The following diagram illustrates the various data paths possible with and without CIoT EPS optimization for IP and non-IP data.

• S1 interface: Exists between the eNodeB (RAN) and MME. It carries the signaling for data radio bearer (DRB) setup and NAS PDU (includes UE signaling and small data over NAS).

• NAS: The Non-Access Stratum (NAS) is a set of protocols between the UE and MME. It carries the UE signaling data for mobility management and session management. NAS allows small data to be transmitted using the Signaling Radio Bearer (SRB) over the S1AP protocol.

• S1-U interface: Exists between the E-UTRAN and S-GW for per bearer user plane tunneling and inter-eNodeB path switching during handover.

• S5-C interface: Exists between the S-GW and P-GW to control signaling. It is a GTPv2 control interface for tunnel management, creation/modification/deletion of per bearer user plane tunneling on the S5-U interface.

• S5-U interface: Exists between the S-GW and P-GW for user plane tunneling between S-GW and P-GW. It is a GTPv1 user plane interface for carrying IP and non-IP data within GTP-U.

• S11-C interface: Exists between the MME and S-GW to control signaling. It is a GTPv2 control interface for creation or modification or deletion of per bearer user plane tunneling on the S1-U and S11-U interfaces.

• S11-U interface: Exists between the MME and S-GW. It is a GTPv1 user plane interface and allows small data transmission over NAS between MME and S-GW.

• SGi interface: Exists between the P-GW and packet data network (PDN). The PDN can be an operator’s external public or private packet data network or an intra-operator packet data network.

• T6a interface: Exists between the SCEF and MME. It enables transfer of non-IP data between MME and SCEF.

IP data over S1-U is the traditional IP data path from the UE to eNodeB over DRB and the eNodeB to S-GW over S1-U. IP data over S11-U makes use of CP CIoT optimization. The data path from the UE to eNodeB is over SRB, eNodeB to MME is over S1AP/NAS, and MME to S-GW is over the S11-U interface.

Non-IP data over S1-U interface is the traditional data path from the UE to eNodeB over DRB and the eNodeB to S-GW over S1-U. Non-IP data over S11-U makes use of CP CIoT optimization. The data path from the UE to eNodeB is over SRB, eNodeB to MME is over S1AP/NAS, and MME to S-GW is over the S11-U interface.

Non-IP data over T6a makes use of CP CIoT optimization. The data path from UE to the eNodeB is over SRB, eNodeB to MME is over NAS/S1AP, and MME to SCEF is over the T6a interface.

The MME supports other CIoT optimization functions in order to provide support for IoT devices in the EPS network. The related features are:

• MME support for CIoT devices

• CIoT Optimizations for NB-IoT RAT and Attach Without PDN Connectivity Support

• Non-IP data over SCEF

• SMS over MME without SGs or CS attach

Refer to the other feature chapters in this guide for more information.

The known limitations with this feature are listed below:

• The MME does not support buffering of data.

• The MME does not support User Plane CIoT optimization.

• The maximum size of NAS PDU supported is 2KB.

• Switching data path from control plane CIoT optimization to S1-U while the UE is in ECM-connected state is not supported.

• Enforcement of Serving PLMN rate limit is not done at the MME.

• Inter-MME/SGSN handovers are not supported when control plane CIoT optimization is implemented (for both IP and non-IP).

• Intra-MME handovers are not supported when control plane CIoT optimization is implemented (for both IP and non-IP).

• Inter-MME/SGSN idle mode handovers are not supported when control plane CIoT optimization is implemented (for both IP and Non-IP).

• APN remap is not supported for non-IP PDN type.

• Idle mode handover to peer SGSN is not supported for Non-IP SGi PDNs.

• IPv6 is not supported for the S11-U interface.

• Execution of the associate or no associate command in the GTPU service under the MME EGTP service restarts the MME service.

• Removal or addition of the GTPU service that is already associated with the MME EGTP service restarts the MME service.

Attach with PDN using CP CIoT Optimization (SGi Path)

The following call flow diagram displays the Attach with PDN procedure with CP CIoT optimization.

