Patent Publication Number: US-7715366-B1

Title: User based message prioritization

Description:
RELATED APPLICATIONS 
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     FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
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     MICROFICHE APPENDIX 
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     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is related to packet network technologies, and in particular, to methods and systems for user based prioritized message processing. 
     2. Description of the Prior Art 
     Packet based voice communication networks package and transmit voice communications based on packet protocols. Voice over Internet Protocol (VoIP) networks typify modern packet based voice communication networks. VoIP networks digitize, compress, and convert voice communications to interne protocol (IP) packets. Specialized signaling protocols are then employed to setup and tear down VoIP calls. Specialized signaling is also utilized to locate users across the various VoIP networks. Session Initiation Protocol (SIP) is an example of a well known VoIP signaling protocol. 
     SIP provides advanced signaling and control to VoIP networks for initiating, managing, and terminating VoIP network sessions, or calls. A typical SIP enabled VoIP network includes user agents, proxy servers, and media gateways. User agents are the end users of a SIP network. User agents can be the origin or destination for a call over a VoIP network. Media gateways interwork communications for calls between VoIP networks and for calls that either originate or terminate outside of a VoIP network. Proxy servers provide registration, redirect, and location services implemented by registrar, redirect, and location server applications running on the proxy servers. In particular, registrar servers manage user agents assigned to their network domains. Redirect servers redirect SIP messages to their appropriate destinations and return location information in response to queries. Location servers share responsibility for knowing the location and status of each gateway. 
     Telephony Routing over Internet Protocol (TRIP) is a well known protocol established to effectuate messaging between location servers and gateways to keep track of the location and status of the gateways. TRIP does not run directly over IP—it must ride over a telephony protocol like SIP or H.323 because IP does not provide the infrastructure (e.g. SIP proxy server and media gateway) nor the packet structure to provide what TRIP needs to do its very specific job (dynamic building of proxy server routing tables). In a SIP only network, location servers are not utilized; rather, the proxy server uses standard Domain Name Service (DNS) methods to determine where to forward call requests. In a TRIP enabled SIP network, the location server builds a dynamic routing table based on TRIP update messages transmitted from various media gateways and location servers. The location server then accesses the resulting TRIP routing table to determine where to forward and redirect call requests. 
     TRIP enabled location servers are often referred to as TRIP speakers. A scaled down version of TRIP called TRIP-lite can be implemented on gateways. TRIP-lite transmits messaging from a gateway to at least one location server advertising the available routes and prefixes accessible through that gateway. For example, a first TRIP-lite enabled gateway might advertise to a location server that it services the 913 area code of the public switched telephone network (PSTN), while a second TRIP-lite enabled gateway advertises to the location server that it services the 816 area code of the PSTN. Thus, when a call request indicating a PSTN area code of 913 arrives into the location server, the location server knows to route that call to the first TRIP-lite enabled gateway. Other attributes advertised by TRIP-lite enabled gateways include destination prefixes, capacity to each prefix destination, and utilization levels of each trunk group terminating at the gateway. TRIP-lite allows location servers to have real-time knowledge of available gateway resources. 
     One problem with current VoIP network configurations is the inability of the networks to deliver consistently high levels of quality of service (QoS) on a per user basis. For example, when a SIP enabled location server receives multiple update messages from several TRIP-lite enabled gateways, the volume of messages could push the location server into a period of congestion. Currently, the location server has no way to prioritize the messages to ensure a basic QoS level across the network. Additionally, the location server has no way by which to ensure a QoS level for specific VoIP users of the network. Thus, the location server treats each update message as if each update message is as important as any other. However, the content of some of the update messages are typically more important than the content of others. Furthermore, some users accessing the network may be more important than other users accessing the network. Therefore, it would be useful and desirable to provide varying levels of QoS for various users when processing update messages to build network routing tables. 
     SUMMARY OF THE INVENTION 
     An embodiment of the invention solves the above problems and other problems by providing systems, methods, and software that prioritize update messages from gateways based on users associated with the gateways. A communication system in an embodiment of the invention includes a call control system, a plurality of network nodes, and a gateway coupled to the call control system and coupled to the plurality of network nodes. The gateway is configured to interwork communications between the plurality of network nodes and, responsive to a first status change associated with a first network node of the plurality of network nodes, transfers a first update message to the call control system wherein the first update message indicates the gateway, the first status change, and the first network node. The call control system, responsive to receiving the first update message, processes the first update message to determine a first user associated with the first network node and to determine a first priority for the first update message based on the first user associated with the first network node. 
