JPH1127338A - Communication device and communication method - Google Patents

Abstract

(57) [Summary] [Problem] To improve transmission efficiency by opening many communication ports in a short time. SOLUTION: A first transmission word of an open command includes a code K28.5, D17.4, Dxx. x, D31.7
Are arranged, and the 128 bits of the second to fifth transmission words are used as a bit map area. That is, for example, the 31st to 0th bits of the second transmission word have port addresses of 0 to 31.
Are assigned to (corresponding to) each port, and in the same manner, a port is assigned to each bit of the bitmap area. The above open command is transmitted by setting only the bit corresponding to the port to be opened in the bitmap area to 1 and setting the remaining bits to 0.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication device and a communication method, and more particularly, to a communication device and a communication method capable of performing efficient communication.

[0002]

2. Description of the Related Art As one of communication standards, for example, ANS
There is a Fiber Channel developed by I (American Standards Association). The “fiber” of Fiber Channel is “fi”
bre ”and“ fib ”in a so-called optical fiber.
er ".

[0003] Devices that perform communication using Fiber Channel are called nodes, and each node transmits and receives data through a port (communication port). In the Fiber Channel, the cable connecting the ports is not particularly limited. For example, even if the cable is a fiber cable or a coaxial cable,
Also, a twisted pair cable may be used.

Further, Fiber Channel is one of the serial communication systems, but has a higher transmission speed and a longer transmission distance than other serial communication systems. In addition, TCP /
IP (Transmisson Control Protocol / Internet Protocol)
l) Other protocols can be loaded,
Furthermore, since the scalability of the connection of the devices is high, it is expected to be applied to data transmission between various devices in the future.

[0005] Here, in Fiber Channel, the transmission speed is currently 128 Mbps (bit per second), 2
56 Mbps, 512 Mbps, and 1 Gbps are specified, and expansion to 2 Gbps and 4 Gbps is planned in the near future. Further, the transmission distance varies depending on the transmission speed.
m to 10km, 10m for coaxial cable
To about 100 m, and about 50 m to 100 m for the twisted pair cable, respectively.

[0006] A fiber channel port has one transmitter for transmitting data and one receiver for receiving data.
Broadly speaking, point-to-point
t) Topology and arbitrated loop (arbitrate
d loop) topology.

In the point-to-point topology, only two ports are used, and one transmitter is connected to the other receiver, and one receiver is connected to the other transmitter. In this topology, it is necessary that the transmission speed, the transmission medium (the cable connecting them), the protocol, and the like of the two ports match.

The arbitrated loop topology has three
The above-mentioned ports are configured, and a transmitter of a certain port and a receiver of another port are connected to each other, thereby forming a ring-shaped network.

That is, FIG. 6 shows an arbitrated loop topology with four ports A to D, in which the transmitter of port A and the receiver of port B are replaced by the transmitter of port B and the receiver of port C. The transmitter of port C and the receiver of port D are connected to each other, and the transmitter of port D and the receiver of port A are connected to each other. In the arbitrated loop topology, at present, 12
Up to seven ports can be connected.

[0010] Since the point-to-point topology is composed of two ports, data transmission / reception only needs to be performed on ports other than the own port. May be performed through a port that is not the target of the operation.

That is, in FIG. 6, for example, when data is transmitted from port A to port C, data addressed to port C is transmitted from the transmitter of port A to the receiver of port B. When the port B receives the data addressed to the port C at the receiver, the port B transmits the data as it is from the transmitter to the port C receiver. In this way, the port C receives the data addressed to itself from the port A. In this case, the port B operates as a so-called repeater that simply transmits the data received by the receiver from the transmitter.

By the way, in the Fiber Channel standard,
± 10 for transmitter clock of each port
A jitter (deviation) of 0 ppm (parts par million) is allowed. In the Fiber Channel, data reception is performed in synchronization with a clock obtained from the data so that the receiver can reliably receive data even if the transmitter clock has jitter as described above. .

That is, a receiver of a certain port operates in synchronization with a clock of a transmitter of another port connected thereto. Therefore, for example, in the arbitrated loop topology shown in FIG. 6, the transmitter of port A and the receiver of port B are different from the transmitter of port B and the receiver of port C as shown by the dotted line in FIG. , And the transmitter of port C and the receiver of port D are synchronized with the same clock, respectively.

