JP3145971B2 - Frame relay network transfer system and frame relay exchange - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a frame relay communication system, and more particularly to a frame relay communication system which employs a datagram system as an intra-network transfer system to enhance the transfer capability in a frame relay network. The present invention relates to a preferred frame relay intra-network transfer method and a frame relay exchange.

[0002]

2. Description of the Related Art Conventionally, in frame relay communication, when a datagram, which is a connectionless communication form in which a call setup is not required, is adopted in an intra-network communication system, as shown in FIG. Without depending on
In order to guarantee the order of the VC (Permanent Virtual Circuit) communication in the network, sequence numbers (1 to 4) are assigned to the frames between the calling station 7 and the receiving station 8, and the destination is a frame relay exchange. The station 10 performs order control (such as control of expected sequence numbers). In the receiving station 9, the frames can be received in the order of the frames received from the users at the calling station 9 which is a frame relay exchange, and the order of the frames between the end and end users is guaranteed.

[0003]

SUMMARY OF THE INVENTION By the way, the frame
The relay communication is a protocol for transmitting data of an upper layer protocol transparently. In the frame relay communication, the transmission quality is assumed to be high and a protocol that may be encountered at the time of congestion / failure is considered. On the other hand, when congestion occurs in bursty traffic or a frame is dropped, if the order control procedure at the higher level is connection-type, the order control in the frame relay network is unnecessary. However, in the related art, since sequence control (management control of an expected sequence number, etc.) is always performed at the destination station 10, a useless function occurs in the frame relay network depending on a protocol of an upper layer of the frame relay. As a result, there is a problem that transfer efficiency is reduced.

The present invention has been made in view of the above circumstances, and has as its object to provide a frame relay network transfer system and a frame relay exchange which can enhance the transfer efficiency of communication within a frame relay network. I have.

[0005]

In order to solve the above-mentioned problems, according to the present invention, in a frame relay intra-network transfer method employing a datagram method as an intra-network transfer method, an upper layer The communication type of the protocol is set for each control information for identifying a call when subscribing to a frame relay network, and when transferring in a frame relay network, the communication type is determined, and the protocol of the upper layer is determined. It is characterized by performing frame transfer according to the communication type.

Further, according to the invention described in claim 2, according to claim 1,
In the above described intra-frame relay network transfer processing method, the communication type is one of a connectionless type requiring no call setup and a collection type requiring a call setup.

In order to solve the above-mentioned problems,
According to the third aspect of the present invention, a frame for receiving a frame from a subscriber terminal and transmitting the frame to a frame relay network side.
In a relay exchange, a frame receiving means for receiving a frame from a subscriber terminal, and a communication type of an upper layer protocol for each subscriber terminal, for identifying a call in the frame received by the frame receiving means. According to the control information, management control means for obtaining a corresponding communication type, and, if the communication type obtained by the management control means is connectionless type, order control means for giving a sequence number to the header of the frame, determines communication type obtained by the management control unit, said communication <br/> when signal type is a connectionless type, frame relay frames sequence number is provided by the sequence control means While transmitting to the network side, if the communication type acquired by the management control means is connection type , And wherein the frame received by the frame receiving means directly to and a network within routing control means for transmitting to the frame relay network side.

[0008] In order to solve the above-mentioned problem, claim 4
According to the present invention, in a frame relay exchange for receiving a frame from a frame relay network side and transmitting the frame to a subscriber terminal, an intra-network routing control means for receiving a frame from the frame relay network side; Management control means for managing a communication type of an upper-layer protocol for each of them, and acquiring a corresponding communication type according to control information for identifying a call in a frame received by the intra-network routing control means; Obtained by control means
The communication type is determined. If the communication type is a connectionless type, the sequence control unit that performs frame queuing control so that the frames are received in the order of the sequence numbers; and the communication type acquired by the management control unit is a connection type. In the case of the communication type, the frames received in the order of the sequence numbers are sequentially transmitted to the called subscriber terminal by the queuing control by the sequence control means, while the communication type acquired by the management control means is transmitted. Is a connection type, frame transmission means for directly transmitting the frame received by the intra-network routing control means to the destination subscriber terminal.

