Patent Publication Number: US-7912001-B2

Title: Methods, systems, and products for a metering application

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit under 35 U.S.C. §119 (e) of U.S. Provisional Application No. 60/602,147, filed Aug. 17, 2004, which is incorporated herein by reference in its entirety. This application is also a continuation-in-part of U.S. application Ser. No. 10/719,270, filed Nov. 21, 2003, which claims benefit under 35 U.S.C. §119 (e) of U.S. Provisional Application No. 60/470,650, filed May 15, 2003, and incorporated herein by reference in its entirety. 
    
    
     NOTICE OF COPYRIGHT PROTECTION 
     A portion of the disclosure of this patent document and its figures contain material subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, but otherwise reserves all copyrights whatsoever. 
     BACKGROUND 
     This application generally relates to electrical computers and digital processing systems, to interactive video distribution systems, and to multiplex communications. This application, more particularly, relates to computer-to-computer protocol implementing, to computer network managing, to computer-to-computer data routing, to a video distribution system with upstream communication, and to pathfinding or routing. 
     Communications network service providers need bandwidth and quality of service configuration options. As more and more customers desire greater access to broadband services, service providers need network configuration options that can be customized on a per-subscriber and a per-application level. These configuration options would make the network more manageable by allowing dynamic bandwidth and quality of service determinations. What is needed, then, are schemes that dynamically adjust bandwidth and quality of service to reflect the dynamic needs of the communications network. 
     SUMMARY 
     The aforementioned problems, and other problems, are reduced, according to the exemplary embodiments, by a metering application. This metering application is a network management tool that dynamically adjusts bandwidth on a per-customer level. This metering application comprises methods, computer systems, and computer products that enforce a rate limit for data traffic. The data traffic may include any packetized stream of data, such as video, images, voice (e.g., Voice-Over Internet Protocol), Internet Protocol television, and any other packetized data. The metering application identifies a stream of data packets flowing though a server to a downstream end user. The metering application classifies the unidirectional stream according to a rate class, with each rate class having an associated rate limit. Each rate limit specifies a maximum bit rate at which the unidirectional stream may flow through the server. The end-user customer typically subscribes to a class of service. Each class of service has an associated maximum bit rate at which streams of data may flow downstream to the end-user customer. If the customer subscribes to a class of service having a high rate limit, the customer can receive/download data at high bit rates. If, however, the customer subscribes to a class of service having a low rate limit, the customer can only receive/download data at low bit rates. The metering application, then, polices and enforces the rate limit. When the customer requests a stream of data having an actual bit rate that exceeds the maximum bit rate permitted for the customer&#39;s rate class, the metering application decides whether the rate limit must be enforced. If the metering application enforces the rate limit, the metering application will discard packets of data to reduce the bit rate of the requested stream. 
     According to the exemplary embodiments, methods, systems, and products are disclosed for enforcing a rate limit for data traffic. One method identifies a unidirectional stream of data packets flowing though a server to a downstream end user. The unidirectional stream is classified according to a rate class, with each rate class having an associated rate limit. Each rate limit specifies a maximum bit rate at which the unidirectional stream may flow through the server. When the actual bit rate of the unidirectional stream exceeds the maximum bit rate permitted for the associated rate class, packets of data are discarded to reduce the bit rate. 
     Other embodiments describe a system for system for enforcing a rate limit for data traffic. This system comprises a metering application stored in a memory device. The system also comprises a processor, and the processor communicates with the memory device. The metering application identifies a unidirectional stream of data packets flowing though the system to a downstream end user. The metering application classifies the unidirectional stream of data packets according to a rate class. Each rate class has an associated rate limit, with each rate limit specifying a maximum bit rate at which the unidirectional stream may flow through the system. The metering application discards packets of data within the unidirectional stream of data packets to reduce a bit rate until the bit rate is less than or equal to the maximum bit rate permitted for the associated rate class. 
