Patent Publication Number: US-2006020717-A1

Title: Vehicle active network and device

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates generally to the field of communication systems for vehicles such as automobiles and trucks, and more particularly, to communicatively coupling devices within the vehicle.  
      2. Description of the Related Art  
      Microprocessor technology has greatly improved the efficiency, reliability and safety of the automobile. Microprocessor devices have enabled airbags, anti-lock brakes, traction control, adaptive suspension and power train control just to name a few of the areas where processing technology has literally transformed the automobile. These systems, first provided by manufacturers only on the most expensive luxury and performance automobiles, are now common and even standard equipment on the most affordable economy models. Soon, control-by-wire applications will become equally commonplace. For example, throttle-by-wire has been successfully implemented on a number of vehicle platforms. Steer-by-wire and brake-by-wire applications are not far behind. Alternative fuel vehicles, including fuel cell vehicles, electric and hybrid vehicles will require still more sophisticated control applications, and hence still more processing capability.  
      The automobile is simultaneously being enhanced by information technology. Satellite navigation systems, voice and data communications, and vehicle telemetry systems inform the driver, entertain the passengers and monitor vehicle performance. These systems can provide driving directions, identify points of interest along the driver&#39;s route, remotely diagnose and/or predict vehicle problems, unlock the doors, disable the vehicle if stolen or summon emergency personnel in the event of an accident.  
      The growing amount and level of sophistication of vehicle oriented information technology presents the challenge to the automotive engineer to implement and integrate these technologies with existing and emerging vehicle systems in an efficient manner. Current design philosophy centers on the incorporation of one or more vehicle communication bus structures for interconnecting the various control elements, sensors, actuators and the like within the vehicle. The design of these bus structures is often driven by compliance with governmental regulations such as second-generation on-board diagnostics (OBD-II) and federal motor vehicle safety standards (FMVSS). These structures offer limited ability to adapt new technology to the vehicle. Moreover, given the typical four-year design cycle and ten-year life cycle of an automobile, the technology within a vehicle may become significantly obsolete even before the vehicle is brought to market, and the bus architecture leaves the owner little ability to adapt new technology to the vehicle. Notwithstanding these limitations, the bus architecture offers a generally reliable, relatively fast platform for linking electronic devices and systems within the vehicle.  
      To link vehicle system technologies with vehicle information technologies, there has been proposed to incorporate a network architecture within the vehicle. For example, published Patent Cooperation Treaty (PCT) application number WO 00/77620 A2 describes an architecture based on the Ethernet wherein devices within the vehicle are coupled to the network. This publication describes a network including a cable backbone to which the devices are coupled and a network utility for controlling communications between the devices over the network. Important to note is that the proposed network does not integrate the vehicle systems, but instead is adapted to provide a platform for adding information technologies, such as pagers, personal digital assistants, navigations, etc. technologies to the vehicle. The power train, suspension, braking and airbag systems, as examples, utilize a vehicle bus for data communications, and these systems operate autonomously of the network described in the publication. A bridge or gateway is provide to couple the vehicle bus to the network as a device or client allowing data sharing between the bus and the network, but the data communication needs of the vehicle systems are not serviced by the network. A reason that these systems are designed to operate autonomously of the described network is that they have time critical, system critical data requirements that cannot be met by the network structure described. Additionally, the network described in the publication suffers from numerous single points of failure, such as if the cable backbone is disrupted or the network utility fails.  
      Thus there is a need for an architecture for automotive electronic systems that facilitates the efficient, reliable integration of in-vehicle electronic technologies and plug-and-play upgradeability. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The invention is described in terms of the several preferred embodiments set out fully below and with reference to the following drawings in which like reference numerals are used to refer to like elements through out.  
       FIG. 1  is a block diagram illustration of an embodiment of a vehicle active network according to the invention.  
       FIG. 2  is a block diagram illustration of the vehicle active network shown in  FIG. 1  illustrating multiple communication path capability of the vehicle active network.  
       FIG. 3  is a block diagram illustration of an alternate embodiment of a vehicle active network.  
       FIG. 4  is a graphic illustration of an embodiment of the vehicle active network according to the invention.  