Hereafter, the operation clocks of the transmitter or the receiver constituting the same port are referred to as the transmitter clock or the receiver clock, respectively, as appropriate. The receiver clock is equal to the transmitter clock of the transmitter of the other port to which the receiver is connected.

[0015]

As described above, the receiver of a certain port operates in synchronization with the transmitter clock of the transmitter of the other port connected thereto, and the transmitter clock is ± 100 pp.
Because a jitter of m is allowed, there is a maximum of 200 ppm deviation between the transmitter clock and the receiver clock at a given port.

Then, between two clocks having a deviation of 200 ppm, a shift (clock skew) of one clock occurs for every 5000 clocks.

On the other hand, in the arbitrated loop topology, when data is transmitted from a certain port to another port, the port transmitting the data has a right to use the bus (arbitrated loop) prior to transmitting the data. Need to get. This struggle for the right to use the bus is called arbitration.

After the port for transmitting data has acquired the right to use the bus by arbitration, it is necessary to open the port as the transmission destination of the data and then transmit the data.

In the fiber channel, commands for opening ports connected in an arbitrated loop topology include OPNyx, OPNyy, and OPN.
A so-called order set such as fr, OPNyr, etc. is defined.

Here, OPNyy is used when performing full-duplex communication, and OPNyy is used when performing half-duplex communication. OPNfr is used when opening all ports constituting the arbitrated loop topology, and OPNyr is used when opening a plurality of ports.

FIG. 8 shows the format of the order set OPNyr specified by the Fiber Channel.

The order set OPNyr is composed of one transmission word (TW) as shown in FIG. Here, one transmission word is an amount of data transmitted and received in one clock in the fiber channel, and is currently 4 bytes (32 bits).

In the fiber channel, 8B / 10B converted data is transmitted / received in order to reduce transmission errors. First byte of order set OPNyr (3rd byte)
In the 1st to 24th bits, a special code called K28.5, which is a code after 8B / 10B conversion, is arranged. The special code is used for word synchronization when reproducing parallel data from serial data.

In the second byte (23rd to 16th bits) from the beginning, the code after 8B / 10B conversion is D
A special code called 17.4 is placed. this is,
Indicates that the order set is an order set for OPN. 3rd byte (15th to 8th bits)
Is the port address AL_PD of the port to be opened
Is arranged. The 4th byte (last 1 byte) (7th to 0th bits) contains the code after 8B / 10B conversion,
A special code called D31.7 is arranged. This indicates that a plurality of ports are opened (there are ports to be opened).

In the fiber channel, data called a frame is transmitted and received in addition to the order set as described above. Further, when order sets and frames are not transmitted and received, data called a fill word is transmitted and received.

That is, as described above, the receiver of a certain port operates in synchronization with the clock of the transmitter of the other port connected to it, so that it is necessary to constantly transmit and receive some data. Therefore, when an order set or a frame is not transmitted / received, data called a fill word (Fill Word) is transmitted / received. Here, the fill word includes, for example,
Data called idol (IDLE) and AR (ARB) are defined. Idle is for filling in between order sets and between frames, and ARB is for obtaining a right to use a bus (communication network). Therefore, when no order set or frame transmission / reception is performed, basically, idle transmission / reception is performed.

As described above, when a port operates as a repeater, data received by a receiver of the port is transmitted as it is by a transmitter of the port. However, the receiver clock and the transmitter clock are not the same. In other words, since there is a maximum deviation of 200 ppm between them, transmission of data received in synchronization with the receiver clock at the port operating as a repeater in synchronization with the transmitter clock can be performed for a long time. If they are performed continuously, normal data transmission / reception may not be performed.

That is, in the Fiber Channel, as described above, one transmission word is transmitted per clock. Accordingly, when there is a deviation of, for example, 200 ppm between the receiver clock and the transmitter clock, as described above, one clock shift occurs for every 5000 clocks. Will fail.

Therefore, in order to prevent data transmission / reception failure due to such clock skew (clock deviation), a fill word (particularly idle) is inserted before and after a frame or order set. Here, in Fiber Channel, after transmission of a frame or order set,
It is defined to transmit at least six transmission word fill words.

Therefore, when data is transmitted to a large number of ports, there is a problem that the transmission efficiency deteriorates.

That is, when transmitting data to a large number of ports, it is necessary to open the large number of ports. Here, as described above, in the arbitrated loop of the fiber channel, a maximum of 127 ports can be connected.

