Procedure details

In the sequence diagram, you have the option to filter directly by specific protocol procedures, allowing you to focus on analysis. All procedures are defined using 3GPP definitions.

call-flow-filter-procedures.png

Below, you'll find the list and details of each procedure per protocol. These tables can be used as a reference to understand the procedures list included with the sequence diagram.

Diameter

Diameter is a signaling protocol used in telecommunications for authentication, authorization, and accounting (AAA) purposes. It is often used in communication between network elements, such as between a user's device and a Policy and Charging Rules Function (PCRF) in mobile networks.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

DIAMETER_Cx_ims

I/S-CSCF--HSS

DIAMETER + interface + pdn_class

This interface enables:
•I-CSCF to locate the Serving CSCF for the incoming request
•S-CSCF to obtain the authentication vectors from the HSS
•S-CSCF to obtain the service profile data from the HSS
•S-CSCF to provide the updated registration information to the HSS
•HSS to update the service profile data to the S-CSCF

Cx is a set of procedures that can be executed between the CSCF (interrogating and serving) and the HSS. Commands in this interface are used for the registration, location, and service profile access procedures on these interfaces.

Messages
Name     Code
User-Authorization-Request      300
User-Authorization-Answer     300
Server-Assignment-Request     301
Server-Assignment-Answer     301
Location-Info-Request     302
Location-Info-Answer         302
Multimedia-Auth-Request     303
Multimedia-Auth-Answer      303
Registration-Termination-Request_Cx 304
Registration-Termination-Answer      304
Push-Profile-Request_Cx      305
Push-Profile-Answer_Cx      305

DIAMETER_Gx

PGW--PCRF

DIAMETER + interface + pdn_class

Used by the PCRF to deliver commands for deploying and deleting charging policies to the PDN gateway (P-GW) and used by the P-GW to report bearer events to the PCRF. The Gx interface is located between the Policy and Charging Enforcement Function (PCEF) in PGW and the Policy and Charging Rules Function (PCRF) The Gx interface is used for provisioning and removal of PCC rules from the PCRF to the PCEF in PGW and the transmission of traffic plane events from the PCEF to the PCRF. The Gx interface can be used for charging control, policy control or both by applying AVPs relevant to the application.

The Gx interface provides the following functions:

  • Delivers PCC rules from the PCRF to the PCEF.

  • Deletes PCC rules from the PCEF.

  • Transmits events from the PCEF to the PCRF.

Messages
Name     Code
Re-Auth-Request Gx     258
Re-Auth-Answer Gx     258
Credit-Control-Request Gx     272
Credit-Control-Answer Gx     272

DIAMETER_Gx_data

PGW--PCRF

DIAMETER + interface + pdn_class

Used by the PCRF to deliver commands for deploying and deleting charging policies to the PDN gateway (P-GW) and used by the P-GW to report bearer events to the PCRF, specific to data APN(pdn class). The Gx interface is located between the Policy and Charging Enforcement Function (PCEF) in PGW and the Policy and Charging Rules Function (PCRF) The Gx interface is used for provisioning and removal of PCC rules from the PCRF to the PCEF in PGW and the transmission of traffic plane events from the PCEF to the PCRF. The Gx interface can be used for charging control, policy control or both by applying AVPs relevant to the application.

The Gx interface provides the following functions:

  • Delivers PCC rules from the PCRF to the PCEF.

  • Deletes PCC rules from the PCEF.

  • Transmits events from the PCEF to the PCRF.

Messages
Name     Code
Re-Auth-Request Gx     258
Re-Auth-Answer Gx     258
Credit-Control-Request Gx     272
Credit-Control-Answer Gx     272

DIAMETER_Gx_ims

PGW--PCRF

DIAMETER + interface + pdn_class

Used by the PCRF to deliver commands for deploying and deleting charging policies to the PDN gateway (P-GW) and used by the P-GW to report bearer events to the PCRF, specific to ims apn (pdn class). The Gx interface is located between the Policy and Charging Enforcement Function (PCEF) in PGW and the Policy and Charging Rules Function (PCRF) The Gx interface is used for provisioning and removal of PCC rules from the PCRF to the PCEF in PGW and the transmission of traffic plane events from the PCEF to the PCRF. The Gx interface can be used for charging control, policy control or both by applying AVPs relevant to the application.

The Gx interface provides the following functions:

  • Delivers PCC rules from the PCRF to the PCEF.

  • Deletes PCC rules from the PCEF.

  • Transmits events from the PCEF to the PCRF.

Messages
Name      Code
Re-Auth-Request Gx      258
Re-Auth-Answer Gx     258
Credit-Control-Request Gx     272
Credit-Control-Answer Gx     272

DIAMETER_Gy_data

PGW--OCS

DIAMETER + interface + pdn_class

The Gy interface is used for online charging between the OCS and the PDN Gateway (PGW), this procedure is specific to data APN(pdn class).

Messages
Name      Code
Credit-Control-Request      272
Credit-Control-Answer     272
Abort-Session-Request     274
Abort-Session-Answer     274

DIAMETER_Gy_ims

PGW--OCS

DIAMETER + interface + pdn_class

The Gy interface is used for online charging between the OCS and the PDN Gateway (PGW), this procedure is specific to IMS APN(pdn class).

Messages
Name     Code
Credit-Control-Request     272
Credit-Control-Answer     272
Abort-Session-Request     274
Abort-Session-Answer     274

DIAMETER_Rf_ims

TAS--OFCS

DIAMETER + interface + pdn_class

The Rf reference point is located between the Charging Trigger Function (CTF) and the Offline Charging Data System (OFCS), and is used for the transport of charging events. The Rf interface is between the OCS and the IMS Call Session Control Function (CSCF) , this procedure is specific to IMSAPN(pdn class).

Messages
Name     Code
Accounting-Request Rf     271
Accounting-Answer Rf     271

DIAMETER_Ro_ims

TAS--OCS

DIAMETER + interface + pdn_class

The  Ro interface is between the OCS and the IMS Call Session Control Function (CSCF) , this procedure is specific to IMS APN (pdn class).

Messages
Name     Code
Re-Auth-Request Ro     258
Re-Auth-Answer Ro      258
Credit-Control-Request Ro     272
Credit-Control-Answer Ro     272

DIAMETER_Rx_ims

PCSCF--PCRF

DIAMETER + interface + pdn_class

The Rx reference point is between the Policy and Charging Rules Function (PCRF) and the Call Session Control Function (CSCF), and is used to exchange application level session information between the CSCF application functions. The application function information is part of the input used by the PCRF for the Policy and Charging Control (PCC) decisions, this procedure is specific to IMS APN (pdn class).

Messages
Name     Code
Re-Auth-Request Rx      258
Re-Auth-Answer Rx       258
AA-Request Rx       265
AA-Answer Rx                  265
Abort-Session-Request Rx      274
Abort-Session-Answer Rx     274
Session-Termination-Request Rx     275
Session-Termination-Answer Rx     275

DIAMETER_S6a/S6d

MME--HSS

DIAMETER + interface + pdn_class

The S6a reference point is between the Home Subscriber Server (HSS) and the Mobility Management Entity (MME), and is used for location changes of the MME. The S6d interface is between the HSS and the Serving GPRS Service Node (SGSN), for location changes of the SGSN. The procedures, message parameters and protocol are similar between S6a and S6d.
Reference:  3GPP TS29.272

Messages
Name     Code
Update-Location-Request_S6.    316
Update-Location-Answer_S6.  316
Cancel-Location-Request_S6       317
Cancel-Location-Answer_S6       317
Authentication-Information-Request_S6     318
Authentication-Information-Answer_S6     318
Insert-Subscriber-Data-Request_S6      319
Insert-Subscriber-Data-Answer_S6      319
Delete-Subscriber-Data-Request_S6.    320
Delete-Subscriber-Data-Answer_S6.   320
Purge-UE-Request_S6     321
Purge-UE-Answer_S6.     321
Reset-Request_S6      322
Reset-Answer_S6      322
Notify-Request_S6      323
Notify-Answer_S6       323

DIAMETER_S6b_ims

PGW--AAA

DIAMETER + interface + pdn_class

The S6b reference point is between the PDN Gateway (PGW) and 3GPP AAA server/proxy for mobility related authentication if needed. This reference point may also be used to retrieve and request storage of mobility parameters, and may also be used to retrieve static QoS profile for a UE for non-3GPP access in case dynamic PCC is not supported, this procedure is specific to IMS APN (pdn class).
Reference:  3GPP TS29.273

Messages
Name     Code
Re-Auth-Request-S6b       258
Re-Auth-Answer-S6b       258
AA-Request-S6b-PMIPv6       265
AA-Answer-S6b-PMIPv6       265
Diameter-EAP-Request-S6b-DSMIPv6       268
Diameter-EAP-Answer-S6b-DSMIPv6       268
Abort-Session-Request-S6b-3GPP-AAA-Initiated       274
Abort-Session-Answer-S6b-3GPP-AAA-Initiated       274
Session-Termination-Request-S6b-PGW-Initiated      275
Session-Termination-Answer-S6b-PGW-Initiated       275
Session-Termination-Request-S6b-3GPP-AAA-Initiated.     275
Session-Termination-Answer-S6b-3GPP-AAA-Initiated       275

DIAMETER_Sh_ims

TAS--HSS

DIAMETER + interface + pdn_class

The Sh reference point resides between the Home Subscriber Server (HSS) and an Application Function (AF). The Sh interface implements a Diameter application that allows the download and update of transparent and not-transparent user data, and allows requests and notifications on changes to user data, this procedure is specific to IMS APN (pdn class).
Reference:  3GPP TS29.328/TS29.329

Messages
Name     Code
User-Data-Request       306
User-Data-Answer       306
Profile-Update-Request       307
Profile-Update-Answer       307
Subscribe-Notifications-Request      308
Subscribe-Notifications-Answer       308
Push-Notification-Request        309
Push-Notification-Answer       309

DIAMETER_Sp_ims

PCRF--SPR

DIAMETER + interface + pdn_class

This interface allows the PCRF to request subscription information related to transport level policies from the SPR based on a subscriber ID, a PDN identifier and possible further IP CAN session attributes, as specified in 3GPP TS 23.203 v9.x. This interface allows the SPR to notify the PCRF when the subscription information has been changed if the PCRF has requested such notifications. The SPR shall stop sending the updated subscription information when a cancellation notification request has been received from the PCRF.

PCRF queries the Subscriber Profile Repository(SPR) for dynamic information of subscriber over Sp interface. SPR sends all information about the subscriber policy/quota/rules to PCRF over Sp interface, this procedure is specific to IMS APN (pdn class).

DIAMETER_SWx_ims

HSS--AAA

DIAMETER + interface + pdn_class

The SWx reference point are located between 3GPP AAA Server and HSS and is used for transport of authentication, subscription and PDN connection related data. The SWx interface is used for 3GPP LTE networks, this procedure is specific to IMS APN (pdn class).
Reference:  3GPP TS29.273

Messages
Name     Code
Server-Assignment-Request-SWx       301
Server-Assignment-Answer-SWx      301
Multimedia-Auth-Request SWx       303
Multimedia-Auth-Answer-SWx       303
Registration-Termination-Request-SWx      304
Registration-Termination-Answer-SWx      304
Push-Profile-Request-SWx      305
Push-Profile-Answer-SWx      305

DIAMETER_Sy

PCRF--OCS

DIAMETER + interface + pdn_class

The Sy reference point is located between the Policy and Charging Rules Function (PCRF) and the Online Charging System (OCS). The Sy reference point enables transfer of policy counter status information relating to subscriber spending from the OCS to the PCRF.
Reference:  3GPP TS29.219

Messages
Name     Code
Session-Termination-Request Sy      275
Session-Termination-Answer Sy      275
Spending-Limit-Request       8388635
Spending-Limit-Answer       8388635
Spending-Status-Notification-Request.   8388636
Spending-Status-Notification-Answer.    8388636

GTPv2

GTPv2 (GPRS Tunneling Protocol version 2) is a protocol used in mobile networks, particularly in the packet core network. It facilitates the communication between different network elements, such as between the Serving Gateway (SGW) and the PDN Gateway (PGW) in LTE (Long-Term Evolution) networks.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

GTPv2_Setup_data_apn

MME--SGW--PGW(S11/S5/S8)

GTPv2 + interface + pdn_class

Indicates GTPv2 procedures for data APN-based connections.

The S11 reference point is between the MME and SGW and is used to support mobility and bearer management between the MME and S-GW.
The S5 reference point provides user plane tunneling and tunnel management between the SGW and PGW.
The S8 reference point is the inter-PLMN interface providing the user plane and control plane between the SGW in the Visited PLMN (VPLMN) and the PGW in the Home PLMN (HPLMN).

GTP-U (GPRS Tunnel Protocol User) tunnels are used between two entities of the EPS network. Such tunnels enable the traffic data to be compartmentalized. GTP-U traffic tunnels are constructed on the S1-U, S5 and X2 interfaces. The tunnel is identified by the TEID parameter, the IP addresses and the UDP port numbers. The entity receiving the traffic or signaling data determines the value of the TEID parameter which the sending entity has to use.
The values of the TEID parameter of the GTP-U protocol are exchanged via the GTPv2-C (GPRS Tunnel Protocol Control), S1-AP and X2-AP protocols.

