Abstract:
Calls are routed in a hybrid telecommunications system including a switched communications network and a packet transmission network. A gateway server provides file transfer services in response to a user initiating a call. Calls and data are routed over a hybrid network including a satellite facility. The satellite facility receives data streams at a stream gateway, receives data files and stores and forwards the data files to file gateways as directed by a scheduling service according to the subscriber and the data. All data is multiplexed with authentication and session information and transmitted through orbiting satellite links or the Internet to a receiving facility. Transmission status is returned to the transmitting facility and the data is retransmitted accordingly. The receiving facility decodes the satellite transmission data and transmits the data to client device(s) as directed by a scheduling service according to the subscriber and the data.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is related to U.S. patent application Ser. No. 08/746,901, filed Nov. 18, 1996, entitled System, Method and Article of Manufacture For Selecting a Gateway of a Hybrid Communication System Architecture, to Elliot, which is incorporated by reference in its entirety. 
     This application claims the benefit of U.S. Provisional Application No. 60/071,755, filed Jan. 16, 1998. 
    
    
     COPYRIGHT NOTIFICATION 
     Portions of this patent application contain materials that are subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document, or the patent disclosure as it appears in the Patent and Trademark Office. 
     FIELD OF THE INVENTION 
     This invention generally relates to improvements in computer systems, and, more specifically, to utilizing satellite broadcast technology as a bridge between telephony operations and the Internet. 
     BACKGROUND OF THE INVENTION 
     Traditionally, data has been delivered to network-connected desktop personal computers either by broadcasting or unicasting, while the need for multicasting data has been unsatisfied. Broadcasting is a form of addressing wherein the destination address specifies all destinations; all destinations indiscriminately receive the data whether or not the data is needed by the destination computer. Where data is not needed at a particular network-connected personal computer, the transmission of the data is an inefficient use of resources. This can be particularly disabling to a network that does not have sufficient bandwidth capacity for all of the data traffic. Broadcasting is less efficient in direct relation to the proportion of users in the community of the broadcast that do not need the broadcast data. 
     In contrast, unicasting is a form of addressing where the destination address specifies a single destination. Unicasting eliminates the unnecessary transmission of data to destinations that have no need for the data, but is still inefficient because the data will be replicated on the network for each individual destination. For example, when data is transmitted to 20 personal computers connected to a server, 20 transmissions of the data will be made each with a different individual destination address. 
     Where data needs to be transmitted to a limited set of all network-connected personal computers, transmission-using broadcasting or unicasting falls short of efficient resource use. Multicasting offers more efficient resource use. Multicasting is a form of addressing wherein a source sends data to a server and the server sends one copy of the data to each of the destination computers. This form of addressing is particularly beneficial where the link between the source and the server has limited capacity or high cost because only one copy of the data that is intended for multiple recipients is transmitted to the server. Multicasting makes the most efficient use of an expensive link or a link that has insufficient capacity for transmission to multiple destinations by reducing the number of transmissions across the critical link to one, rather than requiring that multiple transmissions be made for each destination address. 
     One arena where multicasting is implemented is the Internet. Multimedia applications involve text, graphics, voice, video and hypertext operations. Multimedia applications typically require large amounts of data in comparison to traditional computer applications. The Internet has increasingly become the communication network of choice for the consumer marketplace. Multimedia applications exist on the Internet, but the throughput of the Internet limits the usefulness of multimedia applications because multimedia applications are highly interactive and require higher throughput than the Internet can provide. The limitations on bandwidth make the Internet more suitable and efficient for low bandwidth applications such as E-mail and smaller multimedia applications. 
     The Multicast backbone (MBONE) is a virtual network on top of the Internet which supports routing of Internet Protocol (IP) multicast packets, intended for multimedia transmission. MBONE enables public access to desktop video communications. However, the quality is poor, with only 3-5 frames per second instead of the 30 frames per second of commercial television. Therefore, transmission of multimedia data via the Internet is too slow, even using multicasting. 
     Two independent technologies have emerged that provide greater speed and throughput (Internet Protocol (IP) Multicast and Digital Video Broadcast) that together have the potential to provide for transmission of multimedia information over a network. IP Multicast is an important advance in IP networking that has been under development since the early 1990&#39;s but is only now receiving broad (and growing) practical industry backing through the commercial availability of network infrastructure elements. 
     An extension of standard IP, IP Multicast allows applications to send one copy of information to a group address, and have the information transmitted to each recipient of the group requiring receipt of the information. IP Multicast is more efficient than point-to-point unicast because the source need send only once, and more efficient than broadcast since only interested nodes are impacted by transmission of the information. IP Multicast thus scales well as the number of participant and collaborations expand, and it integrates well with other new IP protocols and services, such as Quality of Service requests to support real-time multimedia. 
     However, despite the advantages of IP Multicast, its terrestrial implementation may be slow because all routers between the sender and the receivers must be IP Multicast enabled. Even then, network bandwidth may be limited for some considerable time. The demand of consumers for digital satellite TV systems has driven the development of Direct Broadcast Satellite (DBS) systems that can broadcast directly to small, low cost receiver equipment. The standard likely to become dominant on a global basis is Digital Video Broadcast (DVB) which was developed by the European Broadcasting Union. 
     DVB specifies standards for the digital broadcast of video, sound and data across satellite (DVB-S), cable (DVB-C) and SMATV (DVB-CS) data link layers. DVB specifies common conformance standards at several levels including channel coding (Reed-Soloman forward error correction), transport layer (MPEG-2 Systems Transport bitstream) and elementary stream layers (MPEG-2 for video encoding and MPEG-1 for audio encoding). An elemental stream is a single, digitally coded component of a multimedia channel (e.g. a single coded video or audio stream). MPEG-2 elemental stream encoding thus provides good VHS quality video at 1.5-2 Megabits and studio production quality video at approximately 6-8 Megabits. 
     MPEG-2 transport enables video, audio and data to be multiplexed onto the physical channel of choice, with DVB specifying the remaining system elements for each transport media being used. For example, with satellite communications, DVB specifies the physical channel (single 38 Megabits satellite transponder), signal/noise ratio and channel coding (e.g. 2 bit/symbol QPSK modulation). 
     Satellite communications offer sufficient bandwidth for remote multimedia applications. However, satellite connections for the typical computer user are practically non-existent and expensive and do not allow for use of economical open client/server technologies. A client/server architecture is an economical, proven and common form of distributed system wherein software is split between server tasks and client tasks. A client sends requests to a server, according to some protocol, asking for information or action, and the server responds. There may be either one centralized server or several distributed ones. This model allows clients and servers to be placed independently on nodes in a network, possibly on different hardware and operating systems appropriate to their function, e.g. fast server with an inexpensive client. 
     There is a rapidly increasing market demand for network based application services that enable the efficient operation of computer applications which are one-to-many in their information flow and which require high network bandwidth. Major advances in digital transmission, encoding and internetworking technology and the advent of direct broadcast satellite have matched this. This market need, combined with the emerging technological capability, has prompted development in accordance with a preferred embodiment. The engineering challenge was to develop a system solution that makes optimum use of emerging digital broadcast technology such as DVB/MPEG while seamlessly integrating into an emerging IP Multicast standard for data technology. With such an emergent service, the architecture of any solution must also be scaleable from an early system for deployment as part of an individual customer solution, through to a multi-customer service platform capable of simultaneously supporting multiple large business customers. 
     There are two basic models for delivery of information to end users: (a) information can be requested by the end user of a central source (pull model), or (b) information can be sent from the central source to the end user (push model). Established LAN and WAN technologies, applications and services are very efficient at supporting the pull model of information flow. However, as advanced information technology becomes critical to organizations, there is a rapidly increasing market demand for information technology and network services that efficiently enable push oriented, one-to-many information flow. 
     In addition, even when data compression is used, the increasingly multimedia nature of applications requires high bandwidth support of a one-to-many information flow. And even many non-multimedia applications require high bandwidth for the timely transfer of large files of information. The concept of multicasting was originally developed to provide application and inter-network services in response to a demand for high bandwidth one-to-many services. Multicasting utilizes the natural broadcast capabilities of a satellite infrastructure, while smoothly integrating with existing and emerging terrestrial data network services and pull oriented application services. 
     A solution to the problems of transmitting multimedia and supporting call processing across the economical Internet while utilizing the high throughput of orbital satellites would integrate the Internet and satellites into a hybrid telecommunications system using client/server technologies. 
     The present invention relates to the integration of satellite transmission facilities with the Internet and telephony systems, and more specifically, to a system, method and article of manufacture for using the Internet and satellite transmissions as the communication backbone of a distributed client/server communication system architecture while maintaining a rich array of call processing features. 
     SUMMARY 
     According to a broad aspect of a preferred embodiment of the invention, telephone calls, data and other multimedia information are routed through a switched network which includes transfer of information across the Internet and a satellite broadcast facility. A hybrid telecommunications system includes a switched communication network. A packet transmission network is coupled to the switched communications network. A call router is coupled to the switched communications network and the packet transmission network. A gateway server in communication with the call router provides file transfer services to a user connected to the switched communications network including routing over the Internet and satellite broadcasting facilities. The identity of the user is optionally authenticated by an authentication server. 
     In a further aspect of a preferred embodiment of the invention, an exterior packet filter is coupled to the call router and the gateway server. The exterior packet filter is configured to accept communications originating from a predetermined set of addresses. 
     In still another aspect of the invention, the gateway server is configured to route any messages larger than a certain size to a satellite broadcast facility if the messages are traveling more than 1000 miles. 
     In yet another aspect of the invention, a production token ring network is in communication with the gateway server. The production token ring network is optionally coupled to an interior packet filter configured to accept only communications originating from a predetermined set of addresses. 
    
