JPH10322349A - Atm communication equipment and atm communication system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To describe much control information and to precisely control them in an ATM cell unit by inserting a control cell where control information obtained from the routing table of packets/frames in a payload into the prescribed position of the ATM cell constituting packet/frame and transmitting it. SOLUTION: A packet/frame recognition part 112 refers to the routing table 115 of packet/frame based on header information which is read from the ATM cell 11 constituting packet/frame. An additional information bestowal mechanism part 113 gives new distribution priority and bypass route information, which are thus obtained, to the header part of the ATM cell 11. A control cell insertion part 114 inserts the control cell 12 where control information obtained in the routing table 115 in the payload into the head of the ATM cell 11 so as to transmit it. A control cell extraction part 151 outputs the ATM cell 11 constituting packet/frame in accordance with the description of the extracted control cell 12. Thus, precise control is realized.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ATM communication device used in an ATM transmission network, wherein an ATM communication device for converting a packet or a frame used in computer communication into an ATM cell and a plurality of the ATM communication devices are connected. ATM communication system configured.

[0002]

2. Description of the Related Art In ordinary computer communication, signals from a computer are transmitted in units called IP packets or MAC frames. This packet or frame is converted into an ATM cell when it is transmitted to the ATM transmission network. In ATM, signals of voice, data, video, etc. are transmitted by ATM.
AAL (ATM A) which standardizes information to be added in order to absorb the difference of each quality condition when dividing into cells
daptation Layer). This AAL has 5
There are types, but AAL5 is a protocol that assumes computer communication for main uses.

FIG. 8 shows an example in which a packet or frame is transferred to an ATM.
An example of mapping in the case of celling is shown. AAL5 is a cell division / assembly sublayer (S
AR) and a convergence sub-layer (CS) which is a function for each user data unit.

[0004] Information (packets or frames) from the upper layer is added with a CS header and a CS trailer in the CS of AAL5, and is divided into 48-byte units in the SAR.
Furthermore, a 5-byte header is added by the ATM layer to
A byte ATM cell is formed. Thus, AAL
In 5, the flag indicating the end of the packet or frame is A
Although defined in the TM cell header, other bits for writing the in-network control information are not defined.

[0005]

In transmitting packets or frames, control information used in the network must be transmitted by some method in order to perform detailed control in packet or frame units. In order to transmit such control information, in a method of setting a VP (virtual path) / VC (virtual channel) different from a main signal to another communication device, it is necessary to secure VP / VC for control. Therefore, the same number of control VPs / VCs as VPs / VCs transmitting the main signal is required. In other words, VP / VC for main signal transmission that can be handled by one device is reduced by half. Further, since the main signal cell and the control cell are transmitted by different VP / VCs, the respective received delay fluctuations are different. In order to control the packet or frame by absorbing the delay fluctuation, it is necessary to temporarily store the data in a buffer or the like and then process the packet or frame, which causes a transmission delay.

In a method using a control signal line other than an ATM cell, a network different from a main signal is transmitted. Also in this case, it is necessary to absorb different delay fluctuations in each network, and it is necessary to temporarily store the data in a buffer or the like and process the same as in the method of setting the control VP / VC, thereby causing transmission delay. . An object of the present invention is to provide an ATM communication apparatus and an ATM communication system that can easily transmit control information used for control in units of packets or frames in a network and on the same path as a main signal.

[0007]

An ATM communication apparatus according to the present invention transmits control information necessary for performing control on a packet or frame basis at the time of transmitting an ATM cell constituting a packet or a frame to a user cell. Same VPI /
This is described in the payload of the control cell to which the VCI has been added.
This control cell is composed of A
It is inserted at the head of the TM cell or at a predetermined position.

Thus, it is not necessary to change the configuration of a packet or a frame, and control information can be easily added in the ATM layer, and a large amount of control information can be described in a control cell. Become. Furthermore, since the same route as the main signal can be used,
The order control and the delay fluctuation absorbing mechanism become unnecessary. Also, AT
Since control information of a packet or a frame higher than the M layer is transmitted in the control cell, reassembly of the packet or the frame becomes unnecessary, and the control time can be reduced.