The TEID parameter used for the signaling exchanged over the S5 interface is unique. The same parameter is used for all signaling messages relating to the activation of the various S5 bearers for the different mobiles. The TEID parameter used for the signaling exchanged over S11 interface is unique for each mobile. The same parameter is used for all signaling messages relating to the establishment of the various S1-U bearers for the same mobile.

Bearer Management:

The signaling bearer related to a mobile is created by the CREATE SESSION REQUEST message. It is reinforced by the use of a TEID parameter. The message is transmitted:
– by the MME entity to the serving gateway (SGW), over the S11 interface;
– by the target SGW entity for the PDN gateway (PGW), over the S5 interface. The request is transmitted when any of the following procedures are initiated:

  • attachment of the mobile

  • traffic request from the mobile

  • updating of the tracking area code (TAC)

  • handover

The SGW entity (or respectively PGW entity) responds to the MME entity (or respectively SGW entity) with the CREATE SESSION RESPONSE message.
The signaling bearer is deactivated by the exchange of the DELETE SESSION REQUEST/RESPONSE messages.
The procedure is triggered when the mobile detaches, when the traffic is released, when the TAC changes, leading to a modification of the SGW entity, or when handover occurs, with a switch of the SGW.
The dedicated bearer specific to a mobile is created similarly, modified possibly and deleted by the exchange of the following messages:
– CREATE / MODIFY / DELETE BEARER REQUEST
– CREATE / MODIFY / DELETE BEARER RESPONSE.
The DOWNLINK DATA NOTIFICATION message is sent by the SGW entity to the MME entity, over the S11 interface.
The procedure follows the reception by the SGW entity of data from the PGW entity, with the mobile in ECM-IDLE mode. Just after receiving this message, the MME entity sends the S1-AP PAGING message to the eNB entities belonging to the TAC.

The MME entity may respond with the DOWNLINK DATA NOTIFICATION ACKNOWLEDGE message, indicating whether or not the request is accepted or with the DOWNLINK DATA NOTIFICATION FAILURE INDICATION message if the mobile does not respond to the paging or if the mobile service request is rejected.
The CREATE INDIRECT DATA FORWARDING TUNNEL REQUEST/RESPONSE messages create a specific traffic bearer when handover occurs. This bearer forwards the data traffic received by the source eNB entity to the SGW entity to then be re-transmitted to the mobile via the target eNB entity.

Mobility Management:

Mobility management messages are exchanged between the source and target MME entities, when the handover of the mobile imposes a switch of MME entity.
The source MME entity sends the target MME entity the FORWARD RELOCATION REQUEST message containing the context of the mobile.
The target MME entity responds with the FORWARD RELOCATION RESPONSE message when the resources needed for the handover have been reserved.
The response contains the values of the TEID parameter, which will enable the source SGW entity to redirect the traffic to the target SGW entity during handover.
Upon receiving this message, the source MME entity sends the source eNB entity the command to initiate handover.
The source MME entity sends the target MME entity the FORWARD ACCESS CONTEXT NOTIFICATION message to provide it with the elements of the context of the E-RAB bearer, such as the PDCP sequence number.
The target MME entity sends the source MME entity the FORWARD RELOCATION NOTIFICATION message to indicate that the handover procedure is complete.

The new MME entity sends the CONTEXT REQUEST message to the former one in the procedure of TAI updating, to retrieve information about the context of the mobile.
The former MME entity provides this information in the CONTEXT RESPONSE message, which may contain a positive or negative response.
The new MME entity acknowledges this previous message with the message CONTEXT ACKNOWLEDGE.
Reference:  3GPP TS 29.274-e10 

GTPv2_Setup_ims_apn

MME--SGW--PGW(S11/S5/S8)

GTPv2 + interface + pdn_class

Indicates GTPv2 procedures for IMS APN based connections.

The S11 reference point is between the MME and SGW and is used to support mobility and bearer management between the MME and S-GW.
The S5 reference point provides user plane tunneling and tunnel management between the SGW and PGW.
The S8 reference point is the inter-PLMN interface providing the user plane and control plane between the SGW in the Visited PLMN (VPLMN) and the PGW in the Home PLMN (HPLMN).

GTP-U (GPRS Tunnel Protocol User) tunnels are used between two entities of the EPS network. Such tunnels enable the traffic data to be compartmentalized. GTP-U traffic tunnels are constructed on the S1-U, S5 and X2 interfaces. The tunnel is identified by the TEID parameter, the IP addresses and the UDP port numbers. The entity receiving the traffic or signaling data determines the value of the TEID parameter which the sending entity has to use.
The values of the TEID parameter of the GTP-U protocol are exchanged via the GTPv2-C (GPRS Tunnel Protocol Control), S1-AP and X2-AP protocols.

The TEID parameter used for the signaling exchanged over the S5 interface is unique. The same parameter is used for all signaling messages relating to the activation of the various S5 bearers for the different mobiles. The TEID parameter used for the signaling exchanged over S11 interface is unique for each mobile. The same parameter is used for all signaling messages relating to the establishment of the various S1-U bearers for the same mobile.

Bearer Management:

The signaling bearer related to a mobile is created by the CREATE SESSION REQUEST message. It is reinforced by the use of a TEID parameter. The message is transmitted:
– by the MME entity to the serving gateway (SGW), over the S11 interface;
– by the target SGW entity for the PDN gateway (PGW), over the S5 interface. The request is transmitted when any of the following procedures are initiated:

  • attachment of the mobile

  • traffic request from the mobile

  • updating of the tracking area code (TAC)

  • handover

The SGW entity (or respectively PGW entity) responds to the MME entity (or respectively SGW entity) with the CREATE SESSION RESPONSE message.
The signaling bearer is deactivated by the exchange of the DELETE SESSION REQUEST/RESPONSE messages.
The procedure is triggered when the mobile detaches, when the traffic is released, when the TAC changes, leading to a modification of the SGW entity, or when handover occurs, with a switch of the SGW.
The dedicated bearer specific to a mobile is created similarly, modified possibly and deleted by the exchange of the following messages:
– CREATE / MODIFY / DELETE BEARER REQUEST
– CREATE / MODIFY / DELETE BEARER RESPONSE.
The DOWNLINK DATA NOTIFICATION message is sent by the SGW entity to the MME entity, over the S11 interface.
The procedure follows the reception by the SGW entity of data from the PGW entity, with the mobile in ECM-IDLE mode. Just after receiving this message, the MME entity sends the S1-AP PAGING message to the eNB entities belonging to the TAC.

The MME entity may respond with the DOWNLINK DATA NOTIFICATION ACKNOWLEDGE message, indicating whether or not the request is accepted or with the DOWNLINK DATA NOTIFICATION FAILURE INDICATION message if the mobile does not respond to the paging or if the mobile service request is rejected.
The CREATE INDIRECT DATA FORWARDING TUNNEL REQUEST/RESPONSE messages create a specific traffic bearer when handover occurs. This bearer forwards the data traffic received by the source eNB entity to the SGW entity to then be re-transmitted to the mobile via the target eNB entity.

Mobility Management:

Mobility management messages are exchanged between the source and target MME entities, when the handover of the mobile imposes a switch of MME entity.
The source MME entity sends the target MME entity the FORWARD RELOCATION REQUEST message containing the context of the mobile.
The target MME entity responds with the FORWARD RELOCATION RESPONSE message when the resources needed for the handover have been reserved.
The response contains the values of the TEID parameter, which will enable the source SGW entity to redirect the traffic to the target SGW entity during handover.
Upon receiving this message, the source MME entity sends the source eNB entity the command to initiate handover.
The source MME entity sends the target MME entity the FORWARD ACCESS CONTEXT NOTIFICATION message to provide it with the elements of the context of the E-RAB bearer, such as the PDCP sequence number.
The target MME entity sends the source MME entity the FORWARD RELOCATION NOTIFICATION message to indicate that the handover procedure is complete.

The new MME entity sends the CONTEXT REQUEST message to the former one in the procedure of TAI updating, to retrieve information about the context of the mobile.
The former MME entity provides this information in the CONTEXT RESPONSE message, which may contain a positive or negative response.
The new MME entity acknowledges this previous message with the message CONTEXT ACKNOWLEDGE.
Reference:  3GPP TS 29.274-e10 

GTPv2_Setup_sos_apn

MME--SGW--PGW(S11/S5/S8)

GTPv2 + interface + pdn_class

Indicates GTPv2 procedures for SOS APN based connections which are related with emergency calls.

The S11 reference point is between the MME and SGW and is used to support mobility and bearer management between the MME and S-GW.
The S5 reference point provides user plane tunneling and tunnel management between the SGW and PGW.
The S8 reference point is the inter-PLMN interface providing the user plane and control plane between the SGW in the Visited PLMN (VPLMN) and the PGW in the Home PLMN (HPLMN).

GTP-U (GPRS Tunnel Protocol User) tunnels are used between two entities of the EPS network. Such tunnels enable the traffic data to be compartmentalized. GTP-U traffic tunnels are constructed on the S1-U, S5 and X2 interfaces. The tunnel is identified by the TEID parameter, the IP addresses and the UDP port numbers. The entity receiving the traffic or signaling data determines the value of the TEID parameter which the sending entity has to use.
The values of the TEID parameter of the GTP-U protocol are exchanged via the GTPv2-C (GPRS Tunnel Protocol Control), S1-AP and X2-AP protocols.

The TEID parameter used for the signaling exchanged over the S5 interface is unique. The same parameter is used for all signaling messages relating to the activation of the various S5 bearers for the different mobiles. The TEID parameter used for the signaling exchanged over S11 interface is unique for each mobile. The same parameter is used for all signaling messages relating to the establishment of the various S1-U bearers for the same mobile.

Bearer Management:

The signaling bearer related to a mobile is created by the CREATE SESSION REQUEST message. It is reinforced by the use of a TEID parameter. The message is transmitted:
– by the MME entity to the serving gateway (SGW), over the S11 interface;
– by the target SGW entity for the PDN gateway (PGW), over the S5 interface. The request is transmitted when any of the following procedures are initiated:

  • attachment of the mobile

  • traffic request from the mobile

  • updating of the tracking area code (TAC)

  • handover

The SGW entity (or respectively PGW entity) responds to the MME entity (or respectively SGW entity) with the CREATE SESSION RESPONSE message.
The signaling bearer is deactivated by the exchange of the DELETE SESSION REQUEST/RESPONSE messages.
The procedure is triggered when the mobile detaches, when the traffic is released, when the TAC changes, leading to a modification of the SGW entity, or when handover occurs, with a switch of the SGW.
The dedicated bearer specific to a mobile is created similarly, modified possibly and deleted by the exchange of the following messages:
– CREATE / MODIFY / DELETE BEARER REQUEST
– CREATE / MODIFY / DELETE BEARER RESPONSE.
The DOWNLINK DATA NOTIFICATION message is sent by the SGW entity to the MME entity, over the S11 interface.
The procedure follows the reception by the SGW entity of data from the PGW entity, with the mobile in ECM-IDLE mode. Just after receiving this message, the MME entity sends the S1-AP PAGING message to the eNB entities belonging to the TAC.

The MME entity may respond with the DOWNLINK DATA NOTIFICATION ACKNOWLEDGE message, indicating whether or not the request is accepted or with the DOWNLINK DATA NOTIFICATION FAILURE INDICATION message if the mobile does not respond to the paging or if the mobile service request is rejected.
The CREATE INDIRECT DATA FORWARDING TUNNEL REQUEST/RESPONSE messages create a specific traffic bearer when handover occurs. This bearer forwards the data traffic received by the source eNB entity to the SGW entity to then be re-transmitted to the mobile via the target eNB entity.

Mobility Management:

Mobility management messages are exchanged between the source and target MME entities, when the handover of the mobile imposes a switch of MME entity.
The source MME entity sends the target MME entity the FORWARD RELOCATION REQUEST message containing the context of the mobile.
The target MME entity responds with the FORWARD RELOCATION RESPONSE message when the resources needed for the handover have been reserved.
The response contains the values of the TEID parameter, which will enable the source SGW entity to redirect the traffic to the target SGW entity during handover.
Upon receiving this message, the source MME entity sends the source eNB entity the command to initiate handover.
The source MME entity sends the target MME entity the FORWARD ACCESS CONTEXT NOTIFICATION message to provide it with the elements of the context of the E-RAB bearer, such as the PDCP sequence number.
The target MME entity sends the source MME entity the FORWARD RELOCATION NOTIFICATION message to indicate that the handover procedure is complete.

The new MME entity sends the CONTEXT REQUEST message to the former one in the procedure of TAI updating, to retrieve information about the context of the mobile.
The former MME entity provides this information in the CONTEXT RESPONSE message, which may contain a positive or negative response.
The new MME entity acknowledges this previous message with the message CONTEXT ACKNOWLEDGE.
Reference:  3GPP TS 29.274-e10 

GTPv2_Setup_UNKNOWN_apn

MME--SGW--PGW(S11/S5/S8)

GTPv2 + interface + pdn_class

Indicates GTPv2 procedures where there is no specific APN such as data/IMS/SOS found(unknown).

