JPH02268536A - Switching device and packet switching machine having the same - Google Patents

Abstract

PURPOSE:To attain the simplification of a binary switch comprising a switching device and to prevent the time sequence of a packet that belongs to the same call from being reversed within a switch by setting a single route at every information to be switched, for example, in call unit. CONSTITUTION:A route information attaching means 12 to receive the information and to attach route information routing in a switch network 10 on the information, and a header correspondence means 16 in which the route information is stored corresponding to an identification number included in inputted information are provided. Also, a link working status means 20 in which the working status of each link of the binary switch in the switch network 10 is stored, and a route setting control means 18 which performs the route setting of the information in the switch network 10 by input/output information are provided. Thereby, the constitution of the binary switch can be simplified, and the switching device in which no reversal of the time sequence of the packet that belongs to the same call occurs and a packet switching machine having the same device can be realized.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a switch device, and more particularly, to a switch device that is advantageously applied to communication equipment that performs switching processing, such as a packet switch.

(Prior Art) As the information society progresses, communication networks that transmit information are required to have higher speeds and larger capacities so that they can support multimedia. For example, in packet switching equipment used as a node in such a communication network, improving the usage efficiency of the switching device that performs switching processing has become an important issue.

As is well known, some switching networks of switching devices formed as switching networks of packet switching equipment have a configuration in which two binary switches each powered by two outputs are connected in multiple stages. In a switch network of such exchanges, it is also possible to have a configuration in which a plurality of routes exist connecting arbitrary inputs and outputs. Therefore, the switching equipment needs to perform connection processing to set the optimal route for input packets from among a plurality of routes, taking into account the usage efficiency of the entire switch network.

As a multi-stage connection network of binary switches in which there are multiple paths connecting arbitrary inputs and outputs, a Benes network is said to be capable of a switch configuration with the minimum number of binary switches. For example, Kishimoto and Sakurai, "Configuration of multi-stage switching circuit using dynamic load distribution control" IEICE technical report 5E87-
61, pp. 65-70, describes a conventional technique for load distribution using a Benes network. In this conventional technology,
The binary switches in the sorting section (distributed network) of the Benes network perform load distribution by setting routes based on the loads of the binary switches on their output side, thereby improving the usage efficiency of the entire switch network.

(Problems to be Solved by the Invention) However, in such a conventional technique, each binary switch monitors its own load, resulting in a complicated and large hardware structure. Furthermore, since packets input to the switch are processed packet by packet, the time order of packets belonging to the same call may be reversed after passing through the switch. Therefore, it was also necessary to restore calls whose time order was reversed.

It is an object of the present invention to overcome the drawbacks of the prior art, to provide a switch device that has a simple binary switch configuration, and that does not cause the reversal of the time order of packets belonging to the same call, and a packet switch having the same. shall be.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has a plurality of paths connecting an input side where information for performing switching is inputted and an output side where this information is outputted. A switching device including a switch network connected in multiple stages by binary switches is
A route information adding means receives the information and adds route information for routing within the switch network to this information, and the route information added by the route information adding means is stored in correspondence with the identification number included in the input information. a link usage status means that stores the usage status of each link of the binary switch in the switch network, and a link usage status means that receives input/output information on the input side where information is input and the output side where information is output. , and a route setting control means for setting information routes in the switch network based on input/output information6.Furthermore, according to the present invention, a packet switch including a plurality of switch networks in which a plurality of call switching routes exist, a route information adding means for adding route information for routing within the network to a call; and a header corresponding means in which the route information added by the route information adding means is stored in correspondence with an identification number included in the call; The link usage status means stores the usage status of each link in the switch network, and the route of the call in the switch network is set by referring to the link usage status means, and the set route is stored as route information in the header corresponding means. When setting a call connection, the route setting control means selects a switch network suitable for the call from among the switch devices, and outputs the call to the input terminal of the switch device into which the call is input to the route setting means of the switch device. and call processing control means for instructing the output terminal of the switching device to perform the call processing.

(Function) According to the present invention, when setting up a connection before information is input to a switch network, input/output information of this information, that is, from which input terminal of the switch network is this information input and to which output terminal is it output? information on whether to do so is sent to the route setting means.

When the route setting means receives this input/output information, it calculates all routes that can be set in the switch network, and by referring to the link usage status means, selects the optimal route with the maximum usage margin from among the calculated routes. Select.

Then, this optimal route is stored in the header correspondence means. The route information adding means receives the information.

