JPH07135501A - Distributed node packet system - Google Patents

Abstract

(57) [Abstract] [Purpose] To guarantee the bandwidth for communications that require bandwidth guarantee and to limit the fluctuation delay time within a certain upper limit for communications that need to guarantee fluctuation delay time. To provide a distributed node packet system capable of [Structure] Consecutive multiple (fixed number) packets on the transmission path are treated as a frame, and for the communication that requires bandwidth guarantee and fluctuation delay time guarantee, the communication node is set within the frame to satisfy these required quality. Packet is marked as a "reservation" packet to make a reservation packet, and communication is performed using these reservation packets to guarantee the requested bandwidth and fluctuation delay time. Also, regarding call processing, each communication node By enabling the individual call processing,
A distributed node packet system that enables economicization by eliminating the need to arrange call processing nodes that perform centralized call processing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a distributed node packet system suitable for sharing a transmission line among a plurality of communication nodes and performing multimedia communication such as voice and image, and particularly, it requires bandwidth guarantee. It is possible to guarantee the bandwidth for communication and limit the fluctuation delay time for the communication that needs to limit the fluctuation delay time, and perform call processing between communication nodes centrally. The present invention relates to a distributed node packet system in which communication nodes are distributed and call processing is performed without installing call processing nodes.

[0002]

2. Description of the Related Art L sharing a transmission line with a plurality of communication nodes
AN technology is a collision detection type carrier sense multiple access (CSMA / CD) method, that is, data is transmitted after confirming that the transmission path is not in use.
When it collides with the data sent by another communication node, it detects it and resends it, or the token method, that is,
A method is known in which only a communication node that has received a token representing a transmission right on the network can transmit data, and when the transmission is completed, the token is passed to the next communication node.
These conventional LAN protocols are designed for the purpose of fairing the opportunity for one communication node to send bursty data to a transmission line. On the other hand, since media such as voice and images are vulnerable to data loss, when performing voice or image communication, it is necessary to strictly guarantee the band without being affected by other communication. That is, a communication protocol for multimedia including data, voice and images requires a function of guaranteeing a band.
However, in the conventional LAN protocol, FDDI
Other than (Fiber Distributed Date Interface) -II, there is no one having a function of guaranteeing a band. The FDDI-II described above also has a function of supporting bandwidth-guaranteed communication, but this is divided into a bandwidth-guaranteed communication bandwidth and a non-bandwidth-guaranteed communication bandwidth, and a transmission path is hybridized. Since the structure is used, the band is wasted due to the division loss.

Regarding the fluctuation delay time, it is necessary to limit the fluctuation delay time within a certain fixed value in order to prevent the receiving buffer from overflowing the receiving communication node. The conventional LAN protocol has no function of limiting the fluctuation delay time. Further, in the ATM communication system, the transmission line band secured by the relay system of the public network depends on the band required for communication and cell fluctuation (fluctuation delay time). The transmission path band that must be secured by the relay system can be made smaller as the required band is smaller and the fluctuation delay time is smaller. In the ATM communication method, a communication node uses a UPC for requesting bandwidth, fluctuation delay time, etc. for a network when a call is made.
(Usage parameter control) Declares the parameters and the network
At the point (reference point of the user / network interface), the communication node observes whether this value is being transmitted or not. Therefore, in the ATM communication protocol, for example, in the GFC (general flow control) protocol that controls the cell transmission amount between a plurality of user communication nodes, it is necessary to limit the fluctuation delay time to the declared value or less. . In addition, regarding these, for example,
You can refer to the description in "Technical Description" (Kyoritsu Shuppan 1993).

