sends Create Session Response Message to S-GW.
What is indicated by the Security Mode Command Response Message?
That the security algorithms have been completed.
What does the MME send to S-GW to establish a separate bearer for IMS SIP signaling?
Create Session Request.
What does the eNb send after the AS layer is secured?
'RRC Connection Reconfiguration' to the UE.
What message does MME include for the UE in the Initial Context Setup Request?
Attach Accept Message.
What response does the eNb send after receiving the 'RRC Connection Reconfiguration Complete' message?
'Initial Context Setup Response Message' to the MME.
What message does the eNb send to secure the AS Layer?
'Security Mode Command Request Message'.
What does the MME do after receiving the 'Attach Complete' message?
Sends a 'Modification Bearer Request' to the S-GW.