To open a number of ports, the O
It is necessary to transmit the PNyr order set as many times as the number of the ports. Then, each time that transmission is made, as described above, at least six transmission words must be inserted.

Therefore, for example, in a case where an arbitrated loop topology is constituted by 127 ports, for example, when 125 ports are opened, at least an OPNyr order set of one transmission word and six transmissions are set. A total of 7 transmission words, including the fill word of words, must be transmitted 125 times, ie,
At least 875 (= 7 × 125) transmission words of data must be transmitted, which will take a very long time.

As a result of spending a long time in opening the port, the transmission efficiency deteriorates.

The present invention has been made in view of such a situation, and aims to improve data transmission efficiency.

[0036]

According to a first aspect of the present invention, there is provided a communication apparatus comprising: an open command in which a plurality of bits corresponding to a plurality of communication ports are added to a code instructing to open a communication port; A transmission means is provided which transmits only a port corresponding to a communication port to be opened to a predetermined value.

According to a second aspect of the present invention, there is provided a communication method for opening a communication command in which a plurality of bits corresponding to a plurality of communication ports are added to a code for instructing opening of a communication port. It is characterized in that only the port corresponding to the port is transmitted with a predetermined value.

According to a third aspect of the present invention, in the communication apparatus, when the open command is a code for instructing to open a communication port, a plurality of bits corresponding to a plurality of communication ports are added. It is provided with confirmation means for confirming whether or not a bit corresponding to itself among a plurality of bits has a predetermined value, and processing means for performing processing for opening a communication port in accordance with a confirmation result of the confirmation means. Features.

According to a fifth aspect of the present invention, in the communication method according to the first aspect, when the open command is a code for instructing to open a communication port, a plurality of bits corresponding to a plurality of communication ports are added. A communication port is opened when a bit corresponding to itself among a plurality of bits has a predetermined value.

[0040] In the communication apparatus according to the first aspect, the transmitting means may include an open command in which a plurality of bits corresponding to a plurality of communication ports are added to a code for instructing opening of a communication port. Only the communication port corresponding to the communication port to be opened is set to a predetermined value and transmitted.

In the communication method according to the second aspect, an open command in which a plurality of bits corresponding to a plurality of communication ports are added to a code instructing to open a communication port is opened among the plurality of bits. Only the communication port corresponding to the communication port is set to a predetermined value and transmitted.

According to a third aspect of the present invention, when the open command is a code for instructing to open a communication port, a plurality of bits corresponding to a plurality of communication ports are added to the code. Confirms whether or not a bit corresponding to itself among a plurality of bits in the open command has a predetermined value, and the processing means performs processing for opening a communication port in accordance with a result of the confirmation by the confirmation means. Has been made.

In the communication method according to the fifth aspect, when the open command is a code for instructing to open a communication port, a plurality of bits corresponding to a plurality of communication ports are added. The communication port is opened when a bit corresponding to itself out of the plurality of bits in has a predetermined value.

[0044]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below, but before that, the correspondence between each means of the invention described in the claims and the following embodiments will be clarified. For this reason, the features of the present invention are described as follows by adding the corresponding embodiment (however, an example) in parentheses after each means.

That is, the communication device according to the first aspect is a communication device that opens a communication port of a communication partner and performs communication via the communication port. Transmission means for transmitting an open command to which a plurality of bits corresponding to a plurality of communication ports are added with a predetermined value of only a plurality of bits corresponding to a communication port to be opened (for example, the program shown in FIG. 3). Processing steps S1 and S2).

According to a third aspect of the present invention, there is provided a communication apparatus for performing communication by opening a communication port in response to an open command for opening a communication port,
In the case where the open command is a code for instructing to open a communication port with a plurality of bits corresponding to a plurality of communication ports added thereto, a receiving means for receiving the open command (for example, the receiver 13 shown in FIG. 1) , 23, 33, 43, etc.) and checking means for checking whether a bit corresponding to itself among a plurality of bits in the open command has a predetermined value (for example, processing step S11 of the program shown in FIG. 4) )
And a processing means (for example, processing step S13 of the program shown in FIG. 4) for opening a communication port in accordance with the result of the confirmation by the confirmation means.

In the communication device according to the present invention, when the communication port is opened, a changing means for changing a bit corresponding to itself out of a plurality of bits (for example, processing step S14 of the program shown in FIG. 4). Is further provided.

Of course, this description does not mean that each means is limited to those described above.

