JPH0766836A - Idle band notice system in packet exchange network - Google Patents

Abstract

PURPOSE:To utilize a band effectively by setting the idle band to be reported to each terminal equipment under connection based on the product of a weight coefficient depending on number and a reserved band and the actually operating band of each terminal equipment, an idle band of the transmission line and its nondecreasing function. CONSTITUTION:A priority control means 13 of a packet exchange 8 provides an exchange output of a high priority packet HP of high/low priority packets(HP/LP) with priority and a band allocation means 10 allocates a guarantee band requested by a terminal equipment. Furthermore, idle band setting notice means 11, 12 set an idle band from which a terminal equipment makes transmission for an LP and the set and allocated bands are reported to each terminal equipment. Packet transmission reception means 19, 23 and an idle band notice processing means 22 of a communication control means 18 of each terminal equipment send HP, LP according to the notice from the means 12. The means 11 sets an idle band based on a product alpha(i)beta(Rl) Rl among an available band Rl being the difference C-Rh between a transmission line capacity C and the sum Rh of guarantee bands of each terminal equipment to be connected to the transmission line, a weight alpha(i) with respect to a terminal equipment (i) and a nondecreasing function beta(Rl) of the available band Rl. Thus, the band is effectively utilized.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a free band notification system in a packet switching network.

[0002]

2. Description of the Related Art Asynchronous transmission mode (ATM: Async)
In a packet-switched network in which a terminal reserves a used band with respect to the network prior to the transmission of the data, represented by a hornous Transfer Mode), when the traffic characteristics of the data actually transmitted by the terminal are known, By declaring an appropriate bandwidth to use, it becomes possible to effectively use network resources such as bandwidth while satisfying a predetermined communication quality.

A LAN (Local Area Network) distributed over a wide area by using such a packet switching network.
In the case of interconnecting orks), it is difficult to understand the traffic characteristics transmitted from the router of the LAN corresponding to the above-mentioned terminal, and the router declares an appropriate bandwidth to the packet network prior to data transmission. There is a problem that it is difficult. For this reason, it is effective for the router to perform bandwidth variable control in which the utilization bandwidth declared during data transmission is dynamically increased or decreased according to the amount of packets arriving.

When performing variable bandwidth control, there is a problem in the time required from the terminal issuing a bandwidth change request to the packet network until the request is accepted and the bandwidth can be changed. In particular, packet networks with extremely large transmission capacity
Since the number of packets arriving before the band is actually changed increases, the buffering delay at the terminal increases and the possibility of packet discard due to buffer overflow increases.

To address this issue, Bandwi
The method called dth Optimizer is IEEE
E INFOCOM '91, pp. 1145-1150
Has been proposed to. Bandwidth Advert
In the izing, the packet switch notifies the terminal currently connected to the unused band, so that the notified unused band can be used for data transmission in addition to the used band reserved by the terminal. It was done. At this time, when using the notified unused band, the communication quality of the packet transmitted in the reserved used band is guaranteed by transmitting the packet with low priority.

FIG. 4 is a conceptual diagram of an ATM switching network using a conventional free band notification system.

In FIG. 4, 1-1, 1-2, 1-3 are ATM exchanges, 2-1, 2-2, 2-3 are terminals, 3 is a data packet, 4 is a free band notification control packet, 5-
1 is a virtual channel used by the terminal 2-1; 5-2 is a virtual channel used by the terminal 2-2; 5-3 is the terminal 2-1;
Virtual channels used by other than 2-2, 6-1, 6-2,
6-3 are ATM exchanges 1-1, 1-2, 1-, respectively.
Value of free band notified from 3 to terminal 2-1; 7-1, 7
Reference numerals -2, 7-3, 7-4 and 7-5 represent transmission lines.

The terminals 2-1 and 2-2 respectively transmit data to the terminal 2-3 using the virtual channels 5-1 and 5-2. In this example, the terminal 2-
The control packets for notifying the free band for 1 and 2-2 are also transmitted using the same virtual channel used for data transmission. Also, virtual channels 5-1 and 5-2
Share the transmission lines 7-3 and 7-4, and the transmission line 7-
Available bandwidths of 3 and 7-4 are 2 Mbps and 6 respectively
Assume that it is Mbps. At this time, in the conventional free band notification method, the transmission path 7- is sent to both terminals 2-1 and 2-2.
RL = 2 Mbp as free bands of 3 and 7-4, respectively
s, RL = 6 Mbps is notified as a free band.