The optimal route corresponding to this information is read from the header correspondence means, and route information, which is this route information, is added to the information. Thereby, information is routed through each binary switch in the switch network according to the route information, and is output to the output terminal specified by the input/output information.

(Embodiment) Next, an embodiment in which a switch device according to the present invention is applied to a packet switch will be described in detail with reference to the accompanying drawings.

FIG. 1 shows a functional block diagram of a switch device in a packet switch as an embodiment of the present invention. The switch device l in this embodiment includes a Benes switch network IO,
The basic configuration includes a route information addition section 12, a route information deletion section 14, a header correspondence section 16, a link usage status section 20, and a route setting control section 18 which is a specific processor of the switching device l that controls and manages these.

The switch network IO is a switch network such as a Benes network for exchanging input packets 100 having information 102 and headers 104, and has 2×2 binary switches 30 connected in multiple stages. In the figure, the Benes switch network IO is an 8×8 Benes network in which binary switches 30 are connected in five stages from the 0th stage to the 4th stage.
An N-Benes net may also be used.

Further, any switch network may be used as long as it is an NXN binary switch multi-stage connection network that has a plurality of paths connecting arbitrary inputs and outputs.

A route information addition unit 12 is connected to each input line of the zero-stage binary switch 30-0 for each input line. The input side of the route information addition section 12 is connected to the input port #i (where i=0 to 7) of the switching device I and to the header correspondence section 16, respectively. The information adding unit 12 adds, to the packet 100 input from the input boat,
This is an information adding section that adds route information 114 for routing within the switch network 10.

For example, header 104 of packet 100 includes a logical channel number (FIG. 6). The route information addition unit 12 reads route information 114 corresponding to the logical channel number of the input packet 100 from the header correspondence unit 16 and adds it to the header 104. After adding route information 114, the route information adding unit 12 sends the packet 100 to the 0th stage binary switch 30-0. Note that the same logical channel number is added to packets 100 belonging to the same call. Therefore, in this embodiment, packets 100 belonging to the same call are switched through the same route and output to output port #j (where j=0 to 7).

Therefore, the time order of packets is never reversed.

A route information deletion section 14 is connected to the output side of each of the last-stage binary switches 30, that is, the fourth-stage binary switches 30-4 in the figure, for each output line. The route information deletion unit 14 deletes the input packet 1
This is an information deletion unit that deletes the route information 114 added by the route information addition unit 12 from the ladder 104 to the zero cell.

The header correspondence unit 16 is a storage unit that stores the correspondence between the logical channel number of the call included in the input packet 100 and the route information 114 that is self-routing information thereof. FIG. 6 shows an example of the header correspondence table stored here. As shown in the figure, for example, packet ioo with logical channel number rQJ has rll
The route information 114 of oll J is added. The binary switch 30 at each stage uses the manual packet 100 by referring to one bit at a predetermined position in the route information 114.
Switching. Note that the route information 114 shown in the figure is 5 bits, but this is because in the case of an 8×8 Benes network, the binary switch 30 has a 5-stage configuration. Therefore, in the case of the NXN Benes network, the route information 114 requires 21ogJ-1 bits.

Returning to FIG. 1, the link usage status unit 20 is a link usage status storage unit that stores a link usage status table that registers the link usage of the switch network IO and the type and number of calls being transmitted. The link usage status table has data regarding the usage of all links between the binary switches 30 and the type and number of calls being transmitted.The link usage is the total transmission capacity that has already been set. In addition, calls being transmitted over a link are divided into several types, or call types, according to required quality declared values (bursty, average transmission capacity, allowable delay time, allowable packet loss, etc.), and which types of calls are classified into different types. Register how many there are.

To change the data, as will be described later, when setting up a call, the transmission capacity allocated by the route setting control unit 18 is added to all links belonging to the set route, and the call type is registered at the same time. Furthermore, when releasing a call, the transmission capacity allocated by the route setting control unit 18 to the call to be released is subtracted from all links belonging to the set communication path, and at the same time, the call type is excluded from registration.

Figure 4 shows link usage status table 4 in the NXN Benes network.
00 is shown. The link usage status table 400 determines the position of a certain link based on what stage (fn) it is in and what boat (ml) it comes from, and shows the amount of link usage and the link being transmitted as data. Information [X (m, nl)] including the call type and number of calls is stored.

Note that the call types are classified according to the statistical characteristics of the call, as described above. The developed diagram 410 shown here is the link X f which is the 21ogJ-3rd stage and the N-1st
This shows an example of registration of the usage status of N-1, 21ogJ-3). For example, link usage status section 20 like this
For each link, the usage amount C and the call type and number of calls being transmitted through this link are stored.

