JPH01196940A - Packet multiplex communication system - Google Patents

Abstract

PURPOSE:To prevent the production of the reversed sequence of packets at the arrival node by selecting one among virtual line bundles of a semi-fixed route for each call at calling, transferring a packet according to the selected fixed route and using an identifier (VPI) so as to identify the output path of the received packet. CONSTITUTION:If virtual paths A, B exist between an outgoing exchange 2 and an incoming exchange 4 and an idle capacity exists in a call set phase, to which virtual path of the paths A, B the packet from a packet sender terminal equipment 1 is decided according to a prescribed algorithm and its information is written in the routing table of the call controller of the sender exchange 2. On the other hand, in each relay node, the VPI only in a head is identified and an outgoing link is selected according to the routing table in the relay node controller 9 written at the virtual path setting to transfer the packet. Thus, the reversed sequence of the packet between packets belonging to one call is prevented in the arrived node.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an efficient packet multiplex communication system.

(Prior Art) DDX-P has been put into practical use as a conventional packet multiplex communication system. In that case, the intra-network transfer method for packets is a method in which each packet is processed independently within the network, in other words, each packet is relayed and transferred according to the route selection algorithm at that time at the relay node where the packet is relayed. The datagram method was used.

(Problem to be Solved by the Invention) In such a system, the route to be relayed may be different for each packet belonging to one call, and the order of packets may be reversed at the arrival node, which requires recovery processing. There was a drawback.

In addition, when selecting a route within the network, the most common method is to search for routing multiples at relay nodes using the number (NOC) assigned to the destination exchange specified in each packet, and then select the outgoing route. It was getting worse. This type of system has the disadvantage that it is generally not possible to distribute relay routes for each originating exchange or for each call because what the relay node recognizes is simply the destination exchange number. . The reason for this will now be explained with reference to FIG. 2, which shows a conventional packet network. In FIG. 2, 1 is a packet originating terminal, R and S are originating exchanges, T is a destination exchange, and α, β, T, and δ are relay node devices. In other words, as shown in FIG. 2, when packets between relay node equipment α and β are multiplexed on the transmission path, packets destined for destination exchange T at relay node equipment β are also transmitted from originating exchange R. This is because it is not possible to distinguish whether the signal comes from the originating exchange S, that is, the route [phase] or the [phase]. Here, if a method is used in which fixed-capacity buses are allocated to each switch R and S by time division multiplexing without packet multiplexing on the transmission path between relay node devices α and β, each path capacity becomes smaller. , relay no.

This method has the disadvantage that the large grouping effect obtained when multiplexing packets is smaller than when packets are multiplexed between the card devices α and β. On the other hand, when trying to identify the originating exchange with a relay node device, in addition to the NOC, an identifier (VPI: Virtual Path Ident) that identifies the virtual line bundle (Virtual Path) between the exchanges is used.
if'1er) must be added to the header of each packet, which has the disadvantage of increasing header overhead.

(Means for Solving the Problems) In order to eliminate these drawbacks, the present invention uses a virtual, semi-fixed route that is preset between packet exchanges for each call when a call is made as an intra-network transfer method for packets. One of the line bundles is selected, the packet is transferred according to the selected fixed route, and the relay node between the exchanges identifies the outgoing route of the received packet using an identifier (VPI). .

(Embodiment) FIG. 1 shows an embodiment of the present invention, in which 1 is a packet originating terminal, 2 is an originating local exchange, 3 is a relay node device, 4 is a terminating local exchange, 5 is a subscriber transmission line, 6 is a relay transmission path, 7 is a network termination device, 8 is a subscriber exchange call control device, 9 is a relay node control device, and 10 is a packet destination terminal.

Further, FIG. 3 shows an example of the structure of a packet used in the embodiment of the present invention. ll is the header part, and the header part is CI (
Call Identifier) and vpr, and CI.

It consists of a header section 12 other than vP■, which includes a service class display, an error detection code for the header section, etc., and 13 is an information section.

The packet length may be fixed or variable.

As an example, FIG. 1 shows a case where two virtual paths A and B exist between the originating exchange 2 and the destination exchange 4. In the call setup phase, the exchange recognizes the free capacity of the birch route path, and if there is free capacity, determines whether to accommodate the packet from packet originating terminal 1 on either virtual path A or B according to a predetermined algorithm. The information is then written to the routing chip in the call control device of the originating exchange.

Table 1 Example of originating exchange rooting team Originating exchange 2
Table 1 shows an example of the routing cheap in the call control device.
Shown below. When a call is set up, the packet originating terminal 1 or the network terminating device 7 packetizes the information, assigns a CI to each packet, and sends it out to the network. CI is a number assigned to each terminal or logical channel number (LCN: Lo
channel number).

The originating local exchange 2 recognizes the CI of the input packet and writes a VPI to each packet according to the routing chain within the local exchange call control unit 8.

Table 2 Example of Routing Group for Relay Node Control Device On the other hand, each relay node identifies only the VPI in the head shown in FIG. Luci Ing Chi
The outgoing link is selected according to the pull (as exemplified in Table 2), that is, the relay node transfers the packet without performing call control for each call connection at the node. The way to assign VPI to achieve the above is as follows:
There are two methods: (1) giving a number in advance to a device in a passing corner node and displaying it as a VPI; (2) giving an identifier indicating a route connecting a specific relay node device in a relay node to be passed. A conceptual diagram of the above method (2) is shown in FIG.