[0009]

However, Ban
In the case of using the advertising method, the exchange notifies the unused bandwidth to all connected terminals sharing the transmission path, so that all terminals simultaneously transmit packets using the notified unused bandwidth. , There is a possibility that the quality of the reserved bandwidth cannot be guaranteed due to congestion of the network due to the inflow of a large amount of low-priority packets at one time. Even if the exchange guarantees the quality of the reserved bandwidth for the high-priority packets regardless of the inflow amount of the low-priority packets, the problem of inequalities between terminals regarding the utilization of the unused bandwidth is unavoidable.

In view of the above, the present invention provides a mechanism for notifying congestion in the network by providing a mechanism for notifying a value of a part of the unused band of the transmission line which can be used with a low priority in the packet switching network. It is an object of the present invention to provide means for suppressing the band and effectively using the band.

[0011]

A vacant band notifying system in a packet switching network according to claim 1 of the present invention is a packet switching device for switching and outputting packets, and a terminal equipped with communication control means for controlling transmission and reception of packets. In the packet switching network, the packet switch has priority control means for preferentially switching and outputting high-priority packets with respect to low-priority packets, bandwidth allocation means for allocating a guaranteed bandwidth required by a terminal, and transmission. For a packet terminal that shares a route, a free band setting means for setting a free band that the terminal can send as a low priority packet, and a free band set by the free band setting means by using a free band notification control packet. An idle band notifying means for notifying the terminal, and a communication control means for the terminal, and a packet receiving means for receiving a packet. Free bandwidth notification processing means for extracting the free bandwidth notification control packet from the packet receiving means and holding the free bandwidth, and sending the high priority packet below the guaranteed bandwidth allocated by each packet switch on the packet path, Packet transmission means for transmitting a low-priority packet at a value equal to or less than the minimum value of the free bandwidth notified from each switching equipment on the path, and the free bandwidth setting means in the packet switching equipment is connected to each connected terminal i. The available bandwidth RL represented by the difference (C−RH) between the free bandwidth to be notified and the sum RH of the guaranteed bandwidths of the connected terminals that share the transmission path C and the connected terminal i. A (i) and the non-decreasing function β related to the available bandwidth RL
(RL) (≧ 0) Value α (i) β (RL
) It is set to RL.

A free band notification method in a packet switching network according to a second aspect is the one according to the first claim, wherein the free band setting means is provided for each of the N terminals i (1≤i≤N) being connected. On the other hand, the weights α (i) are all set to the same value α.

A vacant band notifying system in a packet switching network according to a third aspect is the vacant band notifying method according to the second aspect, wherein the vacant band setting means sets α = 1 / N.

The vacant band notifying system in the packet switching network according to claim 4 is the one according to any one of claims 1 to 3,
The terminal transmits a free band notification request packet to the packet switch, and the packet switch notifies the free band only to the terminal that has transmitted the received free band notification request packet by using the free band notification means. Is.

A vacant band notifying system in a packet switching network according to a fifth aspect is the one according to the fourth aspect, wherein the terminal is
A value of the required free bandwidth is written in the free bandwidth notification request packet, and the free bandwidth setting means sets the weight α (i) for the terminal i based on the required free bandwidth value written in the free bandwidth notification request packet. Is.

[0016]

[Operation] An empty band notification system in the packet switching network of the present invention will be described.

As described above, the exchange is provided with a means for notifying a part of all connected terminals sharing a transmission line or all the terminals as a free band of a part of the unused band of the transmission line.

Then, in the case of the method of claim 1, the value of the free band to be notified to each terminal is the number of terminals to be notified,
It is set by the product of the reserved band of each terminal or the weight determined by the band actually used in the reserved band, the non-decreasing function of the unused band of the transmission line, and the unused band of the transmission line. In the case of the method of claim 2, the empty band setting means sets the weights α (i) to the same value α for each of the N terminals i (1 ≦ i ≦ N) being connected. To do. In the case of the method of claim 3, the free band setting means sets α = 1 / N.