In the present invention, the communication type of the upper layer protocol is set for each DLCI of the subscriber, and the communication type is referred to at the time of transfer within the frame relay network, so that the communication type of the upper layer protocol is connection type. If there is, the order control is omitted, and the processing efficiency is allocated to another communication to increase the transfer efficiency.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

A. Configuration of Embodiment A-1. Network Configuration First, a network configuration according to an embodiment of the present invention will be described. FIG. 2 is a conceptual diagram illustrating a configuration of a network using frame relay communication according to an embodiment of the present invention. In FIG. 2, a PVC path is connected in advance to the calling terminal 7 and the called terminal 8, and the subscriber's PV is respectively connected.
DLCI (Data Link Connection Iden) for C path
tifier) is assigned. This DLCI value is control information for identifying a call, which is set in a header of a frame in frame relay communication, and is assigned when a subscriber contracts. The originating station 9, which is a frame relay exchange, compares the DLCI of the destination terminal 8 with the DLCI of the destination terminal 7.
Information 12a, PVC path information 13a, and a PVC management table 11a for managing the communication type 14a of the protocol of the upper layer, and the destination 10 similarly has a PVC management table 11b.

A-2. Configuration of Frame Relay Switch Next, the above-described frame relay switch (source station 9 and destination station 10) will be described. Here, FIG. 1 is a block diagram showing the configuration of the frame relay exchange of the present embodiment. In the figure, a frame relay exchange (originating station 9 and destination station 10) 6 includes a frame relay DL core control means 1,
It comprises a PVC management control means 2, an in-network frame header disassembly / assembly control means 3, an order control means 4, and an in-network routing control means 5.

The frame relay DL core control means 1 comprises:
Controls transmission and reception of frames between the user and the network. The PVC management control means 2 controls the remote DCI for each DLCI of the subscriber.
It manages LCI information and communication types of upper layer protocols. The in-network frame header disassembly / assembly control means 3 disassembles and assembles a header for transferring in the frame relay network. The sequence control means 4 manages the sequence control in the frame relay network. Network routing control means 5
Manages transmission / reception control of frames in the frame relay network.

The frame relay DL core control means 1 comprises:
When receiving the frame from the user side, it requests the PVC management control means 2 to obtain the remote destination information for the corresponding DLCI and the communication type of the upper layer protocol, obtains the destination information and the communication type, and It is assumed that the header disassembly / assembly control means 3 is requested to assemble the header in the network. If the communication type obtained from the PVC management control means 2 is connectionless type, after requesting the sequence control to add a frame sequence number, the network routing control means 5 is requested to transfer to the remote. . On the other hand, if it is a connection type, the request is made directly to the intra-network routing control means 5.

Upon receiving the frame from the inside of the network, the in-network routing control means 5 requests the PVC management control means 2 to call the communication type of the upper layer protocol for the corresponding DLCI, and disassembles and assembles the in-network header. The control unit 3 issues a request for disassembly of the header in the network. And P
If the communication type obtained from the VC management control means 2 is a connectionless type, after performing frame queuing control so as to be in the order of sequence numbers, a transmission request is made to the frame relay DL core control means 1. On the other hand, if the connection type is used, the request is sent directly to the frame relay DL core control means 1.

B. Next, the operation of the embodiment of the present invention will be described with reference to FIGS.
This will be described in detail with reference to FIG. In the following, the subscript a is attached to the component requirements of the originating station 9 and the subscript b is appended to the component components of the destination station 10. FIG. 3 is a flowchart showing the operation of the originating station 9 in the frame relay exchange. Upon receiving the frame 16 from the subscriber side, the frame relay DL core control means 1a extracts the DLCI value of the received frame 16 (steps A1 and A2), and sends the corresponding DLC to the PVC management control means 2a.
DLCI information 12a for I, PVC path information 13
a and a request to acquire information on the upper-layer protocol communication type 14a.

Upon receiving the request, the PVC management control means 2a performs a rationality check from the corresponding DLCI to see if it matches the DLCI information 12a (step A3), and if it matches, it becomes remote routing information. PV
The C path information 13a and the upper layer protocol communication type 14a are acquired (step A4), and a request for assembling the in-network header is sent to the in-network frame header disassembly / assembly control means 3a with the acquired information. On the other hand, if they do not match, it is determined that the frame is invalid, and the frame is discarded (step A).
5).

Upon receiving the request, the in-network frame header disassembly / assembly control means 3a performs assembling of the in-network header, and
The destination is set in the in-network header based on the C path information 13a (step A6), and it is determined whether the upper protocol communication type 14a is a connection type or a connectionless type (step A7). If the connection type is used, the transfer request to the remote side is sent to the in-network routing control means 5a. If it is a connectionless type, it requests the sequence control unit 4a to add a sequence to the header in the network.

