SWITCHING SYSTEM

Abstract: The invention relates to a switching system composed of switching members, modules and buses, which modules are physical units formed by one or several elements, and are interconnected by means of buses and switching members. The switching members are controllable switches and are arranged in switch groups (S), and they are controlled by means of at least one control unit. In connection with each module (M), there are arranged at least two, advantageously three, switch groups (S1, S2, S3), the first (S1) whereof is connected in between the module (M) and the bus (V), and by intermediation of this switch group the desired linkage channels of the module are connected to the bus which connects the modules to each other. The second switch group (S2) is connected to the bus (V), and thereby the bus channels are divided so that the said first switch groups (S1) and the modules (M) are interconnected via the bus. The possible third switch group (S3) is connected to the linkage channels of the module (M), and thereby the internal switchings of the module are carried out and the desired linkage channels connected to the first switch group (S1).

Description: SWITCHING SYSTEM The present invention relates to a switching system comprising switching members, modules and buses, which modules are physical units formed by one or several elements interconnected by means of buses and switching members. Here a bus means simply a number of exterior channels for connecting the elements to each other. In this connection the term 'element' means processors, storages, linkage gates, channels and other similar members or devices, of the same type and/or of several different types, that can be switched together at least in pairs. The said elements are connected to for instance multiprocessor systems, where they can be interconnected in a wide range of fairly different combinations. The connectable elements can in principle be electric, optical, acoustic etc. in operation. What is in principle required of a versatile multiprocessor computer system is that it should include facilities to form all possible switching combinations in between all of the employed elements. This requirement can be somewhat softened because many of the elements are alike. However, the realization of a versatile switching system in one step is extremely difficult with a large number of elements to be connected. In some of the modern multiprocessor systems, the switching system forms the most extensive and also the most expensive part of the whole system. A switching system can also be realized as a hierarchical system including several switching steps. The object of the present invention is to realize a new switching system based on a hierarchical system. This is achieved by means of the characteristic novel features of the invention which are specified in the appended patent claims. According to the invention, the switching system is composed of switching members, modules and buses, which modules are physical units formed by one or several elements, and are interconnected through buses and switching members. The invention is characterized in that the switching members are controllable switches and that they are arranged in switch groups and controlled by means of at least one control unit, and that in connection with each module there are arranged at least two switch groups, the first whereof is connected in between the module and the bus, and by intermediation thereof the desired linkage channels of the module are connected to the bus, which bus connects the modules to each other, and the second switch group is connected to the bus and thereby the bus channels are divided so that the said first switch groups and modules are interconnected via the bus. Because the module generally contains several separate elements, it is advantageous that in connection with each module there is also arranged a third switch group, which is connected to the linkage channels of the module and whereby internal switchings of the module are carried out by connecting linkage channels to each other, and whereby the desired linkage channels are connected to the first switch group and therethrough to other modules. Among the advantages of the switching system of the present invention, let us mention that the system is easily extended. The number of the switch groups grows as comparable to the number of the processors or corresponding modules. The number of modules can be increased by connecting a new module and required switch groups to the system. The controlling of the switch groups can be carried out either locally or centrally. Moreover, the system is extremely fault-tolerant; damage in some part of one switch element or switch group obstructs neither theOperation of the module nor that of the whole system. According to a preferred embodiment of the invention, the switch groups are formed of switch matrices. The advantage of a switch matrix is that in between its input and output poles, arbitrary switchings can be formed. In addition to this, it is generally 5 supposed that the channels to be switched are duplex, so that the input and output poles are alike and thus interchangeable. In the various embodiments of the invention, different variations of the switch matrices can be used - for instance a switch vector, a triangle 10 switch matrix etc. Moreover, the switch groups, or at least part thereof, can be formed so that their dimension is smaller than the number of the linkage channels in the module. The number of the input and output poles of the switch groups can thus be reduced. "■•• * • According to another advantageous embodiment of the invention, at least two of the said switch groups can be connected to form one common switch group. Such a switch group can be realized for example as a switch matrix, so that the number of required exterior input 0 and output poles can be remarkably decreased. The areas of the common switch matrix can be grouped in a desired fashion. The demand for exterior linkage poles is relatively small, because most of the switchings take place within the switch group. 