However, the GFC protocol proposal currently considered in ITU-TS (formerly CCITT) and the like does not have a function of limiting the fluctuation delay time to a certain value or less. For example, currently ITU-TS S
The 1992 recommendation for standardization of B-ISDN UNI, which is being advanced around G13, includes only the minimum necessary functions that B-ISDN service can provide, and ATM
Regarding the realization of a multi-access configuration that accommodates a plurality of user communication nodes in one UNI, which is one of the biggest problems of the cell layer, only the 4-bit control area is secured at the beginning of the ATM cell header and the fluctuation delay time is increased. The specific realization method such as the guarantee method is completely unspecified. Further, conventionally, in order to perform extension communication in the user premises network also in call processing, as shown in FIG. 17, a configuration example of the user premises network when a call processing node is installed is shown in FIG.
X (call processing node) was required. For this reason, when a company or the like tries to build a private network, there is a problem that (1) the entire user private network cannot be economically realized (2) the initial investment amount is large. Further, in the home network of N-ISDN, it is possible to have a multi-point type network configuration in which a plurality of communication nodes are connected by a bus, but there is a problem that extension communication cannot be performed between the communication nodes. In the home network of B-ISDN, it is desired to realize an extension communication function and a LAN function without disposing an expensive device such as a PBX.

[0005]

In the communication protocol shown in each of the above prior arts in which the transmission path is shared by a plurality of communication nodes, the band guarantee type communication and the non-bandwidth guarantee type communication are mixed. However, there is a problem in that a mechanism for guaranteeing the fluctuation delay time is not provided. Further, regarding the call processing method, there is a problem in that the method of performing the extension call processing by installing the PBX in the user premises network, which is shown in each of the above prior arts, cannot be economically achieved. The present invention has been made in view of the above circumstances, and a first object of the present invention is to solve the above-described problems in the prior art, to guarantee a band for communication that requires a band guarantee, and to reduce fluctuation delay time. It is an object of the present invention to provide a distributed node packet system capable of limiting the fluctuation delay time within a certain upper limit value for the communication that needs to guarantee the. A second object of the present invention is to perform exclusive control of call processing, call processing, bandwidth management, etc. by distributing communication nodes without installing call processing nodes, thereby constructing an economical user premises network. It is to provide a distributed node packet system that is suitable for the above.

[0006]

The above object of the present invention is to provide a distributed node packet system in which a plurality of communication nodes are connected by a transmission link and packet communication is performed between arbitrary communication nodes by using intra-frame packets on a transmission path. In the above, the plurality of communication nodes circulates the exclusive control token for preventing simultaneous call processing, each of the communication nodes captures the token at the time of calling, regardless of each call or call, It is determined whether or not the packet for the bandwidth request of the communication node can be secured in the frame, and if it can be secured,
A distributed node packet system characterized by setting a reserved display in a packet reserved area of a packet for a requested bandwidth, releasing the token, and capturing a packet at a reserved position for packet communication, or the plurality of distributed node packet systems. The communication node circulates the exclusive control token for preventing simultaneous call processing, each communication node captures the token at the time of calling, and the band of the communication node is collected for each call or regardless of the call. It is judged whether or not the requested packet can be secured within the frame within the range where the permissible fluctuation delay time can be guaranteed, and if so, the bandwidth for which the permissible delay time is guaranteed is reserved in the packet reservation area Distributed node packet characterized by setting display, releasing the token, capturing a packet at a reserved position and performing packet communication It is achieved by the stem.

[0007]

In the distributed node packet system according to the present invention, a plurality of (fixed number) continuous packets on the transmission path are treated as a frame, and for communication requiring bandwidth guarantee and fluctuation delay time guarantee, these requirements are required. The communication node adds a "reservation" mark to the packets in the frame so as to satisfy the quality to make reservation packets, and by using these reservation packets for communication, the required bandwidth and fluctuation delay time are guaranteed. Also, regarding call processing, each communication node can perform call processing individually, so that it is not necessary to arrange call processing nodes that perform call processing in a centralized manner, so that economic efficiency can be achieved. It was done. In addition, B
-In the ISDN subscriber premises network, extension communication can be performed only by the communication node function without installing an expensive call processing node.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. In the embodiments described below, a communication method that satisfies the above-mentioned quality requirements of the GFC protocol is shown. First, the required quality of the GFC protocol and the classification based on it will be described. The requirements for the communication quality of the GFC protocol are mainly the following two. (1) Bandwidth (2) Fluctuation delay time Details will be described below individually. (1) Bandwidth Communication quality depends on the media handled by the GFC protocol.
It can be divided into the following two. (a) Media for which strict bandwidth guarantee is required (voice / image) Bandwidth is set so that cell discard quality is about 10 ^-9 or less for images and 10 ^-3 to 10 ^-5 or less for voice. Need to guarantee. (b) Media (data) that does not require strict bandwidth guarantee