The S11 reference point is between the MME and SGW and is used to support mobility and bearer management between the MME and S-GW.
The S5 reference point provides user plane tunneling and tunnel management between the SGW and PGW.
The S8 reference point is the inter-PLMN interface providing the user plane and control plane between the SGW in the Visited PLMN (VPLMN) and the PGW in the Home PLMN (HPLMN).

GTP-U (GPRS Tunnel Protocol User) tunnels are used between two entities of the EPS network. Such tunnels enable the traffic data to be compartmentalized. GTP-U traffic tunnels are constructed on the S1-U, S5 and X2 interfaces. The tunnel is identified by the TEID parameter, the IP addresses and the UDP port numbers. The entity receiving the traffic or signaling data determines the value of the TEID parameter which the sending entity has to use.
The values of the TEID parameter of the GTP-U protocol are exchanged via the GTPv2-C (GPRS Tunnel Protocol Control), S1-AP and X2-AP protocols.

The TEID parameter used for the signaling exchanged over the S5 interface is unique. The same parameter is used for all signaling messages relating to the activation of the various S5 bearers for the different mobiles. The TEID parameter used for the signaling exchanged over S11 interface is unique for each mobile. The same parameter is used for all signaling messages relating to the establishment of the various S1-U bearers for the same mobile.

Bearer Management:

The signaling bearer related to a mobile is created by the CREATE SESSION REQUEST message. It is reinforced by the use of a TEID parameter. The message is transmitted:
– by the MME entity to the serving gateway (SGW), over the S11 interface;
– by the target SGW entity for the PDN gateway (PGW), over the S5 interface. The request is transmitted when any of the following procedures are initiated:

  • attachment of the mobile

  • traffic request from the mobile

  • updating of the tracking area code (TAC)

  • handover

The SGW entity (or respectively PGW entity) responds to the MME entity (or respectively SGW entity) with the CREATE SESSION RESPONSE message.
The signaling bearer is deactivated by the exchange of the DELETE SESSION REQUEST/RESPONSE messages.
The procedure is triggered when the mobile detaches, when the traffic is released, when the TAC changes, leading to a modification of the SGW entity, or when handover occurs, with a switch of the SGW.
The dedicated bearer specific to a mobile is created similarly, modified possibly and deleted by the exchange of the following messages:
– CREATE / MODIFY / DELETE BEARER REQUEST
– CREATE / MODIFY / DELETE BEARER RESPONSE
The DOWNLINK DATA NOTIFICATION message is sent by the SGW entity to the MME entity, over the S11 interface.
The procedure follows the reception by the SGW entity of data from the PGW entity, with the mobile in ECM-IDLE mode. Just after receiving this message, the MME entity sends the S1-AP PAGING message to the eNB entities belonging to the TAC.

The MME entity may respond with the DOWNLINK DATA NOTIFICATION ACKNOWLEDGE message, indicating whether or not the request is accepted or with the DOWNLINK DATA NOTIFICATION FAILURE INDICATION message if the mobile does not respond to the paging or if the mobile service request is rejected.
The CREATE INDIRECT DATA FORWARDING TUNNEL REQUEST/RESPONSE messages create a specific traffic bearer when handover occurs. This bearer forwards the data traffic received by the source eNB entity to the SGW entity to then be re-transmitted to the mobile via the target eNB entity.

Mobility Management:

Mobility management messages are exchanged between the source and target MME entities, when the handover of the mobile imposes a switch of MME entity.
The source MME entity sends the target MME entity the FORWARD RELOCATION REQUEST message containing the context of the mobile.
The target MME entity responds with the FORWARD RELOCATION RESPONSE message when the resources needed for the handover have been reserved.
The response contains the values of the TEID parameter, which will enable the source SGW entity to redirect the traffic to the target SGW entity during handover.
Upon receiving this message, the source MME entity sends the source eNB entity the command to initiate handover.
The source MME entity sends the target MME entity the FORWARD ACCESS CONTEXT NOTIFICATION message to provide it with the elements of the context of the E-RAB bearer, such as the PDCP sequence number.
The target MME entity sends the source MME entity the FORWARD RELOCATION NOTIFICATION message to indicate that the handover procedure is complete.

The new MME entity sends the CONTEXT REQUEST message to the former one in the procedure of TAI updating, to retrieve information about the context of the mobile.
The former MME entity provides this information in the CONTEXT RESPONSE message, which may contain a positive or negative response.
The new MME entity acknowledges this previous message with the message CONTEXT ACKNOWLEDGE.
Reference:  3GPP TS 29.274-e10 

HTTP2

HTTP2 is the second major version of the Hypertext Transfer Protocol, used for communication on the World Wide Web. It is designed to improve efficiency and performance by introducing features such as multiplexing and header compression.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

HTTP2_namf

AMF

HTTP2 + interface + dnn

AMF Services and AMF Service Operations. Access and mobility management function (AMF) supports registration, connection, reachability, and mobility management. Provides a channel for exchanging session management messages between a UE and the SMF, and serves as the access point on the control plane of the core network for UEs and (R)AN.

Reference : 3GPP TS 23.502

Namf_Communication

  • UEContextTransfer

  • RegistrationStatusUpdate

  • CreateUEContext

  • ReleaseUEContext

  • N1MessageNotify

  • N2InfoNotify

  • NonUeN2MessageTransfer

Namf_Communication

  • N1N2MessageSubscribe

  • N1N2MessageUnSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_Communication

  • N1N2MessageTransfer

  • N1N2TransferFailureNotification

  • EBIAssignment

  • AMFStatusChangeSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_EventExposure
Namf_Location

  • ProvideLocationInfo

HTTP2_namf_data

AMF

HTTP2 + interface + dnn

AMF Services and AMF Service Operations  with data DNN. Access and mobility management function (AMF) supports registration, connection, reachability, and mobility management. Provides a channel for exchanging session management messages between a UE and the SMF, and serves as the access point on the control plane of the core network for UEs and (R)AN.

Reference : 3GPP TS 23.502

Namf_Communication

  • UEContextTransfer

  • RegistrationStatusUpdate

  • CreateUEContext

  • ReleaseUEContext

  • N1MessageNotify

  • N2InfoNotify

  • NonUeN2MessageTransfer

Namf_Communication

  • N1N2MessageSubscribe

  • N1N2MessageUnSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_Communication

  • N1N2MessageTransfer

  • N1N2TransferFailureNotification

  • EBIAssignment

  • AMFStatusChangeSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_EventExposure
Namf_Location

  • ProvideLocationInfo

HTTP2_namf_ims

AMF

HTTP2 + interface + dnn

AMF Services and AMF Service Operations with IMS DNN. Access and mobility management function (AMF) supports registration, connection, reachability, and mobility management. Provides a channel for exchanging session management messages between a UE and the SMF, and serves as the access point on the control plane of the core network for UEs and (R)AN.

Reference : 3GPP TS 23.502

Namf_Communication

  • UEContextTransfer

  • RegistrationStatusUpdate

  • CreateUEContext

  • ReleaseUEContext

  • N1MessageNotify

  • N2InfoNotify

  • NonUeN2MessageTransfer

Namf_Communication

  • N1N2MessageSubscribe

  • N1N2MessageUnSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_Communication

  • N1N2MessageTransfer

  • N1N2TransferFailureNotification

  • EBIAssignment

  • AMFStatusChangeSubscribe

  • AMFStatusChangeUnSubscribe

  • AMFStatusChangeNotify

Namf_EventExposure
Namf_Location

  • ProvideLocationInfo

HTTP2_nausf

AUSF

HTTP2 + interface + dnn

AUSF Services. Reference : 3GPP TS 23.502
AUSF (Authentication server function) provides UE authentication service to the requester NF. For AKA based authentication, this operation can be also used to recover from synchronization failure situations.

Nausf_UEAuthentication 

HTTP2_nbsf

BSF

HTTP2 + interface + dnn

BSF Services and Service Operations. Reference : 3GPP TS 23.502

Binding Support Function (BSF) offers services to PCFs to register and deregister information about data sessions, and services to other applications to query the BSF which PCF that serves a specific data session. For voice services the Application Function (AF) is the IMS P-CSCF. The concept is not very complicated but is a very important function in order to connect the IMS and the 5GC domains when multiple Network Functions are deployed.

The Nbsf provides the Nbsf_Management_Register, the Nbsf_Management_Deregister and the Nbsf_Management_Discovery services, the Nbsf_Management_Update, the Nbsf_Management_Subscribe, the Nbsf_Management_Unsubscribe and the Nbsf_Management_Notify operations.

HTTP2_nbsf_data

BSF

HTTP2 + interface + dnn

BSF Services and Service Operations related with data DNN. Reference : 3GPP TS 23.502

Binding Support Function (BSF) offers services to PCFs to register and deregister information about data sessions, and services to other applications to query the BSF which PCF that serves a specific data session. For voice services the Application Function (AF) is the IMS P-CSCF. The concept is not very complicated but is a very important function in order to connect the IMS and the 5GC domains when multiple Network Functions are deployed.

The Nbsf provides the Nbsf_Management_Register, the Nbsf_Management_Deregister and the Nbsf_Management_Discovery services, the Nbsf_Management_Update, the Nbsf_Management_Subscribe, the Nbsf_Management_Unsubscribe and the Nbsf_Management_Notify operations.

HTTP2_nbsf_ims

BSF

HTTP2 + interface + dnn

BSF Services and Service Operations related with IMS DNN. Reference : 3GPP TS 23.502

Binding Support Function (BSF) offers services to PCFs to register and deregister information about data sessions, and services to other applications to query the BSF which PCF that serves a specific data session. For voice services the Application Function (AF) is the IMS P-CSCF. The concept is not very complicated but is a very important function in order to connect the IMS and the 5GC domains when multiple Network Functions are deployed.

The Nbsf provides the Nbsf_Management_Register, the Nbsf_Management_Deregister and the Nbsf_Management_Discovery services, the Nbsf_Management_Update, the Nbsf_Management_Subscribe, the Nbsf_Management_Unsubscribe and the Nbsf_Management_Notify operations.

HTTP2_nchf

CHF

HTTP2 + interface + dnn

CHF Services. Reference : 3GPP TS 23.502

Charging support in the 5GC architecture is provided through the Charging Function (CHF), which interacts with PCF and SMF to provide support for charging services. The CHF may authorize access to individual ser- vices or to a group of services by granting credits for authorized traffic. If a user is not authorized to access a certain service, then the CHF may deny credit requests and addi- tionally instruct the SMF to redirect the service request to a specified destination.

The Nchf_SpendingLimitControl service exposed by CHF and consumed by the PCF is specified in 3GPP TS 23.502.

Nchf_SpendingLimitControl_Subscribe : Subscribe to notification of changes in the status of the policy counters available at the CHF and retrieval
of the status of the policy counters for which subscription is accepted by CHF.

Nchf_SpendingLimitControl_Unsubscribe : Cancel the subscription to status changes for all the policy counters available at the CHF.

Nchf_SpendingLimitControl_Notify : Notify the change of the status of the subscribed policy counters available at the CHF. Alternatively, it can be used by the CHF to provide one or more pending statuses for a subscribed policy counter together with the time they have to be applied. Alternatively, it is also used by the CHF to notify the removal of a subscriber from the CHF system, so that the NF consumer can terminate the subscriptions of all the policy counters of the subscriber.

HTTP2_nchf_data

CHF

HTTP2 + interface + dnn

CHF Services with data DNN class. Reference : 3GPP TS 23.502

Charging support in the 5GC architecture is provided through the Charging Function (CHF), which interacts with PCF and SMF to provide support for charging services. The CHF may authorize access to individual ser- vices or to a group of services by granting credits for authorized traffic. If a user is not authorized to access a certain service, then the CHF may deny credit requests and additionally instruct the SMF to redirect the service request to a specified destination.

The Nchf_SpendingLimitControl service exposed by CHF and consumed by the PCF is specified in 3GPP TS 23.502.

Nchf_SpendingLimitControl_Subscribe : Subscribe to notification of changes in the status of the policy counters available at the CHF and retrieval
of the status of the policy counters for which subscription is accepted by CHF.

Nchf_SpendingLimitControl_Unsubscribe : Cancel the subscription to status changes for all the policy counters available at the CHF.

Nchf_SpendingLimitControl_Notify : Notify the change of the status of the subscribed policy counters available at the CHF. Alternatively, it can be used by the CHF to provide one or more pending statuses for a subscribed policy counter together with the time they have to be applied. Alternatively, it is also used by the CHF to notify the removal of a subscriber from the CHF system, so that the NF consumer can terminate the subscriptions of all the policy counters of the subscriber.

HTTP2_nchf_ims

CHF

HTTP2 + interface + dnn

CHF Services with IMS DNN class. Reference : 3GPP TS 23.502

Charging support in the 5GC architecture is provided through the Charging Function (CHF), which interacts with PCF and SMF to provide support for charging services. The CHF may authorize access to individual ser- vices or to a group of services by granting credits for authorized traffic. If a user is not authorized to access a certain service, then the CHF may deny credit requests and additionally instruct the SMF to redirect the service request to a specified destination.

The Nchf_SpendingLimitControl service exposed by CHF and consumed by the PCF is specified in 3GPP TS 23.502.

Nchf_SpendingLimitControl_Subscribe : Subscribe to notification of changes in the status of the policy counters available at the CHF and retrieval
of the status of the policy counters for which subscription is accepted by CHF.