This call flow does not display the following:

• HSS interaction for authentication and S6a Location update

• UE authentication

• Security setup

However, these procedures are applicable and performed by the MME for this call flow.

Attach with CP CIoT optimization performs bearer setup on the UE and network (SGi/SCEF) without reserving radio resources in the RAN. Data Radio Bearer (DRB) is not setup on the eNodeB for the UE. Signaling Radio Bearer (SRB) is used for all communication over the air interface between UE and the eNodeB. The MME does not send the S1 Initial Context Setup request to the eNodeB. The eNodeB does not send RRC re-configuration to the UE as there is no Initial Context Setup at the eNodeB. The MME sends a NAS Attach Accept to the UE in S1 Downlink NAS Transport message instead of S1 Initial Context Setup request. The UE sends NAS Attach Complete in the S1 Uplink NAS Transport message. The MME establishes the S11-U tunnel during S11 Create Session request/response signalling. S11 Modify Bearer request sent is not sent to the S-GW after Attach Complete is received from UE.

Step 1: The UE sends the RRC connection set up complete message and the NAS attach request to the eNodeB.

Step 2: The eNodeB sends the S1AP Initial UE Message, NAS attach request message and ESM PDN connectivity request to the MME.

Step 3: The MME sends the S11 create session request to the S-GW.

Step 4: The S-GW responds to the MME with the S11 create session response.

Step 5: The MME sends the S1AP downlink NAS message, NAS attach accept and ESM activate default bearer request to the eNodeB.

Step 6: The eNodeB in turn sends the RRC downlink information transfer message, NAS attach accept and ESM activate default bearer request to the UE.

Step 7: The UE sends the RRC uplink information transfer message, NAS attach complete and an ESM activate default bearer accept message to the eNodeB.

Step 8: The eNodeB sends the S1AP uplink NAS message, NAS attach complete and ESM activate default bearer accept message to the MME.

Additional PDN Connection with CP CIoT Optimization

The following call flow diagram displays the additional PDN connection procedure with CP CIoT optimization.

This call flow does not display the HSS interaction for S6a notify request.

However, these procedures are applicable and performed by the MME for this call flow.

Additional PDN connection with CP CIoT optimization performs bearer setup on the UE and network (SGi/SCEF) without reserving radio resources in the RAN. Data Radio Bearer (DRB) is not setup on the eNodeB for the UE. Signaling Radio Bearer (SRB) is used for all communication over the air interface between UE and eNodeB. The MME does not send S1 ERAB Setup request to eNodeB. The eNodeB does not send RRC reconfiguration to the UE as there is no S1 ERAB Setup at the eNodeB. The MME sends a NAS Activate default EPS bearer context request to UE in S1 Downlink NAS Transport message instead of S1 ERAB Setup request. The UE sends NAS Activate Default Bearer Accept in the S1 Uplink NAS Transport message. The MME establishes the S11-U tunnel during S11 Create Session request/response signaling. S11 Modify Bearer request is not sent to the S-GW after Activate Default Bearer Accept is received from UE.

Step 1: The UE sends the RRC uplink information transfer message and the NAS PDN connectivity request to the eNodeB.

Step 2: The eNodeB sends the S1AP uplink NAS transport Message and the NAS PDN connectivity request to the MME.

Step 3: The MME sends the S11 create session request to the S-GW.

Step 4: The S-GW responds to the MME with the S11 create session response.

Step 5: The MME sends the S1AP downlink NAS transport message and the NAS activate default bearer request to the eNodeB.

Step 6: The eNodeB in turn sends the RRC downlink information transfer message and the NAS activate default bearer request accept to the UE.

Step 7: The UE sends the RRC uplink information transfer message and the NAS activate default bearer accept message to the eNodeB.

Step 8: The eNodeB sends the S1AP uplink NAS message and the NAS activate default bearer accept message to the MME.

Idle to Active Transition with Control Plane Service Request

The following call flow diagram displays an Idle to Active mode state transition for a CIoT UE.