(2) Fluctuation delay time In the ATM communication system, a communication node declares UPC parameters such as a requested bandwidth and fluctuation delay time to the network when a call is made, and the communication node at the point T determines the value. Observe whether or not data is being sent in compliance. Therefore, the GFC protocol needs a function of limiting the fluctuation delay time to the declared value or less. Therefore, regarding the fluctuation delay time, the communication quality is divided into the following two. (a) Communication for which fluctuation delay time needs to be guaranteed (external line) (b) Communication for which fluctuation delay time does not need to be guaranteed (extension line) Due to the above, the traffic handled by the GFC protocol requires the required bandwidth and fluctuation delay time. It is classified into the following four types, depending on the conditions. (Type 1 communication) Band guarantee is required and fluctuation delay time guarantee is not required (Type 2 communication) Band guarantee is required and fluctuation delay time guarantee is required (Type 3 communication) Band guarantee is not required, and , Fluctuation delay time guarantee required (type 4 communication) Bandwidth guarantee not required, and fluctuation delay time guarantee not required

Next, a method of performing the above four types of communication will be described. FIG. 3 is a diagram showing the configuration of a distributed node packet system according to an embodiment of the present invention. In FIG.
21-23, 25, 27 are communication nodes (B-TE *), 2
Reference numerals 4 and 28 denote network terminators (B-NT1). Also, SS
B, SB, and TB indicate reference points of the interface. In the dual bus configuration shown in FIG. 3A, a communication node and a network terminating device are connected by an upstream dual bus and a downstream dual bus, and packets are sent to each bus. On the other hand, FIG. 3B shows a dual ring configuration, in which communication nodes are connected in a ring shape. in this case,
The packet is sent out on the ring. The present invention can be applied to other physical configurations. The format of a packet transferred between communication nodes is shown in FIG. The packet shown in this embodiment is roughly divided into a user information area and a control information area, and the control information area includes a destination address area and a reservation status setting area 29. The reservation status setting area 29 is a characteristic area of this embodiment.

FIG. 5 shows a frame format on the transmission path. The frame of this embodiment has 150 cells / frame.
(In the case of the ATM communication system, the cell length is fixed). Further, the cells forming the frame are composed of an ATM cell payload storing communication information and a GFC area for setting the reservation status of the cell. The example shown in FIG. 5 shows the reservation status in which all cells are unreserved cells. Hereinafter, various communications in this embodiment will be described. (1) When performing type 1 communication In this case, the communication node captures the token for call processing exclusive control, observes the reservation status of the cell on the frame, and obtains the cell position information of the "unreserved cell". From the reservation status of the cell on this frame and the requested bandwidth of the own communication node, it is determined whether or not this call can be accepted. If the number of cells corresponding to the required bandwidth can be secured, that is, if there are unreserved cells corresponding to the required bandwidth on the frame, change the GFC area of the cell used in this call to "reserved" and change the token. Release,
Communication is performed using the cell at that position.

Further, in the above description, an example of using the GFC area in the case of the ATM communication system is shown, but generally, for requesting bandwidth declaration, cell position designation, etc., the packet format shown in FIG. 4 is used. Needless to say, it may be performed and displayed according to a predetermined information setting method. Further, the "reservation" display method may be similarly displayed by a predetermined method. (2) When performing the second type of communication In this case, the communication node captures the token for exclusive control of call processing, observes the reservation status of the cell on the frame, and obtains the cell position information of the "unreserved cell". From the reservation status of the cell on this frame, the requested bandwidth of the own communication node and the fluctuation delay time, it is determined whether or not this call can be accepted. If the number of cells equivalent to the required bandwidth can be secured so that the fluctuation delay time can be guaranteed, that is, if there are unreserved cells corresponding to the required bandwidth that can guarantee the fluctuation delay time on the frame, call this The GFC area of the cell to be used is changed to "reserved", the token is released, and the cell at that position is used for communication.

