Abstract:
A device receives, from an application server, a message destined for a user equipment, and reformats the message into a non-access stratum (NAS) transparent message. The device also provides, to a home subscriber server, a query for an identification of a mobility management entity serving the user equipment, and receives, from the home subscriber server, the identification of the mobility management entity serving the user equipment. The device further provides the NAS transparent message to the identified mobility management entity, where the mobility management entity forwards the NAS transparent message to the user equipment.

Description:
BACKGROUND 
     A fourth generation (4G) wireless network is an all Internet protocol (IP) wireless network in which different advanced multimedia application services (e.g., voice over IP (VoIP) content, video content, etc.) are delivered over IP. 4G wireless networks include a radio access network, such as, for example, a long term evolution (LTE) network or an enhanced high rate packet data (eHRPD) network. 4G wireless networks also include an IP multimedia subsystem (IMS) network and a wireless core network, referred to as an evolved packet core (EPC) network. The LTE network is often called an evolved universal terrestrial radio access network (E-UTRAN). The EPC network is an all-IP packet-switched core network that supports high-speed wireless and wireline broadband access technologies. An evolved packet system (EPS) is defined to include the LTE (or eHRPD) network and the EPC network. 
     Two components of the EPS are a home subscriber server (HSS) and a mobility management entity (MME). The HSS is provided in the IMS network and includes a database, which stores user equipment (UE) subscriber profile information. The MME is provided in the EPC network and is responsible for handling control plane signaling with UEs as the UEs are provided access to different packet data networks (PDNs). 
     Non-access stratum (NAS) is a highest stratum of a control plane between a UE and a MME. NAS protocols support mobility of the UE and further support session management procedures to establish and maintain IP connectivity between the UE and a packet data network (PDN) gateway (PGW). NAS protocols define rules for a mapping between parameters during inter-system mobility with third generation (3G) networks. NAS protocols also provide NAS security by integrity protection and ciphering of NAS signaling messages. To enable transfer of application protocol messages between the MME and the UE, NAS protocols define a generic container message on the downlink (e.g., a downlink generic NAS transport message) and define another generic container message on the uplink (e.g., an uplink generic NAS transport message). However, current networks do not fully utilize the capabilities of NAS messaging and are unable to exchange enough information via a typical IP transport. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagram of an example network in which systems and/or methods described herein may be implemented; 
         FIG. 2  is a diagram of example components of a device that may correspond to one of the devices of the network depicted in  FIG. 1 ; 
         FIG. 3  is a diagram of example operations capable of being performed by an example portion of the network in  FIG. 1 ; 
         FIG. 4  is a diagram of an example NAS generic container message type information element; 
         FIG. 5  is a diagram of an example modified NAS generic container message type information element capable of being generated by a short message service center (SMSC) of  FIG. 1 ; 
         FIG. 6  is a diagram of example functional components of the SMSC; and 
         FIG. 7  is a flow chart of an example process for providing NAS transparent messaging according to an implementation described herein. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     The following detailed description refers to the accompanying drawings. The same reference numbers in different drawings may identify the same or similar elements. 
     Systems and/or methods described herein may enable NAS transparent messages to be provided between a MME and a UE. Content of the NAS transparent messages may be transparent to the MME so that the MME may not need to decode and understand the content of the messages. The UE and a device (e.g., an application server) originating or receiving the NAS transparent message may agree on a format of the content. The NAS transparent message may include a flag to indicate a nature of the message and an application to which the message is to be sent. If the UE does not recognize the flag in the NAS transparent message, the UE may ignore the NAS transparent message. The NAS transparent messaging provided by the systems and/or methods may enable more information to be exchanged between a UE and a MME (or an application server) than may be permitted via a typical IP transport. 
