Abstract:
A telecommunications system, method of managing a telecommunications system and program product therefore. Telecommunications system branches are linked to a network and to each other in a wide area network (WAN). Each branch includes telecommunications devices and a media processor that supports a concurrent port for each local telecommunications device. A controller, e.g., at a data center, selects media processing resources to aggregate system media during conference calls for efficient bandwidth use. The controller may select resources based on user location, Call Admission Control (CAC) policy bandwidth usage, and availability of media resources and media processor ports.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention is related to packet based telecommunications such as Voice over Internet Protocol (VoIP) communications and more particularly, to controlling packet based telecommunications networks for multiparty calls such as VoIP conference calls. 
     2. Background Description 
     Since Voice over Internet Protocol (VoIP) communications use a connectionless protocol, as long as Quality of Service (QoS) is not a factor, any number of calls may be carried over a packet based network link. However, because bandwidth is not unlimited, QoS is almost always a consideration. Limited bandwidth has required constraining link traffic to insure high QoS. In particular, in a connectionless protocol telecommunications system conducting too many calls over a broadband link can cause gaps, delays and dropped calls. Consequently, packet networks restrict the number of active calls to protect voice traffic from the negative effects of other voice traffic and to prevent excess voice traffic. 
     Currently, for example, Call Admission Control (CAC) is used in packet based telecommunications, such as VoIP, to control and ensure adequate bandwidth for the authorized communications flows. Typically, CAC policies are implemented to ensure that calls cannot setup whenever current traffic is consuming enough of the available broadband or wide area network (WAN) bandwidth to make it impossible to support added flow without negatively affecting the QoS for existing voice traffic. 
     Typically, these CAC policies treat all calls the same. Conference calls that may originate from multiple network endpoints, traverse the Internet, for example, connecting to another, remote network branch with multiple participating network endpoints. Assigning each participant as an individual call is inefficient and may, very likely and very quickly, consume most or all available resources. One party, e.g., initiating the conference, cannot select the media processor for the conference call with other participants remote to the originator. Further, typical state of the art call management servers that provide conference services to a large number of locations are constrained by CAC policies for any location remote to the single selected media processor. This frequently results in otherwise available WAN link bandwidth, e.g., in branches other than the branch where the selected media processor resides, being unused and unusable. 
     Thus, there is a need for packet telecommunications networks that improve bandwidth usage on WAN links for optimal network capacity consumption to expand the number of allowable conference calls and call participants for a given WAN link bandwidth. 
     SUMMARY OF THE INVENTION 
     It is a purpose of the invention to optimize bandwidth usage during conference calls in telecommunications systems; 
     It is another purpose of the invention to increase conference call capacity in telecommunications systems; 
     It is yet another purpose of the invention to improve real time media usage management for telecommunications networks with bandwidth that is limited between branch offices. 
     The present invention relates to a telecommunications system, method of managing a telecommunications system for optimized bandwidth usage during conference calls and program product therefor. Telecommunications system branches are linked to a network, e.g., the Internet, and to each other in a wide area network (WAN). Each branch includes telecommunications devices and a media processor that supports a concurrent port for each local telecommunications device. A controller, e.g., at a data center, selects media processing resources to aggregate system media during conference calls for efficient bandwidth use. The controller may select resources based on user location, Call Admission Control (CAC) policy bandwidth usage, and availability of media resources and media processor ports. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and other objects, aspects and advantages will be better understood from the following detailed description of a preferred embodiment of the invention with reference to the drawings, in which: 
         FIG. 1  shows an example of an enterprise with a star shaped network according to a preferred embodiment of the present invention; 
         FIGS. 2A-B  show a simple example of a first conference setup and assignment table for a conference involving 2 parties from branch A, 4 parties from branch B, and 2 parties from branch C; 
         FIGS. 3A-B  show an example of a second conference setup and assignment table for a second conference on the same system; 
         FIGS. 4A-B  show yet another example, wherein a second conference is established between branches B and C, even though Branch B is fully booked. 
     
    
    
     DESCRIPTION OF PREFERRED EMBODIMENTS 
     Turning now to the drawings and more particularly,  FIG. 1  shows an example of an enterprise with a star shaped network  100  according to a preferred embodiment of the present invention. The star shaped network  100  in this example includes 3 branches  102 ,  104 ,  106 , also labeled A, B and C. Each branch  102 ,  104 ,  106  has multiple (6 in this example) endpoints  102 - 2 — 102 - 12 ,  104 - 2 — 104 - 12 ,  106 - 2 — 106 - 12 , and a media processor  108 ,  110 ,  112 . Each media processor  108 ,  110 ,  112  supports 6 concurrent ports. Each branch  102 ,  104 ,  106  has a bandwidth limited WAN link  114 ,  116 ,  118  to a network  120 , e.g., the Internet or any suitable network, with a CAC policy that allows two media streams. A controller  122 , e.g., located in a data center, selects media processing resources for the entire network  100  to aggregate media for efficient bandwidth usage on WAN links  114 ,  116 ,  118 , according to a preferred embodiment of the present invention. It should be noted that the star topology of the network  100  in this example is for example only and not intended as a limitation. The present invention has application to any suitable network topology, including tree and mesh topologies or any combination thereof. 
