Multiplex communications – Network configuration determination – In a bus system
Reexamination Certificate
1999-06-24
2004-06-22
Pham, Chi (Department: 2667)
Multiplex communications
Network configuration determination
In a bus system
Reexamination Certificate
active
06754184
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to an information processing apparatus and method, and to a distribution medium. More particularly, the present invention relates to an information processing apparatus and method which realizes communication at the optimum communication speed of a network, and to a distribution medium.
When data is transmitted among arbitrary information processing apparatuses (hereinafter referred to as “apparatuses”) connected to a bus, which are capable of transmitting data at a plurality of transmission rates, it is necessary to select a data transmission rate at which a transmitting apparatus can transmit, a receiving apparatus can receive, and further, at which, when there is another apparatus (relay apparatus) among the apparatuses, at which the relay apparatus can also operate.
FIG. 21
shows an example of a plurality of apparatuses connected to an IEEE1394 serial bus. An IRD (Integrated Receiver/Decoder)
1
to which an antenna
7
, a monitor
2
, an MD (Mini Disk) deck
3
, and digital VTRs (Video Tape Recorders)
4
to
6
are connected to each other by IEEE1394 serial buses
8
-
1
to
8
-
5
. These apparatuses, which fulfill the specifications for IEEE1394 and IEC61883 which defines AV (Audio Visual) data transmission on the IEEE1394, constitute nodes which are units to which access can be made in the IEEE1394, and have a data transmission rate at which data can be transmitted from one to the other or be received from one to the other.
The IEEE1394 serial bus is defined as the specifications of a digital interface for connecting a plurality of apparatuses. As specifications for defining the transmission rate among apparatuses connected to the IEEE1394 serial bus, three types are defined: S100 having a data transmission rate of 98.308 Mbps, S200 having a data transmission rate of 196.608 Mbps, and S400 having a data transmission rate of 392.216 Mbps. An apparatus having a high-speed data transmission rate can transmit data at a data transmission rate slower than this. For example, an apparatus which supports S400 also supports the data transmission of S200 and S100. The data transmission of S100 is possible by all apparatuses which fulfill the specifications for IEEE1394. When these apparatuses, whose upper limits of the data transmission rate are different, are connected to the IEEE1394 serial bus, the apparatus which performs data transmission must transmit data at a transfer rate at which an apparatus which performs relay can perform a relay process.
FIG. 22
shows an example of a connection of apparatuses, in which physical IDs (Identification Data) of the apparatuses shown in FIG.
21
and the specifications of the data transmission rates are indicated within the nodes. The apparatus which is connected to the IEEE1394 serial bus forms a node on the IEEE1394. A node
11
fulfilling the specifications for the data transmission rate of S400 of
FIG. 22
corresponds to an IRD
1
of FIG.
21
. In a similar manner, a node
12
fulfilling the specifications for the data transmission rate of S200 corresponds to the monitor
2
, a node
13
fulfilling the specifications for the data transmission rate of S200 corresponds to the MD deck
3
, a node
14
fulfilling the specifications for the data transmission rate of S100 corresponds to the digital VTR
4
, a node
15
fulfilling the specifications for the data transmission rate of S100 corresponds to the digital VTR
5
, and a node
16
fulfilling the specifications for the data transmission rate of S200 corresponds to the digital VTR
6
. For example, the IRD
1
fulfills the specifications for S400, the monitor
2
fulfills the specifications for S200, and there is no apparatus which relays data in between, thereby making possible communication at a data transmission rate of 196.608 Mbps. Of course, the IRD
1
and the monitor
2
are capable of performing data transmission of S100 at 98.308 Mbps.
In contrast, both apparatuses of the MD deck
3
and the digital VTR
6
fulfill the specification for S200; however, the digital VTR
4
having the specifications for S100 is present on the data transmission path. Therefore, the upper limit of the data transmission rate of the MD deck
3
and the digital VTR
6
is 98.308 Mbps which is the specification for S100.
Next, a description is given of the communication protocol of data transmission defined in IEEE1394.
FIG. 23
illustrates the structure of the functions of the IEEE1394 protocol (protocol: communication convention). The IEEE1394 protocol has a hierarchical structure of three layers: a transaction layer (Transaction Layer)
22
, a link layer (Link Layer)
23
, and a physical layer (Physical Layer)
24
. The hierarchies communicate with each other, and the respective hierarchies communicate with a serial bus management (Serial Bus Management)
21
. Furthermore, the transaction layer
22
and the link layer
23
communicate with another function block. There are four types of transmission and reception messages used for this communication: request (Request), indication (Indication), response (Response), and confirmation (Confirmation). The arrows in
FIG. 23
indicate this communication. A communication followed by “.req” at the end of the name of the arrow represents a request. In a similar manner, “.ind” represents an indication, “.resp” represents a response, and “.conf” represents a confirmation. For example, TR_CONT.req is a communication for request sent from the serial bus management to the transaction layer
22
.
The transaction layer
22
provides an asynchronous data transmission service provided to perform data transmission with another predetermined apparatus in accordance with a request from another function block, and realizes a request response protocol (Request Response Protocol) required in ISO/IEC13213. The transaction layer
22
performs an asynchronous transmission process, but does not perform an isochronous transmission process for transmitting data, such as images or sound. The data transmitted in the asynchronous transmission is transmitted, among apparatuses, by three types of transactions: a read transaction, a write transaction, and a lock transaction which are units of processing for making a request to the protocol of the transaction layer
22
. Here, the lock transaction is used to eliminate detrimental effects by split transaction (Split Transaction) composed of two or more subactions of the link layer
23
in the asynchronous communication.
The link layer
23
performs a data transmission service using acknowledge, address processing, data error confirmation, framing of data, etc. A request for an asynchronous transmission service from another function block is made to the link layer
23
. One packet transmission performed by the link layer
23
is called a subaction, and as subactions, there are two types: an asynchronous subaction, and an isochronous subaction. In the physical ID (Identification Data) which specifies a node and in an asynchronous subaction which specifies an address within the node, the node which has received the data returns an acknowledgement. In an isochronous broadcast subaction which sends data to all nodes inside the IEEE1394 serial bus, the node which has received the data does not return an acknowledgement. The data of the isochronous subaction is transmitted at a fixed cycle with a channel number being specified, and an acknowledgement is not returned.
The physical layer
24
converts a logic symbol used in the link layer
23
into an electrical signal. Furthermore, the physical layer
24
performs control so that only one node initiates data transmission by arbitration, performs re-configuration of the IEEE1394 serial bus as a result of bus reset, and performs automatic assignment of the physical ID.
The serial bus management
21
realizes the basic bus control function and provides CSR (Control&Status Register Architecture) of ISO/IEC13213. The serial bus management
21
has the functions of a node controller, an isochronous resource manager, and a bus manager.
Kato Junji
Miyano Michio
Nakano Takehiko
Frommer William S.
Frommer & Lawrence & Haug LLP
Jones Prenell
Pham Chi
Sony Corporation
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