Nchf_SpendingLimitControl_Unsubscribe : Cancel the subscription to status changes for all the policy counters available at the CHF.

Nchf_SpendingLimitControl_Notify : Notify the change of the status of the subscribed policy counters available at the CHF. Alternatively, it can be used by the CHF to provide one or more pending statuses for a subscribed policy counter together with the time they have to be applied. Alternatively, it is also used by the CHF to notify the removal of a subscriber from the CHF system, so that the NF consumer can terminate the subscriptions of all the policy counters of the subscriber.

HTTP2_nnrf

NRF

HTTP2 + interface + dnn

NRF Services and Service Operations. Reference : 3GPP TS 23.502

Network repository function (NRF) Provides a new function for registration and discovery. It enables NFs to discover and communicate with each other through APIs.
When two Network Functions communicate over the 3GPP SBA architecture, they take on two different roles. The Network Function that sends the request has the role of a Service Consumer, while the Network Function that offers a service and triggers some action based on the request has the role of a Service Producer. Upon completion of the requested action, the Service Producer responds back to the Service Consumer. So far so good, but a critical part of this concept is the mechanism for how the Service Consumer can locate and contact a Service Producer that can provide the requested service. The solution is based on the concept of Service Discovery.
Service Discovery relies on that a well-known function in the network keeps track of all available Service Producers and what services they offer. This is achieved through that each Service Producer, for example a 3GPP Network Function like the PCF, registers that its services are available.
In the 5GC architecture, this registration is done to a dedicated Network Function that is called the Network Repository Function (NRF). This concept allows the NRF to keep track of all available services of all Network Functions in the network. It also means that each individual Network Function needs to be provisioned or configured with the address of one or more NRFs, but it does not need, and shall not have, addresses to all other Network Functions configured.

Nnrf_NFManagement service: This service enables one NF to manage its NF profile in NRF (i.e. register, update, deregister). This service also allows a consumer NF or SCP to subscribe in NRF to receive notifications regarding changes in the NF profile of other NFs.

Nnrf_NFDiscovery service: This service enables one NF or SCP to discover a set of NF instances with specific NF service or a target NF type or one or more SCPs. The service also enables one NF service or SCP to discover a specific NF service. The service operations defined below allow the NF/NF services or SCP to communicate with NRF.
This service also enables an SCP to discover SCPs.

Nnrf_AccessToken_service: This service provides OAuth2 2.0 Access Tokens for NF to NF authorization as defined in TS 33.501 [15].

Nnrf_Bootstrapping service: The Nnrf_Bootstrapping service lets NF Service Consumers of the NRF know about the services endpoints it supports, the NRF Instance ID and NRF Set ID if the NRF is part of an NRF set, by using a version- independent URI endpoint that does not need to be discovered by using a Discovery service

HTTP2_nnrf_data

NRF

HTTP2 + interface + dnn

NRF Services and Service Operations with data DNN class. Reference : 3GPP TS 23.502
Network repository function (NRF) Provides a new function for registration and discovery. It enables NFs to discover and communicate with each other through APIs.
When two Network Functions communicate over the 3GPP SBA architecture, they take on two different roles. The Network Function that sends the request has the role of a Service Consumer, while the Network Function that offers a service and triggers some action based on the request has the role of a Service Producer. Upon completion of the requested action, the Service Producer responds back to the Service Consumer. So far so good, but a critical part of this concept is the mechanism for how the Service Consumer can locate and contact a Service Producer that can provide the requested service. The solution is based on the concept of Service Discovery.
Service Discovery relies on that a well-known function in the network keeps track of all available Service Producers and what services they offer. This is achieved through that each Service Producer, for example a 3GPP Network Function like the PCF, registers that its services are available.
In the 5GC architecture, this registration is done to a dedicated Network Function that is called the Network Repository Function (NRF). This concept allows the NRF to keep track of all available services of all Network Functions in the network. It also means that each individual Network Function needs to be provi- sioned or configured with the address of one or more NRFs, but it does not need, and shall not have, addresses to all other Network Functions configured.

Nnrf_NFManagement service: This service enables one NF to manage its NF profile in NRF (i.e. register, update, deregister). This service also allows a consumer NF or SCP to subscribe in NRF to receive notifications regarding changes in the NF profile of other NFs.

Nnrf_NFDiscovery service: This service enables one NF or SCP to discover a set of NF instances with specific NF service or a target NF type or one or more SCPs. The service also enables one NF service or SCP to discover a specific NF service. The service operations defined below allow the NF/NF services or SCP to communicate with NRF.
This service also enables an SCP to discover SCPs.

Nnrf_AccessToken_service: This service provides OAuth2 2.0 Access Tokens for NF to NF authorization as defined in TS 33.501 [15].

Nnrf_Bootstrapping service: The Nnrf_Bootstrapping service lets NF Service Consumers of the NRF know about the services endpoints it supports, the NRF Instance ID and NRF Set ID if the NRF is part of an NRF set, by using a version- independent URI endpoint that does not need to be discovered by using a Discovery service

HTTP2_nnrf_ims

NRF

HTTP2 + interface + dnn

NRF Services and Service Operations with ims dnn class. Reference : 3GPP TS 23.502
Network repository function (NRF) Provides a new function for registration and discovery. It enables NFs to discover and communicate with each other through APIs.
When two Network Functions communicate over the 3GPP SBA architecture, they take on two different roles. The Network Function that sends the request has the role of a Service Consumer, while the Network Function that offers a service and triggers some action based on the request has the role of a Service Producer. Upon completion of the requested action, the Service Producer responds back to the Service Consumer. So far so good, but a critical part of this concept is the mechanism for how the Service Consumer can locate and contact a Service Producer that can provide the requested service. The solution is based on the concept of Service Discovery.
Service Discovery relies on that a well-known function in the network keeps track of all available Service Producers and what services they offer. This is achieved through that each Service Producer, for example a 3GPP Network Function like the PCF, registers that its services are available.
In the 5GC architecture, this registration is done to a dedicated Network Function that is called the Network Repository Function (NRF). This concept allows the NRF to keep track of all available services of all Network Functions in the network. It also means that each individual Network Function needs to be provi- sioned or configured with the address of one or more NRFs, but it does not need, and shall not have, addresses to all other Network Functions configured.

Nnrf_NFManagement service: This service enables one NF to manage its NF profile in NRF (i.e. register, update, deregister). This service also allows a consumer NF or SCP to subscribe in NRF to receive notifications regarding changes in the NF profile of other NFs.

Nnrf_NFDiscovery service: This service enables one NF or SCP to discover a set of NF instances with specific NF service or a target NF type or one or more SCPs. The service also enables one NF service or SCP to discover a specific NF service. The service operations defined below allow the NF/NF services or SCP to communicate with NRF.
This service also enables an SCP to discover SCPs.

Nnrf_AccessToken_service: This service provides OAuth2 2.0 Access Tokens for NF to NF authorization as defined in TS 33.501 [15].

Nnrf_Bootstrapping service: The Nnrf_Bootstrapping service lets NF Service Consumers of the NRF know about the services endpoints it supports, the NRF Instance ID and NRF Set ID if the NRF is part of an NRF set, by using a version- independent URI endpoint that does not need to be discovered by using a Discovery service

HTTP2_npcf

PCF

HTTP2 + interface + dnn

PCF Services. Policy control function (PCF) Provides a unified policy framework and policy rules for control plane functions.

Reference : 3GPP TS 23.502

Npcf_AMPolicyControl service: NF Service Consumer, e.g. AMF, can create and manage an AM Policy Association in the PCF through which the NF Service Consumer receives access and mobility related policy information for a UE identified by a SUPI.

Npcf_SMPolicyControl service: NF Service Consumer, e.g. SMF, can create and manage a SM Policy Association in the PCF through which the NF Service Consumer receives policy information for a PDU Session.
As part of this service, the PCF may provide the NF Service Consumer, e.g. SMF, with policy information for the PDU Session that may contain:

  • PDU Session related policy information as defined in clause 6.4 of TS 23.503 [20]

  • PCC rule information as defined in clause 6.3 of TS 23.503 [20]

  • Policy Control Request Trigger information i.e. a set of Policy Control Request Trigger(s) as defined in clause 6.1.3.5 of TS 23.503 [20]

Npcf_PolicyAuthorization Service: This service is to authorise an AF request and to create policies as requested by the authorized AF for the PDU Session to which the AF session is bound. Additionally, this service allows an AF or TSCTSF to exchange port management information with DS-TT and NW-TT. This service allows the NF consumer to subscribe/unsubscribe the notification of events, which are defined in clause 6.1.3.18 of TS 23.503 [20].

Npcf_BDTPolicyControl Service: This service provides background data transfer policy, which includes the following functionalities:

  • Get background data transfer policies based on the request via NEF from AF; and

  • Update background data transfer based on the selection provided by AF.

Npcf_UEPolicyControl Service: NF Service Consumer, e.g. AMF, may create and manage a UE Policy Association in the PCF through which the NF Service Consumer receives Policy Control Request Trigger of UE Policy Association.

Npcf_EventExposure service: This service enables an NF to subscribe and get notified about PCF events for a group of UE(s) or any UE accessing a combination of (DNN, S-NSSAI).
The events can be subscribed by a NF consumer are described in clause 6.1.3.18 of TS 23.503 [20].

Npcf_AMPolicyAuthorization Service: This service is to authorise an AF request and potentially create or change access and mobility management policies of a UE based on the request of the authorized AF or TSCTSF. This service allows the NF consumer to subscribe/unsubscribe the notification of events for related to a user (i.e. a SUPI) that has an AM or UE Policy Association established, or both, the list of events are defined in clause 6.1.3.18 of TS 23.503 [20].

HTTP2_npcf_data

PCF

HTTP2 + interface + dnn

PCF Services with data DNN. Policy control function (PCF) Provides a unified policy framework and policy rules for control plane functions.

Reference : 3GPP TS 23.502

Npcf_AMPolicyControl service: NF Service Consumer, e.g. AMF, can create and manage an AM Policy Association in the PCF through which the NF Service Consumer receives access and mobility related policy information for a UE identified by a SUPI.

Npcf_SMPolicyControl service: NF Service Consumer, e.g. SMF, can create and manage a SM Policy Association in the PCF through which the NF Service Consumer receives policy information for a PDU Session.
As part of this service, the PCF may provide the NF Service Consumer, e.g. SMF, with policy information for the PDU Session that may contain:

  • PDU Session related policy information as defined in clause 6.4 of TS 23.503 [20].

  • PCC rule information as defined in clause 6.3 of TS 23.503 [20].

  • Policy Control Request Trigger information i.e. a set of Policy Control Request Trigger(s) as defined in clause 6.1.3.5 of TS 23.503 [20].

Npcf_PolicyAuthorization Service: This service is to authorize an AF request and to create policies as requested by the authorized AF for the PDU Session to which the AF session is bound. Additionally, this service allows an AF or TSCTSF to exchange port management information with DS-TT and NW-TT. This service allows the NF consumer to subscribe/unsubscribe the notification of events, which are defined in clause 6.1.3.18 of TS 23.503 [20].

Npcf_BDTPolicyControl Service: This service provides background data transfer policy, which includes the following functionalities:

  • Get background data transfer policies based on the request via NEF from AF; and

  • Update background data transfer based on the selection provided by AF.

Npcf_UEPolicyControl Service: NF Service Consumer, e.g. AMF, may create and manage a UE Policy Association in the PCF through which the NF Service Consumer receives Policy Control Request Trigger of UE Policy Association.

Npcf_EventExposure service: This service enables an NF to subscribe and get notified about PCF events for a group of UE(s) or any UE accessing a combination of (DNN, S-NSSAI).
The events can be subscribed by a NF consumer are described in clause 6.1.3.18 of TS 23.503 [20].

Npcf_AMPolicyAuthorization Service: This service is to authorize an AF request and potentially create or change access and mobility management policies of a UE based on the request of the authorized AF or TSCTSF. This service allows the NF consumer to subscribe/unsubscribe the notification of events for related to a user (i.e. a SUPI) that has an AM or UE Policy Association established, or both, the list of events are defined in clause 6.1.3.18 of TS 23.503 [20].

HTTP2_npcf_ims

PCF

HTTP2 + interface + dnn

PCF Services with IMS DNN. Policy control function (PCF) Provides a unified policy framework and policy rules for control plane functions.

Reference : 3GPP TS 23.502

Npcf_AMPolicyControl service: NF Service Consumer, e.g. AMF, can create and manage an AM Policy Association in the PCF through which the NF Service Consumer receives access and mobility related policy information for a UE identified by a SUPI.

Npcf_SMPolicyControl service: NF Service Consumer, e.g. SMF, can create and manage a SM Policy Association in the PCF through which the NF Service Consumer receives policy information for a PDU Session.
As part of this service, the PCF may provide the NF Service Consumer, e.g. SMF, with policy information for the PDU Session that may contain:

  • PDU Session related policy information as defined in clause 6.4 of TS 23.503 [20].

  • PCC rule information as defined in clause 6.3 of TS 23.503 [20].

  • Policy Control Request Trigger information i.e. a set of Policy Control Request Trigger(s) as defined in clause 6.1.3.5 of TS 23.503 [20].

