FI108768B - Call routing in communication networks - Google Patents

Description

108768

Call routing on communication networks Samtalsrouting 1 communications

Field of the Invention

The invention relates to call routing between networks, and more specifically, but not exclusively, to call routing between two or more telecommunications networks using different types of addressing systems.

BACKGROUND OF THE INVENTION At present, the majority of calls between two subscribers are carried out using conventional circuit switched telephone systems. The oldest and by far the largest existing telecommunications network is the public switched telephone network (PSTN), which for a long time was the only available bearer network for telephone communication. However, in recent years, there has been a rapid increase in the number of mobile users using different mobile networks (Public Land Mobile Networks, PLMNrt) that provide mobility to their users. Other ·, ·. bearer networks for voice communication include arrangements such as ISDN (integrated service ···. services digital network), asynchronous mode (ATM), frame as relay and Internet.

• * *

In the circuit switched telephone system, such as the PSTN, are required to form a call between the calling party (A number) and the called party (B-number) for some I -... signaling and switching functions for influencing the hydrodynamics defined in order to ... (the call is properly routed A the-number terminal and the B-number terminal to the current telephone systems called · 2 108768 Suva party's A-number and the call to the called party's B-number between the basis of the B-number is routed by the calling party to provide a network system in this context may be the ITU-T..: The signaling system # 7 (SS7) is cited as an example of a modern signaling procedure used for digital circuit switched connections for common channel signaling (CCS) .The common parameters of routing information will be described in more detail below.

In addition to voice traffic, i.e. traditional telephony, existing data communication networks are also capable of transmitting data.

'Most often this is accomplished by packet switched data networks! which transmit data in the form of data packets.

Data networks based on the X.25 protocol (e.g., PSPDN, packet switched public data network!) Or the Internet are mentioned herein as examples of packet switched data networks. Of these, the Internet can be defined as a global packet switched off-line network consisting of interfaces between thousands of subnets (i.e., various local and regional networks; LANs, MANs, etc.) that use TCP / IP protocols (engl). transmission control protocol / Internet protocol proto-col suite) and common address structure. Unlike transfer ·; ·. technologies such as X.25, frame relay and most ATM applications are an Internet end-to-end application that extends to the user's terminal.

. '.. t When establishing a connection between two terminals .... connected to a TCP / IP data network, routing is achieved by using an Internet Protocol address (IP) provided by TCP / IP, which indicates the desired network-connected destination. terminal. The source and destination of the transmitted datagram are identified using fixed-length IP addresses, which are included in the datagram's IP header. The length of the IP address depends on the version used and is, for example, four octets in IPv4 (IP version 4) and 16 octets in IPv6 (IP version 6). The IP address consists of two parts, the network part and the main computer part.

The data in addition to the packet-switched network can also be used to sound, such as speech transmission between two communicating parties. When transmitting audio over a data network, the audio is digitized and transmitted in digital form as data packets. The digitized audio is then converted back to analog form and reproduced at the receiving end by the listener.

Existing systems are also capable of transmitting voice between terminals connected to a variety of networks, such as a local area network (LAN) and the Internet.

Prior art LAN telephony arrangements require a Private Branch Exchange (PBX) to connect the LAN to a public telecommunications network used for communication outside the LAN. The PBX has a special routing table for the IP addresses of the terminals connected to the LAN (i.e., LAN, *, ···. Phones). When playing LAN, ··, ·. to the phone, the caller calls the PBX and then the call is routed to the desired terminal using the PBX routing table. However, such an arrangement such as LANs cannot be implemented for calls with a called terminal or a calling terminal directly connected to a traditional telecommunications network such as PSTN.

i * I f »I <,,>> ► 4 108768

Summary of the Invention

Recent developments in telecommunication systems are leading to solutions in which telephone networks and data networks are interconnected so that calls can be made from a telephone network to a data network and vice versa. However, the real unsolved problem relates to the manner in which calls are routed from a network using a particular type of addressing system to a network using a different type of addressing system. This is the case, for example, when routing from the PSTN to the Internet, i.e. when the calling party is connected to a standard public circuit switched network using the B number for addressing purposes and the called party is connected to a data network using a different addressing system, e.g. the call between the subscriber is transferred over the IP network.