     As used herein, the terms “subscriber” and/or “user” may be used interchangeably. Also, the terms “subscriber” and/or “user” are intended to be broadly interpreted to include a UE, or a user of a UE. 
     The term “component,” as used herein, is intended to be broadly construed to include hardware (e.g., a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a chip, a memory device (e.g., a read only memory (ROM), a random access memory (RAM), etc.), etc.) or a combination of hardware and software (e.g., a processor, microprocessor, ASIC, etc. executing software contained in a memory device). 
       FIG. 1  is a diagram of an example network  100  in which systems and/or methods described herein may be implemented. As illustrated, network  100  may include a UE  110 , a LTE network  120 , an EPC network  130 , an IMS network  140 , a PDN  150 , a short message service center (SMSC)  160 , and an application server (AS)  170 . LTE network  120  may include a base station or an eNodeB (eNB)  122 . EPC network  130  may include a MME  132 , a serving gateway (SGW)  134 , and a PDN gateway (PGW)  136 . IMS network  140  may include a HSS  142 . Devices and/or networks of network  100  may interconnect via wired and/or wireless connections. 
     A single UE  110 , LTE network  120 , eNB  122 , EPC network  130 , MME  132 , SGW  134 , PGW  136 , IMS network  140 , HSS  142 , PDN  150 , SMSC  160 , and application server  170  have been illustrated in  FIG. 1  for simplicity. In practice, there may be more UEs  110 , LTE networks  120 , eNBs  122 , EPC networks  130 , MMEs  132 , SGWs  134 , PGWs  136 , IMS networks  140 , HSSs  142 , PDNs  150 , SMSCs  160 , and/or application servers  170 . As further shown in  FIG. 1 , eNB  122  may interface with MME  132  over a S1-MME interface, and may interface with SGW  134  over a S1-U interface. MME  132  may interface with SGW  134  over a S11 interface, and may interface with HSS  142  over a S6a interface. SGW  134  may interface with PGW  136  over a S5 interface. PGW  136  may interface with PDN  150  over a SGi interface, and may interface with PCRF  160  over a Gx interface. 
     SMSC  160  may interface with HSS  142  over a Sh interface, and may interface with MME  132  over a V6a interface. The Sh interface may include all the features of a Diameter protocol Sh interface and may be enhanced to enable SMSC  160  to query HSS  142  for an identification of a MME (e.g., MME  132 ) serving UE  110 . The V6a interface may include an interface that complies with all Diameter protocol standard procedures. The V6a interface may enable the following example messages: a message-delivery-request (MDR) from SMSC  160  to MME  132 ; a message-delivery-answer (MDA) from MME  132  to SMSC  160  in response to a MDR; a message-submission-request (MSR) from MME  132  to SMSC  160 ; a message-submission-answer (MSA) from SMSC  160  to MME  132  in response to a MSR; etc. In one example, MME  132  may act as a Diameter client over the V6a interface, and SMSC  160  may act as a Diameter server over the V6a interface. MME  132  may utilize the V6a interface to relay NAS transparent messages between UE  110  and SMSC  160 . 
     UE  110  may include a radiotelephone, a personal communications system (PCS) terminal (e.g., that may combine a cellular radiotelephone with data processing and data communications capabilities), a wireless telephone, a cellular telephone, a smart phone, a personal digital assistant (PDA) (e.g., that can include a radiotelephone, a pager, Internet/intranet access, etc.), a laptop computer (e.g., with a wireless air card), or other types of computation and communication devices. In one example, UE  110  may include a device that is capable of communicating over LTE network  120 , EPC network  130 , IMS network  140 , and/or PDN  150 . 
     LTE network  120  may include a communications network that connects subscribers (e.g., UEs  110 ) to a service provider. In one example, LTE network  120  may include a WiFi network (e.g., using IEEE 802.11 standards) or other access networks (e.g., an E-UTRAN or an eHRPD network). In another example, LTE network  120  may include a radio access network capable of supporting high data rate, low latency, packet optimization, large capacity and coverage, etc. 
     eNB  122  may include one or more computation and communication devices that receive traffic (e.g., voice and/or data) from MME  132  and/or SGW  134  and wirelessly transmit that traffic to UE  110 . eNB  122  may also include one or more devices that wirelessly receive traffic from UE  110  and transmit that traffic to one of MME  132  and/or SGW  134  or to other UEs  110 . eNB  122  may combine the functionalities of a base station and a radio network controller (RNC) in second generation (2G) or 3G radio access networks. 
     EPC network  130  may include a core network architecture of the Third Generation Partnership Project (3GPP) LTE wireless communication standard. In one example, EPC network  130  may include an all-IP packet-switched core network that supports high-speed wireless and wireline broadband access technologies. In another example, EPC network  130  may provide packet-switched voice services (e.g., which are traditionally circuit-switched) using IMS network  140 . 