Npcf_PolicyAuthorization service: This service is to authorize an AF request and to create policies as requested by the authorized AF for the PDU Session to which the AF session is bound. Additionally, this service allows an AF or TSCTSF to exchange port management information with DS-TT and NW-TT. This service allows the NF consumer to subscribe/unsubscribe the notification of events, which are defined in clause 6.1.3.18 of TS 23.503 [20].

Npcf_BDTPolicyControl service: This service provides background data transfer policy, which includes the following functionalities:

  • Get background data transfer policies based on the request via NEF from AF; and

  • Update background data transfer based on the selection provided by AF.

Npcf_UEPolicyControl service: NF Service Consumer, e.g. AMF, may create and manage a UE Policy Association in the PCF through which the NF Service Consumer receives Policy Control Request Trigger of UE Policy Association.

Npcf_EventExposure service: This service enables an NF to subscribe and get notified about PCF events for a group of UE(s) or any UE accessing a combination of (DNN, S-NSSAI).
The events can be subscribed by a NF consumer are described in clause 6.1.3.18 of TS 23.503 [20].

Npcf_AMPolicyAuthorization service: This service is to authorize an AF request and potentially create or change access and mobility management policies of a UE based on the request of the authorized AF or TSCTSF. This service allows the NF consumer to subscribe/unsubscribe the notification of events for related to a user (i.e. a SUPI) that has an AM or UE Policy Association established, or both, the list of events are defined in clause 6.1.3.18 of TS 23.503 [20].

HTTP2_nsmf_data

SMF

HTTP2 + interface + dnn

SMF Services and SMF Service Operations with data DNN. Session management function (SMF) provides the session management, tunnel maintenance, IP address allocation and management, UP function selection, policy enforcement, QoS control, charging data collection, roaming, and other functions.

Reference : 3GPP TS 23.502

Nsmf_PDUSession service: This service operates on the PDU Sessions. The following are the key functionalities of this NF service:

  • (between AMF and SMF) Creation / Deletion / Modification of AMF-SMF interactions for PDU Sessions

  • The resource handled between AMF and SMF via Create / Update / Release SM context operations corresponds to the AMF-SMF association for a PDU Session

  • When the AMF has got no association with an SMF to support a PDU Session, the AMF creates such association via the Nsmf_PDUSession_CreateSMContext operation. The context created is identified via the SM Context ID. Otherwise (e.g. at hand-over between 3GPP and Non 3GPP access) the AMF uses the Nsmf_PDUSession_UpdateSMContext operation

Nsmf_PDUSession_Create service operation: Create a new PDU Session in the H-SMF or SMF or create an association with an existing PDN
connection in the home SMF+PGW-C.

Nsmf_PDUSession_Update service operation: Update the established PDU Session.
This service operation is invoked by the V-SMF towards the H-SMF in the case of UE or serving network requested PDU Session Modification in order for the V-SMF to transfer the PDU Session Modification request. It can also be invoked by the V-SMF to indicate to the H-SMF that the access type of the PDU session can be changed.

Nsmf_PDUSession_Release service operation: It causes the immediate and unconditional deletion of the resources associated with the PDU Session. This service operation is used by V-SMF to request the H-SMF or used by I-SMF to request the SMF to release the resources related to a PDU Session for the serving network initiated PDU release case (e.g. implicit De-registration of UE in the serving network).

Nsmf_PDUSession_CreateSMContext service operation: It creates an AMF-SMF association to support a PDU Session.

Nsmf_PDUSession_UpdateSMContext service operation: It allows to update the AMF-SMF association to support a PDU Session and/or to provide SMF with N1/N2 SM information received from the UE or from the AN, or allows to establish forwarding tunnel between UPFs controlled by different SMFs (e.g. by UPF controlled by old I-SMF and UPF controlled by new I-SMF).

Nsmf_PDUSession_ReleaseSMContext service operation: It allows to release the AMF-SMF association for a certain PDU Session because the PDU Session has been released.

Nsmf_PDUSession_SMContextStatusNotify service operation: This service operation is used by the SMF to notify its consumers about the status of an SM context related to a PDU Session (e.g. PDU Session Release due to local reasons within the SMF, PDU Session handover to a different system or access type, SMF context transfer, triggering I-SMF selection for the PDU Session). The SMF may use this service operation to update the SMF derived CN assisted RAN parameters tuning in the AMF. The SMF may report the DDN Failure with NEF Correlation ID to the AMF.

Nsmf_PDUSession_StatusNotify service operation: This service operation is used by the SMF to notify its consumers about the status of a PDU Session (e.g. PDU Session is released due to local reasons within the H-SMF, PDU Session handover to a different system or access type, triggering I-SMF reselection for the PDU Session).

Nsmf_PDUSession_ContextPush service operation: This service operation is used by the SMF as Service Consumer to push one SM Context to a another SMF as NF Service Producer. It may be triggered by OAM.

Nsmf_PDUSession_SendMOData service operation: When the AMF has received MO Small Data from the UE in NAS procedure, this service operation allows the AMF to send the MO Small Data to the SMF.

Nsmf_PDUSession_TransferMOData service operation: When the V-SMF/I-SMF has received MO Small Data from AMF, this service operation allows the V-SMF/I-SMF to forward the MO Small Data to the (H-)SMF.

Nsmf_PDUSession_TransferMTData service operation: When the (H-)SMF has received MT Small Data from the NEF, this service operation allows the (H- )SMF to send the MT Small Data to the V-SMF/I-SMF.

Nsmf_EventExposure Service: This service provides events related to PDU Sessions towards consumer NF. The service operations exposed by this service allow other NFs to subscribe and get notified of events happening on PDU Sessions. The following are the key functionalities of this NF service.

  • Allow consumer NFs to Subscribe and unsubscribe for an Event ID on PDU Session(s)

  • Allow the NWDAF to collect data for network data analytics as specified in TS 23.288 [50]

  • Notifying events on the PDU Session to the subscribed NFs

  • Allow consumer NFs to acknowledge or respond to an event notification

Nsmf_EventExposure_Notify service operation: Report UE PDU Session related event(s) to the NF which has subscribed to the event report service.

Nsmf_EventExposure_AppRelocationInfo service operation: Acknowledge the notification from the SMF regarding UE PDU Session related event(s).

Nsmf_EventExposure_Subscribe service operation: This service operation is used by an NF to subscribe or modify a subscription for event notifications on a specified PDU Session or for all PDU Sessions of one UE, group of UE(s) or any UE.

Nsmf_EventExposure_UnSubscribe service operation: This service operation is used by an NF to unsubscribe event notifications.

Nsmf_PDUSession_ContextRequest service operation: This service operation is used by the NF Consumer to request for SM Context (e.g. during EPS IWK, HO, SM Context transfer indication), or during mobility procedure with I-SMF (or V-SMF) changes or may be triggered by OAM.

HTTP2_nsmf_ims

SMF

HTTP2 + interface + dnn

SMF Services and SMF Service Operations with IMS DNN. Session management function (SMF) provides the session management, tunnel maintenance, IP address allocation and management, UP function selection, policy enforcement, QoS control, charging data collection, roaming, and other functions.

Reference : 3GPP TS 23.502

Nsmf_PDUSession service: This service operates on the PDU Sessions. The following are the key functionalities of this NF service:

  • (between AMF and SMF) Creation / Deletion / Modification of AMF-SMF interactions for PDU Sessions

  • The resource handled between AMF and SMF via Create / Update / Release SM context operations corresponds to the AMF-SMF association for a PDU Session

  • When the AMF has got no association with an SMF to support a PDU Session, the AMF creates such association via the Nsmf_PDUSession_CreateSMContext operation. The context created is identified via the SM Context ID. Otherwise (e.g. at hand-over between 3GPP and Non 3GPP access) the AMF uses the Nsmf_PDUSession_UpdateSMContext operation

Nsmf_PDUSession_Create service operation: Create a new PDU Session in the H-SMF or SMF or create an association with an existing PDN
connection in the home SMF+PGW-C.

Nsmf_PDUSession_Update service operation: Update the established PDU Session.
This service operation is invoked by the V-SMF towards the H-SMF in the case of UE or serving network requested PDU Session Modification in order for the V-SMF to transfer the PDU Session Modification request. It can also be invoked by the V-SMF to indicate to the H-SMF that the access type of the PDU session can be changed.

Nsmf_PDUSession_Release service operation: It causes the immediate and unconditional deletion of the resources associated with the PDU Session. This service operation is used by V-SMF to request the H-SMF or used by I-SMF to request the SMF to release the resources related to a PDU Session for the serving network initiated PDU release case (e.g. implicit De-registration of UE in the serving network).

Nsmf_PDUSession_CreateSMContext service operation: It creates an AMF-SMF association to support a PDU Session.

Nsmf_PDUSession_UpdateSMContext service operation: It allows to update the AMF-SMF association to support a PDU Session and/or to provide SMF with N1/N2 SM information received from the UE or from the AN, or allows to establish forwarding tunnel between UPFs controlled by different SMFs (e.g. by UPF controlled by old I-SMF and UPF controlled by new I-SMF).

Nsmf_PDUSession_ReleaseSMContext service operation: It allows to release the AMF-SMF association for a certain PDU Session because the PDU Session has been released.

Nsmf_PDUSession_SMContextStatusNotify service operation: This service operation is used by the SMF to notify its consumers about the status of an SM context related to a PDU Session (e.g. PDU Session Release due to local reasons within the SMF, PDU Session handover to a different system or access type, SMF context transfer, triggering I-SMF selection for the PDU Session). The SMF may use this service operation to update the SMF derived CN assisted RAN parameters tuning in the AMF. The SMF may report the DDN Failure with NEF Correlation ID to the AMF.

Nsmf_PDUSession_StatusNotify service operation: This service operation is used by the SMF to notify its consumers about the status of a PDU Session (e.g. PDU Session is released due to local reasons within the H-SMF, PDU Session handover to a different system or access type, triggering I-SMF reselection for the PDU Session).

Nsmf_PDUSession_ContextPush service operation: This service operation is used by the SMF as Service Consumer to push one SM Context to a another SMF as NF Service Producer. It may be triggered by OAM.

Nsmf_PDUSession_SendMOData service operation: When the AMF has received MO Small Data from the UE in NAS procedure, this service operation allows the AMF to send the MO Small Data to the SMF.

Nsmf_PDUSession_TransferMOData service operation: When the V-SMF/I-SMF has received MO Small Data from AMF, this service operation allows the V-SMF/I-SMF to forward the MO Small Data to the (H-)SMF.

Nsmf_PDUSession_TransferMTData service operation: When the (H-)SMF has received MT Small Data from the NEF, this service operation allows the (H- )SMF to send the MT Small Data to the V-SMF/I-SMF.

Nsmf_EventExposure service: This service provides events related to PDU Sessions towards consumer NF. The service operations exposed by this service allow other NFs to subscribe and get notified of events happening on PDU Sessions. The following are the key functionalities of this NF service.

  • Allow consumer NFs to Subscribe and unsubscribe for an Event ID on PDU Session(s)

  • Allow the NWDAF to collect data for network data analytics as specified in TS 23.288 [50]

  • Notifying events on the PDU Session to the subscribed NFs

  • Allow consumer NFs to acknowledge or respond to an event notification

Nsmf_EventExposure_Notify service operation: Report UE PDU Session related event(s) to the NF which has subscribed to the event report service.

Nsmf_EventExposure_AppRelocationInfo service operation: Acknowledge the notification from the SMF regarding UE PDU Session related event(s).

Nsmf_EventExposure_Subscribe service operation: This service operation is used by an NF to subscribe or modify a subscription for event notifications on a specified PDU Session or for all PDU Sessions of one UE, group of UE(s) or any UE.

Nsmf_EventExposure_UnSubscribe service operation: This service operation is used by an NF to unsubscribe event notifications.

Nsmf_PDUSession_ContextRequest service operation: This service operation is used by the NF Consumer to request for SM Context (e.g. during EPS IWK, HO, SM Context transfer indication), or during mobility procedure with I-SMF (or V-SMF) changes or may be triggered by OAM.

HTTP2_nsmsf

SMF

HTTP2 + interface + dnn

SMSF Services. The SMSF(Short Message Service Function) is an optional Network Function that is only deployed for enabling SMS over NAS services. Just as other Control Plane network functions in the 5G architecture, the SMSF exposes a service-based interface relying on HTTP communication, called Nsmsf. It connects with the AMF and the UDM Network Functions within the 5G Core architecture. The SMSF checks subscription data through interacting with the UDM, generates charging records and forwards SMS messages between the AMF and the SMS networks external to the 5G Core architecture.

 Reference : 3GPP TS 23.502

This service allows AMF to authorize SMS and activate SMS for the served user on SMSF. This service allows downlink SMS message transmit from consumer NF to SMSF.

HTTP2_nudm

UDM

HTTP2 + interface + dnn

UDM Services and Service Operations. Unified data management (UDM) Provides unified data management, 3GPP AKA authentication, user identification, access authorization, registration, mobility, subscription, and SMS management.

Reference : 3GPP TS 23.502

Nudm_SubscriberDataManagement (SDM) service: Subscription data types used in the Nudm_SubscriberDataManagement service are:

  • Access and Mobility Subscription data (data needed for UE Registration and Mobility Management)

  • Slice Selection Subscription data (data needed for Slice Selection

  • SMF Selection Subscription data (data needed for SMF Selection)

  • UE context in SMF data

  • SMS Management Subscription data (data needed by SMSF for SMSF Registration)

  • SMS Subscription data (data needed in AMF)

  • Session Management Subscription data (data needed for PDU Session Establishment)

  • Identifier translation (Corresponding SUPI / MSISDN for input GPSI.)