     Still more embodiments describe a computer program product for enforcing a rate limit for data traffic. The computer program product comprises a computer-readable medium and a metering application stored on the computer-readable medium. The metering application comprises computer-readable instructions for enforcing a rate limit for data traffic. The computer-readable instructions identify a unidirectional stream of data packets flowing though a server to a downstream end user. The unidirectional stream is classified according to a rate class, with each rate class having an associated rate limit. Each rate limit specifies a maximum bit rate at which the unidirectional stream may flow through the server. When the actual bit rate of the unidirectional stream exceeds the maximum bit rate permitted for the associated rate class, packets of data are discarded to reduce the bit rate. 
     Other systems, methods, and/or computer program products according to embodiments will be or become apparent to one with skill in the art upon review of the following drawings and detailed description. It is intended that all such additional systems, methods, and/or computer program products be included within this description, be within the scope of the present invention, and be protected by the accompanying claims. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       These and other features, aspects, and advantages of the embodiments are better understood when the following Detailed Description is read with reference to the accompanying drawings, wherein: 
         FIGS. 1-3  are schematics illustrating the exemplary embodiments; 
         FIG. 4  is a schematic illustrating another scheme for enforcing rate limits, according to more exemplary embodiments; 
         FIGS. 5-7  are schematics illustrating schemes for enforcing rate limits when two or more streams are requested, according to yet more exemplary embodiments; 
         FIG. 8  is a schematic illustrating stripping and discarding information to enforce rate limits, according to more exemplary embodiments; 
         FIG. 9  is a schematic illustrating multi-layer encoding for enforcing rate limits, according to still more exemplary embodiments; 
         FIG. 10  is a schematic illustrating degradation of television service to enforce rate limits, according to even more exemplary embodiments; 
         FIG. 11  is a schematic illustrating a delta definition stream to enforce rate limits, according to more exemplary embodiments; 
         FIG. 12  depicts another possible operating environment for the exemplary embodiments; and 
         FIGS. 13 &amp; 14  are flowcharts illustrating a method for enforcing rate limits, according to still more exemplary embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Exemplary embodiments will now be described more fully hereinafter with reference to the accompanying drawings, in which exemplary embodiments are shown. The exemplary embodiments, however, may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. These embodiments are provided so that this disclosure will be thorough and complete and will fully convey the scope of the invention to those of ordinary skill in the art. Moreover, all statements herein reciting embodiments of the invention, as well as specific examples thereof, are intended to encompass both structural and functional equivalents thereof. Additionally, it is intended that such equivalents include both currently known equivalents as well as equivalents developed in the future (i.e., any elements developed that perform the same function, regardless of structure). 
     Thus, for example, it will be appreciated by those of ordinary skill in the art that the diagrams, schematics, illustrations, and the like represent conceptual views or processes illustrating the exemplary embodiments. The functions of the various elements shown in the figures may be provided through the use of dedicated hardware as well as hardware capable of executing associated software. Similarly, any switches shown in the figures are conceptual only. Their function may be carried out through the operation of program logic, through dedicated logic, through the interaction of program control and dedicated logic, or even manually, the particular technique being selectable by the entity implementing this invention. Those of ordinary skill in the art further understand that the exemplary hardware, software, processes, methods, and/or operating systems described herein are for illustrative purposes and, thus, are not intended to be limited to any particular named manufacturer. 
     The exemplary embodiments describe a metering application. This metering application is a network management tool that dynamically adjusts bandwidth on a per-customer level. This metering application comprises methods, computer systems, and computer products that enforce a rate limit for data traffic. The metering application identifies a stream of data packets flowing though a server to a downstream end user. The metering application classifies the unidirectional stream according to a rate class, with each rate class having an associated rate limit. Each rate limit specifies a maximum bit rate at which the unidirectional stream may flow through the server. The end-user customer typically subscribes to a class of service. Each class of service has an associated maximum bit rate at which streams of data may flow downstream to the end-user customer. If the customer subscribes to a class of service having a high rate limit, the customer can receive/download data at high bit rates. If, however, the customer subscribes to a class of service having a low rate limit, the customer can only receive/download data at low bit rates. The metering application, then, polices and enforces the rate limit. When the customer requests a stream of data having an actual bit rate that exceeds the maximum bit rate permitted for the customer&#39;s rate class, the metering application decides whether the rate limit must be enforced. If the metering application enforces the rate limit, the metering application will discard packets of data to reduce the bit rate of the requested stream. 