The object of the invention is to overcome the drawbacks of the prior art I solutions and to provide a new type of solution for routing calls between different networks.

... It is another object of the invention is to provide a solution that allows the calling party is allowed to call the different types of the addresses behind the warning system using the network to a called, ···, a terminal in a way that is similar to calling «», ·· ·. called terminal to the calling party terminal is expensive lousy addressing system.

The objects are achieved by a method of establishing a connection between a first point in a circuit switched network and a second point in a packet switched network, wherein data in the circuit switched network is routed using signaling information and data in a packet switched network is routed using data network addresses, the method comprising including signaling information for a plurality of unique connections in the circuit switched network and corresponding packet switched network data network addresses for initiating a connection using said signaling information from said first point to said second point using a duplicator to transform, data network address to signaling information conversion table! using.

In still other embodiments, the signaling information parameters include at least one message signaling unit (MSU) signaling information field (SIF) parameter, preferably at least one of the following: a starting point code (OPC).

originating point code), address point code (DPC, desti -... Nation point code), cord identification code (CIC).

Circuit Identification code), domain name (NI, network indicator), requesting country code (RCC, requesting country '* ··, code). The signaling information may consist of a combination of an origin point code (OPC), an address point code (DPC), a lead t identification code (CIC) and a domain name (NI). The packet switched data network is preferably the Internet, whose addresses, ···, are formed according to the IP address protocol. Signaling / ··. the parameters and the data network address information may be stored in the signaling server and a comparison of the routing parameters and the address information in the signaling server may be performed. The call

f I

· * 6 108768 set-up signaling can be routed to the signaling server and the voice path is routed directly to the destination exchange.

According to another aspect, the invention provides a communication system comprising a circuit switched network in which data routing is based on routing information parameters, packet! a switched network in which data routing is based on data i | network addresses, inter-network access node, [signaling node storing the routing information I parameters that form unique combinations for the set of connections, and corresponding data network addresses, wherein the signaling node is arranged to map unique combinations of routing information parameters and to obtain the desired address point from the circuit switched network to the packet switched network or vice versa.

In yet another aspect, the invention provides a signaling server including a conversion table having signaling information for a plurality of unique connections in a circuit switched network and corresponding network addresses in a packet switched network, wherein the signaling server is arranged from the first point to the second point using the signaling information. for the connection started i - t · * ·, to convert the signaling information to the data network address I * using the conversion table mentioned and to use the data network address for the connection started from the second to the first point to convert the data network address, ···. signaling information.

| * t

The invention provides a reliable and manageable method for routing calls between · 1V terminals connected to different types of networks. The public telecommunications network user can \\ * t 7 108768 conspicuously use regular telephone numbers instead of having to use addresses of a different type than those provided by, for example, ordinary telephone numbers | he is used to calling a terminal that is actually behind a packet switched network. In addition, the invention enables handover when moving within an IP network.

The invention and other objects and advantages thereof will now be described, by way of example, with reference to the accompanying drawings, in which like features throughout the drawings are denoted by like reference numerals.

Brief Description of the Drawings

Figure 1 is a schematic representation of a communication system having a circuit switched telephone network and a packet switched data network and the necessary gateway hardware;

Figure 2 shows the main functions of the SS7 layers;

Figures 3a and 3b are schematic representations of the message parameters of a TUP message and an ISUP message, respectively;

Figure 4 is a schematic representation of a table included in the routing server; *, ···; , *, · ·, T »>. FIG. 5 is a flow chart illustrating the operation of one embodiment of the invention; and, * * * ·. · »Figure 6 illustrates ISUP signaling sets.

t »»> * », ft *,» · I »» t t l t »s» *>> * I ·, I Iti 8 108768

Detailed explanation of the figures

Figure 1 is a schematic representation of a single telecommunications network system comprising two different telecommunications networks, namely PSTN 1 and the Internet 2. Of these, PSTN is a general circuit switched telephone network which appears to have a plurality of telephone exchanges, such as local exchanges 4 and throughput terminals 6. 8 and 8 'are connected to their respective PSTN systems via exchanges 4 and 4' via telephone lines 9.

