CONTROL OF TELECOMMUNICATION NETWORKS Related Request This invention relates to the request of TW Anderson and collaborators: "Merging the Functions of Switching and Cross Connect in Telecommunications Networks" (Fusion of the Switching and Cross Connection Functions in Telecommunications Radios) presented concurrently and assigned to the assignee of this application. Technical Field This invention relates to methods and apparatus for controlling a telecommunications network, comprising a plurality of individual telecommunications switching systems. Problem The recent decades have continued to notice a marked increase in the amount of telecommunications traffic, especially that which is carried out by the largest quota networks. Networks such as the AT & T network, cover a large area and require a substantial number of nodes, just to reach the local and tandem switches to which they are connected. Adding more nodes, just in order to handle additional traffic, is very expensive; each additional node in the AT &T quota network contributes substantial operating costs, administration, REF: 23943 maintenance and supply for aggregate interconnectivity, and for separate operation of the switches in each node. The capacity of a node is determined by the circuit capacity of the switches in the node, the capacity is limited by the number of terminations that can be supported by the node and by the capacity to handle traffic of the processor system to control the node. Modern telecommunication services require increasingly large amounts of data processing to handle each call in order to allow services from clients whose implementation may depend on data referring to both the calling and the calling parties being offered. The implementation of these services is a necessity in a competitive market. In addition, the larger the node, the higher the reliability required. One problem of the prior art is the limitation in the size and reliability of the nodes of a telecommunications network due to limitations that are obtained by the capacity and reliability of data processing required to offer the modern telecommunications service. The above problem is considerably alleviated and an advance is made against the prior art according to the applicant's invention, wherein the network is broken down into a plurality of switching fabric systems (switches), each with control processors of tissue to perform basic functions (establish connections between terminals of the switch, connect announcements to a terminal of the switch and in the specific modality of the applicant, carry out a busy test and a search for a trunk available in a group of trunks); the control of call services and the control of decisions as to which connections are made, are relegated to a separate group of switching processing platforms (SPPs); the SPPs and switches are interconnected by a high-speed data communications network such as an ATM network (asynchronous transfer mode). Advantageously, an SPP can control a call of a plurality of switches from an entry node to an egress node of the network. Advantageously, this allows a single control process in a single SPP to control all the connections from entry to exit. Advantageously, a small amount of SPPs simplifies administration. Advantageously, the reliability is improved since a plurality of SPPs can control calls of a switch. In accordance with the preferred embodiment of the applicant, trunk searches in a specified trunk group or set of trunk groups are performed in an individual switch. Advantageously, the dynamic change record of these trunks are available, it is kept only in one place, thus simplifying the updating of this record.
According to a preferred embodiment, entry CCS7 initial address messages are routed over an SS7 network to one of the SPPs. The call is assigned to a call processor in any of the SPPs and this call processor receives the data from the initial address message over an intra-SPP or inter-SPP ATM signaling network. The call processor then accepts an appropriate database in any of the SPPs, to obtain the translation data for the called number and, if necessary, the calling number. The calling processor then signals the input and output switches of the network to request a connection between the entry trunk and the egress trunk or destination directly connected to the egress switch. The ingress switch and the egress switch identify trunks used to interconnect these switches to the call processor, which then send commands to these switches and any intermediate switches in the connection to establish the connection between the ingress and egress switches, and to connect the main entrance and exit destinations. The trunk search and the selection of an intermediate switch, if necessary, are carried out in the conventional manner of the prior art. The egress switch has the responsibility to choose an egress trunk within a trunk group, specified by a call processor. The ingress and egress switches are responsible for choosing the intra-network trunk groups and for performing the required addressing within the network, as prescribed for example to implement real-time network addressing described, for example in the patent of the USA No. 5,101,451. Each switch has the responsibility to establish connections within the switch. Advantageously, this arrangement avoids the need to ship large amounts of data to the call processor and to avoid race conditions. The switch also manages service circuits, such as digital receivers and announcement systems, and verifies all connections in order to discover disconnections and request disconnection action from the call processor. If the switch collects digits, these digits are sent to the call processor for further processing. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a block diagram of an illustrative embodiment of the applicant's invention; Figure 2 illustrates the call control flow; and Figures 3 to 9 are flow diagrams of actions performed by signaling link processors (SLPs), switching processors and call processors (CPs).