     MME  132  may include one or more computation and communication devices that may be responsible for idle mode tracking and paging procedures (e.g., including retransmissions) for UE  110 . MME  132  may be involved in a bearer activation/deactivation process (e.g., for UE  110 ) and may choose a SGW for UE  110  at an initial attach and at a time of intra-LTE handover. MME  132  may authenticate UE  110  via interaction with HSS  142 . MME  132  may generate and allocate temporary identities to UEs  110 . MME  132  may check authorization of UE  110  to camp on a service provider&#39;s Public Land Mobile Network (PLMN) and may enforce roaming restrictions for UE  110 . MME  132  may be a termination point in EPC network  130  for ciphering/integrity protection for NAS signaling and may handle security key management. MME  132  may provide a control plane function for mobility between LTE and access networks. 
     SGW  134  may include one or more traffic transfer devices (or network devices), such as a gateway, a router, a switch, a firewall, a network interface card (NIC), a hub, a bridge, a proxy server, an optical add-drop multiplexer (OADM), or some other type of device that processes and/or transfers traffic. In one example implementation, SGW  134  may route and forward user data packets, may act as a mobility anchor for a user plane during inter-eNB handovers, and may act as an anchor for mobility between LTE and other 3GPP technologies. For an idle state UE  110 , SGW  134  may terminate a downlink (DL) data path and may trigger paging when DL traffic arrives for UE  110 . SGW  134  may manage and store contexts (e.g., parameters of an IP bearer service, network internal routing information, etc.) associated with UE  110 . 
     PGW  136  may include one or more traffic transfer devices (or network devices), such as a gateway, a router, a switch, a firewall, a NIC, a hub, a bridge, a proxy server, an OADM, or some other type of device that processes and/or transfers traffic. In one example implementation, PGW  136  may provide connectivity of UE  110  to external PDNs (e.g., PDN  150 ) by being a traffic exit/entry point for UE  110 . UE  110  may simultaneously connect to more than one PGW  136  for accessing multiple PDNs  150 . PGW  136  may perform policy enforcement, packet filtering for each user, charging support, lawful intercept, and packet screening. PGW  136  may also act as an anchor for mobility between 3GPP and non-3GPP technologies. 
     IMS network  140  may include an architectural framework or network (e.g., a telecommunications network) for delivering IP multimedia services. 
     HSS  142  may include one or more computation and communication devices that gather, process, search, and/or provide information in a manner described herein. In one example implementation, HSS  142  may include a master user database that supports devices of IMS network  140  that handle calls. HSS  142  may include subscription-related information (e.g., subscriber profiles), may perform authentication and authorization of a user of UE  110 , and may provide information about UE  110 &#39;s location and IP information. In one example implementation, HSS  142  may store information identifying which MMEs (e.g., MME  132 ) are supporting which UEs (e.g., UE  110 ). 
     PDN  150  may include one or more networks, such as a local area network (LAN), a wide area network (WAN), a metropolitan area network (MAN), a telephone network, the Internet, etc., capable of facilitating communication with UE  110 . In one example, PDN  150  may include a network that breaks up a message (e.g., information) into packets for transmission. Unlike a circuit switching network, which requires establishment of a dedicated point-to-point connection, each packet in PDN  150  may include a destination address. Thus, packets in a single message may not travel the same path. As traffic conditions change in PDN  150 , the packets may be dynamically routed via different paths in PDN  150 , and the packets may even arrive out of order. A destination device in PDN  150  may reassemble the packets into their proper sequence. In one example implementation, PDN  150  may include multiple PDNs, such as a first PDN  150 - 1 , a second PDN  150 - 2 , etc., which may be accessed by UE  110 . 
     SMSC  160  may include one or more server devices, or other types of computation and communication devices, that gather, process, and/or provide information in a manner described herein. For example, SMSC  160  may be responsible for handling SMS operations of network  100 . When a SMS message is sent from UE  110 , SMSC  160  may receive the SMS message and may forward the SMS message towards a destination. If a recipient of the SMS message is unavailable (e.g., when a receiving UE  110  is turned off), SMSC  160  may store the SMS message. 