    
     DESCRIPTION OF THE DRAWINGS 
     FIG. 1 illustrates the general topology of a Transmitting Facility and a Receiving Facility communicating via a network in accordance with a preferred embodiment; 
     FIG. 2A illustrates the general topology of a Transmitting Facility; 
     FIG. 2B illustrates the general topology of a Broadcast Operation Center; 
     FIG. 3 illustrates the topology of a Content Provider Facility and a Broadcasting Operation Center including an Input Gateway, an Information Store and Output Gateways; 
     FIG. 4 illustrates Output Gateways communicating with an uplink Facility of the Transmitting Facility; 
     FIG. 5 illustrates an uplink technical core; 
     FIG. 6 illustrates a Receiving Facility; 
     FIG. 7 illustrates a layered system architecture; 
     FIG. 8 illustrates an application services layer; and 
     FIG. 9 illustrates a functional decomposition of architectural layers. 
    
    
     DETAILED DESCRIPTION 
     To assist in clarifying the technical subject matter of this application, a few terms are defined at the outset. 
     
       
         
               
             
               
               
             
               
               
               
             
               
               
               
               
             
               
               
               
             
           
               
                 TABLE 1 
               
             
             
               
                   
               
               
                 Universal Terms 
               
             
          
           
               
                   
                 Definition of 
               
               
                   
                 terms 
               
               
                   
                   
               
             
          
           
               
                   
                 Bandwidth 
                 Measure of the amount of data passing 
               
               
                   
                   
                 through a network at a given time. 
               
