Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
CA 02386585 2002-06-12
DEVICE FOR DATA COMMUNICATIONS BETWEEN
WIRELESS APPLICATION PROTOCOL TERMINAL AND
WIRELESS APPLICATION SERVER, AND METHOD THEREOF
BACKGROUND OF THE INVENTION
s 1. Field of the Invention
The present invention relates to data communications, and more particularly,
to a device for data communications between a Wireless Application Protocol
(WAP) terminal and a WAP server, and a method thereof.
2. Description of the Related Art
~o In general, a WAP server is connected between an Internet server which
provides various information and a WAP terminal capable of receiving the
information provided from the Internet server, to convert different data
formats and
different protocols between the Internet server and the WAP terminal. Also,
the
WAP server can provide the WAP terminal with its own information.
~s FIG. 1 is a block diagram of a conventional data communications device
between a WAP terminal and a WAP server.
The data communications device of FIG. 1 comprises a WAP terminal 10, an
interworking function (IWF) unit 12, a public switched telephone network
(PSTN) 13,
an Internet service provider (ISP) 14 and a WAP server 16.
2o The IWF unit 12 performs routing functions between the WAP terminal 10
and the ISP 14. The ISP 14 is one of companies providing general communication
service such as HITEL or UNITEL. The WAP server 16 provides the WAP terminal
with its own information and much information from an Internet server (not
shown).
zs FIG. 2 shows a protocol stack of each block of the data communications
device shown in FIG. 1.
A protocol stack of the WAP terminal 10 consists of a plurality of protocol
layers including a Circuit Switch Data services protocol (CSD(IS-707)), a Peer-
to-
Peer Protocol (PPP), an Internet Protocol (1P), a Wireless Transaction
Protocol
30 (WTP) and User Data Program Protocol (UDP), a Wireless Session Protocol
(WSP)
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CA 02386585 2002-06-12
and a Wireless Application Environment protocol (WAE). Also, the CSD(IS-707)
includes an IS-95 protocol, a Radio Link Protocol (RLP), a PPP, an IP and a
TCP.
The protocol layers are well known to those skilled in the art, so explanation
thereof
will be omitted.
s FIG. 4 is a diagram illustrating data flow in the data communications device
shown in FIG. 1.
The operation of the data communications device of FIG. 1 will be described
with reference to FIG. 4.
It is assumed that the WAP terminal 10 intends to receive Internet or
electronic mail (E-mail) services. Here, the WAP terminal 10 is ready to
receive a
common call or data (Internet or E-mail) in a normal state. When a user of the
WAP
terminal 10 connects the WAP terminal 10 through the IWF unit 12 and the PSTN
13 to the ISP 14 using a telephone number for connection with the Internet,
the ISP
14 connected to the WAP terminal 10 allows the user to receive the Internet or
E-
~s mail services. Also, when the user wants to stop receiving the Internet
services, the
ISP 14 disconnects the call from the WAP terminal 10, returning to the ready
state.
In detail, the WAP terminal 10 sends an Origination Message requesting
connection of its call to the IWF unit 12. The IWF unit 12 receives the
Origination
Message from the WAP terminal 10, and then sends an Origination Ack message
2o acknowledging reception to the WAP terminal 10. The IWF unit 12 sends a
Connect Request message for connection of a modem to the ISP 14. The ISP 14
receives the Connect Request message and sends a Connect <rate> message
indicating the connection of the modem through the PSTN 13 and the IWF unit 12
to
the WAP terminal 10. Under conditions that the WAP terminal 10 and the IWP
unit
Zs 12 are connected to each other, the WAP terminal 10 sends WAP data
(Internet or
E-mail services request data) which the user wants to receive through the IWF
12
and the ISP 14, to the WAP server 16. After the WAP server 16 receives the WAP
data, the WAP server 16 sends WAP server data which is retained in the WAP
server itself, or data taken from an Internet server (not shown) through the
ISP 14,
so the PSTN 13 and the IWP 12 to the WAP terminal 10.
The data communications device of FIG. 1, having the protocol stack as
shown in FIG. 2, has the following problems.