     SMSC  160  may support NAS transparent messages for applications associated with UE  110 . SMSC  160  may receive messages from application servers (e.g., application server  170 ) using protocols, such as the Short Message Peer-to-Peer (SMPP) protocol. SMSC  160  may reformat the messages received from the application servers into NAS transparent messages to be delivered to UE  110 . The Sh interface may enable SMSC  160  to query HSS  142  for an identification of a MME currently serving a UE to which SMSC  160  is delivering NAS transparent messages. The V6a may enable SMSC  160  to deliver NAS transparent messages to the identified MME that is currently serving the UE. 
     In one example implementation, SMSC  160  may receive, from application server  170 , a mobile terminated (MT) message for UE  110 , and may reformat the MT message into a NAS transparent message. SMSC  160  may query HSS  142  for an identification of a MME (e.g., MME  132 ) serving UE  110 , and may receive, from HSS  142  and based on the query, the identification of MME  132 . SMSC  160  may provide the NAS transparent message to the identified MME  132  (e.g., for providing to UE  110 ), and may receive, from MME  132 , a NAS transparent response generated by UE  110  in response to the NAS transparent message. SMSC  160  may then provide the NAS transparent response to application server  170 . 
     Application server  170  may include one or more server devices, or other types of computation and communication devices, that gather, process, and/or provide information in a manner described herein. For example, application server  170  may include a subscriber identity module (SIM) over-the-air (OTA) server that provides applications for a Universal Integrated Circuit Card (UICC), a SIM card, an OTA card, etc. provided in UE  110 . Alternatively, or additionally, application server  170  may include an open mobile alliance (OMA) device management (DM) server that provides applications for UE  110 , such as provisioning applications, device configuration applications, software upgrades, fault management applications, etc. 
     Although  FIG. 1  shows example devices/networks of network  100 , in other implementations, network  100  may include fewer devices/networks, different devices/networks, differently arranged devices/networks, or additional devices/networks than depicted in  FIG. 1 . Alternatively, or additionally, one or more devices/networks of network  100  may perform one or more other tasks described as being performed by one or more other devices/networks of network  100 . 
       FIG. 2  is a diagram of example components of a device  200  that may correspond to one of the devices of network  100 . In one example implementation, one or more of the devices of network  100  may include one or more devices  200 . As illustrated in  FIG. 2 , device  200  may include a bus  210 , a processing unit  220 , a memory  230 , an input device  240 , an output device  250 , and a communication interface  260 . 
     Bus  210  may permit communication among the components of device  200 . Processing unit  220  may include one or more processors or microprocessors that interpret and execute instructions. In other implementations, processing unit  220  may be implemented as or include one or more ASICs, FPGAs, or the like. 
     Memory  230  may include a RAM or another type of dynamic storage device that stores information and instructions for execution by processing unit  220 , a ROM or another type of static storage device that stores static information and instructions for the processing unit  220 , and/or some other type of magnetic or optical recording medium and its corresponding drive for storing information and/or instructions. 
     Input device  240  may include a device that permits an operator to input information to device  200 , such as a keyboard, a keypad, a mouse, a pen, a microphone, one or more biometric mechanisms, and the like. Output device  250  may include a device that outputs information to the operator, such as a display, a speaker, etc. 
     Communication interface  260  may include any transceiver-like mechanism that enables device  200  to communicate with other devices and/or systems. For example, communication interface  260  may include mechanisms for communicating with other devices, such as other devices of network  100 . 
     As described herein, device  200  may perform certain operations in response to processing unit  220  executing software instructions contained in a computer-readable medium, such as memory  230 . A computer-readable medium may be defined as a non-transitory memory device. A memory device may include space within a single physical memory device or spread across multiple physical memory devices. The software instructions may be read into memory  230  from another computer-readable medium or from another device via communication interface  260 . The software instructions contained in memory  230  may cause processing unit  220  to perform processes described herein. Alternatively, or additionally, hardwired circuitry may be used in place of or in combination with software instructions to implement processes described herein. Thus, implementations described herein are not limited to any specific combination of hardware circuitry and software. 