               
                   
                 Bridge 
                 A network bridge works on layer 2 
               
               
                   
                   
                 of the OSI model. Thus, bridges 
               
               
                   
                   
                 are protocol independent. Network 
               
               
                   
                   
                 traffic is typically forwarded to 
               
               
                   
                   
                 correct bridge interfaces based on 
               
               
                   
                   
                 MAC address. 
               
               
                   
                 Distance Vector 
                 DVMRP is the original IP Multicast 
               
               
                   
                 Multicast 
                 routing protocol. It was designed to 
               
               
                   
                 Routing Protocol 
                 run over both multicast capable LANs 
               
               
                   
                 (DVMRP) 
                 (like Ethernet) as well as through 
               
               
                   
                   
                 non-multicast capable routers. In this 
               
               
                   
                   
                 case, the IP Multicast packets are 
               
               
                   
                   
                 “tunneled” through the routers as 
               
               
                   
                   
                 unicast packets. This replicates the 
               
               
                   
                   
                 packets and has an effect on 
               
               
                   
                   
                 performance but has provided an 
               
               
                   
                   
                 intermediate solution for IP Multicast 
               
               
                   
                   
                 routing on the Internet while router 
               
               
                   
                   
                 vendors decide to support native IP 
               
               
                   
                   
                 Multicast routing. 
               
               
                   
                 Duplex 
                 Two-way point to point 
               
               
                   
                 Communications 
                 communications. 
               
               
                   
                 Internet 
                 A group of networks that are 
               
               
                   
                   
                 interconnected so that they appear to 
               
               
                   
                   
                 be one continuous network, and can be 
               
               
                   
                   
                 addressed seamlessly at the Network 
               
               
                   
                   
                 Layer Three of the OSI model. Also, 
               
               
                   
                   
                 the “Internet” (capital I) is the name 
               
               
                   
                   
                 given to the global network also 
               
               
                   
                   
                 known as the “World Wide Web”. 
               
               
                   
                 Internet Group 
                 IGMP was primarily designed for 
               
               
                   
                 Management 
                 hosts on multi-access networks to 
               
               
                   
                 Protocol 
                 inform locally attached routers of their 
               
               
                   
                 (IGMP) 
                 group membership information. This 
               
               
                   
                   
                 is performed by hosts multicasting 
               
               
                   
                   
                 IGMP Host Membership Reports. 
               
               
                   
                   
                 Multicast routers listen for these 
               
               
                   
                   
                 messages and then can exchange 
               
               
                   
                   
                 group membership information with 
               
               
                   
                   
                 other multicast routers. This allows 
               
               
                   
                   
                 distribution trees to be formed to 
               
               
                   
                   
                 deliver multicast datagrams. The 
               
               
                   
                   
                 original version of IGMP was defined 
               
               
                   
                   
                 in RFC 1112. 
               
               
                   
                 Internet 
                 An unreliable, connectionless 
               
               
                   
                 Protocols (IP) 
                 datagram delivery service that allows 
               
               
                   
                   
                 networks to interact in a coherent 
               
               
                   
                   
                 manner and to pass data across 
               
               
                   
                   
                 multiple networks. The TCP/IP 
               
               
                   
                   
                 standard protocol defines the IP 
               
               
                   
                   
                 datagram as the unit of information 
               
               
                   
                   
                 passed across an Internet and provides 
               
               
                   
                   
                 the basis for connectionless packet 
               
               
                   
                   
                 delivery service. IP includes the 
               
               
                   
                   
                 ICMP control and error message 
               
               
                   
                   
                 protocol as an integral part. It 
               
               
                   
                   
                 provides the functional equivalent of 
               
               
                   
                   
                 ISO OSI Network Services. 
               
               
                   
                 Intranet 
                 A subset of a larger network. An 
               
               
                   
                   
                 interconnected set of networks within 
               
               
                   
                   
                 a particular domain, such as a 
               
               
                   
                   
                 corporation, using IP or proprietary 
               
               
                   
                   
                 protocols to communicate between 
               
               
                   
                   
                 networks. 
               
               
                   
                 IP Address 
                 The 32-bit address assigned to hosts 
               
               
                   
                   
                 that want to participate in a TCP/IP 
               
               
                   
                   
                 Internet. 
               
               
                   
                 IP datagram 
                 The basic unit of information passed 
               
               
                   
                   
                 across a TCP/IP Internet. 
               
               
                   
                 Local Area 
                 A network physically confined to a 
               
               
                   
                 Network (LAN) 
                 small region of space, typically within 
               
               
                   
                   
                 a single building; contrasting with a 
               
               
                   
                   
                 Wide Area Network (WAN), which 
               
               
                   
                   
                 may be countrywide or even 
               
               
                   
                   
                 worldwide. 
               
               
                   
                 Multicast 
                 IP-Multicast is the class-D addressing 
               
               
                   
                   
                 scheme in IP developed by Steve 
               
               
                   
                   
                 Deering at Xerox PARC. A set of 
               
               
                   
                   
                 Internet Protocols designed to allow 
               
               
                   
                   
                 point to multipoint distribution of 
               
               
                   
                   
                 data. 
               
               
                   
                 Multicast 
                 An address, within a range of IP 
               
               
                   
                 Address 
                 addresses, that identified the data as a 
               
               
                   
                   
                 multicast session. 
               
