DE4441356C2 - Method for routing connections in an intermediary communication network - Google Patents

Description

The invention relates to a method for routing connections conditions in a mediating communication network according to Preamble of claim 1 (DE 12 95 668 C2).

The establishment and management of communication networks high investments and expenses. It is therefore necessary these high costs due to the highest possible utilization of the To justify communication network. Such a high Utilization, however, brings with it the usual communication cation networks such as telephone networks at times are overloaded and connections cannot be established. This Overloads can be caused by "intelligent" connection establishment be avoided, d. H. that at a given time Connections to be made as evenly as possible over the whole network can be distributed.

This division is done with so-called dynamic Routing method. In an internally known method of this type, in Intervals of about 10 seconds status information about the Network sent to a central computer. In dependence of the load on the network is then a single call, whose direct connection between an originating switching node, to which the calling subscriber is connected and a destination switching node to which the called subscriber is connected is due to an overload of the transmission path between  the two switching nodes is not possible through this central computer via at least one other exchange knots optimally routed. This process is very complex and therefore only suitable for smaller networks.

Another internally known procedure is not directly aimed at everyone transferable call a query over a signaling network at the destination switching node, which transmission routes its view is low and therefore cheap for the call are. The originating node receives this information and then selects an intermediary node that both to the originating switching node as well as to the target switching node has a transmission link with low occupancy.

With this method, there is a connection with every routing attempt between the routing computer and the destination ver averaging node and the originating switching node of the Network is necessary, the procedure is therefore also very complex.

Other internally known methods update the network states in larger intervals, for example hourly, they are there less expensive, but deliver because of the large Aktua Interval less good results.

The object of the invention is a routing method specify where good results with little effort too can be achieved with large communication networks.

This is done according to the invention with a method according to An saying 1.

The method according to the invention enables the update the information about the network states in particularly low  Intervals z. B. 10 seconds, with little effort. In order to it is possible to switch even larger networks up to about 1000 equip nodes with dynamic routing, more than with their known methods. In addition, the fiction appropriate procedures with little effort to existing communica tion networks are adapted.

According to claim 2, the invention Process can be realized particularly cheap.

In the case of larger networks, an embodiment of the invention is according to Claim 3 or claim 4 advantageous because of several Routing processors the reliability is increased and the use of a satellite as known per se from EP-A2-0563572 is the cost of the connection between the Routing processors and the communication network reduced.

An embodiment of the invention is also advantageous A method according to claim 5, which the optimization of Routing process with regard to the cost-benefit ratio of calls enables. For example, a call is not put through, if the probability is very high that through this Routing decision blocked one or more other calls would be, and the resulting failure higher Cost caused by blocking the subject call is the case.

Favorable implementation variants of the method according to claim 5 are described by claims 6 and 7.

The invention is explained in more detail with reference to a figure, which at playfully shows a communication network.

The figure shows a communication network, which switching contains nodes K1, K2, K3, K4, which are connected by transmission paths U1,  U2, U3, U4, U5, U6 are connected to each other. In addition are two routing processors RP1, RP2 and a routing management pro processor RMP provided. The connection between the Ver averaging node K1, K2, K3, K4, the routing processors RP1, RP2 and the routing management processor RMP will have one S1 produced. Part of the communication network TN1, TN2 connected.

A connection setup between an originating subscriber TN1 and a destination subscriber TN2 proceeds as follows:
First, it is checked whether the direct route between the two subscribers TN1, TN2 is available via the first switching node K1, the fifth transmission path US and the second switching node K2. If this is the case, the connection is established. The two routing processors are not affected.

However, if the specified direct connection is not available is because the fifth transmission path US is overloaded, or but is also unable to function due to a technical effect, then the first switching node K1 starts routing demand on the first person responsible in this case Routing processor RP1 sent. The connection of the Routing processors RP1, RP2 with the switching nodes K1, K2, K3, K4 takes place via a signal i, not shown in the figure network. The organization of the signaling network ent speaks the so-called "common channel signaling" protocol No. 7 by CCITT.

Due to the requirement and the data available on the The utilization of the entire communication network decides responsible routing processor RP1 which alternative routes for the connection come into question. In the present case, this can via the third switching node K3 and the first  Transmission path U1 and the third transmission path U3 happen, or alternatively via the fourth switching node K4 and the second and fourth transmission path U1, U2. The choice between these two possible routes are now based on the Be burden on the transmission routes of these routes. If, for example se is certain that the first transmission path U1 is already completely is busy, then the connection variant via the fourth switching node K4 selected.

