Abstract:
The present invention discloses a method and apparatus for a mobile station application to receive and transmit raw packetized data in a wireless communication system. The present invention includes a mobile station application that creates at least one socket. At least one of mobile station protocol layers of a communication protocol stack receives encapsulated raw packetized data from a communication network. The raw packetized data lacks destination port information. At least one of the mobile station protocol layers transmits unencapsulated raw packetized data to the created sockets. In turn, the created sockets transmit the raw packetized data to the mobile station application. In another implementation, the created sockets transmit raw packetized data of the mobile station application to at least one of the mobile station protocol layers. In turn, at least one of the mobile station protocol layers transmits encapsulated raw packetized data to the communication network.

Description:
BACKGROUND 
   1. Field of the Invention 
   This invention generally relates to the field of wireless communications. More particularly, the present invention relates to a novel method and apparatus for a mobile station application to receive and transmit raw packetized data in a wireless communication system. 
   2. Description of Related Art 
   A. Wireless Communications 
   Recent innovations in wireless communication and computer-related technologies, as well as the unprecedented growth of Internet subscribers, have paved the way for mobile computing. In fact, the popularity of mobile computing has placed greater demands on the current Internet infrastructure to provide mobile users with more support. The life blood of this infrastructure is the packet-oriented Internet Protocol (IP) which provides various services, including the addressing and routing of packets (datagrams) between local and wide area networks (LANs and WANs). IP protocol is defined in Request For Comment 791 (RFC 791) entitled, “INTERNET PROTOCOL DARPA INTERNET PROGRAM PROTOCOL SPECIFICATION,” dated September 1981. 
   The IP protocol is a network layer protocol that encapsulates data into IP packets for transmission. Addressing and routing information is affixed to the header of the packet. IP headers, for example, contain 32-bit addresses that identify the sending and receiving hosts. These addresses are used by intermediate routers to select a path through the network for the packet towards its ultimate destination at the intended address. Thus, the IP protocol allows packets originating at any Internet node in the world to be routed to any other Internet node in the world. On the other hand, a transport layer, which comprises either a Transmission Control Protocol (TCP) or a User Datagram Protocol (UDP), is used to address to particular applications. 
   The current trend is for mobile users to use mobile computers, such as laptop or palmtop computers, in conjunction with wireless communication devices, such as cellular or portable phones, to access the Internet. That is, just as users conventionally employ “wired” communication devices to connect their computers to land-based networks, mobile users will use wireless communication devices, commonly referred to as “mobile stations” (MSs), to connect their mobile terminals to such networks. As used herein, the mobile station or MS will refer to any subscriber station in the public wireless radio network. 
     FIG. 1  (Prior Art) illustrates a high-level block diagram of a wireless data communication system in which the MS  110  communicates with an Interworking Function (IWF)  108  via a Base Station/Mobile Switching Center (BS/MSC)  106 . The IWF  108  serves as the access point to the Internet. IWF  108  is coupled to, and often co-located with, BS/MSC  106 , which may be a conventional wireless base station as is known in the art. Another standard protocol that addresses the wireless data communication system is the 3 rd  Generation Partnership Project 2 (“3GPP2”) entitled “WIRELESS IP NETWORK STANDARD,” published in December 1999. The 3G Wireless IP Network Standard, for example, includes a Packet Data Serving Node (“PDSN”), which functions like the IWF  108 . 
   There are various protocols that address the data communications between the MS  110  and the IWF  108 . For example, Telecommunications Industry Association (TIA)/Electronics Industries Association (EIA) Interim Standard IS-95, entitled “MOBILE STATION-BASE STATION COMPATIBILITY STANDARD FOR DUAL-MODE WIDEBAND SPREAD SPECTRUM CELLULAR SYSTEM,” published in July 1993, generally provides a standard for wideband spread spectrum wireless communication systems. Moreover, standard TIA/EIA IS-707.5, entitled “DATA SERVICE OPTIONS SERVICES,” published in February 1998, defines requirements for support of packet data transmission capability on TIA/EIA IS- 95  systems and specifies packet data bearer services that may be used for communication between the MS  110  and the IWF  108  via the BS/MSC  106 . Also, the TIA/EIA IS- 707 -A.5 standard, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: PACKET DATA SERVICES,” and the TIA/EIA IS- 707 -A.9 standard, entitled “DATA SERVICE OPTIONS FOR SPREAD SPECTRUM SYSTEMS: HIGH-SPEED PACKET DATA SERVICES,” both published in March 1999, also define requirements for packet data transmission support on TIA/EIA IS-95 systems. In addition, another standard protocol that addresses communications between the MS  110  and the IWF  108  is the TIA/EIA IS-2000, entitled “INTRODUCTION TO CDMA 2000 STANDARDS FOR SPREAD SPECTRUM SYSTEMS,” published in July 1999. 
   IS-707.5 introduces communication protocol option models between the MS  110  and the BS/MSC  106  (the Um interface), and between the BS/MSC  106  and the IWF  108  (the L interface). For instance, a Relay Model represents the situation where a Point to Point Protocol (PPP) link exists on the Um interface between the MS  110  and the IWF  108 . The PPP protocol is described in detail in Request for Comments 1661 (RFC 1661), entitled “THE POINT-TO-POINT PROTOCOL (PPP).” 
     FIG. 2  (Prior Art) is a diagram of the protocol stacks in each entity of the IS-707.5 Relay Model. At the far left of the figure is a communication protocol stack, shown in conventional vertical format, showing the protocol layers running on the MS  110 . The MS  110  protocol stack is illustrated as being logically connected to the BS/MSC  106  protocol stack over the Um interface. The BS/MSC  106  protocol stack is, in turn, illustrated as being logically connected to the IWF  108  protocol stack over the L interface. 
   The operation depicted in  FIG. 2  is as follows: an upper layer protocol  200  entity, such as an application program running on the MS  110 , has a need to send data over the Internet. A representative application may be a web browser program (e.g., Netscape Navigator™, Microsoft Internet Explorer™). The web browser requests a Universal Resource Locator (URL), such as HYPERLINK “http://www.Qualcomm.com/”. A Domain Name System (DNS) protocol, also in the upper layer protocol  200 , translates the textual host name www.Qualcomm.com to a 32-bit numeric IP address by the use of a domain name resolution, which translates names to addresses in the Internet. The Hypertext Transfer Protocol (HTTP), which is also an upper layer protocol  200 , constructs a GET message for the requested URL, and specifies that TCP will be used to send the message and for HTTP operations. The transport layer  202  uses port  80 , which is known in the art, as the destination port to route the HTTP operations to the application. 