               
                   
                 Multimedia 
                 Digital information intended to 
               
               
                   
                   
                 interface with the human senses. 
               
               
                   
                 Protocol 
                 PIM was designed to take advantage 
               
               
                   
                 Independent 
                 of two existing multicast routing 
               
               
                   
                 Multicast 
                 protocols, DVMRP and CBT. It 
               
               
                   
                 (PIM) 
                 exhibits the behavior of a protocol in a 
               
               
                   
                   
                 region of dense group membership 
               
               
                   
                   
                 flooding multicast packets using 
               
               
                   
                   
                 Reverse Path Multicasting, while also 
               
               
                   
                   
                 taking advantage of the work done for 
               
               
                   
                   
                 sparse group membership in Core 
               
               
                   
                   
                 Based Trees. Hence, the protocol has 
               
               
                   
                   
                 two modes, dense and sparse. 
               
               
                   
                 Protocol 
                 The Protocol Independent Multicast - 
               
               
                   
                 Independent 
                 Sparse Mode (PIM-SM) architecture: 
               
             
          
           
               
                   
                 Multicast - 
                 • 
                 maintains the traditional IP 
               
               
                   
                 Sparse Mode 
                   
                 multicast service model of 
               
               
                   
                 (PIM-SM) 
                   
                 receiver-initiated membership; 
               
               
                   
                   
                 • 
                 uses explicit joins that propagate 
               
               
                   
                   
                   
                 hop-by-hop from members&#39; 
               
               
                   
                   
                   
                 directly connected routers toward 
               
               
                   
                   
                   
                 the distribution tree. 
               
               
                   
                   
                 • 
                 builds a shared multicast 
               
               
                   
                   
                   
                 distribution tree centered at a 
               
               
                   
                   
                   
                 Rendezvous Point, and then builds 
               
               
                   
                   
                   
                 source-specific trees for those 
               
               
                   
                   
                   
                 sources whose data traffic 
               
               
                   
                   
                   
                 warrants it. 
               
               
                   
                   
                 • 
                 is not dependent on a specific 
               
               
                   
                   
                   
                 unicast routing protocol; 
               
               
                   
                   
                 • 
                 uses soft-state mechanisms to 
               
               
                   
                   
                   
                 adapt to underlying network 
               
               
                   
                   
                   
                 conditions and group dynamics. 
               
             
          
           
               
                   
                   
                 The robustness, flexibility, and scaling 
               
               
                   
                   
                 properties of this architecture make it 
               
               
                   
                   
                 well suited to large heterogeneous 
               
               
                   
                   
                 internetworks. 
               
               
                   
                 Routers 
                 An OSI network layer (Layer 3) 
               
               
                   
                   
                 device that can decide which of 
               
               
                   
                   
                 several paths network traffic will 
               
               
                   
                   
                 follow based on some optimality 
               
               
                   
                   
                 metric. Routers forward packets from 
               
               
                   
                   
                 one network to another, based on 
               
               
                   
                   
                 network layer information. 
               
               
                   
                 Simplex 
                 One-way communications. In a 
               
               
                   
                 Communications 
                 simplex environment, there is only a 
               
               
                   
                   
                 transmit or receive path available 
               
               
                   
                   
                 between two network components. 
               
               
                   
                 The OSI Model 
                 The ISO seven-layer model attempts 
               
               
                   
                   
                 to provide a way of partitioning any 
               
               
                   
                   
                 computer network into independent 
               
               
                   
                   
                 modules from the lowest (physical) 
               
               
                   
                   
                 layer to the highest (application) layer. 
               
               
                   
                   
                 Many different specifications exist at 
               
               
                   
                   
                 each of these layers. 
               
               
                   
                 Tunneling 
                 Encapsulation of network traffic at 
               
               
                   
                   
                 one interface for decapsulation by a 
               
               
                   
                   
                 peer interface. Also used to establish 
               
               
                   
                   
                 virtual connecting interfaces between 
               
               
                   
                   
                 subnets. 
               
               
                   
                 Unicast 
                 Single destination addressing. 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
             
           
               
                 TABLE 2 
               
             
             
               
                   
               
               
                 Multicast Network Terms 
               
             
          
           
               
                   
                 Definition of 
               
               
                   
                 Terms 
               
               
                   
                   
               
             
          
           
               
                   
                 Administratively 
                 A range of Multicast addresses which 
               
               
                   
                 Scoped addresses 
                 are limited to intranet or other defined 
               
               
                   
                   
                 domains and which are not distributed 
               
               
                   
                   
                 to the general internet. 
               
               
                   
                 Application 
                 Network devices that request and 
               
               
                   
                 Clients 
                 receive multicast data from 
               
               
                   
                   
                 application servers. 
               
               
                   
                 Application 
                 The server which originates the 
               
               
                   
                 Server 
                 multicast distribution of a multicast 
               
               
                   
                   
                 application. 
               
               
                   
                 Boundary 
                 Routers which interface between the 
               
               
                   
                 Routers 
                 satellite insertion point and 
               
               
                   
                   
                 downstream clients. This is the first 
               
               
                   
                   
                 router the received multicast signal is 
               
               
                   
                   
                 distributed to. 
               
               
                   
                 Downstream 
                 Application Clients with a boundary 
               
               
                   
                 Clients 
                 router and possibly other routers, 
               
               
                   
                   
                 between them and the insertion point. 
               
               
                   
                 Downstream 
                 Routers located downstream of the 
               
               
                   
                 Routers 
                 boundary router. 
               