       FIGS. 1-3  are schematics illustrating the exemplary embodiments. The embodiments include a metering application  20 . The metering application  20  comprises methods, systems, computer programs, and/or computer program products that police and enforce rate limits for streams of data. Streams of data travel or flow along a communications network at a bit rate. The bit rate is usually measured in bits per second, although other units are equally possible. To ensure that network bandwidth is efficiently utilized, the metering application  20  prevents some streams of data from exceeding a maximum bit rate. When a stream exceeds the maximum bit rate, the metering application  20  enforces the maximum bit rate. The metering application  20 , in simple terms, acts as a police officer. When a stream of data exceeds the maximum bit rate, or “speed limit,” the metering application  20  implements schemes that slow or reduce the bit rate. The following paragraphs will explain the various schemes. 
       FIG. 1  illustrates the metering application  20 . The metering application  20  operates within any computer system, such as a computer server  22 . The computer server  22  communicates with a downstream end-user device  24  via a communications network  26 . Although the end-user device  24  is generically shown, the end-user device  24  may be a computer system, a set-top box, an integrated set-top box and television, a modem, a cable modem, a digital subscriber line modem, or any other equipment, as will be described. The end-user device  24  could also be fiber optic equipment interfacing with the communications network  26 . The communications network  26  may be a cable network operating in the radio-frequency domain and/or the Internet Protocol (IP) domain. The communications network  26 , however, may also include a distributed computing network, such as the Internet (sometimes alternatively known as the “World Wide Web”), an intranet, a local-area network (LAN), and/or a wide-area network (WAN). The communications network  26  may include coaxial cables, copper wires, fiber optic lines, and/or hybrid-coaxial lines. The communications network  26  may even include wireless portions utilizing any portion of the electromagnetic spectrum and any signaling standard (such as the I.E.E.E. 802 family of standards, GSM/CDMA/TDMA or any cellular standard, and/or the ISM band). 
     As  FIG. 1  illustrates, a request  28  for content is received. The end-user desires to receive a movie, a television channel, music, or other content. The end-user then issues the request  28  for that content via the end-user device  24 . The request  28  communicates along the communications network  26  and eventually to a content server  30 . The content server  30  stores the content requested by the end-user. The content server  30  retrieves the requested content  32  and forwards that requested content to the end-user. 
       FIG. 2  illustrates a network tree structure  34 . As the requested content  32  communicates along the communications network  26  to the end-user device  24 , the requested content  32  encounters the metering application  20  operating in the computer server  22 . The computer server  22  receives the requested content  32 , and the metering application  20  identifies and classifies the requested content  32 . The computer server  22 , for example, may function as a router or a broadband remote access server (“BRAS”). Some network architectures utilize the computer server  22  as the last router in a downstream direction to the end-user device  24 . The requested content  32  may further flow through other layers of switches, computers, and/or devices, but the computer server  22  is the last intelligent device that classifies data traffic. 
       FIG. 3  is a schematic illustrating a scheme for enforcing rate limits, according to the exemplary embodiments. As the requested content  32  flows through the computer server  22 , the metering application  20  identifies any egressing, unidirectional stream  34  of Internet Protocol television data packets. That is, the metering application  20  identifies streams of Internet Protocol television data packets that are flowing out of the communications network  26  to the end-user device  24 . The stream  34  contains individual packets  36  of data, and each packet  36  contains Internet Protocol television information. The metering application  20  classifies the unidirectional stream  34  of Internet Protocol television data packets according to a rate class  38 , with each rate class having an associated rate limit  40 . Each rate limit  40  specifies a maximum bit rate at which the unidirectional stream  34  of Internet Protocol television data packets may flow. 