       FIG. 5  is a graphic illustration of a portion of the vehicle active network illustrated in  FIG. 4  illustrating propagation of timing information throughout the network.  
       FIG. 6  is a graphic illustration of an alternate embodiment of a three-dimensional vehicle active network.  
       FIG. 7  is a graphic illustration of an alternate embodiment of a vehicle active network according to the invention incorporating a No-Go zone.  
       FIG. 8  is a graphic illustration of an embodiment of a vehicle active network according to the invention providing packet redundancy.  
       FIG. 9  is a schematic illustration of an embodiment of an active network element according to the invention.  
       FIG. 10  is a schematic illustration of an embodiment of a vehicle active network including a device forming a portion of the vehicle active network.  
       FIG. 11  is a schematic illustration of an alternate embodiment of a vehicle active network including a device forming a portion of the vehicle active element.  
       FIG. 12  is a schematic illustration of an alternate embodiment of a vehicle active network including a device forming a portion of the vehicle active element.  
       FIG. 13  is a schematic illustration of an alternate embodiment of a vehicle active network including a device forming a portion of the vehicle active element.  
       FIG. 14  is a block diagram illustration of linked active networks according to an alternate embodiment of the invention.  
       FIG. 15  is a block diagram illustration of linked active networks according to an alternate embodiment of the invention.  
       FIG. 16  is a graphic illustration of an alternate embodiment of a vehicle active network according to the invention incorporating a core portion.  
       FIG. 17  is a graphic illustration of an alternate embodiment of a vehicle active network illustrating adaptable scalability.  
       FIG. 18  is a graphic illustration of an alternate embodiment of a vehicle active network illustrating adaptable scalability.  
       FIG. 19  is a block diagram illustration of a topology for a vehicle active network according to a preferred embodiment of the invention.  
       FIG. 20  is a block diagram illustration of a topology for a vehicle active network according to an alternate preferred embodiment of the invention.  
       FIG. 21  illustrates various data packets that may be adapted for use with a vehicle active network according to the preferred embodiments of the invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      An architecture for automotive functional systems according to the invention is based upon inter-networking and computing principles. The architecture incorporates a vehicle active network for communicatively coupling devices within the vehicle. Device operation is independent of the interface of the device with the active network. Additionally, the architecture of the active network provides one or more levels of communication redundancy. The architecture provides for the total integration of vehicle systems and functions, and permits plug-and-play device integration, scalability and upgradeability.  
      The active network may include a plurality of communicatively coupled active elements, which permit communication between devices coupled to the active network without a network utility or arbiter. The active elements enable multiple simultaneous communication paths between devices within the vehicle. The multiple simultaneous communication paths may include a variety of potential paths among the active elements, including, for example, alternative paths responsive to network status, redundant paths or even a loop having a loop data rate different from a path data rate of other communication paths.  
      The active network may be based upon packet data principles and implement any suitable packet data transmission protocol. Suitable packet data protocols include, but are not limited to, transmission control protocol/Internet protocol (TCP/IP), asynchronous transfer mode (ATM), Infiniband, and RapidIO. Each of these protocols, when implemented in an active network according to the various embodiments of the invention, permits one or more levels of redundant communication capability to ensure reliable data transfer while permitting active system diagnostics and fault tolerance.  
      The active network may incorporate a fabric of active network elements communicatively coupling the devices. The fabric permits multiple simultaneous peer-to-peer communications. The active network elements may be arranged in, for example, an array topology, a multi-drop topology, or an asymmetric topology. Furthermore, the architecture may incorporate one or more levels of wireless communication. For example, the architecture supports peer-to-peer, one-to-many broadcast, many-to-many broadcast, intra-network and inter-network communications, device to network, vehicle-to-vehicle and vehicle to remote station wireless communications.  
      Many additional advantages and features of the invention will be apparent from the description of the various preferred embodiments. At the outset it is important to point out that the invention is described in terms of embodiments implemented within a vehicle, or more particularly, an automobile. The terms vehicle and automobile as used herein may include automobiles, trucks, buses, trailers, boats, airplanes, trains and the like. Therefore, references to vehicle or automobile apply equally to virtually any type of commercially available vehicle.  