     In another embodiment of the invention, the gateway, responsive to a second status change associated with a second network node of the plurality of network nodes, transfers a second update message to the call control system wherein the second update message indicates the gateway, the second status change, and the second network node, and the call control system, responsive to receiving the second update message, processes the second update message to determine a second user associated with the second network node and determine a second priority for the second update message based on the second user associated with the second network node. 
     In another embodiment of the invention, the call control system processes the first update message to determine a first quality of service level for the first user and determines the first priority for the first update message based on the first quality of service level for the first user. 
     In another embodiment of the invention, the call control system processes the second update message to determine a second quality of service level for the second user and determine the second priority for the second update message based on the second quality of service level for the second user. 
     In another embodiment of the invention, the call control system, in response to entering a period of congestion, drops either the first update message or the second update message in an order according to the first and second priorities determined for the first and second update messages. 
     In another embodiment of the invention, the call control system processes the first and second update messages to update a routing table in an order according to the first and second priorities determined for the first and second update messages. 
     In some embodiments of the invention, the routing table comprises a telephony routing over internet protocol (TRIP) routing table. 
     In some embodiments of the invention, the first network node comprises a wireless base station. 
     In some embodiments of the invention, the gateway comprises a telephony routing over internet protocol-lite (TRIP-lite) enabled gateway. 
     In some embodiments of the invention, the call control system comprises a telephony routing over internet protocol (TRIP) enabled location server. 
     Advantageously, an embodiment of the invention determines the priority of update messages based on the various users associated with various gateways. Such a method provides an efficient mechanism for clearing periods of congestion. Additionally, determining a priority based on a user results in a system by which important network customers receive service commensurate with their importance. For example, an enterprise such as a large corporation may negotiate with the service provider of a VoIP network for a certain level of service for certain users. Rather than provide the same high level of service to all employees of the corporation, the service provider can provide a high level of service to some employees, and a lower level of service to other employees. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a communication system in an embodiment of the invention. 
         FIG. 2  illustrates the operation of a communication system in an embodiment of the invention. 
         FIG. 3  illustrates the operation of a communication system in an embodiment of the invention. 
         FIG. 4  illustrates a communication system in an embodiment of the invention. 
         FIG. 5  illustrates a computer system in an embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       FIGS. 1-5  and the following description depict specific embodiments of the invention to teach those skilled in the art how to make and use the best mode of the invention. For the purpose of teaching inventive principles, some conventional aspects have been simplified or omitted. Those skilled in the art will appreciate variations from these embodiments that fall within the scope of the invention. Those skilled in the art will appreciate that the features described below can be combined in various ways to form multiple embodiments of the invention. As a result, the invention is not limited to the specific embodiments described below, but only by the claims and their equivalents. 
     First Embodiment Configuration and Operation 
     FIGS.  1 - 3   
       FIG. 1  illustrates communication system  100  in an embodiment of the invention. Communication system  100  includes call control system  130 , gateway  120 , and network nodes  105 ,  106 . Gateway  120  is coupled to call control system  110  and network nodes  105 ,  106 . 
     Gateway  120  is any gateway capable of interworking communications between network nodes  105 ,  106 . Gateway  120  is also any gateway, responsive to status changes of network nodes  105 ,  106  capable of transferring update messages to call control system  130 . Each update message could indicate the gateway, a network node undergoing a status change, and the status change. An example of a status change includes the network node going offline, reducing capacity, increasing capacity, coming online, or other changes of status. 
     Call control system  130  is any call control system capable of receiving update messages from gateway  120 . Additionally, call control system  130  is any call control system capable of processing the update messages to determine a priority associated with each update message by determining users associated with network nodes  105 ,  106  indicated in the update messages. Call control system  130  is also any call control system capable of processing the update messages to determine quality of service (QoS) levels for the users associated with network nodes  105 ,  106  and to determine the priorities based on the QoS levels for the users. 
     Network nodes  105 ,  106  are any network nodes capable of transferring and receiving communications to and from gateway  120 . Network nodes  105 ,  106  could be, for example, sectors of the public switched telephone network (PSTN). For instance, each one of network nodes  105 ,  106  could be a particular area code of the PSTN. Each one of network nodes  105 ,  106  could also be nodes of a packet communications network. Network nodes  105 ,  106  could also be cells of a wireless network. For example, each node could represent a wireless base station that services a cell of a wireless network. A user uses a communication device, such as a wireless phone, to access communication network  100  through one of network nodes  105 ,  106 . 