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First, because the CSD(IS~-707) in the protocol stack of the WAP terminal 10
includes the IP/PPP as shown in FIG. 3, the protocol stack of the WAP terminal
10
has IP/PPP protocol layers in duplicate. As a result, there is much overhead
during
transmission of data, so that transmission efficiency becomes low. That is,
the
s resources of the terminal are not efficiently used. Also, when a user
intends to
connect to the WAP server 16 or the Internet, connection with the ISP 14 is
achieved through the PSTN 14. Thus, the connection rate becomes slow down, and
using the PSTN and the ISP 14 may be subject to charges by the telephone
company or the ISP. Also, the transmission of data is inefficient because it
requires
multiple steps as shown in FIG. 4
SUMMARY OF THE fNVENTION
To solve the above problems, it is a first object of the present invention to
provide a device for data communications between a Wireless Application
Protocol
(WAP) protocol and a WAP server, adopting a protocol stack in which a single
,5 Internet Protocol/Peer-to-Peer Protocol (IPIPPP) layer included in a
Circuit Switch
Data services (ISD) protocol of the WAP terminal is used and an interworking
function (IWF) unit also acts as an Internet service provider (ISP).
It is a second object of the present invention to provide a communication
method of the data communications device for the first object.
zo It is a third object of the present invention to provide a device for data
communications between a WAP terminal and WAP server, which performs data
communications while performing switching between the WAP terminal and a non-
WAP terminal.
It is a fourth object of the present invention to provide a communication
2s method of the data communications device for the third object.
Accordingly, to achieve the above first object, there is provided a device for
data communications between a Wireless Application Protocol (WAP) terminal and
a WAP server, comprising: a plurality of WAP terminals each having a protocol
stack in which a Circuit Switch Data service (CSD) protocol layer is laid
under a
so Wireless Transaction Protocol (WTP) layer and a Wireless Datagram Protocol
(WDP) layer, for generating WAP data which is service request data; a
plurality of
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WAP servers each having a protocol stack in which a Transmission Control
Protocol
(TCP) layer and an Internet Protocol (1P) layer are laid under a WTP layer and
a
WDP layer, for providing the WAP terminals with WAP server data according to
the
WAP data; and an interworking function (IWF) unit having a CSD protocol layer
s connected to the CSD protocol layers of each WAP terminal, and a TCP layer
and
an IP layer which are connected to the TCP and IP layers of each WAP server,
for
mapping the WAP terminals to the corresponding WAP servers, wherein each WAP
terminal communicates with the IWF unit though a single Internet ProtocoIIPeer-
to-
Peer Protocol (IPIPPP) layer included in its own CSD protocol layer, and the
IWF
,o unit communicates through the Internet with each WAP server.
To achieve the second object, there is provided a communication method of a
data communications device including a plurality of WAP terminals having a
protocol stack in which a Circuit Switch Data service (CSD) protocol layer is
laid
under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram
~s Protocol (WDP) layer, a plurality of WAP servers having a protocol stack in
which a
Transmission Control Protocol (TCP) layer and an Internet Protocol (1P) layer
are
laid under a WTP layer and a WDP layer, and an interworking function (IWF)
unit
having a CSD protocol layer connected to the CSD protocol layers of each WAP
terminal, and a TCP layer and an IP layer which are connected to the TCP and
IP
20 layers of each WAP server, for communications between each WAP.terminal and
each WAP server, the method comprising the steps of: (a) transferring an
Origination Message for a call connection from each WAP terminal to the 1WF
unit,
and transferring an Origination ACK from the IWF unit to the corresponding WAP
terminal in response to the Origination Message; (b) receiving WAP data which
is
2s service request data for the WAP servers from the WAP terminals, to map
each
WAP terminal to the corresponding WAP server in the IWF unit, and transferring
the
received WAP data through the Internet to the corresponding WAP server; (c)
receiving the WAP data to generate WAP server data according to the received
WAP data in each WAP server, and transferring the WAP server data through the
3o Internet to the IWF unit; (d) receiving the WAP server data transferred in
the step (c)
to map the WAP servers to the corresponding WAP terminals in the IWF unit, and
transferring the received WAP server data to the corresponding WAP terminals;
and
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(e) communicating in the WAP terminals with the IWF unit through a single
Internet
ProtocoI/Peer-to-Peer Protocol (IP/PPP) layer contained in each Circuit Switch
Data
service (CSD) protocol layer of the WAP terminals.
To achieve the third object, there is. provided a device for data
s communications between a Wireless Application Protocol (WAP) terminal and a
WAP server, comprising: a plurality of WAP terminals each having a protocol
stack
in which a Circuit Switch Data service (CSD) protocol layer is laid under a
Wireless
Transaction Protocol (WTP) layer and a Wireless Datagram Protocol (WDP) layer,
for generating WAP data which is service request data; a non-WAP terminal for
~o generating a common circuit data; a plurality of WAP servers each having a
protocol
stack in which at least a Transmission Control Protocol (TCP) layer and an
Internet
Protocol (1P) layer are laid under a WTP layer and a WDP layer, for providing
the
WAP terminals with WAP server data according to the WAP data; an Internet
server
for providing the non-WAP terminal with Internet server data according to the
~s common circuit data; an Internet service provider (ISP) having a public
switched
telephone network (PSTN) circuit layer, for transferring the common circuit
data
received through a PSTN from the non-WAP terminal, to the Internet server; and
an
interworking function (IWF) unit having a CSD protocol layer connected to the
CSD
protocol layers of each WAP terminal, and a TCP layer and an IP layer which
are
zo connected to the TCP and IP layers of each WAP server, for performing
interfacing
between each WAP terminal and each WAP server, and the non-WAP terminal and
the ISP, wherein each WAP terminal communicates with the IWF unit through a
single Internet ProtocoI/Peer-to-Peer Protocol (IP/PPP) layer included in its
own
CSD protocol layer, and the IWF unit communicates through the Internet with
each
is WAP server.
To achieve the fourth object, there is provided a communication method of a
data communications device including a plurality of WAP terminals each having
a
protocol stack in which a Circuit Switch Data service (CSD) protocol layer is
laid
under a Wireless Transaction Protocol (WTP) layer and a Wireless Datagram
3o Protocol (WDP) layer, a non-WAP terminal for generating a common circuit
data, a
plurality of WAP servers each having a protocol stack in which at least a
Transmission Control Protocol (TCP) layer and an Internet Protocol (1P) layer
are,
CA 02386585 2002-06-12
laid under a WTP layer and a WDP layer, an Internet server for providing the
non-
WAP terminal with Internet server data according to the common circuit data,
an
Internet service provider (ISP) having a public switched telephone network
(PSTN)
circuit layer, for transferring the common circuit data received through a
PSTN from
s the non-WAP terminal to the Internet server, an interworking function (IWF)
unit
having a CSD protocol layer connected to the CSD protocol layers of each WAP
terminal, and a TCP layer and an IP layer which are connected to the TCP and
IP
layers of each WAP server, for data communications between each WAP terminal
and each WAP server, the method comprising the steps of: (a) determining
whether
data input to the IWF unit is WAP data or the common circuit data; (b)
transferring
the WAP data through the Internet to the corresponding WAP server if the input
data is determined to be the WAP data in the step (a) and transferring the
common
circuit data through the ISP to the Internet server if the input data is
determined to
be the common circuit data in the step (b); (c) determining whether the data
input to
,s the IWF unit is WAP server data or the Internet server data; and (d)
transferring the
WAP server data through the Internet to the corresponding WAP terminal if the
input
data is determined to be the WAP server data in the step (c), and transferring
the
Internet server data through the PSTN to the non-WAP terminal if the input
data is
determined to be the Internet server data in the step (c), wherein each WAP
zo terminal communicates with the IWF unit through a single Internet
ProtocoI/Peer-to-
Peer Protocol (IPIPPP) layer included in its own CSD protocol layer.
BRIEF DESCRIPTION OF THE DRAWINGS
The above objects and advantages of the present invention will become more
apparent by describing in detail a preferred embodiment thereof with reference
to
2s the attached drawings in which:
FIG. 1 is a block diagram of a conventional device for data communications
between a Wireless Application Protocol (WAP) terminal and a WAP server;
FIG. 2 shows protocol stacks of each block of the conventional data
communications device;
so FIG.'3 is a detailed view of the Circuit Switch Data service protocol
(CSD(IS-
7U7) shown in FIG. 2;
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FIG. 4 is a diagram illustrating data flow in the data communications device
shown in FIG. 1;
FIG. 5 is a block diagram of a device for data communications between a
WAP terminal and a WAP server according to a preferred embodiment of the
s present invention;
FIG. 6 shows protocol stacks of each block of the data communications
device shown in FIG. 5;
FIG. 7 is a diagram illustrating data flow in the data communications device
shown in FIG. 5;
FIG. 8 is a block diagram of a device for data communications between a
WAP terminal and a WAP server according to another preferred embodiment cf the
present invention; and
FIG. 9 is a flowchart illustrating a communication method of the data
communications device shown in FIG. 8.
~s DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 5 showing a device for data communications between a
Wireless Application Protocol (WAP) terminal and a WAP server according to a
first
embodiment of the present invention, the device comprises a plurality of WAP
terminals 50, 52, ..., and an interworking function (IWF) unit 54, the
Internet 55 and
2o a plurality of WAP servers 58, 60, ...
Each WAP terminal 50, 52, ... has a protocol stack in which a Circuit Switch
Data services protocol (CSD) layer is situated below a Wireless Session
Protocol
(WSP) layer and a Wireless Datagram Protocol (WDP) layer, and generates WAP
data which is data requesting data service from each WAP server 58, 60, ...
FIG. 6
2s shows a protocol stack of one of the WAP terminals 50, 52, .... The
protocol stack
of FIG. 6 is different from that of the conventional WAP terminal of FIG. 2 in
that
only a CSD(IS-707) layer exists below the WTP and WDP layers by omitting the
IP
and PPP layers. That is, because the CSD(IS-707) layer itself includes the IP
and
PPP layers as described with reference to FIG. 3, the WAP terminal according
to
30 the present invention utilizes the IP and PPP layers of the CSD(IS-707),
without
having IP and PPP layers therein, such that there is no redundant IP and PPP
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layers unlike the conventional protocol stack. Each WAP terminal 50, 52, ...
has a
unique identification number or source IP address.
Each WAP server 58, 60, ... has a protocol stack in which a CSD layer exists
below a WTP layer and a WDP layer, and a Transmission Control Protocol (TCP)
s layer and an IP layer exist, and provides the WAP terminals 50, 52, ... with
WAP
server data according to the WAP data provided. As shown in FIG. 6, a protocol
stack of each WAP server 58, 60, ... has a corresponding structure for each
WAP
terminal 50, 52, ... The WAP server of FIG. 6 is different from the
conventional
WAP server in that it comprises the TCP layer which is not shown in the
so conventional WAP server. Each WAP server 56, 58, ... has an identification
number
or a destination IP address for each source IP address of the WAP terminals
50, 52,
The IWF unit 54 comprises a CSD protocol layer connected to each CSD
protocol layer of the WAP terminals, and TCP and IP layers each connected to
the
~s TCP and IP layers of each WAP server, to map the WAP terminals 50, 52, ...
to the
corresponding WAP servers 56, 58, ... Here, the identification number of a
specific
WAP terminal may be mapped to a destination IP address of the corresponding
WAP server, or a source IP address of the WAP terminal is mapped to a specific
mapping table value. To this end, the IWF unit 54 has a mapping table (not
shown)
zo used for connecting the identification number of a specific WAP terminal to
a WAP
server. The IWF unit 54 also includes another mapping table (not shown) which
is
used for finding the corresponding WAP terminal during reception of data from
a
WAP server. The IWF unit 54 and the WAP servers 56, 58, ... are connected
through the Internet 55.
2s FIG. 7 is a diagram illustrating data flow in the data communications
device
shown in FIG. 5.
When the WAP terminals 50, 52, ... send an Origination Message for a call
connection thereof to the IWF unit 12, the IWF unit 12 receives the
Origination
message and then sends an Origination Ack message as a confirmation of the
reception to the WAP terminals 50, 52, ... When the WAP terminals 50, 52, ...
receives the Origination Ack message, the WAP terminals 50, 52, ... being
connected to the corresponding WAP servers 58, 60, ..., the WAP terminals 50,
52,
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... send a WAP data which is service request data through the Internet 55 to
the
WAP servers 58, 60, ... After receiving the WAP data, the WAP servers 58,
60,...
send WAP server data which they retain, or data transferred from an Internet
server
(not shown) through the Internet 55 and the IWF unit 54 to the WAP terminals
50,
s 52, ... That is, the WAP terminals 50, 52, ... are directly connected to the
WAP
servers without going through an Internet service provider (ISP) using a
public
switched telephone network (PSTN).
FIG. 8 is a block diagram of a data connection device for communications
between a WAP terminal and a WAP server according to another embodiment of the
present invention.
The data connection device of FIG. 8 comprises WAP terminals 80, 82, ..., a
non-WAP terminal 84, an IWF unit 86, a PSTN 87, an ISP 88, the Internet 89, an
Internet server 90, and WAP servers 92, 94, ...
Each WAP terminal 80, 82, ... has a protocol stack in which a CSD protocol
~s layer resides below WTP and WDP layers, and generates WAP data for
requesting
data service to the WAP servers 92, 94,... Each WAP terminal 80, 82, ... has a
unique identification number or source IP address.
The non-WAP terminal 84 generates a common circuit data.
Each WAP server 92, 94, ... has a protocol stack in which TCP and IP layers
are situated below WTP and WDP layers, and provides the WAP terminals 80, 82,
... with WAP server data according to the WAP data. Each WAP server 92, 94,
...
has an identification number or a destination IP address corresponding to each
source IP address of the WAP terminals 80, 82, ...
The ISP 88 includes a PSTN circuit layer connected to a PSTN circuit layer of
is the IWF unit 86 to be described later, receives the common circuit data of
the non-
WAP terminal 82 through the PSTN 87 and transfers the received data to the
Internet server 90. The ISP 88 is one of companies providing general
communication services to a common carrier.
The Internet server 90 provides the non-WAP terminal 84 with Internet server
data in response to the common circuit data.
The IWF unit 86 includes'a CSD protocol layer, TCP and IP layers and a
PSTN circuit layer, and acts as interfaces between the WAP terminals 80, 82,
... and
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CA 02386585 2002-06-12
WAP servers 92, 94, ..., and between the non-WAP terminal 84 and the ISP 88.
The IWF unit 86 is connected through the Internet 89 to the WAP servers 92,
94, ...,
and the IWF unit 86 and the ISP 87 are connected to each other through the
PSTN
87. The CSD protocol layer is connected to each CSD protocol layer of the WAP
s terminals 80, 82, ..., and the TCP and IP layers are connected respectively
to the
TCP and IP layers of each of the WAP servers 92, 94, .... Also, the PSTN
circuit
layer is connected through the PSTN 87 to the PSTN circuit layer of the ISP
88. In
detail, when an input data is the WAP data or the WAP server data, interfacing
is
performed such that an identification number of the WAP terminal is mapped to
a
destination IP address of the WAP server, or a source IP address of the WAP
terminal is mapped to a specific mapping table value. Meanwhile, when an input
data is the common circuit data or the Internet server data, interfacing
between the
non-WAP terminal 82 and the ISP 86 is performed.
FIG. 9 is a flowchart illustrating a data communication method between a
~s WAP terminal and a WAP server according to another embodiment of the
present
invention.
One of the WAP terminals 80, 82, ... or the non-WAP terminal 84 requests
connection to one of the WAP servers 92, 94, ... or the Internet server 90
(step 902).
That is, one WAP terminal or the non-WAP terminal 84 generates a WAP data or
Zo common circuit data, respectively, and transfers the data to the IWF unit
86.
The IWF unit 86 determines whether or not the terminal that needs to be
connected in step 902 is a WAP terminal, based on the WAP data or the common
circuit data (step 904)
If the connection request terminal is a WAP terminal, the WAP terminal is
is connected through the Internet 89 to the WAP server (step 906). Meanwhile,
if the
connection request terminal is not a WAP terminal but a non-WAP terminal, the
non-WAP terminal is connected through the PSTN 87 to the ISP 88, and then to
the
Internet server 90 (step 908).
The WAP server 92 and the Internet server 90 generate WAP server data
so and Internet server data, respectively, and transfer respective data
through the
Internet 89, or the ISP 88 and the PSTN 87 to the IWF unit 86.
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The IWF unit 86 determines whether or not the input data is WAP server data
(step 912).
When the input data is from a WAP server, the data is transferred to the
WAP terminal. Meanwhile, when the input data is Internet server data, the data
is
s transferred to the non-WAP terminal 84.
The invention may be embodied in a general purpose digital computer that is
running a program from a computer usable medium, including but not limited to
storage media such as magnetic storage media (e.g., ROM's, floppy disks, hard
disks, etc.), optically readable media (e.g., CD-ROMs, DVDs, etc.) and carrier
,o waves (e.g., transmissions over the Internet).
