Classifications

• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M7/00—Arrangements for interconnection between switching centres
  • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
  • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/10—Architectures or entities
  • H04L65/102—Gateways
  • H04L65/1043—Gateway controllers, e.g. media gateway control protocol [MGCP] controllers
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/1066—Session management
  • H04L65/1069—Session establishment or de-establishment
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/1066—Session management
  • H04L65/1101—Session protocols
  • H04L65/1104—Session initiation protocol [SIP]
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
  • H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
  • H04L65/80—Responding to QoS
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M7/00—Arrangements for interconnection between switching centres
  • H04M7/0024—Services and arrangements where telephone services are combined with data services
  • H04M7/0057—Services where the data services network provides a telephone service in addition or as an alternative, e.g. for backup purposes, to the telephone service provided by the telephone services network
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M7/00—Arrangements for interconnection between switching centres
  • H04M7/12—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal
  • H04M7/1205—Arrangements for interconnection between switching centres for working between exchanges having different types of switching equipment, e.g. power-driven and step by step or decimal and non-decimal where the types of switching equipement comprises PSTN/ISDN equipment and switching equipment of networks other than PSTN/ISDN, e.g. Internet Protocol networks
  • H04M7/1285—Details of finding and selecting a gateway for a particular call
• • H—ELECTRICITY
  • H04—ELECTRIC COMMUNICATION TECHNIQUE
  • H04M—TELEPHONIC COMMUNICATION
  • H04M3/00—Automatic or semi-automatic exchanges
  • H04M3/42—Systems providing special services or facilities to subscribers
  • H04M3/4228—Systems providing special services or facilities to subscribers in networks
  • H04M3/42289—Systems providing special services or facilities to subscribers in networks with carrierprovider selection by subscriber

