JPS59212052A - Communication network control system - Google Patents

Abstract

PURPOSE:To relay a packet by a fixed path selection system by relaying normally the packet by an adaptive path selection system, and resetting a flag when the number of relay stages provided to the header part of the packet exceeds a specific value. CONSTITUTION:The packet 1 arrives at a packet exchange PSA by a loop phenomenon, and when the number of relay stages specified in the header part 6 exceeds the specific value, the flag which indicates the adaptive path selection system in the header part 6 of the packet 1 is reset. Then, a trunk line TLAB which is the 1st candidate for addressee address information on an addressee is selected to relay the packet 1. Similarly, a packet exchange PSB relays the packet 1 to a trunk line TLBC and a packet exchange PSC relays the packet 1 to a trunk line TCCD, so that the packet 1 arrives at a packet exchange PSD which is an addressee.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention uses a route selection method that determines the route to be relayed based on the destination of a packet in a packet switching network.
This invention relates to a communication network control system that relays packets.

Conventionally, there has been a communication network control system for this type of packet switching network as shown in FIG. FIG. 1 is a schematic configuration diagram showing a packet switching network to which a conventional communication network control method is applied. In the figure, PSA, PSnt P
Sc! + PSo, Psi, PSr are
Each trunk line TLAB, TLac + TLca +
A packet switching center is composed of TLAt, TLEF, and TLFD, and 1 is a packet.

FIG. 2 is a block diagram showing packets input to the packet switching network of FIG. 1. In the figure, a packet 1 is Wt-Fitted from a header part 2 having destination address information, the number of relay stages, etc., and data 3. Conventionally, a packet 1 is sent to a packet switching network.・Route selection methods that can be used include the fixed route selection/hole method, which selects a predetermined relay route for each packet destination; :There is an adaptive route selection method that selects the relay route that is expected to take the least amount of time to reach the destination terminal. .

FIG. 3 is a configuration diagram showing a route table in a conventional fixed route@rental method. In the figure, 4#-i, each destination address information B, C, D, E, F and each relay circuit a TL
This is a route table that displays AB r TLAE.

As shown in FIG. 1, when the packet switching station PS receives a packet 1 having destination address information for identifying the destination in the header section 2, it selects the trunk line TLAB based on the route table 4 shown in FIG. and relays the packet l.

Similarly, the packet switching center PSB transmits relay circuit #l TL
nc and the packet switching Ji6 PSc relays the packet 1 to the trunk line TLcn, respectively, so that the packet 1 reaches the destination packet switching center PSD. In the fixed route selection method described above, for example, the trunk line T
If the LAn is congested with other packets, the transfer delay time for packets from the packet switching center PSA to the packet switching center PSo will increase.
.

Figure 4 1° is one of the conventional adaptive route selection methods5
1 is a configuration diagram showing a route table in the case of the HORTEST-QUK method. In the figure, 5 indicates each destination address information B, C, D, E, F and each trunk line TLan +'r.
This is a route table displayed by LaE"C. As shown in FIG. 1, when the packet switching center PsA receives a packet 1 having destination address information for identifying the destination in the header part 2, the packet switching center PsA displays the route shown in FIG. According to Table 5, first, each trunk line TLAIl and TLA are selected as all candidates, and the trunk line TLAE, for example, which has a small number of packets waiting for transmission, is selected and packet 1 is relayed.

Similarly, the packet switching center PSE uses the trunk line TLEF.
Then, the packet switching center PSF relays the packet 1 to the relay line TLrn, and thereby the packet 1 reaches the destination packet switching center Pslin. As mentioned above. [Adaptive route] In the l selection method, for example, if the trunk lines TI and EF are congested with other packets, the packet switching center Ps
i) or the packet is relayed by the relay circuit i1W TLA, so that the packet is transferred to the packet switching center PS
A loop phenomenon in which the data is returned to A may occur. In a packet switching network, if there is a possibility that a loop phenomenon may occur, when relaying the packet switching station IT bucket 1, the relay stage counter in the header part 2 of packet 1 is incremented by +1, and the number of relay stages is increased by +1. When a certain specified value is exceeded, the packet is discarded. As described above, the adaptive route selection method described above has the disadvantage that although packets can be transferred with a small delay time, the packets do not necessarily reach the destination packet switching center reliably.

This invention was made in order to eliminate the drawbacks of the conventional ones as described above. At the packet switching center, a flag indicating an adaptive route selection method for relaying using a relay path that is expected to take the shortest time to reach the destination terminal is added to the [ζζkerat header section], If the number of relay stages added to the Kent header section exceeds a certain specified value,
The flag is reset, the packet is relayed by selecting a relay route using a fixed route selection method in which the packet is relayed using a prescribed relay route instead of the adaptive route selection method, and the packet is relayed. The purpose of the present invention is to provide a communication network control method that can reliably transfer packets to a destination terminal without delay.

An embodiment of the present invention will be described below with reference to the drawings. Fifth
The figure is a configuration diagram showing a packet applied to a communication network control system according to an embodiment of the present invention.

In the packet configuration diagram shown in FIG. The route table for packet 1 shown in Figure 5 is the same as in the case of the adaptive route selection method shown in Figure 4 above, except that the order of the relay route to the destination is They differ in that they have meaning.

Next, the operation of the communication network control system of the present invention described above will be explained using the packets shown in FIG. 5, the conventional packet switching network shown in FIG. 1, and the route tape shown in FIG. 4. . As shown in Figure 1, the packet switching center PSA
When receiving a packet 1 having a header section 6 with destination address information for identifying the destination shown in FIG. 5 and a flag indicating an adaptive route selection method, the route table 5 shown in FIG. , each trunk line 'rt, An
l TLAE is selected as a candidate, and packet 1 is relayed by selecting, for example, a relay line TLAE with a small number of packets waiting to be transmitted. Similarly, the packet switching center PSE sends one packet to the trunk line TLEF, and the packet switching center PSF sends one packet to the trunk line TLFD.
As a result, the packet 1 reaches the destination packet switching center PSD. If packet 1 reaches the packet switching center PSA due to the loop phenomenon described above, the header section 6
If the number of relay stages exceeds a certain specified value, the flag indicating the adaptive route selection method in the header section 6 of the packet 1 is reset. Then, based on the route table 5, the relay direction IV TLAB which is the first candidate for the destination address information identifying the destination is selected and the packet 1 is relayed. Similarly, the packet switching center PSn
nc, the packet switching center PSc connects the trunk line TLCD.
The packet 1 is thereby relayed to the destination packet switching center PSn.

In the above embodiment, 5H is used as the adaptive route selection method.
Although the ORTEST-QUE method has been described, 7- Other adaptive route selection methods, such as 5HORTEST-QU
An E-bias method may also be used. Furthermore, depending on the type of information, the present invention can also be applied to a packet switching method for switching the route selection method described above.

As described above, according to the communication network control method of the present invention, in a packet switching network, a flag is added to the header of a packet transferred from a source terminal to a destination terminal, and the adaptive route selection method and fixed When the number of relay stages added to the header of the packet exceeds a certain value, the flag is reset and the fixed route selection method is used in combination with the route selection method. Since the configuration is configured to relay packets, it is possible to reliably transfer packets to the destination terminal with very little delay time, and it is also extremely stable compared to conventional communication network control methods of this type. This has the excellent effect of providing a route selection method for a packet-switched network with high performance.

[Brief explanation of the drawing]

FIG. 2 is a schematic configuration diagram showing the packet switching network of FIG. 1; FIG. 3 is a configuration diagram showing the route table in the conventional fixed route selection method; FIG. The figure is a configuration diagram showing a route table for the 5HORTEST-QUE method, which is one of the conventional adaptive route selection methods, and FIG. 5 shows packets to which the communication network control method is applied, which is an embodiment of the present invention. FIG. In the figure, PSA, PSB + PSC, PSn
, PSE. PSp packet switching center, TLAB+ TLRC+
TT7CD + TLABITLEF * TLFD
. . . Relay line, B, C, D, E, F. Destination address information. ■. Packet. 2.6. Header section. 3. Data. 4.5. Route table. In addition, in the figures, the same reference characters indicate the same or equivalent parts. Agent: Masuo Oiwa, 1st cause, 2nd cause, 3rd figure, 5th procedural amendment (spontaneous) 59613 Showa year, month, day 1, case description Patent Application No. 58-86969 2, title of invention Communication network control method 3 , Supplementary IF - [5, Subject of amendment: ``Detailed Description of the Invention'' column of the specification. Contents of the amendment (1) “Bias” in the second line of page 8 of the specification has been changed to “
bias” and correct it.

Claims (1)

[Claims] In a packet switching network where a packet transmitted from a source terminal is transferred to a destination terminal by relaying through multiple packet switching stations, a relay route that is expected to take the shortest time to reach the destination terminal. A flag instructing an adaptive route selection method for relaying using 1. A communication network control method, characterized in that, instead of an adaptive route selection method, a fixed route selection method in which a prescribed relay path is used for relaying selects a relay path and relays the packet.