Further, in the case of the method of claim 4, as the timing of notifying the free band, the exchange notifies the free band at regular intervals, or sets the free band only to the terminal for which the free band notification request is made. Let me know. Claim 5
The method of claim 4, wherein the terminal writes the value of the requested free bandwidth in the free bandwidth notification request packet,
The free band setting means weights the terminal i based on the value of the requested free band written in the free band notification request packet.
Set (i).

At this time, by making it possible to declare the maximum free band used by the terminal together with the notification request, it is possible to construct a packet network that more reflects the user's request and can also effectively use the band.

This makes it possible to suppress the occurrence of congestion due to notifying all the terminals of the unused bandwidth of the transmission path. In addition, the value of the free bandwidth to be notified to each terminal is determined according to the reserved bandwidth of the terminal, the actual bandwidth usage of the terminal, the required free bandwidth of the terminal, and the unused bandwidth of the current transmission path. It becomes possible to set. As a result, it is possible to provide a traffic control mechanism having a higher degree of freedom and effective use of bandwidth.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

FIG. 1 is a conceptual diagram of an ATM switching network using the free band notification method in this embodiment.

In FIG. 1, 1-1, 1-2, 1-3 are ATM exchanges, 2-1, 2-2, 2-3 are terminals, 3 is a data packet, 4 is an empty band notification control packet, 5-
1 is a virtual channel used by the terminal 2-1; 5-2 is a virtual channel used by the terminal 2-2; 5-3 is the terminal 2-1;
Virtual channels used by other than 2-2, 6-1, 6-2,
6-3 are ATM exchanges 1-1, 1-2, 1-, respectively.
Value of free band notified from 3 to terminal 2-1; 7-1, 7
Reference numerals -2, 7-3, 7-4 and 7-5 represent transmission lines.

The terminals 2-1 and 2-2 respectively transmit data to the terminal 2-3 using the virtual channels 5-1 and 5-2. In this example, the terminal 2-
The control packets for notifying the free band for 1 and 2-2 are also transmitted using the same virtual channel used for data transmission. Also, virtual channels 5-1 and 5-2
Share the transmission lines 7-3 and 7-4, and the transmission line 7-
Available bandwidths of 3 and 7-4 are 2 Mbps and 6 respectively
Assume that it is Mbps. At this time, the free band setting means 1
When the second and sixth methods described later are used in No. 1, RL = 1 Mbp for both terminals 2-1 and 2-2.
s and RL = 3 Mbps are notified as free bands of the transmission lines 7-3 and 7-4, respectively.

FIG. 2 shows an example of the structure of a packet switch having free band notification means.

In FIG. 2, 8 is a packet switch, 9 is a switch, 10 is a bandwidth allocation means, 11 is a free bandwidth setting means, 12 is a free bandwidth notifying means, 13 is a priority control means, 14 is an input data line, and 15 is Output data line, 16-
Reference numeral 1 is a control packet input data line, 16-2 is a control packet output data line, and 17-1 and 17-2 are control lines.

Here, the switch 9 exchanges and outputs the packet. The band allocating means 10 allocates the guaranteed band requested by the terminal using the guaranteed band request control packet input from the control packet input data line 16-1. The free band setting means 11 inputs from the control line 17-1 the total RH of the bands allocated by the band allocating means 10 for each output line, and the transmission capacity C of the output line.
The value obtained by subtracting RH from (C-RH) is defined as the available bandwidth RL.

Now, seven methods for notifying a free band to the terminal i in communication will be described.

(1) First Method The value of the free band rL (i) set by the free band setting means 11 is the available band RL and the weight α for the terminal i.
(I) is multiplied by a non-decreasing function .beta. (RL) for RL to obtain a value .alpha. (I) .beta. (RL) RL. Note that the non-decreasing function β
(RL) means a function having a value obtained by differentiating it, that is, a slope of 0 or more, and includes, for example, a logarithmic function, a quadratic function, etc., which is arbitrarily set. The non-decreasing function β (RL) is multiplied by rL as RL increases.
This is to increase the capacity of (i) to prevent data congestion.

The free band notification means 12 generates a free band notification control packet, and writes the free band value rL (i) input using the control line 17-2 in the information field of the free band notification control packet. Then, the data is transmitted to the terminal i using the control packet output data line 17-2.

That is, the free bandwidth rL for the terminal i
The value of (i) is as follows.

