JP2000078206A - Connection control system in fiber channel connection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the number of traffics which can conduct simultaneous communication by selecting either of connection-type communication or connectionless-type communication from the type whether an FC terminal is an FC server or an FC client terminal and from the transmission direction of an FC frame. SOLUTION: A cell inputted from an input terminal Ain is received by an ATM interface 12, the received cell is reassembled in an ATM/FC converter 14, and is restored to an IP packet. An IP heater is checked, and the IP address of a destination FC terminal is obtained. The inside of a terminal type table 15 is retrieved, and a destination terminal address D-ID is obtained. This is written into a destination address field in an FC header with the ATM/FC converter 14, and an FC frame is prepared. Then, it is sent to an FC interface 11. A controller 16 obtains the type of the destination FC terminal from the terminal type table 15, based on the D-ID and causes either connectionless-type communication or connection-type communication to be executed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a connection between a fiber channel (FC) network and a wide area network such as an ATM network.
In particular, the present invention relates to a connection control method of an FC connection device that connects an FC network and a wide area network.

[0002]

2. Description of the Related Art FC specifications are based on ANSI (America).
n National Standard Insti
Tute) It is determined based on the FC standard established by X3T11. Conventionally, when an FC terminal accommodated in an FC network transmits a large amount of data to a partner terminal connected to the wide area network via the FC network, the FC connection device, and the wide area network, a connection called a service class 1 is established with the other terminal. Type communication. In the case of such connection-type communication, the entire band is occupied by the data transmission on the end-to-end link which is the connection path between the FC terminal and the FC connection device.

[0003]

Conventionally, for example, while two FC terminals are communicating via a network, the entire bandwidth of the used link is occupied by the communication. We had to wait until the communication was completely finished and the link was free. Also, even if there is a time during which data is not transmitted during communication, other FC terminals cannot use the link by interrupting the time. Here, the FC terminal refers to a terminal that uses the FC by performing the FC communication protocol. Specifically, it is a workstation, a computer, or the like that communicates with another terminal via the installed FC communication protocol.

That is, the FC accommodated in the FC network
When transmitting data from a plurality of FC servers, which are terminals, to a plurality of client terminals connected to another network (broadband network) via an FC connection device at the same time, a connection is first established with the FC connection device. Another FC server must wait until the communication of the established FC server ends, and as a result, there is a problem that it takes a long time for the other FC server to finish transmitting data. Also, in a conversational communication system in which data is transmitted from the FC server to the partner client terminal, a request for the next data transmission is returned from the partner client terminal to the FC server, the FC server with the connection always transmits FC data. Is not continuing, F
The C server transmits the FC sequence composed of several to several tens of FC frames in a burst manner, and thereafter, the FC server side transmits the data until a packet requesting the next data transmission arrives from the client terminal. Do not send at all. Conventionally, there has been a problem that the non-transmission time of such a frame is relatively long and the connection is kept open during this time, so that the line utilization efficiency is reduced.

Similarly, when a plurality of FC client terminals, which are FC terminals, simultaneously receive data from a plurality of servers connected to another network, the FC terminal that has first established a connection with the FC connection device is also required. Until the connection of the client terminal ends, the other FC client terminals have to wait, so that it takes a long time to receive all the data. In addition, the FC client terminal that has established a connection does not always receive FC data, but receives an FC sequence composed of several to several tens of FC frames in a burst manner, and thereafter, Until the FC sequence is received, the FC client terminal does not receive any data. Conventionally, the non-reception time of such a frame exists for a relatively long time, and the connection is kept open during this time, so that there is a problem that the line utilization efficiency is similarly reduced.

[0006] Therefore, the present invention provides a method for transmitting data from a plurality of FC servers in an FC network to a wide area network having a communication protocol other than the FC network simultaneously in a conversational communication system. An object of the present invention is to increase the number of traffics that can be simultaneously communicated by preventing the connection from being occupied and giving transmission opportunities equally to all FC servers. In addition, the present invention is configured such that, when data is transmitted from a network having a communication protocol other than the FC network to the FC client terminal via the FC connection device, a specific FC client terminal occupies a connection with the FC connection device. By giving equal reception opportunities to all FC client terminals
An object of the present invention is to increase the number of traffics capable of simultaneous communication.

