IL119428A

IL119428A - Method and system for communication over a wireless modem

Info

Publication number: IL119428A
Application number: IL11942896A
Authority: IL
Original assignee: Motorola Israel Ltd
Priority date: 1995-11-23
Filing date: 1996-10-15
Publication date: 2001-08-08
Also published as: GB2307625A; GB9523971D0; IL119428A0; FR2741765B1; DE19648289A1; FR2741765A1; GB2307625B

Abstract

At a computing system (100), communication over a wireless modem is effected by invoking socket calls corresponding to a Sockets protocol standard. Sockets emulation for the Sockets protocol standard is provided by translating the first set of socket calls into service calls that control the wireless modem, and that perform communication through the wireless modem. A destination address is determined using a parameter referenced by one of the socket calls A particular data format is selected based at least in part on a configuration source. A data packet is formed according to the particular data format that contains particular data referenced one of the socket calls, and any information necessary to route the data packet to the destination address. The data packet is transmitted over the communication link using the wireless modem. Remote units (102-104) are PC's with wireless modems and Winsock sockets.

Description

Method and system for communication over a wireless modem MOTOROLA ISRAEL LIMITED C. 103946 METHOD AND SYSTEM FOR COMMUNICATION OVER A WTRELESS MODEM Technical Field This invention relates in general to networked computer systems, and particularly, to systems employing wireless communication links between computing devices.

Background of the Invention There are many situations in which a data terminal or other computing device requires untethered access to a host computer, or a network of computers. A common solution is to associate a wireless modem with the computing device and to establish a communication link with a host computer over a wireless communication network, such as a radio frequency (RF) network. In a typical environment, a communication application executes on the computing device and directly manipulates the wireless modem according to a protocol for communicating over the wireless network. Usually, there is a companion program executing on the host computer that facilitates information exchange between the computing device and the host computer.

Oftentimes, an application executing on one computing device needs to communicate with another application on the same or other computing device. The prior art teaches a variety of messaging systems that facilitate such communication over a wired network. For example, messaging systems based on the Berkeley Sockets programming model from the University of California at Berkeley, have been implemented on a variety of platforms. Sockets has become a de facto standard for networks using transmission control protocol / internet protocol (TCP/IP). TCP/IP corresponds to the transport and network layers of the open systems interaction (OSI) model that has been adopted to promote compatibility for network communications. The Sockets protocol is generally built on top of the transport layer protocol according to the OSI model.

Problems arise when adapting communication protocols developed for wired networks, such as TCP/IP, for communication over a wireless data network. Communication over a wireless data network may involve significant propagation delays due to access and bandwidth limitation issues.

Accordingly, applications requiring information exchange over a wireless network have tended to use communication protocols that are more suitable for a typical wireless network.

The nature of many such protocols for operating on a network over a wireless modem is such that an appli cation is aware of its environment. This awareness includes knowledge that information is being communicated over the wireless network, and some knowledge of the operation of the wireless data network. This affects the flexibility and portability of the application, and the application development time. Accordingly, a need exists to provide for communication between applications over a wireless modem with improved flexibility and transparency.

Summary of the Invention The present invention provides for communication over a wireless modem between computing devices using Sockets protocol emulation. At a first computing device that includes a wireless modem, an application invokes a set of socket calls that correspond to a standard Sockets protocol implementation. A Sockets emulator translates the socket calls into service calls that control the wireless modem. The Sockets emulator forms data packets, according to a particular format, that contains information necessary to route the data packet to a referenced destination. The data packet format is based in part on a configuration source, and includes at least the destination address when the target recipient is compatible with Sockets emulation.

Brief Description of the Drawings * FIG. 1 is a block diagram of a networked computer system that includes wireless communication links, in accordance with the present invention.

FIG. 2 is a block diagram of a communication link between applications on different computing devices highlighting various communication protocol layers, in accordance with the present invention.

FIG. 3 is a block diagram of a computing system highlighting functional aspects of an application environment, in accordance with the present invention.

FIG. 4 is a block diagram highUghting selected aspects of Sockets emulation, in accordance with the present invention.

FIG. 5 is a flow chart of procedures used at the computing system of FIG. 3, to communicate over a wireless modem, in accordance with the present invention.

FIG. 6 is a block diagram showing components of a radio network gateway.

FIG. 7 is a flow chart of procedures used at the radio network gateway of FIG. 6, in accordance with the present invention.

FIG. 8 is a block diagram showing functional components of a host computer, in accordance with the present invention.

FIG. 9 is a flow chart of procedures used at the host computer of FIG. 8 for processing data packets based on Sockets emulation, in accordance with the present invention.