FIG. 1 shows a network system to which the present invention is applied (a system refers to a system in which a plurality of devices are logically assembled, and it does not matter whether the devices of each configuration are in the same housing or not). 1 shows a configuration example of one embodiment.

In this embodiment, one server 1 and three terminals 2 to 4 are connected, for example, a LAN (Lo
A network system as a cal area network is configured.

That is, the server 1 has, for example, a port 11 for performing communication control based on Fiber Channel. The port 11 has a transmitter 12 for transmitting data and a receiver 13 for receiving data.

The terminals 2 to 4 also have ports 21, 31, and 41, respectively, which are configured in the same manner as the port 11.
That is, the ports 21, 31, and 41 are connected to the transmitter 12
Transmitters 22, 32, and 42 configured similarly to
And a receiver 23 configured similarly to the receiver 13,
33 and 43 respectively.

Then, the transmitter 12 and the receiver 2
3, the transmitter 22 and the receiver 33, the transmitter 32 and the receiver 43, and the transmitter 42 and the receiver 13, respectively, thereby forming an arbitrated loop topology.

In the network system configured as described above, for example, when the server 1 transmits data to a plurality of terminals 2 to 4, the server 1
Is an open command that adds a plurality of bits corresponding to a plurality of ports (hereinafter, appropriately referred to as a bitmap area) to a code for instructing to open a port,
Of the plurality of bits, only the bit corresponding to the port to be opened is set to 1, for example, and the remaining bits are set to, for example, 0, and transmitted. That is, for example, the terminal 2
When the ports 21 and 31 of the terminals 2 and 3 are opened, the bit corresponding to the ports 21 and 31 in the bit map area is set to 1 and the remaining bits are set to 0. Send.

The transmission of the open command is performed by the server 1
This is performed by the transmitter 12 of the port 11 at. Then, the open command is transmitted to the receiver 23 of the port 21, the transmitter 22, the terminal 3 of the terminal 2.
, Receiver 33 of port 31 and transmitter 3
2. Via the receiver 43 and the transmitter 42 at the port 41 of the terminal 4, the data is finally received by the receiver 13 at the port 11 of the server 1.

On the other hand, in the terminals 2 to 4, the transmitted open command is received by the receivers 23, 33, and 43, respectively, and the bit corresponding to itself in the bit map area in the open command is 1 or not. Is checked. Then, when the bit corresponding to itself is 1, the port is opened.

Among the terminals 2 to 4, the one that opened the port changes the bit corresponding to itself in the bitmap area in the open command from, for example, 1 to 0, and changes the open command after the change to the own. From the transmitter to the receiver connected to it.

If the bit corresponding to the terminal is not set to 1, the terminal transmits the received open command as it is from its own transmitter to the receiver connected thereto.

After transmitting an open command from the transmitter 12 of the port 11 to the receiver 23 of the port of the terminal 2, the server 13 transmits the open command transmitted from the transmitter 42 of the port 41 of the terminal 4 to the receiver 13. Upon reception, by referring to the bitmap area, it is recognized whether a port to which data is to be transmitted has been opened.

That is, as described above, in the terminals 2 to 4 whose ports are opened, the bit corresponding to the terminal 2 in the bit map area is changed from 1 to 0. Therefore, by referring to the bitmap area, it can be recognized whether or not the port to which data is to be transmitted has been opened.

In the server 1, data is transmitted to the terminals 2 to 4 whose ports are opened.

As described above, only the bit corresponding to the port to be opened in the bit map area is set to 1 and the port is opened by the open command in which the remaining bits are set to 0. Can be opened by one open command. As a result, especially when many ports are opened, the transmission efficiency can be improved.

In the terminals 2 to 4 whose ports are opened, the bit corresponding to itself in the bit map area is changed from 1 to 0. Therefore, it can be easily confirmed whether the port is opened.

Next, FIG. 2 shows a configuration example (format) of the open command.

In this embodiment, the open command is composed of, for example, five transmission words.

In the first transmission word of the open command, a code for instructing to open a port is arranged. Here, except for the 15th to 8th bits, for example, the order shown in FIG. The configuration is the same as that of the set OPNyr. That is, since the open command belongs to the order set OPNyr, the first transmission word of the open command is configured similarly to the order set OPNyr except for the 15th to 8th bits. .
Bits 15 to 8 contain specific values Dxx. To distinguish them from other order sets. x (code after 8B / 10B conversion) is arranged.