       FIG. 1  illustrates a vehicle  10  including an active network  12  to which various vehicle devices  14 - 20  are coupled via respective interfaces  22 - 28 . The devices may be sensors, actuators and processors used in connection with various vehicle functional systems and sub-systems, such as, but not limited to, control-by-wire applications for throttle, braking and steering control, adaptive suspension, power accessory control, communications, entertainment, and the like.  
      The interfaces  22 - 28  are any suitable interface for coupling the particular device to the active network  12 , and may be wire, optical, wireless or combinations thereof. The interfaced device is particularly adapted to provide one or more functions associated with the vehicle. These devices may be data producing, such as a sensor, data consuming, such as an actuator, or processing, which both produces and consumes data. Of course, an actuator, typically a data-consuming device, may also produce data, for example where the actuator produces data indicating it has achieved the instructed state, or a sensor may consume data, for example, where it is provided instructions for the manner of function. Data produced by or provided to a device, and carried by the active network  12 , is independent of the function of the device itself. That is, the interfaces  22 - 28  provide device independent data exchange between the coupled device and the active network  12 .  
      The active network  12  defines a plurality of communication paths  30  between the devices. The communication paths  30  permit multiple simultaneous peer-to-peer, one-to-many, many-to-many, etc. communications between the devices  14 - 20 . Illustrated in  FIG. 1 , a communication path  32 , illustrated by the bold arrowed lines, may be formed between device  14  and device  20 . This is not the only communication path available for communications between devices  14  and  20 . Illustrated in  FIG. 2 , a path  34  may also couple devices  14  and  20 . During operation of the vehicle  10 , data exchanged between devices  14  and  20  may utilize paths  32  and  34  or other paths between the devices. In operation, a single path may carry all of a single data communication between the device  14  and the device  20 , or several communication paths may carry portions of the data communication. Subsequent communications may use the same path or other paths as dictated by the then state of the active network  12 . This provides reliability and speed advantages over bus architectures that provide single communication paths between devices, and hence are subject to failure with failure of the single path. Moreover, communications between other of the devices  14 - 20  may occur simultaneously using the communication paths  30 .  
      The active network  12  may comply with transmission control protocol/Internet (TCP/IP), asynchronous transfer mode (ATM), Infiniband, RapidIO, or other packet data protocols. As such, the active network  12  utilizes data packets, having fixed or variable length, defined by the applicable protocol. For example, if the active network  12  uses asynchronous transfer mode (ATM) communication protocol, ATM standard data cells are used.  
      The devices  14 - 20  need not be discrete devices. Instead, the devices may be systems or subsystems of the vehicle and may include one or more legacy communication media, i.e., legacy bus architectures such as CAN, LIN, FLEXRAY or similar bus structures. In such embodiments, the respective interface  22 - 28  may be configured as a proxy or gateway to permit communication between the active network  12  and the legacy device  14 - 20 . Alternatively, and referring to  FIG. 3 , the device  18  of the vehicle  10  is communicatively coupled via an interface  35  to a bus architecture  33 . The bus architecture  33  is then coupled via the interface  26  to the active network  12 . The bus architecture may be a CAN, LIN, FLEXRAY or similar bus structure.  
      Referring to  FIG. 4 , an active network  36  in accordance with an alternate embodiment of the invention includes a fabric  38  of active network elements  40  communicatively coupling a plurality of devices  44 - 50  via respective interfaces  52 - 58 . Connection media  42  interconnects the active network elements  40 . The connection media  42  may be bounded media, such as wire or optical fiber, unbounded media, such as free optical or radio frequency, or combinations thereof. In addition, the term active network element is used broadly in connection with the definition of the fabric  38  to include any number of intelligent structures for communicating data packets within the active network  36  without an arbiter or other network controller and may include: switches, intelligent switches, routers, bridges, gateways and the like. Data is thus carried through the network  36  in data packet form guided by the active elements  40 .  