     The metering application  20  polices and enforces the rate limit  40 . If the actual bit rate of the unidirectional stream  34  exceeds the rate limit  40 , the metering application  20  decides whether to enforce the rate limit  40  (e.g., the “speed limit”). As  FIG. 3  shows, the metering application  20 , for example, may decide to discard packets of data within the unidirectional stream  34  of Internet Protocol television data packets. When packets are discarded, the bit rate is reduced. The metering application  20  may intentionally discard packets of data until the observed or measured bit rate is less than or equal to the maximum bit rate permitted for the associated rate class. The terms “discard,” “discarding,” “discarded,” and its variants mean packets of data are removed from the stream  34 . The terms “discard,” “discarding,” “discarded,” and its variants may also mean, as later explained, that information is removed or stripped from the stream  34 . The metering application  20 , then, may simply delete packets from the stream  34 . The discarded packets may be stored in a buffer memory  35  for later retrieval at a later time. When the metering application  20  discards packets, then a degraded stream  42  of Internet Protocol television data packets exits the computer server  22 . Because packets have been discarded, the degraded stream  42  has lesser bandwidth than the stream  34  entering the computer server  22 . How many packets that get discarded, and thus how much degradation is imposed, depends on the rate class  38  and the associated rate limit  40 . 
     The end-user may subscribe to a rate class. The end-user and a service provider may contract for a rate class. A service level agreement, for example, would define the service parameters. Typically various charges are established for different classes of service. The more the end-user pays, the higher the rate class and the corresponding rate limit. When the end-user&#39;s data requests exceed the rate limit for their rate class, then the metering application  20  degrades the end-user&#39;s content to maintain the rate limit. The metering application  20  meters on aggregate traffic rather than a single meter on a single pipe. The metering application  20  permits finer granularity that identifies traffic in particular classes and meters within that class. The metering application  20  then polices bit rates based on the rate limit  40  for classes of traffic. 
     The rate limit  40 , however, is also important for the service provider. In order to make the communications network  26  more manageable, and to make the selections of the ASPs and NSPs more manageable, bandwidth and Quality of Service (QoS) subsets will provided and the overall management of these capabilities will be governed by a policy-based system. This policy-based system permits customization down to the per-subscriber and application flow level. 
     The metering application  20  permits Bandwidth on Demand (BoD). Bandwidth on Demand is basically the ability to specify and to change the maximum rates for access. BoD may apply to Network Service Providers (NSP). The NSP&#39;s access to the communications network  26  can be set to receive various maximum bit rates. These changes affect their entire access session, and so all the applications within the session receive access to the new rate. The NSP could request this for a single subscriber, for all subscribers, or for a pre-defined tier of service. For example, all NSP access subscribers that have elected 256×128 Kb/s service might be provided a “free weekend” of 3 Mb×512 Kb/s in a promotion to entice them to upgrade their service. This weekend change in that service tier is an example of BoD. 
     ASP applications can be set to receive various maximum bit rates. Similar to the NSP service, but focused on a single application rather than the entire access session, BoD for ASP traffic would support setting both a universal speed limit to all customers as well as customer-specific speed limit for single customers. A “Turbo” feature, such as a Turbo button, is another term often used to describe the capability for both NSP accesses as well as ASP applications to change their maximum bit rates. 
     The rate class  38 , and the associated rate limit  40 , may not be a bandwidth guarantee. The rate limit  40  may be just that—a maximum for the service class. If BoD were offered in conjunction with a service class that guaranteed precedence over all other traffic, this precedence would constitute a bandwidth guarantee. Still, though, there is an expectation that the ASP or NSP gains something from the BoD service—even when it applies to best effort Internet. Also, there is an additional expectation that the NSP and ASP can query for a line rate maximum and can query for how much is already “committed” to other traffic. BoD may persist until it is specifically changed again—in other words, BoD may look like a provisioning function. Alternately, BoD may be requested for a specific interval, predefined interval, or until an access session is torn down. 
     The metering application  20  also permits Quality of Service (QoS). Because the metering application classifies streams of data, any number of classes is possible. The exemplary embodiments will describe three (3) distinct QoS treatment categories, although those of ordinary skill in the art will recognize that more, or less, classes are possible. 
     The lowest level class is “best effort.” That is, traffic in this class receives no treatment. This class is the typical “best effort” Internet service class. Most of the applications are assumed to be part of this class, and most applications will interact as they do today in an otherwise undifferentiated access arrangement. 