Detailed Description of the Preferred Embodiment While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the drawing figures, in which like reference numerals are carried forward.

FIG. 1 is a block diagram of a networked computer system 100, that includes wireless communication links among computing devices, in accordance with the present invention. The system 100 includes host computers or host computing systems 121, 122, and a radio network gateway 123 linked by a wired network 120. Remotely situated computing devices or computing systems 101, 102, 103, 104, such as portable computers or data tenmnals, are linked to the host computers through wireless radio frequency (RF) links 111, 112, 113, 114, either directly or through the radio network gateway 123. In a preferred embodiment, the system 100 provides data collection and data presentation support via the remote computing devices. Thus, the remote computing devices function as data terminal equipment (DTE) that interface with host computing devices.

Preferably, the remote computing devices 101, 102, 103, 104 are personal computer (PC) class computing devices capable of supporting one or more application programs. In the preferred embodiment, the remote computing device support the Microsoft® Windows™ operating system that includes the Winsock implementation of Sockets, as a Sockets protocol standard. Winsock includes application programming interface (API) libraries, network services and protocol support files. The remote computing devices also include a wireless radio frequency modem and driver for interfacing with a particular RF network. The RF network may be self-maintained or may be available through a service provider. Preferably, the remote computing devices include an application program for data collection and/or data presentation, such that the computing devices function as data terminals.

The host computers 121, 122 interface over the wireless communication link with the remote computing devices 101, 102, 103, 104. For illustration purposes, at least one host computer 121 does not support the Sockets emulation of the present invention, and at least one host computer 122 is compatible with the Sockets emulation of the present invention.

The radio network gateway 123, provides routing services for communication from a remote computing device to one or more host computing devices. A networked computer system may or may not contain a radio network gateway 123. According to the network configuration of the preferred embodiment, communication links may exist between a DTE and a host computer, such as between remote device 101 and host 121 via link 111, or between two DTE devices 103, 104, such as by interfacing through the radio network gateway 123 via links 113 and 114.

According to the present invention, an application executing on a remote computing device communicates with an application executing on a host computing device over a wireless communication link using Sockets emulation, when such application on the host computing device is compatible with the Socket emulation of the application on the remote computing device.

FIG. 2 is a block diagram highlighting various communication protocol layers of a Sockets based communication link over a wireless modem between a host computer and a remote computing device, in accordance with the present invention. At the remote computing device or DTE, a remote application 210 interfaces with a wireless modem 220. The remote application 210 comprises a remote application layer 211, a Sockets emulation layer 212, and a layer for handling modem service calls 215. The remote application 210 interfaces with a driver for a wireless modem 220, using a RF-modem device protocol. The wireless modem 220 and its associated software, translates modem service calls 225 to radio network protocol 224 for communicating across a wireless radio frequency communication link 205.

Preferably, the radio network uses a radio network controller 230 that includes a radio network layer 234 for managing communications across the wireless link 205, and a network controller protocol layer 233 for handling higher level communications. Optionally, the communication link may include a radio network gateway 240. The radio network gateway 240 includes a network controller protocol layer 243 for communicating with the radio network controller 230, and a radio network gateway protocol layer 242 for interpreting and routing communications. In the preferred embodiment, the radio network gateway layer 242 provides context based routing, in which the destination of a routed data packet depends on the content of at least a portion of the data packet.

At the host computer, a host application 250 includes a network controller protocol layer 253 for interfacing with the radio network controller 230, a Sockets emulation translation layer 252 that handles Sockets type communication, and a host application layer 251. With the Sockets emulation translation layer 252, the host application 250 is compatible with the Sockets emulation 212 of the remote application 210. Preferably, both the host application layer 251, and the remote application layer 211 support Sockets through a set of standard Sockets protocol calls.

FIG. 3 is a block diagram of a remote computing system or DTE 300 highlighting functional aspects of an application environment, in accordance with the present invention. The computing system 300 includes a configuration source 335, an application 310, a Sockets emulator 312, and a RF modem 305. These functional aspects 335, 310, 312, 305 are shown separately for illustrative purposes and do not necessarily dictate structural organization on a computing device. The application 310 is a data collection and/or data presentation application that is typically found in data terminal equipment (DTE) applications. The Sockets emulator 312 provides the means through which the application 310 communicates via the RF modem 305. Further aspects of the Sockets emulator will be described in more detail below. The configuration source 335 provides information corresponding to the communication environment of the computing system 300. Preferably, the configuration source provides information on network services, protocol, hosts configurations, and the like. In the preferred embodiment, the configuration source comprises standard network resources files, such as a host configuration file, a network services file, and the like. However, the configuration source 335 may constitute memory accessible by the Sockets emulator.

