Multiplex communications – Communication techniques for information carried in plural... – Assembly or disassembly of messages having address headers
Reexamination Certificate
2000-05-02
2004-06-15
Olms, Douglas (Department: 2661)
Multiplex communications
Communication techniques for information carried in plural...
Assembly or disassembly of messages having address headers
C370S401000, C370S229000
Reexamination Certificate
active
06751234
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a packet data transfer apparatus for radio packet communication, and especially to a TCP segment size controlling method, and radio packet system control which depends on user data occurrence condition.
In
FIG. 5
, a protocol stack between two communication terminals that conduct a TCP data transfer on radio packet communication is shown. Here, it is assumed that each layer is taking a share in a function in accordance with an OSI reference model.
A radio link is provided between a packet data transfer apparatus
10
and a radio base station
20
, and provides radio packet communication by a layer
2
and less than or equal to that. A wire link is provided between the radio base station
20
and a gateway device
30
, and the layer
2
and less than or equal to that have unique protocols within a net.
A wire link is provided between the gateway device
30
and a packet data transfer apparatus
40
, and the layer
2
and less than or equal to that have other protocols within a net. A case can be considered, in which an ethernet is used here.
It is assumed that, in a layer
3
, an IP is used between the packet data transfer apparatus
10
and the packet data transfer apparatus
40
. It is assumed that, in a layer
4
, a TCP is used between the packet data transfer apparatus
10
and the packet data transfer apparatus
40
.
A user data to be transferred, which occurs in a user application on the packet data transfer apparatus
10
is shaped into a TCP segment in the TCP (layer
4
), is shaped into an IP packet in the IP (layer
3
), to which an IP header is added, and is converted into a frame in the layer
2
, which is unique to radio packet communication, and thereafter, is sent by means of radio in a layer
1
.
The radio frame which was sent by means of radio from the packet data transfer apparatus
10
is received by the radio base station
20
, and is transferred to the gateway device
30
by using a unique transfer method in a net protocol.
In the gateway device
30
, the IP packet is reconstructed, and the IP packet is transferred through a net such as an ethernet, and is transferred to the packet data transfer apparatus
40
.
In the packet data transfer apparatus
40
, a user data is taken out from the reconstructed TCP segment, and is delivered to a user application on the packet data transfer apparatus
40
.
In
FIG. 6
, a block diagram of a packet data transfer apparatus for conducting a TCP data transfer at a radio packet by means of a prior art is shown.
A TCP segment generating section
402
receives a transmitted user data and generates a TCP segment having a size of which an upper limit is a maximum segment size, and delivers it to an IP packet generating section
302
. The IP packet generating section
302
adds an IP header to the TCP segment which was received from the TCP segment generating section
402
, and generates an IP packet, and delivers it to a radio packet generating/transmitting section
202
.
The radio packet generating/transmitting section
202
reconstructs the IP packet into a unique frame in radio packet communication, and delivers it to a radio transmission and reception processing section
102
.
The radio transmission and reception processing section
102
conducts radio transmission of the transmitted radio frame from the radio packet generating/transmitting section
202
through a transmission and reception antenna
101
. Also, the radio transmission and reception processing section
102
takes out a received radio frame from the transmission and reception antenna
101
, and delivers it to a radio packet receiving section
203
.
The radio packet receiving section
203
reconstructs a radio packet from the radio frame, and delivers it to an IP packet receiving section
303
.
The IP packet receiving section
303
reconstructs the radio packet which was received from the radio packet receiving section
203
into an IP packet, and delivers it to a TCP segment receiving section
403
.
The TCP segment receiving section
403
reconstructs a TCP segment from the IP packet, and outputs a received user data.
A radio packet transmission and reception controlling section
201
controls the radio packet generating/transmitting section
202
and the radio packet receiving section
203
based on information from the radio transmission and reception processing section
102
. Also, the radio packet transmission and reception controlling section
201
conducts control in accordance with a control data addressed to the radio packet transmission and reception controlling section
201
, which was received from the radio base station
20
, and at the same time, transmits the control data to a radio packet transmission and reception controlling section (not shown) of the radio base station
20
.
The transmitted control data from the radio packet transmission and reception controlling section
201
is transmitted and processed from the radio packet transmission and reception controlling section
201
through the radio packet generating/transmitting section
202
like the user data.
In the same manner, a received control data from a radio packet transmission and reception controlling section (not shown) of the radio base station
20
is received and processed in the radio transmission and reception processing section
102
like the user data, and thereafter, is delivered to the radio packet transmission and reception controlling section
201
through the radio packet receiving section
203
.
An IP packet transmission and reception controlling section
301
controls the IP packet generating section
302
and the IP packet receiving section
303
. Also, the IP packet transmission and reception controlling section
301
notifies a TCP segment transmission and reception controlling section
401
of a maximum size (MTU; Maximum Transport Unit) of an IP packet during initial setting of a data transfer.
The TCP segment transmission and reception controlling section
401
controls the TCP segment generating section
402
and the TCP packet receiving section
403
. Also, during a data transfer, the TCP segment transmission and reception-controlling section
401
conducts transmission and reception of a control data with a TCP segment transmission and reception controlling section (not shown) that is other party to communicate with, and controls a confirmation response, resending, transmission and reception rate and so forth of a TCP segment. Further, the TCP segment transmission and reception controlling section
401
exchanges a data with a control interface
404
for transferring a TCP data to a user application.
In
FIG. 7
, a flowchart of maximum segment size control of a TCP by means of a prior art is shown.
First, after initialization, a maximum segment size (MSS; Maximum Segment Size) of a TCP is set only one time when a TCP connection is established (A-
1
). This is calculated based on the MTU which was notified from the IP packet transmission and reception controlling section
301
.
Next, in case that a transmitted user data exists (A-
2
), a segment is generated (A-
3
), and segment sending processing is conducted (A-
4
).
In
FIG. 8
, a data flow between layers until a user data is divided and processed into a size to be transferred by means of a radio frame is shown.
A user data is delivered to the radio packet generating/sending section
202
under condition that a TCP header is added thereto in a TCP layer and an IP header is added thereto in an IP layer. In the radio packet generating/sending section
202
, a unique overhead (shown as “OH” in
FIG. 8
) in this layer is added thereto, and it is divided into radio frame unit.
Here, in a radio frame
1
, a radio packet to be transferred is being divided into just n. Although, in a radio frame
2
, the radio packet to be transferred is being divided into three, since a data in a high position, which fills up a third radio frame, does not exist, padding of a useless data (a zero value and so forth) is conducted.
In
FIG. 9
, a time line of a TCP data t
Dickstein , Shapiro, Morin & Oshinsky, LLP
NEC Corporation
Olms Douglas
Wilson Robert W.
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