     Another class receives aggregate treatment. This class could includes most QoS applications. In this QoS arrangement, applications self-select from several shared priority levels. There are no bandwidth guarantees, and applications that select the same class may contend for that class&#39; resources. In this approach, applications need not “register” for a class a-priori. This class, therefore, must be able to account for QoS traffic so that it can be billed by bytes or buckets. Many levels are possible, and may include individual treatment. In this QoS arrangement, applications must register for a limited resource for a given time. These applications may have bandwidth expectations, and the approach is to cater to these expectation through prioritization. To prevent undesired interactions among applications at the same priority of service, it is required that per-application treatment, and possibly policing and/or queuing, will prevent contention among apps. In this resource reservation approach, resources are unavailable to similar applications whether the application is in use or not, so the proposed system must support billing both by timing resource allocation as well as by bytes or buckets over time periods—including by the minute. More specifically, applications that need special bandwidth assurance (like a required information rate) are allocated from bandwidth dedicated to this type of service from one of the top two tiers. 
     One such tier is a strict priority service or Expedited Forwarding. This traffic dominates all other traffic. It could be called a Platinum Olympic Class, and best current practice reserves this class for VoIP and control traffic. For this class to retain its integrity, applications are not allowed to self-select into the class. They must be admitted in a provisioning role and with limitations on the amount of bandwidth they are allowed to consume. Typically that bandwidth would be set to small fraction of the overall network capacity, and less than the total access line capacity so that other applications are not totally starved out. 
     Another such tier is higher priority service or Assured Forwarding. In this class, the traffic comes after the Expedited Forwarding tier, but before most other traffic. It could be called a Gold Olympic Class, and most applications that require some form of QoS might share one or more queues in this class. The key points are that the class of service can be shared, and queues dedicated to this level might police each application&#39;s capability to use the class. Policers, such as the metering application  20 , could allow committed rates, and mark bursts so that each app gets what it needs, and has a fair chance at bursting into uncommitted bandwidth. 
     Still another classification tier is standard priority service or Best Effort. In this class the traffic is part of the crowd. This class is expected to be shared by the overwhelming number of applications. In terms of fairness, applications get “whatever,” but can clearly grab bandwidth when competition is absent. And to be fair, “whatever” is typically understood and applied in predictable ways as is found on the Internet. This service class supports non QoS-enabled applications, and is basically what is done today almost everywhere for DSL. 
     Another tier is lower priority service or Lower Effort. This class is the background task or bulk mail service. Traffic assigned to this class is dominated by all other classes. While this seems like a completely undesirable and underserved approach to networking, it can provide cost-efficient value to certain applications. Notably peer-to-peer can be provided a “break” on bandwidth and download limits by self-selecting to “step out of the way” of more interactive applications, like e-mail and web surfing. Similarly, backup and subscription services that want to move a lot of data, but don&#39;t want to get in the way of more interactive uses of the DSL access can get their job done through this class. 
     So, how traffic is classified may determine the rate limit  40 . Once traffic is classified, the metering application  20  polices and enforces the rate limit  40 . When an actual bit rate exceeds the rate limit  40 , the metering application  20  decides whether to enforce the rate limit  40 . If the metering application  20  decides to enforce the rate limit  40 , the metering application may discard packets of data within the traffic. When packets are discarded, the bit rate is reduced. The metering application  20 , then, may include computer-readable instructions that logically specify when enforcement is required. The metering application  20 , for example, may strictly enforce the rate limit  40 . That is, when traffic exceeds the rate limit for the class, the metering application  20  has no discretion on enforcement. The metering application  20  discards packets until the actual bit rate is within the prescribed class limit. Alternatively, the metering application may actively decide to enforce the rate limit and may intentionally discard packets of data until the observed or measured bit rate is less than or equal to the maximum bit rate permitted for the associated rate class. Because packets are discarded, the metering application  20  produces a degraded version of traffic. The degraded version has a lesser bandwidth and, thus, a lower bit rate. 