[0009] OAM defined by standardization
The (Operation, Administration and Maintenance) cell is for notifying information related to maintenance operation such as device alarm and error detection. However, the defined O
AM cells are at the VP / VC level, and are not added in units of packets or frames.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment of ATM Communication Device) FIG. 1 shows a first embodiment of the ATM communication device of the present invention. Here, a case where a control cell is used in the device will be described. Also, a case where a control cell is inserted before a packet / frame will be described, by recognizing a packet / frame at an input interface and examining a routing table.

In the figure, the input interface (# 1,
# 2) 110 and 120 are ATM cell processing units 111 and 1
21, packet / frame recognition units 112 and 122,
It has additional information providing units 113 and 123, control cell insertion units 114 and 124, and packet / frame routing tables 115 and 125. The switch unit 140 is an AT
An M cell routing table 141 is provided. The output interfaces (# 1, # 2) 150 and 160 include control cell removing units 151 and 161 and ATM cell processing units 152 and 162, respectively.
And

The input interface 110 receives a packet /
Upon receiving the ATM cell 11 constituting the frame, the AT
The packet / frame recognition unit 112 reads the header information of the packet / frame via the M cell processing unit 111. Next, referring to the packet / frame routing table 115 based on the header information, routing information, delivery priority, bypass route information, and the like are checked. The additional information adding mechanism unit 113 adds the new delivery priority / detour route information obtained by the check to the header of the ATM cell 11 constituting the packet / frame. Next, the control cell insertion unit 11
4 inserts a control cell 12 in which detailed control information on a packet / frame obtained by examining the packet / frame routing table 115 is described in a payload. The control cell 12 and the ATM constituting the packet / frame
The cells are sent from the input interface 110 to the switch unit 140 in the order of the cells 11.

In the input interface 120, similarly, A which constitutes the input packet / frame
The switching unit 140 processes the TM cell 11, and in the order of the control cell 12, and the ATM cell 11 constituting the packet / frame.
To send to. The switch unit 140 inputs ATM cells from the input interfaces 110 and 120 and outputs the output interface (イ ン タ フ ェ ー ス) according to the ATM cell routing table 141.
1, ♯2) Switching to 150,160.

In the output interfaces 150 and 160,
The control cells are identified and extracted by the control cell extracting units 151 and 161. Here, the control cell is distinguished from other cells by one of the following methods. A first method utilizes a tag used in a switch. Tag is input interface 1
When the control cells are inserted by the control cell insertion units 114 and 124 of the control units 10 and 120, the control cells are transferred to the switch unit 140 and switched. In the second method, a bit of PT1 used for identifying an OAM cell is provided to the control cell 12. Third
Is determined from the position where the control cell 11 is inserted. For example, if a control cell is inserted at the beginning as in this embodiment,
The tail cell can be identified by looking at the bit of PT3, and the ATM cell coming next to the same VPI / VCI can be recognized as the head control cell 12.

The packet / frame is controlled according to the description of the payload of the control cell 12 extracted by any of the above methods. AT that constitutes this packet / frame
The M cell 11 is transmitted to the ATM cell processing units 152 and 162 at the AT.
Output interfaces 150 and 160 after M processing
Output from

(Second Embodiment of ATM Communication Device) FIG.
Shows a second embodiment of the ATM communication device of the present invention.
Here, a case where a control cell is used between devices will be described. Also, the input interface recognizes the packet / frame and checks the routing table.
The case where the frame is inserted before the frame will be described.

In the figure, an input interface (# 1)
110 and the output interface (# 2) 160 are connected to the subscriber side and are the same as those of the first embodiment shown in FIG. On the other hand, the input interface (# 2) 120 and the output interface (# 1) 150 are connected to the relay side, and the control cell insertion unit 1 according to the first embodiment shown in FIG.
24 and the control cell removal unit 151 are removed.

Control cell 1 from output interface 150
2 and an ATM cell 11 forming a packet / frame are output, and a control cell 12 and an ATM cell 11 forming a packet / frame are input from the relay side to an input interface 120.
Is input to Note that the ATM communication device of the present embodiment is:
Input interface 120 and output interface 1
A control cell is transmitted / received between a plurality of communication devices having the same function via 50.

(Third Embodiment of ATM Communication Device) FIG.
Shows a third embodiment of the ATM communication device of the present invention.
In this embodiment, the control cell insertion unit 114 of the input interface (# 1) 110 in the second embodiment is moved to the output interface (# 1) 150, and the control cell removal unit 161 of the output interface (# 2) 160 is input. Interface (# 2) 120. It should be noted that the ATM communication device of the present embodiment has the input interface 120
The control cell is transmitted / received between a plurality of communication devices having the same function via the output interface 150.