5 in the following the invention is explained in more detail with reference to the appended drawings, where figure 1 illustrates a module with 16 exterior linkage channels; ° . figure 2A illustrates a switch matrix and its control unit, and figure 2B illustrates the symbol used thereof; figure 3 illustrates a switch vector; figure 4 illustrates a switching system 5 provided with a linear bus; figure 5 illustrates the combining of switch groups Si and S3 into one common switch group; figure 6 illustrates the combining of switch groups SI and S2 into one common switch group; figure 7 illustrates the combining of all of the switch groups into one common switch matrix; figure 8 is a schematical illustration of a combined switch matrix; figure 9 illustrates a switching system with a two-dimensional bus, and figure 10 illustrates another switching system, also with a two-dimensional bus. The switching system of the present invention is based on a hierarchical principle. The elements to be switched are arranged into suitable groups, i.e. physical units, which are below called modules. Figure 1 is a schematical illustration of module M, which contains 16 exterior linkage channels. For the sake of simplicity, let us suppose that the modules are mutually alike and contain an equal number of elements. However, it is pointed out that the modules can differ from each other and/or contain varying numbers of elements. Furthermore, let us suppose that each module contains one or several linkage channels. The channels can be duplex or simplex or both; this is taken into account only in the switch control rules. In practice a channel means for instance a galvanic, optical or other such bus for transmitting information. Moreover, the linkage channels may include one or several physical buses operated on the basis of serial or parallel transmission. Either all or part of the module signals are introduced into the module from outside. In the latter case, a number of permanent switchings has been carried out beforehand inside the module. In the creation of the switchings proper, switch groups are utilized. The switchings are formed at least in between elements located in separate modules, but often also between elements inside one and the same module. By means of the switch groups, there are formed the desired switchings between the input and output channels of the module. The switch groups are composed of a number of controllable switching members, wherethrough signals can be transmitted when the switch is on, and the transmission of signals can be prevented when the switch is off. By means of the control unit, the modes (on/off) of the switching members are set and supervised. One advantageous application of the switch group is a cross-connection matrix, i.e. switch matrix. Figure 2A shows a schematical illustration of a switch matrix, 4 x 4 in dimension, and figure 2B shows the drawing symbol used thereof. Four input poles t are connected, by intermediation of the switching members k, to the output poles 1. The switching members k, t x 1 in number, which are placed at the crossing points of the matrix, are controlled by means of the control unit 0. The blackened triangle in the drawing signifies a switch which is switched on. By means of the switch matrix, the switchings can be formed freely between the input and output poles of the matrix. Moreover, it is generally supposed that the channels to be switched are duplex, so that the input and output poles are alike and thus interchangeable. Naturally switch groups realized in some other fashion can be considered, among others various types of multiphase switches. The control units 0 of the local switch groups can also be switched together in order to provide for global control. The modules to be switched together are connected by means of a bus. It is important that the use of the bus is optimized in between local switchings and switchings with a larger range. This is achieved by controlling the use of the bus by means of a suitable switch group, as is apparent from the description below. Figure 4 illustrates a switching system according to the invention, where the modules M are switched together by means of a linear bus V. There are three switch groups, SI, S2 and S3, per each module M. By means of the switch group SI, there are chosen those channels of the module M wherethrough communication is maintained to the bus V. The switch group S2 is used for commanding the bus, and thereby the bus channels are divided into sections of various lengths according to how far is located the module, either one or several, to be switched to the channel in question. The second switch group S2 is advantageously composed of switch vectors which are schematically illustrated in figure 3. The input poles tl, t2, ..., tn are connected to the output poles 11, 12, ..., In by means of the switches kl, k2, ..., kn. The switches are controlled by the control unit 02. By means of each switch element kl, k2, ..., kn, each of the channels 1, 2, ..., n of the bus V can be switched off at the swich in question. The switch group S3 is employed for carrying out the internal switchings in the module. The third switch group is not necessary in all cases, if the module M is so simple in construction that internal switchings become unnecessary, or if the internal switchings are realized in a permanent fashion. The switch groups SI, S2 and S3 are each provided either with their own control units 01, 02 and 03 (not illustrated in the drawing) respectively, or with a common local control unit. The switch group S3 can be realized as a triangle switch matrix, which is thus devoid of half of the matrix switches and the diagonal elements. This is possible because the switchings are unorganized pairs . The dimension of the switch group S3 can be realized in a smaller scale than the total number of the input and output channels of the module. The dimension of the switch group can be for instance half of the said number. This dimension arrangement is possible if, when allocating the functions for the modules, care is taken of the fact that the connecting channels of the locally switched modules must fall on different sides of the switch group. The functions of the switch groups Si and S3 can be connected. This is carried out by combining the two switch groups to one common switch group. Figure 5 shows how these switch groups are connected to the same switch matrix. The dimension of the switch matrix can be equal to the number of the connecting channels n in the module M. Depending on the application in question, switch groups of other sizes can also be used. Similarly, the ratio between local and global switch groups can be other than the suggested n/2. Instead of a switch vector, the switch group S2 can also be realized as a switch matrix as is illustrated in figure 5. Then, it is true, more switches are needed, but the procedure may be advantageous when combining the functions of the switch groups. The functions of the switch groups SI and S2 can be combined. Thus the said switch groups are combined to one common switch group. Figure 6 is a schematical illustration of how these switch groups are connected