FIG. 4 is an explanatory diagram of identifier setting indicating a route connecting specific relay node devices in a relay node, where nodes λ and μ each have 2 units of relay node devices λ-1.
, λ-2 and μm11μm2, and λ-1 and μ
m1 is the transmission line 14-■, λ-2 and μm2 are the transmission line 14
- It is assumed that they are connected by ■. Here, the VPI for the bus passing through the relay node equipment of λ-1 of node λ and μm1 of node μ is a1, and the VPI of the bus passing through the relay node equipment of λ-2 of node λ and μm2 of node μ is b. give. In this case, the content of the VPI in the header of the packet arriving from the input transmission path connected to the node device λ-1 is
Those with VPI a are transferred to transmission line 14-L, and those with VPI b are transferred to transmission line 14-2.

FIG. 5 shows a conceptual diagram of a communication network in which the relay network is divided into several layers. Here, 15 is a relay network, 16 is a subscriber access network, 17 is a local area network or home network, 18 is a long distance relay network, 19 is a regional relay network, 20 is a long distance relay network relay node, and 21 is a local relay network The relay node 22 is a subscriber switching node. In this example, a line bundle (path) that logically connects the relay nodes 21 in the local network 19 directly to the mesh is set up in the long-distance relay network 18 by time division multiplexing or wavelength division multiplexing.

In other words, this means that the time position in the multiplexed frame of the transmission path is fixed for each bus, or that different wavelengths are assigned on the transmission path, and that it is a simple bus that is not a virtual path. It is.

On the other hand, in setting up virtual paths between the subscriber switching nodes 22, the local relay network 19 uses the packet multiplex communication method described in the present invention. As in this example, the relay network can be divided into several layers, and the packet multiplex communication method of the present invention can be used as the relay transmission method within at least one of the layers.

(Effects of the Invention) As explained above, in the communication system described in the present invention, ■A system in which a unique route between subscriber exchanges is assigned for each call using a fixed route selection algorithm at the time of call setting (virtual circuit) Therefore, there is an advantage that the order of packets belonging to one call is not reversed at the arrival node.

■ An identifier (VPI) that makes it possible to identify a virtual line bundle (virtual bus) with a semi-fixed route set in advance between local exchanges is written in the header of each packet at the originating local exchange. Since the outgoing link is selected and the packet is transferred according to the routing cheap in each relay node control device, the relay node does not need call control for each call connection, and the processing within the network during the call setup phase becomes unnecessary. There is an advantage that the amount can be made very small. In addition, in links between relay nodes, virtual paths use time division multiplex transmission frames, rather than using time division multiplexing in which the time position within the frame is fixed. Because packets are multiplexed on the transmission path, a large grouping effect can be obtained on the total transmission capacity, and the advantage is that the required transmission line capacity for a certain line can be reduced compared to when virtual paths are time-divided. be.

Furthermore, by defining a plurality of virtual paths between originating and terminating exchanges in advance, there is an advantage that it is possible to easily distribute relay routes for each originating exchange or for each call.

[Brief Description of the Drawings] Figure 1 shows an embodiment of the packet multiplex communication system of the present invention, Figure 2 shows a conventional packet network, and Figure 3 shows packets used in the packet multiplex communication system of the present invention. Fig. 4 is an explanatory diagram of an identifier setting indicating a route connecting specific relay node devices in a relay node, and Fig. 5 is a conceptual diagram of a layered communication network. . 1... Packet originating terminal 2... Originating local exchange 3... Relay node device 4... Destination local exchange 5... Subscriber transmission line 6... Relay transmission line 7.
...Network termination device 8...Local exchange call control device 9...Relay node control device 10...Packet destination terminal 11...Header part 12...Header part 13 other than CI and VPI... - Information section 14... Transmission line 15... Relay network 16... Subscriber access network 17...
Local area network or home network 18...Long distance relay network 19...Regional relay network 20...Long distance relay network relay node 21...Local relay network relay node 22...Subscriber switching node

Claims (1)

[Claims] 1. In a packet multiplex communication system in which packets are transferred by packet multiplexing via a plurality of relay nodes between originating and incoming packet switching devices, as a method for transferring packets within the network, one or more of the The packets are transferred according to a predetermined route between the packet switching equipment uniquely selected from the packet switching equipment, and individual packets are identified on a call-by-call basis at the packet originating terminal, packetization device, or packet originating switching equipment. A call identifier (CI) is assigned in the header, and one or more relay nodes are set between the exchanges in the packet originating terminal, the packetizer, or the packet originating exchange that accommodates the packet originating terminal. Virtual line bundle with semi-fixed route (
An identifier (VPI) is added to the header of the packet, and intermediate relay nodes consider only the identifier (VPI) in the header, and each time a call is connected at the relay node. Without performing call control, the packet is sent to a predetermined outgoing route according to the outgoing route identification information that is compared with the identifier (VPI) shown in the routing table in the relay node in advance, and the logic between the originating and terminating exchanges is A communication system characterized by accommodating virtual paths stretched in a mesh into a transmission line network via one or more relay nodes, and multiplexing packets on the transmission line. 2. Claim 1, characterized in that the packet is given an identifier (VPI) indicating a route connecting one or more relay nodes passing through between the originating and terminating exchanges, or a specific relay node device in the relay nodes passing through. packet multiplex communication method. 3. Divide the relay network into several layers, and at least one of them
A packet multiplex communication system, characterized in that the packet multiplex communication system according to claim 1 or the packet multiplex communication system according to claim 2 is used as a relay transmission system within two layers.