JP3200800B2 - Connection system of packet communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a connection system between a first network having both a connection-oriented communication function and a connectionless communication function and a second network having a connectionless communication function. .

[0002]

2. Description of the Related Art Conventionally, Fiber Channel
In a communication system using a switch fabric of an ann.), as service classes, a class 1 (connection-oriented communication) in which connection is set and then transfer is performed, and a class 2 and 3 (connection) in which connection setting is not required. Communication). Class 1 for communication with long transfer time such as large capacity information transfer
However, class 2 or class 3 is used for short transfer time communication.
Is suitable. Note that A between fiber channel terminals
Class 2 exchanges CK frames and class 3 does not exchange ACK frames. Here, for simplicity of description, they are collectively described as connectionless types.

Although the communication system shown in FIG. 1 shows an embodiment of the present invention, the configuration of the whole communication system is the same as that shown in FIG. explain. The fiber channel frame flowing on the fiber channel transmission medium is encoded by an 8B10B code defined as a transmission code of the fiber channel, and has a frame format as shown in FIG. In FIG. 5, SOF 21 indicates the start of a frame defined by a 4-word code string.
(Start of Frame) delimiter, 22 is a frame header of 24 words, 23 is a variable length data field of a maximum of 2112 bytes, and 24 is a 4-word CRC for error checking.
A code (Cyclic Redundancy Check) 25 is an EOF (Enof) indicating the end of a frame defined by a 4-word code string.
d of Frame) delimiter. Here, a unit obtained by encoding 1-byte data by the 8B10B code is called a word.

In order to set a class 1 connection, as shown in FIG.
A connection setting request frame to which an Fc1 (SOF Connect Class 1) delimiter is added is transmitted from the terminal requesting the connection setting. The connection between the ports is specified by the destination port address and the transmission port address in the frame header. Then, an ACK frame to which the SOFn1 (SOF Initiate Class1) delimiter is added as the SOF delimiter is returned from the partner terminal in response to the connection opening request frame. Thus,
The connection is set. In order to release the connection, EOFdt is used as the EOF delimiter.
(EOF Disconnect-Terminate) Sends a connection release frame with a delimiter added.

A fiber channel terminal 1 as shown in FIG.
3 and a switch fabric 4 accommodating them, are connected to a connectionless network 6, and a connectionless network 6
Terminal 7 and fiber channel terminals 1 to 3
In order to perform communication with the connection, a connection conversion device 5 is required as shown in FIG. When performing connection-oriented communication, the connection conversion device 5 receives an IP packet from the terminal 7 and uses the connection to the partner terminal (for example, the terminal 2) if the connection is set on the switch fabric 4. To communicate. In addition, the connection conversion device 5
If the connection to the partner terminal is not set and the connection is not set to another Fiber Channel terminal, the connection is set and communication is performed by the above-described method.

[0006] The time required for this connection setting is about 30 microseconds. The transmission speed of the fiber channel is about 1 gigabit / second, and the loss due to connection setting overhead is 4 kilobytes / second, which is equivalent to two frames in terms of the maximum length (2 kilobytes) of the fiber channel frame. Current fiber channel systems are designed to activate connection-oriented communication when the length of a fiber channel frame exceeds a certain value. However, setting a class 1 connection for a transfer in which the length of the first frame exceeds a certain value and ends in a few frames is not advisable because the setting overhead increases. Therefore, it is desirable to set the connection only when the connection setting overhead becomes sufficiently small.

[0007]

As described above, in the communication system in which the fiber channel network and the connectionless network are connected, it is desirable to set the connection only when the overhead of the connection setting becomes sufficiently small. However, when the connection conversion device 5 receives a certain packet, it is difficult to determine whether a large number of packets are continuously transferred by only the processing of the IP layer. There is a need. Therefore, the following problems occur in the connection conversion device 5. (1) Since the protocol layer to be processed increases and the processing load increases, the processing capability of the connection conversion device 5 decreases. (2) In order to avoid a decrease in the processing capacity of the connection conversion device 5, a high-speed and expensive processor is required, which increases the cost. (3) Since the upper protocol layer may depend on the application on the fiber channel terminal side, the connection conversion device 5 may not be able to cope with it. The present invention has been made to solve the above problems,
Packet communication that performs connection-oriented communication for packet transfer with a long service time and connectionless communication for packet transfer with a short service time, even if the connection conversion device does not read the upper protocol. An object of the present invention is to provide a system connection method.