In a digital circuit switched telephone network, network signaling is typically, but not always, implemented! by means of the ITU-T (International Telecommunication Union, Telecommunication Standardization Sector) Common Channel Signaling System Number 7 (SS7 or C7), which is a worldwide telecommunications standard. SS7 defines the procedures and protocol by which network elements in a PSTN exchange information through a digital signaling network to provide call set-up, routing, and routing, both over wires and wireless. There are several national variants of SS7, such as ANSI and Bellcore in the US and ETSI in Europe.

} ·, * I> * SS7's hardware and software functions are divided into functional. I> abstractions, i.e. levels or layers, that correspond to the OSI (International Standards Organization) OSI (Open System Interconnection) »* Nect) 7-layer model. Each layer is dedicated to the specified purpose, compare Figure 2, which illustrates the main functions of each layer. The first three times »,» * I t) »*> r *» * · • · 9 108768 rosta contain a message transfer part (MTP). Of these, layer 1 defines the characteristics of the signaling channel, layer 2 provides the error-free end-to-end message transmission over the signaling channel, and layer 3 provides message routing between the signaling points in the SS7 network. As shown in Figure 2, the layers include 4-7 ISDN User Part (ISUP) and / or Telephony User Part (TUP) and / or some Application Part / Transaction AP / TCAP. Capabilities Application Part) and SCCP (Signaling Connection Control Part) depending on the type of signaling used.

An SS7 message is called a message unit (SU), which is used to carry signaling messages between different nodes in a telecommunications network. There are three types of message units at SU: Fill-In Signal (FISU)

Units), Link Status Signal Units (LSSU), and Message * Signal Units (MSU). Of these, the MSUs carry all call control, database query, response, network management data, and network maintenance data in a sig nalling information field (SIF). MSU has a service indicator I * ·.! '. service indicator and bus address information.

\.! t routing label information), which covertly determine the destination of a specific data packet. The MSU also transmits signaling messages on the signaling channels, said MSUs conforming to standardized data packet formats for transmission ···. and for processing in the MTP (in the message transfer section).

The MTP layer 3 routes the messages based on the address of the bus - * ,,, in the SIF of the MSU. The bus address comprises a destination point code (DPC), a source code (OPC, 108768 originating point code) and a signaling link selection field (SLS). Point codes are numbers that uniquely identify each signaling point on the SS7 network. When an address point code in a message indicates a receiving signaling point, the message is applied to the appropriate user section indicated by a service indicator (SI) in the SIO (Service Information Octet). Messages destined for another signaling point are transmitted provided that the receiving signaling point has messaging capabilities. The selection of the outgoing channel is based on the information contained in the DPC and the SLS.

Figure 3a shows the structure and main contents of a single MSU. The SIF (signaling information field) and SIO (service information octet) in the MSU contain information which are mandatory parameters of the TUP (telephone section). More specifically, the SIF has the following information parameters: an origin point code (OPC), an address point code (DPC), and a line identification code (CIC). It should be noted here that CIC is only necessary for ISUP / TUP and is not required in SCCP. The SIO, in turn, has parameters such as • · * network indicator (NI) and service indicator (SI). As already.! ! explained, the OPC indicates its signaling point (SP).

signaling point) identity, which is the signaling message (· the sender and DPC indicate the identity of the receiving SP.! .. t CIC in turn indicates its trunk I »t connection) (for speech, fax, data) ···, the number identity to which a particular message belongs and the time slot that is controlled by this MSU »t I · (i.e., the backbone connection booked by the calling center to carry the V .. call). NI indicates the signaling network • »· 11 108768 (national or international) to which the signaling message belongs.