Returning to FIG. 1, the route setting control unit 18 is connected to the header correspondence unit 16 and the link usage status unit 20, and to a call processing control unit 50 which is a call processing processor of the packet exchange. The route setting control unit 18 is a processor that sets a routing bus for the packet 100 input to the switch network IO.

That is, when the route setting control unit 18 receives a call connection instruction from the call processing control unit 50, the route setting control unit 18 connects the switch network I based on this instruction.
O selects the optimal route for efficient switching processing.

The call processing controller 50 is connected to a plurality of route setting controllers 18 via a control signal line 150.The call processing controller 50 is also connected to a plurality of terminals 60 via an outband signal line 152.
It is connected to the. The call processing control unit 50 determines whether the connected switching device l
It is determined which input port #i of the switch network IO should be connected to which output port #j. Then, a control signal 150 including information on the input port #i and the output port #j is sent to the path setting control unit 18 of the corresponding switch device 1. The call processing control unit 50 also knows which path of the switch network IO should be released.

The terminal 60 is a terminal device such as a communication device or an information device housed in a packet exchange including the switch device l. Note that although the call processing control unit 50 is depicted as receiving an outband signal from one terminal 60 in the same figure, this is to avoid complicating the diagram; outband signal 152 from the terminal 60 of
receive.

The terminal 60 requests the call processing control unit 50 to connect a call by transmitting an out-of-band signal 152. This signal 152 includes, for example, the originating address of the calling terminal 60;
It includes the destination address and required quality declaration values (bursty, average transmission capacity, allowable delay time, allowable packet loss rate, etc.). The call processing control unit 50 controls the terminal 60
Upon receiving the connection request outband signal 152 from
Determine which input/output port of the switch should be connected from the outgoing address and incoming address. Then, it instructs the route setting control section 18 of the corresponding switch device 1 which human output boat should be connected.

Upon receiving the instruction, the route setting control unit 18 receives the information on the input port #i and the output port #j and determines whether or not the route setting between them is possible. Then, if the route can be set, access the header correspondence section 16 and change the correspondence table between the logical channel number of the call and the route information, and at the same time,
Change the link usage status in the link usage status section 20.

When the route information addition section 12 receives the packet 100, it reads out the route information 114 corresponding to the logical channel number indicated in the header 104 from the header correspondence section 16. Then, the corresponding route information 114 is added to the header 104 of the 10 input packets and sent to the Benes switch network IO. The packet 100 is routed within the switch network IO based on the route information 114 and
The route information 114 is sent to the route information deletion unit 14 disposed on the output side of the route information 114, where the route information 114 is deleted.

Packets 100 belonging to the same call have the same logical channel number added to them. Therefore, the same route information 114 is added to the packet 100, and the packet 100 is routed along the same route in the network IO. As a result, in this embodiment, the time order of packets belonging to the same call is not reversed within the switch.

Next, route setting processing in this embodiment will be explained.

Route setting is basically executed by determining the route with the most margin for usage based on the amount of link usage between the binary switches 30. For this reason, the route setting control unit 18
The amount of usage of all links in the switch network IO and the type of call being transmitted
A link usage table 400 in which the number of calls is registered can be accessed.

FIG. 2 shows the basic process of route setting in this embodiment. Using the same diagram, connect the switch network L in Figure 1 to NX.
The operation when an N Benes switch network is used will be explained. The route setting control unit 18 receives the control signal 15 from the call processing control unit 50.
0 is received, it is determined whether this signal 150 is an instruction for setting up a call or releasing a call.
-1) and the output boat #, Nj·0 to N-1), there are 2*(logJ-1) routes. Therefore, in the case of setting up a call, the following processes 206 and 2 are performed.
Connect 08 to input boat #i and output boat #j 2**
First, the number of repetitions k is initialized to "0" so that the number of routes S, which is flogzN-11, is executed (202). After initialization, all these routes are restored in the form of route information 114 (204).

In this way, after extracting all routes connecting input boat #i and output boat #j, the surplus usage of each link belonging to one of the possible routes is calculated +2061
゜Then, the minimum value of the margin usage of each link determined in process 206 is calculated, and this value is set as the route margin usage +208+. As mentioned above, these processes are performed the total number of routes S times, so when the process 208 is finished, the number of repetitions k is incremented by lJ [2101, and by comparing the number of repetitions and the total number of routes S, the set It is determined whether the calculation process for the number of possible routes has been executed (212)
.