In the order control means 4a, the requested DLC
A sequence number is assigned to the sequence in the network header in ascending order in I units (step A8), and a transfer request to the remote side is issued to the network routing control means 5a. Upon receiving the request, the intra-network routing control means 5a transfers the intra-network frame 17 to the remote side based on the destination information set in the intra-network header (step A9).

FIG. 4 is a flowchart showing the operation of the destination station 10 in the frame relay exchange.
The intra-network routing control means 5b receiving the intra-network frame 17 from the relay side extracts the PVC path information 13a of the received intra-network frame 17 (steps A10 and A1).
1), DLCI information 1 to PVC management control means 2b
A request is made to acquire information on the communication protocol 2b and the upper protocol communication type 14b.

In the requested PVC management control means 2b,
After acquiring the DLCI information 12b and the upper protocol communication type 14b of the transmission subscriber from the PVC path information 13a extracted from the header in the network (step A12), the upper protocol communication type 14b is connection type or connectionless type. Is determined (step A1).
3). If the connection type is used, a request for disassembly of the in-network header is made to the in-network frame header disassembly / assembly control means 3b with the acquired information. On the other hand, if it is a connectionless type, it requests the order control means 4b to guarantee the frame order with the acquired information.

Upon receiving the request, the sequence control means 4b acquires the sequence number of the received in-network header (step A).
14), the sequence number is compared with the expected sequence number managed by itself (step A15). If they match, a request for disassembly of the in-network header is issued to the in-network frame header disassembly / assembly control means 3b. On the other hand, if they do not match, it waits for a certain period of time until the expected sequence number is received (step A16).

Upon receiving the request, the in-network frame header disassembly / assembly control means 3b decomposes the in-network header (step A17) and sets the inherited DLCI information 12b in the DL core of the frame (step A18). . Then, a transfer request to the subscriber is made to the frame relay DL core control means 1b (step A19). The requested frame relay DL core control means 1b transmits the frame 16 to the subscriber.

C. Specific Example (Connection Type) Next, a specific example (connection type) of the embodiment of the present invention will be described in detail with reference to FIG. FIG. 5 is a block diagram showing a more specific network configuration. 1 or 2 are denoted by the same reference numerals (the suffix a is attached to the source station 9 and the suffix b is attached to the destination station 10), and the description is omitted. In FIG. 5, the DL of the calling terminal 7 is shown.
CI = 78 indicates that the PV is between DLCI = 584 of the destination terminal 8.
C is connected. Based on the DLCI = 78 of the frame 16 received from the calling terminal 7, the calling station 9
DLCI-P for searching the VC management table 11a
A VC management number correspondence table 15a is provided.
In the PVC management number correspondence table 15a, the PVC management number = 1
0 is set. In the PVC management table 11a indexed by the PVC management number = 10, as the DLCI information 12a, the DLCI of the accommodating subscriber = 78, the PV
As the C path information 13a, the partner PVC connection station number = 3,
The partner PVC management number = 58 is set.

Similarly, the destination station 10 also has a DLCI-PVC management number correspondence table 15b for retrieving the corresponding DLCI PVC management table 11b of the destination terminal 8, and the DLCI-PVC management number correspondence table 15b is included in the DLCI-PVC management number correspondence table 15b. Is P
VC management number = 58 is set. In the PVC management table 11b indexed by the PVC management number = 58, the DLCI of the accommodating subscriber is stored as DLCI information 12b.
CI = 584, the partner PV as the PVC path information 13b
C connection station number = 2 and partner PVC management number = 58 are set.

D. Operation of Specific Example Next, the operation of this specific example will be described in detail with reference to FIG. First, the frame relay DL core control means 1a receiving the frame 16 of DLCI = 78 from the calling terminal 7
Then, DLCI = 78 is taken out and a request is made to the PVC management control means 2a. In the requested PVC management control means 2a, the DLCI-PVC management number correspondence table 15a
, And retrieves the PVC management table 11a with the obtained PVC management number 10 from the
Acquires information of the partner station number = 3, the partner PVC management number = 58, and the upper protocol communication type = 1 (= connection type) that match CI = 78, and attaches the information to control disassembly / assembly control of the frame header in the network. A request for assembling the header is sent to the means 3a. Upon receiving the request, the in-network frame header disassembly / assembly control means 3a places a sequence on the frame 16
Assembles and sets the in-network header consisting of the VC management number and the partner station number, and performs upper-layer protocol communication type 14a.
(= 1: connection type), a transfer request to the remote side is issued to the in-network routing control means 5a. Upon receiving the request, the intra-network routing control means 5a transfers the intra-network frame 17 to the destination station 10 in accordance with the partner station number = 3 set in the intra-network header.