to the same switch matrix. The functions of all of the switch groups SI, S2 and S3 can be combined to one and the same switch group. Figure 7 is a schematical illustration of how all of these switch groups are connected to the same switch matrix. In that case the dimension of the switch matrix must be large enough. To realize of all of the switching groups with only one switch matrix is particularly advantageous if there is prepared a switch group specially designed for this purpose. Then the number of the exterior switch poles of the required components can be remarkably reduced. One such switch matrix is illustrated in figure 8. The linkage poles of the module are connected to the poles ml of the switch matrix, the bus V is connected to the input poles vs of the bus, and to the output poles vu of the bus. The switch matrix is divided into se ' ctions where the local switchings are carried out in the area 1, the global choice of channels in the area 2, and the extension or separation of the bus channels in the area 3. The said switch matrix must be realized as a so-called generalized structure: it is legal to activate several switch members in the same row or column. In figure 8, the sections 1, 2 and 3 of the switch matrix can be chosen to be suitable in size to the particular application. These sections of the matrix can be grouped in various different ways, only one possibility of which is presented in the said drawing. A more complete combined matrix is illustrated in figure 7, where the global signal can be chosen from both of the bus connectors. It is particularly pointed out that the combined matrix switchings do not have to be complete, i.e. it is not absolutely necessary to have a switch at each crossing point, but, depending on the application in question, the switches can be placed in a triangle matrix or even in a diagonal only. A remarkable advantage of the combined switch group is that the number of required exterior channel connectors is relatively low, because most of the switchings can be carried out within the switch matrix. In the above specification, the switching system of the present invention is illustrated with reference to a linear bus. One example of how the switching system is applied to a two-dimensional bus is illustrated in figure 9. The switch groups S connected to the modules M, which for the sake of simplicity are presented as one single block, perform the switching and isolation of the channels in between the modules with respect to the buses Via, V16 and V2a, V2b, V2c with both X and Y directions. Figure 10 illustrates how the switching system of the invention is modified to fit in another two- dimensional bus. At the crossing points of the buses Via, Vlb and V2a, V2b there are placed separate switch groups S2. By means of the switch group S2, at each channel there can be carried out any of the following procedures: the channel can be directly connected in the direction of the X or the Y coordinate, the channel can be turned from direction X to direction Y or vice versa, or the channel can be cut off. In addition to this, the modules M chosen on the basis of the switch group SI can be connected, through desired linkage channels, to the bus VI. The switch groups Si, S2 can be realized in similar fashion as in the case of a linear bus: by means of matrix, vector or multistage switches, and/or combinations thereof. Various irregular switch types can also be considered. A particularly practical solution in this case, too, is to apply the combined switch matrix of figure 7 or 8, for instance. The switching system of the present invention can be analogically applied to switching three- dimensional modules and/or to be used in connection with three-dimensional bus structures. Switchings with even more dimensions are also possible, but this does not bring about any additional advantages as for the physical realization of for instance multiprocessors. It is pointed out that although the invention is above described with reference to a few preferred embodiments, it is naturally clear that the invention is not limited to them exclusively. The invention can be applied to many different types of switching systems, within the scope of the inventional idea determined in the appended patent claims.

Claims: PATENT CLAIMS ,_, A switching system composed of switching members, modules and buses, which modules are physical units formed by one or several elements, and are interconnected by means of buses and switching members, c h a r a c t e r i z e d in that the switching members are controllable switches (k) which are arranged in switch groups (S) and are controlled by means of at least one control unit (0); that in connection with each module (M), there is arranged at least two switch groups (SI, S2), the first (Si) whereof is connected in between the module (M) and the bus (V), and that by intermediation of the first switch group (SI), the desired linkage channels of the module are connected to the bus, which connects the separate modules to each other, and that the second switch group (S2) is connected to the bus (V) and thereby the bus channels are divided so that the said first switch groups (SI) and modules (M) are switched to each other via the bus. 2. The system of claim 1, - c h a r a c t e ¬ r i z e d in that in connection with each module (M), there is arranged a third switch group (S3), which is connected to the linkage channels of the module and whereby internal switchings of the module are carried out by connecting linkage channels, and the desired linkage channels are connected to the first switch group (Si) and therethrough to other modules. 3. The system of claim 1 or 2, c h a r a c - t e r i z e d in that the switch groups (Si, S2, S3) are formed of switch matrices. 4. The system of claim 3, c h a r a c t e ¬ r i z e d in that the second switch group (S2) is formed of switch vectors. 5. The system of claim 1, 2, 3 or 4, c h a ¬ r a c t e r i z e d in that the third switch group (S3) is composed so that its dimension is smaller than the number of the linkage channels of the module (M) . 6. The system of claim 1, 2, 3 or 4, c h a ¬ r a c t e r i z e d in that the third switch group (S3) is formed of a triangle switch matrix. 7. The system of any of the preceding claims, c h a r a c t e r i z e d in that at least two of the said switch groups (SI, S2; Si, S3; Si, S2, S3) are combined to form one switch group in common.

Inventors: LEPPAELAE KARI PAAVO ANTERO, LEPPAELAE, KARI, PAAVO, ANTERO
Applicants: VALTION TEKNILLINEN, VALTION TEKNILLINEN TUTKIMUSKESKUS
Application year: 1989
Main classification: G06F15
IPC codes: G06F13, G06F15, H04L12