[0007]

In order to solve such a problem, the present invention provides a first network (FC network) accommodating a plurality of FC terminals and a second network accommodating a plurality of non-FC terminals. Connected to the other network (ATM network) and forwards a packet transmitted from one terminal to the other terminal, a table in which the type of the FC terminal is registered in advance, and a table transmitted from the FC terminal. When the received packet is received, the type of the transmission FC terminal is identified based on the registered contents of the table, and the connection-type communication for establishing a link with the transmission FC terminal and the connectionless communication not establishing the link according to the identification result. A first selecting means for selecting any one of the communication modes, and receiving a packet from the non-FC terminal to the FC terminal, A second selection unit for identifying the type of the receiving FC terminal to be transmitted based on the registered contents of the table, and selecting one of the connection-type communication and the connectionless-type communication in accordance with the identification result; When connection-type communication is selected by each selection means, a connection is established and released each time a predetermined number of frames of a plurality of frames are transferred. In addition, a control frame for changing each communication mode of the FC terminal is transmitted between the FC terminal and the FC connection device, and the FC connection device transmits a packet transmitted in any connection type from the FC terminal. Is received, the type of the transmission FC terminal is identified based on the registered contents of the table, and when the communication mode of the transmission FC terminal based on the identification result and the connection type do not match, the transmission FC terminal based on the identification result is identified. A change means is provided for transmitting a control frame for instructing a change to a connection type corresponding to a communication mode to a transmission FC terminal and changing the control frame. In addition, an FC server and an FC client terminal are provided as FC terminals, and an FC
The server and the FC client terminal are registered as FC terminal types, and the first selecting means selects the communication mode as connection-type communication when the transmission FC terminal is an FC server, and sets the transmission FC terminal as an FC client terminal. In some cases, the communication mode is selected as connectionless communication, while the second selecting means is that the receiving FC terminal
When the server is a server, the communication mode is selected as connectionless communication, and when the receiving FC terminal is an FC client terminal, the communication mode is selected as connection-type communication.

[0008] Therefore, if the FC terminal is an FC server or FC
From the type of the client terminal and the transmission direction of the FC frame, it is determined whether the data packet of the upper application or the control bucket is included in the payload of the FC data frame, and the connection type communication and the connectionless type are accordingly determined. One of the communications is selected. That is, since a data packet is generally carried in a large number of FC frames, connection-type communication that guarantees the frame order, has an acknowledgment (ACK), and enables high-speed communication is selected. On the other hand, a control packet is generally carried in a small number of FC frames of about one frame to several frames, so connectionless communication that does not require overhead such as connection setup / release is selected.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of the present invention, and shows a configuration of an FC connection device 1 disposed between an FC network 2 described later and an ATM network 3 which is another network. It is. In FIG. 1, the FC connection device 1
FC interface 11, ATM connected to switch
ATM interface 1 connected to network 3
2. AT frame from FC interface 11
An FC / ATM converter 13 for converting into an M cell, an ATM / FC converter 14 for restoring an ATM cell from the ATM interface 3 into an FC frame, and a terminal type table recording the types of FC terminals connected to the FC network 2 are shown in FIG. The stored terminal type table 15 comprises a controller 16 for determining the connection type of the FC interface 11 to be either connection type or connectionless type. Here, the connection type is an abbreviation of a connection oriented type.

FIG. 2 is a block diagram showing the configuration of a system in which the FC connection device 1 is provided. In FIG. 2, the FC switch 21 connected to one end of the FC connection device 1
23, two FC servers 31 (# 1) and 32 (# 2) and two FC client terminals 41 (# 1) and 42 (# 2) as FC terminals. Connected. Here, the type of FC terminal is F
It is divided into C servers 31 (# 1) and 32 (# 2) and FC client terminals 41 (# 1) and 42 (# 2).
An ATM network 3 is connected to the other end of the FC connection device 1.
Is connected to the ATM network 3, and the client terminals 61 (# 1) and 62 (# 2) and the server 51
(# 1) and 52 (# 2) are connected.

Now, the FC which is provided between the FC network 2 and the ATM network 3 and is constructed as described above.
The operation of the connection device will be described. F transmitted from the FC terminal via the FC switch in the FC network 2
The C frame is received at the input terminal Fin and guided to the FC / ATM converter 13. In the FC / ATM converter 13, the F
It decodes the FC header of the C frame and detects the address of the sending FC terminal. This is the S_ID (Source Id
entifier) and is reported to the controller 16 as the address A1. In the terminal type table 15, all FC terminals belonging to the FC network 2 are registered in advance as FC server or FC client terminals. The controller 16 sends the address A1 (S_I
When D) is input, the terminal type table 15 is searched based on the address A1, and it is determined whether the terminal corresponding to the address A1 is an FC server or an FC client terminal.
Then, according to the type, the controller 16 sets the mode setting M of the FC interface 11 to one of the connection type and the connectionless type, negotiates with the transmitting FC terminal via the FC switch, and sets Use the same connection type between the two.