               
                   
                 GRE Tunneling 
                 Generic Routing Encapsulation 
               
               
                   
                   
                 Tunneling protocol developed by 
               
               
                   
                   
                 Cisco that can encapsulate a wide 
               
               
                   
                   
                 variety of protocol packet types inside 
               
               
                   
                   
                 IP tunnels, creating a virtual point-to- 
               
               
                   
                   
                 point link to Cisco routers at remote 
               
               
                   
                   
                 points over an IP internet. By 
               
               
                   
                   
                 connecting multiprotocol subnetworks 
               
               
                   
                   
                 in a single-protocol backbone 
               
               
                   
                   
                 environment, IP tunneling using GRE 
               
               
                   
                   
                 allows network expansion across a 
               
               
                   
                   
                 single-protocol backbone 
               
               
                   
                   
                 environment. 
               
               
                   
                 Infolink 
                 MCI&#39;s Intranet, based on IP. 
               
               
                   
                 Insertion Point 
                 The point where a satellite receiver is 
               
               
                   
                   
                 attached to a LAN or other network 
               
               
                   
                   
                 component. 
               
               
                   
                 Insertion Point 
                 Application Clients that are directly 
               
               
                   
                 Clients 
                 connected to the insertion point LAN. 
               
               
                   
                 IPTV 
                 A multicast application from Precept. 
               
               
                   
                 MMSE 
                 MultiMedia Services Engineering 
               
               
                   
                 Operations LAN 
                 A LAN Segment which interfaces 
               
               
                   
                 Segment 
                 between the application server, the 
               
               
                   
                   
                 downstream clients and the Operations 
               
               
                   
                   
                 Router. 
               
               
                   
                 Operations 
                 Interface router between Operations 
               
               
                   
                 Router 
                 LAN Segment, Uplink LAN Segment 
               
               
                   
                   
                 and terrestrial network. 
               
               
                   
                 Satellite 
                 The combined terrestrial and space 
               
               
                   
                 Transmission 
                 segment path from the Uplink LAN to 
               
               
                   
                 Path 
                 the receiving antenna. This path uses 
               
               
                   
                   
                 the dedicated telephony network route 
               
               
                   
                   
                 to the satellite uplink site, where the 
               
               
                   
                   
                 signal is inserted into the uplink signal 
               
               
                   
                   
                 for the appropriate satellite. The 
               
               
                   
                   
                 satellite broadcasts the signal to a 
               
               
                   
                   
                 ‘footprint’ that covers the Continental 
               
               
                   
                   
                 US with ‘spot beams’ aimed at Hawaii 
               
               
                   
                   
                 and Alaska. (spot beams optional) 
               
               
                   
                 Simplex Satellite 
                 One-way communication over a 
               
               
                   
                 Multicast 
                 satellite of a multicast datastream. 
               
               
                   
                 Uplink LAN 
                 LAN connected to the Operations 
               
               
                   
                   
                 router. This LAN distributes multicast 
               
               
                   
                   
                 traffic to the satellite. 
               
               
                   
                   
               
             
          
         
       
     
     
       
         
               
             
               
               
             
               
               
               
             
           
               
                 TABLE 3 
               
             
             
               
                   
               
               
                 Multicast Applications Terms 
               
             
          
           
               
                   
                 Definition of 
               
               
                   
                 Terms 
               
               
                   
                   
               
             
          
           
               
                   
                 CPU 
                 The Processor or chip in a computer 
               
               
                   
                   
                 that carries out all the instructions of a 
               
               
                   
                   
                 program and controls all the other 
               
               
                   
                   
                 parts of a computer. 
               
               
                   
                 Decoder 
                 A device for decompressing a 
               
               
                   
                   
                 compressed incoming bitstream, then 
               
               
                   
                   
                 splitting it into its audio and video 
               
               
                   
                   
                 components, and converting the data 
               
               
                   
                   
                 into analog signals for playback. 
               
               
                   
                 Encoder 
                 A device that records, digitizes, and 
               
               
                   
                   
                 compresses analog audio and video 
               
               
                   
                   
                 content. 
               
               
                   
                 Frame Rate 
                 The number of complete single video 
               
               
                   
                   
                 pictures that are streamed and 
               
               
                   
                   
                 measured on a per second basis. The 
               
               
                   
                   
                 acronym usually used is displayed as 
               
               
                   
                   
                 (fps). 
               
               
                   
                 Functional 
                 In System Testing, testing which 
               
               
                   
                 Testing 
                 attempts to find a discrepancy between 
               
               
                   
                   
                 a program and its specification. 
               
               
                   
                 Graphical 
                 Graphical User Interface; an 
               
               
                   
                 User Interface 
                 Interactive screen display where the 
               
               
                   
                   
                 user can move a Mouse to point the 
               
               
                   
                   
                 ‘arrow’ cursor at symbols (icons or 
               
               
                   
                   
                 buttons) that represent data or 
               
               
                   
                   
                 instructions to the machine, reducing 
               
               
                   
                   
                 the need for keyboard typing 
               
               
                   
                 I/O Operation 
                 A task on a computer that reads and/or 
               
               
                   
                   
                 writes data to an external hardware 
               
               
                   
                   
                 device such as a CD-ROM, floppy 
               
               
                   
                   
                 disk, hard drive. 
               
               
                   
                 MPEG1 
                 An International Standards 
               
               
                   
                   
                 Organization (ISO) standards that 
               
               
                   
                   
                 addresses the methods for encoding 
               
               
                   
                   
                 video and audio at bandwidth rates of 
               
               
                   
                   
                 approximately 1.5 Mbps (suitable for 
               
               
                   
                   
                 CD-ROM). 
               