The ISUP IAM (Initial Address Message) has similar parameters as shown in Figure 3b (see also Figure 6). PSTN IAM is sent in the forward direction (in english the forward direction.) By each switching point, which is needed to establish a connection between two parties until the destination node point is connected. IAM includes the compulsory portion, the called party number. It may also be an optional portion, contains the party name and number of the calling. (For more information on ISUP messages, see, for example, ITU-T Recommendation Q.763).

Referring now to Figure 1, a data processing device 10 is connected to the Internet 2 via interface 14 in a manner known to those skilled in the art. One skilled in the art will recognize that there are several alternatives to providing Internet access: ways such as modem or ISDN

Services Digital Network connection) or Internet connection -... t via an inbound server connection (IAS connection), but since the method of accessing ^ the Internet or such a packet switched data network is not an essential part of the invention, is not a private, ♦ more specific.

The system is also equipped with a gateway node, or · *. a connection server 12 which serves as an interface between the PSTN, ···, and the Internet. In this context, it should be noted that although the networks may be represented as physically separate networks, the network arrangement may be such that the PSTN network cabling is also used for the actual transmission of Internet data, i.e. the PSTN acts as a bearer for TCP / IP traffic. Transport Control Protocol / Internet Protocol traffic).

On the Internet, addressing is based on IP addresses according to the TCP / IP series (Transport Control Protocol / Internet Protocol suite). TCP / IP operates on the principle of layered communication (cf. Open Systems Integration, hence the OSI model). TCP / IP communicates without connection (meaning no connections are made through proxy nodes, even though a logical connection between client and server is established). The functions of the IP protocol layer 3 allow communication over a plurality of interconnected networks. The network layer contains functions for routing and addressing. Without going into detail here, the source and destination are identified using fixed-length IP addresses contained in IP headers, as explained in the background section of this specification.

Each Internet host computer and router has ·; ·. own IP address. Currently, all Ipv4 addresses have an I · «length of 32 bits. The addresses are located in the source and destination • • fields of the IP packet. Only part of the address is used for the actual routing process, namely. ··. *. network address. IP addresses are divided into five categories A -. ··. ·. E reserved for different purposes, where the length of the network address is a function of the class. Decimals of your computer ·· *. the format of the address is e.g. 130.100.75.19.

The communication system of Figure 1 further includes a network signaling server (SS) 16. This network node contains all routing information of the call, such as the source code (OPC), the address point code (DPC), the network indicator ( NI), Lead Identification Code (CIC), and in some cases also Catch Country Code (RCC). This set of information provides a unique combination that can be compared to the IP address of a terminal communicating over an IP network. In other words, it is possible to describe the IP address based on the relationship between the combination of routing signaling parameters and the IP addresses. This address relationship, which may be implemented in the form of a mapping table, may be implemented on some existing network nodes (e.g., an Intelligent Network (PSTN) or PLMN) or it may be implemented by providing a new server device 16. In general, the arrangement may be such that when the call is established from the terminal 8, the signaling information parameters required for address conversion are provided to the signaling server 16, which then in response provides the IP address.

Server 16 can be local or global. In the event that the address information or the above parameters are updated, the server 16 is notified accordingly.

1 illustrates in more detail an example of a table implemented in signaling server 16. The IP address and corresponding combinations of routing information parameters are described in the table, such that appropriate pairs are found and retrieved on request so that the call can be routed to the desired address, ··· , for a tea with a different shape than the one that calls it, ···. use.

Now, when the user of the telephone terminal 8 connected to the PSTN 1 wants to make a call to a terminal behind the Internet, such as 14 108768, to the Internet terminal 10 connected to the bearer exchange via ISDN, or to a standard telephone terminal 8 ' by selecting the desired telephone number (B-number) of the terminal to be called. The number may include a special prefix or otherwise be formatted such that the network hardware recognizes that this call is not a standard PSTN call, but that the call must be routed to the desired terminal via packet switched Internet. The called terminal may have an IP address instead of a traditional telephone number, or it may be a standard telephone with a standard B number.