A CIoT UE transitioning from idle to active mode does not reserve any radio resources in the RAN. Data Radio Bearer (DRB) is not setup on the eNodeB for the UE. Signaling Radio Bearer (SRB) is used for all communication over the air interface between UE and the eNodeB. The MME does not send S1 Initial Context Setup request to the eNodeB. The eNodeB does not send RRC re-configuration to the UE as there is no Initial Context Setup at the eNodeB. The MME sends a NAS Service Accept to UE in S1 Downlink NAS Transport message and it brings up S11U tunnel for each SGi PDN through S11 Modify Bearer request/response signaling with the S-GW.

Step 1: The UE sends the RRC connection set up complete message and NAS control plane service request to the eNodeB.

Step 2: The eNodeB sends the S1AP initial UE message and NAS control plane service request to the MME.

Step 3: The MME sends the S11 modify bearer request to the S-GW for each SGi PDN.

Step 4: The S-GW responds to the MME with the S11 modify bearer response for each SGi PDN.

Step 5: The MME sends the S1AP downlink NAS transport message and NAS service accept message to the eNodeB.

Step 6: The eNodeB in turn sends the RRC downlink information transfer message and the NAS service accept message to the UE.

MO and MT Data Exchange with CP CIoT Optimization

The following call flow diagram displays MO and MT data exchange with CIoT UE in active state (connected mode).

MO and MT data exchange utilizes the SRB to carry data over NAS. The MME receives the ESM payload in NAS message from the UE and sends it to the S-GW over GTP-U using S11-U tunnel. The MME receives the GTP-U payload from S-GW over S11-U tunnel and sends it to the UE in a NAS message.

MO data can be sent by the UE to MME in the following NAS messages:

• NAS Control Plane Service Request

• NAS ESM Data Transport Message

MT data can be sent by the MME to the UE in the "NAS ESM Data Transport Message" message.

Step 1: The UE sends the RRC uplink information transfer message and the NAS ESM data transport message to the eNodeB.

Step 2: The eNodeB sends the uplink NAS transport message and the NAS ESM data transport message to the MME.

Step 3: The MME sends the S11-U GTP-U message to the S-GW for MO data.

Step 4: The S-GW responds to the MME with the S11-U GTP-U message for MT data.

Step 5: The MME sends the S1AP downlink NAS transport message and the NAS ESM data transport message to the eNodeB.

Step 6: The eNodeB in turn sends the RRC downlink information transfer message and the NAS ESM data transport message to the UE.

The Small Data over NAS, S11-U and SGi Interfaces feature complies with the following standards:

• 3GPP TS 36.413 v13.4.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access Network (E-UTRAN); S1 Application Protocol (S1AP) (Release 13)

• 3GPP TS 23.401 v13.8.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; General Packet Radio Service (GPRS) enhancements for Evolved Universal Terrestrial Radio Access Network (E-UTRAN) access (Release 13)

• 3GPP TS 24.301 v13.7.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Non-Access-Stratum (NAS) protocol for Evolved Packet System (EPS); Stage 3 (Release 13)

• 3GPP TS 29.272 v13.7.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; Evolved Packet System (EPS); Mobility Management Entity (MME) and Serving GPRS Support Node (SGSN) related interfaces based on Diameter protocol (Release 13)

• 3GPP TS 29.274 v13.7.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Core Network and Terminals; 3GPP Evolved Packet System (EPS); Evolved General Packet Radio Service (GPRS) Tunneling Protocol for Control plane (GTPv2-C); Stage 3 (Release 13)

• 3GPP TS 23.682 v13.7.0 (2016-09), 3rd Generation Partnership Project; Technical Specification Group Services and System Aspects; Architecture enhancements to facilitate communications with packet data networks and applications (Release 13)

The ciot-optimisation CLI command has been introduced under the Call Control Profile to enable CIoT optimization for an UE.

configure 
   call-control-profile profile_name 
      ciot-optimisation [ cp-optimisation access-type { all | nb-iot | wb-eutran } | eps-attach-wo-pdn access-type { all | nb-iot | wb-eutran } ] 
      remove ciot-optimisation cp-optimisation 
      remove ciot-optimisation eps-attach-wo-pdn access-type { all | nb-iot | wb-eutran } 
      exit 

Notes:

• The ciot-optimisation command enables CIoT optimization for an UE.