If this calculation process has not been completed, that is, if k<s, the process returns to process 206. Furthermore, if k≧S and execution has been completed for the number of settable routes, one route with the maximum usage margin is selected (214). Note that, at this time, if there are multiple routes with the same usage margin, one of them is selected at random. Additionally, if the spare transmission capacity of the selected route is smaller than the allocated transmission capacity for the call to be set up, the call cannot be transmitted even if this route is set up. By comparing the allocated transmission capacity for the call, it is determined whether the route can be set+2161.

When the route setting control unit 18 determines that route setting is impossible, it reports this to the call processing control unit 50 (2201);
The process ends. Further, when determining that route setting is possible, the route setting control unit 18 changes the header correspondence table and link usage status table 400 to +2081.
, and notifies the call processing control unit 50 (2201) to end the process.

Further, when there is an instruction to release the call from the call processing control unit 50,
The route setting control unit 18 changes the header correspondence table and the link usage table 400 (218) and notifies the call processing control unit 50 to that effect, as in the case where the route setting is possible.
201, the process ends.

FIG. 3 shows the detailed contents of the process 204, that is, a specific example of the process of extracting route information of all routes connecting input boat #i and output boat #j. As described above, the number of bits of the route information 114 necessary for self-routing is equal to the number of stages of multi-stage connection, and is f21ogJ-11 bits in the case of an NxN Benes network. this house,
Since the lower 1ogzN bits (3 bits in the 8x8 Benes network) are the 2-bit representation of the output port #j, we obtain the 2-bit representation of the output port #j and use this as Hb.
00).

Next, the upper (10gJ-11 bits (2 bits in 8x8 Benes network) is all the combinations represented by (logJ-11 bits), so all the combinations represented by logtN-11 bits. Find this set as °
(Hfl [3021°) Then, add each element of (Hf) in front of Hb, 2*umbrella(logJ~1
) route information 11 (4 ways in 8×8 Benes network)
4 and saves it in the memory (not shown) of the route setting control unit 18 (3041, hereinafter referred to as the route information 114).
is expressed as +ho, , , ura f21ogzN-211.

The route allowance usage amount determining process related to the processes 206 and 208 will be described with reference to FIG. Route setting control section 1
8 reads one of the headers (hO, . . . ura 121ogJ-2) l, which is the route information of the route for which the usage margin is to be known (50 entries). Next, the header (h
o, , , Link usage amount C that has already been allocated as a route belonging to the route determined by Ura f21ogJ-211
f0) to C(2], ogzN-3) are read from the link usage status section 20 (502).

The route setting control unit 18 also reads the read headers tho,
, , Ura f21ogJ-2)))), the allocated usage amount V(0) ~
V f21ogJ-3) and the maximum usage amount M of that link
Calculate (0) ~ M (21 gJ-3) (5041
゜Next, the surplus usage amount Pf[,) of the target link is
Use fit CfLl, V (L) i3 and M (L
) using the following formula to calculate f5061.

PfL)=M(Ll-(CfL)+VfL)l
(5-11 (however, L is an integer from 0 to 21ogzN-3)
The route setting control unit 18 calculates the calculated link allowance usage amount P.
The minimum value of fLl is &4IN, and this minimum value MIN is taken as the route's spare usage (508).In other words, the surplus usage of the link that is the most bottleneck on the route for which you want to know the surplus usage is taken as the representative value. It is.

Read route information fhO,,,,,hf21ogJ
-2)) and the minimum usage amount P fL) of this
0 or more processes stored in the memory of the route setting control unit 18, that is, processes 500 to 510, correspond to process 2 in FIG.
This is executed for all routes that can connect input boat #i and output boat #j extracted in step 04.

Note that the transmission capacity V (Ll), that is, the allocated usage amount V (Ll) of the call to be routed, is the value obtained by multiplying the requested transmission capacity cd issued by the call setup requesting side by a coefficient A. It is determined by how many call types are being transmitted on the link.The more statistical multiplexing effect can be expected, the more
Coefficient A becomes smaller. Therefore, the allocation use ff1Vf
L) has different values depending on the link.

In addition, the maximum usage amount M (Ll) of the link of interest is determined by how many call types are transmitted through that link. The more statistical multiplexing effect can be expected, the larger the coefficient M (Ll) becomes. , the usage amount M(L) also has different values depending on the link.When more traffic than the usage amount allocated by setting the usage amount M(Ll) is input, the effect of absorbing the excess amount can be expected.