[0033]

[Equation 1] (2) Second method The free band setting means 11 causes the N terminals i (1
For each of ≦ i ≦ N), set the weights α (i) to the same value α.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0035]

[Equation 2] (3) Third Method The free band setting means 11 sets α = 1 / N.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0037]

[Equation 3] However, N represents the number of terminals to be notified of the free band.

(4) Fourth Method The free band setting means 11 causes each of the N terminals i (1) being connected.
For each of ≦ i ≦ N), the value of the weight α (i) is set to the terminal i
The guaranteed bandwidth assigned to the terminal is set to a value obtained by dividing the guaranteed bandwidth assigned to the N terminals being connected.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0040]

[Equation 4] However, rH (i) represents the guaranteed band for the terminal i.

(5) Fifth Method The free band setting means 11 causes the N terminals i (1
≦ i ≦ N), the value of the weight α (i), the band that the terminal i is actually using in the guaranteed band, and the N terminals that are currently connected in the guaranteed band are actually Set to a value divided by the sum of the bandwidth used for.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0043]

[Equation 5] However, r′H (i) represents the band actually used by the terminal i among the guaranteed bands.

(6) Sixth Method The free band setting means 11 always sets the value of the non-decreasing function β (RL) for the free band RL to 1 regardless of the value of the free band RL.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0046]

[Equation 6] (7) Seventh Method The terminal i writes the value of the requested free band in the free band notification request packet, and the free band setting means 11 uses the value of the requested free band written in the free band notification request packet. Set weight α (i) for terminal i.

That is, the free band rL for the terminal i
The value of (i) is as follows.

[0048]

[Equation 7] However, r'L (i) represents a free band requested by the terminal i.

Further, there are the following three setting methods as the generation timing of the free band notification control packet generated by the free band notification means 12.

(A) A free band notification packet is generated at regular intervals.

(B) A free band notification packet is generated when the available band changes.

(C) In the seventh method, when a free band notification request is issued from a terminal, a free band notification packet is generated.

The above A to C are A and B, A and C and B.
And C, A and B and C, A and (7), B and (7), and A and B and (7) can be combined and applied.

FIG. 3 shows a block diagram of the communication control means of the terminal.

In FIG. 3, 18 is a communication control means, and 19
Is a packet transmitting means, 20 is a priority adding means, 21 is a packet transmission interval control means, 22 is a free band notification processing means, 23 is a packet receiving means, 24 is a data line, and 25 is a control line.

Here, the packet receiving means 23 performs the receiving process of the packet arriving from the network. At this time, if the received packet is a control packet for free band notification,
This is taken out and output to the free band notification processing means.

The free band notification processing means 22 extracts the value of the free band written in the free band notification control packet input from the packet receiving means 23, and the control line 2
5-1 and 5-2 are used to output to the priority addition means 20 and the packet transmission interval control means 21, respectively.

The priority adding means 20 adds priority to the input packet using the value of the free band input by the free band notification processing means 22, and outputs it to the packet transmission interval control means 21. At this time, first, if data can be transmitted in a band within the guaranteed band of the terminal, the packet is set to a high priority. For data that exceeds the guaranteed bandwidth of the terminal, a packet that can be transmitted in the band of the empty band is set to low priority and output to the packet transmission interval control means 21, and a packet that cannot be transmitted in the band of the empty band is discarded. To do.

The packet transmission interval control means 21 adjusts the packet transmission interval using the value of the free band input by the free band notification processing means 22. At this time, the reciprocal of the guaranteed bandwidth of the terminal is used as the transmission interval for the high-priority packet. On the other hand, for low-priority packets, the reciprocal of the available bandwidth is used as the transmission interval.

In the present embodiment, when the seventh method and the method (C) are used, a control packet for requesting a free bandwidth notification and a guaranteed bandwidth request used for requesting a guaranteed bandwidth are provided. The control packet is generated by a part other than the communication control means. These control packets can be transmitted even during data transmission. That is, it is possible to change the required free bandwidth during communication and the required guaranteed bandwidth.