Signaling is directed to the gateway or signaling server 16, which includes a routing table and controls the signaling operations according to the principles of the invention. Although some kind of inter-network access node is necessary, e.g., the connection server 12 of FIG. 1 for the user to connect to the IP network, it is not necessary that the signaling passes directly to the access node from the exchange; it is possible to maintain a gateway or signaling server. The actual data transfer and voice bus go directly to the destination but. signaling can be routed by a different route, as in the figure. 1 is shown.

The signaling server associates a predetermined combination of OPC, DPC, NI, CIC, and RCC ... with the desired IP address in the table. This IP address then allows connection to the TCP / IP network and the connection is routed to data, ···. network routers to the desired IP address according to • IP addressing protocols.

t i i

Claims (12)

108768 In the event that the called party is a standard voice terminal, the IP connection is routed and then terminated at the local exchange of the called subscriber (see flowchart of Figure 5). The B-number information may have been included in the IP header and is thus obtained with the data packet, after which the B-subscriber's local exchange routes the call to the B-subscriber using the B-number information of the telephone network. The invention thus provides an apparatus and method for providing a significant improvement in the routing of calls between different networks. It should be noted, however, that the foregoing examples of embodiments of the invention are not intended to limit the scope of the invention to the specific forms set forth above, but rather are intended to cover all modifications, similarities, and variations within the spirit and scope of the invention. provides. A method of establishing a circuit-switched connection. between a first point within a network and a second point within a packet switched network, whereby data is routed in a circuit switched network using signaling information and data is routed in a packet switched network using data network addresses, the method comprising the steps _ ·· *, provide a conversion table containing the signaling, ···. information for a plurality of unique circuits within the circuit switched network and corresponding data network addresses in the packet switched network; »· 16 108768 for converting signaling information from said first point to said second point using signaling information to convert a signaling information to a data network address using said conversion table, and from a second point to a first point using data network address converting a data network address using signaling information. The method according to claim 1, wherein the signaling information parameters (MSU) include at least one, preferably at least one of the output signal code (OPC), the address point code (DPC), the line identification code (CIC), the network indicator (NI), the signaling information field (SIF) parameters (RCC). The method of claim 2, wherein the signaling information i consists of a combination of an origin point code (OPC), an address point code (DPC), a line identification code (CIC) and a network indicator (NI). The method of any one of the preceding claims, wherein the packet switched data network is the Internet, with its addresses formed according to an IP address protocol. • * A process according to any one of the preceding claims; a method comprising storing signaling parameters and data network information in a signaling server and providing a comparison of routing parameters and address information in the signaling server. 17 108768 The method of claim 5, wherein the call set-up signaling is routed to the signaling server and the voice bus is routed directly to the destination exchange. The method of any one of the preceding claims, wherein the connection is routed between the first telephone terminal connected to the public switched telephone network and the second telephone terminal connected to the second public switched telephone network via a packet switched data network. A communication system comprising: a circuit switched network, wherein the routing of data is based on i routing information parameters; a packet switched network in which data routing is based on data network addresses; an interconnection node; a signaling node containing recordings of routing information parameters and corresponding data network addresses forming unique combinations of the connection set, wherein the signaling node is arranged to associate the routing •::. unique combinations of information parameters to data network addresses to obtain a desired address point for a call to be made from a circuit switched network to a packet switched network or vice versa. The system according to claim 8, wherein the unique combination of signaling parameters includes at least one, preferably at least one of the source signaling code (OPC), the address point code (DPC), the line identification code (S) of the signaling information field (SIF) parameters. CIC), Network Indicator (NI), and '/. request country code (RCC). 18 108768 The system of claim 8 or 9, wherein the signaling node is a signaling server or signaling gateway implemented in connection with a local telephone exchange. The system of any one of claims 8 to 10, wherein the packet switched network is the Internet. 12. A signaling server including a conversion table containing signaling information for combining unique connections within a circuit switched telecommunications network, and in a packet switched network. wherein the character output server is configured to convert the signaling information to a data network address from a first point to a second point using signaling information to convert the signaling information to a data network address using a data network address to communicate to a data link address. • ·, Patent crav