     A sophisticated scheme, however, includes discretion. The metering application  20  may utilize multiple sources of information to decide when enforcement of the rate limit  40  is needed. Even though a particular end-user is requesting content that exceeds the rate limit  40 , the metering application may have discretion to enforce. The metering application  20 , for example, may weigh current network bandwidth requirements. The communications network  26 , for example, might have excess bandwidth availability, so the metering application  20  may permit the end-user to exceed the rate limit  40 . If the customer&#39;s request would degrade network performance below some threshold, then the metering application may also have discretion to degrade the customer&#39;s service to maintain adequate network performance levels. 
     Another discretionary scheme may include business models. Various business issues may also influence when, and how, the metering application  20  enforces the rate limit  40 . The end-user&#39;s monthly payment, and/or payment history, for example, may determine how rate requests are handled. Perhaps the end-user is a “good” customer, so the metering application  20  “overlooks” excessive bit rates. What determines a “good” customer, of course, may have many meanings. The end-user may have a consistent and on-time payment history, so the metering application  20  has discretion to enforce the rate limit  40 . If the end-user has a history of one or more delinquent payments, however, the metering application  20  may more strictly enforce rate limits. Delinquent payments may, then, influence the frequency of enforcement of the rate limit  40 . Service level agreements may be enforced more strictly, or more leniently, based upon payment history. 
     Other business models may include customer abuse of the communications network  26 . The end-user may have a history of “bad behavior,” and this behavior may influence how and/or when packets of data are discarded. If, for example, the end-user is a sender of spam email or other spam content, the service provider may decide to strictly enforce rate limits. Other undesirable or “bad” behavior may include suspected infringement of intellectual property rights, such as downloading of copyrighted content. Even objectionable content requests, such as pornographic content requests, may be degraded to a lower rate limit. In fact, some classes of content, or even the content itself, may default to lower rate limits to discourage requests and downloads. Rate limits could be imposed based upon the requested content. Content having little or no risk may have a higher rate limit than riskier content. 
     Another discretionary scheme may include a history of excessive bit rate requests. The metering application  20  may track the frequency of customer requests that exceed their rate limit. The metering application  20  may have discretion to ignore, or only slightly degrade, infrequent requests that exceed the rate limit  40 . In other words, if the end-user rarely exceeds the rate limit  40  for their class, the metering application  20  has discretion. If, however, the end-user frequently requests or sends traffic that exceeds the rate limit  40 , this persistent activity may influence metering and/or discarding of packets. 
     The various discretionary schemes may be contained within a profile. However the metering application  20  decides to degrade service, the metering application may consult a profile. Each end-user would have a profile, and the profile is stored in a database. When the metering application  20  detects an excessive bit rate, the metering application  20  queries the customer&#39;s profile stored in the database. The customer&#39;s profile contains payment history and/or usage history. The metering application would retrieve information from the profile to determine whether degradation is desired. 
       FIG. 4  is a schematic illustrating another scheme for enforcing rate limits, according to more exemplary embodiments. When actual bit rates exceed the rate limit  40 , the metering application  20  may degrade traffic to reduce the bit rate.  FIG. 4  illustrates the requested content  32  flowing to the computer server  22 . The metering application  20  identifies the requested content  32  as a high-definition stream  50  of Internet Protocol television data packets. The metering application  20  then classifies the high-definition stream  50  according to the rate class  38  and the associated rate limit  40 . If, however, the actual bit rate of the high-definition stream  50  exceeds the rate limit  40 , the metering application  20  must decide whether to enforce the rate limit  40 . If the metering application  20  decides to enforce the rate limit, the metering application  20  may decide to degrade the high-definition stream  50  of Internet Protocol television data packets.  FIG. 4 , then, illustrates that the metering application may degrade the high-definition stream  50  to a standard definition stream  52  of Internet Protocol television data packets. That is, the metering application  20  discards packets of data, such that the high-definition content is lost. What emerges from the computer server  22  is the degraded, standard definition stream  52  of Internet Protocol television data packets. The metering application  20  thus causes degradation from high definition television service to standard definition television service. The bit rate of the degraded, standard definition stream  52  is less than or equal to the rate limit  40 . 