The 128 bits of the second to fifth transmission words of the open command are used as a bit map area. That is, for example, the 31st to 0th bits of the second transmission word are assigned (corresponding) to ports having port addresses (port IDs) of 0 to 31, respectively. Similarly, the 31st to 0th bits of the third transmission word correspond to ports having port addresses of 32 to 63, and the 31st to 0th bits of the fourth transmission word correspond to port addresses of 6 to 6.
Ports 4 to 95 are respectively assigned.

The 31st to 1st bits of the fifth transmission word have the port address of 96 to 1
26 ports, and the 0th
The bits are reserved areas (reserved bits).

That is, in the Fiber Channel, the maximum number of ports that can constitute the arbitrated loop topology is 127 at present. Therefore, in the present embodiment, even when the arbitrated loop topology is configured with the maximum number of ports, the bitmap area is set to a value of 127 bits or more so that each port can be specified. , And is composed of 128 bits which is the minimum value of an integral multiple of 32 bits (one transmission word). In this case, one bit is left, but in FIG. 2, the 0th bit of the fifth transmission word is reserved as the remaining one bit.

In the case of opening a port, the above open command sets only the bit (assigned) corresponding to the port to be opened in the bitmap area to 1, and sets the remaining bits to 1 Sent to zero.

Next, an open order set transmission process for transmitting the above open command and an open order set reception process for receiving the open command will be described.

Here, it is assumed that the open command is transmitted from the server 1 and received by the terminals 2 to 4, for example. That is, it is assumed that the server 1 performs an open order set transmission process, and the terminals 2 to 4 perform an open order set reception process.

In the open order set transmission processing, first, in step S1, an open command bitmap area is created. That is, in the bit map area in the open command as shown in FIG. 2, only the bit corresponding to the port to be opened is set to 1, and the remaining bits are set to 0. Then, step S2
Then, the open command described in FIG. 2 having the bitmap area created in step S1 is transmitted, and the process proceeds to step S3.

In step S3, it is determined whether the open command transmitted by itself has been transmitted through another port as described above. If it is determined that the open command has not been transmitted, the process proceeds to step S3. Return. If it is determined in step S3 that the open command transmitted by itself has been transmitted via another port, the process proceeds to step S4, and the open command is opened by referring to the bitmap area in the open command. The confirmed port is confirmed, and the process ends.

After performing the above-described open order set transmission processing, the server 1 starts transmitting data only to the opened ports.

On the other hand, upon receiving the open command, the terminals 2 to 4 perform open order set reception processing.

That is, as shown in the flowchart of FIG. 4, first, in step S11, it is determined whether or not the bit corresponding to its own port is 1 in the bit map area in the received open command. You. If it is determined in step S11 that the bit corresponding to the own port is not set to 1, the process skips steps S12 to S14 and proceeds to step S15, where the other ports connected to the transmitter of the own port The received open command is transmitted to the port receiver as it is, and the process ends.

If it is determined in step S11 that the bit corresponding to the own port is 1, the flow advances to step S12 to determine whether the own port is in a state capable of receiving data. Is determined.
If it is determined in step S12 that the own port is not in a state capable of receiving data, steps S13 and S14 are skipped and step S15 is performed.
Proceed to. In step S15, the received open command is transmitted as described above, and the process ends.

On the other hand, if it is determined in step S12 that the own port is in a state capable of receiving data, the process proceeds to step S13, the port is opened, and the process proceeds to step S14. In step S14, the bit corresponding to its own port in the bitmap area is 1
Is changed to 0, and the process proceeds to step S15. in this case,
In step S15, the open command whose bitmap area has been changed as described above is transmitted to the receiver of another port connected to the transmitter of its own port, and the process ends.

By using the open command as described above, it is possible to open a large number of ports in a shorter time than in the conventional case.

That is, for example, as described above, when opening 125 ports, conventionally, as shown in FIG.
As shown in (A), the order set OPNyr must be transmitted to each of the 125 ports, and between each order set OPNyr, at least a fill word of 6 transmission words (particularly, idle) must be inserted. Must. As a result, it takes at least 875 transmission words to open 125 ports.

On the other hand, in the case of using the open command, as shown in FIG. 5B, it is sufficient to transmit an open command of 5 transmission words and a fill word of 6 transmission words.
It is possible to open 125 ports in a time corresponding to 11 (= 5 + 6) transmission words, that is, about 1/7 of the conventional time.

