JPH0348554A - Packet switchboard - Google Patents

Abstract

PURPOSE:To efficiently use a connection network by setting a single route in unit of call of the route with a switch route setting processor when a node route setting processor selects the route. CONSTITUTION:The node route setting processor 14 makes access a module link working table 16, and discriminates the route with the highest allowance on a traffic, and sets a switching module SM 12 and a rank included in the route of the connection network 10 of a switching machine 60. The switch route setting processor 30 of the SM 12 receiving an instruction judges whether or not the setting of the route in a switch is feasible, and reports the feasibility/ infeasibility of the setting of the route to the processor 14. The processor 14, when receiving a report feasible to perform the setting of the route, instructs the change of a routing header correspondence table 32 and a switch link working table 34 to the processor 30, and changes its own working table 16. Thus, the single route can be set in unit of call when a call is set.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a packet switch, and particularly to a packet switch having a connection network whose components are unit connection networks that transfer packets with routing headers added thereto. (Prior art) A switch in a switching node of a communication network has a multi-stage connection of unit connection networks (switching modules) with N inputs and N outputs, and each switching module also has a path connecting arbitrary inputs and outputs within the same module. Some devices have a multi-stage connection configuration of 2-input x 2-output switches, that is, binary switches, which can be set in multiple numbers.

When setting up a route between terminals in such a communication network, first select a transit node exchange, then select a transit switching module for each connection network of this selected exchange, and finally select the selected switching Configure routes within the module.

A paper explaining the internal route setting of a conventional switch includes ``Prototype production of an AT&L switch for broadband ISDN'' by Yuji Kato et al., IEICE technical report tN88-22 (19881).
There is. The multi-stage self-routing exchange scheme described herein is based on its r3 Multi-Stage Self
As can be seen from the ``3.l principle'' of ``-Routing Switching System,'' the routes are set so that the traffic on each link between the switching modules (SR & 4 in the same paper) is equalized, taking into account the burst nature of calls. The information on the set route is transferred to 1 by transferring the TAG (call route path information) and updating the VCI (virtual channel identifier).
1 purchase has been made.

(Problem to be Solved by the Invention) Packet switching equipment has the problem of how to distribute various traffic from multimedia that is added to a connection network to each link in the connection network.

In the above-mentioned conventional technology, the usage amount, that is, the bandwidth, is allocated by taking burstiness into consideration when setting the route.
6 When performing routing of various calls with different characteristics, it only takes into account its own burstiness.
The overall traffic characteristics of calls carried over the link are:
It is necessary to consider not only the characteristics of a single call, but also how many calls with which characteristics are collected. Therefore, traffic characteristics cannot be accurately reflected in route setting just by considering the burstiness of the network itself.

In the conventional system, the transmission path for user information and the transmission path for TAG are different, so the hardware configuration is complicated and the system lacks expandability. The purpose of the present invention is to solve this problem and provide a packet switch that allows various traffic to be distributed more appropriately to each link and allows efficient use of the connection network. (Means for Solving the Problems) In order to solve the above-mentioned problems, the packet switching equipment according to the present invention integrates the traffic data of packets being transmitted in the connection network and the characteristics of new traffic, and It is configured to set the packet route. More specifically, the packet switch according to the present invention is connected between a plurality of input terminals to which packets are input, a plurality of output terminals to output packets, and a plurality of input/output terminals, and a unit connection network (switching module) as a component, which includes a connection network in which multiple stages are connected by noncs between the stages, and a unit connection network and link that transfers a packet input to the connection network to one of a plurality of output terminals. a first route setting means for selecting one of the plurality of routes; the unit connection network has a plurality of input means for adding a routing header to an input packet; and a plurality of outputs for outputting the packet. means, a switch network having a plurality of paths connected between the plurality of input means and the plurality of output means, for forwarding an input packet to one of the output means according to its routing header; A second method that selects one of the plurality of routes for each call to which the packet belongs and creates a routing header that is route information.
The first route setting means has a second route setting means.
The route setting means is instructed to set and release a route.

(Function) According to the present invention, the first route setting means selects one of the transferable routes in the connecting network for each call to which the packet belongs, and The second route setting means sets a route for each call to which the packet belongs in the switch network of the unit connection network in response to the instruction from the first route setting means. This causes the switch to forward packets of a particular call to the same route.