       FIGS. 5-7  are schematics illustrating another scheme for enforcing rate limits, according to yet more exemplary embodiments. Here the end-user, using the end-user device  24 , makes two requests for content streams. One or both content streams exceed the allowable rate limit for the class, so the metering application  20  must decide whether this excessive rate request is permissible. When the metering application  20  enforces the rate limit  40 , the metering application  20  must apply a scheme for concurrent streams. 
       FIG. 5 , then, illustrates one scheme for concurrent streams. As  FIG. 5  shows, the end-user issues the first request  28  for content and, and some other time, the end-user issues a subsequent, second request  56  for content. The first request  28  communicates to the content server  30 , and the content server  30  retrieves and forwards the requested first content  32 . Similarly, the subsequent request  56  communicates to another content server  58  (or the content server  30 ), and that another content server  58  retrieves and forwards the subsequently requested content  60 . Both streams  32 ,  60  communicate along the communications network  26  and encounter the metering application  20  operating in the computer server  22 . The metering application  20  identifies and classifies each stream  32  and  60 . Because both streams  32  and  60  are destined for the same end-user device  24 , most likely a single rate limit  40  applies to the combined bandwidth. That is, even though the end-user has requested two distinct streams of data, the bandwidth consumed by both streams still must be less than or equal to the rate limit  40 . When the rate limit  40  is exceeded, the metering application  20  must decide whether degradation is needed and, if so, how one or both streams are degraded. 
     When degradation is needed, the metering application may employ various schemes. As  FIG. 5  illustrates, one simple scheme is to cancel, or drop, one of the requested streams. The metering application  20  decides which stream  32  or  60  is dropped.  FIG. 5  applies the “first in, first out” principle such that the requested first content  32  is permitted to pass to the end-user device  24 . The metering application  20 , however, decides to drop or cancel the subsequently requested content  60 . If the bit rate of the remaining first content stream  32  is less than the rate limit  40 , then no further processing may be required. If, however, the bit rate of the remaining first content stream  32  is still greater than the rate limit  40 , then the metering application  20  would apply the other schemes discussed herein to further reduce the bit rate. Even though  FIG. 5  illustrates the “first in, first out” principle, the metering application  20  could alternatively employ a “last in, first out” principle. 
       FIG. 6  is a schematic illustrating an alternative scheme for concurrent streams, according to the exemplary embodiments.  FIG. 6  is similar to  FIG. 5  and again shows both streams  32  and  60  communicating along the communications network  26  and encountering the metering application  20  operating in the computer server  22 . Because both streams  32  and  60  are destined for the same end-user device  24 , the bandwidth consumed by both streams must be less than or equal to the rate limit  40 . When the rate limit  40  is exceeded, here the metering application  20  degrades both streams  32  and  60 . That is, the metering application  20  discards packets of data from both the first stream  32  and the subsequent second stream  60  to reduce the combined bit rate. Here, then, the metering application  20  strives to provide both streams to the same end-user, but both streams  32  and  60  must be degraded. The metering application  20 , for example, could degrade high-definition television service to standard definition service. Should both the first stream  32  and the second stream  60  be composed of high-definition Internet Protocol television data packets, the metering application  20  would discard packets from both streams such that the combined bit rate is less than or equal to the maximum bit rate. The metering application  20  would discard packets of data such that both streams  32  and  60  are reduced to standard-definition Internet Protocol television service. The degraded, standard-definition Internet Protocol television service streams  62  and  64  are delivered to end user device  24 . 