  • Intersystem continuity Context

  • LCS privacy (data needed by GMLC)

  • LCS mobile origination (data needed by AMF)

  • User consent for UE data collection

  • UE reachability

  • V2X Subscription data

  • ProSe Subscription data

  • MBS Subscription data

Nudm_UEAuthentication Service  : This service is used by the requester NF to get authentication data and provide UDM with the result of the authentication procedure success. In the case of SNPN, this service may be used to instruct the AUSF to execute authentication towards AAA-S.

Nudm_EventExposure service : The NF consumer subscribes to receive an event, deletes the subscription of an event if already defined in UDM, UDM reports the event to the consumer that has previously subscribed or The NF consumer requests to modify an existing subscription to event notifications.

Nudm_ParameterProvision service : This service is for allowing NEF to provision of information which can be used for the UE in 5GS.

Nudm_NIDDAuthorisation service :  The consumer requests authorisation for NIDD Configuration or is used for the UDM to notify the NIDD Authorization Update to NF consumer.

Nudm_ServiceSpecificAuthorisation service : This service is for authorisation of a specific service configuration.

Nudm_ReportSMDeliveryStatus service : This service is to report the SM-Delivery Status to UDM.

HTTP2_nudm_data

UDM

HTTP2 + interface + dnn

UDM Services and Service Operations with data DNN class. Unified data management (UDM) Provides unified data management, 3GPP AKA authentication, user identification, access authorization, registration, mobility, subscription, and SMS management.

Reference : 3GPP TS 23.502

Nudm_SubscriberDataManagement (SDM) Service : Subscription data types used in the Nudm_SubscriberDataManagement Service are :

  • Access and Mobility Subscription data (data needed for UE Registration and Mobility Management)

  • Slice Selection Subscription data (data needed for Slice Selection

  • SMF Selection Subscription data (data needed for SMF Selection)

  • UE context in SMF data

  • SMS Management Subscription data (data needed by SMSF for SMSF Registration)

  • SMS Subscription data (data needed in AMF)

  • Session Management Subscription data (data needed for PDU Session Establishment)

  • Identifier translation (Corresponding SUPI / MSISDN for input GPSI.)

  • Intersystem continuity Context

  • LCS privacy (data needed by GMLC)

  • LCS mobile origination (data needed by AMF)

  • User consent for UE data collection

  • UE reachability

  • V2X Subscription data

  • ProSe Subscription data

  • MBS Subscription data

Nudm_UEAuthentication Service  : This service is used by the requester NF to get authentication data and provide UDM with the result of the authentication procedure success. In the case of SNPN, this service may be used to instruct the AUSF to execute authentication towards AAA-S.

Nudm_EventExposure service : The NF consumer subscribes to receive an event, deletes the subscription of an event if already defined in UDM, UDM reports the event to the consumer that has previously subscribed or The NF consumer requests to modify an existing subscription to event notifications.

Nudm_ParameterProvision service : This service is for allowing NEF to provision of information which can be used for the UE in 5GS.

Nudm_NIDDAuthorisation service :  The consumer requests authorisation for NIDD Configuration or is used for the UDM to notify the NIDD Authorization Update to NF consumer.

Nudm_ServiceSpecificAuthorisation service : This service is for authorisation of a specific service configuration.

Nudm_ReportSMDeliveryStatus service : This service is to report the SM-Delivery Status to UDM.

HTTP2_nudm_ims

UDM

HTTP2 + interface + dnn

UDM Services and Service Operations with IMS DNN class. Unified data management (UDM) Provides unified data management, 3GPP AKA authentication, user identification, access authorization, registration, mobility, subscription, and SMS management.

Reference : 3GPP TS 23.502

Nudm_SubscriberDataManagement (SDM) Service : Subscription data types used in the Nudm_SubscriberDataManagement Service are:

  • Access and Mobility Subscription data (data needed for UE Registration and Mobility Management)

  • Slice Selection Subscription data (data needed for Slice Selection

  • SMF Selection Subscription data (data needed for SMF Selection)

  • UE context in SMF data

  • SMS Management Subscription data (data needed by SMSF for SMSF Registration)

  • SMS Subscription data (data needed in AMF)

  • Session Management Subscription data (data needed for PDU Session Establishment)

  • Identifier translation (Corresponding SUPI / MSISDN for input GPSI.)

  • Intersystem continuity Context

  • LCS privacy (data needed by GMLC)

  • LCS mobile origination (data needed by AMF)

  • User consent for UE data collection

  • UE reachability

  • V2X Subscription data

  • ProSe Subscription data

  • MBS Subscription data

Nudm_UEAuthentication service: This service is used by the requester NF to get authentication data and provide UDM with the result of the authentication procedure success. In the case of SNPN, this service may be used to instruct the AUSF to execute authentication towards AAA-S.

Nudm_EventExposure service: The NF consumer subscribes to receive an event, deletes the subscription of an event if already defined in UDM, UDM reports the event to the consumer that has previously subscribed or The NF consumer requests to modify an existing subscription to event notifications.

Nudm_ParameterProvision service : This service is for allowing NEF to provision of information which can be used for the UE in 5GS.

Nudm_NIDDAuthorisation service:  The consumer requests authorisation for NIDD Configuration or is used for the UDM to notify the NIDD Authorization Update to NF consumer.

Nudm_ServiceSpecificAuthorisation service : This service is for authorisation of a specific service configuration.

Nudm_ReportSMDeliveryStatus service: This service is to report the SM-Delivery Status to UDM.

HTTP2_nudr

UDR

HTTP2 + interface + dnn

The Unified Data Repository (UDR) is the database where various types of data are stored. Important data is the subscription data and data defining various types of network or user policies. Usage of UDR to store and access data is offered as services to other network functions, specifically UDM, PCF and NEF.

The operations defined for Nudr services are used when NF service consumers request a set of data from UDR, intends to insert a new data record into the UDR, e.g. a NF service consumer intends to insert a new application data record into the UDR, intends to delete user data stored in the UDR, e.g. a NF service consumer intends to delete an application data record, intends to update stored data in the UDR , NF service consumer performs the subscription to notification to data modified in the UDR or NF service consumer performs the un-subscription to notification to data modified in the UDR.

Reference : 3GPP TS 23.502

HTTP2_nudr_data

UDR

HTTP2 + interface + dnn

The Unified Data Repository (UDR) is the database where various types of data is stored. Important data is of course the subscription data and data defining various types of network or user policies. Usage of UDR to store and access data is offered as services to other network functions, specifically UDM, PCF and NEF.

The operations defined for Nudr services are used when NF service consumers request a set of data from UDR, intends to insert a new data record into the UDR, e.g. a NF service consumer intends to insert a new application data record into the UDR, intends to delete user data stored in the UDR, e.g. a NF service consumer intends to delete an application data record, intends to update stored data in the UDR , NF service consumer performs the subscription to notification to data modified in the UDR or NF service consumer performs the un-subscription to notification to data modified in the UDR. These procedures are specific to data DNN class

Reference : 3GPP TS 23.502

HTTP2_nudr_ims

UDR

HTTP2 + interface + dnn

The Unified Data Repository (UDR) is the database where various types of data is stored. Important data is of course the subscription data and data defining various types of network or user policies. Usage of UDR to store and access data is offered as services to other network functions, specifically UDM, PCF and NEF.

The operations defined for Nudr services are used when NF service consumers request a set of data from UDR, intends to insert a new data record into the UDR, e.g. a NF service consumer intends to insert a new application data record into the UDR, intends to delete user data stored in the UDR, e.g. a NF service consumer intends to delete an application data record, intends to update stored data in the UDR , NF service consumer performs the subscription to notification to data modified in the UDR or NF service consumer performs the un-subscription to notification to data modified in the UDR. These procedures are specific to IMS DNN class

Reference : 3GPP TS 23.502

NAS

NAS (Non-Access Stratum) is a layer in the LTE protocol stack that handles signaling between the User Equipment (UE) and the Evolved NodeB (eNB) in mobile networks. It includes functions related to mobility, security, and session management.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

NAS-5GS_N1

UE--AMF(N1)

NAS-5GS + interface + dnn

A single N1 NAS signaling connection is used for each access to which the UE is connected. The single N1 termination point is located in AMF. The single N1 NAS signaling connection is used for both Registration Management and Connection Management (RM/CM) and for SM-related messages and procedures for a UE.
The NAS protocol on N1 comprises a NAS-MM and a NAS-SM components.
There are multiple cases of protocols between the UE and a core network function (excluding the AMF) that need to be transported over N1 via NAS-MM protocol.
The 5G MM procedures can only be performed if a NAS signaling connection has been established between the UE and the AMF. If there is no active signaling connection, the 5G MM layer has to initiate the establishment of a NAS signaling connection.  When no active connection, the 5GMM layer has to establish NAS signaling by Registration or Service Request procedure

Initial Registration and Setup:

  • Attach Request (UE to AMF): UE initiates the registration process. Includes UE identity, capabilities, and initial registration information.

  • Registration Accept (AMF to UE): AMF accepts the UE registration. Provides necessary information and parameters.

  • Security Activation (UE to AMF): Activation of security mechanisms to protect communication.

  • PDU Session Establishment (UE to AMF): Request for establishing a PDU (Packet Data Unit) session. Includes information like QoS parameters.

UE Context Release:

  • Detach Request (UE to AMF): UE initiates detachment from the network. May include reasons for detachment.

  • UE Context Release Command (AMF to UE): AMF commands the UE to release its context.

Reference : 3GPP TS 23.501 , TS 38.413, TS 38.401 and TS 38.410

NAS-5GS_N1_data

UE--AMF(N1)

NAS-5GS + interface + dnn

A single N1 NAS signaling connection is used for each access to which the UE is connected. The single N1 termination point is located in AMF. The single N1 NAS signaling connection is used for both Registration Management and Connection Management (RM/CM) and for SM-related messages and procedures for a UE.
The NAS protocol on N1 comprises a NAS-MM and a NAS-SM components.
There are multiple cases of protocols between the UE and a core network function (excluding the AMF) that need to be transported over N1 via NAS-MM protocol.
The 5G MM procedures can only be performed if a NAS signaling connection has been established between the UE and the AMF. If there is no active signaling connection, the 5G MM layer has to initiate the establishment of a NAS signaling connection.  When no active connection, the 5GMM layer has to establish NAS signaling by Registration or Service Request procedure

Initial Registration and Setup:

  • Attach Request (UE to AMF): UE initiates the registration process. Includes UE identity, capabilities, and initial registration information.

  • Registration Accept (AMF to UE): AMF accepts the UE registration. Provides necessary information and parameters.

  • Security Activation (UE to AMF): Activation of security mechanisms to protect communication.

  • PDU Session Establishment (UE to AMF): Request for establishing a PDU (Packet Data Unit) session. Includes information like QoS parameters.

UE Context Release:

  • Detach Request (UE to AMF): UE initiates detachment from the network. May include reasons for detachment.

  • UE Context Release Command (AMF to UE): AMF commands the UE to release its context.

Reference : 3GPP TS 23.501 , TS 38.413, TS 38.401 and TS 38.410

NAS-5GS_N1_ims

UE--AMF(N1)

NAS-5GS + interface + dnn

A single N1 NAS signaling connection is used for each access to which the UE is connected. The single N1 termination point is located in AMF. The single N1 NAS signaling connection is used for both Registration Management and Connection Management (RM/CM) and for SM-related messages and procedures for a UE.
The NAS protocol on N1 comprises a NAS-MM and a NAS-SM components.
There are multiple cases of protocols between the UE and a core network function (excluding the AMF) that need to be transported over N1 via NAS-MM protocol.
The 5G MM procedures can only be performed if a NAS signaling connection has been established between the UE and the AMF. If there is no active signaling connection, the 5G MM layer has to initiate the establishment of a NAS signaling connection.  When no active connection, the 5GMM layer has to establish NAS signaling by Registration or Service Request procedure

Initial Registration and Setup:

  • Attach Request (UE to AMF): UE initiates the registration process. Includes UE identity, capabilities, and initial registration information.

  • Registration Accept (AMF to UE): AMF accepts the UE registration. Provides necessary information and parameters.

  • Security Activation (UE to AMF): Activation of security mechanisms to protect communication.

  • PDU Session Establishment (UE to AMF): Request for establishing a PDU (Packet Data Unit) session. Includes information like QoS parameters.

UE Context Release:

  • Detach Request (UE to AMF): UE initiates detachment from the network. May include reasons for detachment.

  • UE Context Release Command (AMF to UE): AMF commands the UE to release its context.