• The cp-optimisation keyword enables Control Plane optimization for an UE.

• The remove keyword deletes the existing configuration.

• The access-type keyword specifies the access type extension on which control plane optimization must be enabled. Control plane optimization can be enabled on both NB-IoT and WB-EUTRAN RATs or on either of them. Enabling one RAT type overrides the existing configuration.

• The all keyword enables control plane optimization for all access types. Both NB-IoT and WB-EUTRAN are considered as two independent access types for all functions.

• The nb-iot keyword enables control plane optimization for NB-IoT access type.

• The wb-eutran keyword enables control plane optimization for WB-EUTRAN access type.

• The eps-attach-wo-pdn keyword enables EPS attach without PDN support for an UE.

• The call-control-profile can be associated with the operator-policy and the CIoT optimization can be enabled or disabled on a per subscriber (IMSI) basis.

• This command is disabled by default.

Verifying the Configuration

Execute the show call-control-profile full name profile-name command to verify the configured values. For example:

show call-control-profile full name profile_name 
   CIoT Optimisation: 
      CIoT Optimisation:  Enabled/Disabled 
      Access-Type:  all/nb-iot/wb-eutran/N/A 

The pdn-type CLI command added in the APN Profile Configuration mode specifies the PDN type indicator in the APN profile.

configure 
   apn-profile profile_name 
      pdn-type { ip | non-ip { sgi | t6a [ scef-id scef_id [ scef-realm realm_name ] ] } } 
      remove pdn-type 
      exit 

Notes:

• Use this command to specify the Cellular IoT PDN type. The user has an option to override the HSS provided APN subscription PDN type. This command is applicable only during Attach and additional PDN connectivity, and not during Handover scenarios.

• The remove keyword deletes the existing configuration.

• The ip keyword configures the Cellular IoT PDN type as IP PDN.

• The non-ip keyword configures the Cellular IoT PDN type as non-IP PDN.

• The sgi keyword configures the Cellular IoT Non-IP PDN delivery path type as SGi.

• The t6a keyword configures the Cellular IoT Non-IP PDN delivery path type as T6a.

• The scef-id scef_id keyword optionally specifies the SCEF ID. The scef_id is an alphanumeric string of 1 to 63 characters.

• The scef-realm realm_name keyword optionally specifies the SCEF diameter realm name. The realm_name is an alphanumeric string of 1 to 127 characters.

• This command is disabled by default.

Verifying the Configuration

Execute the show apn-profile profile_name command to verify the configured values. For example:

show apn-profile full name profile_name 
PDN Type					                   : NON-IP/IP/Not configured 
NON-IP Delivery Mechanism Type	 : SGi/T6a 
SCEF-Id				                     : SCEF_Identifier 
SCEF-Realm				                  : SCEF_diameter_realm_name 

The serving-plmn-rate-control CLI command added in the Call Control Profile Configuration mode configures the serving PLMN rate control for control plane CIoT optimization. The serving PLMN rate control limits the rate at which UE or P-GW / SCEF sends data over the control plane when CP optimization is enabled.

configure 
   call-control-profile profile_name 
      serving-plmn-rate-control ul-rate ul_rate_value dl-rate dl_rate_value 
      remove serving-plmn-rate-control 
      exit 

Notes:

• The remove keyword deletes the existing configuration.

• The ul-rate ul_rate_value keyword configures the maximum number of data NAS PDUs that the UE can send in uplink path per deci-hour (6 minutes). The uplink rate is an integer from 10 up to 65535. A value of 65535 in this case implies no limit on the number of PDUs that the UE can send in the uplink path per deci-hour.

• The dl-rate dl_rate_value keyword configures the maximum number of data NAS PDUs that the P-GW / SCEF can send in the downlink path to the UE per deci-hour (6 minutes). The downlink rate is an integer from 10 up to 65535. A value of 65535 in this case implies no limit on the number of PDUs that the P-GW / SCEF can send in the downlink path per deci-hour.