Detailed Description Figure 1 is a block diagram illustrating the operation of the applicant's invention. The blocks 10A, ..., 10B are Switching Processing Platforms (SPPs) for controlling a large network such as an AT &T quota network. The switches of the fee network are fee switches 40A, ..., 40B. In the preferred embodiment, these switches are switches with pulse code modulation (PCM), but in alternate modes, these switches can be analog or ATM switches. The SPPs are interconnected by and connect to a signaling network 20, which transmits the signaling message of the signaling system 7 (SS7). Each SPP contains a plurality of call processors (CP) 11, a signaling link processor (SLP) 12, an administrative processor (AP) 13, and optionally a network control point / service processor (SP / NCP) ) 14, which usually includes a database; These are interconnected by a local area network ATM, ATM / LAN 15. It should be noted that while the diagram shows a single signaling link processor in each SPP, these processors can also be duplicated in such a way that at least two of those Processors exist for reliability. The administrative processor is used to take measurements and to control changes in the data stored in call processor databases. The database of the administrative processor also contains backup data to initialize any call processor. The quota switches and ATM local area networks are interconnected by an ATM signaling network 30. The signaling network SS7 20 also communicates with networks outside the quota network such as local networks. The arrangement makes it possible for any call processor to serve a call on any switch or any plurality of switches in the quota network. The use of the ATM signaling network, which with modern technology can transmit signaling messages very quickly, makes it possible to exchange many messages between a call processor and the fabric processors of the quota switches for a single call, and also makes it possible for a call processor to access data in any database of any SPP quickly. The control system is therefore very robust since any call processor in any of the SPPs can control a call and can have information from any database in its own SPP or other SPPs. The operation of the call is illustrated in the following description. An initial address message (IAM) the first signaling message announcing the arrival of a call in an ingress trunk, is received in the signaling network SS7, 20, and is routed through this network to a signaling link processor appropriate (SLP) 12 in one of the SPPs. The selection of a call processor by the SLP is based on the availability of both capacity and feature functionality in each of the call processors across all the SPPs, and can be influenced by the location of the CP in order to minimize the number of remote data accesses for a particular call and minimizing the elapsed time to transmit control messages between the CP and the switching processors. The signaling message is transmitted by the initial signaling link processor 12, to the select call processor 11 via the ATM network 30, if necessary, and the ATM / LAN 15 of that SPP. The call pin accesses data from its own database or, if necessary, the database of its own SP / NCP 14 or the SP / NCP of another SPP, and, based on the information obtained, makes a decision to choose a discharge destination from the quota network to connect to the revenue trunk associated with the initial address message. An egress destination in this case is specified by a terminating directory number. The quota switch that connects to the entry trunk is identified by information in the IAM. In the preferred embodiment, the call processor chooses an egress switch, the egress trunk group or an address index to choose a preferred trunk group and alternate trunk groups. In the preferred embodiment, the selection of an output trunk, and if the output trunk is not connected to the egress trunk switch, the selection of the quota network path used to reach the quota switch connected to the trunk of the trunk. output, it is done under the control of the quota switches. These switches have up-to-date information regarding the availability of trunk trunks and inter-trunk trunks, information that would be difficult to make available to all call processors in a timely and easily accessible manner. In this way, the process of choosing an output trunk and, if necessary, an intermediate switch within the quota network, is carried out under the control of the switching processors 41A, ..., 41B of the quota switches. These tissue processors communicate with each other over the ATM 30 signaling network in order to choose trunk to reach the egress quota switch and the egress quota switch chooses the outgoing trunk. Alternatively, the tissue processors can communicate with each other over the SS7 network to be consistent with prior art assemblies. In the preferred embodiment, the principles of network addressing in real time, as described in US Pat. No. 5,101,451, are used to choose a trajectory within the quota network. The quota switches communicate with each other over the ATM signaling network 30, and send messages over the ATM signaling network to the control call processor requesting that its associated signaling link processor transmit the appropriate SS7 message over the SS7 network, 20, to a switch in the connected network. While in the preferred embodiment any call processor can handle any call, certain savings can be obtained if individual call processors are restricted to call processors that originate in a subset of the network's quota switches. For example, in a geographically large network, it is convenient for call processors to process calls from switches that are relatively close in order to minimize the delay introduced when transmitting messages between processors and switches. Switching processors such as 41A and 4IB of the quota switches are responsible for the tissue control. This includes the control of physical equipment diagnostics, fault handling, and other maintenance actions related to network fabric; trunk management includes maintenance of the state of the trunks and controls the maintenance of the trunks; direct translations, path searches and path selections when a connection within the network requires two or more switches; circuit and service management, including providing advertisements;
collect digits that are designated outside the SS7 protocol; establish conference connections; and verify existing connections to detect additional control signals. The switching processor is also responsible for establishing a connection between the network endpoints with special connection attributes as defined by the service class. Examples include clear data of 64 kilobits (as opposed to voice) and calls directed only on cable trunks (as opposed to microwaves) to achieve more secure communication. The service logic, which is implemented under the control of the call processor, is responsible for controlling connections with one or more endpoints and managing user services in these connections. Indeed, each channel between a switch and a network endpoint can be considered as a conference port; the service logic is then the conference controller. Specifically, the service logic performs all translations of service-related digits (as opposed to addressing) performs call processing for basic calls, performs translation and class calls service requirements 800 and 800 advanced; controls the network defined by software; and controls network services that are based on the calling subscriber as well as the called telephone number.
