Electrical computers and digital processing systems: multicomput – Computer-to-computer data routing – Prioritized data routing
Reexamination Certificate
1998-05-29
2004-05-25
Jaroenchonwanit, Bunjob (Department: 2143)
Electrical computers and digital processing systems: multicomput
Computer-to-computer data routing
Prioritized data routing
C709S251000, C370S461000
Reexamination Certificate
active
06742046
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
Present invention relates to an information network system and terminal apparatus and, more particularly, to an information network system connected to a plurality of terminals such as multimedia, a work station, a personal computer and a printer.
2. Related Art
Conventionally, an information network system has been constructed as shown in FIG.
17
.
In
FIG. 17
, reference numeral
49
denotes a transmission path such is a coaxial cable. Numerals
50
to
54
denote terminals connected to the transmission path
49
.
FIG. 17
shows only the construction of the terminal
52
, however, the other terminals have the same construction.
In the terminal, numeral
61
denotes a data processor for generating transmission data and processing received data;
60
, an output unit for transferring the transmission data generated by the data processor
61
to transmitter
56
, which outputs the input data from the output unit
60
to the transmission path
49
;
55
, a receiver for receiving data from the transmission path
49
;
59
, an input unit for transferring the data received by the receiver
55
to the data processor
61
;
57
, a collision detector for detecting a collision with another terminal and outputting a detection result to the data processor
61
; and
58
, a carrier detector for detecting transmission from another terminal and outputting a detection result to the data processor
61
.
In the conventional information network system having the above construction, a terminal which is going to perform data transmission confirms unused status of the transmission path
49
by the carrier detector
58
, and transfers transmission data generated by the data processor
61
to the transmitter
56
via the output unit
60
. The transmitter
56
converts the data into a predetermined signal and outputs the signal onto the transmission path
49
.
If the collision detector
57
detects a collision, the terminal transmits a predetermined jam signal from the transmitter
56
and stands by in accordance with a predetermined back off algorithm, thereafter, retries transmission again. If no collision occurs, it transmits the transmission data.
In the above conventional information network system, the receiver
55
of all the terminals always monitors data on the transmission path
49
, and in a case where a reception address added to the data on the transmission path
49
corresponds to the address of its own terminal, receives the data and transfers it to the input unit
59
.
However, the conventional system has following problems.
In the conventional system, the right of use of the transmission path
49
is assigned to a terminal which has started transmission earlier than other terminals in a “first come, first served” manner regardless of priority or emergency. Accordingly, the other terminals have to wait for the termination of transmission of the terminal that has obtained the use of the transmission path
49
.
Further, in the conventional system, the transmission path
49
has not been efficiently used since data outputted onto the transmission path
49
is transmitted through the whole transmission path
49
, and at this time, the transmission path
49
is used for only one transmission. For example, in
FIG. 18
, when the terminal
50
transmits data to the terminal
52
, the data from the terminal
50
is also transmitted to the terminals
54
and
56
which are not the receiver terminals of the transmission. In this case, as a result, the terminals
54
and
50
cannot perform transmission.
As a moving image network system, an optical ring network having a structure as shown in
FIG. 19
is considered. This network comprises video camera
65
as a moving image signal source, display
66
as a moving image output device and terminal
67
connected to the video camera
65
and the display
66
. The terminal
67
has a function of encoding a moving image signal from the video camera
65
into a desired digital signal and outputting the signal to network interface
68
and a function of decoding a digital signal from the network interface
68
and inputting the decoded signal into the moving image output device.
The network interface
68
has a function of examining slots of a frame which circulates on the optical ring network and inserting a digital signal outputted from the terminal into an empty channel and a function of reading out a digital signal from a channel for the terminal. Optical fiber
69
is employed as a transmission path for an optical signal transmitted on the optical ring network.
However, the above optical ring network has a drawback that, as one channel is monopolistically assigned to the plural slots for one moving image signal transmission, a terminal which newly transmits a moving image transmission request when all the slots are used has to wait until one of the slots becomes empty, thus degrading response to transmission request.
To solve the above problem, sequentially changing the channel use in a predetermined time unit can be considered to realize transmission of moving image signals more than the number of the channels. In this case, however, the transmission of a moving image signal is halted at any time when the right of use of channel is lost.
Further, in the above optical ring network, transmission capacity of one channel is fixed. For this reason, if a transmission moving image is a lower resolution image or a transmission data amount is small, a part of the transmission capacity is wasted, thus degrading the usage efficiency of the transmission path in the entire network.
To solve this problem, the present applicant has proposed U.S. patent application Ser. No. 07/924,629 filed on Aug. 4, 1992 prior to the present invention.
SUMMARY OF THE INVENTION
The present invention has been made in consideration of the aforementioned problems and drawbacks of the conventional systems, and has as its object to provide a network system and terminal apparatus which has high usage efficiency of a transmission path.
Another object of the present invention is to provide a network system and terminal apparatus which transmits transmission data without delay.
Further, another object of the present invention is to provide a terminal apparatus for a network system having high usage efficiency of a transmission path.
According to the present invention, the foregoing objects are attained by providing an information network system comprising: a plurality of terminals; and a plurality of transmission media forming a transmission path by connecting the plurality of terminals, wherein the plurality of terminals respectively have: a memory for relaying transmission information; and transmission means for transmitting the transmission information in accordance with priority order, wherein said system transmits the transmission information on the transmission path formed by the transmission media in a predetermined direction.
It is another object of the present invention to provide a network system and terminal apparatus for a moving image.
Further object of the present invention is to provide a network system and terminal apparatus which has high response to moving image transmission request.
It is another object of the present invention to provide a network system and terminal apparatus which transmits properly compressed moving image data corresponding to the status of a transmission path.
According to the present invention, the foregoing objects are attained by providing a moving image network system, in which a plurality of terminals are connected to each other via a bi-directional transmission path, for inserting moving image data into a plurality of slots and transmitting/receiving the moving image data, comprising: means for generating transmission load information regarding transmission of the moving image data on the transmission path; means for transmitting/receiving the transmission load information in a direction opposite to a transmission direction of the moving image data; coding means for encoding the moving
Mashimo Hiroshi
Yamamoto Mitsuru
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