WO2006081886A1 - Selection of a gateway by means of a peer to peer method - Google Patents

Abstract

The invention relates to a method for communication in a communication network, wherein the communication network comprises: connection nodes (G1,G2,G3,G4) respectively connected to an external communication system (PSTN, INTERNET, NET XY) and communication nodes (USER 1, USER 2, USER 3), wherein the communication thereof with an external communication system (PSTN, INTERNET, NET XY) is carried out via a connection node (G1,G2,G3,G4). Prior to communication between a communication node (USER 1, USER 2, USER 3) and an external communication system (PSTN, INTERNET, NET XY), a decision is taken using a data bank (P2P) and is stored in a distributed manner on connection nodes (G1,G2,G3,G4) and/or communication nodes(USER 1, USER 2, USER 3). The invention also relates to devices (G1,G2,G3,G4 USER 1, USER 2, USER 3, P2P) for carrying out said method.

Description

description

Selection of a gateway by means of a peer-to-peer method

The invention relates to a method for communication in a communication network, which connection node in each case with connection to an external communication system, and communication nodes, the communication with an external communication system via a connection node, summarizes. Furthermore, the invention relates to devices for carrying out the method.

In communication systems or networks, messages are transmitted from a sender to one or more receivers. The transmission media and protocols used for message transmission depend on the specific configuration of the communication system. Examples of communication systems are radio communication systems such as cellular mobile radio communication systems or WLANs (Wireless Local Area Networks), or wired communication systems such as the public telephone network or LAWs (Local Area Networks).

For the communication of a terminal of a first communication network with another, external communication system are usually within the first communication network connection node or. Net transitions installed, eg. B. in the form of gateways or proxies over which the connection between the terminal of the first communication network and the external communication system takes place.

The invention has for its object to provide an efficient method for communication in a communication network, which has connection nodes with connection to an external communication system to show. Furthermore, facilities for carrying out the process will be presented. This object is achieved by a method having the features of claim 1 and by devices having the features of independent claims. Advantageous embodiments and further developments are the subject of dependent claims.

In the method according to the invention for communication in a communication network, the communication network comprises: connection nodes, in each case with connection to an external communication system, as well as communication nodes whose communication with an external communication system takes place via a connection node. Before the communication between a communication node and an external communication system, it is decided via which connection node the communication takes place. According to the invention, the decision is made using a database which is distributed to

Connection node and / or communication node is stored.

In particular, the communication network may be a local area network, such as a corporate network.

Communication network, act. Each connection node of the communication network has a connection to one or more external communication systems. Preferably, the connection nodes are for the sole purpose of establishing the connection between the communication network and an external communication system and do not initiate any communications on their own. A communication node of the communication network can only communicate with a communication partner of an external communication system if the communication is via a connection node. In addition to the connection nodes and the communication nodes, further devices can be part of the communication system.

According to the invention, a database is used which is not stored by a single device but by a plurality of devices which each store a part of the database. Because the storage is not by a single device, but by several institutions, can be spoken by a virtual database. It is possible for further facilities to be involved in the storage of the database in addition to the connection nodes and / or the communication nodes. The database is used in a decision about which connection node is to run a communication between a communication node and an external communication system. This decision is made by the beginning of the communication between the communication node and the external communication system. In this case, it is possible for the database to be taken from a clear result of the decision about the connection node to be used, or for the database to support the decision process insofar as it indicates, for example, a plurality of usable connection nodes.

The invention is particularly applicable to the case that a communication between a communication node and an external communication system is initiated by the communication node, that is, from the point of view of the communication network for outgoing communications such. B. outgoing phone calls.

According to a particularly advantageous embodiment of the invention, the database is a peer-to-peer database, and the storage of the database and access to the database is carried out using a peer-to-peer method. Examples of peer-to-peer methods are: DHT-based methods (DHT: Distributed Hash Table) such as

CHORD, Tapestry, Kademlia, methods derived from DHT-based methods, or other methods such as Gnutella, Opennap, Edonkey, Fasttrack.