      The cooperation of the active elements  40  and the connection media  42  define a plurality of communication paths between the devices  44 - 50  that are communicatively coupled to the active network  36 . For example, a route  60  defines a communication path from device  44  to device  50 . If there is a disruption  61  along the route  60  inhibiting communication of the data packets from the device  44  to the device  50 , for example, if one or active elements are at capacity or have become disabled or there is a disruption in the connection media joining the active elements along the route  60 , a new route, illustrated as route  62 , can be used. Route  62  may be dynamically generated or previously defined as a possible communication path, to ensure the communication between the device  44  and the device  50 .  
      In some applications, it may be necessary to provide synchronized activity, which requires timing information be available within the active network.  FIG. 5  illustrates a portion  80  of an active network that includes a fabric  82  of active elements  84 . Connection media  86  interconnects the active elements  84 . Active element  88  is defined as a root node or a root element. A spanning tree algorithm may be used in association with the active network to define the plurality of communication paths available within the active network. The plurality of communication paths may be defined by the spanning tree algorithm during an initial configuration, or may be defined by a running of the spanning tree algorithm during each power on cycle or by other periodic running of the spanning tree algorithm. Timing may be propagated from the root node element  88  in the form of timing messages  90  from the root node, active element  88 , to each of the active elements  84  via the plurality of communication paths. From the root node, the spans of connecting media  86  between each active element  84 , and hence any delay in clock cycles in such spans, is known, and therefore from the root node precise timing may be established at each of the active elements  84  and likewise at each of the devices coupled to the active network. Timing within the active network may be absolute, or may be differential.  
      Differential, or relative, timing is possible based on the configuration of the active network and the data packets. The point-to-point connections within the active network allow accurate calculation of time to traverse the network. Thus, one is able to know when a packet was generated based upon the point in the network it started at, the route it took, and when it arrived at the current point. The time the packet was generated is thus, “now” minus x units of time, where the x units of time is the known time based on the route. In this scenario for timing, a central or root node may not be required.  
      Timing information within the network may degrade, for example as the result of clock skew. Having the root node send periodic timing messages refreshes the timing information. Data packets communicated within the active network may also contain timing information allowing individual devices to update the timing information on an ongoing basis. Of course, the data packets may also contain timing information to indicate when certain activities are to take place, or to indicate the freshness of the information. Other methods for establishing timing within the active networks apart from the root node concept may be employed.  
       FIG. 6  illustrates an active network  100  including a fabric  102  of active network elements  104  arranged in a three-dimensional configuration. Connection media  106  communicatively couples the active network elements  104 . The connection media may be wire, optical, radio frequency or combinations thereof. The three-dimensional configuration of fabric  102  may be used in connection with virtually any of the embodiments of an active network in accordance with the invention, and demonstrates the flexibility and scalability of such active networks.  
       FIG. 7  illustrates the active network  36  ( FIG. 4 ) modified to include a No-Go zone  64 . The No-Go zone  64  exclusively reserves a portion of the fabric  38 , namely the active elements and connection media contained within the No-Go zone  64 , for communication of data between device  46  and the device  48 . The No-Go zone  64  may reserve a sufficient portion of the fabric  38  to provide a plurality of possible communication paths between the devices  46  and  48 , or may reserve a single communication path. The No-Go zone  64  may be configured to carry data packets to/from the device  46  and to/from the device  48  to the exclusion of any other data packets. Alternatively, the No-Go zone  64  may be available for communication of data packets to/from any device provided that data packets to/from devices  46  and  48  have transmission priority. Still further, criteria may be established relating to the use of the No-Go zone  64  to transmit data to/from devices other than devices  46  and  48 . For example, where a fault in the switch fabric requires use of the No-Go zone  64  or where the non-exclusive use of the No-Go zone  64  does not exceed a threshold percentage of the overall capacity of the No-Go zone.  
      The No-Go zone  64  provides assured communication capability between the devices associated with the No-Go zone  64 . For example, if the devices  46  and  48  are associated with a steer-by-wire application, proper vehicle function requires that the data for this application be transmitted to the appropriate devices. Providing priority to the data packets associated with the steer-by-wire application and transmitting them within the switch fabric  38  generally may not sufficiently ensure the data packets are timely delivered. However, reserving a portion of the switch fabric  38 , i.e., the No-Go zone  64 , provides the advantages of a hard connection between the devices while preserving the flexibility of utilizing the entire switch fabric  38 , if needed, should a fault occur within the No-Go zone  64 . While described in connection with the active network  36  illustrated in  FIG. 4 , the concept of the No-Go zone may be applied to any of the active network architectures contemplated by the invention, including those shown in the embodiments illustrated in  FIGS. 1 and 2 . Furthermore, while the No-Go zone  64  is shown as two-dimensional in  FIG. 7 , the No-Go zone  64  may correspond in dimension to that of the fabric of active network elements. Also, the No-Go zone  64  may be dynamically redefined during operation of the vehicle.  
      The multi-path architecture of the active network  12  and the active network  36  permits fault tolerance and fault diagnosis to be easily incorporated via data stream replication. Fault tolerance may be provided using replicated data packets sent along the same communication path or multiple data paths. An embodiment wherein data packets are replicated and transmitted along redundant paths is illustrated in  FIG. 8 , which again depicts the active network  36 . Device  46  is communicatively coupled to the fabric  38  by interface  54 . At switch element  66 , data packets received from the device  44  are replicated, forming two streams of data packets (data streams). Of course more than two data streams may be generated, and additional data streams add additional levels of redundancy. The data streams are transmitted from the device  44  to the device  50  via different communication paths, and paths  68  and  70  are two of the numerous possible paths that may be formed in the switch fabric  38  from the device  46  to the device  50 . Not all data packets need to travel on the same path, and the paths  68  and  70  merely illustrate the concept of the redundant paths. The redundancy provided by the two data streams (replicated data packets) enhances reliability because a failure or disruption of one of the streams does not completely interrupt transmission of the data between the devices. Moreover, by monitoring receipt of the data streams at the device  50  it is possible to determine whether a fault exists in the fabric  38 , and to isolate the fault to a region of the fabric  38 . That is, the fault will lie on one of the two paths  68  and  70  on which the transmission of the respective data stream failed. Additionally, performance of the fabric  38  may be measured based upon time of arrival data of the two data streams.  
       FIG. 9  illustrates an active element  110  that may be used in connection with the fabric  38 . To illustrate the functionality and the adaptability of the active element  110 , it is shown to include a plurality of input ports  112 , output ports  114  and input/output ports  116  and  118 . Various configurations of the active element  110  having more or fewer ports may be used in an active network depending on the application. The active element  110  may further include a processor  120  coupled with a memory  122 . The processor  120  includes a suitable control program for effecting the operation of the active element  110  for coupling inputs to outputs in order to transmit data packets within fabric  38 .  
      The simplex input ports  112  and output ports  114  may be adapted for optical media, while the duplex input/output ports  116  and  118  may be adapted for electrical media. Additionally, the active element  110  may include a radio frequency (RF) transceiver  124  for RF transmission of data packets to other switch elements within the switch fabric  38  and to switch elements of other active networks, for example active networks located in nearby vehicles. The switch element  110  may be an assembly of circuit components or may be formed as a single integrated circuit device.  
       FIG. 10  illustrates an alternate embodiment providing fault tolerance and fault detection. As illustrated in  FIG. 8 , a single interface  52  couples the device  44  to the fabric  38 . Failure of the interface  52  would result in the device  44  becoming uncoupled from the fabric  38 . Referring then to  FIG. 10 , a portion  130  of a fabric, such as fabric  38 , includes a plurality of active elements  132  communicatively coupled by connecting media  134 . A device  136  is communicatively coupled to the portion  130 . The device  136  includes an active element  138  integral to the device, and providing a plurality of input/output ports. The plurality of input/output ports, three of which are illustrated in  FIG. 10 , couple to interfaces  140 ,  142  and  144 . The interfaces  140 ,  142  and  144  are communicatively coupled to switch elements  146 ,  148  and  150 , respectively, of the portion  130 . In this manner, the device  136  is communicatively coupled via a plurality of communication paths to the portion  130  of the fabric. Data streams may be communicated along each of the communication paths to a destination device. This adds reliability by providing redundant paths from the device  136  to the fabric. It is also possible to determine the existence and locations of faults and fabric performance by monitoring the receipt of the data streams at the destination device along each of the plurality of communication paths.  