[0008]

According to the present invention, a plurality of packet communication terminals accommodated in a first network having both a connection-oriented communication function and a connectionless communication function are provided. And a connection conversion device for connecting the first network to a second network having a connectionless communication function, wherein the connection conversion device is transmitted from the second network. Among the packets, packets addressed to a packet communication terminal having a connection established with the own device are transferred by connection-oriented communication using the above connection, and packets addressed to a packet communication terminal not having the connection established. Are transferred by connectionless communication. Together, perform connection setting request from the own apparatus when communication with the packet communication terminal
Connection setup from the packet communication terminal
It is in response to a fixed request . Further, when the packet communication terminal communicates with the other terminal accommodated in the second network via the connection conversion device, the packet communication terminal may be a connectionless type communication at the beginning of the communication. For the packet transfer with a long service time, the connection converter is requested to set a connection. Further, as set forth in claim 3, the connection conversion device includes a connection-oriented communication buffer for storing a packet addressed to a packet communication terminal to which a connection has been established between itself and the connection conversion device. A connectionless communication buffer for storing a packet addressed to a packet communication terminal to which no connection is set, an address table for recording a port address of the packet communication terminal to which the connection is set, and the packet communication A control unit for recording a port address of the packet communication terminal in an address table when a connection setting is requested from the terminal; and a port address of a destination packet communication terminal among packets received from the second network. Is registered in the In the connection-oriented communication buffer, and when the port address of the destination packet communication terminal is not registered in the address table, a distribution unit for storing the received packet in the connectionless communication buffer. It is. Further, as set forth in claim 4, the first network is a fiber channel network, and the packet communication terminal requests connection setting using a fiber channel frame in which an SOFc1 delimiter is set. .

[0009]

Next, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram of a communication system showing an embodiment of the present invention, and FIG. 2 is a diagram showing a state of connectionless communication and connection-oriented communication in the communication system of FIG.
In the present embodiment, the first network having both the connection-oriented communication function and the connectionless communication function is a fiber channel network, and the switch fabric 4 is used as a switching device thereof.

A unique port address is assigned to each of the ports of the fiber channel terminals (packet communication terminals) 1, 2, and 3 accommodated in the switch fabric 4. These ports are connected to each port of the switch fabric 4 having the same port address.

In the present embodiment, an IP (Internet)
Protocol) The network using the protocol is connected to the second network, that is, the connectionless network 6.
And Terminal 7 is connectionless network 6
To be housed. The switch fabric 4 and the connection conversion device 5 are connected by ports having the same port address.

Next, the operation of such a communication system will be described with reference to FIGS. When the connection conversion device 5 receives an IP packet A1 addressed to the fiber channel terminal (hereinafter abbreviated as FC terminal) 2 from the terminal 7 in the connectionless network 6, the connection conversion device 5 converts the IP packet A1 into a plurality of fibers as shown in FIG. The frame is divided into channel frames (hereinafter, abbreviated as FC frames) B1 (divided into two in FIG. 2) and transmitted to the switch fabric 4.

The switch fabric 4 sends the FC frame B1 to the FC terminal 2 based on the destination port address in the frame header of the FC frame B1. At this time, if a connection destined for the FC terminal 2 is set on the switch fabric 4, the connection conversion device 5 transfers the FC frame to the FC terminal 2 by connection-oriented communication using the connection. Also,
When the connection to the FC terminal 2 is not set, the connection conversion device 5 transfers the FC frame to the FC terminal 2 by connectionless communication as shown in FIG.