[0061]

As described above, the conventional Bandwidth Adv is provided by the free band notification method in the packet switching network of the present invention.
Even if the traffic generated from the terminal, which is a feature of ertising, is uncertain, while maintaining the advantage of being able to effectively use the band, the Bandwidth Advertiser
It is possible to suppress the occurrence of congestion due to notifying all terminals of the unused bandwidth of the transmission path, which is a drawback of tiling. Furthermore, the value of the free band to be notified to each terminal, such as the reserved band amount for each terminal, the actual band usage amount for each terminal, the required free band amount for each terminal, and the unused band amount of the current transmission path, Since it is possible to set in consideration of various factors, it is possible to provide a traffic control mechanism which has a higher degree of freedom according to the usage pattern of the network and can effectively use the band.

[Brief description of drawings]

FIG. 1 is an AT using a free band notification method according to the present invention.
It is a conceptual diagram of an M switching network.

FIG. 2 is a configuration example of a packet switch having free band notification means according to the present invention.

FIG. 3 is a configuration diagram of communication control means of a terminal using the present invention.

FIG. 4 is a conceptual diagram of an ATM switching network using a conventional free band notification method.

[Explanation of symbols]

1-1, 1-2, 1-3 ATM Switch 2-1, 2-2, 2-3 Terminal 3 Data Packet 4 Free Band Notification Control Packet 5-1 Virtual Channel Used by Terminal 2-1 5-2 Virtual channel used by terminal 2-2 5-3 Virtual channel used by terminals other than terminals 2-1 and 2-6 6-1 Value of free band notified from ATM switch 1-1 to terminal 2-1 6-2 ATM Free band value notified from the exchange 1-2 to the terminal 2-2 6-3 Free band value notified from the ATM switch 1-3 to the terminal 2-3 8 Packet switch 9 Switch 10 Band allocating means 11 Free band setting means 12 Free Band Notification Means 13 Priority Control Means 14 Input Data Lines 15 Output Data Lines 16-1 Control Packet Input Data Lines 16-2 Control Packet Output Data Lines 17-1, 17-2 Control Lines 1 Communication control means 19 packet transmitting means 20 priority adding means 21 packet transmission interval control means 22 free band notification process unit 23 packet receiving means 24 the data line 25 control line

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location 9076-5K H04Q 11/04 R

Claims (5)

[Claims] 1. A packet switching network comprising a packet switching device for switching and outputting packets and a terminal equipped with communication control means for controlling packet transmission / reception, wherein the packet switching device converts high priority packets into low priority packets. Priority control means for preferentially exchanging output with respect to, the bandwidth allocating means for allocating the guaranteed bandwidth required by the terminal, and the vacant bandwidth that the terminal can send as a low priority packet to the packet terminals sharing the transmission path And a free band notifying unit for notifying the terminal of the free band set by the free band setting unit using a free band notification control packet, and the communication control unit of the terminal, The packet receiving means for receiving the packet and the free bandwidth notification control packet are extracted from the packet receiving means to determine the free bandwidth. The available free bandwidth notification processing means and the high-priority packet that is less than the guaranteed bandwidth allocated by each packet switch on the packet path are sent, and the free bandwidth less than or equal to the minimum value notified by each switch on the packet path is sent. Packet transmission means for transmitting low-priority packets, and the free bandwidth setting means in the packet switch shares the free bandwidth to be notified to each connected terminal i with the transmission path capacity C and the transmission path. Available bandwidth RL represented by the difference (C-RH) from the sum RH of guaranteed bandwidths of connected terminals
And the value α (i) β (RL) RL represented by the product of the weight α (i) for the terminal i in communication and the non-decreasing function β (RL) (≧ 0) for the available bandwidth RL. A free bandwidth notification method in a packet switching network characterized by: 2. The vacant band setting means sets weights α (i) to the same value α for each of the N terminals i (1 ≦ i ≦ N) being connected. Claim 1
Free bandwidth notification method in the described packet switching network. 3. A free band notification method in a packet switching network according to claim 2, wherein said free band setting means sets α = 1 / N. 4. The terminal sends a free band notification request packet to a packet switch, and the packet switch uses the free band notification means only for the terminal that sent the received free band notification request packet. 4. A free band notification method in a packet switching network according to claim 1, wherein a band is notified. 5. The terminal writes the value of the requested free band in the free band notification request packet, and the free band setting means sets the value for the requested free band for the terminal i based on the value of the requested free band written in the free band notification request packet. The free band notification method in a packet switching network according to claim 4, wherein a weight α (i) is set.