   The TCP protocol, which is a transport layer protocol  202 , opens a connection to the IP address specified by DNS and transmits the application-level HTTP GET message. The TCP protocol specifies that the IP protocol will be used for message transport. The IP protocol, which is a network layer protocol  204 , transmits the TCP packets to the IP address specified. The PPP, which is a link layer protocol  206 , encodes the IP packets and transmits them to the relay layer protocol  208 . An example of the relay layer protocol  208  may be the illustrated TIA/EIA-232F standard, which is defined in “INTERFACE BETWEEN DATA TERMINAL EQUIPMENT AND DATA CIRCUIT-TERMINATING EQUIPMENT EMPLOYING SERIAL BINARY DATA INTERCHANGE,” published in October 1997. It is to be understood that other standards or protocols known to artisans of ordinary skill in the art may be used to define the transmission across the layers. For example, other applicable standards may include the “UNIVERSAL SERIAL BUS (USB) SPECIFICATION, Revision 1.1,” published in September 1998, and the “BLUETOOTH SPECIFICATION VERSION 1.0A CORE,” published in July 1999. Last, the relay layer protocol  208  passes the PPP packets to a Radio Link Protocol (RLP)  210  and then to the IS-95 protocol  212  for transmission to the BS/MSC  106  over the Um interface. The RLP protocol  210  is defined in the IS-707.2 standard, entitled “DATA SERVICE OPTIONS FOR WIDEBAND SPREAD SPECTRUM SYSTEMS: RADIO LINK PROTOCOL,” published in February 1998, and the IS-95 protocol is defined in the IS-95 standard identified above. 
   A complementary relay layer protocol  220  on the BS/MSC  106  receives the PPP packets over the Um interface through a IS-95 layer  218  and then a RLP layer  216 . The relay layer protocol  220  passes them over the L interface to a relay layer protocol  228  on the IWF  108 . A PPP protocol link layer  226  on the IWF  108  receives the PPP packets from the relay layer protocol  228 , and terminates the PPP connection between the MS  110  and the IWF  108 . The packets are passed from the PPP layer  226  to a IP layer  224  on the IWF  108  for examination of the IP packet header for final routing, which in this scenario is www.Qualcomm.com. 
   Assuming that the ultimate destination of the IP packets generated by the MS  110  is not the IWF  108 , the packets are forwarded through the network layer protocols  224 , and link layer protocols  225  to the next router (not shown) on the Internet. In this manner, IP packets from the MS  110  are communicated through the BS/MSC  106 , and the IWF  108  towards their ultimate intended destination in the Internet in accordance with the IS-707.5 standard relay model. 
   Before the MS  110  packets reach their destination, the data link connection must be established first. As specified in RFC  1661 , this requires each end of the point-to-point link (i.e., the PPP protocols  206  and  226 ) to first send PPP Link Control Protocol (LCP) packets in order to establish, configure and test the data link connection. After the link has been established by the LCP, the PPP protocol  206  may then send Network Control Protocol (NCP) packets to configure the network layer protocols  204  and  224 . The NCP for IP in PPP links is the IP Control Protocol (IPCP). IPCP is described in detail in Request for Comment  1332  (RFC 1332), entitled “THE PPP INTERNET PROTOCOL CONTROL PROTOCOL (IPCP),” published in May 1992. Before IPCP negotiation, however, an authentication phase may be needed. After each of the network layer protocols has been configured, packets from each network layer protocol can be sent over the link between them. 
   B. Application Program Interface 
   Most, if not all, of the processes supporting the communication protocol stack on the MS  110  are executed by application programs. Generally, conventional data networks employ application program interfaces (APIs) to enable application programs running on one computer to communicate with application programs running on another computer. The APIs utilize “sockets,” which shelter the invoking applications from differences in the protocols of the underlying network. To achieve inter-networked communications, APIs comprise functions, which allow the applications, for example, to open a socket, transmit data to the network, receive data from the network, and close the socket. Common network programming interfaces include Berkeley Systems Development (BSD) sockets interface, which operates under a Unix™ operating system, and Windows™ Sockets Interface (WinSock™), which operates under a Windows™ operating system. 
   Because neither BSD sockets nor WinSock™ supports the communication protocol stack on the wireless MS  110  (see FIG.  2 ), a novel API supporting such a stack is needed. In particular, what is needed is a novel method and apparatus for a mobile station application to receive and transmit raw packetized data in a wireless communication system. 
   SUMMARY OF THE INVENTION 
   The present invention addresses the need identified above by providing a method and apparatus for a mobile station application to receive and transmit raw packetized data in a wireless communication system. In one implementation, a mobile station application creates at least one socket. At least one of mobile station protocol layers receives encapsulated raw packetized data, which lacks destination port information, from a communication network. At least one of the mobile station protocol layers transmits unencapsulated raw packetized data to the at least one socket. In turn, the at least one socket transmits the raw packetized data to the mobile station application. In another implementation, the at least one socket transmits raw packetized data of the mobile station application to at least one of the mobile station protocol layers. In turn, at least one of the mobile station protocol layers transmits encapsulated raw packetized data to the communication network. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  (Prior Art) is a high level block diagram of a wireless communication system in which a mobile station connects to the Internet. 
       FIG. 2  (Prior Art) schematically describes the protocol stacks in each entity of the TIA/EIA IS-707.5 Relay Model. 
       FIG. 3  schematically depicts features of an embodiment of the present invention. 
       FIGS. 4 and 5  are flow charts for detecting a specified event. 
       FIG. 6  is a block diagram depicting an asynchronous connection. 
       FIG. 7  is a block diagram depicting an asynchronous socket input. 
       FIGS. 8-10  are state diagrams of embodiments of the present invention. 
   