The FC terminal 2 receives the FC frame B1 from the connection converter 5 in the form of connectionless communication,
It is determined whether the upper layer application (service) provided by the FC frame has a long transfer time. If the FC terminal 2 determines that the transfer time is long, that is, if the number of consecutive FC frames related to the upper layer application exceeds a predetermined number (for example, 10), the FC terminal 2 adds the SOFc1 delimiter to the FC frame (hereinafter, connection). C1) to the switch fabric 4, and requests the connection converter 5 to set up a connection.

When the connection conversion device 5 receives the connection setting request frame via the switch fabric 4, if no other connection via the switch fabric 4 has been set, the SOFn1 delimiter is used as a response signal to the connection setting request frame. To the switch fabric 4 (hereinafter, referred to as an ACK frame). The FC terminal 2 receives the ACK frame via the switch fabric 4. Thus, the connection between the FC terminal 2 and the connection conversion device 5 is set.

Until a connection is set, communication between the FC terminal 2 and the connection conversion device 5 is performed by connectionless communication (class 2 or class 3). For example, in FIG. 2, FC frames B1 and B2 corresponding to IP packets A1 and A2, respectively, and FC frames C1 and C2 from FC terminal 2 are transferred by connectionless communication.

The connection converter 5 transfers the IP packets A3 and A4 received after the transmission of the ACK frame to the FC terminal 2 by connection-oriented communication. Note that the ACK frame alone may be transmitted to the FC terminal 2, but in FIG. 2, the SOFn1 delimiter is set in the first frame of the two FC frames B3 divided and generated from the IP packet A3, and the ACK frame is set to this. As a role.

Similarly, the FC terminal 2 transfers the FC frame C3 transmitted after receiving the ACK frame to the connection conversion device 5 by connection-oriented communication. Release of the set connection is performed by FC
The terminal 2 transmits an FC frame to which the EOFdt delimiter is added (hereinafter, referred to as a connection release frame), or performs connection conversion when a non-communication state of the connection (a state in which packet transfer is not performed) exceeds a predetermined time. This is performed by transmitting a connection release frame from the device 5.

FIG. 3 is a block diagram showing a configuration example of the FC terminals 1, 2, and 3. Fabric interface 11
Are connected to the switch fabric 4. The fabric interface 11 stores the FC frame received from the switch fabric 4 in the connection-oriented communication buffer 12 when performing connection-oriented communication (class 1) with the connection conversion device 5. When connectionless communication (class 2 or class 3) is being performed with the connection conversion device 5, the received FC frame is stored in the connectionless communication buffer 13.

The control unit 16 assembles an IP frame from the FC frame stored in the buffer 12 or 13 and transfers it to the main memory 15 via the bus 14. Subsequently, the control unit 16 reads an IP packet from the main memory 15 via the connectionless communication buffer 13 and determines whether or not the upper layer application (service) provided by the IP packet has a long transfer time. .

If the control unit 16 determines that the transfer time is long, that is, if the number of FC frames related to the upper layer application exceeds a predetermined number (for example, 10), the control unit 16 sends control information indicating a connection setting request. F to the communication partner terminal, that is, the connection conversion device 5 or the terminal 7
It is stored in the connectionless communication buffer 13 in association with the C frame. Whether the transfer of the FC frame is continued for a long time is determined by the type of the upper layer application. The type of this application is, for example, T
The determination is made based on the port number of the CP (Transmission Control Protocol).

Next, the fabric interface 11
Looks at the control information attached to the FC frame destined for the partner terminal stored in the buffer 13, and when the control information indicates a connection setting request, stores the FC frame addressed to the partner terminal stored in the buffer 13. And sets the SOFc1 delimiter to the switch fabric 4.

When receiving the ACK frame from the connection conversion device 5, the fabric interface 11
Transfers the received FC frame transferred to the connectionless communication buffer 13 to the connection-oriented communication buffer 12, and the control unit 16 sends the received FC frame from the main memory 15 to the destination terminal transferred to the buffer 13. The FC frame is transferred to the buffer 12. The fabric interface 11 transfers the FC frame addressed to the other terminal stored in the buffer 12 to the connection converter 5 by connection-oriented communication.