• This command is disabled by default.

Verifying the Configuration

Execute the show call-control-profile full name profile_name command to verify the configured values. For example:

show call-control-profile full name profile_name 
Serving PLMN Rate Control  : Enabled/Disabled 
   UL Rate		               : x pdus per deci hour. 
   DL Rate                 : x pdus per deci hour. 

The ip CLI command added in the APN Profile Configuration mode defines the IP parameters for the APN profile. This command is used to configure:

• SGSN/S-GW action in response to detected IP source violations

• DSCP marking for downlink and uplink configuration per traffic class

• QoS class diffserv code

The s11u-mme keyword is added in this command which is used to configure the S11-U interface parameters.

configure 
   apn-profile profile_name 
      ip { qos-dscp { { { downlink | uplink } { background forwarding | conversational forwarding | interactive traffic-handling-priority priority forwarding | streaming forwarding } + } | s11u-mme value } | source-violation { deactivate [ all-pdp | exclude-from accounting | linked-pdp | tolerance-limit } | discard [ exclude-from-accounting ] | ignore } 
      default ip { qos-dscp [ downlink | uplink | s11u-mme ] | source-violation } 
      no ip qos-dscp { downlink | uplink } { background | conversational | interactive | streaming } + 

Important

All parameters that are not specifically configured will be included in the configuration with default values.

Notes:

• The default keyword resets the configuration to the default values.

• The no keyword disables the specified IP QoS-DSCP mapping.

• The qos-dscp keyword configures the Differentiated Services Code Point (DCSP) marking to be used for sending packets of a particular 3GPP QoS class.

• The s11u-mme keyword configures the S11-U interface parameters. The DSCP values can be specified using this keyword. The DSCP value for S11-U interface can be separately specified for each APN. This keyword is not enabled by default. The default value is “be”.

  The DSCP values configured for the S11-U interface are:

  • af11 - Designates use of Assured Forwarding 11 PHB

  • af12 - Designates use of Assured Forwarding 12 PHB

  • af13 - Designates use of Assured Forwarding 13 PHB

  • af21 - Designates use of Assured Forwarding 21 PHB

  • af22 - Designates use of Assured Forwarding 22 PHB

  • af23 - Designates use of Assured Forwarding 23 PHB

  • af31 - Designates use of Assured Forwarding 31 PHB

  • af32 - Designates use of Assured Forwarding 32 PHB

  • af33 - Designates use of Assured Forwarding 33 PHB

  • af41 - Designates use of Assured Forwarding 41 PHB

  • af42 - Designates use of Assured Forwarding 42 PHB

  • af43 - Designates use of Assured Forwarding 43 PHB

  • be - Designates use of Best Effort forwarding PHB

  • cs0 - Designates use of Class Selector 0 PHB

  • cs1 - Designates use of Class Selector 1 PHB

  • cs2 - Designates use of Class Selector 2 PHB

  • cs3 - Designates use of Class Selector 3 PHB

  • cs4 - Designates use of Class Selector 4 PHB

  • cs5 - Designates use of Class Selector 5 PHB

  • cs6 - Designates use of Class Selector 6 PHB

  • cs7 - Designates use of Class Selector 7 PHB

  • ef - Designates use of Expedited Forwarding PHB

Important

If you modify the interface-type command, the parent service (service within which the eGTP/GTP-U service is configured) will automatically restart. Service restart results in dropping of active calls associated with the parent service.