The in-network routing control means 5b, which has received the in-network frame 17 from the relay side,
7 and retrieves the other party's PVC management number = 58 and makes a request to the PVC management control means 2b. Requested PVC
The management control unit 2b searches the PVC management table 11b with the partner PVC management number = 58, and DLCI = 584,
The information of the upper layer protocol communication type 14b (= 1: connection type) is acquired, and a request for header disassembly is sent to the in-network frame header disassembly / assembly control unit 3b based on the communication type = 1. In-network frame header disassembly / assembly control means 3
b, the inherited DLCI = 584 is converted to the DL of the frame.
Frame relay DL core control means 1 set in core section
b. The requested frame relay DL core control means 1b transmits the frame 16 to the subscriber.

[0028]

As described above, according to the present invention, according to the present invention, in the contract when the user subscribes, the protocol communication type (connection type protocol / connectionless type protocol) of the upper layer of frame relay is set for each PVC. By negotiating and referring to the communication type during transfer within the frame relay network, if the connection-type protocol is used, the order control function that overlaps with the upper-layer protocol is not performed. It is possible to increase the transfer efficiency of communication within the frame relay network.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a frame relay exchange according to an embodiment of the present invention.

FIG. 2 is a conceptual diagram illustrating a configuration of a network according to the present embodiment.

FIG. 3 is a flowchart illustrating an operation on the transmitting side according to the present embodiment.

FIG. 4 is a flowchart showing an operation on the destination side according to the present embodiment.

FIG. 5 is a conceptual diagram showing a configuration of a network for explaining the present invention more specifically.

FIG. 6 is a conceptual diagram for explaining an intra-network transfer method in a conventional frame relay network.

[Explanation of symbols]

1 frame relay DL core control means (frame reception means, frame transmission means) 2 PVC management control means (management control means) 3 frame header disassembly / assembly control means in network 4 order control means 5 routing control means in network 6 frames Relay exchange 7 Calling terminal (subscriber terminal) 8 Called terminal (subscriber terminal) 9 Calling station (frame / relay switch) 10 Called station (frame / relay switch) 11a, 11b PVC management table 12a, 12b DLCI information 13a, 13b PVC path information 14a, 14b Upper protocol communication type 15a, 15b DLCI-PVC management number correspondence table 16 Frame 17 Network frame

Claims (4)

(57) [Claims] 1. A control method for identifying a call at the time of subscribing to a frame relay network in a frame relay network intra-network transfer system employing a datagram system as a communication method of an upper layer protocol. This information is set for each information, and when transferring in the frame relay network, the communication type is set.
Determining a different, frame relay network in the transfer processing method which is characterized in that a frame transfer in accordance with the communication type of the upper layer protocol. 2. The intra-frame relay network transfer processing method according to claim 1, wherein the communication type is one of a connectionless type requiring no call setting and a connection type requiring a call setting. 3. A frame relay exchange for receiving a frame from a subscriber terminal and transmitting the frame to a frame relay network side, a frame receiving means for receiving a frame from the subscriber terminal, and an upper layer for each subscriber terminal. Management control means for managing the communication type of the protocol, and according to the control information for identifying the call in the frame received by the frame receiving means, obtaining a corresponding communication type; and determine the type of communication
However , if the communication type is a connectionless type, an order control unit that assigns a sequence number to the header of the frame, and if the information type obtained by the management control unit is a connectionless type, The frame to which the sequence number is assigned by the
While transmitting to the relay network side, if the communication type obtained by the management control means is connection type, the network received by the frame receiving means is directly transmitted to the frame relay network side. A frame relay switch comprising routing control means. 4. A frame relay exchange for receiving a frame from a frame relay network and transmitting the frame to a subscriber terminal, an intra-network routing control means for receiving a frame from the frame relay network, and a subscriber terminal. Management control means for managing a communication type of a protocol of an upper layer for each, and acquiring a corresponding communication type according to control information for identifying a call in a frame received by the intra-network routing control means; Judgment of communication type acquired by control means
If the communication type is connectionless, the sequence control means for performing frame queuing control so that the frames are received in the order of the sequence numbers; and the communication type acquired by the management control means is connectionless. In this case, by the queuing control by the sequence control means, the frames received in the order of the sequence numbers are sequentially transmitted to the destination subscriber terminal, while the communication type acquired by the management control means is connection type. And a frame transmitting means for directly transmitting a frame received by the intra-network routing control means to a called subscriber terminal.