(Example) Next, an example of a packet switching device according to the present invention will be described in detail with reference to the attached drawings. Figure 1 shows an embodiment of a packet switching system according to the present invention. Packet switch 6 of this embodiment
0 has a connection network IO consisting of a unit connection network (switching module SM) l2 whose inputs and outputs are each a natural number N. When a packet call connection request occurs, the packet switch 60 sets a route for transferring the packets of the call. Each switching module l2 on the path adds a routing header RH to the input packet P (FIG. 2) and forwards it. The packet switch 60 functions as the switching node 5 that performs the packet communication network I illustrated in FIG.

The switching node 5 is connected via a transmission line 6 to other nodes 5 or to a user network interface (UNII 4).The interface 4 accommodates various types of terminals 2, such as telephone, image, data, etc. , terminal 2
This is an interface device that packetizes the signals from the node and sends them to the switching node 5, and also receives packets from the node 5, converts them into signals suitable for the End Song 2, and outputs them to the terminal 2. When one of the terminals 2, for example, a calling terminal a, sends a communication request to a call processing processor 20 (to be described later), the processor 20 sends a communication request from the calling terminal a to the UNI 4 to the switching node 5.
．． ．． ．． ．． A communication path from exchange node 5 to UNI 4 to destination terminal b is set up, and communication between both terminals a and b is performed via this.

The packet switching island 60 of the switching node 5 has a connection network lO illustrated in FIG.
・8) The number of stages in which G switching modules 12 having input/output terminals are arranged is a natural number H (for example, H: 3).
This is a connection network in which multiple stages are connected by links between modules.
Therefore, there are (H-1) sets of links between stages.

Input terminal NOO. of connection network IO. NO1,. ．． ．． ,NO
G-1 is connected to the input transmission line, and output terminal NIO. Nl1
,．． ．． ．． ．． NIG-1 is connected to each output transmission line. A node route setting processor 14 is provided corresponding to the connection network IO, and this is a processing device that is controlled by the call processing processor 20 via the control line 8 and sets a route within the connection network IO. The route setting processor 14 is provided with and can access a module link usage table 16 in which the amount of inter-module links used, as well as the type and number of calls being transmitted are registered.

The call processing processor 20 is provided in common in the plurality of exchanges 60, receives an outbound signal from the terminal 2, gives an instruction to the node route setting processor 14 to set a route within the connection network, and also determines whether or not the route can be set. This is a call processing device that receives reports. In this embodiment, the switching module 12 is, as shown in FIG. It consists of a Benes net 26. The input of the switch network 26 is connected to information addition units fRA1 40 to 47, and the output is connected to information deletion units (RBI 50 to 57. Information addition unit 4
0 to 47 are functional units that are connected to the input transmission path or the link of connection [0, and add route information for routing within the switch, that is, a routing head PH, to the input packet P. The information deletion units 50 to 57 delete this routing header RH from the packet P that is connected to the output transmission path or the link of the connection network IO and transferred through the switch network 26.
This is a functional section that removes.

The switching module l2 has a switch routing processor 30 which is connected to and under the control of the node routing processor l4 of the exchange 60. The switch path processor 30 is connected to the switch network 2
This is a processing device that executes route settings within 6. The switching module l2 has a header correspondence table 32 and a switch link usage table 34. The former 32 is a table that records the correspondence between logical channel numbers of calls and route information, and each of the information adding units 40 to 47 can access this via the connection 1i148. The latter, ie, the switch link usage table 34, is a table that registers the amount of link usage within the switch network 26, the type of call being transmitted, and the number of calls. Both tables 32 and 34 can be accessed by switch routing processor 30. The switch network 26 includes four binary switches IBsW in each stage.
It consists of 5 switch stages (number of stages n=5) consisting of I22. Therefore, the number of links between the stages is 8, and the information addition units 40 to 47 and the information deletion units 50 to 5
There are 4 sets of paths each consisting of a binary switch 22 and a link connecting any of the 7 binary switches 22, and the 6 binary switches 22 are unit switches each having 2 inputs and outputs, and a buffer and a switch processor (not shown). has. The switch processor stores the input packet P in a buffer and outputs the packet P to the link indicated by the routing header RH. By the way, when the call processing processor 2 receives a connection request from the calling terminal a, it receives this as an outband signal. This signal includes the originating address, the terminating address, and information such as burstiness, average usage, allowable delay time, and allowable packet loss rate as required quality declaration values. In response to this connection request, the call processing processor 20 selects the exchange 60 of the exchange node 5 as the communication route, and sends a control signal to the node route setting processor l4 via the connection line 8.