For example, if it is determined that the S_ID is the FC server, the controller 16 sends the F_ID transmitted therefrom.
The C frame is regarded as a data packet, and connection type communication is set. Specifically, service class 1 is adopted. At the time of the service class 1, each FC switch configuring the FC network operates as a cross point switch equivalent to a direct connection between a specific FC terminal and the FC connection device 1 via a dedicated line. In the case of the connectionless type, processing such as a change of the destination line based on the result of decoding the destination address in the FC header is required in the FC switch. However, in the case of the connection type, such switching operation is unnecessary because it is fixed. High-speed data transfer processing becomes possible.

Conversely, if the S_ID is an FC client terminal, the FC frame from the FC client terminal is
It regards it as a control packet for a data request or the like to the opposite terminal and sets connectionless communication. Specifically, service class 2 or service class 3 is used. In service class 2 or 3, the selection of the outgoing line of the FC switch and the internal connection processing between the incoming line and the outgoing line occur based on the destination address in the FC header. However, the frequency of the control packet is extremely low as compared with the data packet, and the number of FC frames for transmitting the control packet is also small depending on the application. One FC frame is about 2K
Since it is sufficient that a byte packet can be transmitted and the length of the control packet itself is generally shorter, it can be transmitted in one frame, and the processing delay is small and does not hinder high-speed communication.

There are two types of FC frames, a data frame and a control frame.
It is transmitted using a C data frame. If the FC header is decoded, the type of the FC frame can be known, but it cannot be identified whether the payload is a data packet or a control packet of a higher-level application. Therefore, attribute information on whether the transmitting terminal and the receiving terminal of the FC frame are a server or a client terminal is required.

Regarding data transfer, when the FC connection device 1 transfers data to the FC client terminal connected to the FC network 2, the FC connection device 1 selects the connection type. FC connection device 1 connects to FC server
When transferring a frame, it is regarded as a control packet and set to a connectionless type.

The FC / ATM converter 13 converts the input FC frame into ATM cells,
Send to 2. An example of this conversion method will be described. FC
The FC header of the frame is removed, and the payload is taken out. The payload is generally IP (Internet P
protocol) packet. This payload is segmented and converted into cells. The ATM interface 12 transmits the cell from the output terminal Aout to the ATM network 3. VP corresponding to destination terminal address
I and VCI refer to those written in the terminal type table 15 in advance.

Here, the terminal type table 15 includes a portion for acquiring VPI and VCI from the IP address of the destination-facing ATM terminal, and a D_ID from the IP address of the destination FC terminal.
(Destination Identifier). The FC / ATM converter 13 decodes the header of the IP packet and
The P address is detected, and the corresponding VPI and VCI are acquired with reference to the table 15.

Next, the operation when an ATM cell is received from the ATM network 3 will be described with reference to FIG. The cell input from the input terminal Ain is received by the ATM interface 12 and the ATM / FC converter 14
Pass to The ATM / FC converter 14 reassembles the received cell and restores the original IP packet. The IP header of this IP packet is checked to obtain the IP address of the destination FC terminal. This destination IP address is stored in the terminal type table 1
5 to obtain D_ID which is the destination FC terminal address. These related addresses are all written in the terminal type table 15 in advance.
The ATM / FC converter 14 writes this D_ID in the destination address field in the FC header to create an FC frame, and sends it to the FC interface 11.

The controller 16 acquires the type of the destination FC terminal from the terminal type table 15 based on the D_ID. If the destination FC terminal is an FC server, the controller 16 regards the FC frame as a control packet and controls the FC interface 11. Perform connectionless communication. In the case of an FC client terminal, the FC frame addressed thereto is regarded as a data packet, and the FC interface 11 is controlled to perform connection-type communication. FC interface 11
Communicates with the FC terminal via the FC network 2 using the type of connection specified by the controller 16, and
The C frame is transmitted from the output terminal Fout to the destination FC terminal.

As described above, the FC connection device 1 determines whether the data packet of the upper application or the control bucket is included in the payload of the FC data frame based on the type of the FC terminal as the FC server or the FC client terminal and the transmission direction of the FC frame. It is determined which one is mounted, and the connection type communication or the connectionless type communication is determined according to the result of this determination. Here, since a data packet is generally carried in a large number of FC frames, the connection type communication is a communication type that guarantees the frame order, has an acknowledgment (ACK), and can perform high-speed communication. On the other hand, since control packets are generally carried in a small number of FC frames of about one frame to several frames, connectionless communication is performed without the need for overhead such as connection setup and release.

Next, when the FC terminal starts communication with the FC connection device 1, the type of connection determined by the FC connection device 1 does not match the type initially selected by the FC terminal. The method for causing the error will be described with reference to FIG. FIG. 6 shows a configuration in which a control FC frame generator 17 is provided in the FC connection device 1 of FIG. In FIG. 6, when the controller 16 detects the mismatch of the connection type, the controller 16 generates an FC control frame requesting to match the type determined by the FC connection device 1, and performs FC control to the FC terminal that transmitted the FC data frame. Send a frame.

Although the ANSI standard does not define this frame, the FC control frame allows many reserves and guarantees that the vendor can freely define and use it. Therefore, an FC control frame that specifies a service class is defined, and means for interpreting and executing the FC control frame are provided in both the FC terminal and the FC connection device 1 in advance. Specifically, for example, an execution function for a new FC control frame is added to the driver software. The FC control frame for this is F
R_CTL (Routing Counter) in the C header
ol) field, it can be defined by allocating codes reserved by ANSI. For example,
Basic Link Service (BasicLink Se)
5) codes, such as NOP and RMC, are defined in the command, but others are undefined reserved codes. One method is to allocate one of the undefined reserve codes.

A connection changing method using the FC control frame defined as described above will be described with reference to a sequence diagram of FIG. First, FC network 2
Through the service class i (i = 1, 2, 3,
), The FC data frame is transmitted. Then, the FC connection device 1 sets the terminal type table 15
, The type of the FC terminal is detected, and the type of the connection is determined according to the method described above. If it is determined that the determined connection type does not match the connection of the service class i, the FC connection apparatus 1 sets the service class j corresponding to the connection to be selected.
It is determined that (i ≠ i) should be changed.

The FC connection device 1 immediately creates an FC control frame designating the service class j, and
The request is transmitted to the FC terminal via the network 2 to change the connection. Incidentally, the service class 1 is a connection type, and the service classes 2 and 3 are a connectionless type. Service class 2 requires an ACK (confirmation frame), but service class 3 does not. Either one can be used as the connectionless type to select.

When the FC terminal receives this FC control frame, it immediately changes the service class from the previous service class i to the newly specified service class j,
At this point, an FC data frame is transmitted. Later,
Each time an FC terminal is set to continue transmitting FC data frames with a new service class j,
There is no need to send control frames. When logging in to the FC connection device 1 for the first time, the FC terminal negotiates with the FC connection device 1 so that all service classes can be used. During communication, from the FC connection device 1
This service FC frame is used to specify which service class to use.

When the FC connection frame 1 transmits the FC control frame specifying the type of service class to the FC terminal as described above, the FC terminal communicates with the specified service class. With this configuration, the FC terminal matches the connection type determined by the FC connection device. For example, when the FC server first transmits a connectionless FC frame, the FC connection device immediately transmits an FC control frame to the FC server so as to switch to the connection type communication, and thereafter the FC server communicates in this direction. To connection-based communication. Conversely, when an FC frame is transmitted from the FC client terminal in a connection type, the F
The C connection device 1 immediately transmits an FC control frame to the FC client terminal so as to switch to connectionless communication, and thereafter, the FC client terminal switches communication in this direction to connectionless communication.

Next, referring to FIG.
A system in which conversational communication is executed between an ATM network 3 and another network via the FC connection device 1 will be described. In FIG. 2, as described above, two FC servers 31 (#
1), 32 (# 2) and two FC client terminals 4
1 (# 1) and 42 (# 2) are connected as FC terminals. Here, it goes without saying that the number of FC terminals is arbitrary. As the types of FC terminals, there are various databases such as a huge amount of image data, and FC servers 31 (# 1) and 32 (# 2) which read data from the database and transmit the data to a remote terminal requesting the data. ,Conversely,
For example, the data can be divided into two parts: FC client terminals 41 (# 1) and 42 (# 2) that receive image data and display it on the screen or screen.

Generally, the type and configuration of the peripheral hardware of the FC terminal and the type of the peripheral device are fixedly determined by the software such as the installed driver. These FC terminals are FC switches 22 and 23
To configure the FC network 2 which is the first network. Then, the FC switch 21 connected to the FC switches 22 and 23 is connected via the FC connection device 1 to, for example, an ATM which is a second network as shown in FIG.
Connected to the network 3, this ATM network 3
Are connected to client terminals 61 (# 1) and 62 (# 2) and servers 51 (# 1) and 52 (# 2). Here, the terminals communicating with each other are:
The FC server 31 (# 1) and the client terminal 61 (#
1), FC server 32 (# 2) and client terminal 62
(# 2), the server 51 (# 1) and the FC client terminal 41 (# 1), and the server 52 (# 2) and the FC client terminal 42 (# 2).

The terminals 51, 52, 61 and 62 connected to the ATM network 3
It is not necessary to have This is because, as described with reference to FIG. 1, the FC connection device 1 transmits the IP packet with the FC header removed to the ATM network 3. AT
This is because when receiving the M cell, the FC connection device 1 adds an FC header. Communication in the FC network 2 is performed using FC frames, and the FC terminals 31, 32,
Communication between 41.42 and the FC connection device 1 includes a connection type and a connectionless type as shown in FIG.

Next, the flow of data will be described with reference to FIGS. FIG. 3 is a timing chart showing a transmission frame and a reception frame of the FC servers 31 and 32 shown in FIG. 2, and shows the operation of the first main part of the present invention.
Hereinafter, the FC servers 31 and 32 will be referred to as FC server #, respectively.
1 and # 2 and the client terminals 61 and 62 will be described as client terminals # 1 and # 2, respectively. FIG. 3 (a),
The transmission data from the FC servers # 1 and # 2 shown in (b) is connection-type communication, and links L11 and L12, respectively.
Through the FC switch 22 in the FC network 2, and reaches the FC connection device 1 via the FC switch 21. This FC data frame is converted into a cell by the FC connection device 1, passes through the ATM network 3, and reaches the client terminals # 1 and # 2 via the links L11 'and L12', respectively. Upon receiving the data cell, the client terminals # 1 and # 2 transmit the next data request packet in the cell format in the direction opposite to the above-described direction by the upper layer protocol. This is the FC connection device 1 following the reverse route described above.
Reaches

In this case, the FC connection device 1 performs connectionless communication and transmits an FC frame carrying a data request packet to the FC servers # 1 and # 2. Here, since this data request packet has no data portion, it is generally small-sized data. That is, this FC frame is about 2k
Since the payload length is a byte, the FC frame for this purpose is as short as one frame, for example. Therefore, FC
The connection device 1 performs connectionless communication, and does not have a data frame on the link between the FC connection device 1 and the FC switch 21 and quickly transfers the data at a vacant timing where no connection is established. As a result, such data request packets are represented by the symbols in FIGS.
, Are transmitted to the FC servers # 1 and # 2, and received by the FC servers # 1 and # 2.
You.

Further, since the FC server # 1 and the FC server # 2 cannot simultaneously transmit data, the FC connection device 1 establishes a connection with one of the FC servers, and
1 which is one block (one lump) of the C data frame
The sequence is received, and ACKs corresponding to the sequence are returned at the timings shown in FIG. Therefore, the connection of the FC link in one sequence of the FC connection device 1 is, as shown in FIG.
This is until data is received from # 2 and ACK (acknowledgment signal) for this is returned to each FC server # 1, # 2. Here, as an example of a data block, one IP
A packet corresponds to one sequence. It is also possible to transmit a plurality of IP packets in one sequence, and it is assumed that the IP packets are one sequence for the sake of simplicity, although this does not hinder the description.

The maximum length of an IP packet is 64 kbytes, whereas the maximum length of an FC data frame is about 2 kbytes, so that a maximum of 32 frames (64 k ÷ 2 k) constitute one sequence. End notification of the sequence (End_of_Sequen) is added to the FC header of the last frame of the sequence.
Since ce) is written, the FC connection device 1 transmits a connection release request to the FC servers # 1 and # 2 when detecting this notification. The connection release request is
There are various methods, for example, NOP (No Opera)
)) to the FC connection device 1
To the FC servers # 1 and # 2, and the EOFdt (End_of_F)
ram Disconnect_Terminat
This can be done by using e). In this case, a connection release request may be added to an ACK frame, which is a confirmation signal for received data, and transmitted to the FC server. In addition, the direct RMC (Remove connection)
This is also possible by transmitting the connection release control frame n).

If the propagation delay of the ATM network 3 is large, the arrival of the data request bucket from the opposite terminal is delayed, and the FC server # 1 or # 2 waits several mS to several tens mS after the data transmission is completed. It may reach # 1 and # 2. If the FC server # 1 maintains the connection during this time, the FC link cannot be used by the FC server # 2, so that the use of the link is inefficient. Therefore, as soon as the data transmission of the FC server # 1 or # 2 is completed, the ACK is returned from the FC connection device 1 to the FC server # 1 or # 2 to release the connection. When the control packet (data request packet) arrives, the data request packet is immediately transferred to the corresponding FC server # 1 or # 2 without establishing a connection.

The FC server # that has received the data request packet and has completed preparation for transmitting the next data quickly.
When data is transmitted from # 1 or # 2, the FC connection device 1 establishes a connection with the corresponding FC server. SOFc1 is added to the delimiter indicating the frame start of the FC data frame transmitted from the FC server # 1 or # 2.
(Start_of_Frame Connect C
connection1) is used to execute connection-type communication. As described above, for example, when the FC server # 1 is performing data transmission using the FC link, the FC connection device 1 sends the data to the FC server # 1 as soon as the data transmission is completed.
The connection is released by returning the CK, and the data request packet is immediately transferred to the corresponding FC server # 1 without establishing a connection, for example, at the point of time in FIG. 3B when the data request packet arrives. Things.
As a result, in FC server # 2, FIG.
Using the link released for the data request packet at the time (d), data can be transmitted to the opposite terminal as shown in FIG. 3 (c).

Since the round-trip delay of the ATM network 3 differs according to the accommodation location of the ATM terminals 51, 52, 61 and 62, a data request is sent from the ATM network 3 to the FC connection device 1 in a time band in which a connection is established.
May be reached. In such a case, the data request frame is made to wait in the FC connection device 1 until the connection becomes free, and is transferred to the corresponding FC server preferentially immediately after the connection is released.

Next, data transmission in the direction opposite to the data flow of FIG. 3 will be described with reference to FIGS. FIG. 4 is a timing chart showing a reception frame, a transmission frame, and an acknowledgment frame of the FC client terminals 41 and 42 shown in FIG. 2 and shows the operation of the second main part of the present invention. Hereinafter, the FC client terminals 41 and 42 are referred to as FC client terminals # 1 and # 2,
52 will be described as servers # 1 and # 2, respectively. AT
Data from the servers # 1 and # 2 connected to the M network 3 passes through the ATM network 3 and reaches the FC connection device 1. In this case, the FC connection device 1 establishes a connection with the FC clients # 1 and # 2, and transmits this data to the FC client terminal # via the links L21 and L22.
1 and # 2. As a result, the FC client terminals # 1 and # 2 receive data at the timings of FIGS. 4A and 4C, respectively. In this case, the FC client terminals # 1 and # 2 receive the acknowledgment FC frames (ACK frames) indicating that the data has been normally received at the timings of time,.
Send to

The delivery confirmation FC frame is terminated by the FC connection device 1, and does not reach the servers # 1 and # 2. Since data transfer is connection-type communication, the transmission order of FC frames is guaranteed in the FC switch in the FC network 2, and high-speed transmission is possible because all the bands are used. In data transfer, FC client terminals # 1,
Since connection-type communication is performed between # 2 and the FC connection device 1, communication is performed only with one of the FC client terminals # 1 and # 2. For example, when a connection is established with FC client terminal # 1, F
The FC client terminal # 1 uses the entire band of the link from the C connection device 1 to the FC client terminal # 1 through the FC switch in the FC network 2, and the FC client terminal # 2 cannot use it. Therefore, the FC connection device 1 releases the connection for each data block,
As shown in FIG. 4E, when data to the FC client terminal # 1 is received from the ATM network 3, a connection is established with the FC client terminal # 1, while
When the data to the C client terminal # 2 is received from the ATM network 3, a connection is established between the client terminal # 2 and the FC client terminal # 2.
1 and # 2 are used equally.