FIG. 4 is a block diagram 400 highlighting selected aspects of Sockets emulation, in accordance with the present invention. At a layer corresponding to the application 310, a set of socket calls is supported. The socket calls supported correspond to the Sockets protocol standard, such as the Winsock implementation of Sockets of the preferred embodiment. In the preferred embodiment, the socket calls support registration 415, sending and receiving information via Sockets 416, 417, and notification messages 418 relating to information packets sent via a socket call to a Sockets emulation compatible recipient. Note that the notification messages 418 are not normally associated with standard Sockets function calls. At a Sockets application programming interface (API) 420, standard set of socket calls are supported. For example, socketO, bindO, connectO, and select() are functions typically provided for registration 415. SendtoO and send() are function calls provided for Sockets send operations 416. For receive operations, recvfromO, and recvO function calls are provided.

According to the present invention, the Sockets API 420 is supported by Sockets emulation. At a layer corresponding to the Sockets emulator 312, Sockets emulation for the Sockets protocol standard is provided by translating the set of socket calls at the application layer 310 into service calls that control the wireless modem 305. For example, during Sockets emulation, data 442 to be sent across the modem 305 is packaged by one or more modules 440. The data 442 is combined with a destination information or address 441, and preferably local address information 443 according to a data format 445 based on the configuration source 335 to form a data packet 449. In the preferred embodiment, the destination information is placed in a header portion of the data packet.

Preferably, the Sockets emulator 312 supports at least three data packet formats based at least in part on information from the configuration source 335. A first data packet format includes particular data 442, and the destination address 441, when the data packet is destined to a recipient that is compatible with the Sockets emulation. A second data packet format includes particular data 442, the destination address 441, and radio network gateway routing control information 446, when the data packet is destined to a recipient across a communication link that includes a radio network gateway. A third data packet format does not include the destination address 441, when the data packet is destined to a recipient that is not compatible with the Sockets emulation.

For receive operations, a data packet 451 received via the wireless modem 305 is unpackaged to separate source address 453, if any, and data 454. The data packet is unpackaged by one or more modules 450, according to one of the supported data formats 445. The Sockets emulator 312 also includes one or more modules 460 that supports acknowledgment of messages sent via socket calls, as an extension to the standard Sockets protocol support.

FIG. 5 is a flow chart of procedures 500 at a computing system for communicating over a wireless modem, in accordance with the present invention. In an application on the computing system, a set of socket calls is invoked that correspond to a Sockets protocol standard. In preparation for communications using socket calls, one or more socket registration calls are invoked, step 510. For sending a message via Sockets, a socket send call is invoked, step 520.

According to the present invention, Sockets emulation is provided by translating the socket calls into service calls that control the wireless modem, and that perform communication through the wireless modem. For emulation of a socket send call, a destination address is determined using a parameter reference by at least one socket call, step 530. Generally, the destination address will be available from a send socket function call parameter, or will have been established by Sockets registration calls. A particular data format is selected based at least in part on the configuration source, step 540. The configuration source may comprise a file or a database having information on network services and host configurations. The particular data packet format is used in formatting the data to be sent, step 550. The data packet formed contains particular data referenced by at least one socket call, and any information necessary to route the data packet to the destination address. In the preferred embodiment, the data format is selected to include radio gateway control information, when the communication link includes a radio network gateway; and a destination address as part of the data, when the destination address corresponds to a recipient that is compatible with socket simulation. The data format excludes the destination address when the recipient is not compatible with Sockets emulation. The data packet is then transmitted over the communication link using the wireless modem, step 560. FIG. 6 is a block diagram showing components of a radio network gateway 600, in accordance with the present invention. In the preferred embodiment, the radio network gateway is a special purpose computing device configured to perform context based routing on data packets received.

Accordingly, the radio network gateway 600 includes a router 611, and a communication link interface 613. FIG. 7 is a flow chart of procedures 700 used by the radio network gateway of FIG. 6. The radio network gateway 600 operates to receive data packets over the communication link, step 710, to extract control information from the data packet, step 720, and to perform context based routing on the data packet according to the extracted control information, step 730.

FIG. 8 is a block diagram showing functional components of a host computer system 800, in accordance with the present invention. The host computing system includes a host application 811, a Sockets emulation translator 812, and a communication link interface 813. FIG. 9 is a flow chart of procedures used at the host computing system of FIG. 8. A set of socket calls corresponding to a Sockets protocol standard is invoked for communication, steps 910, 920. For example, to receive a message via a Sockets, socket registration calls are invoked, step 910, and one or more socket calls for receiving data is invoked, step 920. These socket calls are translated into service calls that receive a data packet over the communication link, step 930. The data packet is interpreted according to a Sockets emulation data packet format, step 940.