       FIG. 2  illustrates the operation of communication system  100  in an embodiment of the invention. To begin, a status change occurs with respect to network node  105 . For example, gateway  120  typically interworks communications to and from network node  105 . Gateway  120  could go offline with respect to network node  105 . Alternatively, gateway  120  could come online with respect to network node  105 . In response gateway  120  transfers an update message to call control system  130  (Step  210 ). 
     Next, call control system  130  receives the update message. The update message indicates gateway  120 , network node  105 , and the status change associated with network node  105 . Call control system  130  processes the update message to determine a user associated with network node  105 . For example, call control system  130  identifies a particular user accessing communication network  100  using a cell phone in communication with network node  105 . In this example, network node  105  could be a wireless base station transceiver. Call control system then determines a priority associated with the update message based on the particular user (Step  230 ). For example, the user could have rights to a high quality of service level relative to a normal group of users. Call control system  130  should then assign a high priority to the update message. 
       FIG. 3  further illustrates the operation of communication system  100  in an embodiment of the invention. A status change could occur with respect to network node  106 . In such a case, gateway  120  transfers another update message to call control system  130 . Call control system  130  receives the update message which indicates the status change associated with network node  106  and processes the update message to determine a user associated with network node  106 . Call control system  130  then determines a priority associated with the update message based on the user associated with network node  106 . 
     Upon receiving both update messages (Step  310 ) and determining priorities for both update messages, call control system  130  determines if the priorities for each update message differ (Step  320 ). If the priorities are the same, then call control system  130  processes the update messages to update a routing table (Step  340 ) in the order that the update messages were received. The routing table holds data related to routes for routing communications. Call control system  130  updates the routing table by indicating the status change for any routes associated with gateway  120  and network nodes  105 ,  106 . 
     If the priorities assigned to the update messages differ, call control system  130  determines whether or not an update message should be dropped (Step  330 ). For example, if call control system  130  is in a period of message congestion, dropping some messages lessens the congestion. If a message should be dropped, call control system  130  drops one of the update messages based on their order of priority (Step  350 ). If messages need not be dropped, then call control system  130  processes the update messages in the order they were received to update the routing table (Step  340 ). 
     Second Embodiment Configuration and Operation 
     FIG.  4   
       FIG. 4  illustrates communication network  400  in an embodiment of the invention. Communication network  400  includes domain  410 , domain  411 , and PSTN  480 . Domain  410  is coupled to domain  411  by gateway  421  and gateway  422 . Domain  410  is coupled to PSTN  480  by gateways  423 ,  422 . Domain  411  is also coupled to PSTN  480  by gateway  422 . Domain  410  also includes call control system  430 , cell  417 , cell  472 , routing system  450 , agent  461 , and agent  462 . Domain  411  also includes call control system  431 , cell  473 , cell  474 , agent  463 , agent  464 , and routing system  451 . 
     In this embodiment, domain  410  represents any logical network such as a VoIP network, local area network (LAN), wide area network (WAN), metropolitan area network (MAN), or other similar network aggregations. Similarly, domain  411  represents any logical network such as a VoIP network, LAN, WAN, or MAN. For example, domains  410  and  411  could be enterprise networks. In another example, domains  410  and  411  could be campus networks. 
     Cells  471 ,  472  are communication cells of domain  410 . For example, cells  471 ,  472  could be wireless base stations in communication with wireless devices. Cells  471 ,  472  would then transfer communications for the wireless devices to and from routing system  450 . Routing system  450  would then route the communications to their appropriate destinations according to routing instructions for the communications. Agents  461 ,  462  could be wireless devices in communication with cells  471 ,  472 . 
     Gateway  421  is any gateway capable of interworking communications between domain  410  and domain  411 . Gateway  421  is also any gateway capable of transferring update messages to call control systems  430 ,  431 . Similarly, gateway  422  is any gateway capable of interworking communications between domain  410  and domain  411  and transferring update messages to call control systems  430 ,  431 . Gateway  423  is any gateway capable of interworking communications between domain  410  and PSTN  480 . Gateway  423  is also any gateway capable of transferring update messages to call control system  430 . Gateways  421 ,  422 ,  423  are commonly referred to in the art as a media gateways. 
     Call control system  423  is any call control system capable of receiving and processing update messages from gateways  421 ,  422 ,  423 . Call control system  423  is also any call control system capable of receiving and processing session request messages from agents  461 ,  462 . Additionally, call control system  430  is any call control system capable of determining a priority for the update messages and updating a routing table based on the update messages. Call control system  431  is any call control system capable of receiving and processing update message from gateways  421 ,  422 . Additionally, call control system  431  is any call control system capable of determining a priority for the update messages and updating a routing table based on the update messages. Call control system  431  is also any call control system capable of receiving and processing session request messages from agents  463 ,  464 . Call control systems  430 ,  431  are commonly referred to by those skilled in the art as media gateway controllers or as soft switches. 