Hence, the present invention may be embodied as a computer usable
medium having a computer readable program code unit embodied therein for
communications between a WAP terminal and a WAP server of a data
communications device including a plurality of WAP terminals having a protocol
,s stack in which a CSD protocol layer is laid under a WTP layer and a WDP
layer, a
plurality of WAP servers having a protocol stack in which a TCP layer and an
IP
layer are laid under a WTP layer and a WDP layer, and an IWF unit having a CSD
protocol layer connected to the CSD protocol layers of each WAP terminal, and
a
TCP layer and an IP layer which are connected to the TCP and IP layers of each
2o WAP server, wherein each WAP terminal communicates through a single IP/PPP
protocol layer included in its own CSD protocol layer to the IWF unit, the
computer
readable program code means in the computer usable medium comprising:
computer readable program code means for causing a computer to effect
transferring an Origination Message for a call connection from each WAP
terminal
2s to the iWF unit, and transferring an Origination ACK from the IWF unit to
the
corresponding WAP terminal in response to the Origination Message; computer
readable program code means for causing a computer to effect receiving WAP
data
which is service request data for the WAP servers from the WAP terminals, to
map
each WAP terminal to the corresponding WAP server in the IWF unit, and
3o transferring the received WAP data through the Internet to the
corresponding WAP
server; computer readable program code means for causing a computer to effect
receiving the WAP data to generate WAP server data according to the received
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WAP data in each WAP server, and transferring the WAP server data through the
Internet to the IWF unit; computer readable program code means for causing a
computer to effect receiving the WAP server data transferred in the step (c)
to map
the WAP servers to the corresponding WAP terminal in the IWF unit, and
s transferring the received WAP server data to the corresponding WAP
terminals; and
computer readable program code means for causing a computer to effect
communicating in the WAP terminals with the IWP unit through a single Internet
ProtocoI/Peer-to-Peer Protocol (IPIPPP) layer contained in each Circuit Switch
Data
service (CSD) protocol layer of the WAP terminals, for instance.
~o Also, the present invention may be embodied as a computer usable medium
having a computer readable program code unit embodied therein for
communications transferred between a WAP terminal and a WAP server of a data
communications device including a plurality of WAP terminals each having a
protocol stack in which a CSD protocol layer is laid under a Wireless
Transaction
~s Protocol (WTP) layer and a WDP layer, a non-WAP terminal for generating a
common circuit data, a plurality of WAP servers each having a protocol stack
in
which at least a TCP Payer and an IP layer are laid under a WTP layer and a
WDP
layer, an Internet server for providing the non-WAP terminal with Internet
server
data according to the common circuit data, an ISP having a PSTN circuit layer,
for
zo transferring the common circuit data received through a PSTN from the non-
WAP
terminal, to the Internet server, an IWF unit having a CSD protocol layer
connected
to the CSD protocol layers of each WAP terminal, and a TCP layer and an IP
layer
which are connected to the TCP and IP layers of each WAP server, wherein each
WAP terminal communicates through a single IP/PPP protocol layer included in
its
2s ovvn CSD protocol layer to the IWF unit, the computer readable program code
means in the computer usable medium comprising: computer readable program
code means for causing a computer to effect determining whether data input to
the
IWF unit is WAP data or the common circuit data; computer readable program
code
means for causing a computer to effect transferring the WAP data through the
3o Internet to the corresponding WAP server if the input data is determined as
the
WAP data and transferring the common circuit data through the iSP to the
Internet
server if the input data is determined to be the common circuit data; computer
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CA 02386585 2002-06-12
readable program code means for causing a computer to effect determining
whether
the data input to the IWF unit (??from) is WAP server data or the Internet
server
data; and computer readable program code means for causing a computer to
effect
transferring the WAP server data through the Internet to the corresponding to
the
s WAP terminal if the input data is determined to be the WAP server data, and
transferring the Internet server data through the PSTN to the non-WAP terminal
if
the input data is determined to be the Internet server data, for instance.
A functional program, code and code segments, used to implement the
present invention can be derived by a skilled computer programmer from the
description of the invention contained herein. .
While the present invention has been illustrated and described with reference
to specific embodiments, further modifications and alterations within the
spirit and
scope of this invention as defined by the appended claims will occur to those
skilled
in the art.
~s As described above, the data communications device according to the
present invention adopts a protocol stack in which only a single IP/PPP
protocol
layer resides in the WAP terminals and the IWF unit functions as an ISP,
providing
the following effects. First, because there is no redundancy of IPIPPP
protocol
layers in the WAP terminal, overhead is considerably reduced compared to the
2o conventional data transmission. Second, the IWF unit is directly connected
through
the Internet to the WAP server, not through the PSTN and the ISP, so that
connection time and costs can be reduced. Third, the data flow procedure is
also
simplified compared to the conventional data communications device and method
thereof.
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