               
                   
                 Parallel 
                 The ability to achieve multiple tasks 
               
               
                   
                 Processing 
                 under a single PC configured with a 
               
               
                   
                   
                 single operating system 
               
               
                   
                   
                 simultaneously. 
               
               
                   
                 RAM 
                 Random Access Memory. A device, 
               
               
                   
                   
                 often in the form of a chip (or set of 
               
               
                   
                   
                 chips) that stores Data and programs 
               
               
                   
                   
                 for immediate use by a CPU. The 
               
               
                   
                   
                 contents of RAM memory are 
               
               
                   
                   
                 normally lost when the machine is 
               
               
                   
                   
                 switched off. 
               
               
                   
                 Regression 
                 In System Testing, tests used to verify 
               
               
                   
                 Testing 
                 each new version of the system 
               
               
                   
                   
                 whenever that system is modified. It 
               
               
                   
                   
                 verifies the modification and 
               
               
                   
                   
                 investigates the impact of changes on 
               
               
                   
                   
                 the existing functions. 
               
               
                   
                 Streaming 
                 A bit sequence of compressed digital 
               
               
                   
                   
                 video. 
               
               
                   
                 Video 
                 The number of pixels per unit area 
               
               
                   
                 Resolution 
                 with the greater the number of pixels 
               
               
                   
                   
                 represent the higher the resolution. 
               
               
                   
                   
               
             
          
         
       