     In this embodiment of the invention, call control systems  430 ,  431  are proxy servers each running an instance of a location server application. The location servers running on call control systems  430  and  431  are SIP and TRIP enabled. TRIP enabled location servers are commonly referred to in the art as TRIP speakers. Similarly, gateways  421 ,  422 ,  423  are TRIP-lite enabled gateways. Thus, the messaging that occurs between gateways  421 ,  422 ,  423 , and call control systems  430 ,  431  occurs in accordance with TRIP. The routing tables updated by call control systems  430 ,  431  are TRIP routing tables. 
     Agents  461 ,  462 ,  463 ,  464  are SIP enabled wireless phones and could be referred to as a SIP client, or a soft SIP client. A SIP phone is assigned an identifier (e.g. SIPuser@domain.com) and can receive incoming calls and place outgoing calls. In a basic SIP network, the proxy server can forward an incoming call request to the next proxy server along the path to the called phone. It also can provide information back to a caller to provide destination information so that the caller can reach the destination SIP phone directly. Cells  471 ,  472 ,  474 ,  474  therefore provide network nodes for agents  461 ,  462 ,  463 ,  464 . 
     Gateway  423  also serves as a signaling conversion point for signaling from PSTN  480 . Gateway  423  serves a particular node of PSTN  480 . For example, gateway  423  converts communications from a switch in PSTN  480  to a protocol for domain  410 , such as VoIP. Gateway  423  serves particular nodes or area codes of PSTN  480 . As known to those skilled in the art, PSTN  480  utilizes the SS7 signaling protocol. Gateway  423  is capable of interworking SS7 signaling to a protocol appropriate for domain  410 . Similarly, gateway  422  also serves a particular node of PSTN  480  and converts signaling and communications to and from formats compatible with domains  410 ,  411 . 
     The following describes the operation of communication network  400  in an embodiment of the invention. As discussed above, call control systems  430 ,  431  are responsible for monitoring the status of various gateways within domains  410 ,  411 . Specifically, call control system  430  keeps track of the status of gateways  421 ,  422  and  423 . Call control system  431  monitors the status of gateways  421 ,  422 , and  423 . Call control systems  430 ,  431  exchange SIP update messages to update each other on the status of other gateways to which they are not directly connected. 
     When a user desires to place a call using agent  461 , agent  461  transmits a SIP session request to call control system  430 . Call control system  430  is able to determine the best route for the call based on several factors such as available routes, distance, and cost. The SIP session request indicates the identity of the user and the domain of the user in the format of SIPuser@domain.com. Call control system  430  knows from the SIP session request whether or not the user is part of domain  410 . For example, domain  430  could be a campus of a corporate enterprise and the user could be an employee of the corporate enterprise. 
     Cells  471  and  472  are wireless base stations situated throughout the campus. Thus, when a user uses a SIP agent to initiate a SIP VoIP session, call control system  430  stores the identity of the user in association with the cell utilized by the user. Furthermore, a SIP session request typically indicates a destination for the SIP session. Call control system  430  therefore stores not only the identity of the user and the cell, but also the specific gateway utilized to connect the user with the destination. The gateway can be stored in association with the user in a modified TRIP routing table. 
     However, while callers commence SIP sessions, many other calls and operations are occurring nearly simultaneously within and across domains  410 ,  411 . The level of activity within and across domains  410 ,  411  impacts how quickly, efficiently, and accurately call control systems  430 ,  431  are able to process call requests, call forwarding requests, update messages, and all other types of messaging and activity. 
     Call control systems  430 ,  431  therefore employ SIP and TRIP for call control. For instance, call control system  430  runs an instance of a SIP and TRIP enabled location server for managing the operational aspects of gateways  421 ,  422 , and  423 . When. SIP agent  461  initiates the call to SIP agent  463 , SIP agent  461  alerts call control system  430  of the requested call by way of a SIP session request. Call control system  430  accesses a TRIP routing table to determine the appropriate outgoing gateway for the call. Upon determining that gateway  421  is the appropriate gateway for the call, call control system stores the identity of the user of agent  461  in association with gateway  421 . In this example, the user of agent  461  is a high level employee of the corporate enterprise. 