The connections are made so that the network is possible load as soon as possible, and no load peaks at one individual transmission paths occur.

The information about the current utilization of the individual Transmission paths U1, U2, U3, U4, U5, U6 now generate the Routing processors RP1, RP2 themselves as part of their Routing tasks. Each routing request is associated with it Data on the affected, i.e. H. blocked transmission path in the in the present case the fifth transmission path US is saved and from the frequency of these routing requests and thus ver bound block notifications, the computer calculates the current All utilization of the respective transmission path. There is no such thing own mediation process between the mediation nodes K1, K2, K3, K4 and the routing processors RP1 and RP2 necessary dig., but this happens in the context of the accruing Routing tasks.

With the routing method described, one is already clear improvement of the possible utilization of a communica network achieved. A further optimization can be done by the Use a routing management processor RMP. The It calculates from the so-called destination traffic data of the municipality network, for example, hourly forecasts for the future utilization of the network and the individual transmission routes U1, U2, U3, U4, U5, U6.  

The target traffic data relate to the information which participants communicated with each other and how often during the period under review. On the basis of this data, the probability of the transmission paths being occupied is calculated in the routing management processor. In the present example, this is done with the help of a so-called "forward looking routing" algorithm as described in KR Krishnan, TJ Ott: Forward looking routing:
A New State-Dependent Routing Scheme, Teletraffic Science for New Cost-Effective Systems, Networks and Services, ITC-12 (1989).

Following this algorithm are in the routing management processor Evaluation tables for the individual transmission paths U1, U2, U3, U4, U5, U6 determined by which the routing processors RP1, RP2 can check the intended transmission paths, whether it is with regard to the forecast utilization for the valid period are to be regarded as favorable. So it can e.g. B. happen that after the forecast utilization of the over transmission paths U1, U2, U3, U4, U5, U6 the throughput of a Connection would be disadvantageous because it would make two other connections would be blocked. So this connection is not established, the network is with the two possible and statistical other connections taking place are better utilized and works cheaper.

The. Connection between routing management processor RMP den Routing processors RP1, RP2 and the switching nodes K1, K2, K3, K4 takes place via a second data transmission network, which is in the picture is not shown and is realized by means of satellite S1.

The use of one or more satellites is special advantageous for communication networks that are geographically large Affect areas, this is particularly the case with telephone networks in sparsely populated areas or, for example, by telephone nets for island groups, or for very large ones Communication networks with many switching nodes.  

In this case, the high costs for a large data transmission network be avoided.

The invention is particularly suitable for Use in telephone networks. But it can also be advantageous with similarly structured communication networks and for example can also be used in traffic management systems.

Claims (7)

1. Method for routing connections in a mediating communication network which contains switching nodes (K1, K2, K3, K4) which are connected to one another by transmission paths (U1, U2, U3, U4, U5, U6), in the event of a blockage a direct transmission path (U1, U2, U3, U4, U5, U6) between two switching nodes (K1, K2, K3, K4) of the communication network, one of the switching nodes concerned generates a request to determine an alternative route and then, based on the occupancy status of the possible transmission routes (U1, U2, U3, U4, U5, U6) the alternative route is determined, characterized in that in the course of determining the alternative routes, each request for determining an alternative route together with the data about the blocked transmission route concerned (U1, U2, U3, U4, U5, U6) is saved and from the frequency of the requests and the data on the transmission paths concerned (U1, U2, U3, U4, U5, U6) of the Bele condition of the transmission paths (U1, U2, U3, U4, U5, U6) of the communication network is determined. 2. The method according to claim 1, characterized in that at least a routing processor (RP1, RP2) is used, which has a Signaling network with the switching nodes (K1, K2, K3, K4) connected is. 3. The method according to claim 2, characterized records that several routing processors (RP1, RP2) are used with each other through a first data transmission network who are connected. 4. The method according to claim 3, characterized records that in itself at the first data transmission network known way, a satellite (S1) is used.   5. The method according to claim 1, characterized records that in addition measurements of the target traffic be carried out and with regard to the determined Probability of blocking future connection requests the determination of the alternative route is optimized. 6. The method according to claim 5, characterized in that in addition to communication network and at least one routing processor (RP1, RP2) uses a routing management processor (RMP) is that with a via a second data transmission network at least one routing processor (RP1, RP2) and the mediator tion nodes (K1, K2, K3, K4) connected to the communication network is. 7. The method according to claim 6, characterized indicates that in the second data transmission network in a satellite (S1) is known to have died.