configure 
             call-control-profile profile_name 
                ciot-optimisation cp-optimisation access-type all 
                ciot-optimisation eps-attach-wo-pdn access-type all 
                exit 
             operator-policy name policy_name 
                associate call-control-profile profile_name 
                apn network-identifier apn_net_id_1 apn-profile apn_profile_name_1 
                apn network-identifier apn_net_id_1 apn-profile apn_profile_name_1 
             exit 
             apn-profile profile_name_1 
                pdn-type non-ip t6a 
             exit 
             apn-profile profile_name_2 
                pdn-type non-ip sgi 
             exit 
             lte-policy 
                 subscriber-map map_name 
                      precedence numbermatch-criteria all operator-policy-name policy_name 
                 exit 
             exit 
             context ingress 
                 mme-service service_name 
                    bind s1-mme ipv4-address ipv4_address 
                    s1-mme sctp port port_number 
                    mme-id group-id id mme-code  code 
                    plmn-id mcc mcc_value  mnc mnc_value  
                    associate egtp-service egtp_svc_name context context_name  
                    associate hss-peer-service svc_name context context_name  
                    associate subscriber-map map_name 
             exit 
             egtp-service service_name 
                 interface-type interface-mme 
                 gtpc bind ipv4-address ipv4_address 
                 associate gtpu-service name 
             exit 
             gtpu-service service_name 
                 bind ipv4-address ipv4_address 
             exit 
           exit 
         end 

The configuration can be verified by issuing the following show commands:

• show configuration

• show mme-service all

• show call-control-profile full all

• show apn-profile full all

show call-control-profile full name profile_name

The following new fields are added to the output of this command to display the configured CP CIoT optimization parameters:

• CIoT Optimisation

• CP-Optimisation

• Access-Type

• Serving PLMN Rate Control

• UL Rate

• DL Rate

show apn-profile full name profile_name

The following new fields are added to the output of this command to display the configured PDN type:

• PDN Type

• Non-IP Delivery Mechanism Type

• SCEF-Id

• SCEF-Realm

show subscriber all

The following new field is added to the output of this command to display the new network type:

• (N) – Non-IP

show mme-service session full all

The following new fields are displayed in the output of this command if CP CIoT optimization is enabled:

• CIoT Optimisation Information

  • NB-IoT RAT

  • Attach Without PDN Support

  • CP-CIoT Optimization

• PDN Type

• PDN Data Delivery Interfacea

• Non-IP Data Delivery Mechanism Identifier

• S11U MME TEID: Displays the S11U MME Tunnel Identifier.

• S11U SGW TEID: Displays the S11U SGW Tunnel Identifier

• S11U MME IPv4 Addr: Displays the S11U MME IPv4 transport address

• S11U MME IPv6 Addr: Displays the S11U MME IPv6 transport address

• S11U SGW IPv4 Addr: Displays the S11U SGW IPv4 transport address

• S11U SGW IPv6 Addr: Displays the S11U SGW IPv6 transport address

show mme-service db record imsi imsi_number

The following new fields are added to the output of this command:

• Non-IP-PDN-Type-Indicator

• Non-IP-Data-Delivery-Mechanism

• SCEF-ID

• SCEF-Realm

show mme-service statistics

The following new ECM statistics are added to display the UE-initiated CP service request events and network-initiated CP service request events. These parameters are displayed only if CP CIoT optimization is enabled.

• UE Initiated CP Service Request Events

  • Attempted

  • Success

  • Failures

• NW Initiated CP Service Request Events

  • Attempted

  • Success

  • Failures

• New EMM message statistics are added to display the number of NAS service accept messages sent, partially ciphered NAS messages received and NAS control plane service request messages received:

  • Service Accept

  • Partially Ciphered messages

  • CP Service Request

• New ESM procedure statistics are added to display the number of Non-IP PDN Connections over SCEF (t6a), Non-IP PDN Connections over SGi (s1u or s11u) and PDN Disconnections over SCEF (t6a) attempted, successful and failed:

  • NON-IP PDN Connections With SCEF

    • Attempted

    • Success

    • Failures

  • NON-IP PDN Connections With SGI

    • Attempted

    • Success

    • Failures

  • NON-IP PDN Connections With SCEF

    • Attempted

    • Success

    • Failures

• New statistics are added to display the Non-IP PDN statistics - the number of non-IP PDN Connections over SCEF (T6a), number of Non-IP PDN Connections over SGi (S1U or S11-U) and all non-IP PDN connections (the total sum of non-IP PDN connections over SCEF and SGi):

  • NON-IP PDN Statistics

  • All PDNs

  • SCEF PDNs

  • SGI PDNs

• New statistics have been added to display the number of attached calls, connected calls and idle calls for NB-IoT subscribers, Attach without PDN subscribers and CP-CIoT enabled subscribers:

  • NB-IoT Subscribers

    • Attached Calls

    • Connected Calls

    • Idle Calls

  • Attach Without PDN Subscribers

    • Attached Calls

    • Connected Calls

    • Idle Calls

  • CP-CIoT Enabled Subscribers

    • Attached Calls

    • Connected Calls

    • Idle Calls

• New statistics have been added to the show output and are grouped according to:

  • Data over NAS statistics

  • IP data over S11-U statistics

  • Non-IP data over S11-U statistics

  • Data over T6a statistics

  Received packets (Rx packets), Received bytes (Rx Bytes), Transmitted packets (Tx Packets), Transmitted Bytes (Tx Bytes), Received packets dropped (Rx Drop Packets), Received Bytes dropped (Rx Drop Bytes), Transmitted packets dropped (Tx Drop Packets) and Transmitted bytes dropped (Tx Drop Bytes) are displayed for each of the above listed group of statistics.

• Data Over NAS Statistics

  • Rx Packets

  • Rx Bytes

  • Tx Packets

  • Tx Bytes

  • Rx Drop Packets

  • Rx Drop Bytes

  • Tx Drop Packets

  • Tx Drop Bytes

• IP Data Over S11U Statistics

  • Rx Packets

  • Rx Bytes

  • Tx Packets

  • Tx Bytes

  • Rx Drop Packets

  • Rx Drop Bytes

  • Tx Drop Packets

  • Tx Drop Bytes

• NON-IP Data Over S11U Statistics

  • Rx Packets

  • Rx Bytes

  • Tx Packets

  • Tx Bytes

  • Rx Drop Packets

  • Rx Drop Bytes

  • Tx Drop Packets

  • Tx Drop Bytes

• Data Over T6A (SCEF) Statistics

  • Rx Packets

  • Rx Bytes

  • Tx Packets

  • Tx Bytes

  • Rx Drop Packets

  • Rx Drop Bytes

  • Tx Drop Packets

  • Tx Drop Bytes

show mme-service statistics verbose

New statistics are added to display number of Idle mode Outbound Relocation using TAU/RAU Denied, Idle mode Outbound Relocation using TAU/RAU with PDN deactivation at MME, Connected mode Outbound Relocation Denied and Connected mode Outbound Relocation with PDN deactivation at MME.

• NON-IP Statistics

  • Outbound Relocation for TAU/RAU - Denied (Context Failure)

  • No SGI Non-IP sup by peer MME

  • No SCEF Non-IP sup by peer MME

• Outbound Relocation for TAU/RAU - PDN Deactivation

  • No SGI Non-IP sup by peer S3 SGSN o No SCEF Non-IP sup by peer S3 SGSN

  • No SGI Non-IP sup by peer Gn SGSN

  • No SCEF Non-IP sup by peer Gn SGSN

  • No SGI Non-IP sup by peer MME

  • No SCEF Non-IP sup by peer MME

• Outbound Handover Denied (HO Prep Failure)

  • No SGI Non-IP sup by peer Node

  • No SCEF Non-IP sup by peer Node

• Outbound Relocation using S1HO/SRNS/PSHO - PDN Deactivation

  • No SGI Non-IP sup by peer S3 SGSN

  • No SCEF Non-IP sup by peer S3 SGSN

  • No SGI Non-IP sup by peer Gn SGSN

  • No SCEF Non-IP sup by peer Gn SGSN

  • No SGI Non-IP sup by peer MME

  • No SCEF Non-IP sup by peer MME

show mme-service session counters imsi imsi_number

The following new fields are added to the output of this command. These statistics are displayed only when CP CIoT optimization is enabled.

