JPS6135646A - Line exchange switch with packet exchange function - Google Patents

Abstract

PURPOSE:To reduce the delay time in packet transmission by adding a packet exchange function to a time division spatial switch. CONSTITUTION:In case of packet exchange, to which incoming packet exchange a packet incoming from an input terminal 12 is transferred is decided, the packet is re-edited into an inter-network packet. When the inter-network packet is transmitted in a time division spatial switch SW3 and a packet display bit P is logical 1, the inter-network packet is extracted from an incoming highway 2 and received, and transmitted to packet buffers 331-33M according to a destination address D. A packet selector 35 extracts the inter-network packet and transmitted to an output highway 4. An incoming packet exchange 5 extracts the inter-network packet, reproduces it into the original packet and the result is outputted from a packet exchange output terminal 53.

Description

DETAILED DESCRIPTION OF THE INVENTION (Technical Field) The present invention relates to a circuit switching switch with a packet switching function.

(Prior Art) Conventionally, in a time-division switch network that is based on circuit switching and can also perform packet switching, a circuit-switched path is established between an input-side packet switching device and an output-side packet switching device. It is configured to perform packet communication through this path.

For this reason, a procedure and time are required to set up a path, and the path settings cannot be changed sufficiently in response to sudden changes in packet switching traffic, resulting in packets becoming jammed in the buffer memory along the way. This method has the drawback of increasing packet transmission delay time. In addition, by inserting a packet switching function in the middle of the path between the input side packet switching device and the output side packet switching device, it is possible to transfer packets without setting up a path. Since packet transfer is started after reception, the disadvantage is that the memory for storing packets increases and the packet transmission delay time also increases.

(Objective of the Invention) An object of the present invention is to install a means for dividing a packet and reassembling it into a fixed-length packet format having a short packet length as a packet within a switch network at a stage upstream of a time-division space switch within a switch network. , and by placing a circuit for exchanging packets within the switch network in the time-division space switch in parallel with a circuit for circuit switching, the above disadvantages are solved, and the circuit switching function remains the same as before, but packets can be exchanged with a short transmission delay time. It is an object of the present invention to provide a circuit switching switch with a packet switching function capable of performing switching.

(Structure of the Invention) According to the present invention, there is provided an intra-network packet creation circuit that divides a packet and reconfigures it into a short intra-network packet, and a changeover switch that selects either the intra-network packet or circuit switching data. , when the intra-network packet that has passed through the changeover switch passes through the time-division space switch, it branches before the time-division space switch, extracts and stores it, and stores it in an empty time slot on the outgoing highway of the time-division space switch. a time division space switch having means for inserting the accumulated intra-network packets into the network; and a packet reproducing circuit that receives and stores the intra-network packets on the outgoing highway and returns them to the original packets. A circuit switching switch with a packet switching function is obtained.

(Example) Next, the present invention will be explained with reference to the drawings.

FIG. 1 is a block diagram showing an embodiment of the circuit switching switch with packet switching function of the present invention, and FIGS. 2 and 3 are examples of the input highway/output highway signal format and the intra-network packet format in FIG. 1, respectively. FIG.

In FIG. 1, this embodiment shows the originating packet switching device (
a time-division space switch (hereinafter referred to as SW) 3 connected to the NA by an input highway 2;
(hereinafter referred to as NB) 5. NA1 is the line switching input terminal 11. Packet exchange input terminal 12. Intra-network packet creation circuit 13° connected to packet exchange input terminal 12 Circuit exchange input terminal 11 and intra-network packet creation circuit 13
The output of the changeover switch 4 is input to the input I
- Input to 8W3 via iway 2. Also, 8W
3 is a packet extraction circuit 31 connected to the input cable 2; A packet detection and analysis circuit 32 connected to the output of the packet extraction circuit 31. Packet buffers 331, 332, to 33 connected to the output of the packet detection and analysis circuit 32
M.

Input 301 connected to input highway 2 and each input 302 from other similarly 1-configured N-1 blocks.
~3ON and the eight inputs 301°302.7
- line selector 34 for selecting one of the soNs. Input 351 from bucket buffer 331 and each input 352 from other similarly configured N-1 blocks. ~35
N and the eight inputs 351, 352, ~35N
The output of either the line selector 34 or the packet selector 35 is input to the NB 5 via the output highway 4. Furthermore, NB5 is a packet reproducing circuit 51. connected to output highway 4. A line switching output terminal 52 connected to the output highway 4. It includes a packet exchange output terminal 53 connected to the output of the packet reproduction circuit 51.

Next, in FIG. 2, the signal format on the input highway and the output highway is 8-bit data PCM with a packet display bit P added to form one data with 9 bits. Also, in Figure 3, the network packet format starts with flag F, has the destination number and source number 0, then has data area DA and error check code E, and finally ends with flag F. do.