     
     FIG. 1 illustrates the general topology of a Transmitting Facility and a Receiving Facility communicating via a network in accordance with a preferred embodiment. The flow of data starts at a Content Source  100 . The content may be in any one of a number of digital forms, including data files and real-time data streams. Data in every form and format is enabling. The data streams may be audio or video originating from local sources or international sources. The content is transmitted to a Transmitting Facility  110  via any one of a number of methods, including network, Internet, Intranet, or radio broadcast. The data is forwarded to a satellite transmitter  120 , received and forwarded to an orbiting satellite  130 , received by a satellite receiver  140  and forwarded to a Receiving Facility  150  and transmitted to one or a plurality of destinations  160 . In the alternative, the path of transmission between the Transmitting Facility  110  and the Receiving Facility  150  may be via the Internet  170 . 
     The Transmitting Facility  110  includes a Content Provider Facility and a Broadcast Operation Center. The Receiving Facility  150  includes a Downlink Gateway, Local Program Menu Database and Application Services Facility. The flow of data via the satellite links  120 ,  130 ,  140  is unidirectional, from the Transmitting Facility  110  to the Receiving Facility  150 . The flow of data via the Internet  170  is unidirectional from the Transmitting Facility  110  to the Receiving Facility  150 , however, data indicating the success or lack of success of all content transmissions is forwarded to the Transmitting Facility  110  via the Internet or Public Switched Telephone Network or ISDN at data transmission speeds ranging from 28.8 kilobytes per second to 1.5 megabytes per second. 
     FIG. 2A illustrates the general topology of a Transmitting Facility in accordance with a preferred embodiment. A Transmitting Facility includes three major functions. The Content Provider Facility  200 , the Broadcast Operation Center  210 , and the Uplink Facilities  220 . Data is generated at the Content Provider Facility  200 , is transmitted to the Broadcast Operation Center  210 , and is transmitted to the Uplink Facility  220 . 
     FIG. 2B illustrates the general topology of a Broadcast Operation Center in accordance with a preferred embodiment. Data enters the Broadcast Operation Center through the Input Gateways  230 , which includes a File Gateway, a Schedule Gateway and a Stream Gateway. Data Streams are forwarded to Output Gateways  250 , which includes a Repair Server, a Playout Server, and shares the Stream Gateway with the Input Gateway  230 . The Stream Gateway is shared by the Input Gateways  230  and the Output Gateways  250  to accommodate the urgent transmission requirements of stream data. Data Files are transmitted to an Information Store  240  and forwarded to the Output Gateways  250 . 
     FIG. 3 illustrates the topology of a Content Provider Facility and a Broadcasting Operation Center including an Input Gateway, an Information Store and Output Gateways in accordance with a preferred embodiment. Data Streams  300  and Data Files  305  are received from external sources by a Content Provider Gateway  310 . Data Streams  300  are assumed to be RTP/UDP unicast or multicast. Authentication and protection mechanisms, such as IPSEC, may be used. Data Files  305  are transmitted via a store-and-forward manner and using conventional file transfer and may be secured through use of IPSEC, SSL, or S-HTTP. The Content Provider Gateway  310  packages the data in packets for transmission to the Broadcast Operation Center. The Content Provider Facility will encrypt all data at the application level. 
     Data Streams  300  have a high priority as a function of the urgent or real-time nature of the data, and are transmitted to an Output Gateway  330  in the Broadcast Operation Center to speed passage of the data. Data Files  305  have lower priority than Data Streams  300  and are managed by the Broadcast Operation Center on a scheduled basis. The Content Provider Gateway  310  communicates to the Broadcast Operation Center via a network using TCP/IP protocol. The communication link between the Content Provider Gateway  310  in the Content Provider Facility and a Schedule Gateway  315  in the Broadcast Operation Center is a secure SSL or S-HTTP protocol. 
     The Content Provider Gateway  310  and the Schedule Gateway  315  exchange information on the scheduling of transmission of Data Files  305 . More specifically, transmission of Data Files  305  is scheduled, revised and queried by the Schedule Gateway  315 . The Content Provider Gateway  310  transmits scheduled Data Files  305  to the Schedule Gateway  315  via a network connection using Unicast, and either File Transfer Protocol (FTP) or IPSEC. A File Gateway  320  writes the Data Files  305  to a File Store  325 , which is a data storage medium, and forwards the Data Files  305  to the Output Gateways  330  at the direction of a Subscription Manager  335 . The Subscription Manager  335  transmits scheduling information to the Output Gateways  330 . 
     FIG. 4 illustrates the Output Gateways communicating with the Uplink Facility of the Transmitting Facility in accordance with a preferred embodiment. A Content Provider Gateway  400  transmits data streams to a Stream Gateway  410 , circumventing the store-and-forward function that data files are subject to. 
     The Stream Gateway  410  functions as an FTP Proxy Gateway, which is an IP circuit gateway. A Subscription Manager  420  will transmit to the Stream Gateway  410 , a Playout Gateway  430 , and a Repair Gateway  440 , information that uniquely identifies data that passes through each of the respective gateways, which enables the respective gateways to multiplex authentication and session information such as a unique identifier, the destination uplink, timing, multicast address, checksum, and format information into the data stream. Simultaneous delivery of data streams and data files at the destination can be coordinated by multiplexing authentication and session information in the data streams and data files accordingly. 
     The Stream Gateway  410  and the Playout Gateway  430  monitor the timeliness of data to the Uplink Gateways. The Playout Gateway  430  and the Repair Gateway  440  will retrieve data files from a File Store  450  as indicated by the Subscription Manager  420 . 
     The Output Gateways will transmit data to the Uplink Gateway that is appropriate as indicated by the multiplexed session information, which is either an Internet Multicast Gateway  460 , a Fixed Service Satellite (FSS) Uplink Gateway  470 , or a Digital Broadcast Satellite (DBS) Uplink Gateway  480 . Examples of DBS services are Direct TV and ASkyB. The Uplink Gateways will convert protocols and generate frames as appropriately indicated by the session information and the needs of the respective uplink facilities. Data is transmitted by the Stream Gateway  410  to the Uplink Gateways via RTP. 
     FIG. 5 illustrates the uplink technical core in accordance with a preferred embodiment. Data Files are transmitted by the Output Gateways of the Broadcast Operation Center of the Transmitting Facility via a Digital Network Interface  500 , Data streams are transmitted via an Analog Network Interface  505 , analog data is transmitted via video tape recorder  510 , or Data is transmitted via a local content feed  515  into a 270 megabit per second network backbone  520 . A record of each transmission is made to a video tape recorder server  525 . The data is encoded to MPEG standards using an MPEG encoder  530  and encrypted using an encryptor  535 . 
     The data is encrypted according to Conditional Access (CA) protocol at CA gate  540  and multiplexed by multiplexer  545  with authentication and session information, such as a unique identifier, the destination uplink, timing, multicast address, checksum, and format information, into the data stream. The multiplexed data is mixed with 4-6 television content  550 , audio  555 , and data  560 . Forward Error Correction (FEC) is added to the data  565 . The data  565  is transmitted and modulated according to Quadrature Phase Shift Keying (QPSK) specifications  570 , a radio frequency (RF) exciter  575  intervenes in the data transmission, and a RF power amplifier  580  amplifies the data signal. 
     FIG. 6 illustrates the Receiving Facility in accordance with a preferred embodiment. The Receiving Facility includes four primary components: a Local Program Menu Database  605 , Application Services  610  one or more client computers  615 , and a Downlink Gateway  620 . Data that is received by the satellite receiver  140 , FIG. 1, is transmitted to a Satellite Downlink Gateway  600 . The satellite receiver  140  is connected to the Satellite Downlink Gateway  600  via a coaxial cable, which is a type of cable with a solid central conductor surrounded by an insulator that is surrounded by a cylindrical shield woven from fine wires. The shield is usually connected to electrical ground to reduce electrical interference. The Satellite Downlink Gateway  600  removes from the data the satellite protocols and frames that were added to the data by the uplink facilities before satellite transmission, yielding the data multiplexed with the authentication and session information. The Satellite Downlink Gateway  600  includes one or more Receiver Cards  625  that include a tuner, tuner control and satellite decoders. 
     The data is transmitted by the Receiver Card(s)  625  to a NDIS  630  and a WINSOCK  635  layers of software or through a MPEG-2 compliant  640  and a MCI compliant  645  layers of software. Then the data is reformed into IP packets for transmission on a local area network, or not reformed, as indicated by the multiplexed destination information in the data  650 . The data is transmitted either directly to the client computer  615  using a multicast IP protocol, or indirectly to one or more client computers  615  through the Application Services  610  via a File Capture Service  655  using a file retrieval mechanism where the data is files or a Video Replay Service  660  using a multicast video stream replay mechanism where the data is a stream. 
     The Local Program Menu Database  605  controls which data is transmitted at what time based on authentication and session information multiplexed into the data between the Satellite Downlink Gateway  600 , the Application Services  610  and one or more client computers  615 . 
     FIG. 7 illustrates the layered system architecture in accordance with a preferred embodiment. Stream data is managed at the highest level by video storage and retrieval services  700  that is supported by lower level real time transport  710  of the stream data. In comparison, data files are managed by caching and proxy services  720  that is in turn supported by Web Transport  730  Internet Protocols. All data services are supported by IP Multicast Services  740 , which are ultimately supported by satellite bitpipes  750 . 
     FIG. 8 illustrates the application services layer in accordance with a preferred embodiment. In an application of stream data, the Content Provider  800  inserts stream data  810  into the delivery subnetwork  820 . In comparison, in an application of file data, the Content Provider  830  inserts file data into the delivery subnetwork  820  where the data may be stored for a period of time and then forwarded through the delivery subnetwork  820 . 
     FIG. 9 illustrates the functional decomposition of architectural layers in accordance with a preferred embodiment. At an Application level  900  of the system function, a content provider  901  performs content insertion  910  into an Internetwork  911 , the data is transmitted through the Internetwork  911  to a destination computer  920 . At the Internetwork  911  level, the incoming data is routed by router  930  either to the subnetwork or the Internet  940 . Upon passage through either route, it is lastly routed by router  950  to the destination computer  920 . At the Subnetwork  951  level, the incoming data is received by a conditional access (CA) device  960 , and transmitted to a multiplexer (MUX)  970  in preparation for satellite transmission, then it is transmitted through a satellite  980  to an Integrated Receiver Decoder (IRD)  990 , and transmitted to a conditional access (CA) device  995  and then transmitted to the router  950 , and lastly to the destination computer  920 . 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Boundary Router In Accordance With A Preferred 
               