When releasing the set connection, the control unit 16 attaches control information indicating the release of the connection to the FC frame addressed to the partner terminal, and
To be stored. When control information indicating disconnection is added to the FC frame addressed to the partner terminal stored in the buffer 12, the fabric interface 11 sets an EOFdt delimiter in the FC frame and sends the EOFdt delimiter to the switch fabric 4. Thus, the connection is released.

FIG. 4 is a block diagram showing a configuration example of the connection conversion device 5. The fabric interface 51 is connected to the switch fabric 4, and the network interface 52 is connected to the connectionless network 6. If the FC frame received from the switch fabric 4 is a frame from an FC terminal for which a connection has been established with the connection conversion device 5, the fabric interface 51 converts the received FC frame into a connection-oriented communication buffer 53. If the frame is from an FC terminal for which the connection has not been set, the received FC frame is stored in the connectionless communication buffer 54.

The FC frames stored in the buffers 53 and 54 are supplied to a converter 56 via a distributor 55.
When detecting the SOFc1 delimiter from the FC frame received by the fabric interface 51, the detection unit 57 notifies the control unit 58 that the SOFc1 delimiter has been detected.

The control unit 58 that has received the notification sends the SOFc stored in the connectionless communication buffer 54
From the connection setting request frame in which 1 delimiter is set, the port address of the FC terminal that has requested the connection setting (that is, the transmission port address in the frame header of the connection setting request frame) is taken out.
It is determined whether a connection setting request has been received from the C terminal. Then, the control unit 58 notifies the distribution unit 55 of the extracted transmission port address.

The control unit 58 stores the response information indicating the response to the connection setting request in the connectionless communication buffer 54 in association with the FC frame addressed to the FC terminal requesting the connection setting. The fabric interface 51 uses the F
When the response information is added to the FC frame addressed to the C terminal, the SOFn1 delimiter is set in the FC frame and transmitted to the switch fabric 4.

The FC terminal 2 that has requested connection setting
Receives the ACK frame via the switch fabric 4. Thus, the connection between the FC terminal 2 and the connection conversion device 5 is set. Next, the distribution unit 55 registers the port address received from the control unit 58 in an address table (not shown) provided therein.

The conversion unit 56 assembles an IP frame from the received FC frame received via the distribution unit 55,
This is passed to the network interface 52. The network interface 52 sends the IP frame to the connectionless network 6.

The network interface 52
Receives the IP frame from the connectionless network 6 and passes it to the conversion unit 56. Conversion unit 56
Divides a received IP frame received from the network interface 52 into a plurality of FC frames, specifies a destination FC terminal based on a destination IP address in the received IP frame, and divides a port address of the FC terminal. Set as the destination port address of the generated FC frame. Then, the conversion unit 56 passes the FC frame to the distribution unit 55.

The distribution unit 55 searches the address table based on the destination port address of the transmission FC frame received from the conversion unit 56, and if the destination port address is registered in the address table, connects the transmission FC frame to the connection table. Oriented communication buffer 53
When the destination port address is not registered in the address table, the transmission FC frame is transferred to the connectionless communication buffer 54.

The fabric interface 51 sends out the FC frame stored in the connectionless communication buffer 54 to the switch fabric 4 by connectionless communication, and transmits the FC frame stored in the connection oriented communication buffer 53 to the switch fabric 4. It is transmitted by connection-oriented communication.

Further, the detecting unit 57 calculates EOFdt from the FC frame received by the fabric interface 51.
When the delimiter is detected, the control unit 58 is notified that the EOFdt delimiter has been detected.

Upon receiving this notification, the control unit 58 stores the connection-oriented communication buffer 53 and sets the EOFdt delimiter in the connection release frame. The outgoing port address in the frame header of the release frame is taken out, and it is determined from which FC terminal the connection release request has come. Then, the control unit 58 notifies the distribution unit 55 of the extracted transmission port address. The distribution unit 55 deletes the received port address from the address table. Thus, the connection is released.

When the non-communication state of the connection exceeds a predetermined time, the control unit 58 transmits control information indicating disconnection to the FC terminal addressed to the FC terminal for which connection is being set.
While being stored in the buffer 53 along with the frame,
The port address of the FC terminal is notified to the distribution unit 55 to be deleted from the address table. When the control information indicating the disconnection is added to the FC frame addressed to the FC terminal stored in the buffer 53, the fabric interface 51 sets an EOFdt delimiter in the FC frame and sends it to the switch fabric 4. Thus, the connection is released.