The FC connection device 1 reconstructs an IP data packet from the received ATM cell. An IP packet has a maximum length of 64 kbytes, and an FC frame has a maximum of about 2 kbytes.
It is divided into C frames and transmitted to FC clients # 1 and # 2. That is, FC frames for one IP packet are collected and transmitted as one sequence. By writing a connection release request to the FC header of the last frame of this sequence, it is notified that the connection is to be released, and the connection with the FC client terminal # 1 or # 2 is released.

At the timing shown in FIGS. 4B and 4D, no connection is established with any FC client terminal.
The next data request packet is transmitted from # 1, # 2 through the FC switch in the FC network. The FC connection device 1 sends this to the opposite server # via the ATM network 3.
1 and # 2. When the opposite servers # 1 and # 2 receive this data request packet, they transmit the next data to the FC client terminals # 1 and # 2 via the ATM network 3, and the FC connection device 1 relays this data. To the FC client terminals # 1 and # 2. Upon receiving the data, the FC client terminals # 1 and # 2 immediately return an ACK at the timings shown in FIG. The FC connection device 1 releases the connection with the FC client terminals # 1 and # 2 at the timing of receiving this.

Subsequently, FC frames for the next data request from the FC client terminals # 1 and # 2 are transmitted.
This next data request is transmitted after the FC client terminals # 1 and # 2 process the previously received FC data, and the time has elapsed since the ACK was received. That is, if the data received from the server is, for example, image data, the FC client terminal restores this to the original image,
Processing time such as display on the screen is required. Therefore, since the FC client terminal does not immediately request the next data after receiving the received data, it is useless to establish a connection up to this point.
When the ACK is received, the connection is released.

Next, a third embodiment of the present invention will be described with reference to FIGS.
Will be described. The timing chart of FIG.
In this example, the FC server # 1 and the FC client terminal # 1 accommodated in the C network 2 independently communicate with the opposite terminals accommodated in the ATM network 3. Here, the operation of the FC server # 1 and the FC client terminal # 1
Are independent, and are the same as the respective timing charts shown in FIGS. 3 and 4 described above. That is, the FC server # 1 and the FC client terminal # 1 respectively
As shown in (a), (c) and (e), the FC connection device 1
A data transfer is performed by establishing a connection at different timings between the two. Then, every time one sequence is completed, an ACK is returned at the timing shown in FIGS. 5B and 5D, and the connection is released. Further, the data request frame is transmitted in a short time at the timing shown in FIGS. 5B and 5D where no connection is established.

As described above, a plurality of FC servers and a plurality of FC client terminals are mixed and accommodated in the FC network 2, and the FC server and the FC client terminals are connected to another network (ATM network 3). When performing communication with the FC connection device, the FC connection device 1 performs connection-type communication for data transfer, and establishes and releases a connection every time a data block is transmitted and received. As a result, a communication opportunity can be equally provided to all terminals that perform communication. Further, the transfer order of FC frames is guaranteed, and the FC switch in the FC network 2 can operate at high speed, so that the data transfer time can be reduced. Also, FC connection device 1
By performing connectionless communication for a control packet such as an FC data request packet, the control packet can be quickly transferred without generating an overhead for establishing and releasing a connection.

[0044]

As described above, according to the present invention, a network is connected between a first network accommodating a plurality of FC terminals and a second network accommodating a plurality of non-FC terminals. An FC connection device that forwards a packet transmitted from one terminal to another terminal has a table in which the type of the FC terminal is registered in advance. When a packet transmitted from the FC terminal is received, the type of the transmission FC terminal is set in the table. Identify based on registered contents and send FC according to identification result
While selecting either the connection-type communication for establishing a link with the terminal or the connectionless communication for not establishing the link,
Upon receiving a packet to the terminal, the type of the receiving FC terminal that receives the packet is identified based on the registered contents of the table, and one of the connection-type communication and the connectionless-type communication is selected according to the identification result. In addition, when the connection-type communication is selected, the connection is established and released every time a predetermined number of frames of the packet composed of a plurality of frames are transferred. Occupation of the connection with the connection device can be avoided, so that transmission opportunities can be equally given to all FC servers. In addition, it is possible to prevent a specific FC client terminal, which is a receiving FC terminal, from occupying a connection with the FC connection device, and thus it is possible to equally provide a reception opportunity to all FC client terminals. Also, when the FC connection device receives a packet transmitted from the FC terminal in any connection type, the FC connection device identifies the type of the transmission FC terminal based on the registered contents of the table, and determines the type of the transmission FC terminal based on the identification result. If the communication mode and the connection type do not match, the transmission FC terminal is instructed to change to the connection type corresponding to the communication mode of the transmission FC terminal based on the identification result. The communication mode suitable for the terminal can be set appropriately. When the transmitting FC terminal is an FC server, the communication mode is selected as connection-type communication. When the transmitting FC terminal is an FC client terminal, the communication mode is selected as connectionless communication.
When the receiving FC terminal is an FC server, the communication mode is selected as connectionless communication, and when the receiving FC terminal is an FC client terminal, the communication mode is selected as connection-type communication.
A communication mode suitable for the data amount of the terminal can be selected.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a first configuration of an FC connection device to which the present invention has been applied.