(Fourth Embodiment of ATM Communication Device) FIG.
Shows a fourth embodiment of the ATM cell of the present invention. In the present embodiment, the packet / frame routing tables 115 and 125 in the second embodiment are provided with detour path information, and the additional information adding units 113 and 123 use the header information of the ATM cell based on the detour path information. VPI for bypassing
/ VCI to which a routing control function for changing is added.

In each of the above embodiments, the information contained in the header of the ATM cell constituting the packet / frame includes VPI (virtual path identifier) / VC
I (virtual channel identifier) / CLP (cell loss priority indication). However, if the information is not originally described in the header of the ATM cell, or if the number of bits in the header is insufficient, the information described in the payload of the control cell according to the present invention is used. Also, when the number of bits of the tag in the device is insufficient, the information described in the payload of the control cell is used.

The control information includes, for example, an input / output interface number of a partner apparatus and a port number of a switch, and when the apparatus is closed, the monitoring control unit of the apparatus controls. In the case of the detour control, information is given from a control part that manages the entire network, such as an operation system (OpS) or a route server, by sequentially describing the routes that are taken. Regarding the delivery priority, since only two states of 0/1 can be expressed by the CLP bit, it is used when it is desired to further define the packet / frame transfer service. For example, priorities are determined at the time of contract with the user, and when a packet / frame is applicable from VPI / VCI / IP, etc., each device determines and inserts / removes cells to perform priority control.

[0023]

【Example】

FIG. 5 shows a first embodiment (ATM communication system) using an ATM communication device according to the present invention. In this embodiment, the ATM communication device 100,
It is assumed that a VP is set between 200 and control cells are transmitted and received between devices. ATM that constitutes packet / frame
The case where the cell 11 is input to the input interface 110 of the ATM communication device 100 and output from the output interface 270 of the ATM communication device 200 will be described.

The input interface 110 of the ATM communication device 100 corresponds to the input interface 110 of the second embodiment shown in FIG. 2, and the input interface 220 of the ATM communication device 200 corresponds to the third interface shown in FIG. Those corresponding to the input interface 120 of the embodiment but not directly related to the description of the operation are omitted. When the ATM cell 11 constituting the packet / frame arrives at the input interface 110 of the ATM communication device 100, the packet / frame recognition unit 112 detects the head cell of the packet / frame. In this embodiment, the intended output interface is the output interface 27 of the ATM communication device 200.
Since it is 0, the fact is described in the payload of the control cell 12. Further, the same VPI / VCI as that of the ATM cell 11 forming the packet / frame is assigned to the control cell 12. The control cell insertion unit 114 inserts and outputs the control cell 12 before the head cell of the ATM cell 11 constituting the packet / frame. The insertion position of the control cell 12 is not limited to the head, and may be inserted at a predetermined midway position.

The ATM cells 11 and control cells 12 constituting the packet / frame output from the input interface 110 are sent to the cross-connect device 400 via the switch section 140 and the output interface 160. In the cross-connect device 400, the control cell 12,
Information (VPI / V) described in the header of the ATM cell in the same manner as normal ATM cell processing, without distinguishing the ATM cell (user cell) 11 constituting the packet / frame.
CI), the data is output via the input interface 410, the switch unit 420, and the output interface 430.

In the ATM communication device 200, the control cell 12 arriving at the control cell removing unit 261 of the input interface 220 is extracted, and the ATM cell constituting the packet / frame that subsequently arrives is extracted according to the control information read from the payload. 11 is performed. It should be noted that the same VPI / VC
I and I confirm the same packet / frame from the source. In the present embodiment, the control cell 12 is provided with an ATM cell 11 constituting a packet / frame,
70, and the ATM cell 11 is connected to the output interface 270 according to the description. Thus, the packet / frame can be reassembled and transferred to the target output port without reading the header.

(Second embodiment: case where control cells are transmitted and received between input / output interfaces in the device) FIG. 6 shows a second embodiment using the ATM communication device of the present invention. In the present embodiment, in the ATM communication apparatus, A which constitutes a packet / frame input to the input interface 110
A TM cell 11-1 and an ATM cell 11- constituting a packet / frame input to the input interface 120
2 is the same output interface 150, the input interface 11
It is assumed that control cells 12-1 and 12-2 are transmitted and received between 0 and 120 and the output interface 150.