     In particular, upon initiating a conference call, e.g., receiving a request for a conference call, a preferred controller  122  proceeds with media processing resource selection for the enterprise  100 , selecting resources for conference media processors  108 ,  110 ,  112  based on user location, CAC policy bandwidth usage, and availability of media resources and media processor ports. Each CAC policy sets the number of concurrent media streams that are allowed over the WAN links  114 ,  116 ,  118 , depending upon link bandwidth. Ports on media processors  108 ,  110 ,  112  may be reallocated as parties are added or removed from conference calls, e.g., using standard media gateway control protocols. Typical such standard gateway control protocols include, for example, Media Gateway Control Protocol (MGCP), media gateway control (megaco) and Session Initiation Protocol (SIP) with Minimal XML/Media Objects Markup Language (MXML/MOML). Further, the controller  122  provides media re-negotiation towards the conference parties using, for example, SIP/Session Description Protocol (SIP/SDP). Thus, even when conference activity on one branch (e.g.,  104 ) uses all available Call Admission Control (CAC) resources and occupies all available bandwidth for that branch  104 , the controller  122  can establish other independent conference calls, e.g., between other of branches  102 ,  106 . 
       FIGS. 2A-B  show a simple example of a first conference setup by the controller  122  and a corresponding assignment table with like features labeled identically. In this example, the conference involves 2 parties  102 - 4  and  102 - 8  from branch A, 4 parties  104 - 4 ,  104 - 6 ,  104 - 8 , and  104 - 10  from branch B, and 2 parties  106 - 2  and  106 - 4  from branch C. The controller  122  allocates resources for the media processors or servers  108 ,  110 ,  112  to minimize media streams  130 ,  132  based on user location, CAC policies, and availability of media processor ports as indicated hereinabove. 
     In particular, the CAC policies define resource thresholds for each link. This resource threshold may be expressed in terms of bandwidth or simply, as a number of concurrent calls. In this simple example, the controller  122 , treats each media stream  130 ,  132  as consuming the same bandwidth. Usage also may be described within the same unit. Although in Branch  102 , for example, the CAC policy permits 2 media streams or call legs across the WAN, the usage in  FIG. 2A  is 1 call leg, media streams  130 . Preferably, however, the controller  122  is aware of the media negotiations for each call, and uses a more sophisticated calculation based on consumed bandwidth; the sum of the bandwidth that the media streams  130 ,  132  actually consume in branch  104 , for example. 
     Assignment table  134  of  FIG. 2B  shows the assignment of concurrent calls per CAC policy and Media Processing (MP) resources, comparing available with used for this example. In the first branch  102  at the WAN link  114  one of two available concurrent calls for the CAC Policy is used for three of the six media processor  108  ports (to  102 - 4 ,  102 - 8  and media processor  110 ). In the second branch  104  at WAN link  116  both of the available concurrent calls for the CAC Policy are used for all six of the six media processor  110  ports (to  104 - 4 ,  104 - 6 ,  104 - 8 ,  104 - 10  and media processors  108 ,  112 ). Likewise, in the third branch  106  at WAN link  118  one of two available concurrent calls for the CAC Policy is used for three of the six media processor  112  ports (to  106 - 2 ,  106 - 4  and media processor  110 ). So as can be seen from this simple example, WAN resource usage is assigned to optimize media processing resources distributed within each CAC policy, leaving resources available at branches  102  and  106  for other calls or conference calls, for example. 
       FIGS. 3A-B  show an example of a second conference setup by the controller  122  in response to a subsequent request and a corresponding assignment table for the second conference on the same system  100  with like features labeled identically. This second conference involves 2 different parties  102 - 6  and  102 - 10  from branch A and 2 different parties  106 - 6  and  106 - 12  from branch C. The controller  122  allocates remaining resources for media servers  108  and  112  to media stream  136 , again treating each media stream  130 ,  132  and  136  as consuming the same bandwidth. This establishes the second conference. The updated assignment table  138  reflects all CAC policies and MP resources being used. 
       FIGS. 4A-B  show yet another example, wherein a second conference is established between branches B and C by the controller  122  in response to a subsequent request and with like features labeled identically. In this example, the second conference is established even though Branch B is fully booked, i.e., all CAC policies and MP resources are in use. The second conference has 1 party from Branch B, and 2 parties from Branch C. In this example, each of branches B and C is connected to an external network  140 , e.g., a publicly switched telephone network (PSTN), through a local gateway  142 ,  144 . Preferably, although not shown in this example, each branch has a local gateway to an external network or some other path to connecting to other branches. Continuing this example, branch B endpoint  104 - 2  is directly connected to the local gateway  142 . Branch C endpoints  106 - 6  and  106 - 12  connect through the media processor  112  to the local gateway  144 . The corresponding assignment table  146  reflects that CAC policies and MP resources are assigned for branches A and B as in the single conference call example of  FIGS. 2A-B . However, the assignment table  146  reflects that Branch C has only one CAC policy in use, but all MP resources are being used. 
     Advantageously, the present invention distributes media processing resources for conferencing in telecommunications networks otherwise constrained by limited bandwidth links. Resources are distributed based on user location, link bandwidth and CAC policies. In particular, the present invention optimizes resources in systems serving any geographically distributed organization that may rely on real time conferencing to conduct business. Conference media processor resources are deployed based on CAC policies; Conference media processor resources are selected for the network based on: user location, bandwidth usage per CAC policy, available/free media resources per media processor. 
     A preferred call management server controls conference calling to provide optimized conference services to a large number of locations that could not be controlled by a single media processor. Conference participants may be added in excess of defined CAC policies, aggregating media (e.g., local media processing) for more efficient WAN link bandwidth usage. Conference media processors and processor resources may be selected based on the party initiating the conference, even with other participants in locations remote to the conference originator. 
     While the invention has been described in terms of preferred embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the appended claims. It is intended that all such variations and modifications fall within the scope of the appended claims. Examples and drawings are, accordingly, to be regarded as illustrative rather than restrictive.