Reference : 3GPP TS 23.501 , TS 38.413, TS 38.401 and TS 38.410

NAS-5GS_N1_sos

UE--AMF(N1)

NAS-5GS + interface + dnn

A single N1 NAS signaling connection is used for each access to which the UE is connected. The single N1 termination point is located in AMF. The single N1 NAS signaling connection is used for both Registration Management and Connection Management (RM/CM) and for SM-related messages and procedures for a UE.
The NAS protocol on N1 comprises a NAS-MM and a NAS-SM components.
There are multiple cases of protocols between the UE and a core network function (excluding the AMF) that need to be transported over N1 via NAS-MM protocol.
The 5G MM procedures can only be performed if a NAS signaling connection has been established between the UE and the AMF. If there is no active signaling connection, the 5G MM layer has to initiate the establishment of a NAS signaling connection.  When no active connection, the 5GMM layer has to establish NAS signaling by Registration or Service Request procedure

Initial Registration and Setup:

  • Attach Request (UE to AMF): UE initiates the registration process. Includes UE identity, capabilities, and initial registration information.

  • Registration Accept (AMF to UE): AMF accepts the UE registration. Provides necessary information and parameters.

  • Security Activation (UE to AMF): Activation of security mechanisms to protect communication.

  • PDU Session Establishment (UE to AMF): Request for establishing a PDU (Packet Data Unit) session. Includes information like QoS parameters.

UE Context Release:

  • Detach Request (UE to AMF): UE initiates detachment from the network. May include reasons for detachment.

  • UE Context Release Command (AMF to UE): AMF commands the UE to release its context.

Reference : 3GPP TS 23.501 , TS 38.413, TS 38.401 and TS 38.410

NGAP

NGAP (Next Generation Application Part) is a protocol used in 5G networks for communication between various control plane elements. It plays a role similar to S1AP (used in LTE) and facilitates signaling between different nodes in the 5G architecture.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

NGAP_N2

RAN--AMF(N2)

NGAP + interface + dnn

The following procedures are defined over N2:

  • Procedures related with N2 Interface Management and that are not related to an individual UE, such as for Configuration or Reset of the N2 interface. These procedures are intended to be applicable to any access but may correspond to messages that carry some information only on some access (such as information on the default Paging DRX used only for 3GPP access).

  • Procedures related with an individual UE:

  • Procedures related with NAS Transport. These procedures are intended to be applicable to any access but may correspond to messages that for UL NAS transport carry some access dependent information such as User Location Information (e.g. Cell-Id over 3GPP access or other kind of User Location Information for Non-3GPP access).

  • Procedures related with UE context management. These procedures are intended to be applicable to any access. The corresponding messages may carry:

                > some information only on some access (such as Mobility Restriction List used only for 3GPP access).
                > some information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with resources for PDU Sessions. These procedures are intended to be applicable to any access. They may correspond to messages that carry information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with Hand-Over management. These procedures are intended for 3GPP access only.

N2 Interface (N2AP):

Path Switching and Data Forwarding:

  • Handover Request (Source gNB to Target gNB): Initiated during handover. Requests the target gNB to prepare for the handover.

  • Handover Command (Target gNB to Source gNB):Instructs the source gNB to release resources and forward data to the target gNB.

  • Handover Preparation Failure (Target gNB to Source gNB): Indicates failure in handover preparation. May result in fallback or reattempt.

User Plane Function Setup and Release:

  • PDU Session Establishment Request (AMF to SMF): Initiates the establishment of a PDU session.

  • PDU Session Establishment Accept (SMF to AMF): Confirms the establishment of the PDU session.

  • PDU Session Modification Request (AMF to SMF): Requests modification of an existing PDU session.

  • PDU Session Release Request (AMF to SMF): Initiates the release of a PDU session.

  • PDU Session Release Accept (SMF to AMF): Acknowledges the release of the PDU session.

UE Radio Capability Information Transfer:

  • UE Capability Info Transfer (Source gNB to Target gNB): Transfers UE radio capabilities during handover preparation.

  • UE Capability Info Transfer (N2IWF to N2IWF): Transfers UE radio capabilities between N2 interfaces.

Reference : 3GPP TS 23.501 , TS 38.413, TS 38.401 and TS 38.410

NGAP_N2_data

RAN--AMF(N2)

NGAP + interface + dnn

The following procedures are defined over N2:

  • Procedures related with N2 Interface Management and that are not related to an individual UE, such as for Configuration or Reset of the N2 interface. These procedures are intended to be applicable to any access but may correspond to messages that carry some information only on some access (such as information on the default Paging DRX used only for 3GPP access).

  • Procedures related with an individual UE:

  • Procedures related with NAS Transport. These procedures are intended to be applicable to any access but may correspond to messages that for UL NAS transport carry some access dependent information such as User Location Information (e.g. Cell-Id over 3GPP access or other kind of User Location Information for Non-3GPP access).

  • Procedures related with UE context management. These procedures are intended to be applicable to any access. The corresponding messages may carry:

                > some information only on some access (such as Mobility Restriction List used only for 3GPP access).
                > some information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with resources for PDU Sessions. These procedures are intended to be applicable to any access. They may correspond to messages that carry information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with Hand-Over management. These procedures are intended for 3GPP access only.

N2 Interface (N2AP):

Path Switching and Data Forwarding:

  • Handover Request (Source gNB to Target gNB): Initiated during handover. Requests the target gNB to prepare for the handover.

  • Handover Command (Target gNB to Source gNB):Instructs the source gNB to release resources and forward data to the target gNB.

  • Handover Preparation Failure (Target gNB to Source gNB): Indicates failure in handover preparation. May result in fallback or reattempt.

User Plane Function Setup and Release:

  • PDU Session Establishment Request (AMF to SMF): Initiates the establishment of a PDU session.

  • PDU Session Establishment Accept (SMF to AMF): Confirms the establishment of the PDU session.

  • PDU Session Modification Request (AMF to SMF): Requests modification of an existing PDU session.

  • PDU Session Release Request (AMF to SMF): Initiates the release of a PDU session.

  • PDU Session Release Accept (SMF to AMF): Acknowledges the release of the PDU session.

UE Radio Capability Information Transfer:

  • UE Capability Info Transfer (Source gNB to Target gNB): Transfers UE radio capabilities during handover preparation.

  • UE Capability Info Transfer (N2IWF to N2IWF): Transfers UE radio capabilities between N2 interfaces.

NGAP_N2_ims

RAN--AMF(N2)

NGAP + interface + dnn

The following procedures are defined over N2:

  • Procedures related with N2 Interface Management and that are not related to an individual UE, such as for Configuration or Reset of the N2 interface. These procedures are intended to be applicable to any access but may correspond to messages that carry some information only on some access (such as information on the default Paging DRX used only for 3GPP access).

  • Procedures related with an individual UE:

  • Procedures related with NAS Transport. These procedures are intended to be applicable to any access but may correspond to messages that for UL NAS transport carry some access dependent information such as User Location Information (e.g. Cell-Id over 3GPP access or other kind of User Location Information for Non-3GPP access).

  • Procedures related with UE context management. These procedures are intended to be applicable to any access. The corresponding messages may carry:

                > some information only on some access (such as Mobility Restriction List used only for 3GPP access).
                > some information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with resources for PDU Sessions. These procedures are intended to be applicable to any access. They may correspond to messages that carry information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with Hand-Over management. These procedures are intended for 3GPP access only.

N2 Interface (N2AP):

Path Switching and Data Forwarding:

  • Handover Request (Source gNB to Target gNB): Initiated during handover. Requests the target gNB to prepare for the handover.

  • Handover Command (Target gNB to Source gNB):Instructs the source gNB to release resources and forward data to the target gNB.

  • Handover Preparation Failure (Target gNB to Source gNB): Indicates failure in handover preparation. May result in fallback or reattempt.

User Plane Function Setup and Release:

  • PDU Session Establishment Request (AMF to SMF): Initiates the establishment of a PDU session.

  • PDU Session Establishment Accept (SMF to AMF): Confirms the establishment of the PDU session.

  • PDU Session Modification Request (AMF to SMF): Requests modification of an existing PDU session.

  • PDU Session Release Request (AMF to SMF): Initiates the release of a PDU session.

  • PDU Session Release Accept (SMF to AMF): Acknowledges the release of the PDU session.

UE Radio Capability Information Transfer:

  • UE Capability Info Transfer (Source gNB to Target gNB): Transfers UE radio capabilities during handover preparation.

  • UE Capability Info Transfer (N2IWF to N2IWF): Transfers UE radio capabilities between N2 interfaces.

NGAP_N2_sos

RAN--AMF(N2)

NGAP + interface + dnn

The following procedures are defined over N2:

  • Procedures related with N2 Interface Management and that are not related to an individual UE, such as for Configuration or Reset of the N2 interface. These procedures are intended to be applicable to any access but may correspond to messages that carry some information only on some access (such as information on the default Paging DRX used only for 3GPP access).

  • Procedures related with an individual UE:

  • Procedures related with NAS Transport. These procedures are intended to be applicable to any access but may correspond to messages that for UL NAS transport carry some access dependent information such as User Location Information (e.g. Cell-Id over 3GPP access or other kind of User Location Information for Non-3GPP access).

  • Procedures related with UE context management. These procedures are intended to be applicable to any access. The corresponding messages may carry:

                > some information only on some access (such as Mobility Restriction List used only for 3GPP access).
                > some information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with resources for PDU Sessions. These procedures are intended to be applicable to any access. They may correspond to messages that carry information (related e.g. with N3 addressing and with QoS requirements) that is to be transparently forwarded by AMF between the 5G-AN and the SMF.

  • Procedures related with Hand-Over management. These procedures are intended for 3GPP access only.

N2 Interface (N2AP):

Path Switching and Data Forwarding:

  • Handover Request (Source gNB to Target gNB): Initiated during handover. Requests the target gNB to prepare for the handover.

  • Handover Command (Target gNB to Source gNB):Instructs the source gNB to release resources and forward data to the target gNB.

  • Handover Preparation Failure (Target gNB to Source gNB): Indicates failure in handover preparation. May result in fallback or reattempt.

User Plane Function Setup and Release:

  • PDU Session Establishment Request (AMF to SMF): Initiates the establishment of a PDU session.

  • PDU Session Establishment Accept (SMF to AMF): Confirms the establishment of the PDU session.

  • PDU Session Modification Request (AMF to SMF): Requests modification of an existing PDU session.

  • PDU Session Release Request (AMF to SMF): Initiates the release of a PDU session.

  • PDU Session Release Accept (SMF to AMF): Acknowledges the release of the PDU session.

UE Radio Capability Information Transfer:

  • UE Capability Info Transfer (Source gNB to Target gNB): Transfers UE radio capabilities during handover preparation.

  • UE Capability Info Transfer (N2IWF to N2IWF): Transfers UE radio capabilities between N2 interfaces.

PFCP

PFCP (Packet Forwarding Control Protocol) is a protocol used in the control plane of the User Plane Function (UPF) in 5G networks. It is responsible for the control of user plane traffic and policies in the 5G architecture.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

PFCP_N4

SMF--UPF(N4)

PFCP + interface + dnn

In 5G, CUPS was applied from the outset, that is, in Release 15. The equivalent control plane and user plane nodes are Session Management Function (SMF) and User Plane Function (UPF). These are connected via the N4 interface. PFCP is used on this interface.

PFCP Node Related Procedures

  • Heartbeat Procedure

  • Load Control Procedure

  • Overload Control Procedure

  • PFCP PFD Management Procedure

  • PFCP Association Setup Procedure

  • PFCP Association Update Procedure

  • PFCP Association Release Procedure

  • PFCP Node Report Procedure

PFCP Session Related Procedures

  • PFCP Session Establishment Procedure

  • PFCP Session Modification Procedure

  • PFCP Session Deletion Procedure

  • PFCP Session Report Procedure

Reference : 3GPP TS 29.244

PFCP_N4_data

SMF--UPF(N4)

PFCP + interface + dnn

In 5G, CUPS was applied from the outset, that is, in Release 15. The equivalent control plane and user plane nodes are Session Management Function (SMF) and User Plane Function (UPF). These are connected via the N4 interface. PFCP is used on this interface.

PFCP Node Related Procedures

  • Heartbeat Procedure

  • Load Control Procedure

  • Overload Control Procedure

  • PFCP PFD Management Procedure

  • PFCP Association Setup Procedure

  • PFCP Association Update Procedure

  • PFCP Association Release Procedure

  • PFCP Node Report Procedure

PFCP Session Related Procedures

  • PFCP Session Establishment Procedure

  • PFCP Session Modification Procedure

  • PFCP Session Deletion Procedure

  • PFCP Session Report Procedure

Reference : 3GPP TS 29.244

PFCP_N4_ims

SMF--UPF(N4)

PFCP + interface + dnn

In 5G, CUPS was applied from the outset, that is, in Release 15. The equivalent control plane and user plane nodes are Session Management Function (SMF) and User Plane Function (UPF). These are connected via the N4 interface. PFCP is used on this interface.

PFCP Node Related Procedures

  • Heartbeat Procedure

  • Load Control Procedure

  • Overload Control Procedure

  • PFCP PFD Management Procedure

  • PFCP Association Setup Procedure

  • PFCP Association Update Procedure

  • PFCP Association Release Procedure

  • PFCP Node Report Procedure

PFCP Session Related Procedures

  • PFCP Session Establishment Procedure

  • PFCP Session Modification Procedure

  • PFCP Session Deletion Procedure

  • PFCP Session Report Procedure

Reference : 3GPP TS 29.244

S1AP

S1AP (S1 Application Part) is a protocol used in LTE networks for communication between the eNB (Evolved NodeB) and the Mobility Management Entity (MME) during the establishment, maintenance, and release of connections.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

S1AP_EMM

S1-MME/S1-AP

S1AP + nas_eps_category + pdn_class

According to 3GPP TS 24.301 (NAS) There are two types of procedure which can be seen on the NAS layer.