The present invention provides significant benefits over the prior art. Application development for devices employing communication links across a wireless modem can be developed to be wireless protocol and wireless network transparent by using standard Sockets calls. This provides a significant advantage over prior art implementations which typically support a protocol interface between the modem and a DTE application, but require that application developers design around the wireless network.

While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not so hmited. Numerous modifications, changes, variations, substitutions and equivalents will occur to those skilled in the art without departing from the spirit and scope of the present invention as defined by the appended claims.

What is claimed is:

Claims

CM00460S 10 Claims

1. A method for con-u inicating between computing systems over a communication link, mcluding a wireless modem, the method comprising the steps of: at a first computing system: invoking a first set of socket calls corresponding to a Sockets protocol standard; providing Sockets emulation for the Sockets protocol standard by translating the first set of socket calls into service calls that control the wireless modem, and that perform communication through the wireless modem, mcluding the steps of: detennining a destination address using a parameter referenced by at least one of the first set of socket calls; selecting a particular data format based at least in part on a configuration source; forming a data packet according to the particular data format, the data packet containing particular data referenced by at least one of the first set of socket calls, and any information necessary to route the data packet to the destination address; and transmitting the data packet over the communication link using the wireless modem.

2. The method of claim 1, wherein the step of selecting a particular data format comprises the step of selecting, as the particular data format, a data format that includes radio gateway control information, when the communication link includes a radio network gateway.

3. The method of claim 1 or 2, wherein the step of selecting a particular data format comprises the step of selecting, as the particular data format, a data format that includes the destination address as part of the data, when the destination address corresponds to a recipient that is compatible with the Sockets emulation. CM00460S 11

4. The method of claim 3, wherein the step of selecting a particialar data format comprises the step of selecting, as the particular data format, a data format that does not include destination address as part of the data, when the destination address corresponds to a recipient that is not compatible with the Sockets emulation.

5. The method of claim 1, 2, 3, or 4, wherein the step of selecting a particular data format comprises the step of retrieving information from a database that describes host configurations and network services.

6. The method of claim 1, 2, 3, 4, or 5, wherein the step of forming a data packet comprises the step of inserting the destination address into the data packet.

7. The method of claim 6, further comprising the steps of: at a second computing system: interpreting the data packet according to the Sockets emulation, mcluding the steps of: receiving the data packet over the communication link; extracting routing control information from the data packet; and routing the data packet according to the routing control information.

8. The method of claim 6, further comprising the steps of: at a second computing system: invoking a second set of socket calls corresponding to the Sockets protocol standard; translating the second set of socket calls into service calls that: receive the data packet over the communication link; and interpret the data packet according to the Sockets emulation.

9. A system that provides wireless data communication, including a first computing system, comprising: a wireless modem; CM00460S 12 a first application having socket calls corresponding to a Sockets protocol standard; a Sockets emulator for providing Sockets emulation that translates the socket calls into service calls to control the wireless modem, and to perform communication through the wireless modem; and a configuration source having information on network services and host configurations; wherein the Sockets emulator is responsive to at least one of the socket calls to invoke the service calls to transmit a data packet using the wireless modem, the data packet including particular data formatted according to at least one data packet format, wherein at least one of the at least one data packet format includes a destination address corresponding to a socket address.

10. The system of claim 9, further comprising: a second computing system linked to the first computing system by a communication link, the second computing system comprising: a second application having socket calls corresponding to a Sockets protocol standard; and a translator for interpreting the data packet according to the Sockets emulation.

11. The system of claim 10, wherein the second computing system is linked through a radio network gateway.

12. The system of claim 9, 10, or 11 wherein the data packet comprises a header portion containing the destination address.

13. The system of claim 9, 10, or 11 wherein the Sockets protocol standard comprises a Winsock protocol of a Windows operating system.

14. The system of claim 9, 10, or 11 wherein the Sockets emulator supports an acknowledgment provision for a data packet sent to a Sockets emulation compatible recipient. CM00460S 13

15. The system of claim 9, 10, or 11 wherein the Sockets emulator supports at least three data packet formats based at least in part on information from the configuration source, the at least three data packet formats mcluding: a first data packet format including the destination address and the particular data when the data packet is destined to a recipient that is compatible with the Sockets emulation; a second data packet format mcluding radio gateway control information, the destination address and the particular data, when the data packet is destined to a recipient across a communication link that includes a radio network gateway; and a third data packet format that does not include the destination address, when the data packet is destined to a recipient that is not compatible with the Sockets emulation. For the Applicants REINHOLD COHN AND PARTNERS