     Although  FIG. 2  shows example components of device  200 , in other implementations, device  200  may include fewer components, different components, differently arranged components, or additional components than depicted in  FIG. 2 . Alternatively, or additionally, one or more components of device  200  may perform one or more other tasks described as being performed by one or more other components of device  200 . 
       FIG. 3  is a diagram of example operations capable of being performed by an example network portion  300  of network  100  ( FIG. 1 ). As shown in  FIG. 3 , network portion  300  may include UE  110 , MME  132 , HSS  142 , SMSC  160 , and application server  170 . UE  110 , MME  132 , HSS  142 , SMSC  160 , and application server  170  may include the features described above in connection with, for example, one or more of  FIGS. 1 and 2 . 
     As further shown in  FIG. 3 , application server  170  may provide a message  310  to SMSC  160  by using a protocol, such as the SMPP protocol. In one example, message  310  may include a mobile terminated (MT) message (e.g., a network triggered message to an application client of UE  110 ) to be provided to UE  110 ; a SIM OTA message (e.g., that includes SIM OTA client wake-up information) that instructs a SIM OTA client of a UICC of UE  110  to poll network  100  for additional information; a OMA DM message (e.g., that includes OMA DM client wake-up information) that instructs a OMA DM client of UE  110  to poll network  100  for additional information; etc. Alternatively, or additionally, message  310  may include a short command message for applications provided in UE  110 , the UICC, or other secondary devices associated with UE  110  (e.g., a secure digital (SD) memory card). SMSC  160  may receive message  310  from application server  170 , and may, based on message  310 , provide a query  320  to HSS  142  via the Sh interface (not shown in  FIG. 3 ). Query  320  may include a request for an identification of a MME serving UE  110 . HSS  142  may retrieve an identification  330  of MME  132  based on query  320 , and may provide identification  330  of MME  132  to SMSC  160 . 
     SMSC  160  may receive identification  330  of MME  132  from HSS  142 . SMSC  160  may reformat message  310  into a NAS transparent message  340 . Content of NAS transparent message  340  may be transparent to MME  132  so that MME  132  may not need to decode and understand the content of NAS transparent message  340 . UE  110  and application server  170  may agree on a format of the content of NAS transparent message  340 . NAS transparent message  340  may include a flag to indicate a nature of the message and an application of UE  110  to which the message is to be sent. SMSC  160  may provide NAS transparent message  340  to MME  132  identified by identification  330  and via the V6a interface (not shown in  FIG. 3 ). 
     MME  132  may receive NAS transparent message  340 , and may forward NAS transparent message  340  to UE  110 . UE  110  may receive NAS transparent message  340 , and may analyze the flag in NAS transparent message  340 . If UE  110  does not recognize the flag in NAS transparent message  340 , UE  110  may ignore NAS transparent message  340 . If UE  110  recognizes the flag in NAS transparent message  340 , UE  110  may analyze an identifier in NAS transparent message  340  to determine a purpose of NAS transparent message  340 . For example, if NAS transparent message  340  is for a UICC of UE  110 , then UE  110  may utilize NAS transparent message  340  for the UICC. As further shown in  FIG. 3 , UE  110  may provide, to MME  132 , a NAS transparent response  350  that responds to NAS transparent message  340 . MME  132  may forward NAS transparent response  350  to SMSC  160 , and SMSC  160  may receive NAS transparent response  350 . SMSC  160  may forward NAS transparent response  350  to application server  170 , and application server  170  may communicate with UE  110  (e.g., via mechanisms other than NAS messages) based on NAS transparent response  350 . In one example, NAS transparent response  350  may be omitted and/or replaced with an ordinary (i.e., non-NAS transparent) response. 
     In one example implementation, SMSC  160  may enable more information (e.g., message  310 , NAS transparent message  340 , and NAS transparent response  350 ) to be exchanged between UE  110  and application server  170  than may be permitted via a typical IP transport. In one example, NAS transparent message  340  may include a downlink generic NAS transport message according to the following format (e.g., as defined in 3GPP Technical Specification (TS) 24.301). 
     