     Another user utilizing SIP agent  462  initiates a call to SIP agent  464 . A SIP session request is transmitted from agent  462  to call control system. Call control system determines that gateway  422  is the appropriate gateway for the call from agent  462  to agent  464 . In this example, the user utilizing agent  462  is a low level employee of the corporate enterprise. 
     Call control system  430  also continually receives update messages from various gateways indicating status changes of the gateways. For example, call control system  430  receives an update message from gateway  422  indicating that the switch in PSTN  480  which gateway  422  services has gone offline. Call control system  430  also receives an update message from gateway  423  indicating that a switch in PSTN  480  services by gateway  423  has come online. Call control system  430  also receives an update message from gateway  421  indicating that gateway  421  has increased bandwidth for interworking communications to domain  411 . 
     In response to receiving the update messages, call control system  430  processes the update messages to determine particular users associated with the gateways. In this example, call control system  430  determines that the user utilizing agent  461  is associated with gateway  421  and that the user utilizing agent  462  is associated with gateway  422 . Call control system  430  also determines that the user utilizing agent  461  is a high level employee of the corporate enterprise and that the user utilizing agent  462  is a low level employee of the corporate enterprise. No users are associated with gateway  423 . Based on the employment level within the corporate enterprise, call control system  430  determines that the user of agent  461  should receive a higher quality of service level than the user of agent  462 . Thus, call control system  430  assigns a high priority to the update message from gateway  421 , and a low priority to the update message from gateway  422 . 
     While  FIG. 4  illustrates call control system  430  as coupled to only three gateways, call control system  430  could be coupled to many more gateways. In such a case, the volume and frequency of update messages received by call control system  430  could reach a level as to cause congestion within call control system  430 . At such a time, call control system  430  must decide which update messages to drop and which to retain in order to clear the congestion caused by the high level of update message traffic. By prioritizing update messages based on the user associated with the gateways, call control system  430  is able to clear congestion without discarding some update messages that are more important than others. 
     A period of congestion could be caused, for example, by the situation wherein call control system  430  receives three update messages from gateways  421 ,  422 , and  423 . If call control system  430  is not in a period of congestion, the update messages are processed in the respective order they were received, and call control system  430  updates a TRIP routing table based on the content of the messages. However, if call control system  430  is in a period of congestion, some of the messages must be dropped to relieve the congestion. Call control system  430  therefore drops the update message from gateway  423 . Next, call control system  430  drops the update message from gateway  422 . Lastly, if required, call control system  430  drops the update message from gateway  421 . Update messages from gateway  421  receive a higher quality of service level than update messages from other gateways. The high level employee using agent  461  also receives a higher quality of service level than the low level employee using agent  462  because the gateway servicing the high level employee&#39;s call receives processing preference. 
     Call control system  430  determines the priority of update messages based on the various users associated with various gateways. Such a method provides an efficient mechanism for clearing periods of congestion. Additionally, determining a priority based on a user results in a system by which important network customers receive service commensurate with their importance. For example, an enterprise such as a large corporation may negotiate with the service provider of a VoIP network for a certain level of service for certain users. Rather than provide the same high level of service to all employees of the corporation, the service provider can provide a high level of service to some employees, and a lower level of service to other employees. 
     Computer System  
     FIG.  5   
       FIG. 5  illustrates computer system  500  in an embodiment of the invention. Computer system  500  includes interface  520 , processing system  530 , storage system  540 , and software  550 . Storage system  540  stores software  550 . Processing system  530  is linked to interface  520 . Computer system  500  could be comprised of a programmed general-purpose computer, although those skilled in the art will appreciate that programmable or special purpose circuitry and equipment may be used. Computer system  500  may use a client server architecture where operations are distributed among a server system and client devices that together comprise elements  520 - 550 . 
     Interface  520  could comprise a network interface card, modem, port, or some other communication device. Signaling interface  520  may be distributed among multiple communication devices. Interface  530  could comprise a computer microprocessor, logic circuit, or some other processing device. Processing system  530  may be distributed among multiple processing devices. Storage system  540  could comprise a disk, tape, integrated circuit, server, or some other memory device. Storage system  540  may be distributed among multiple memory devices. 
     Processing system  530  retrieves and executes software  550  from storage system  540 . Software  550  may comprise an operating system, utilities, drivers, networking software, and other software typically loaded onto a general-purpose computer. Software  550  could also comprise an application program, firmware, or some other form of machine-readable processing instructions. When executed by the processing system  530 , software  550  directs processing system  530  to operate as described for call control systems  130 ,  430 , and  431 .