In a development of the invention, at least one connection node inputs information about its current state into the database for storage. Preferably all give Connection node or all connection nodes whose access to the database is currently not disturbed, information about their current state in the database. The information about the current state can be, for example, information about an external communication system connected to the connection node, and / or information concerning communication partners of an external communication system reachable via the connection node, such as telephone numbers or parts of external telephone numbers Communication partners. Furthermore, it may be information about costs of communication with an external communication system connected to the connection node, and / or information about available communication resources of the connection node for communication with an external communication system connected to the connection node, and / or information about the type the information transferable via the connection node, such as the indication that voice information and / or IP data can be transmitted via the connection node. Furthermore, the information about the current state may contain information about the coding of the information that can be transmitted via the connection node, and / or information about the location of the connection node. The location of the connection node is particularly advantageous for emergency calls. The reason for this is that especially with emergency calls a local connection node should be selected, since otherwise with choice of an emergency number, in Germany 112 and in the USA 911, under certain circumstances a connection node in a far-flung local area network could be selected and thereby no time near Help delivery would be possible.

In a development of the invention, the at least one connection node updates the information about its current state in the database when it changes its current state. In this way, the content of the database is "up to date", so that the currently valid information Onen queried and an informed decision on the connection node to be used can be made.

According to an advantageous embodiment of the invention, a communication node indicates identification information of a communication partner of an external communication system and then receives from the database the indication of one or more connection nodes via which or which the communication with the communication partner can take place. This means that the communication node queries naming the identification information of its desired communication partner from the database, via which or which connection node can be made a communication with the desired external communication partner.

It is advantageous if, in the case of a plurality of connection nodes via which or which a communication with the desired communication partner can take place, a decision is made between the connection node of the plurality of connection nodes by the database or by the communication node. The communication node can obtain from the database a unique query result regarding the decision between different connection nodes, or an ambiguous result, so that the communication node is responsible for the decision between several usable connection nodes.

With preference, decision rules are stored in the database or in the communication node for the purpose of deciding between the connection nodes of the plurality of connection nodes. The decision rules may, for example, state that the particular connection node should be used for the communication that causes the least cost of communication with the desired external communication partner. The communication network according to the invention has connection nodes, in each case with connection to an external communication system, and communication nodes whose communication with an external communication system takes place via a connection node. According to the invention, it furthermore has a database, which is stored distributed on connection nodes and / or communication nodes, for use in a decision before the communication between a communication node and an external communication system over which connection nodes the communication takes place.

The connection node or communication node according to the invention has means for storing a part of a database, which is stored distributed on connection nodes and / or communication nodes, for use in a decision before the communication between a communication node and an external communication system about which connection node the communication he follows .

The database according to the invention is stored distributed on connection nodes and / or communication nodes, and has means for deciding or participating in a decision prior to the communication between a communication node and an external communication system about which connection nodes the communication takes place.

Both the communication network according to the invention, as well as the connection or communication node according to the invention, as well as the database according to the invention are particularly suitable for carrying out the method according to the invention, and this may also apply to the embodiments and developments. For this they may include other suitable means.

In the following the invention will be explained in more detail with reference to an embodiment. Showing: FIG. 1 shows a section of a corporate communications network;

FIG. 2: a flow diagram of the method according to the invention.

The section from a corporate communications network shown in FIG. 1 comprises the gateways G1, G2, G3 and G4, as well as the terminals USER1, USER2 and USER3. The terminals USER1, USER2 and USER3 may be for example B. to trade stationary or mobile computers, phones or IP phones. The gateways Gl, G2, G3 and G4 enable the terminals USER 1, USER 2 and USER 3 to communicate with other communication systems. For this purpose, the gateways Gl and G2 are connected to the public switched telephone network PSTN (PSTN), the gateway G3 to the Internet INTERNET, and the gateway G4 to another external communication system NET XY. The gateways G1, G2, G3 and G4 can be arbitrarily configured network passages which enable message transmission between the internal company communication network and an external communication system.

Intends z. B. a terminal in the form of a telephone to call another telephone of the public telephone network PSTN, this can be done via the gateway Gl or G2. The connections between the terminals USER 1, USER 2 and USER 3 and the gateways G1, G2, G3 and G4 are not shown for the sake of clarity.

Often, internal connections between the terminals USER 1, USER 2 and USER 3 of the company

Communication network for free possible, for external communications j edoch fall fees. In order to keep these fees low, attempts are made to find the most suitable gateway for the respective target partner of the external communication system. For this purpose, according to the prior art usually with the help of complex criteria decision lists resp. matrices are set up in order to find the best gateway for the respective external destination address. The decision lists resp. matrices are provided by a central facility, e.g. B. PBX: Private Branch Exchange, created and saved. In the desire to establish a connection to an external communication system, a terminal therefore turns to the central facility, which decides which gateway to use and connects the terminal to the respective gateway. Since the costs of different network providers of the external communication systems change frequently, which also makes this very gateway, which makes the most favorable connection possible, the complex assignment tables to the gateways are often subject to complex processing. This administrative effort, which arises through the redefinition of the allocations in the central facility, increases with the size of the corporate communications network and the number of gateways.