Next, the operation of the above embodiment will be specifically described. 1 and 2 are diagrams showing a call admission control method in the case of performing the second type of communication. FIG. 1A shows a state of a frame before the communication node declares the requested bandwidth and the fluctuation delay time. In this example, cell 4,
7, 8, and 10 are reserved for the above-described first type communication and second type communication, and the cell 150 is reserved for the third type communication. In addition, cells 2, 3, 5, 6, 9, 11, ...
.., 149 are unreserved cells. Each number indicates a cell position from the beginning of the frame. Here, it is assumed that the communication node (# 1) makes a declaration as shown in FIG. 1B, that is, a fluctuation delay time of 2 cells and a required bandwidth of 50 M (bps). In this embodiment, the transmission line band is 1
The required bandwidth is 50 M (bps) and it is assumed that one frame is composed of 150 cells.
M (bps) means that cells can be reserved in the frame at equal intervals of 3 cells unless another communication node reserves the cells in the frame.

However, as in this example, when another node has already reserved a cell, the cell positions cannot be reserved at the same intervals of three cells as described above. As shown in FIG. 2 (c), the communication node secures a cell corresponding to the required bandwidth that can guarantee the fluctuation delay time from the unreserved cells. That is, from the fluctuation delay and the required bandwidth, the maximum inter-cell spacing is 5 cells (3 cells + 2 cells) to a minimum 1 cell (3 cells-2
The unreserved cells in the range of (cell) are reserved as required bandwidths that satisfy the fluctuation delay time. The state of the frame after reservation is as shown in FIG. That is, cell 2,
, 149 are reserved and used by the communication node as shown in FIG. 2 (e). In the case of the first type of communication, the operation is the operation excluding the cell selection satisfying the fluctuation delay from FIGS. 1 and 2. (3) When third-type communication is performed This communication is used when so-called connectionless communication is performed. In this case, the communication node has already subscribed to the connectionless (CL) data service,
Between the communication node and the connectionless server (CLS),
ATM layer connection is established.

In this communication, the maximum bandwidth and fluctuation delay time are declared by the user when the service is subscribed,
The call processing node is reserved by displaying the cell used for this communication in the GFC area as "CL reservation".
A communication node that uses the CL data service transmits using this reserved cell. Of course, this
"CL reservation" is displayed by writing a predetermined code in the GFC area. Next, the above operation will be specifically described. Fig. 6 shows call acceptance control in the case of performing the third type communication. The cell used for the third type communication shown in Fig. 6 (a) is reserved in advance so as to guarantee the total bandwidth and fluctuation delay declared by the service declaration from the subscriber. It should be noted that the CL reservation display method may be any method as long as it is a predetermined method, as shown in FIGS. 6 (b), 6 (c) and 6 (d).
The communication nodes # 2 to # 4, which perform the kind of communication, determine from the GFC area that the cell is the communication cell of the third kind, and capture the empty cell and perform transmission.

(4) When performing communication other than the above-mentioned first to third types In this case, non-reserved cells other than the cells reserved for the first to third types of communication are captured. Send. Figure 7
It is a figure which shows the call acceptance control method at the time of performing a 4th type communication. As shown in FIG. 7A, if there is an unreserved cell that is not reserved for first-type to third-type communication,
As shown in (b), (c), and (d), the communication nodes # 5 to # 74 that perform the fourth type communication capture and transmit the unreserved cells. 8 to 15 are diagrams showing an example of a call processing sequence in each of the above-described embodiments, and FIGS. 8 to 12 are diagrams for explaining a call processing signal sequence in the case of performing external line communication, and FIGS. FIG. 15 is a diagram illustrating a call processing signal sequence when performing extension communication. 8 and 9 and 13 are diagrams showing an example of the call processing signal sequence in the case of a completed call, and FIGS. 10 and 14 are examples of the call processing signal sequence in the case where the calling party runs out of bandwidth. Figure, Figure 1
1, FIG. 12 is a diagram showing an example of a call processing signal sequence when the receiving side does not respond due to lack of bandwidth on the receiving side,
FIG. 15 is a diagram showing an example of a call processing signal sequence when the called side does not respond.

For comparison, FIG. 16 shows Q.931 (CCIT
(T standard) shows a call processing signal sequence for external line communication / completed call. The difference between FIGS. 8 to 15 and FIG. 16 is that
In the distributed node packet system according to the present invention,
In order to perform the call acceptance determination, the processing for capturing and releasing the token for exclusive use in call processing and the determination processing in the communication node are added. Hereinafter, first, the operation shown in FIGS. 8 and 9 will be described for each sequence. First, when a calling request is made to the calling communication node, the calling communication node captures the token (step 1, hereinafter, this is referred to as "S1"), observes the reservation status of the cell on the frame, It is determined whether or not the cell position can be reserved, that is, whether or not there is a vacant band on the transmission path (S2). If the reservation is possible, the cell position is reserved (S3) and the call is made (SETUP).
(S4). At the destination communication node, when the call request arrives (S
5), the token is captured (S6), and it is determined whether or not the cell position can be reserved, that is, whether or not there is a free band on the transmission path (S7). If the reservation is possible, the cell position is reserved (S8) and the CALL PROC is returned (S9).

S10 is the aforementioned Q.931 (CCITT standard).
Is the same as the sequence. When the communication is completed, the token is captured (S11) and the reserved cell position is released (S11).
12), DISC is transmitted (S13). Upon receiving the DISC (S14), the opposite communication node captures the token (S15) and releases the reserved cell position (S1).
6). S17 is the same as the sequence of Q.931 described above. 10 to 15, only the reservation determination result of the cell position in the sequence is different, and each signal message and the content of the determination process are the same as those in FIGS. 8 and 9. That is,
FIG. 10 shows that the reservation of the cell position is not performed because the reservation is impossible due to the lack of bandwidth on the calling side.
1, FIG. 12 shows that the reservation of the cell position is not performed because the reservation cannot be made on the receiving side due to the shortage of the band. 13 to 15 show examples of call processing signal sequences in the case of a complete call, in the case of a shortage of bandwidth at the calling side and at the time of not answering at the called side in the case of extension communication, respectively. There is. According to the present embodiment, for a communication for which it is necessary to guarantee the bandwidth, when a call is made, a cell corresponding to the bandwidth to be used is reserved, and the communication node uses the cell at the reserved position so that the requested bandwidth is It is possible to guarantee 100%. Here, the number of discarded cells due to collision is zero.

Further, with respect to communication for which it is necessary to guarantee the fluctuation delay time, the cell to be used is reserved (designated) so that it is within the allowable fluctuation delay time at the time of calling. , A cell that violates the UPC can be set to 0. In addition, for a communication (third type communication) that uses a certain band that is a plurality of CL communication and that the fluctuation delay time must be protected, a cell used in a plurality of CL communication is assigned, It is shared by multiple CL communications. As a result, CL with a large ratio between the average rate and the peak rate
A statistical multiplex effect can be obtained for communication. Furthermore, for communication that does not require guarantee of bandwidth or fluctuation delay time (4th type communication), the remaining bandwidth is temporarily occupied by using cells that are not reserved by other communication. Can be sent. It is needless to say that the above embodiment shows one example of the present invention, and the present invention should not be limited to this.

[0020]

As described above in detail, according to the present invention, the bandwidth is guaranteed for the communication requiring the bandwidth guarantee, and the fluctuation delay is required for the communication requiring the fluctuation delay time. This has a remarkable effect of realizing a distributed node packet system in which the time can be limited within a certain upper limit value. Further, a distributed node packet system suitable for constructing an economical user premises network by performing exclusive control of call processing, call processing, bandwidth management, etc. by distributing communication nodes without installing call processing nodes. This is a remarkable effect that can be realized. More specifically, according to the present invention, both communication requiring bandwidth guarantee such as voice and image, and bandwidth non-guaranteed communication requiring effective use of bandwidth due to multiplexing effect of data, It can be handled by a single protocol. In addition, it is possible to simultaneously handle communication with a limited fluctuation delay time. Furthermore, it is possible to handle data communication with a high burst property at the same time. As a result, the present invention can be applied as the GFC protocol of the ATM communication system, including the case where the fluctuation delay time condition at the point T is particularly severe.