               
                 Embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Cisco 2509 
                 Running 11.0.11 
                   
               
               
                 Global Setup: 
                 IP Multicast Routing 
               
               
                 Protocol Setup: 
                 Static Route Distribution 
                 166.34.120.128 
               
               
                   
                 OSPF 
               
               
                 Interface Setup: 
                 Insertion Point LAN 
                 166.34.120.33-PIM 
               
               
                   
                 Segment 
                 166.34.120.255-PIM 
               
               
                   
                 Downstream LAN 
                 166.34.120.225-NO PIM 
               
               
                   
                 Segment 
               
               
                   
                 GRE Tunnel 
               
               
                   
               
             
          
         
       
     
     The source code for a downstream router in accordance with a preferred embodiment is provided below as an aid in teaching one of ordinary skill in the art to make and use the invention. 
     version 11.0 
     service udp-small-servers 
     service tcp-small-servers 
     ! 
     hostname 2509A 
     ! 
     ! 
     enable password sky 
     ip multicast-routing 
     ip dvmrp route-limit 7000 
     ! 
     interface Tunnel0 
     ip unnumbered Serial0 
     tunnel source 166.34.120.225 
     tunnel destination 166.35.252.52 
     ! 
     interface Ethernet0 
     ip address 166.34.120.33 255.255.255.224 
     ip pim dense-mode 
     ! 
     interface Serial 0   
     ip address 166.34.120.225 255.255.255.224 
     ip pim dense-mode 
     bandwidth 2000 
     no cdp enable 
     ! 
     interface Serial1 
     no ip address 
     shutdown 
     ! 
     router ospf 200 
     redistribute static subnets 
     network 166.34.0.0 0.0.255.255 area 0.0.0.0 
     ! 
     ip domain-name rch.mci.com 
     ip name-server 166.35.191.120 
     ip classless 
     ip route 0.0.0.0 0.0.0.0 166.34.120.226 
     ip route 166.34.120.128 255.255.255.224 Tunnel0 
     ip ospf name-lookup 
     ip mroute 166.34.120.128 255.255.255.224 166.34.120.32 
     no logging console 
     access-list 100 permit icmp any any 
     access-list 100 deny ip any host 224.0.0.5 
     access-list 100 permit ip host 166.34.120.226 any 
     ! 
     ! 
     line con 0 
     password sky 
     line 1 8 
     transport input all 
     line aux 0 
     transport input all 
     line vty 0 1 
     password sky 
     login 
     length 18 
     line vty24 
     password sky 
     login 
     ! 
     ntp source Serial0 
     end 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Downstream Router In Accordance With A Preferred 
               
               
                 Embodiment 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 Cisco 2509 
                 Running 11.1.6 
                   
               
               
                 Global Setup: 
                 IP Multicast Routing 
               
               
                 Protocol Setup: 
                 OSPF 
               
               
                 Interface Setup: 
                 Upstream LAN Segment 
                 166.34.120.226-PIM 
               
               
                   
                 Downstream LAN 
                 166.34.119.162-PIM 
               
               
                   
                 Segment 
               
               
                   
               
             
          
         
       
     
     The source code for a downstream router in accordance with a preferred embodiment is provided below as an aid in teaching one of ordinary skill in the art to make and use the invention. 
     version 11.1 
     service udp-small-servers 
     service tcp-small-servers 
     ! 
     hostname 2509B 
     ! 
     enable password sky 
     ! 
     ip multicast-routing 
     ip dvmrp route-limit 7000 
     ! 
     interface Ethernet 0   
     ip address 166.34.119.162 255.255.255.240 
     ip pim dense-mode 
     ! 
     interface Serial0 
     ip address 166.34.120.226 255.255.255.224 
     ip pim dense-mode 
     bandwidth 2000 
     clockrate 2000000 
     ! 
     interface Serial1 
     no ip address 
     bandwidth 1500 
     shutdown 
     clockrate 2000000 
     ! 
     router ospf 200 
     network 166.34.0.0 0.0.255.255 area 0 
     ! 
     ip domain-name rch.mci.com 
     ip name-server 166.35.191.120 
     ip classless 
     no logging console 
     access-list 100 permit icmp any any 
     ! 
     line con 0 
     password sky 
     line 1 8 
     line aux 0 
     line vty 0 
     password sky 
     login 
     length 18 
     line vty 1 4 
     password sky 
     login 
     ! 
     ntp clock-period 17180064 
     ntp source Ethernet0 
     end 
     While the invention is described in terms of preferred embodiments in a specific system environment, those skilled in the art will recognize that the invention can be practiced, with modification, in other and different hardware and software environments within the spirit and scope of the appended claims.