As described above, the case where the present invention is applied to communication based on the Fiber Channel standard has been described. However, the scope of the present invention is not limited to this. Further, the present invention is applicable to both serial communication and parallel communication.

In this embodiment, the server 1
Has been described above, data can be transmitted from any of the terminals 2 to 4 to the remaining terminals and the server 1.

The present invention is applicable to a case where one port is opened, but is particularly useful when a large number of ports are opened.

Further, in this embodiment, terminals 2 to 4
Of those, the one that opens the port changes the bit corresponding to itself in the bitmap area from 1 to 0, so that the server 1 checks whether the port is opened. , This confirmation
In addition, for example, it is also possible to make the terminal transmit information indicating that the port has been opened separately from the open command.

Further, in the present embodiment, the bit map area of the open command is constituted by four transmission words (FIG. 2). The size of the bit map area is not limited to this. It can be determined based on the number of ports constituting the arbitrated loop topology, and the like.

Further, in the present embodiment, a port address as an absolute value is assigned to each bit of the bitmap area so as to correspond to the port. However, each bit of the bitmap area is associated with the port. The association can also be made relatively, for example, relatively. That is, for example, based on a port that transmits an open command, a port having a receiver connected to the transmitter of the port is associated with the first bit of the bitmap area, and thereafter, similarly, Each bit can be associated with a port.

[0089]

According to the communication apparatus of the first aspect and the communication method of the second aspect, a plurality of bits corresponding to a plurality of communication ports are added to a code instructing to open a communication port. An open command is transmitted with a predetermined value of only a plurality of bits corresponding to a communication port to be opened. Therefore, for example, a large number of ports can be opened in a short time.

The communication device according to claim 3 and the communication device according to claim 5
According to the communication method described in (1), a communication port is opened when a bit corresponding to itself among a plurality of bits in an open command has a predetermined value. Therefore, for example, a large number of ports can be opened in a short time.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration example of an embodiment of a network system to which the present invention has been applied.

FIG. 2 is a diagram showing a format of an open command.

FIG. 3 is a flowchart illustrating an open order set transmission process.

FIG. 4 is a flowchart illustrating an open order set receiving process.

FIG. 5 is a diagram for explaining a time required to open a port 125;

FIG. 6 is a diagram illustrating a connection mode of ports according to an arbitrated loop topology.

FIG. 7 is a diagram for explaining operation clocks at ports connected in an arbitrated loop topology.

FIG. 8 is a diagram showing a format of an order set OPNyr.

[Explanation of symbols]

1 server, 2 to 4 terminals, 11 ports, 1
2 transmitter, 13 receivers, 21 ports, 22 transmitters, 23 receivers, 3
1 port, 32 transmitters, 33 receivers, 41 ports, 42 transmitters, 43
Receiver

Claims (5)

[Claims] 1. A communication device for opening a communication port of a communication partner and performing communication through the communication port, wherein a code instructing to open the communication port includes a plurality of codes corresponding to the plurality of communication ports. A communication apparatus, comprising: a transmission unit that transmits an open command to which a bit is added with only a value corresponding to a communication port to be opened among the plurality of bits being a predetermined value. 2. A communication method for opening a communication port of a communication partner and performing communication via the communication port, wherein a code instructing to open the communication port includes a plurality of codes corresponding to a plurality of communication ports. A communication method, characterized in that an open command to which bits are added is transmitted with a predetermined value of only a plurality of bits corresponding to a communication port to be opened. 3. A communication device for performing communication by opening said communication port in response to an open command for opening a communication port, wherein said open command instructs to open said communication port. In a case where a plurality of bits corresponding to a plurality of communication ports are added to a code, a receiving unit that receives the open command, and a bit corresponding to itself among the plurality of bits in the open command has a predetermined value. A communication device, comprising: a confirmation unit for confirming whether the communication port has been opened; and a processing unit for performing a process of opening the communication port in accordance with a confirmation result of the confirmation unit. 4. When the communication port is opened,
4. The communication device according to claim 3, further comprising a changing unit configured to change a bit corresponding to itself among the plurality of bits. 5. A communication method for performing communication by opening said communication port in response to an open command for opening a communication port, wherein said open command instructs to open said communication port. In a case where a plurality of bits corresponding to a plurality of communication ports are added to a code, when a bit corresponding to itself among the plurality of bits in the open command has a predetermined value, the communication port is set to a predetermined value. A communication method characterized by being opened.