      In  FIG. 11 , the device  136  of  FIG. 10  has been replaced by a sub-system  152 . The sub-system  152  includes a plurality of devices  154 - 158  that are coupled via interfaces  160 - 164 , respectively, to an active element  166  within the device  136 . The active element  166  is then coupled to the portion  130  of the fabric. The active element  166  may couple data streams from one or more of the devices  160 - 164  to the portion  130 . Moreover, the data streams may be coupled on multiple communication paths  140 - 144  to the portion  130 .  
      In  FIG. 12 , the device  170  includes redundant elements  172  and  174 . That is, each of elements  172  and  174  are designed to provide the required function of the device  170 . In addition to providing a vehicle-related function, the device  170  also includes device elements  176  and  178 , i.e., active network elements integrated within the device  170  which also form a portion of the active network. The device elements  176  and  178  are coupled to active elements  146  and  148  of the portion  130 . The device elements  172  and  174  are also coupled to each of the active elements  176  and  178  within the device  170  via connection media  184 . Redundant function and redundant coupling of the device  170  to the fabric is provided by this arrangement ensuring that failure of either device elements  172  or  174  and/or failure of active elements  176  and  178  and/or active elements  146  and  148  will not cause a loss of the function of the device  170 .  
      In  FIG. 13 , the system  180  includes devices  182 ,  184  and  186 . Each of devices  182 - 186  may be designed to provide the same function, i.e., triple redundancy, or may provide separate functions. The system  180  also includes device elements  188 - 192 . The device elements  188 - 192  are respectively coupled to active elements  146 - 150  of the portion  130 . The device elements  188 - 192  are also coupled to each other by connection media  183 - 187 . Thus, triply redundant function and coupling is provided.  
       FIG. 14  illustrates wireless coupling of active networks across vehicles. A first vehicle  200  includes an active network  202  including a plurality of active elements, two of which are indicated as  204  and  206 . All of the active elements, including the elements  204  and  206 , are communicatively coupled via media  208 . A second vehicle  210  includes an active network  212  including a plurality of active elements, two of which is indicated as  214  and  216 . All of these active elements, including the active elements  214  and  216 , are communicatively coupled via media  218 . Each of the active elements  204  and  206  includes wireless communication capability, and similarly, each of the active elements  214  and  216  includes wireless communication capability. For example, the active elements  204 ,  206  and  214 ,  216  may incorporate a radio frequency transceiver permitting these devices to communicate via radio frequency transmissions.  
      As shown in  FIG. 13 , the active element  204  is communicatively coupled with the active element  214  via radio frequency transmissions  220 , and the active element  206  is communicatively coupled with the active element  216  via radio frequency transmissions  222 . In this manner, multiple vehicles may be linked via the active elements disposed within the active networks. Linking the active networks in this manner effectively expands the active networks of both vehicles, and hence the number of communication paths available to link devices in any of the linked vehicles. An automobile may be communicatively coupled to a trailer that it is towing. Two vehicles traveling together can be linked in order to exchange messages, vehicle functional data, entertainment programming, etc. For example, passengers in linked vehicles may jointly play electronic games or watch video programming. A vehicle disabled because of the failure of one or more devices may be rendered operable in tandem with a rescue vehicle to which it is linked by using the functioning devices in the rescue vehicle to provide the function to both. Similarly, if a device becomes isolated in a vehicle because of a failure of a portion of the active network, communication to the device may be reestablished using a linked surrogate vehicle to provide communication paths to the isolated device.  
      While all of the active elements forming an active network may include radio frequency transmission capability, for inter-vehicle linking of active networks, as opposed to intra-vehicle linking of active elements, linking may be limited to selected ones of the active elements. These selected active elements may include security, authentication, encryption, etc. capability. Thus, while an active element within the vehicle may wirelessly link to virtually any other active element within the active network, active networks may be limited to linking via particular active elements. Moreover, the types and quantities of data exchanged may be limited. For linked active networks with low security and lacking encryption, the link may be limited to transmission of non-identifying vehicle operating data. For example, in a one-to-many broadcast application, a vehicle&#39;s headlights may be modulated to signal on-coming traffic about a traffic event. In this case, the signaling vehicle&#39;s headlights are a first wireless interface, and a photo-diode or similar device on the receiving vehicle is a second wireless interface. Many vehicles may report the event in this or similar fashion, and many other vehicles may receive the reported information thus establishes a many-to-many multicast.  
      One of the many applications of linking of active networks is the ability to upgrade systems by upgrading software within vehicles without having the vehicle return to a repair facility. Vehicles may identify upgraded software via the linking of active networks and request a copy of the upgraded software be communicated to the active network. While this process may be made seamless and transparent to the vehicle operator, safeguards may be included permitting the vehicle operator to authorize any such sharing and implementation of such upgraded software. Navigation, entertainment, and other similar program data may be shared via the inter-vehicle linking of active networks.  
       FIG. 15  illustrates an alternate arrangement for wireless coupling of active networks across vehicles. A first vehicle  240  includes an active network  242  including a plurality of active elements. Coupled to the active network  242  is a wireless interface  244 . A second vehicle  246  includes an active network  248  including a plurality of active elements. The second vehicle  246  also includes a wireless interface  250 . Each wireless interface  244  and  250  includes a suitable transceiver, such as an optical or radio frequency transceiver, and each may also include processing capability and memory. The wireless interfaces  244  and  250  arbitrate the wireless linking of the active networks  242  and  248  providing required authentication, security and encryption.  
      Referring now to  FIG. 16 , the active network  36  ( FIG. 4 ) is adapted to include a core network portion  260 . The core network portion  260  includes a plurality of core active elements  262 . The core active elements  262  are communicatively coupled only to other active elements, whether core active elements  262  or other, peripheral active elements  40  forming a peripheral portion of the active network  36 . High-speed media  264  provides interconnections between core active elements  262 . In this manner, data may be transferred through the core network portion  260  at a first, high data rate, and transferred to/from devices coupled to the active network  36  at a second, slower data rate. Alternatively, the interconnection of the core active elements may be made using multiple communication links providing enhanced communication capacity. Devices are coupled to the active network via the peripheral active elements.  
       FIG. 17  illustrates the active network  36  adapted to include “fat pipe” members  270  and  272 . Fat pipe members  270  and  272  provide direct coupling of the active element  274  to the active element  276  and the active element  278  to the active element  280 , respectively. The fat pipe members  270  and  272  may be, and generally are high speed data carrying members adapted for particular applications, and may be particularly adapted to provide scalability in an after-market arrangement, such as coupling a DVD player to a video display. In that regard, the original equipment active elements may be replaced with the active elements  274 - 280  capable of handling the higher data capacity of the fat pipe members  270  and  282 . Alternatively, the fat pipe members  270  and  272  may provide scalability in original equipment applications. For example, the fabric  38  may be configured for a base level of vehicle options, while premium options are provided by adding the fat pipe members  270  and  272 .  
       FIG. 18  illustrates the active network  36  adapted with additional active elements  290  and  292  and connection media  294 - 302  coupling the active elements  290  and  292  to the active network  36 .  FIG. 18  illustrates the manner in which active networks in accordance with the invention may be expanded, by adding connection media and additional active elements to the fabric as needed. If necessary, existing active elements may be replaced with active elements having a sufficient number of ports to be able to add the connection media  294 - 302 . Moreover, the connection media  294 - 302  may have a higher data capacity than the existing connection media  294 - 302 . As will be further appreciated from the embodiments of the invention illustrated in  FIGS. 17 and 18 , the fabric including either the “fat pipe” members or the additional active elements does not need to have a uniform configuration, and may have an asymmetric configuration.  