The node route setting processor l4 refers to the module link usage table 16, and selects the switching included in the route in the connection network IO that connects the human output terminals Ni and Nj of the exchange 60 so that the traffic is divided evenly. The module l2 and the link are set, and the input/output terminal i to be connected to the switch route setting processor 30 is determined based on the setting result.
and, indicate j. Upon receiving the instruction, the processor 30 determines whether or not the switch internal route can be set, and reports whether the route can be set to the node route setting processor l4.

If there is a report that setting is not possible, the input/output terminal to be connected is instructed to each switch route setting processor 30 belonging to another route in the connection network. If a route cannot be set within the connection network, a request is made to the call processing processor 20 to select another exchange. If the node route setting processor 14 receives reports from all the instructed switch route setting processors 30 that the route can be set, it reports to the call processing processor 20 that the route within the connection network can be set.

The module link usage table 16 used by the node route processor l4 includes the usage amount of the inter-module link connecting the switching module l2 at a certain stage in the connection network lO of the exchange 60 and the switching module l2 at the next or previous stage, as well as the amount of usage of the inter-module link. The type of call and number of calls being transmitted over the link are recorded. More specifically, as illustrated in FIG. 4A, the usage status of all inter-module links in the connection network IO is stored. As shown in FIG. 48, the contents of the table include the label and usage amount of each link for all links, as well as the already set call types A-Z. j5 and number of calls a
- z is recorded. Call types are registered by classifying calls based on burstiness, average usage, allowable delay time, and allowable packet loss rate, with calls as required quality declaration values. Change these data as follows. First, when setting up a call, the amount of usage allocated by the node route setting processor l4 for the set call is added to all links belonging to the set route in the module link usage table 16, and the call type and number of calls are registered at the same time. do. In addition, when releasing a call, the usage amount allocated by the node route setting processor l4 to the call to be released is subtracted from all links belonging to the set route, and the call type and number of calls are deleted from the registration. do.

In the switch link usage table 34 used by the switch path processor 30, as illustrated in FIG. 5A, the contents of six tables storing the usage status of each link in the switch network 26 are as shown in FIG. 5B. Labels and usage amounts indicating each link within the switching module, as well as records regarding the call origin and number of calls already set during transmission, are classified in the same way as the inter-module link usage amount (Figure 4B) described above, and are used between switches. This is recorded as link usage. When setting up a call, the switch route setting processor 30 adds the amount of usage allocated to the call to all links belonging to the set route in the switch link usage table 34, and simultaneously registers the call type and number of calls. When a call is released, the usage amount allocated to the call is decremented from all links belonging to the set route, and the call type and number of calls are deleted from the registration. If the route setting within the connection network 10 is possible, the node route setting processor 14 instructs the switch route setting processor 30 to change the header correspondence table 32 and change the switch link usage table 34 in response to an instruction from the call processing processor 20. and change its own module link usage table 16. The switch routing processor 30 includes:
One of the multiple routes that can be set is selected using the method described below, and a routing header RH that is the logical value of that route is created. In the header correspondence table 32, as an example is shown in FIG. 6, the values of the routing headers RH are recorded in correspondence with the logical channel numbers #0 to IOIAX of the call. The switch route setting processor 30 changes the value of the routing header RH to a value corresponding to the selected route.

When a packet P is input to one of the information adding sections 40 to 47, the information adding section extracts a logical channel number from the header section H, and accesses the header correspondence table 32 through the connection 4+i 148. As a result, the value of the routing header RH corresponding to the logical channel number is extracted from the table 32, added to the beginning of the packet P as the routing header RH, and outputted to the switch network 26. The packet P is routed within the network 26 based on the routing header RH and reaches one of the information deletion units 50 to 57. The information deletion unit deletes the added route information, that is, the routing header RH, and inputs the packet P to the next switching module l2. The packet P is routed one after another through the switching module l2 of the set path and is output to the output terminal Nj of the exchange [60].

Next, the connection network route setting algorithm will be explained with reference to FIG. The node route setting processor 14 accesses the module link usage table 16 that registers the usage of all links between switching modules, the type of call being transmitted, and the number of calls, and determines the route with the most margin in terms of traffic. This sets the route for packet P. Routing processor 14 receives instructions to set up or release a call under the control of call processing processor 20 (100).