       
         
               
               
               
               
               
             
           
               
                   
               
               
                 Information Element 
                 Type 
                 Presence 
                 Format 
                 Length 
               
               
                   
               
             
             
               
                 Protocol discriminator 
                 Protocol discriminator 
                 M 
                 V 
                 ½ 
               
               
                   
                 9.2 
                   
                   
                   
               
               
                 Security header type 
                 Security header type 
                 M 
                 V 
                 ½ 
               
               
                   
                 9.3.1 
                   
                   
                   
               
               
                 Downlink generic NAS transport 
                 Message type 
                 M 
                 V 
                 1 
               
               
                 message identity 
                 9.8 
                   
                   
                   
               
               
                 Generic message container type 
                 Generic message container type 
                 M 
                 V 
                 1 
               
               
                   
                 9.9.3.42 
                   
                   
                   
               
               
                 Generic message container 
                 Generic message container 
                 M 
                 LV-E 
                 3-n 
               
               
                   
                 9.9.3.43 
                   
                   
                   
               
               
                 Additional information 
                 Additional information 
                 O 
                 TLV 
                 3-n 
               
               
                   
                 9.9.2.0 
               
               
                   
               
             
          
         
       
     
     As shown, NAS transparent message  340  may include information elements (e.g., a generic message container type, described below in  FIGS. 4 and 5 ), types (e.g., a generic message container type), a presence, a format, and a length. In one example, NAS transparent response  350  may include an uplink generic NAS transport message according to the following format (e.g., as defined in 3GPP TS 24.301). 
     
       
         
               
               
               
               
               
             
           
               
                   
               
               
                 Information Element 
                 Type 
                 Presence 
                 Format 
                 Length 
               
               
                   
               
             
             
               
                 Protocol discriminator 
                 Protocol discriminator 
                 M 
                 V 
                 ½ 
               
               
                   
                 9.2 
                   
                   
                   
               
               
                 Security header type 
                 Security header type 
                 M 
                 V 
                 ½ 
               
               
                   
                 9.3.1 
                   
                   
                   
               
               
                 Uplink generic NAS transport 
                 Message type 
                 M 
                 V 
                 1 
               
               
                 message identity 
                 9.8 
                   
                   
                   
               
               
                 Generic message container type 
                 Generic message container type 
                 M 
                 V 
                 1 
               
               
                   
                 9.9.3.42 
                   
                   
                   
               
               
                 Generic message container 
                 Generic message container 
                 M 
                 LV-E 
                 3-n 
               
               
                   
                 9.9.3.43 
                   
                   
                   
               
               
                 Additional information 
                 Additional information 
                 O 
                 TLV 
                 3-n 
               
               
                   
                 9.9.2.0 
               
               
                   
               
             
          
         
       
     
     Although  FIG. 3  show example components of network portion  300 , in other implementations, network portion  300  may include fewer components, different components, differently arranged components, or additional components than depicted in  FIG. 3 . Additionally, or alternatively, one or more components of network portion  300  may perform one or more other tasks described as being performed by one or more other components of network portion  300 . For example, although application server  170  is shown as generating an initial message  310 , in other implementations, UE  110  may generate an initial message, such as a UE  110 , UICC, or SD memory card triggered message to inform network  100  of particular events. 
       FIG. 4  is a diagram of an example NAS generic container message type information element  400  as defined in 3GPP TS 24.301 (e.g., in the fourth information element of the above mentioned tables). As shown, information element  400  may include ranges of bits  410  that may be assigned to different functions. For example, bits  410  (0, 0, 0, 0, 0, 0, 0, 0) through (0, 0, 0, 0, 0, 0, 1, 0) may be assigned to certain functions  420 , such as reserved, a LTE positioning protocol (LPP), and a location services message container. Bits  410  (0, 0, 0, 0, 0, 0, 1, 1) through (0, 1, 1, 1, 1, 1, 1, 1) may be unused, as indicated by reference number  430 . Bits  410  (1, 0, 0, 0, 0, 0, 0, 0) through (1, 1, 1, 1, 1, 1, 1, 1) may be reserved, as indicated by reference number  440 . 
     Although  FIG. 4  show example information that may be provided in information element  400 , in other implementations, information element  400  may include less information, different information, differently arranged information, or additional information than depicted in  FIG. 4 . 
       FIG. 5  is a diagram of an example modified NAS generic container message type information element  500  capable of being generated by a SMSC  160 . Information element  500  may include a modified version of NAS generic container message type information element  400  as defined in 3GPP TS 24.301. In one example implementation, information element  500  may be included in message  310  to reformat message  310  into NAS transparent message  340 . 
     As shown in  FIG. 5 , information element  500  may include the ranges of bits  410  and associated functions described above for information element  400  ( FIG. 4 ). For example, bits  410  (0, 0, 0, 0, 0, 0, 0, 0) through (0, 0, 0, 0, 0, 0, 1, 0) may be assigned to certain functions  420 , such as reserved, a LTE positioning protocol (LPP), and a location services message container. Bits  410  (0, a, b, c, d, e, f, 1) through (0, 1, 1, 1, 1, 1, 1, 1) may be unused, as indicated by reference number  430 . Bits  410  (1, 0, 0, 0, 0, 0, 0, 0) through (1, 1, 1, 1, 1, 1, 1, 1) may be reserved, as indicated by reference number  440 . 
     As further shown in  FIG. 5 , information element  500  may include additional ranges of bits  510  that may be assigned to different functions. For example, bits  510  (0, 0, 0, 0, 0, 0, 1, 1) may be used for a SIM OTA message container  520 , and bits  510  (0, 0, 0, 0, 0, 1, 0, 0) may be used for an OMA DM message container  530 . Bits  510  (0, 0, 0, 0, 0, 1, 0, 1) through (0, a, b, c, d, e, f, 0) may be operator specific, as indicated by reference number  540 . In one example bits  510  (0, a, b, c, d, e, f, 0) may be greater than bits  510  (0, 0, 0, 0, 0, 1, 0, 1), and bits  410  ( 0 , a, b, c, d, e, f, 1) may be greater than or equal to bits  410  (0, 1, 1, 1, 1, 1, 1, 1). 
     Although  FIG. 5  shows example information that may be provided in information element  500 , in other implementations, information element  500  may contain less information, different information, differently arranged information, and/or additional information than depicted in  FIG. 5 . 
       FIG. 6  is a diagram of example functional components of SMSC  160 . In one implementation, the functions described in connection with  FIG. 6  may be performed by one or more components of device  200  ( FIG. 2 ) or by one or more devices  200 . As shown in  FIG. 6 , SMSC  160  may include a message reformatting component  600 , a MME identifying component  610 , and a message forwarding component  620 . 
     Message reformatting component  600  may receive message  310  from application server  170  (not shown in  FIG. 6 ), and may reformat message  310  into NAS transparent message  340 . In one example, message reformatting component  600  may reformat message  310  to include modified NAS generic container message type information element  500  ( FIG. 5 ) in NAS transparent message  340 . As further shown in  FIG. 6 , message reformatting component  600  may provide NAS transparent message  340  to message forwarding component  620 . 
     MME identifying component  610  may, based on message  310 , provide query  320  to HSS  142  (not shown in  FIG. 6 ). Based on query  320 , MME identifying component  610  may receive identification  330  of MME  132  from HSS  142 . As further shown in  FIG. 6 , MME identifying component  610  may provide identification  330  of MME  132  to message forwarding component  620 . 
     Message forwarding component  620  may receive NAS transparent message  340  from message reformatting component  600 , and may receive identification  330  of MME  132  from MME identifying component  610 . Based on identification  330 , message forwarding component  620  may forward NAS transparent message  340  to MME  132  (not shown in  FIG. 6 ). As further shown in  FIG. 6 , message forwarding component  620  may receive NAS transparent response  350  from MME  132  (not shown in  FIG. 6 ), and may forward NAS transparent response  350  to application server  170  (not shown in  FIG. 6 ). 
     Although  FIG. 6  shows example functional components of SMSC  160 , in other implementations, SMSC  160  may include fewer functional components, different functional components, differently arranged functional components, or additional functional components than depicted in  FIG. 6 . Alternatively, or additionally, one or more functional components of SMSC  160  may perform one or more other tasks described as being performed by one or more other functional components of SMSC  160 . 