Next, the operation of this embodiment will be explained using FIGS. 1 to 3.

The operation etc. will be explained step by step.

In the case of normal line switching, input terminal 1 for line switching of NAL
The input signal inputted from 1 passes through the selector switch 14, goes directly to the input highway 2, and is connected to SW3.

The input signal from the input highway 2 passes through the line selector 34 and is output to the output/S9A4. The signal is input to the output aNB 5 and transmitted to the line switching output terminal 52. Therefore, the delay time is minimal and the operation is no different from that of a conventional time-division space switch.

Next, in the case of packet switching, the packet input from the packet switching input terminal 12 of NAL is sent to the network packet creation circuit 1.
In step 3, check the destination of the packet, decide which destination packet switching device to forward this packet to within the switch network,
The number of the destination packet switching device (for example, NB5) is used as the destination number, and the packet is reconfigured into an intra-network packet with the number of NAl as the source number 0. In other words, 7 in Figure 3
The entire packet between 272 and 272 is divided into small pieces, stored in the data area DA in the intra-network packet in order from the beginning of the packet, and sequentially sent out. When this intra-network packet is transmitted within 8W3, the packet indicator bit Pt in the input highway signal (shown in FIG. 2) is set to logic value 11''.

An intra-network packet sent to SW3 using a time slot that is not used for circuit switching in the input highway signal is input by the packet extraction circuit 31 when the packet display bit P is a logical value of "1". highway 2
and sent to the packet detection and analysis circuit 32. The packet detection and analysis circuit 32 examines the signal system taken out from the input highway 2, detects the flag F, and sends this intra-network packet with the destination number and source number 0 to one of the packet buffers 33M. When the packet selectors 3 and 5 find a time slot tf that is not used for circuit switching on the output highway 4, the packet selectors 3 and 5 select the bucket buffer 331 containing the intra-network packets for the output highway.
The intra-network packets are extracted from the network packet 1 and are continuously transmitted to the time slots which are not used for circuit switching on the output highway 4 until the intra-network packet 1 is completely transmitted. At this time, in the time slot used for the intra-network packet on the output highway 4, the packet indication bit P is set to the logical value "11". When one intra-network packet is sent out in this manner, a new intra-network packet It is taken out from the next bucket buffer 332 and placed on the output highway 4. When there is no intra-network packet to be sent to the bucket buffer, another bucket buffer is sequentially searched for, and after searching for the bucket buffer 33M1, the process returns to the bucket buffer 331. If there is no intra-network packet to be sent, set the packet indication bit Pft to logical value 10'' on the output highway 4.The NB 5 extracts the intra-network packet from the output highway 4 according to the backcut indication bit P. In the packet reproducing circuit 51, the packets are classified by source number 0, stored separately for each source number O, and reproduced into original packets.The reproduced packets are outputted from the output terminal 53 for packet exchange. In this way, the packets divided into intra-network packets by NAl and transferred via 8Wa are
They will be played back in order in B5.

(Effects of the Invention) As is clear from the above explanation, according to the circuit switching switch with a packet switching function of the present invention, by adding a packet switching function to a time division space switch, it is possible to Even though there is no bus that directly connects the switching equipment and the destination packet switching equipment, all time slots not used for circuit switching can be used for packet transmission, so the utilization rate of input highways and output highways can be reduced. This has the effect of increasing the In addition, the input highway,
Output highways can transmit packets independently, which not only simplifies control, but also allows packets to be divided into smaller intra-network packets, compared to the case where one packet is completely stored and then transferred. This has the effect of reducing transmission delay time.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the circuit switching switch with backt switching function of the present invention, and FIGS. 2 and 3 are examples of the input highway/output highway signal format and the intra-network packet format in FIG. 1, respectively. FIG. In the figure, l... Sending side Bakut exchange device N
As2...Input highway, 3...Time division space switch sw, 4...Output highway, 5...Destination side packet switching device NB, 11.
...Input end packet detection and analysis circuit for circuit switching, 3
31.332, ~33M...Packet buffer, 34...Line selector, 35...-Packet selector, 51...Packet reproducing circuit,
52... Output terminal for line exchange, 53...
・Output terminal for packet exchange.

Claims (1)

[Claims] an intra-network packet creation circuit that divides the packet and reconfigures it into short intra-network packets; a changeover switch that selects either the intra-network packet or the circuit switching data; and the intra-network packet that has passed through the changeover switch. Means for branching before the time-division space switch when passing through the time-division space switch, extracting and accumulating the packet, and inserting the accumulated intra-network packet into an empty time slot on the outgoing highway of the time-division space switch. 1. A circuit switching switch with a packet switching function, comprising: a time division space switch having a packet switching function; and a packet regeneration circuit that receives and stores the intra-network packets on the outgoing highway and returns them to the original packets.