According to the invention, there is no central device which is responsible for the assignment of the gateways G1, G2, G3 and G4 to the desired destination addresses of the external communication systems PSTN, INTERNET and NET XY. For this purpose, a peer-to-peer method is used. Peer-to-peer procedures provide instructions for storing data in memory and locating data in the appropriate memory (s). Each peer or a plurality of peers makes a share of its own memory available for storing the peer-to-peer database. The data / information of the peer-to-peer database is typically located at several points of the peer-to-peer network, so that a high reliability of the virtual database formed by distributed peers is achieved. Thus, a peer-to-peer method allows a peer, i. H . a node communicating with other nodes using the peer-to-peer method, finding other peers, whereby a peer-to-peer method is used for addressing the peers. name space is used. Furthermore, a peer is allowed to efficiently find data stored by other peers

There is a virtual database P2P containing the information needed to find a suitable gateway Gl, G2, G3 and G4. The database P2P is not stored by a central facility, but is distributed according to the peer-to-peer method on the gateways Gl, G2, G3 and G4 and the terminals USER 1, USER 2 and USER 3. In this case, it is possible for the storage to be taken over only by the gateways G1, G2, G3 and G4 or only by the terminals USER 1, USER 2 and USER 3, as well as gateways G1, G2, G3 and G4 as well Terminals USER 1, USER 2 and USER 3 are involved in the storage of the database P2P. It is also possible that with respect to the gateways G1, G2, G3 and G4 as well as to the terminals USER 1, USER 2 and USER 3, only a portion of the devices perform memory functions with respect to the database P2P. The storage takes place redundantly, d. H . in the event of a temporary or complete failure of a peer-to-peer servant, i. H . a gateway Gl, G2, G3 and G4 or one of the terminals USER 1, USER 2 and USER 3, the information stored by this is not lost because it is also stored by one or more other peer-to-peer servants. Thus, the peer-to-peer method allows all information of the database P2P can always be found safely and quickly.

Regardless of whether they are involved in the storage of the database P2P, both the gateways Gl, G2, G3 and G4 and the terminals USER 1, USER 2 and USER 3 can access the database P2P, ie. H . Enter or change information in the database P2P and read out or read out information from the database P2P. in each case illustrated by a double arrow in Figure 1 j. As a peer-to-peer method can be used, for example:

• CHORD, described e.g. B. in http: // www. it. biu. ac. il / ~ galk / tGaching / p2p / stoica01chord. pdf,

• Tapestry, described e.g. B. in http: // www. it. ucsb. edu / ~ ravenben / tapestry /

• Kademlia described z. B. in ht tp: // www. it. rice. edu / Conferences / IPTPS02 / 109th pdf • Gnutella described z. B. in http: // www. Stanford. edu / class / cs244b / gnutella_protocol_0 .4. pdf

• Fasttrack (KaZaA, derived from Skype) described z. B. in ht tp: // www. kazaa. com _/ http: // www. skype. com.

The gateways Gl, G2, G3 and G4 provide the following information regarding their condition in the database:

• To which destination addresses can connections be established via the current gateway,

• At what cost are the interim connections offered,

• Which transmission channels resp. which bandwidth is available for the respective gateway, • which data types can be transmitted by the respective gateway and which codecs can be used for the transmissions,

• Location of the gateway.

With regard to the first point, the gateways G1 and G2 of FIG. 1 may be responsible, for example, for certain local area networks, for example the gateway G1 for the Munich area and the gateway G2 for the whole of Germany. The last point, d. H . the location of the gateway proves to be an advantage especially for emergency calls. The information about its state is preferably input by the gateways when booting into the database P2P, so that the respective gateway becomes known as a usable gateway. If the information changes, for example through a time-dependent tariff, which makes the information about the costs time-dependent, or because the available bandwidth is reduced or increased as a result of a newly added or reduced connection, the respective gateway updates the information so that the contents of the database P2P basically indicate the current state of each gateway. Is a gateway, z. B. Due to an error or an overload, this is not detected by the peer-to-peer mechanisms and the information concerning this gateway is deleted.

Each terminal USER 1, USER 2 and USER 3, which can initiate communication with an external communication system, has a P2P part for accessing the database P2P. In the context of the invention, the terminals USER 1, USER 2 and USER 3 use the peer-to-peer method for querying information from the database P2P, no information from the terminals USER 1, USER 2 and USER 3 is stored in entered the database P2P.

FIG. 2 shows the interaction of a gateway G and a terminal USER with the database P2P. Initially, the gateway G in a step OFFER, the above explained information about its current state in the database P2P. If the terminal USER wishes to establish a connection to an external communication system, then in a step SEARCH it requests the destination number or another identification information of the desired communication partner from the database P2P. The peer-to-peer mechanism searches the entire communication network for one or more gateways over which the desired connection can be established. In a RESULT step, that receives Terminal USER the result of the query from the database P2P. The result may consist of specifying one or more gateways over which the connection to the desired communication partner can take place. If the query result contains, for example, only the gateway G, then the terminal USER establishes the connection to the gateway G in a step CONNECT.

In addition to the information described above, which describe the current state of the gateways, further information can be stored in the database P2P for storage, such. B. Decision parameters and rules that allow the decision between different gateways that can connect to the same communication partner of an external communication system. A decision parameter may be, in particular, the

Cost of the current connection act. In this way, it is possible for a terminal to receive as query result only that particular gateway which, taking into account the decision parameters and rules stored in the database P2P, is the most advantageous, or the most advantageous. if equal, a list of these gateways.

The following possibilities exist for dealing with several alternative network passes: • The decision is made by the database P2P, the necessary decision parameters and rules are stored in the database P2P. In this case, the terminal enters the identification information of the desired communication partner and as a result obtains a gateway or, if the decision parameters and rules do not allow a decision between multiple gateways, multiple gateways. If the decision parameters and rules are stored in the database P2P, this has the advantage that the same criteria for the selection of a gateway apply throughout the network.

• The decision is made by the terminal, the necessary decision parameters and rules are stored in the terminal. In this case, the terminal enters the identification information of the desired communication partner and, as a result, obtains all the gateways which can establish the connection desired by the terminal between which the terminal decides using the decision parameters and rules. • The decision is made by the database P2P and by the terminal, decision parameters and rules are stored both in the database P2P and in the terminal. In this case, the terminal enters the identification information of the desired communication partner and as a result obtains one or more gateways which represent a preselection by the database P2P, between which it decides further.

Receiving a terminal as a query result multiple possible gateways from the database P2P, and it selects from several possible gateways gateway, which is no longer available due to a sudden error, another of the multiple gateways can be used without a renewed query must be done.

In the decision parameters, it may be in addition to the costs already mentioned z. B. The point is that only voice should be transmitted, that a single channel is sufficient, that the codec G 7.11 should be used, that the gateway with the fastest response time should be selected, or that an IP gateway should be used. The decision rules can relate to the priority of individual decision parameters. B. Costs have the highest priority, followed by the available bandwidth.

Furthermore, it is possible for the terminal to make the decision between a plurality of possible gateways, which extracts decision parameters and rules for decision-making, however, from the database P2P. This decision Divorce parameters and rules can be retrieved from a terminal at its startup from the database P2P, or, for example, in the SEARCH step of FIG. 2. Furthermore, it is possible for a terminal to automatically change upon a change in the decision parameters and rules stored in the database P2P so that the terminal does not have to query the decision parameters and rules on its own.

Compared with the alternative solution of using a database stored in a central facility which can be contacted by all terminals, the inventive method has the advantage of better scalability, since the storage possibilities of a central facility are generally more limited than the storage capabilities of a central facility database stored on a variety of devices. Furthermore, the availability of the distributed database is greater and thus the probability of failure is lower, since if the central device fails, the entire network is affected, while if one device that stores a part of the distributed database fails, the use of the distributed database due to the redundant peer to-peer storage method is not limited. Finally, the use of the distributed database according to the peer-to-peer method enables the timely consideration of changes in the state of gateways. This dynamic behavior of the distributed database is not achievable with a centrally managed database.

Claims

claims 1. A method of communication in a communication network, wherein • the communication network comprises: Connection nodes (G1, G2, G3, G4) in each case with connection to an external communication system (PSTN, INTERNET, NET XY), and Communication node (USER 1, USER 2, USER 3) whose communication with an external communication system (PSTN, INTERNET, NET XY) via a connection node (G1, G2, G3, G4), Before communication between a communication node (USER 1, USER 2, USER 3) and an external communication system (PSTN, INTERNET, NET XY) it is decided via which connection nodes (G1, G2, G3, G4) the communication takes place, characterized, That the decision is made using a database (P2P) _r which is distributed to connection nodes (G1, G2, G3, G4) and / or communication nodes (USER 1, USER 2, USER 3). 2. The method according to claim 1, characterized in that the database (P2P) is a peer-to-peer database, and the storage of the database (P2P) and the access to the database (P2P) using a Peer-to-peer procedure. 3. The method according to claim 1 or 2, characterized in that at least one connection node (G1, G2, G3, G4) enters information about its current state in the database (P2P) for storage. 4. The method according to claim 3, characterized in that the information about the current state comprises: information about an attached to the connection node (G1, G2, G3, G4) external communication system (PSTN, INTERNET, NET XY), and / or Information relating to the connection node (G1, G2, G3, G4) reachable communication partner of an external communication system (PSTN, INTERNET, NET XY), and / or Information about costs of communication with an external communication system (PSTN, INTERNET, NET XY) connected to the connection node (G1, G2, G3, G4), and / or Information about available communication resources of the connection node for communication with an external communication system (PSTN, INTERNET, NET XY) connected to the connection node (G1, G2, G3, G4), and / or Information about the type of information that can be transmitted via the connection nodes (G1, G2, G3, G4), and / or Information about the coding of the information transferable via the connection nodes (G1, G2, G3, G4), and / or • Information about the location of the connection node. 5. The method according to claim 3 or 4, characterized in that the at least one connection node (G1, G2, G3, G4) updates the information about its current state in the database (P2P) when it changes its current state. 6. The method according to any one of claims 1 to 5, characterized in that a communication node (USER 1, USER 2, USER 3) identification information of a communication partner of an external communication system (PSTN, INTERNET, NET XY) indicates and then from the database (P2P) the indication of one or more connection nodes over which or which the communication with the communication partner can take place receives. 7. The method according to claim 6, characterized in that, in the case of a plurality of connection nodes via which or which the communication with the communication partner can take place, a decision is made between the connection nodes (G1, G2, G3, G4) of the plurality of connection nodes ( Gl, G2, G3, G4) through the database (P2P) or through the communication node (USER 1, USER 2, USER 3). 8. The method according to claim 7, characterized in that in the database (P2P) and / or in the communication node (USER 1, USER 2, USER 3) decision rules are stored for the decision between the connection nodes (Gl, G2, G3, G4) the plurality of connection nodes. 9. communication network, comprising: connection nodes (G1, G2, G3, G4) in each case with connection to an external communication system (PSTN, INTERNET, NET XY), and Communication nodes whose communication with an external communication system (PSTN, INTERNET, NET XY) takes place via a connection node (G1, G2, G3, G4), characterized by a database (P2P) distributed over connection nodes (G1, G2, G3, G4) and / or communication node (USER 1, USER 2, USER 3) is stored, for use in a decision prior to communication between a communication node (USER 1, USER 2, USER 3) and a external communication system (PSTN, INTERNET, NET XY) about which connection nodes (G1, G2, G3, G4) the communication takes place. 10. Connection nodes (G1, G2, G3, G4) or communication nodes (USER 1, USER 2, USER 3) for a communication network, which connection nodes (G1, G2, G3, G4) are in each case connected to an external communication system ( PSTN, INTERNET, NET XY), and communication nodes whose communication with an external communication system (PSTN, INTERNET, NET XY) takes place via a connection node (G1, G2, G3, G4), characterized by Means for storing a portion of a database (P2P) stored distributed on connection nodes (G1, G2, G3, G4) and / or communication nodes (USER1, USER2, USER3) for use in a decision prior to communication between a communication node (USER 1, USER 2, USER 3) and an external communication system (PSTN, INTERNET, NET XY) about which connection nodes (G1, G2, G3, G4) the communication takes place. 11. Database (P2P) for a communication network, which connection nodes (G1, G2, G3, G4) in each case with connection to an external communication system (PSTN, INTERNET, NET XY), and communication nodes whose communication with an external communication system (PSTN, INTERNET, NET XY) via a connection node (G1, G2, G3, G4), which is distributed to connection nodes (G1, G2, G3, G4) and / or communication nodes (USER 1, USER 2, USER 3) . marked by Means for deciding or participating in a decision prior to communication between a communication node (USER 1, USER 2, USER 3) and an external communication system (PSTN, INTERNET, NET XY) about which connection nodes (G1, G2, G3, G4 ) the communication takes place.