       FIG. 7  is a flow chart of an example process  700  for providing NAS transparent messaging according to an implementation described herein. In one implementation, process  700  may be performed by SMSC  160 . Alternatively, or additionally, some or all of process  700  may be performed by another device or group of devices, including or excluding SMSC  160 . 
     As shown in  FIG. 7 , process  700  may include receiving, from an application server, a mobile terminated (MT) message for a UE (block  710 ), and reformatting the message into a NAS transparent message (block  720 ). For example, in an implementation described above in connection with  FIG. 3 , application server  170  may provide message  310  to SMSC  160  by using a protocol, such as the SMPP protocol. In one example, message  310  may include a mobile terminated (MT) message (e.g., a network triggered message to an application client of UE  110 ) to be provided to UE  110 . SMSC  160  may receive message  310  from application server  170 , and may reformat message  310  into NAS transparent message  340 . Content of NAS transparent message  340  may be transparent to MME  132  so that MME  132  may not need to decode and understand the content of NAS transparent message  340 . UE  110  and application server  170  may agree on a format of the content of NAS transparent message  340 . NAS transparent message  340  may include a flag to indicate a nature of the message and an application of UE  110  to which the message is to be sent. 
     As further shown in  FIG. 7 , process  700  may include querying a HSS for an identification of a MME serving the UE (block  730 ), and receiving, from the HSS and based on the query, an identification of a MME serving the UE (block  740 ). For example, in an implementation described above in connection with  FIG. 3 , based on message  310 , SMSC  160  may provide query  320  to HSS  142  via the Sh interface. Query  320  may include a request for an identification of a MME serving UE  110 . HSS  142  may retrieve identification  330  of MME  132  based on query  320 , and may provide identification  330  of MME  132  to SMSC  160 . SMSC  160  may receive identification  330  of MME  132  from HSS  142 . 
     Returning to  FIG. 7 , process  700  may include providing the NAS transparent message to the identified MME for providing to the UE (block  750 ), and receiving, from the identified MME, a NAS transparent response generated by the UE in response to the NAS transparent message (block  760 ). For example, in an implementation described above in connection with  FIG. 3 , SMSC  160  may provide NAS transparent message  340  to MME  132  identified by identification  330  and via the V6a interface. MME  132  may receive NAS transparent message  340 , and may forward NAS transparent message  340  to UE  110 . UE  110  may receive NAS transparent message  340 , and may analyze the flag in NAS transparent message  340 . If UE  110  recognizes the flag in NAS transparent message  340 , UE  110  may analyze an identifier in NAS transparent message  340  to determine a purpose of NAS transparent message  340 . UE  110  may provide, to MME  132 , NAS transparent response  350  that responds to NAS transparent message  340 . MME  132  may forward NAS transparent response  350  to SMSC  160 , and SMSC  160  may receive NAS transparent response  350 . 
     As further shown in  FIG. 7 , process  700  may include providing the NAS transparent response to the application server (block  770 ). For example, in an implementation described above in connection with  FIG. 3 , SMSC  160  may forward NAS transparent response  350  to application server  170 , and application server  170  may communicate with UE  110  (e.g., via mechanisms other than NAS messages) based on NAS transparent response  350 . 
     Systems and/or methods described herein may enable NAS transparent messages to be provided between a MME and a UE. Content of the NAS transparent messages may be transparent to the MME so that the MME may not need to decode and understand the content of the messages. The UE and a device (e.g., an application server) originating or receiving the NAS transparent message may agree on a format of the content. The NAS transparent message may include a flag to indicate a nature of the message and an application to which the message is to be sent. If the UE does not recognize the flag in the NAS transparent message, the UE may ignore the NAS transparent message. The NAS transparent messaging provided by the systems and/or methods may enable more information to be exchanged between a UE and a MME (or an application server) than may be permitted via a typical IP transport. 
     Furthermore, while a series of blocks has been described with regard to  FIG. 7 , the order of the blocks may be modified in other implementations. Further, non-dependent blocks may be performed in parallel. 
     It will be apparent that example aspects, as described above, may be implemented in many different forms of software, firmware, and hardware in the implementations illustrated in the figures. The actual software code or specialized control hardware used to implement these aspects should not be construed as limiting. Thus, the operation and behavior of the aspects were described without reference to the specific software code—it being understood that software and control hardware could be designed to implement the aspects based on the description herein. 
     Even though particular combinations of features are recited in the claims and/or disclosed in the specification, these combinations are not intended to limit the disclosure of the invention. In fact, many of these features may be combined in ways not specifically recited in the claims and/or disclosed in the specification. Although each dependent claim listed below may directly depend on only one other claim, the disclosure of the invention includes each dependent claim in combination with every other claim in the claim set. 
     No element, act, or instruction used in the present application should be construed as critical or essential to the invention unless explicitly described as such. Also, as used herein, the article “a” is intended to include one or more items. Where only one item is intended, the term “one” or similar language is used. Further, the phrase “based on” is intended to mean “based, at least in part, on” unless explicitly stated otherwise.