Figure 2 is a general functional view of the applicant's invention. Entry signaling is routed to a logical service director (the signaling link processor) which, based on the calling or addressing number (such as the POTS number corresponding to an 800 number) and the directory number of caller, as distinguished by the automatic number identification (ANI) chooses a call processor to service that call. For example, a set of specialized processors can process all 800 calls. The call processor communicates with the switching processors (the processors of the quota switches). The call processors and the tissue control processors generate output signaling messages for transmission to a terminating network. The load on the call processors is a primary factor influencing the selection of a specific call processor in a group. Figure 3 is a flow diagram illustrating the operation of the signaling link processor (SLP) required to implement this embodiment of the applicant's invention. The SLP receives a message from the signaling system network 7 (SS7) (action block 300). The SLP tests whether this is an initial address message (IAM) (test 302). If this is an IAM message, then the SLP chooses the call processor to process the call represented by the IAM (action block 304). When making the selection, the SLP takes into account factors such as the load in the various CPs, the physical proximity of a CP to the switch that contains the trunk for which the IAM is received, special characteristics of the call that may require that the call must be processed by a specialist CP (for example, if 800 calls are assigned to a group of specialist CPs). Also, it is convenient to use a CP in the same SPP as the SLP. The SLP sends a message to the processor of the switch that serves the trunk for which the IAM was received, to identify that switch that the CP has chosen and to mark the busy trunk (action block 306). The SLP updates its table referring to individual trunks to the CP services calls for that trunk (action block 308). The SLP then sends the IAM to the CP and activates the CP for that call (action block 310). If the result of the test 302 is to indicate that this is not an IAM message, then the SLP searches for the identity of the CP that handles the call to which the message refers when searching for the identity of the CP for the trunk of the message (action block 312). Test 314 checks whether the CP is in fact identified in the SLP trunk table. In that case, then the SLP sends the message received in block 300 to that CP (action block 310). If the CP is not identified (negative result of the test 314) then the SLP interrogates the switch serving the trunk for which the message has been received in order to obtain the identity of the CP of that switch (action block 316). This can happen if the SLP receives messages for the trunk that fails, in which case a different SLP will start receiving messages for the trunk. When the SLP receives the identity of the CP from the switching processor, the action blocks 308 and 310 are executed as described above. Figures 4 to 7 are flow diagrams of actions performed by the switching processor serving a trunk for which the SLP receives the message. The action block 400 indicates that the switching processor has received an interrogation of the SLP for the identity of the CP serving the call transported on a particular trunk. (This is an interrogation sent by the SLP in action block 316 of Figure 3). The switching processor searches for the identity of that CP in a table, using the identity of the trunk to set the table (action block 402). The switching processor then responds to the SLP with the identity of the CP (action block 404). Figure 5 illustrates the actions taken in response to receiving a request to assign a specific CP to a trunk, the request is received from an SLP. The request is received (action block 420) by the message transmitted by an SLP in action block 306 ((Figure 3) previously described). Test 422 verifies if the trunk was already assigned to a CP. If not, then the trunk is marked busy and the trunk is updated to the CP table (action block 424). The switching processor then sends a message to the CP confirming an assignment of that CP to that trunk (action block 426). If the trunk has already been assigned to a CP, this is an indication of a "reflex" situation (action block 430). This situation occurs when the two ends of a trunk are taken almost simultaneously. In the preferred embodiment of this invention, this situation is handled by assigning a preferred endpoint of each trunk for which a reflex may occur (a reflex will not occur in a trunk of a channel). If the mirror is at the preferred end, the switching processor sends a message to the call processor that is chosen to process the IAM received from the trunk, indicating that the trunk can not be used for this call and to discard IAM. The switch on the other end will then look for another trunk or direct the call to excess capacity. If the reflection is at the non-preferred endpoint, the switching processor releases the reserved connection reserved for that trunk and sends a message to the call processor that previously spoke that trunk for an outbound call, to indicate that the trunk can not be used more for that call and