   DETAILED DESCRIPTION 
   The embodiments of the present invention may be realized in a variety of implementations, including software, firmware, and/or hardware. Hence, the operation and behavior of the present invention will be described without specific reference to the software code or hardware components, it being understood that a person of ordinary skill in the art would be able to design software and/or hardware to implement the present invention, which enables a mobile station application to receive and transmit raw packetized data, based on the description herein. 
     FIG. 3  depicts an application  260 , a communication protocol stack  280 , and an API  270  within a MS  110 . Application  260  and communication protocol stack  280  (i.e., protocol layers  202 ,  204 ,  206 ,  208 ,  210 ,  212 ) communicate through function calls, which are provided by API  270 . In other words, API  270  allows application  260  and communication protocol stack  280  to run on different processors and operating systems without compromising functionality. One skilled in the art would appreciate that various names for the invoked functions are possible without departing from the scope of the present invention. 
   It should be noted that communication protocol stack  280  contains a plurality of send queues and receive queues, which store data. Output functions read data from a memory of application  260  to store the data into one of the send queues of communication protocol stack  280 . Input functions read data from one of the receive queues of communication protocol stack  280  to store the data into the memory of application  260 . 
   To illustrate operation, the MS  110  receives IP packets. The communication protocol stack  280  of the MS  110  unencapsulates the IP packets, and passes them to the transport layer  202  (see FIG.  3 ). A field in the IP packet header indicates the transport, which may be either TCP or UDP. Based on the destination port number specified in the transport layer header, the data is routed to the appropriate receive queue of communication protocol stack  280 , which corresponds to a particular socket. The data may then be transmitted to application  260 . 
   In certain situations, it may be desirable to operate with packets that bypass various layers of the protocol stack  280  to reduce latency effects. Such packets include raw packetized data, such as raw IP packets, which lack destination information (i.e., destination port number). As such, the destination application may not be determined from the raw IP packets. In such situations, communication protocol stack  280  may transmit the received raw IP packets to all sockets registered to support the IP protocol, for example. This allows the payload data to be transmitted to the destination application. An Internet Control Messaging Protocol (ICMP) parsing engine, which responds to IP packets, may also receive the raw packetized data. The well-known ICMP parsing engine is defined in RFC 792, entitled “INTERNET CONTROL MESSAGE PROTOCOL.” It should be apparent from this description that communication protocol stack  280 , for example, processes the received packets before it passes them up the stack to application  260 , which reduces the amount of unencapsulation to be done by application  260 . 
   Conversely, application  260  may transmit raw packetized data over the Um interface by using the sockets, which facilitates communications between communication protocol stack  280  and application  260 . Further, application  260  may transmit raw packetized data over the Um interface. In turn, communication protocol stack  280  encapsulates the packetized or raw packetized data, for example, into IP packets and transmits them over the Um interface. In this example, communication protocol stack  280  provides a IP header and a checksum in order to generate the IP packets. For ICMP, on the other hand, a specified protocol type may be copied into the IP header. 
   As stated above, application  260  may create a socket that allows data communications between at least one of the protocol layers  202 ,  204 ,  206 ,  208 ,  210 ,  212  and application  260  to reduce the latency inherent in the use of communication protocol stack  280 . That is, application  260  may create a socket that bypasses the transport layer  202 , the network layer  204 , and the link layer  206 , and thus allows application  260  to transmit payload data to, or receive payload data from, the RLP layer  210 . Also, application  260  may create a socket that allows application  260  to transmit payload data to, or receive payload data from, the IS- 95  layer  212 . 
   In one embodiment, application  260  calls a function open_netlib ( ) to open communication protocol stack  280  and to assign an application identification. The application identification allows multiple applications to communicate with communication protocol stack  280  (i.e., multi-tasking). As part of the call to function open_netlib ( ), for example, application  260  specifies a pointer to a network callback function and to a socket callback function. The network callback function is invoked to inform application  260  whenever network subsystem specified events, such as read from, write to, and close the traffic channel (i.e., Um) and/or a link-layer (i.e., PPP  206 ), have occurred (or have been enabled). The socket callback function is invoked to inform application  260  whenever socket specified events, such as read from, write to and close the transport layer (i.e., TCP), have occurred (or have been enabled). It should be apparent to one skilled in the art that a communication network comprises at least one of the traffic channel, the link-layer, and the transport layer. 
   Once communication protocol stack  280  has been opened, a function pppopen ( ) is called to initiate a network subsystem connection, which includes the traffic channel and the link-layer. This is an application-wide call, which is not dependent on an individual socket. It, however, requires the application identification. Upon the establishment or failure of the network subsystem connection, the network callback function is invoked to provide a specified event notification. The network subsystem fails, for example, if the traffic channel is not established. Further, the network subsystem characteristics may be set with a call to function net_ioctl ( ). This call, for example, may specify the data rate of the sockets. 
   Once the network subsystem connection is established, a socket (or sockets) can be created and initialized through a call to function socket ( ). Before the socket functions can be used, however, the call to function socket ( ) may return a socket descriptor. Then, application  260  may call a function async_select ( ) to register specified events to receive asynchronous notification. This registration may be implemented by application  260 , as part of the function call, to specify the socket descriptor and a bit mask (i.e., multiple events OR&#39;ed together) of the specified events requiring notification. If a specified event occurs (i.e., it is enabled), and it is detected by communication protocol stack  280  or APi  270 , for example, the socket callback function is invoked to provide asynchronous notification. The callback function may notify application  260  of the specified event by the use of a signal, a message, including a message over remote procedure call (RPC), or a hardware or software interrupt. 
   Once application  260  is notified of the specified event, then it may call function getnextevent ( ) to determine the specified events to service. This function returns a mask of the specified events that occurred for the specified socket descriptor. Also, it clears the bits in the mask of the specified events that occurred. Thus, application  260  may no longer receive notification of the disabled specified events. Application  260  must re-register (i.e., re-enable) these specified events through a subsequent call to function async_select ( ). 
   In addition, application  260  may change the specified events registered for by clearing corresponding bits in the bit mask of specified events. If the bit is already cleared in the bit mask, then the request is simply ignored. In short, event notification may be disabled on a per-event basis, for example, through a call to function async_deselect ( ). 
     FIGS. 4 and 5  are flow charts for detecting the specified events. As shown in  FIG. 4 , for example, communication protocol stack  280  waits for application  260 , in block  400 , to register a specified event. After the specified event is registered, communication protocol stack  280 , in block  402 , polls a memory. In block  404 , the specified event may be detected based on the polled information of block  402 . In block  406 , the write event is detected, for example, when the memory of the communication protocol stack  280  (i.e., the send queue) is available to accept a sufficient amount of data. The data may be transmitted from application  260 . If the polled information of block  404  is not satisfactory (i.e., the specified event has not occurred), then communication protocol stack  280  continues to poll the memory, as in block  402 . 
   In  FIG. 5 , communication protocol stack  280  waits for application  260  to register a specified event, as indicated in block  500 . During this time, an interrupt notice may be disabled. As such, the interrupt notice cannot trigger or be triggered. After the specified event is registered, as in block  500 , the interrupt notice, in block  502 , may be triggered based on the occurrence of the specified event. The read event, for example, occurs when data is written into the memory of communication protocol stack  280  (i.e., the receive queue). Thus, in block  504 , the read event is detected by communication protocol stack  280  when it receives the interrupt notice, which was triggered due to the occurrence of the event. The data stored in the memory of the communication protocol stack  280  may be from the communication network. Further, for the read event, the stored data may be transmitted to application  260 . 
   Last, the close event is detected when a socket is available for re-use because, for example, a data link connection, such as the transport layer, is terminated. 
   The following examples of an asynchronous connection (see  FIG. 6 ) and an asynchronous input (see  FIG. 7 ) are provided to illustrate the use of asynchronous event notification. 
   Referring to  FIG. 6 , both communication protocol stack  280  is entered and the callback functions are specified through the call to function open_netlib ( ). The call to function pppopen ( ) (A) initiates the network subsystem connection (B). After the network subsystem connection has been established, the callback function is invoked (C) to report the availability of the network subsystem. 
   Assuming that a socket has been opened and allocated, a call to function connect ( ) (D) initiates a TCP connection (E). Further, application  260  calls function async_select ( ) (F) to register the specified events to receive notification. In this example, the specified event of interest is the write event, which occurs upon establishing a connection. 
   Upon establishing the connection, the callback function is invoked if the specified event is registered in the mask. If it is, then the callback function is invoked (G) to provide asynchronous notification. Once application  260  is notified, it calls function getnextevent ( ) (H) to determine which specified event occurred (I). Also, this call clears the bit of the event (i.e., the write event) in the mask (J). Application  260  must re-register subsequent notification of the specified event through the call to function async_select ( ). 
   In  FIG. 7 , an illustration of an asynchronous socket read is provided. To initiate the read, application  260  makes a call to function read ( ) (A). Assuming a lack of data to read, application  260  calls function async_select ( ) (B) to register an event (i.e., set the corresponding bit in the mask) to receive notification. In this example, the specified event of interest is the read event, which occurs when there is data to read by application  260 . 
   Upon the storage of data in the receive queue, the callback function is invoked if the read event is specified in the mask. If it is, then the callback function is invoked (C) to provide asynchronous notification. Once application  260  is notified, it calls function getnextevent ( ) (D) to determine which event occurred (E). Also, this call clears the bit of the event in the mask (F). Application  260  must re-enable subsequent notification of the event through the call to function async_select ( ). Last, to read the data stored in the receive queue, application  260  makes the call to function read ( ) (G). 
   In  FIGS. 8-10 , state machines of embodiments of the present invention are illustrated. In  FIGS. 8-9 , it is assumed that communication protocol stack  280  is opened and the network subsystem connection (i.e., traffic channel, and link layer if necessary—the raw sockets may bypass the network subsystem) is established. One skilled in the art would appreciate that various names for the states are possible without departing from the scope of the present invention. 
   The state machine, which may asynchronously transition between states, controls (i.e., enables and disables) the specified events, such as read, write, and close. The specified events may be disabled at the start of operation and may be enabled in predetermined states to assist application  260  to identify the state of MS  110 . 
   Also, API  270  reports specified status messages that are particular (i.e., not merely generic) to application  260  based on the state of API  270  and the type of function called by application  260 . The specified status messages may reflect the state of the underlying communication network. The status messages are reported to application  260  as arguments of the function calls, for example. 
   In  FIG. 8 , for example, a state diagram for a TCP socket of API  270  is illustrated. The uninitialized socket begins in the “null” state  800 . The socket does not “exist” because it has not been allocated, as of yet. The socket may be created and initialized through a call to function socket ( ), which returns the socket descriptor to use with socket-related functions. After the call to function socket ( ), the state machine transitions to an “initialize” state  805 . 
   In the initialize state  805 , the state machine transitions back to the null state  800  whenever the possibility of a TCP connection is terminated by a call to function close ( ). The call to function close ( ) releases all socket-related resources. On the other hand, a call to function connect ( ) initiates the TCP connection and transitions the state machine into an “opening” state  810 . 
   In the opening state  810 , the state machine transitions to a “closed” state  815  whenever: (1) a network subsystem failure occurs, (2) a failure to establish the TCP connection, or (3) a changed IP address. Also, after a call to function close ( ), which terminates the TCP connection, the state machine transitions the socket into a “closing” state  820  while the termination procedures are initiated. Last, the state machine transitions to an “open” state  825  upon the TCP connection being established. 
   In the open state  825 , the socket is open to read and write. In particular, the write event is immediately enabled, while the read event is enabled based on whether data is stored into the memory of the communication protocol stack  280 . The state machine transitions to the closed state  815  whenever: (1) the network subsystem failure occurs; (2) the failure to establish the TCP connection; (3) an attempt to terminate the TCP connection, such as a TCP reset, a TCP aborted, or a TCP closed initiated by a network server; and (4) the change of the IP address. An application initiated TCP connection termination, such as by a call to function close ( ), transitions the state machine to the closing state  820 . 
   In the closed state  815 , the read, write and close events are all asserted. After a call to function close ( ), which terminates the TCP connection, the state machine transitions the socket to the null state  800 , which frees up the socket and makes it available for re-use. 
   In the closing state  820 , the state machine transitions to a “wait for close” state  830  whenever: (1) the network subsystem failure occurs; (2) the attempt to terminate the TCP connection, such as the TCP reset, or the TCP closed initiated by the network server; (3) an expiration of a timer and (4) the change of the IP address. For protection against delay in terminating the TCP connection, the API  270  implements the timer, which is activated upon the initiating of the TCP connection termination. As seen, the expiration of the timer transitions the state machine to the wait for close state  830 . 
   In the wait for close state  830 , a call to function close ( ) terminates the TCP connection and transitions the state machine to the null state  800 . The close event is asserted in this state  830 . 
   Tables 1-3 illustrate specified status messages supported by API  270 . In the null state (not shown in Tables 1-3), a specified status message, which is descriptive, that “no additional resources are available” may be reported to application  260 . 
   
     
       
             
             
           
         
             
               TABLE 1 
             
             
                 
             
           
           
             
               State 
               Specified Status Messages for a Connect Function type 
             
             
               Initialize 
               If this were a blocking function call, the operation 
             
             
                 
               would block 
             
             
               Opening 
               Connection in progress 
             
             
               Open 
               Connection established 
             
             
               Closing 
               TCP connection does not exist due to lack of origination 
             
             
                 
               attempt, or the connection attempt failed 
             
             
               Wait for 
               TCP connection does not exist due to lack of origination 
             
             
               Close 
               attempt, or the connection attempt failed; or 
             
             
                 
               Generic network error; underlying network is not available 
             
             
               Closed 
               Generic network error; underlying network is not available; 
             
             
                 
               Connection attempt was refused due to a server reset; 
             
             
                 
               Connection in progress timed out; or 
             
             
                 
               Network level IP address changed, which caused the TCP 
             
             
                 
               connection to reset, due to a PPP resync 
             
             
                 
             
           
        
       
     
   
   
     
       
             
             
           
         
             
               TABLE 2 
             
             
                 
             
           
           
             
               State 
               Specified Status Messages for an I/O Function type 
             
             
               Initialize 
               TCP connection does not exist due to lack of origination 
             
             
                 
               attempt, or the connection attempt failed 
             
             
               Opening 
               If this were a blocking function call, the operation would 
             
             
                 
               block 
             
             
               Open 
               If this were a blocking function call, the operation would 
             
             
                 
               block (number of bytes read/written) 
             
             
               Closing 
               TCP connection does not exist due to lack of origination 
             
             
                 
               attempt, or the connection attempt failed 
             
             
               Wait for 
               TCP connection does not exist due to lack of origination 
             
             
               Close 
               attempt, or the connection attempt failed; or 
             
             
                 
               Generic network error; underlying network is not available 
             
             
               Closed 
               Generic network error; underlying network is not available; 
             
             
                 
               Server reset the connection; receipt of a server reset; 
             
             
                 
               TCP connection aborted due to a time-out or other reason; or 
             
             
                 
               TCP connection does not exist due to lack of origination 
             
             
                 
               attempt, or the connection attempt failed 
             
             
                 
             
           
        
       
     
   
   
     
       
             
             
           
         
             
               TABLE 3 
             
             
                 
             
           
           
             
               State 
               Specified Status Messages for a Close Function type 
             
             
               Initialize 
               Success-no error condition reported 
             
             
               Opening 
               If this were a blocking function call, the operation would 
             
             
                 
               block 
             
             
               Open 
               If this were a blocking function call, the operation would 
             
             
                 
               block 
             
             
               Closing 
               If this were a blocking function call, the operation would 
             
             
                 
               block 
             
             
               Wait for 
               Success-no error condition reported 
             
             
               Close 
             
             
               Closed 
               Success-no error condition reported 
             
             
                 
             
           
        
       
     
   
   By way of example,  FIG. 9  illustrates a state diagram for a UDP socket of API  270 . The uninitialized socket begins in a “null” state  900 . As noted above with respect to the null state  800 , the socket does not “exist” because it has not been allocated. The socket may be created and initialized through a call to function socket ( ), which returns the socket descriptor to use with socket-related functions. After the call to function socket ( ), the state machine transitions to an “open” state  905 . 
   In the open state  905 , the socket is open to read and write. In particular, the write event is immediately enabled, while the read event is enabled based on whether data is stored into the memory of the communication protocol stack  280 . The state machine transitions to a “closed” state  910  whenever the network subsystem failure occurs. An application initiated UDP connection termination, such as by a call to function close ( ), transitions the state machine to the null state  900 . 
   In the closed state  910 , the read, write, and close events are all enabled. After a call to function close ( ), which terminates the UDP connection, the state machine transitions the socket to the null state  900 , which frees up the socket and makes it available for re-use. 
   Tables 4-6 illustrate specified status messages supported by API  270 . In the null state (not shown in Tables 4-6), the specified status message that “no additional resources are available,” as stated above, may be reported to application  260 . 
   
     
       
             
             
           
         
             
               TABLE 4 
             
             
                 
             
           
           
             
               State 
               Specified Status Messages for a Connect Function type 
             
             
               Open 
               Success-no error condition reported 
             
             
               Closed 
               Generic network error; underlying network is not available 
             
             
                 
             
           
        
       
     
   
   
     
       
             
             
           
         
             
               TABLE 5 
             
             
                 
             
           
           
             
               State 
               Specified Status Messages for an I/O Function Type 
             
             
               Open 
               If this were a blocking function call, the operation would 
             
             
                 
               block (number of bytes read/written) 
             
             
               Closed 
               Generic network error; underlying network is not available 
             
             
                 
             
           
        
       
     
   
   
     
       
             
             
             
           
         
             
                 
               TABLE 6 
             
             
                 
                 
             
           
           
             
                 
               State 
               Specified Status Messages for a Close Function Type 
             
             
                 
               Open 
               Success-no error condition reported 
             
             
                 
               Closed 
               Success-no error condition reported 
             
             
                 
                 
             
           
        
       
     
   
     FIG. 10  illustrates a state diagram to control the network subsystem, such as the traffic channel (i.e., Um) and the link-layer (i.e., PPP  206 ). A call to function open_netlib ( ) opens the network subsystem, and initializes a socket into a “closed” state  1000 . A call to function pppopen ( ) initiates the network subsystem connection, which transitions the socket to an “opening” state  1005 . Also, a page to the MS  110  by an incoming PPP call transitions the socket to the opening state  1005 . In both cases, upon successful negotiation, the MS  110  attempts to synchronize and establish both RLP and PPP across the traffic channel. 
   In the opening state  1005 , the socket transitions to an “open” state  1010  upon the network subsystem connection being established. On the other hand, the socket transitions back to the closed state  1000  if the network subsystem connection is not established. 
   In the open state  1010 , the callback function is invoked to identify to application  1060  specified events, such as read, write, and close, that are enabled. At this time, the MS  110  can communicate through the traffic channel. The socket, however, transitions to the closed state  1000  whenever network subsystem failure occurs, which invokes the callback function. An application initiated network subsystem connection termination, such as by a call to function close ( ), transitions the socket to a “closing” state  1015 . 
   In the closing state  1015 , the socket transitions to the closed state  1000  whenever the network subsystem connection is terminated. In the closed state  1000 , the callback function is invoked to identify to application  260  specified events that are enabled. 
   Table 7 illustrates specified status messages that correspond to particular function calls, and that are supported by API  270 . 
   
     
       
             
             
           
         
             
               TABLE 7 
             
             
                 
             
             
               Function 
                 
             
             
               Call (and 
             
             
               description) 
               Specified Status Messages 
             
             
                 
             
           
           
             
               socket () 
               Address not supported; 
             
             
               creates a socket 
               Invalid Application Identifier; 
             
             
               and returns a 
               Protocol is wrong type for socket; 
             
             
               socket 
               Invalid or unsupported socket parameter; 
             
             
               descriptor 
               Protocol not supported; or 
             
             
                 
               No more socket resources available 
             
             
               connect () 
               If this were a blocking function call, the operation would 
             
             
               initiates TCP 
               block; 
             
             
               connection 
               Invalid socket descriptor; 
             
             
                 
               Connection attempt was refused due to receipt of a server 
             
             
                 
               reset; 
             
             
                 
               Connection timed out; 
             
             
                 
               Application buffer not part of valid address space; invalid 
             
             
                 
               size specified for address length or message length; 
             
             
                 
               Network level IP address changed, which caused the TCP 
             
             
                 
               connection to reset, due to a PPP resync; 
             
             
                 
               Connection in progress; 
             
             
                 
               Socket descriptor already connected; 
             
             
                 
               Generic network error; underlying network is 
             
             
                 
               unavailable; 
             
             
                 
               Invalid server address specified; 
             
             
                 
               Address already in use; or 
             
             
                 
               Destination Address Required 
             
             
               pppopen () 
               If this were a blocking function call, the operation would 
             
             
               establishes 
               block; 
             
             
               network 
               Invalid application identifier specified; or 
             
             
               connection 
               Termination of network connection in progress 
             
             
               net_ioctl () 
               Invalid application identifier specified; 
             
             
               sets network 
               Invalid request or parameter; 
             
             
               characteristics 
               Network connection established; 
             
             
                 