• ECM events:

  • UE Initiated CP Service Request Event

    • Attempted

    • Success

    • Failures

  • NW Initiated CP Service Request Events

    • Attempted

    • Success

    • Failures

• ESM events:

  • NON-IP PDN Connections to SCEF

    • Attempted

    • Success

    • Failures

  • NON-IP PDN Connections to SGI:

    • Attempted

    • Success

    • Failures

  • PDN Disconnections to SCEF:

    • Attempted

    • Success

    • Failures

  • Control Plane User Data Statistics:

    • Cumulative Data Over NAS Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Cumulative IP Data Over S11U Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Cumulative Non- IP Data Over S11U Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Cumulative Data Over T6A (SCEF) Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Per PDN Statistics

    • APN Name

    • Data Over NAS Statistics

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • IP Data Over S11U Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Non-IP Data Over S11U Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Data Over T6A (SCEF) Statistics:

      • Rx Packets

      • Rx Bytes

      • Tx Packets

      • Tx Bytes

      • Rx Drop Packets

      • Rx Drop Bytes

      • Tx Drop Packets

      • Tx Drop Bytes

    • Partially Ciphered messages

show session disconnect-reasons verbose

The following new statistics are added to the output of this command:

• mme-gtpu-path-failure-s11u

• mme-gtpu-err-ind-s11u

The following bulk statistics are added in the MME Schema in support of the Small Data over NAS, S11-U and SGi Interfaces feature.

The following disconnect reasons are added in support of the Small Data over NAS, S11-U and SGi Interfaces feature.

• mme-gtpu-path-failure-s11u: This disconnect reason is pegged when the session gets disconnected due to path failure on S11-U path between MME and S-GW.

• mme-gtpu-err-ind-s11u: This disconnect reason is pegged when the session gets disconnected due to GTP-U Error Indication received on S11-U interface on MME.

Diameter Attribute Value Pairs (AVPs) carry specific authentication, accounting, authorization, routing and security information as well as configuration details for the request and reply.

The following Diameter attributes are added in support of the Small Data over NAS, S11-U and SGi Interfaces feature.

Non-IP-PDN-Type-Indicator

This AVP indicates whether the APN has a Non-IP PDN type.

Vendor ID 10415

VSA Type 1681

AVP Type ENUM

AVP Flag V

Non-IP-Data-Delivery-Mechanism

This AVP indicates the mechanism to be used for Non-IP data delivery for a given APN.

Vendor ID 10415

VSA Type 1682

AVP Type UINT32

AVP Flag V

Additional-Context-Identifier

This AVP indicates the identity of another default APN to be used when the subscription profile of the user contains APNs with both IP-based and non-IP PDN types.

Vendor ID 10415

VSA Type 1683

AVP Type UINT32

AVP Flag V

The troubleshooting scenarios described in this section help in resolving minor issues related to incorrect configurations.

If the Control Plane CIoT optimization is not functioning as configured, use the following troubleshooting steps to resolve the issue:

1. Verify the ciot-optimisation command configuration.

2. Execute the show call-control-profile full name profile_name and show mme-service session full all commands to verify if the call-control profile criteria matches that of the UE.

3. Use the monitor subscriber CLI command to ensure that the UE supports and has requested for Control Plane optimization in NAS Attach or TAU messages.

4. Verify if the GTP-U service is configured correctly and is associated with the S11-U interface. See the sample configuration documented in this chapter.

5. Ensure that the current S-GW selected for the UE supports the S11-U interface.

If the PDN setup fails for PDN type non-IP, use the following troubleshooting steps to resolve the issue:

1. Execute the show mme-service db record imsi imsi_number command to verify if the non-IP PDN is present in the subscription provided by the HSS.

2. If the HSS provided subscription is missing or incorrect, add a non-IP PDN type by executing the pdn-type CLI command in the APN Profile Configuration mode.

3. Ensure that the P-GW serving the APN supports non-IP.

4. Ensure that the current S-GW selected for the UE supports non-IP.

If the PDN setup fails for PDN type non-IP, use the following troubleshooting steps to resolve the issue:

1. 1. Execute the show mme-service db record imsi imsi_number command to verify if the non-IP PDN is present in the subscription provided by the HSS.

2. Execute the show call-control-profile full name profile_name and show mme-service session full all commands to verify if the call-control profile criteria matches that of the UE.

3. Use the monitor subscriber CLI command to ensure that the UE supports and has requested for Control Plane optimization in NAS Attach or TAU messages.