The ATM communication apparatus of this embodiment corresponds to the first embodiment shown in FIG. 1, but those which are not directly involved in the description of the operation are omitted. ATM cells 11-1 and 11-2 constituting a packet / frame are almost simultaneously AT
When the data arrives at the M communication device and the respective output destinations are the same output interface 150, the transfer is simply performed in the ATM layer. Cannot be identified as the source. Therefore, the control cells 12-1 and 12-2 are inserted by the control cell insertion units 114 and 124 of the input interfaces 110 and 120, respectively. On the other hand, ATM cells 11-
1, 11-2 are assigned different VPI / VCI, and each VP
The I / VCI is described in the corresponding control cells 12-1 and 12-2.

In the output interface 150, the VPI / VC described in the control cells 12-1 and 12-2 inserted in the unit of the ATM cell constituting the packet / frame.
I, and reads the corresponding ATM cell 11-1,
11-2 is output in packet / frame units. Thereby, even if a plurality of ATM cells having the same destination arrive and are sent to the same output interface 150 through the switch unit 140, it is possible to distinguish each of the sources.

FIG. 7 shows a third embodiment (ATM communication system) using an ATM communication device according to the present invention. In this embodiment, the input interface 11 of the ATM communication apparatus 100 is used.
0 to the output interface 25 of the ATM communication device 200
When the ATM cell 11 that constitutes the packet / frame is transmitted to 0, a bypass route via the ATM communication device 300 is used due to traffic congestion or failure. If such a bypass route is not set in advance, it is necessary to notify the ATM communication device 300 that the ATM cell 11 is to be transferred to the ATM communication device 200. This bypass route information is described in the payload of the control cell 12, and inserted and transmitted before the head cell of the ATM cell 11 constituting the packet / frame.

The ATM communication apparatus of the present embodiment corresponds to the fourth embodiment shown in FIG. 4, but those which are not directly involved in the description of the operation are omitted. Further, the additional information providing mechanism unit 113 and the packet / frame routing table 115
Together with the path control unit 116. When the ATM cell 11 constituting the packet / frame arrives at the input interface 110 of the ATM communication device 100, the packet / frame recognition unit 112 and the route control unit 116
Detour route information via the TM communication device 300 (new VP
I / VCI). Then, the bypass route information is described in the payload of the control cell 12, and the same VPI / VCI as that of the ATM cell 11 forming the packet / frame is added. The control cell insertion unit 114 inserts and outputs the control cell 12 before the head cell of the ATM cell 11 constituting the packet / frame.

The ATM cells 11 and control cells 12 constituting the packet / frame output from the input interface 110 are transmitted to the ATM communication device 300 via the switch 140 and the output interface 150. In the ATM communication device 300, the transfer route is determined by the packet / frame recognition unit 312 and the route control unit 316, and A is determined according to the bypass route information (VPI / VCI).
Transfer to the TM communication device 200.

In the ATM communication device 200, the transfer path is determined by the packet / frame recognition unit 312 and the route control unit 316, and the control cell 12 and the packet / frame A constituting the packet / frame transferred from the ATM communication device 300 are transferred.
The TM cell 11 is processed. Further, the control cells 12 are extracted by the control cell extracting unit 251 of the output interface 250, and the ATM cells 11 constituting the packet / frame are controlled according to the control information read from the payload.

In each of the embodiments described above, the number of control cells to be inserted is not limited to one, but may be a plurality of control cells. Further, the insertion position of the control cell is not limited to the head of the ATM cell constituting the packet / frame, and may be inserted at a predetermined midway position. Further, the control cell may be attached not only to the head of the ATM cell constituting the packet / frame but also to the end of the ATM cell constituting the packet / frame.

[0035]

As described above, the ATM communication apparatus and the ATM communication system of the present invention provide control information insertion / insertion.
Since extraction is performed in ATM cell units, control information can be easily inserted / extracted. Further, since a large amount of control information can be described, fine control can be performed for each ATM cell constituting a packet / frame.

In the cross-connect device in the middle of the route, only the processing of the ATM layer is required, and the processing at the packet / frame level is not required. Can be transmitted.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a first embodiment of an ATM communication device of the present invention.

FIG. 2 is a block diagram showing a second embodiment of the ATM communication device of the present invention.

FIG. 3 is a block diagram showing a third embodiment of the ATM communication device of the present invention.

FIG. 4 is a block diagram showing a fourth embodiment of the ATM communication device of the present invention.

FIG. 5 is a block diagram showing a first embodiment using the ATM communication device of the present invention.

FIG. 6 is a block diagram showing a second embodiment using the ATM communication device of the present invention.

FIG. 7 is a block diagram showing a third embodiment using the ATM communication device of the present invention.

FIG. 8 is a diagram showing an example of mapping when a packet or a frame is converted into an ATM cell.

[Explanation of symbols]

11 ATM cells constituting packets / frames 12 Control cells 100, 200, 300 ATM communication devices 110, 120, 130, 210, 220, 230, 3
10,320 Input interface 111,121 ATM cell processing unit 112,122,212,222,312 packet /
Frame Recognition Units 113, 123 Additional Information Addition Mechanism Unit 114, 124 Control Cell Insertion Unit 115, 125 Packet / Frame Routing Table 116, 216, 316 Route Control Unit 140, 240, 340 Switch Unit 141 ATM Cell Routing Table 150, 160, 170, 250, 260, 270, 3
50,360 Output interface 151,161,251,261 Control cell removal unit 152,162 ATM cell processing unit 400 Cross-connect device 410 Input interface 420 Switch unit 430 Output interface

Claims (5)

[Claims] A plurality of input interfaces; a plurality of output interfaces; and a switch unit for switching an ATM cell from the input interface to the output interface. The input interface includes an ATM cell processing unit, A packet / frame recognizing unit for reading header information of an ATM cell constituting a frame; a packet / frame routing table including packet / frame unit control information; and an ATM constituting a packet / frame based on control information obtained from the routing table. An ATM communication device comprising: an additional information adding mechanism for adding a header to a cell; a control cell in which control information obtained from a routing table of the packet / frame is described in a payload in the input interface; Be composed A control cell insertion unit for inserting the ATM cell into a predetermined position of the ATM cell to be inserted, extracting and extracting the control cell from the output interface, and controlling the ATM cell constituting the packet / frame according to the control information described in the payload thereof. An ATM communication device, comprising: a control cell removing unit for performing the above operation. 2. A plurality of input interfaces connected to the subscriber side and the relay side, a plurality of output interfaces connected to the subscriber side and the relay side, and switching of ATM cells from the input interface to the output interface. An ATM cell processing unit, a packet / frame recognizing unit that reads header information of ATM cells constituting the packet / frame, and a packet / packet containing control information in packet / frame units. An ATM communication device comprising: a frame routing table; and an additional information adding mechanism for adding control information obtained from the routing table to a header of an ATM cell constituting a packet / frame. The packet / frame routing must be A control cell insertion unit for inserting a control cell in which control information obtained from a packet table is described in a payload into a predetermined position of an ATM cell constituting the packet / frame, and an output interface connected to the subscriber side. , Identifying and extracting the control cell, and forming a packet / frame according to the control information described in the payload thereof.
An ATM communication device comprising a control cell removing unit for controlling a TM cell. 3. A plurality of input interfaces connected to the subscriber side and the relay side, a plurality of output interfaces connected to the subscriber side and the relay side, and switching of ATM cells from the input interface to the output interface. A packet / frame recognizing unit for reading header information of an ATM cell constituting the packet / frame, and a packet / frame including control information in a packet / frame unit An ATM communication device comprising: a routing table of (1), and an additional information adding mechanism for adding control information obtained from the routing table to a header of an ATM cell constituting a packet / frame. Control information that describes control information in the payload. A control cell insertion unit that inserts the control cell into a predetermined position of an ATM cell constituting the packet / frame. The control cell is identified and extracted from an input interface connected to the relay side, and is described in a payload thereof. AT configuring a packet / frame according to control information
An ATM communication device comprising a control cell removing unit for controlling an M cell. 4. The ATM according to claim 2 or claim 3.
An ATM communication apparatus according to the communication apparatus, wherein the control information in units of packets / frames includes input / output interface numbers, delivery priority information, or bypass route information. 5. The ATM communication device according to claim 2, wherein the control cells are connected to each other.
A characterized in that it is configured to be transmitted between communication devices.
TM communication system.