       FIGS. 19 and 20  illustrate alternative active network configurations. In  FIG. 19 , an active network  310  includes a ring  312  of interconnected active network elements (not depicted). A plurality of devices  314 - 322  is communicatively coupled by interfaces  324 - 332 , respectively to the ring  312  in a multi-drop arrangement. Additionally, devices  320  and  322  are coupled for peer-to-peer communications by communication link  344 . Communication link  334  may be formed of any suitable media, including wire, optical, radio frequency or combinations thereof. The device  320  therefore may communicate with the device  322  via the network  312  or directly via the peer communication link  334 .  
      In  FIG. 20 , an active network  340  includes a backbone  342  of interconnected active elements to which a plurality of devices  344 - 352  is communicatively coupled by interfaces  354 - 362 , respectively to the backbone in a multi-drop arrangement. Additionally, devices  348  and  352  are coupled for peer-to-peer communications by communication link  364 . Communication link  364  may be formed of any suitable media, including wire, optical, radio frequency or combinations thereof. The device  348  therefore may communicate with the device  352  via the network  340  or directly via the peer communication link  364 .  
       FIG. 21  illustrates several data packet configurations that may be used in connection with active networks according to the embodiments of the invention. As described, the active networks may be configured to operate in accordance with TCP/IP, ATM, RapidIO, Infiniband and other suitable communication protocols. These data packets include structure to conform to the standard required. A typical data packet, such as the data packet  400  includes a header portion  402 , a payload portion  404  and a trailer portion  406 . As described herein, the active network and the network elements forming the active network may contain processing capability. In that regard, a data packet  410  includes along with a header portion  412 , payload portion  414  and trailer portion  416  an active portion  418 . The active portion may cause the network element to take some specific action, for example providing alternate routing of the data packet, reconfiguration of the data packet, reconfiguration of the network element, or other action, based upon the content of the active portion. The data packet  420  includes an active portion  428  integrated with the header portion  422  along with a payload portion  424  and a trailer portion  426 . The data packet  430  includes a header portion  432 , a payload portion  434  and a trailer portion  436 . An active portion  438  is also provided, disposed between the payload portion  434  and the trailer portion  436 . Alternatively, as shown by the data packet  440 , an active portion  442  may be integrated with the trailer portion  444  along with a payload portion  446  and a header portion  448 . The data packet  450  illustrates a first active portion  460  and a second active portion  458 , wherein the first active portion  460  is integrated with the header portion  452  and the second active portion  458  is integrated with the trailer portion  456 . The data packet  450  also includes a payload portion  454 . Certainly numerous other arrangements of the data packets for use with the present invention may be envisioned.  
      The data, and particularly the data packets, sent within the active network may be encrypted. The encryption function may be provided by the interface of the device to the active network, e.g., interfaces  22 - 28  ( FIG. 1 ) or by the active network element of the active network to which the device is coupled. Data may be encrypted to ensure that it is not altered as it is communicated within the active network, which may be important for the proper function of various safety systems of the vehicle or to ensure compliance with governmental regulation. A suitable public or private key encryption algorithm may be employed, and the data may be encrypted before being packetized or the individual data packets may be encrypted after packetization. Moreover, detecting errors in the data upon decrypting may provide an indication of an error or fault condition in the active network along the route utilized by data packet, which caused the corruption of the data packet.  
      The active portion of the data packet may represent a packet state. For example, the active portion may reflect a priority of the data packet based on aging time. That is, a packet initially generated may have a normal state, but for various reasons, is not promptly delivered. As the data packet ages as it is routed through the active network, the active portion can monitor time since the data packet was generated or time when the packet is required, and change the priority of the data packet accordingly. The packet state may also represent an error state, either of the data packet or of one or more elements of the active network. The active portion may also be used to messenger data unrelated to the payload within the network, track the communication path taken by the data packet through the network, provide configuration information (route, timing, etc.) to active elements of the active network, provide functional data to one or more devices coupled to the active network or provide receipt acknowledgment.  
      The invention has been described in terms of several embodiments, including a number of features and functions. Not all features and functions are required for every embodiment of the invention, and in this manner the invention provides an adaptable, fault tolerant, active network architecture for vehicle applications. The features discussed herein are intended to be illustrative of those features that may be implemented; however, such features should not be considered exhaustive of all possible features that may be implemented in a system configured in accordance with the embodiments of the invention.