Definitions

• the present invention relates to a method for routing a call in a telecommunications network and a switch for a telecommu ⁇ nications network. More particularly, the present invention relates to a method and telecoms switch for facilitating op- timized resource allocation to calls.
• Modern communications networks generally carry two types of traffic or data.
• the first is the traffic which is transmit ⁇ ted by or delivered to a user or subscriber, and which is usually paid for by the user. That type of traffic is widely known as user traffic or subscriber traffic and usually con ⁇ veyed by means of so called bearer connections, or bearers.
• the second is the traffic caused by network management appli ⁇ cations in sending and receiving management data from network elements, known as management traffic.
• the management traffic is also known as signaling traffic.
• signaling traffic refers to the ex ⁇ change of signaling messages between various network elements such as database servers, local exchanges, transit exchanges, and user terminals.
• NTN Next Generation Networks
• both the signal ⁇ ing connection (s) and the bearer connection (s) between two pieces of network equipment may comprise more than one dis ⁇ tinct path.
• the bearer for example, can be routed over dif- ferent paths.
• a user dialed number or other (destination) address infor ⁇ mation normally influences the routing of a call and therefore the selection of a path. Said routing methods however fail to optimally utilize net ⁇ work and/or switch resources in modern networks providing a wide range of voice, data and video services.
• a method for routing a call in a telecommu ⁇ nications network comprising the steps of:
• the invention also provides a switch for a telecommunications network having a switching logic for executing the inventive method.
• Fig. 1 shows in the form of a flow diagram one embodiment of the inventive method
• Fig. 2 shows an exemplary network configuration wherein the invention may be deployed
• Fig. 3 shows in the form of a flow diagram the steps for con ⁇ figuring a switch of a telecommunications network; and Fig. 4 shows in the form of a flow diagram another embodiment of the inventive method.
• a destination of a call is de- termined. Such determination may be based, for example, on address information 14 contained in call messages such as call setup messages. This address information may, in turn, be provided by a calling user (not shown) trying to set up a connection to a called user.
• step 16 at least two routes, or paths, towards the desti ⁇ nation are determined.
• the result of step 16 may be available routes, i.e., routes that are neither congested nor otherwise unavailable.
• the number of possible routes which may be large in certain configurations, may be limited to allow for a speedier proc ⁇ essing of the results of step 16.
• route capabilities are determined for each route that was determined in step 16.
• Route capabilities may include items such as: available bandwidth, available codecs for audio and/or video and/or "pure" data transmission, line and/or service quality, etc.
• step 20 the route capabilities determined in step 18 are matched, for each route, with the requirements of the call to be routed.
• the result of matching step 20 is a set of routes able to accommodate the call to be routed.
• a ba ⁇ sic audio call can be conveyed using any of the following routes: a route having basic audio capabilities, a route hav ⁇ ing advanced audio capabilities, and a route having audio and video capabilities.
• a video call can only be conveyed on the route having video capabilities.
• the outcome of step 20 will be all three routes for the basic au- dio call and only the video enabled route for the video call.
• step 22 there will be selected among the routes determined by matching step 20 the least expensive route that can accommodate the call.
• the "cost", or resource value, as ⁇ sociated with a route may depend on several factors. Codecs, for example, may have a large impact on the cost incurred by routing a call. Expensive, or valuable, codecs may include video codecs or advanced audio codecs such as G.723 or G.729. Inexpensive codecs include, for example, audio codecs such as G.711, a codec traditionally used in voice encoding over PSTN-type telecommunications networks.
• the cost caused by a codec may be influenced by licensing fees for using the codec (usually charged per port supporting the codec) , and hardware requirements to support the codec (advanced video codecs, for example, require a large quantity of computing power in order to operate in real-time) .
• the invention achieves an optimal usage of network resources, which will be illustrated in the following preferred embodi ⁇ ment of the invention.
• a given gateway of the network may support a video codec and an audio codec at the same time and to the same destination.
• a pure audio call to that same destination may occupy the sys- tern resource, which is capable of video too.
• system resources are wasted because the expen ⁇ sive video codec is seized for an inexpensive (and low- revenue) audio call.
• This may also be true for a pure audio call: for example a G.711 to G.711 call (inexpensive codec) and a G.723 to G.711 call (expensive codec) are two different calls with regards to system resource usage.
• the switching logic routes the call codec dependent.
• the codecs are not equally expensive. There ⁇ fore, codec dependent routing provides for more cost-effi- cient routing by including codec properties in the routing process. Codec-dependent routing also provides for a better resource management.
• the call requirements may be determined from the calling user's invoked services and not, as had been previ ⁇ ously suggested, by the user dialing different numbers or otherwise providing an explicit gateway selecting address.
• the user may dial the same number to a given desti- nation but may activate different services for each call to that destination.
• the switching resources in that gateway are optimally used because inexpensive calls are routed differ ⁇ ently along routes where these calls do not seize expensive resources .
• FIG. 2 there is shown an exemplary network configuration 100 illustrating the application of the inventive method in a telecommunications network.
• an IP based network section 101 for example a SIP network, is connected via gateways 103, 104 to a TDM network section 110.
• an ex ⁇ emplary terminal equipment 105 having the capability to com ⁇ municate using a multitude of audio codecs, including the GSM codes.
• a call setup message such as a SIP INVITE message, or any other call message, will give an indication of all codecs available at terminal 105 for a given call. Such indication will be received by a soft switch 102 controlling the call.
• First gateway 103 may be a low-end (and inexpensive) gateway capable of GSM co ⁇ dec transcoding
• second gateway 104 may be a high-end (and expensive) gateway capable of handling a vast variety of codecs such as G.723, GSM, ⁇ -law PCM, A-law PCM, G.726, ADPCM, SLIN, LPClO, G.729, SPEEX, iLBC.
• Each of the routes 106, 107 is capable of connecting an audio call from IP ter ⁇ minal 105 to TDM terminal 113.
• soft switch 102 chooses the least expensive available route for completing a call setup from IP terminal 105, in the example of fig. 2 by choosing route 106 via first gateway 103, as IP terminal 105 supports the GSM codec which is also supported by less expensive gate ⁇ way 103.
• soft switch 102 will choose route 107 via second gateway 104 to connect such VoIP terminal to destination terminal 113, employing the more expensive resource in the absence of an alternative, less expensive, route.
• each route 106, 107 via gateway 103, 104 to a given destination e.g. the TDM network 110
• a given destination e.g. the TDM network 110
• This procedure may be repeated for each gateway available to a given destina ⁇ tion.
• Protocol means may be provided for a soft switch to automatically detect gateways to a given destination and de ⁇ termine the gateway and/or codec properties and cost.
• fig. 4 shows in the form of a flow diagram another embodiment of the inventive method, preferably employed by a soft switch 102 for selecting a route towards a destination.
• step 301 all available, regular routes are determined.
• step 302 it will be determined if multiple routes towards the destination exist. If not, the method exits by selecting the only route for conveying the call information in step 306. Otherwise the method continues by determining in step 303 one of the available routes is marked "preferred route". If this is the case, method exits by selecting the preferred route for conveying the call information in step 307. Other ⁇ wise all available routes are assigned a value which is de- rived from the codec or gateway values available at each route's gateway in step 304.
• step 305 the least expensive route is selected by comparing the route's values as assigned in step 304 and selecting the route having the lowest value representing the least cost.

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• Engineering & Computer Science (AREA)
• Signal Processing (AREA)
• Computer Networks & Wireless Communication (AREA)
• Multimedia (AREA)
• Business, Economics & Management (AREA)
• General Business, Economics & Management (AREA)
• General Engineering & Computer Science (AREA)
• Telephonic Communication Services (AREA)
• Data Exchanges In Wide-Area Networks (AREA)

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• 2005
  • 2005-10-07 EP EP05801552A patent/EP1800453A1/de not_active Withdrawn
  • 2005-10-07 WO PCT/EP2005/055088 patent/WO2006040299A1/en active Application Filing

Non-Patent Citations (1)

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