FIG. 2 is a block diagram showing a configuration of a communication system in which the FC connection device of FIG. 1 is provided.

FIG. 3 is a time chart showing a first operation of the communication system.

FIG. 4 is a time chart showing a second operation of the communication system.

FIG. 5 is a time chart showing a third operation of the communication system.

FIG. 6 is a block diagram showing a second configuration of the FC connection device.

FIG. 7 is a sequence diagram illustrating an example of a connection type change setting by the FC connection device in FIG. 6;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... FC connection apparatus, 2 ... FC network (1st network), 3 ... ATM network (2nd network), 11 ... FC interface, 12 ... ATM interface, 13 ... FC / ATM converter, 14 ... ATM
/ FC converter, 15 ... Terminal type table, 16 ... Controller, 21-23 ... FC switch, 31, 32 ... FC
Server, 41, 42 ... FC client terminal, 51, 5
2. Server, 61, 62 client terminals.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H04Q 3/00 H04L 13/00 305B F-term (Reference) 5K002 DA05 DA09 FA01 5K030 GA01 HA10 HC01 HD01 JL03 KA04 LB01 LB18 LB19 MB09 5K033 AA02 CB06 DA05 DB22 5K034 AA01 EE02 EE11 HH01 HH02 HH61 JJ24 LL01 LL02

Claims (3)

[Claims] An apparatus is connected between a first network accommodating a plurality of fiber channel terminals and a second network accommodating a plurality of non-fiber channel terminals, and transmits a packet transmitted from one terminal to the other. In the fiber channel connection device for transferring to the terminal of the type, a table in which the type of the fiber channel terminal is registered in advance, and when a packet transmitted from the fiber channel terminal is received, the type of the transmission fiber channel terminal is determined based on the registered contents of the table. First selection means for selecting one of a connection-type communication for establishing a link with the transmission fiber channel terminal and a connectionless communication for not establishing the link in accordance with the identification result; Receives packets from non-fiber channel terminals to fiber channel terminals Then, the type of the receiving fiber channel terminal that receives the packet is identified based on the registered contents of the table, and one of the connection-type communication and the connectionless-type communication is selected according to the identification result. A connection means for establishing and releasing a connection every time a predetermined number of frames of the packet comprising a plurality of frames are transferred when connection-type communication is selected by each of the selection means. Connection control method in the connection device. 2. The fiber channel connection device according to claim 1, wherein a control frame for changing each communication mode of the fiber channel terminal is transmitted from the fiber channel connection device between the fiber channel terminal and the fiber channel connection device. Upon receiving a packet transmitted from the Fiber Channel terminal in any connection type, identifies the type of the transmission Fiber Channel terminal based on the registered contents of the table, and determines the type of the transmission Fiber Channel terminal based on the identification result. When the communication mode and the type of the connection do not match, a control frame instructing to change to the type of connection corresponding to the communication mode of the transmission Fiber Channel terminal based on the identification result is transmitted to the transmission Fiber Channel terminal and changed. That there is a change means Connection Control for Fiber Channel connection device according to symptoms. 3. The fiber channel terminal according to claim 1, further comprising a fiber channel server and a fiber channel client terminal as the fiber channel terminals, and wherein the table shows the type of the fiber channel terminal by the fiber channel server and the fiber channel client terminal. The first selection means selects the communication mode as connection-type communication when the transmission fiber channel terminal is a fiber channel server and when the transmission fiber channel terminal is a fiber channel client terminal While selecting the communication mode as connectionless communication, the second selecting means selects the communication mode as connectionless communication when the receiving fiber channel terminal is a fiber channel server. And selecting the communication mode as connection-type communication when the receiving fiber channel terminal is a fiber channel client terminal.