JPS59228447A - Transfer system in packet network - Google Patents

Abstract

PURPOSE:To perform the transfer of a long packet in the same delay time as that for a short packet by giving precedence to the inter-network transfer processing without awaiting the end of reception of all segments of all packets. CONSTITUTION:A segment reception circuit divides a reception packet into plural segments when the packet is a long message. A packet header checking section 2 conducts the header check by the reception of the 1st segment, gives a sequence number 0 and conducts the transfer processing in preference to other processings. When succeeding segments are received, a header is given by a header editing section 3, and the transfer processing is conducted by the inter- network transfer section 4. When a reception error exists, an abolishing request signal is given to a station processed already from the abolishment command section 9 and the internal state of the own station is restored by an internal state restoring section 10.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) 0 Technical Field of the Invention The present invention relates to a packet intra-network transfer method, and particularly relates to a method for intra-network transfer of long packets in a packet switching method.

(b), Prior Art and Problems The packet switching method is a method in which a message to be communicated is divided into data blocks, and the packets with other headers such as destination and serial number are transferred at high speed via a storage and switching device. be.

According to conventional technology, when transferring long packets within a data exchange network, the relay station performs the necessary processing after receiving all the packets, and then transmits them to the subsequent station.
A drawback is that the transmission delay time increases each time the number of relay stages in a packet switching network increases.

(C)3 Objectives of the Invention The objectives of the present invention are to eliminate the above-mentioned drawbacks of the prior art;
Long packets with the same delay time as regular short packets
The object of the present invention is to provide a packet transfer method within a network that can transfer packets.

(d)0 Structure of the Invention According to the present invention, in a packet switching system, when a long packet from a user is transferred within a network, all the packets are divided into a plurality of segments, and the This is achieved by providing a packet intra-network transfer method characterized in that intra-network transfer processing is preceded by the completion of reception of some segments of the packet without waiting for the completion of reception of all segments of all packets. Ru.

Further, in the packet intra-network transfer method, the receiving station performs a waiting process until all the segments arrive; In the packet intra-network transfer method characterized by having a packet discard instruction signal as a process when a reception error occurs, and the above-mentioned packet intra-network transfer method, the timing until the receiving station completes reception of all the segments. This is achieved by providing an intra-network packet forwarding method that takes the following steps and initializes the communication link in case of a timeout.

(e) 0 Embodiment of the invention The present invention attempts to reduce the transfer delay within the network to the same level as short packets by dividing the long packet to be transferred into multiple segments and then transferring the packets. It is something.

FIG. 1 is a diagram showing user data (including a header) that is transfer information according to an embodiment of the present invention.

In FIG. 1, the shaded area is a header, and (2) to in) indicate user data divided into n pieces including the header.

Figure 2 is a diagram explaining the operation at the transmitting station;
The figure is a diagram explaining the operation at the receiving station.

In the figure, TA is a transmitting terminal, TB is a receiving terminal, 1 is a segment receiving circuit, 2 is a packet header check unit,
3 is a packet network header editing section, 4 is an intra-network transfer section, 5 is an intra-network reception circuit, 6 is a waiting control section, 7 is a long packet assembly section, 8 is a sending circuit, 9 is a discard instruction section, and 10 is a Internal status light return section 11 indicates a waiting discard section.

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

A segment receiving circuit 1 in the transmitting station shown in FIG. 2 receives the packet from the transmitting terminal TA.

Note that the longest short packet received here is the long packet.
The packet is segmented and specified to be longer than the longest segment that can be created.

When the segment receiving circuit 1 determines that the received packet is longer than the specified length (the longest short packet received),
(when the length is longer than the packet), the first
Divide into multiple segments as shown in the figure.

First, the case of normal processing when receiving a packet from the originating terminal TA will be explained.

The segment receiving circuit 1 of the transmitting station divides the received transfer data into a plurality of segments as shown in FIG.

Regarding the +11 segment shown in Figure 1, the header is checked upon completion of reception of this segment, and if it is normal, the packet header check unit 2 displays a long packet and the sequence number "O" in the packet. The transfer process is performed in advance.

When a subsequent segment (2) and subsequent segments shown in FIG. The intra-network transfer unit 4 then performs transfer processing.

Incidentally, the sequence number is sequentially incremented by 1 starting from the first "O".

At the time of the final segment, the intra-network header editing section 3 adds an intra-network header containing an indication of completion of packet reception, and transfers it to the same destination via the intra-network transfer section 4.

When this result is transferred from the originating station via a relay station, the individual segments at the relay station are
It is relayed and transferred in the same way as packets.

Next, at the receiving station, the segmented packets received by the in-network receiving circuit 5 are ordered by the waiting control circuit 6.

When all n segmented user data packets are received, the long packet assembling unit 7 restores the original long packet, and the transmission circuit 8 transfers it to the user terminal TB.

Next, the case where the frame reception error is NG will be explained.

If there is a reception error in the frame shown in FIG. 1, a packet discard request signal is transferred to the station that is already processing it.

If the station that is already processing is, for example, the originating station (indicated by the dotted line in FIG. 2), the discard instruction unit 9 transmits a packet discard request signal to the destination station, and the internal state restoration unit 1
0 returns the internal state of the local station to its original state. The destination station receives this packet discard request signal and discards the segmented packets that have already been transferred and are being rescheduled by the rendezvous discard unit 11.

The originating station transfers the retransmitted frame within the network from the beginning.

In this manner, when an abnormal NG occurs, the packet is transmitted again and accurately.

Also, in the present invention, it is naturally possible to consider a method in which only the segment in which the error occurred is transferred instead of starting over from the beginning as described above when the frame reception error is NG.

Furthermore, the receiving station can measure the timing from the arrival of the first segment and initialize the communication link as a timeout if reception is not completed within a predetermined time.

(f) 0 Effects of the Invention As described in detail above, the present invention has the great effect of making it possible to transfer long packets with the same delay time as normal short packets.

[Brief explanation of the drawing]

FIG. 1 is a diagram illustrating user data (including headers) according to one embodiment of the present invention. In FIG. 1, the shaded area is a header, and (2) to (n) indicate user data divided into n pieces including the header. Figure 2 is a diagram explaining the operation at the transmitting station;
The figure is a diagram explaining the operation at the receiving station. In the figure, TA is a transmitting terminal, TB is a receiving terminal, 1 is a segment receiving circuit, 2 is a packet header check unit,
3 is a packet network header editing section, 4 is an intra-network transfer section, 5 is an intra-network reception circuit, 6 is a waiting control section, 7 is a long packet assembly section, 8 is a sending circuit, 9 is a discard instruction section, and 10 is a The internal state restoring section 11 indicates a waiting discarding section. Number? [

Claims (1)

[Claims] 1. In the packet switching system, long
When transferring a packet within a network, all the packets are divided into a plurality of segments, and intra-network transfer processing is performed upon completion of reception of some segments of the packet without waiting for completion of reception of all segments of all the packets. A packet intra-network transfer method characterized by preceding. 2. The packet intra-network transfer method according to claim 1, wherein the receiving station performs a waiting process until all the segments arrive. 3. In the above-mentioned packet intra-network transfer system, a packet discard instruction signal is provided as a process when a reception error of the segment occurs.
Packet intra-network transfer method described in section. 4. In the above-mentioned intra-network transfer method, timing is taken until all the segments have been received at the receiving station, and the communication link is initialized in the case of timeout. The packet intra-network transfer method described in Section 1.