EMM (EPS Mobility Management) Procedure.    
Three types of ESM procedures can be distinguished.

EMM common procedures: An EMM common procedure can always be initiated whilst a NAS signaling connection exists. The procedures belonging to this type are:
Initiated by the NW:
-GUTI reallocation;
-Authentication;
-Security mode control;
-Identification;
-EMM information.
EMM specific procedures: At any time only one UE initiated EMM specific procedure can be running. The procedures belonging to this type are:
Initiated by the UE:

  • Attach

  • Detach

  • Tracking Area Update

  • Normal and periodic tracking area updating procedure

  • Combined tracking area updating procedure

Initiated by the NW:

  • Detach

EMM connection management procedures (S1 mode only):
Initiated by the UE:

  • Service request

Initiated by the UE/NW:

  • Transport of NAS Messages

  • Generic transport of NAS messages procedure

Initiated by the NW:

  • Paging Procedure             

ESM (EPS Session Management) procedure : Two types of ESM procedures can be distinguished.
Procedures related to EPS bearer contexts
         Initiated by the NW: -

  • Default EPS bearer context activation;

  • Dedicated EPS bearer context activation;

  • EPS bearer context modification;

  • EPS bearer context deactivation.

Transaction related procedures
        Initiated by the UE:            

  • PDN connectivity procedure;

  • PDN disconnect procedure;

  • Bearer resource allocation procedure;

  • Bearer resource modification procedure.

        Initiated by the NW:

  • ESM information request procedure.

  • ESM status procedure;

  • Notification procedure

S1AP_ESM

S1-MME/S1-AP

S1AP + nas_eps_category + pdn_class

According to 3GPP TS 24.301 (NAS) There are two types of procedure which can be seen on NAS layer.

EMM (EPS Mobility Management) Procedure.    
Three types of ESM procedures can be distinguished.

EMM common procedures: An EMM common procedure can always be initiated whilst a NAS signalling connection exists.The procedures belonging to this type are:
Initiated by the NW:
-GUTI reallocation;
-Authentication;
-Security mode control;
-Identification;
-EMM information.
EMM specific procedures: At any time only one UE initiated EMM specific procedure can be running.The procedures belonging to this type are:
Initiated by the UE:

  • Attach

  • Detach

  • Tracking Area Update

  • Normal and periodic tracking area updating procedure

  • Combined tracking area updating procedure

Initiated by the NW:

  • Detach

EMM connection management procedures (S1 mode only):
Initiated by the UE:

  • Service request

Initiated by the UE/NW:

  • Transport of NAS Messages

  • Generic transport of NAS messages procedure

Initiated by the NW:

  • Paging Procedure             

 

ESM (EPS Session Management) procedure : Two types of ESM procedures can be distinguished.
Procedures related to EPS bearer contexts
         Initiated by the NW: -

  • Default EPS bearer context activation;

  • Dedicated EPS bearer context activation;

  • EPS bearer context modification;

  • EPS bearer context deactivation.

Transaction related procedures
        Initiated by the UE:            

  • PDN connectivity procedure;

  • PDN disconnect procedure;

  • Bearer resource allocation procedure;

  • Bearer resource modification procedure.

        Initiated by the NW:

  • ESM information request procedure.

  • ESM status procedure;

  • Notification procedure

S1AP_ESM_data

S1-MME/S1-AP

S1AP + nas_eps_category + pdn_class

According to 3GPP TS 24.301 (NAS) There are two types of procedure which can be seen on NAS layer.

EMM (EPS Mobility Management) Procedure.    
Three types of ESM procedures can be distinguished.

EMM common procedures: An EMM common procedure can always be initiated whilst a NAS signalling connection exists.The procedures belonging to this type are:
Initiated by the NW:
-GUTI reallocation;
-Authentication;
-Security mode control;
-Identification;
-EMM information.
EMM specific procedures: At any time only one UE initiated EMM specific procedure can be running.The procedures belonging to this type are:
Initiated by the UE:

  • Attach

  • Detach

  • Tracking Area Update

  • Normal and periodic tracking area updating procedure

  • Combined tracking area updating procedure

Initiated by the NW:

  • Detach

EMM connection management procedures (S1 mode only):
Initiated by the UE:

  • Service request

Initiated by the UE/NW:

  • Transport of NAS Messages

  • Generic transport of NAS messages procedure

Initiated by the NW:

  • Paging Procedure             

 

ESM (EPS Session Management) procedure : Two types of ESM procedures can be distinguished.
Procedures related to EPS bearer contexts
         Initiated by the NW: -

  • Default EPS bearer context activation;

  • Dedicated EPS bearer context activation;

  • EPS bearer context modification;

  • EPS bearer context deactivation.

Transaction related procedures
        Initiated by the UE:            

  • PDN connectivity procedure;

  • PDN disconnect procedure;

  • Bearer resource allocation procedure;

  • Bearer resource modification procedure.

        Initiated by the NW:

  • ESM information request procedure.

  • ESM status procedure;

  • Notification procedure

S1AP_ESM_ims

S1-MME/S1-AP

S1AP + nas_eps_category + pdn_class

According to 3GPP TS 24.301 (NAS) There are two types of procedure which can be seen on NAS layer.

EMM (EPS Mobility Management) Procedure.    
Three types of ESM procedures can be distinguished.

EMM common procedures: An EMM common procedure can always be initiated whilst a NAS signalling connection exists.The procedures belonging to this type are:
Initiated by the NW:
-GUTI reallocation;
-Authentication;
-Security mode control;
-Identification;
-EMM information.
EMM specific procedures: At any time only one UE initiated EMM specific procedure can be running.The procedures belonging to this type are:
Initiated by the UE:

  • Attach

  • Detach

  • Tracking Area Update

  • Normal and periodic tracking area updating procedure

  • Combined tracking area updating procedure

Initiated by the NW:

  • Detach

EMM connection management procedures (S1 mode only):
Initiated by the UE:

  • Service request

Initiated by the UE/NW:

  • Transport of NAS Messages

  • Generic transport of NAS messages procedure

Initiated by the NW:

  • Paging Procedure             

 

ESM (EPS Session Management) procedure : Two types of ESM procedures can be distinguished.
Procedures related to EPS bearer contexts
         Initiated by the NW: -

  • Default EPS bearer context activation;

  • Dedicated EPS bearer context activation;

  • EPS bearer context modification;

  • EPS bearer context deactivation.

Transaction related procedures
        Initiated by the UE:            

  • PDN connectivity procedure;

  • PDN disconnect procedure;

  • Bearer resource allocation procedure;

  • Bearer resource modification procedure.

        Initiated by the NW:

  • ESM information request procedure.

  • ESM status procedure;

  • Notification procedure

S1AP_ESM_sos

S1-MME/S1-AP

S1AP + nas_eps_category + pdn_class

According to 3GPP TS 24.301 (NAS) There are two types of procedure which can be seen on NAS layer.

EMM (EPS Mobility Management) Procedure.    
Three types of ESM procedures can be distinguished.

EMM common procedures: An EMM common procedure can always be initiated whilst a NAS signaling connection exists. The procedures belonging to this type are:
Initiated by the NW:
-GUTI reallocation;
-Authentication;
-Security mode control;
-Identification;
-EMM information.
EMM specific procedures: At any time only one UE initiated EMM specific procedure can be running. The procedures belonging to this type are:
Initiated by the UE:

  • Attach

  • Detach

  • Tracking Area Update

  • Normal and periodic tracking area updating procedure

  • Combined tracking area updating procedure

Initiated by the NW:

  • Detach

EMM connection management procedures (S1 mode only):
Initiated by the UE:

  • Service request

Initiated by the UE/NW:

  • Transport of NAS Messages

  • Generic transport of NAS messages procedure

Initiated by the NW:

  • Paging Procedure             

 

ESM (EPS Session Management) procedure : Two types of ESM procedures can be distinguished.
Procedures related to EPS bearer contexts
         Initiated by the NW: -

  • Default EPS bearer context activation;

  • Dedicated EPS bearer context activation;

  • EPS bearer context modification;

  • EPS bearer context deactivation.

Transaction related procedures
        Initiated by the UE:            

  • PDN connectivity procedure;

  • PDN disconnect procedure;

  • Bearer resource allocation procedure;

  • Bearer resource modification procedure.

        Initiated by the NW:

  • ESM information request procedure.

  • ESM status procedure;

  • Notification procedure

SIP

SIP (Session Initiation Protocol) is a signaling protocol used for initiating, modifying, and terminating communication sessions, including voice and video calls over IP networks. It is commonly used in VoIP (Voice over Internet Protocol) and multimedia communication applications.

Procedure Name

Interface/NE Name

Structure

Description

Procedure Name

Interface/NE Name

Structure

Description

SIP_Call

UE--P/I/S-CSCF--TAS (Gm-Mw-ISC-Mx-Mr)

SIP + sip_subflow_type

The establishment of the VoLTE session (call) includes the following operations:
– the negotiation of the characteristics of real-time transport protocol
(RTP) streams via session description protocol (SDP);
– the establishment of dedicated bearer to the RTP stream.

The initial stages of setting up a VoLTE call are the processes of the initial attach, P-CSCF discovery and creating the default bearer for SIP signaling (by registering with the IMS network and subscribing to a registration event package).

The first step in a VoLTE call setup is a SIP INVITE request initiated by the calling UE. Following this step, agreement is made on the media-specific parameters such as codecs (e.g. AMR or WB-AMR). After some RINGING, TRYING and OK messaging, the calling UE may respond with a Provisional ACK (PRACK) method as defined in RFC 3551. The PRACK method is used because ACK cannot safely traverse proxy servers that comply with RFC 3261. The PRACK is also forwarded to the called UE. When the called subscriber answers the call, the called UE will respond with a 200 OK before the RTP (media) messaging begins.

Reference : 3GPP TS 24.229

SIP_De-Registration

UE--P/I/S-CSCF--HSS (Gm-Mw-Cx)

SIP + sip_subflow_type

The deregistration phase starts when the UA entity transmits a REGISTER message which parameter expires of the header Contact has a zero value.

  • The I-CSCF entity transmits to the HSS entity the DIAMETER LIR message to retrieve the IP address of S-CSCF.

  • The HSS entity provides the IP address of the S-CSCF entity in the DIAMETER LIA message.

  • The I-CSCF entity sends to the S-CSCF entity the REGISTER request.

  • The S-CSCF entity transmits to the HSS entity the DIAMETER SAR message informing about deregistration of the mobile. The HSS entity still retains the identity of the S-CSCF entity to allow the use of services when the mobile is not registered, such as call forwarding to voicemail.

  • The HSS entity transmits the DIAMETER SAA message to acknowledge the previous request.

  • The S-CSCF entity informs UA entity of its deregistration in a NOTIFY message.

  • The 200 OK message is a response to the NOTIFY request.

  • The S-CSCF entity informs the TAS entity about the deregistration of UA entity in a NOTIFY message.

  • The 200 OK message is a response to the NOTIFY request.

  • The S-CSCF entity informs the P-CSCF entity about the deregistration of UA entity in a NOTIFY message.

  • The 200 OK message is a response to the NOTIFY request.

  • The 200 OK message is a response to the REGISTER request.

Reference : 3GPP TS 24.229

SIP_Registration

UE--P/I/S-CSCF--HSS (Gm-Mw-Cx)

SIP + sip_subflow_type

After Authentication, Security and UE Capability requests, the network accepts the Attach request and activates the EPS bearer context. Once that has happened and the UE has also established a PDP context, a typical IMS SIP client registration (Figure 4) begins:

  • The IMS client attempts to register by sending a REGISTER request to the P-CSCF.

  • The P-CSCF forwards the REGISTER request to the I-CSCF.

  • The I-CSCF polls the HSS for data used to decide which S-CSCF should manage the REGISTER request. The I-CSCF then makes that decision.

  • The I-CSCF forwards the REGISTER request to the appropriate S-CSCF.

  • The S-CSCF typically sends the P-CSCF a 401 (UNAUTHORIZED) response as well as a challenge string in the form of a “number used once” or “nonce”.

  • The P-CSCF forwards the 401 – UNAUTHORIZED response to the UE.

  • Both the UE and the network have stored some Shared Secret Data (SSD), the UE in its ISIM or USIM and the network on the HSS. The UE uses an algorithm per RFC 33101 (e.g. AKAv2-MD5) to hash the SSD and the "nonce".

  • The UE sends a REGISTER request to the P-CSCF. This time the request includes the result of the hashed nonce and SSD.

  • The P-CSCF forwards the new REGISTER request to the I-CSCF.

  • The I-CSCF forwards the new REGISTER request to the S-CSCF.

  • The S-CSCF polls the HSS (via the I-CSCF) for the SSD, hashes it against the nonce and determines whether the UE should be allowed to register. Assuming the hashed values match, the S-CSCF sends 200 – OK response to the P-CSCF. At this point an IPSec security association is established by the P-CSCF.

  • The P-CSCF forwards the 200 – OK response to the UE.

Reference : 3GPP TS 24.229