[Brief description of drawings]

FIG. 1 is a part of a diagram showing a call acceptance control system of a second type of communication according to an embodiment of the present invention.

FIG. 2 is another part of the diagram showing the call acceptance control system of the second type of communication according to the embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a distributed node packet system according to an embodiment.

FIG. 4 is a diagram showing a format of a packet transferred between communication nodes in the distributed node packet system according to the embodiment.

FIG. 5 is a diagram showing a frame format transferred between communication nodes in the distributed node packet system according to the embodiment.

FIG. 6 is a diagram showing a call acceptance control system of a third type of communication according to the embodiment.

FIG. 7 is a diagram showing a call acceptance control system of a fourth type of communication according to an embodiment.

FIG. 8 is a diagram (No. 1) for explaining a call processing signal sequence of a completed call when the outside line communication is performed in the embodiment.

FIG. 9 is a diagram (No. 2) for explaining the call processing signal sequence of the completed call when performing the outside line communication in the embodiment.

FIG. 10 is a diagram for explaining a call processing signal sequence when the calling side runs out of bandwidth in the case of performing external line communication in the embodiment.

FIG. 11 is a diagram (No. 1) explaining the call processing signal sequence when the called side does not respond when performing the outside line communication in the embodiment.

FIG. 12 is a diagram (No. 2) explaining the call processing signal sequence when the called side does not respond when performing the outside line communication in the embodiment.

FIG. 13 is a diagram illustrating a call processing signal sequence of a completed call when performing extension communication in the embodiment.

FIG. 14 is a diagram illustrating a call processing signal sequence when the calling side runs out of bandwidth in the case of performing extension communication according to the embodiment.

FIG. 15 is a diagram illustrating a call processing signal sequence when the called side does not respond when performing extension communication in the embodiment.

FIG. 16 is a diagram showing a call processing signal sequence of Q.931 (CCITT standard) external line communication / completed call.

FIG. 17 is a diagram showing a configuration example of a user premises network when a call processing node is installed.

[Explanation of symbols]

 21-23 Communication Node 24 Network Terminator 25-27 Communication Node 28 Network Terminator 29 Reservation Status Setting Area in Packet Control Information Area 30-32 Communication Node 33 Call Processing Node 34 Network Terminator 35-37 Communication Node 38 Call processing node 39 Network terminating device

Claims (2)

[Claims] 1. A distributed node packet system in which a plurality of communication nodes are connected by a transmission link and packet communication is performed between arbitrary communication nodes by using intra-frame packets on a transmission path, wherein the plurality of communication nodes simultaneously perform call processing. The token for exclusive control is circulated to prevent the communication from being performed, each communication node captures the token at the time of calling, and the packet for the bandwidth request of the communication node is framed for each call or regardless of the call. It is determined whether or not it can be secured inside, and if it can be secured, a reservation display is set in the packet reserved area of the packet for the requested bandwidth, and the token is released,
A distributed node packet system characterized by capturing a packet at a reserved position and performing packet communication. 2. A distributed node packet system in which a plurality of communication nodes are connected by a transmission link and packet communication is performed between arbitrary communication nodes by using intra-frame packets on a transmission path, wherein the plurality of communication nodes simultaneously perform call processing. The communication control node circulates the token for exclusive control so that each communication node captures the token at the time of calling, and allows the packet for the bandwidth request of the communication node for each call or regardless of the call. It is determined whether or not the fluctuation delay time can be ensured within the frame within a guaranteed range, and if the fluctuation delay time can be ensured, a reservation display is set in the packet reservation area of the packet of the bandwidth request bandwidth for which the allowable delay time is guaranteed, A distributed node packet system characterized by releasing tokens and capturing packets at reserved positions for packet communication.