Note that the route setting process used in this embodiment is applicable not only to route setting within a switch, but also to route setting within a communication node or in information processing, or route setting within a network (flow control). For this reason, one embodiment of the present invention may be used, for example, in an ATM (Asynchronous Transmitter).
It may equally be applied to switching devices such as fer model switches or parallel computers.

(Effects of the Invention) According to the present invention, since a single path is set for each switching information, for example, a call, it is possible to simplify the binary switch that constitutes the switching device, and also to The time order of packets is never reversed within the switch. Furthermore, since connection processing is executed by a control unit specific to the switch, it is possible to distribute the load required for route setting processing.

In addition, the route setting process based on link surplus usage estimation allows it to be applied to any binary switch multi-stage connection type switch that has multiple routes connecting arbitrary inputs and outputs, making it highly versatile. Moreover, this route setting process can simplify the hardware configuration for monitoring link usage.

Furthermore, since the route setting control unit sets the route while monitoring the usage allowance, the switch network can be used efficiently. Furthermore, the route setting control unit allocates transmission capacity by setting a coefficient A based on the call type and number of calls being transmitted to the quality request value of the call connection requesting side. , it becomes possible to use an efficient switch network. Also,
By setting the maximum usage amount based on the type of call and the number of calls being transmitted by the route control unit, even when more traffic than the allocated usage amount is input, the effect of absorbing the excess traffic can be expected.

[Brief explanation of drawings]

1 is a functional block diagram illustrating an embodiment of the switch device according to the present invention applied to a packet switch; FIG. 2 is a flow diagram illustrating an example of route setting processing in the switch device of FIG. 1; 2 is a flowchart showing a detailed example of route information extraction processing for all routes in FIG. 2, FIG. 4 is an explanatory diagram showing an example of link usage status in this embodiment, and FIG. FIG. 6 is a flowchart showing a detailed example of the surplus usage amount calculation process. FIG. 6 is an explanatory diagram showing an example of header correspondence in this embodiment. main . Description of ``Switch device Benes switch network Route information addition section Route information deletion section Header correspondence section Route setting control section Link usage status section Binary switch Call processing control section Terminal packet

Claims (1)

[Scope of Claims] 1. In a switching device including a switch network connected in multiple stages by binary switches, in which there are a plurality of paths connecting an input side where information for switching is inputted and an output side where the information is outputted, The switch device includes: a route information adding unit that receives the information and adds route information for routing within the switch network to the information; and a route information added by the route information adding unit that is included in the input information. a header corresponding means stored in correspondence with the identification number of the binary switch; a link usage status means storing the usage status of each link of the binary switch in the switch network; and an input side into which the information is input. A switching device comprising a route setting control means for receiving input/output information from an output side that outputs the information, and setting a route for the information in the switch network based on the input/output information. 2. In the switching device according to claim 1, when setting a route for the information, the route setting control means refers to the link usage status means to determine the surplus usage of all routes for which the information can be set. Obtained assuming that the route is set,
The method is characterized in that the determined minimum value of the surplus usage of links in each route is taken as a representative value of each route, and the route having the maximum representative value is stored in the header correspondence means as route information of the information. Switch device. 3. In the switching device according to claim 1, when the route of the information is set, the route setting control means adds the transmission capacity allocated to the information to all links belonging to the set route of the link usage status means. At the same time, the type and number are registered, and when the information is released, the transmission capacity allocated to the information is subtracted from all links belonging to the release route of the link usage status means, and at the same time, the type and number are registered. A switch device characterized by being excluded from registration. 4. In the switching device according to claim 1, when setting a route for the information, the route setting control means sets the transmission capacity allocated to the information to the requested transmission capacity received from the connection request source of the information. A switch device characterized in that the determination is made by multiplying by a predetermined coefficient set based on the type and number of information contained therein. 5. In a packet switch including a plurality of switch devices in which a plurality of call switching paths exist, the switch includes: route information adding means for adding route information for routing within the switch device to the call; and the route information. a header correspondence means in which the route information added by the addition means is stored in correspondence with an identification number included in the call; a link usage status means in which the usage status of each link in the switching device is stored; and a route setting control means for setting a route of the call in the switching device with reference to the link using means, and storing the set route in the header corresponding means as the route information, and setting a connection for the call. At this time, a switch device suitable for the call is selected from the switch devices, and the input terminal of the switch device to which the call is input and the output terminal of the switch device to output the call are connected to the route setting means of the switch device. 1. A packet switch comprising: call processing control means for instructing terminals.