               Network connection in progress 
             
             
               open_netlib () 
               No more applications available-maximum number of 
             
             
               opens 
               open applications exceeded 
             
             
               communication 
             
             
               protocol stack 
             
             
               close_netlib () 
               Invalid application identifier specified; 
             
             
               closes 
               There are existing, allocated sockets; or 
             
             
               communication 
               Network connection is still established 
             
             
               protocol stack 
             
             
               bind () 
               Invalid socket descriptor specified; 
             
             
               for client 
               Invalid or unsupported operation specified; 
             
             
               sockets, 
               Address already in use; 
             
             
               attaches a local 
               Invalid operation; or 
             
             
               address and 
               Invalid address parameter specified 
             
             
               port value 
             
             
               to the socket 
             
             
               close () 
               Invalid socket descriptor specified; or 
             
             
               closes a socket 
               If this were a blocking function call, the operation would 
             
             
               to free it 
               block 
             
             
               for re-use 
             
             
               pppclose () 
               If this were a blocking function call, the operation would 
             
             
               closes network 
               block; 
             
             
               connection 
               Invalid application identifier specified; or 
             
             
                 
               Termination of network connection in progress 
             
             
               netstatus () 
               Invalid application identifier specified; 
             
             
               reports status 
               Underlying network is unavailable; 
             
             
               of network 
               Network connection established and available; 
             
             
               connection 
               Network connection in progress; 
             
             
                 
               Termination of network connection in progress; 
             
             
                 
               No CDMA (i.e., traffic channel) service available; 
             
             
                 
               CDMA service available, but origination failed because 
             
             
                 
               base station does not support service option; or 
             
             
                 
               CDMA service available, but origination failed; however, 
             
             
                 
               not because base station does not support the service 
             
             
                 
               option 
             
             
               async_select () 
               Invalid socket descriptor specified 
             
             
               registers spec- 
             
             
               ified events 
             
             
               for a particular 
             
             
               socket 
             
             
               getnextevent () 
               Invalid socket descriptor specified; or 
             
             
               get the next 
               Invalid application identifier specified 
             
             
               socket des- 
             
             
               criptor and 
             
             
               events that 
             
             
               have occurred 
             
             
               write () 
               Invalid socket descriptor specified; 
             
             
               write a spec- 
               No existing TCP connection; 
             
             
               ified number of 
               Server reset the TCP connection; 
             
             
               byte-contig- 
               TCP connection aborted due to timeout or other failure; 
             
             
               uous or non- 
               Network level IP address changed, which caused the TCP 
             
             
               contiguous 
               connection to reset, due to a PPP resync; 
             
             
               buffers 
               TCP connection closed; 
             
             
                 
               Network unavailable; 
             
             
                 
               Application buffer not valid part of address space; or 
             
             
                 
               No free buffers available for writing 
             
             
               read () 
               Invalid socket descriptor specified; 
             
             
               read a specified 
               No existing TCP connection; 
             
             
               number of 
               Server reset the TCP connection; 
             
             
               bytes-contig- 
               TCP connection aborted due to timeout or other failure; 
             
             
               uous or non- 
               Network level IP address changed, which caused the TCP 
             
             
               contiguous 
               connection to reset, due to a PPP resync; 
             
             
               buffers 
               TCP connection closed; 
             
             
                 
               Network unavailable; 
             
             
                 
               Application buffer not valid part of address space; 
             
             
                 
               No free buffers available for reading; or 
             
             
                 
               End of file marker received 
             
             
               sendto () 
               Invalid socket descriptor specified; 
             
             
               send a spec- 
               Address family not supported; 
             
             
               ified number 
               No free buffers available for writing; 
             
             
               of bytes 
               Network unavailable; 
             
             
                 
               Application buffer not valid part of address space; 
             
             
                 
               Specified option not supported; or 
             
             
                 
               Destination address requested 
             
             
               recvfrom () 
               Invalid socket descriptor specified; 
             
             
               reads a spec- 
               Address family not supported; 
             
             
               ified number 
               No free buffers available for writing; 
             
             
               of bytes 
               Network unavailable; 
             
             
                 
               Application buffer not valid part of address space; or 
             
             
                 
               Specified option not supported 
             
             
                 
             
           
        
       
     
   
   In another embodiment, a machine may read a machine-readable medium comprising encoded information, such as encoded software code, to cause the processes described above that enables a mobile station application to receive and transmit raw packetized data. The machine-readable medium may accept the encoded information from a storage device, such as a memory or a storage disk, or from the communication network. Also, the machine-readable medium may be programmed with the encoded information when the medium is manufactured. The machine may comprise at least one of application  260 , communication protocol stack  280 , and API  270 , while the machine-readable medium may comprise a memory or a storage disk. 
   Although this invention has been shown in relation to particular embodiments, it should not be considered so limited. Rather, the invention is limited only by the scope of the appended claims and their equivalents.