[0037]

According to the present invention, it is only necessary for the packet communication terminal to determine whether to use connectionless communication or connection-oriented communication. Even without the provision, connection-oriented communication can be performed for a packet transfer with a long service time and connectionless communication can be performed for a packet transfer with a short service time, and the overhead due to connection setting is sufficiently reduced. be able to. Further, since it is not necessary to process up to a high protocol layer in the connection conversion device, it is possible to avoid a decrease in the processing capability of the connection conversion device due to processing of a higher protocol layer, and use an expensive processor for the control unit of the connection conversion device Eliminates the need. In addition, since the packet communication terminal may include a function of determining whether to use connectionless communication or connection-oriented communication in accordance with the application, the connection converter 5 is conscious of an upper protocol layer or application. Eliminates the need.

[Brief description of the drawings]

FIG. 1 is a block diagram of a communication system according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a state of connectionless communication and connection-oriented communication in the communication system of FIG. 1;

FIG. 3 is a block diagram illustrating a configuration example of a fiber channel terminal in FIG. 1;

FIG. 4 is a block diagram illustrating a configuration example of a connection conversion device in FIG. 1;

FIG. 5 is a diagram showing a frame structure of a fiber channel.

FIG. 6 Class 1 in a Fiber Channel system
It is a figure for explaining the setting procedure of.

[Explanation of symbols]

1, 2, 3: Fiber channel terminal, 4: Switch fabric, 5: Connection conversion device, 6: Connectionless network, 7: Connectionless terminal, 11, 51 ...
Fabric interface, 12, 53: Connection-oriented communication buffer, 13, 54: Connectionless communication buffer, 14: Bus, 15: Main memory, 16, 58: Control unit, 52: Network interface, 55 ... Distributor, 56 ... Converter, 57 ...
Detection unit.

Claims (4)

(57) [Claims] 1. A plurality of packet communication terminals accommodated in a first network having both a connection-oriented communication function and a connectionless communication function, and a second packet communication terminal having a connectionless communication function with the first network. And a connection conversion device for connecting to the network of the packet communication system, wherein the connection conversion device, among the packets transmitted from the second network, a packet having a connection established between itself and its own device. Packets destined for a communication terminal are transferred by connection-oriented communication using the connection, and packets destined for a packet communication terminal for which the connection is not set are transferred by connectionless communication and communicated with the packet communication terminal. When communicating Placed colleagues without a connection setting request, co from the packet communication terminal
A connection method for a packet communication system, characterized by responding to a connection setting request . 2. The connection method for a packet communication system according to claim 1, wherein the packet communication terminal performs communication when communicating with a partner terminal accommodated in the second network via the connection conversion device. A connection method for a packet communication system, characterized in that connectionless communication is performed at the beginning, and connection setting is requested to the connection converter for packet transfer with a long service time. 3. The connection method for a packet communication system according to claim 2, wherein said connection conversion device is connection-oriented for storing a packet addressed to a packet communication terminal to which a connection has been established with its own device. Buffer for type communication, a buffer for connectionless communication for storing a packet addressed to a packet communication terminal for which the connection is not set, and a port for recording a port address of the packet communication terminal for which the connection is set. An address table; a control unit for recording a port address of the packet communication terminal in an address table when a connection setting is requested from the packet communication terminal; and a packet communication destination packet among packets received from the second network. If the port address of the terminal is If the packet is registered in the connection-oriented communication buffer, the received packet is stored in the connection-oriented communication buffer. If the port address of the destination packet communication terminal is not registered in the address table, the received packet is stored in the connectionless communication. A connection system for a packet communication system, comprising: 4. The connection method for a packet communication system according to claim 2, wherein said first network is a fiber channel network, and said packet communication terminal is connected using a fiber channel frame in which a SOFc1 delimiter is set. A connection method for a packet communication system, characterized by requesting a setting.