For call setup, exchange I! 1102) Extracting all routes connecting 60 input/output terminals Ni and Nj. Next, one of the extracted routes within the connection network is selected, and the surplus usage of each inter-module link belonging to that route is calculated using the inter-module link usage table of FIG. 4A (104). Next, find the minimum value of the calculated surplus usage of each inter-module link, and set this as the surplus usage of the route within the connection network (1051. Processes 104 and 105 are performed for all the routes that can be set ( The judgment as to whether or not all routes have been executed is 106).The surplus usage amount calculated by this is ranked by size 11071.At that time, if there are multiple routes with the same amount of usage, one of them is
(1081. Each switch included in the connection network path selected in this way
fll01 sends an instruction to the switch route setting processor 3o of No. 2 to report whether or not the route in the switching module l2 can be set. The switch route setting processor 30 compares the surplus usage in the switching module l2 with the usage allocated to the call, and determines whether setting is possible or not.
Report the results to node routing processor l4. If setting is not possible, determine whether other routes in the connection network have been considered (1121. If not, proceed to step 10).
Return to 8 and 110. If it has been considered, the node route setting processor 14 reports that the setting is impossible to the call processing processor 2o (114). If it is possible to set it in process 110, it reports to the call processing processor 2o that it is possible to set the route in the connection network, and receives an instruction 11161. processor 1
4 is the switch route setting processor 30 in the case of the route setting process 116 or the route release process 100.
to change the header correspondence table 32 and switch link usage table 34, +1181. and changes the module nonk usage table l6 (120+).Here, with reference to FIG. l
4 selects one of the routes within the connection network f2001. Read the usage of all inter-module links belonging to the selected route +2021. Maximum usage amount Mn (g
．． h). and calculate the usage amount Cn (g. h) already allocated to each link (f204). If the call usage allocated to the route to be set is Vn (g.
Calculated by Cn (g. hl +Vn (g. hl) +2061. Extra usage amount of each link Pn (
Let the minimum value of g, hl be MIN f2081. Let this value be the surplus usage of the selected connection network route. In other words, the representative value is the surplus usage of the inter-module link that is the most bottleneck on the inner path of the connection network for which you want to know the surplus usage. The above process is executed for all routes that can connect the input terminal Ni and the output terminal Nj extracted in the process 102 of FIG. 7.

The above-mentioned allocated usage amount Vn (g. h) is determined as follows. Allocated usage amount Vn of the call to be routed
Ig, hl can be calculated as Cd x A, where Cd is the average usage amount issued from the call setup requesting side and A is the coefficient. The relation Hl is determined depending on how many call types the link of interest is transmitting. The more statistical multiple effects can be expected, the smaller the value of the coefficient ffi A becomes. Therefore, the allocation use ffiVnfg. The value of hl may vary depending on the link.

The allocation of maximum usage tQMn (gh) will be explained. The maximum usage of the link of interest 1&ln (g.hl is determined by how many call types are being transmitted using that link. The maximum usage amount un (
g. h) takes a large value. Therefore, the maximum usage I
Mn (gh) may also have different values depending on the link.

If more traffic is added than the amount of usage allocated by the setting of maximum usage itMn (g.hl), the effect of absorbing the excess amount is expected.

In this embodiment, a Benes network is used as the switch network of the switching module l2 that constitutes the connection network lO of the exchange 60, but the present invention is not limited to this, and the switching module l2 may be a network of other types. Even though
It suffices if the route connecting any input/output terminal is a switch network that exists in Win. (Effects of the Invention) As explained above, in the present invention, a single route is set for each call when setting up a call. , The configuration of the pinary switches that make up the switch network is simple, and the temporal order of packets belonging to the same call is not reversed within the switch network. Therefore, the order will not be reversed within the exchange. Further, the configuration is such that a route within the connection network is set by a node route setting processor specific to the connection network, and a route within the switching module is set by a switch route setting processor specific to the switching module. Therefore, the load required for route setting processing is divided.

In addition, in a multi-stage connection network where there are multiple routes connecting arbitrary human outputs, it is possible to apply the link usage amount to 1; It is highly versatile and the hardware configuration for monitoring link usage is simple.