that the call processor requires requesting a search by another trunk or to direct the call to a tone of excess capacity. The switching processor updates the trunk to the CP table with the identity of the CP that is chosen to process the IAM that is received from this trunk, and sends a message to that CP confirming the assignment of that CP to that trunk. Figure 6 is a flow diagram illustrating the process of choosing a trunk to establish a call. This selection is carried out by the switching processor according to the applicant's preferred mode. The call processor analyzes the called number and uses the code translation of the exchange, deriving an address index that represents a list of trunk groups or an identity of an egress switch that is used by the switching processor to choose a trunk (action block 450). The list can contain groups of trunks to send out the network that are connected to an end exchange or a tandem exchange to reach this end exchange; or an identity of an output switch in the quota network, such that the switching processor may choose a direct trunk to this output switch or a trunk to an intermediate switch of the quota network (in accordance with the principles network addressing in real time as described in the previously mentioned patent). The switching processor, after having found a trunk, reports to the call processor the identity of the trunk found, and reserves a connection to that trunk found, or if necessary, reports a failure for the call processor to take other actions to complete the call or return excess capacity tone (action block 452). The connection is reserved instead of being established in such a way that a complete connection is reserved until a response signal is received at which time a reserved connection is converted into a current connection. The switching processor updates the trunk table with the identity of the call processor if a trunk has been found (action block 454). Figure 7 is a flow chart describing actions performed by the switching processor to perform some type of function in or for a trunk (action block 470). A request is received from the call processor to perform a function on that trunk. The function can be the establishment of the connection to the trunk inside the switch for which the connection was previously reserved. This is the function performed in response to a response signal received from the call exchange. Another function is the reproduction of an advertisement in a trunk and the collection of digits marked by the client in response to the announcement. The switching processor performs this function in or for the trunk (action block 472) and, if necessary, for example, if the request is to put a trunk in standby, update the trunk to the table to indicate that the trunk is now at rest, that is, it is not associated with a CP (action block 474). Figure 8 is a flow chart of actions performed in a call processor in response to receiving an IAM from an SLP (action block 500). The call processor determines a trunk group list from the call number for the switch serving the trunk for which the IAM is received (action block 502). The CP then requests (action block 504) the switch for which a list was determined, which provides the identity of a trunk found in response to the search request of 450 as reported by the action block 452 (Figure 6) . The CP then updates the path information for the call, to indicate that a path has been reserved between the trunk of the IAM and the trunk whose identity is provided by the switching processor of the IAM trunk (action block 506). The 508 test verifies whether the identified trunk is a trunk of the quota network or goes directly to the destination. If not, then the CP determines a list of trunk groups from an intermediate or egress switch to the destination (action block 510) and the actions of the action blocks 504 and 506 and of test 508 are repeated. Eventually, the test result 508 will be positive (ie the identified trunk leaves the quota network, then the CP requests an SLP for trunk output that s the IAM to the switch connected to the trunk output (egress) (block of action 512.) Figure 9 illustrates the actions performed by the CP in response to receiving a characteristic message from an SLP (action block 520.) The characteristic message may be a message indicating a call response, requesting the addition of another branch to the call, requesting to sinformation to any party (for example to identify the other party) or requesting the reproduction of an announcement to request spoken or marked information from the client.The characteristic request message is processed by the CP (block of action 522) and the CP, if necessary, s a message to one or more switching processors, to request the necessary actions to carry out the characteristic requested (action block 524); if necessary, a signaling message is sent to the SLP that signals another switch outside the quota network, in order to accommodate the feature (action block 526). It is noted that in relation to this date, the best method known to the applicant to carry out the aforementioned invention, is that which is clear from the present description of the invention.
Having described the invention as above, property is claimed as contained in the following: