SE504347C2 - Procedure and system for dynamic resource allocation in a telecommunications network - Google Patents

Abstract

A method of dynamic resource allocation in a stratified network structure comprising a dynamically switched first stratum network (1) and at least a second stratum network (2, 3) underlying said first overlying stratum network. In accordance with the invention, at least a first route in the first stratum is provided with a first relation (50, 51; 87, 88) which points out two access points (A1, A2; A5, A6) in the second stratum. A connection (A-23-A2 or A1-25-24-A2 or A5-36-35-34-A6) between said access points in said second stratum network (2) is established and comprises a second number of resources generally referred to as an infrastructure. The infrastructure is finally assigned to said first route (13).

Description

15 20 25 30 35 504 347 2 Two oppositely directed channels running between the same pair of points are hereinafter referred to as a pair of channels. Several channel pairs together form a link. A link is a physical system (which transports information). Thus, a link carries channel pairs. The maximum number of channel pairs a link can carry depends on the carrier service and on the characteristics of the physical system.

A 'road is a logical concept. A * path consists of a number of channel pairs and is used to connect two nodes to each other.

Theoretically, a road can have as many channel pairs as it wants.

The term path is used to define the physical path along which a connection runs between two nodes in a stratum. This physical path is known as a road or route.

At each end of a link there is a selector terminal ET (exchange terminal). An ET works by "pushing in" or multiplexing together a number of channel pairs on one and the same link, and it also works by "extracting" or demultiplexing channel pairs from the same link.

The above definitions are explained in connection with Figs. 1 and 2. Fig. 1 shows a path R1 extending between two nodes N1 and N2. As an example, the road R1 is assumed to carry 96 channels so distributed that there are 48 channels ~ in each of the two opposite directions, i.e. road R1 carries 48 channel pairs. Fig. 1 is a logical description of the physical transmission system in Fig. 2. In Fig. 2 there are two links L1 and L2 which go between the nodes N1 and N2.

At each end of the links L1 and L2 there is each selector term ET. Assume that the carrier service is STM 64, then the link L1 will carry 64 channels distributed so that there are 32 channels in each of the two opposite directions. Thus, the link L1 carries 32 channel pairs. In the same way, the link L12 carries 32 channel pairs. All 32 channel pairs in the link L1 but only 16 channel pairs in the link L2 are so grouped that they form the path R1, which will thus contain 48 channel pairs. In the physical transmission system of Fig. 2, the remaining channel pairs, not used in the path R1, may form part of another path, not shown in Fig. 1, in the link 10. In Fig. 2, the nodes N1 and N2 correspond to the nodes N1 and N2 in Fig. 1.

Fig. 3 shows three strata 1, 2 and 3. Each stratum represents a logical view of a physical transport network (not shown). Stratum 1 has three nodes 10-12, stratum 2 three nodes 20-22 and stratum 3 four nodes 30-33. Stratum 1 has three paths 13-15, stratum 2 three paths 23-25 and stratum 3 three paths 34-36. As an example, the carrier service in stratum 1 is 64 kbps STM (synchronous transmission mode). As an example, the carrier service in stratum 2 is 2 Mbps STM (in the US 1.5 Mbps STM). As an example, the carrier service in stratum is 3,155 Mbps STM. As an example, paths 13, 14, 15, 25 and 34 are shown to contain two link channel pairs while paths 23, 24, 35 and 36 are shown to contain channel pairs to only one link. A link is marked with a solid line. The links in path 13 are designated 40 and 41. Each stratum has access points to different networks.

These access points are shown schematically with filled points on each stratum. Each access point has a connection to a node in resp. stratum. In stratunn 1, the connections from the access points to node 10 are collectively denoted by 16, from the access points to node 11 are collectively denoted 17 and those to node 12 by 18. stratum 2. Similar connections 37, 38 are also found in stratum 3. while the connections Similar connections 26 and 27 are in Access points are connected to access points. The access units are used for communication. As an example of access units, stratum 1 shows two telephones A and B. Access units also appear in stratum 2 and are shown symbolically at C and D, respectively. Examples of access units in stratum 2 are mainframes. In stratum 3, the access units are symbolically denoted by E resp. F. In the not shown.physical 17, 18, 26, 27, 28, 37 and 38 at its node side connected to its resp. node with the transport network is each of the connections 16, by means of a selector terminal ET. Seen from the perspective of the transport network, such 'select terminals * are.conventional line interfaces- so-called LIC circuits, circuits, in case the carrier services are STM 64 Mbps. l 15 15 25 25 30 35 504 347 4 A selector terminal ET in a stratum is shown in the drawings as an unfilled square.

Nodes 10-12 in stratum 1 usually comprise so-called voter structures. A selector in the physical transport network corresponds to one or more selector structures in different strata. Cross-connectors in the physical transport network would correspond to nodes 20-22 in stratum 2. Wire connections in the physical transport network would correspond to nodes 30-33 in stratum 3.

Stratum 1 forms a connected network in the sense that it is possible to route a connection from an originating access unit to a terminating access unit by dialing the telephone number of the terminating access unit at the originating access unit. Stratum 2 is usually an unconnected network.

A connection from C to D is usually a fixed leased line set up by a network operator and the fixed line connection is set up for a long time. Stratum 3 is an unconnected network.

In stratum 1, each path 13, 14, 15 represents a number of resources between two nodes, which resources exist in the form of channel pairs.

Nodes 10, 20 and 30 may, but need not, correspond to each other depending on the structure of the physical transport network. In general, they do not correspond to each other because their physical counterparts in the physical transport network are located in geographically different places. Nodes 10, 20 and 30 would correspond to each other if the selector, the cross-coupler and the wire connection were all located in the same geographical location. The same applies to nodes 11, 21, 31 and to nodes 12, 22, 32.

The units described above together form a traffic system. The traffic in each stratum varies depending on the time of day, the current day of the week and may also depend on other conditions.

As an example, a head office of a company that has sales offices in many different cities may want the sales offices to report back to the head office all during a 10 15 20 25 30 35 504 347 5 day sold units. This information should be sent to headquarters at night. The time it takes to perform such a data transfer may be unacceptably long if the transfer takes place using the carrier service provided in stratum 1.

This is because of the limited bandwidth offered by the 64-kbps STM network. Instead, the company has leased a number of 2-Mbps connections that connect the sales offices with the head office. These 2-Mbps connections are set up in stratum 2 by a network operator in this stratum 2. This setup is done manually by the network operator using an operation and maintenance system, DoU, 29. The leased 2-Mbps connections in stratum 2 are set up night time between e.g. at 8.00 in the evening and 5.00 in the morning.

During the day, the hydrated connections in stratum 2 are used for other traffic. In this way, at a predetermined time, the network operator reconfigures the resources contained in stratum 2 in order to use its resources as efficiently as possible. The operation and maintenance system 29 controls and monitors the operation of the nodes and paths in stratum 2. There is also a DoU 39 for controlling and monitoring corresponding units in stratum 3.

Manual erection of connections in stratum 2 at predetermined times is a rigid way of meeting users' traffic requirements. Users must make the network operator aware of their requirements and the network operator must set up the connections manually. Should a user happen to need access to a leased line at any time other than that agreed with the network operator, the user must contact the network operator. The network operator must then examine the current traffic situation in stratum 2, assign the customer a link and manually set up the connection 'for a fixed period of time. The time gap between the order and the establishment of the connection can be in the order of days.

Because the connections in stratun12 are leased during fixed time periods and because the traffic demand can vary during these fixed time periods, the network resources in the physical network are not used efficiently. 10 15 20 25 30 35 504 347 CLOSELY RELATED ART U.S. Patents 5,058,105, 5,182,744 and 5,031,211 relate to methods and devices for improving the reliability of a communication network so that interrupted traffic, e.g. due to an incorrect link, quickly restored. Various methods are described for determining alternative routes over which the interrupted traffic is routed.

U.S. Pat. No. 4,669,113 relates to a non-hierarchical switching system: utilizes an algorithm for developing link sizes for paths which connect selectors to each other in the switching system. This is achieved by sending each selector in the switching system information about free trunks to a centrally integrated network controller on a periodic basis, e.g. every five seconds, when trunk status changes occur, ie. vacant trunks are created or removed. Based on the received traffic information, the integrated network controller determines the required number of trunks per link using a process that adapts to the traffic management capacity between nodes based on the availability of alternative routes.

EP-A2-464 283 relates to the allocation of a limited, common resource, such as e.g. trunks for video conferencing, among several clients of the resource. An assignment method is described, which makes it possible to allocate bandwidth of a communication path in the network among a number of customer requirements that desire this bandwidth. Examples of client requirements for a conference are start time, stop time, maximum bandwidth and minimum bandwidth. Each conference reservation is associated with "binding" consisting of a quadruple of the form (X1, X2, X3, X4) where X1 and. X2 refers to specific positions in the bandwidth of the communication path and X3 and X4 refer to the start time respectively. the closing time of the conference. A customer place represents one or more endpoints. An assignment procedure receives orders from an ordering location and assigns networks for communication between a plurality of stratified customer locations. The award procedure received orders soul response- on a. grouping 'of' the 10 15 20 25 30 35 504 347 7 endpoints to be in conference with each other and then allocating network resources in response to the stratified need.

Thus, the allocation process takes place at predetermined times in accordance with a customer's needs and is not driven by the prevailing traffic load.

BRIEF DESCRIPTION OF THE INVENTION An object of the present invention is to provide a method and system for providing a connection along a road in a higher stratum by utilizing dynamic allocation of an infrastructure in a lower stratum in a stratified network structure with the avoidance of the disadvantages of the prior art.

More specifically, the allocation of an infrastructure in a lower stratum shall be demand-driven and take place in response to the prevailing traffic situation along a road in the said higher stratum.

In accordance with yet another aspect of the present invention, the allocation of a lower stratum infrastructure to a higher stratum is controlled from within the traffic system. Thus, there is no system external operation and involved in the allocation process and maintenance system, no operator needs to be contacted when the allocation is to be made. The allocation can therefore take place dynamically and be demand-driven.

In accordance with another aspect of the invention, assignment processes allow repeated assignments of infrastructures from a number of underlying strata to an overlying stratum.

The above objects are achieved by providing a road with a first reference associated with one endpoint of the road and a second reference associated with the opposite endpoint of the road. The first reference refers to a first access point located in a lower stratum. The second reference refers to a second access point located in said lower stratum. From the node at said one end of said path, a wire connection is arranged to the first access point in said lower stratum.

Likewise, from the node at the opposite end point of said path, a similar wire connection is provided to the second access point located in said lower stratum.

When control logic requests the establishment of a connection in a first stratum, the connection typically runs along a number of paths. Assume that the traffic load along one of these roads is so strong that all the resources of the said one road are occupied. Traditionally, a connection order made in such circumstances is rejected. In accordance with the present invention, the control logic first examines the said one path to see if any of the mentioned references are associated with the path. If the path is not associated with any such references then the connection order is rejected but if the path is associated with such references then the control logic takes the references and sends them, in a second connection order, to the stratum associated with the access points. The second connection order requests the establishment of a connection between the two access points with which the references are associated. Typically, these access points are in a stratum, called the second stratum, located closest to the one in which the busy road is located. The second connection order will therefore be sent to the second stratum. Control logic associated with the second stratum will examine the network of the second stratum to see if a connection can be established between the access points. Assume that there are free resources along a path between the access points in the second stratum. The control logic in the second stratum will then establish a connection between these access points. This connection forms an infrastructure for the first stratum. In this way, the infrastructure becomes available for the first stratum at said end nodes. In the following, the infrastructure is then said to be assigned to the stratum. The resources of the infrastructure consist of a number of channel pairs as will be explained below.

In the allocated infrastructure, a channel pair is coated and used to set up the originally ordered connection 10 15 20 25 30 35 504 3:47 '9 while the rest of its channel pairs are ready to be used by future connections.

Thus, an infrastructure is allocated on a demand basis when in the said upper stratum there are no longer any channel pairs available for traffic along a road in the upper stratum but when there is still a need for the establishment of new connections along. said road. When the allocated resources are no longer used by the higher stratum, the infrastructure is returned to the lower stratum and can now be made accessible to the lower stratum. In this way, the combined structures of the two stratums involved in the allocation process are used efficiently.

Compared with before, the resources for the infrastructure will thus be used more efficiently.

According to an embodiment of the invention, the first reference refers to a group of first access points, which are located in the lower stratum, and. the second reference refers to a group of other access points, which are also located in said lower stratum. Between the node at said one end point of the road and each of the first access points a tree connection is arranged. In the same way, tree connections are arranged from the node at the opposite end point of the road to each of the other access points in the second lower stratum. When reference is made to the first and second references, an access point is selected in the group of first access points and an access point in the group of other access points and a connection is set up in the lower stratum, between the two selected access points.- DESCRIPTION OF THE INVENTION The invention appears from the appended claims. . The invention itself, together with other features and advantages thereof, will, however, be described in the special description part, which refers to the accompanying drawings, in which FIGURE 1 is a block diagram of a path passing between two nodes, FIGURE 2 is a detailed view of the road of Figure 1, FIGURE 3 is a simplified schematic view of a stratified network structure in accordance with the prior art, FIGURE 4 is a simplified schematic view of the stratified network structure of Figure 3 modified in accordance with FIG. with the present invention, FIGURE 5 is a block diagram of nodes 10 and 20 in stratum 1 and 1, respectively. stratum 2 in Fig. 4, FIGURE 6 is a list of free resources associated with a path to which an infrastructure can be allocated, FIGURE 7 is the list of free resources shown in Fig. 6, to which list an infrastructure has been allocated dynamically FIGURES 8-10 are flowcharts showing the control logic included in the traffic system involved in the process of dynamically allocating an infrastructure; FIGURE 11 is a routing table; FIG. 12A and 12B are free resource lists which are similar to that shown in Fig. 6, FIGURE 13 is a simplified stratified network used to illustrate a variant of the dynamic allocation process in accordance with the invention, FIGURE 14 is a simplified stratified network and shows an example of an iterative dynamic assignment process, and FIGURE 15 is a schematic diagram showing a second embodiment of the invention. 10 15 20 25 30 35 504 347 ll DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS Fig. 4 is similar to Fig. 3 except that there are two physical connections 4 and 5 between stratum 1 and stratum 2. More specifically, the physical connection 4 goes from ET1 in node 10 to ET4 in node 20. The physical access point to ET4 in node 20 is denoted A1. The physical connection 5 similarly goes from ET2 in node 11 to ET3 in node 21. The physical access point to ET3 in node. 21 is denoted .A2. ON. In this way, two physical connections are created between stratum 1 and 2. In stratum 2, it is possible to set up a connection between A1 and A2 using 2 Mbps connections in stratum 2. As an example, a connection can be made between A1 and A2 over road 23. Another example of a connection between A1 and A2 is to set up a connection using roads 25 and 24. For the time being, and in order to explain the mechanism of the present invention, it is assumed that a control system in stratum 2 receives an order, from another control system (not shown) in stratum 1, to set up a connection between A1 and A2. The operation and maintenance system 29 examines its traffic and finds a clear road between A1 and A2. Suppose e.g. that road 23 is vacant. The control system (not shown) in stratum 2 covers path 23 and connects the ET units at each end of the paved path with resp. ET units where A1 and A2 are located. Such connections are shown schematically with the dashed lines C1 and C2 and are made internally within the nodes 20 and 21. Thus, there is now a 2-Mbps connection 4-A1-C1-23-C2-A2-5 which terminates in ET1 and ET2 . ET1 and ET2 in stratum 1 will now determine the bit rate at which the connection 4-A1-C1-23-C2-A2-5 is operated. Since ET1 and ET2 multiplex at a bit rate of 64 kBit / s, said connection 4-A1-C1-23-C2-A2-5 will also be operated at this rate. The connection will thus add resources in the form of 32 channel pairs to path 13, each such channel pair propagating at the rate of 64 kBit / s and carried by the 2 MBit / s connection in stratum 2. Usually one or two of the added 32 channel pairs are used for signaling purposes. In Fig. 5, the node 10 is shown in detail. In addition to a selector 10, the node comprises a processor 45 and control program 46. Furthermore, there is a database 47 which i.a. contains a network description of the resources in stratum 1. Such descriptions consist of e.g. of 'conventional' routing tables used for routing a leash through a network as well as linking tables of the type shown in Figs. 6, 7 and 12B. Such link tables are used to register the current state of * the individual channel pairs. in an individual way, ie. whether an individual channel pair is busy or not.

The control program module 46 consists of several different programs, including a switch setup program 48 and a resource manager 49. Similarly, the node 20 in stratum 2 comprises a processor 55, a program module 56 and a database 57. The program module 56 consists of several different control programs, i.a. a coupling arrangement program 58, and link tables of the type shown in Fig. 12A.

In practice, the processors 45 and 55 may be physically one and the same processor and so may the case of the databases 47 and 57.

A road in stratum 1 consists of one or more links. Each road includes a road table. Fig. 6 shows a road table 52. As an example, the road associated with the road table 52 is the road 13.

The road 13 consists of two links 40, 41, each of which contains 32 pairs of channels, of which e.g. two are used for signaling purposes.

The other 30 channel pairs are available for traffic. Thus, there are a total of 60 channel pairs for path 13. The available channel pairs are numbered 1, 2 60. Each such channel pair has a status, busy. and non-busy. In accordance with the invention, the weight table 52 has two references, which are symbolically shown at 50 and 51. Each reference represents a relation. More specifically, there are: (i) a first relationship between a first endpoint of the path 13 and a first access point located in a lower stratum, which first endpoint of the path is connected to the first access point, and (ii) a second relationship between the second endpoint of the same path 13 and a second access point, which also which second endpoint is is located in a lower stratum, connected to the second access point. The two access points, A1 and A2 in the example shown, must not coincide but must be located at each end point of the road 13 in stratum 1. In stratum 2, there may be several nodes between the access points A1 and A2.

More specifically, the presence of the reference 50 in the road table 52 indicates that the left end point of the road 13 is connected to the access point A1 in stratum 2, while the presence of the reference 51 indicates that the right end point of the road 13 is connected to the access point A2 in the stratum 2. In accordance with the present invention, the access points A1 and A2, which represent the two end points of the road 13, are to be connected to each other in stratum 2. As described above, such a connection is called an infrastructure.

Allocation of an infrastructure to a higher stratum is initiated when needed when predetermined conditions are met. As an example, allocation of an infrastructure is initiated when all channel pairs in links 40 and 41 have been paved and traffic continues to increase along road 13. As another example, allocation of an infrastructure is initiated when a few, such as Example 5, channel pairs are available in road table 52. and the traffic load along the road 13 is at or above a predetermined level. Other parameters and combinations of parameters can control the time when the allocation of an infrastructure is initiated.

Two different means by which the allocation process of an infrastructure is initiated are proposed in accordance with the present invention. According to one embodiment, the assignment is initiated by an infrastructure of control logic, which is present in stratum 1 or in stratum 2 or in both of these strata. This embodiment was briefly described above and will be described in more detail below. In accordance with another embodiment of the invention, the allocation process of an infrastructure is initiated by a signaling procedure.

A signaling procedure is a signaling 'sonx belonging to: down the access point A1 and which uses an identification of the access point A2 (a roaming number). An example of such signaling is out-of-band signaling.

Another signaling procedure is to order the connection between A1 and. A2 by sending the order to the operation and maintenance system DoU 29 via a traffic management system TMN (not shown), which utilizes the Q3 interface.

In the individual example in Fig. 4, the connection, which constitutes the infrastructure, is set up between the access points A1 and A2.

This connection can follow either the direct path 23 between A1 and A2 or the composite, of the paths 25 and 24, consisting of the path over node 22.

When a connection is established between a user connected to node 10 and another user connected to node 11, a channel pair, e.g. in link 41, to be paved and occupied - marked in the corresponding road table 52. Assume that the traffic increases and that finally all channel pairs 1-60 are occupied. The next connection order requesting a resource in path 13 will trigger an infrastructure allocation process. When the infrastructure allocation process, which is described above, is complete, stratum 1 will now have a link in the road between A1 and A2. The two selector terminals ET1 and ET2 will now provide 30 additional channel pairs to road 13. These additional 30 channel pairs can now be used for traffic originating and terminating in stratum 1. Once said link in the road has been assigned to stratum 1, road table 52 will look as shown in Fig. 7 where the new additional channel pairs are designated 61-90. Among these additional channel pairs, one is selected for the connection that triggered the infrastructure allocation process. As the traffic continues to increase, more channel pairs, among users, the assignment of the link in the road in stratum 2 to said additional channel pairs will be occupied. For a path 13 in stratum 1 invisible, ie. the user cannot distinguish between a connection using link 40 from a connection using a dynamically established infrastructure through stratum 2.

As the traffic decreases and no channel pairs in the assigned link are used anymore, control logic in the resource manager 49 will return the free link to stratum 2 and release the connection Al-C1-ET-23-C2-A2 set up in stratum 2. will described in more detail below in connection with Figs. 8-10. It is assumed that a torque is to be set up between A and B in Fig. 4. Fig. 8 shows the logic of the torque setup program 48 on the left. The above resource allocation process on the right shows the logic of a routing analysis performed using routing tables shown in Fig. 11. A connection order, represented by box 60, is generated when user A dials the telephone number of user B. After conventional number analysis, the destination of the call is obtained. To find the route to the destination, route selection analysis starts, box 61. For route selection analysis in node 10, a route selection table 62 of the type shown in Fig. 11 is used. As the input data for the route selection analysis, the destination of the call, in this case the identity represented by N11, is node 11. At the N11 entry, enter the identities of the roads that can be used to get to node 11. In this case, road 13 must be used, and this road has the identity R13-ID.

The path to be used is indicated by box 63 in Fig. 8 and the process of returning the selected road identities is represented by box 64. The link setup program 48 receives the possible paths, box 65. Thereafter, the link setup program commands that a resource in the first identified path is to be paved, box 66. Since the example described relates to a telephone call, a channel is paved. A channel is a time slot that has a fixed time position from frame to frame. The pavement order is sent, ring 67, to the resource manager 49. The resource manager examines the road table 52, which corresponds to the selected road, to check if there is any available resource. The result is returned to the link staging program, box 68. The result is either a channel is occupied or not. What it was about is determined in 10 15 20 25 30 35 504 347 16 box 69. If resources are available, option YES, the liaison program 48 sets up a connection, box 70. If no resources are available, option NO, try, box 71 , if other paths were given in process step 64. If other paths were given, option YES, examine the first path option, box 70A, to see if there are any resources in this path that can be paved. This procedure is repeated until a path is found that has resources available. This repetitive procedure is illustrated by arrow 7OB. If there is no road among the other scales mentioned that has any free resource, the requested connection is rejected, box 7OC.

Fig. 9 shows the logic of the resource manager 49. Upon receipt of the order to occupy a resource, ring 67, the resource manager examines the corresponding list 52 of available resources to see if there is any available resource, box 72. If a resource is free, option "YES", occupies the resource manager.49 the resource and sends back the link setup program 48, the identity of the allocated resource to which receives the identity of the resource, call 68. If no resource is free, option "NO" at option 72, the resource manager checks if it selected path has any relation to an infrastructure, box 74. If the selected path has no relation, option "NO", the resource manager sends a corresponding message to the link setup program, call 68. If there is a relation, alternative "YES", the resource manager 49 sends information about the infrastructure access points, box 76, to the link setup program 58 in stratum 2, call 77. The link setup program in stratum 2 is shown in Fig. 10 and is in principle similar to that shown in Fig. 8 and will therefore not be described in detail. From the coupling arrangement program 58, the resource manager receives a message, which is symbolized by a ring 78, containing information, box 79, about the result of the coupling arrangement in stratum 2. Either the requested connection was set up or not, alternative YES resp. NO at box 80. If the connection was established, the additional resources, in the form of channel pairs, are added to the table with available resources, box 81, and a channel pair is occupied, box 73, for the one ordered in stratum 1. the connection. The coated channel pair is busy marked in the table with available resources. A corresponding message is sent to the control logic 48. If no connection could be set up in stratum 2, a corresponding message, box 82, is sent to the control logic 48 and the connection order made at the level of stratum 1 is rejected. ring 68.

Fig. 10 shows the control program 58 in stratum 2. Upon receipt of the identity of the access points, a connection order, box 83, is sent to the control logic in stratum 2. This connection order is processed in a manner similar to the manner in which the connection order in stratum 1 was processed. and shown in Fig. 8 and will therefore not be described in more detail. The various processes involved in setting up a connection in stratum 2 are shown collectively at box 84. The result is either that a connection is set up, box 85, or that a connection is not set up, box 86. In both cases, a corresponding message is sent to link manager, call 78.

In the example described above, the number of channel pairs in a path in stratum 1 is expanded by providing the path with a relation to two access points in stratum 2, which access points represent the two end points of a possible connection in stratum 2. In accordance with the present invention, a path , e.g. road 13, in stratum 1 is also expanded by providing the road with a relation to two access points in stratum 3. Such relations which point to the end points of a road in stratum 3 are shown at 87 resp. 88 and Fig. 12A. To set up a connection in stratum 3 and use the infrastructure thus created to expand the number of available channel pairs in stratum 1 has been described above and will therefore not be repeated. Suffice it to say that in this embodiment there would be a first physical connection, similar to the connection 4, between the nodes 10 and 30 and a second physical connection between the nodes 11 and 31. In Fig. 13 the corresponding infrastructure in the stratum 3 has been shown. For the sake of clarity, stratum 2 is not shown in Fig. 13. In this embodiment, there is a first physical connection 93, similar to the connection 4, between the nodes 20 and 30 and a second physical connection 94 between the nodes 21 and 31. The number of channel pairs assigned to stratum 1 in this case is in the order of 2100 because stratum 3 provides an infrastructure carrying 155 Mbps. The access points designated by the relations 87, 88 are denoted A5 resp.

A6.

According to the invention, the number of channel pairs for a path in stratum 2 can be expanded by providing said path in stratum 2 with a relation to two access points in stratum 3. In Fig. 12B, the path 25 is provided with two such references 89. 90.

It is also possible to use the inventive idea repeatedly from stratum to stratum. This is illustrated in Fig. 14. Assume that a connection is ordered from A to B in stratum 1 and that path 13 has no resources available. Road 13 has the above-mentioned relations 50 and 51 to the access points A1 and A2 in stratum 2. Assume further that there are no resources available along road 23 which runs between access points A1 and A2. Along the alternative road between A1 and A2, ie. along the combined road 25 and 24, road 25 is assumed to have no resources available while road 25 on the other hand has two references 89, 90 which are connected to two access points A3 and A4 in stratum 3 via two physical connections 93 and 94. In stratum 3, resources are available and an infrastructure, represented by node interconnects C3 and C4 in nodes 30 and 33 and a path 36 is assigned to stratum 2. The connection requested in stratum 1 is set up using a connection set up in stratum 3.

Fig. 15 shows another embodiment of the invention. In Fig. 15, the architecture of stratum 1 is substantially the same as in Fig. 3.

From each of the nodes 10, 11 and 12, however, a number of physical connections are made to selector terminals ET, which occur in the second stratum 2. This second stratum 2 is symbolically shown by the area enclosed within the line 22. Node 1 has four such physical connections which are collectively designated 444, node 11 has two such physical connections 555 and node 12 has four physical connections 666. Each physical connection extends between two selector terminals ET. The ends of the physical connections 444, 555, 666 in stratum 2 are symbolically shown by filled circles and are called access points. These access points for the connections 444 are collectively referred to as 93, the access points for the connections. 555 is denoted 94 and the access points for connections 666 are denoted collectively 95. Outside stratun | 2 and between nodes 10, 11, 12 there are roads 13, 14 and 15._Each road has a relation in the form of pointers, which point out the two end points of resp. way. Thus, path 13 has two pointers 99, 100 of which 99 point to the group of access points 95 while pointer 100 points to the group of access points 93. Similarly, path 14 has two pointers 101, 102, which point out path 14 and 14, respectively. endpoints in stratum 2. The pointer 101 points out the group of access points 94 and the pointer 102 points out the group of access points 95. Road 15 has two pointers 103, 104, which point out the path resp. endpoints in stratum 2. More specifically, pointer 103 points out the group of access points 93 while pointer 104 points out the group of access points 95. If a path, e.g. path 15 extending between nodes 10 and 12, needs resources from stratum 2, the link manager 49 selects the group of access points 93 and the group of access points 95, since these two groups represent the end points of a link in the path passing between nodes 10 and 12. In stratum 2 then sets up a connection between the two selected access points.in groups 93 and 95. The individual connection set up in stratum 2 can be selected using a conventional resource allocation algorithm, which examines the traffic along the roads in stratum 2 and which based on this examination choose the path to be followed in stratum 2.

Although three strata 1, 2 and 3 have been described above, the telecommunication network may comprise four strata or more, or only two strata, and the method according to the invention and the practice of the invention could equally well be applied to such networks.

A path can extend over several links, some of which are fixed and some are assigned dynamically in the manner described above. »Hv 10 15 20 504 347 20 The effect of this will be that a road will consist of a fixed number of resources of the type that always occur. In addition to these resources, there are a number of resources that the road can be allocated dynamically.

The control logic for ordering a connection in stratum 1 has been said to lie on stratum 1. and has been said to be executed on a processor, position of a connection in stratum 2 has been said to lie in stratum 2 and has been said to be executed on a processor belonging to stratum which belongs to stratum 1 below the control logic for division 2. However, it is not necessary to divide the control logic and its execution on processors belonging to different strata.

The invention can be applied just as well if one and the same processor executes control logic for the two stratums and it does not make any difference if the processors belong to one stratum or the other. The processor can also be distributed over several nodes in the same stratum. Above, the control logic has been described as being divided between different stratums, but in accordance with the present invention, it may be integrated and may execute on a single processor or on a distributed processor. The control logic, whether structured in multiple strata or not, and the processor, whether it is a single processor or a distributed processor, on which the control logic executes form a control system for the telecommunication network.

Claims (11)

lO 15 20 25 30 35 504 347 21 PATENT REQUIREMENTS A method for dynamic resource allocation in a stratified network structure, comprising a dynamically connected first stratum network (1) with selector structures (10, 11, 12), first paths (13, 14, 15) and user access units, at least one second stratum network (2, 3 ) located below the first, overlying stratum network and comprising nodes (20, 21, 22; 30, 31, 32, 33) and other paths (23, 24, 25; 34, 35, 36), which first and second stratum networks forms a traffic system, a road (13) in the first stratum network comprising a first number of resources, characterized in that at least one first (13) of said first roads is provided with a first relation (50, 51; 87, 88 ) pointing out two access points (A1, A2; A5, A6) in the second stratum network, establishing a connection (A1-23-A2 or A1-25-24-A2 or A5-36-35-34-A6) between the access points in the second stratum network (2, 3), which connection comprises a second number of resources, hereinafter referred to as an infrastructure, in response to predetermined traffic-sensitive conditions along the first road are met, as well as the allocation of infrastructure to the first road (13). A dynamic resource allocation method according to claim 1, characterized in that (1) the first relation (50, 51) is associated with a first and a second end of the first path (13), (2) that the first the end of the first path is connected to a first node (10) in the first stratum (1), (3) that the second end of the first path (13) is connected to a second node (11) in the first stratum, (4 ) that the first node (10) is provided with at least one first physical connection (4) extending between the first node and the first access point (A1) in the second stratum network, (5) that the second node (11) is provided with at least a second physical connection (5) extending between the second node and the second access point (A2) in the second stratum network, (6) and that the first and second access points (A1, A2) in the second stratum network are connected to each other. lO 15 20 25 30 35 504 347 22 A dynamic resource allocation method according to claim 2, characterized in that the first access point (A1) is selected from a first group (93) of first access points each having a single physical connection (444) to the first node (10). ) and that the second access point (A2) is selected from a second group (94) of access points each having a physical connection (555) to the second node (11). A method for dynamic resource allocation according to claim 3, characterized by the initiation of said connection (Al-23-A2) traffic system controlling said first and second stratum networks. from control logic (46) which is part of a Method of dynamic resource allocation according to claim 1, characterized in that (a) a second path (25) in the second stratum network (2) is provided with a second relation (89, 90) pointing out two second access points. points (A3, A4) in a third stratum network (3), which lies below the first and second stratum networks (1, 2), and (b) that the second path (25) is allocated to the resources of a third connection (A3-36). A4) set up in the third stratum network between said second access points (A3, A4) in response to the fulfillment of predetermined traffic sensitive conditions along the second road (25). A method for dynamic resource allocation according to claim 5, characterized in that steps (a) and (b) are repeated for successive underlying stratum networks. A dynamic resource allocation method according to claim 2, characterized in that the traffic sensitive conditions are met when a predetermined number of the first number of resources in the first wave are occupied. A dynamic resource allocation method according to claim 5 or 6, characterized in that the infrastructure is returned to the second stratum network when all of the second number of resources have been released. System for dynamic allocation of resources in a stratified network structure, comprising a first stratum (1) with selector structures (10, 11, 12), trunks (13, 14, 15) and user access units, a second stratum (2 ) comprising nodes (20, 21, 22) and trunks (23, 24, 25), a first path (13) in the first stratum having a first number of resources, characterized by at least one first physical connection ( 4) extending between a first node (10) in the first stratum and a first access point (A1) in the second stratum (2), at least one second physical connection (5) extending between a second node (11) in the first stratum and a second access point (A2) in the second stratum, traffic intensity sensitive means (52, 49) for initiating the establishment of a connection (A1-23-A2) between the first and second access points (A1, A2) in the second stratum (2). A system for dynamic allocation of resources in a stratified network structure according to claim 9, characterized in that the first and second physical connections both carry the same connection bandwidths. A system for dynamic allocation of resources in a stratified network structure according to claim 9, characterized in that said traffic intensity sensitive means comprises a list (52) of available resources, which list is associated with the first road and comprises (a) a list of each of the first number of channel pairs and status (busy / non-busy) of each of the channel pairs, (b) a relationship (50, 51) comprising two references, each reference pointing out each of said first and other access points (A1, A2) in the second stratum.