Furthermore, since the route setting processor is configured to set a route while monitoring surplus usage, the connection network can be used efficiently. The route setting processor sets a predetermined coefficient based on the call type and number of calls being transmitted and allocates usage to the quality request value of the call connection requesting side. therefore,
It is possible to use the connection network efficiently while meeting the quality requirements of the call connection requester. In addition, by setting the maximum amount of usage by the route setting processor based on the type of call being transmitted and the cause of the call, there is an effect of absorbing the excess amount of traffic when more traffic than the allocated amount of usage is input.

[Brief explanation of drawings]

FIG. 1 is a relay system diagram showing an embodiment of a packet switch according to the present invention, FIG. 2 is a functional block diagram showing an example of the configuration of a switching module (unit connection w4) in the embodiment shown in FIG. 4A and 4B are diagrams illustrating examples of module link usage tables in the same embodiment. Figures 5A and 5B are diagrams showing an example of a switch link usage table in the same embodiment, Figure 6 is a diagram showing an example of a header correspondence table in the same actual journey example, and Figure 7 is applied to the same embodiment. FIG. 8 is a flowchart showing an example of an algorithm for setting and releasing a route. FIG. 8 is a flowchart showing an example of an algorithm for calculating the surplus usage amount of a route within a connection network applied to the same embodiment. l. ．． ．． 2 4. , ． 5 1 (+. . . 12. . . +4. . . 16. . . 20. . . 22. . . 26. . . 30. . . 32. . . 34. . . 40-47, 50-57 60. H. NOO.Ni. Description of main parts Packet communication network terminal User network interface Switching node Connection network Switching module Node route setting Processor module Link usage table Call processing processor Pinary switch Switch network switch Route setting Processor header correspondence table Switch link usage table Information addition section Adjacent message deletion section Packet switch header input terminal N10.Nj Output terminal P. Bucket RH Routing header

Claims (1)

[Scope of Claims] 1. A plurality of input terminals into which packets are input, a plurality of output terminals which output packets, and a unit connection network connected between the plurality of input and output terminals, with a plurality of stages as constituent elements. of a plurality of possible paths including the unit connection network and the link that transfers a packet input to the connection network to one of the plurality of output terminals; a first route setting means for selecting one of the above unit connection networks; a plurality of input means for adding a routing header to an input packet; a plurality of output means for outputting the packet; a switch network having a plurality of paths connected between a plurality of input means and a plurality of output means and for forwarding an input packet to one of the output means according to its routing header; second route setting means for selecting one of a plurality of routes for each call to which the packet belongs and creating the routing header that is route information; A packet switching device characterized in that it instructs a route setting means to set and release a route. 2. The packet switch according to claim 1, wherein the packet switch has a routing header table for each unit connection network that associates calls with routes of the switch network, and the packet switch constitutes a node of a packet communication network. When a communication route including the switch of the node is set for a call from a terminal of the packet communication network, the first route setting means of each of the switches sends the call to the second route setting means of the switch. and a selected route are recorded in the routing header table, and the record is changed when the call ends. 3. In the packet switching device according to claim 1, when selecting one of the plurality of routes between the unit connection networks, the first route setting means selects a route between the connection networks included in each of the routes. A packet switching system characterized in that the minimum value of the surplus usage of the link is taken as the surplus usage of each of the routes, and the routes are determined in order of the magnitude of the surplus usage. 4. In the packet switch according to claim 3, when calculating the surplus usage of the link, the first route setting means includes the capacity of the call set on the route in the usage capacity of the link. A packet switching device characterized by calculating usage. 5. The packet switch according to claim 1, wherein the packet switch determines the amount of usage of each link between the unit connection networks;
and a link usage table in which the type and number of calls are recorded, and when the first route setting means selects a route connecting the input/output means of the unit connection network, the first route setting means selects a route that connects the input/output means of the unit connection network. Add the usage amount allocated to the call to the usage amount of each link, register the type of call and the number of calls, and when releasing the call, subtract the usage amount from the link usage table and delete the registration. A packet switching device characterized by: 6. In the packet switch according to claim 5, the first route setting means multiplies the requested usage amount from the call connection request source by a coefficient corresponding to the type and number of calls being transmitted. A packet switching device that determines a usage amount to be allocated to the call. 7. The packet switch according to claim 1, wherein the first route setting means sets the maximum usage amount of the link based on the type and number of calls being transmitted.