       FIG. 7  is a schematic illustrating another scheme for concurrent streams, according to the exemplary embodiments. The end-user, as before, issues the first request  28  for content and the subsequent request  56  for content. The metering application  20  receives notification of each request  28  and  56 . The metering application  20  is informed of each request  28  and  56  by various means. Each request  28  and  56 , for example, may first route to the metering application  20 . Each content server  30  and  58 , alternatively or additionally, may communicate a notification of each requested stream to the metering application  20 . A network control layer may also inform the metering application  20  of each request  28  and  56 . Regardless of how the metering application  20  is informed, the metering application  20  may determine that the combined bandwidth consumed by both streams will exceed the rate limit  40 . Here, then, the metering application  20  proactively cancels the subsequent request  56  for content. The metering application  20  may communicate a cancel command to the second content server  58 . The metering application  20  may additionally or alternatively quarantine the subsequent request  56  for content, thus preventing the second content server  58  from receiving the subsequent request  56 . If the bit rate of the first requested content stream  32  is less than the rate limit  40 , then no further processing may be required. If, however, the bit rate of the remaining first content stream  32  is still greater than the rate limit  40 , then the metering application  20  would apply the schemes discussed herein to further reduce the bit rate. 
       FIG. 8  is a schematic illustrating another scheme for enforcing rate limits, according to more exemplary embodiments. Here the metering application  20  strips and discards certain information to reduce bandwidth. The requested content  32  flows to the computer server  22 . The metering application  20  identifies the requested content  32  as a stream  70  of Internet Protocol television data packets. The metering application  20  then classifies the stream  70  according to the rate class  38  and the associated rate limit  40 . When the actual bit rate of the stream  70  exceeds the rate limit  40 , the metering application  20  must decide whether to enforce the rate limit  40 . If the metering application  20  enforces the rate limit  40 , the metering application  20  may remove or strip information from the stream  70  of Internet Protocol television data packets.  FIG. 8 , for example, illustrates that the metering application  20  strip and discard color information from the stream  70  of Internet Protocol television data packets to reduce the bit rate. The resultant, egressing stream  72  exiting the computer server  22  would be reduced in bandwidth to essentially a black and white television experience. If the bit rate of the stream  70  still exceeds the rate limit  40 , the metering application  20  may additionally or alternatively strip and discard audio information from the stream  70  of Internet Protocol television data packets to reduce the bit rate. 
       FIG. 9  is a schematic illustrating more schemes for enforcing rate limits, according to still more exemplary embodiments. Here the metering application  20  uses multi-layer encoding to reduce bandwidth. The metering application  20  receives multiple layers of coded streams corresponding to different sized pictures. The metering application  20 , for example, may receive a coded one-quarter (¼) stream  74  and a coded one-half (½) stream  76 . The coded one-quarter (¼) stream  74  requires one fourth (¼) of the bandwidth of a full-sized stream, while the coded one-half (½) stream  76  requires one half (½) of the bandwidth of a full-sized stream. The coded one-quarter (¼) stream  74  contains one fourth the pixels, thus producing only a quarter screen experience at the end-user&#39;s display device. Similarly, the coded one-half (½) stream  76  contains fifty percent (50%) of the pixels, thus producing a half-screen experience at the end-user&#39;s display device. The metering application may sum, or replicate, various streams to achieve whatever picture scale or size is desired. When the metering application  20  must degrade a stream to enforce the rate limit  40 , the metering application  20  can selectively differentiate between the coded streams  74  and  76  to reduce bandwidth. The end-user receives their requested content, but the viewing experience (e.g., screen size) is degraded, and thus bandwidth is reduced, according to the rate limit  40 . 
       FIG. 10  is a schematic illustrating yet more schemes for enforcing rate limits, according to even more exemplary embodiments. Here the metering application  20  receives two separate channels streams. A standard definition stream  78  is encoded at a standard definition rate, while a high-definition stream  80  is encoded at a high definition rate. If the rate class  38  permits the higher rate of the high definition stream  80 , then no degradation is needed. If, however, the rate class  38  does not permit transmission of the high definition stream  80 , the metering application  20  switches feeds to the standard definition stream  78 . So, even though the end-user may have requested an HDTV experience, the end-user only subscribes to a standard definition class. 
       FIG. 11  is a schematic illustrating more schemes for enforcing rate limits, according to more exemplary embodiments. Here the metering application  20  again receives two separate channels streams. The standard definition stream  78  is encoded at the standard definition rate. A delta definition stream  82  is also received, and the delta definition stream  82  contains additional information for the HDTV experience. If the rate class  38  permits the HDTV experience, then the metering application  20  passes, or sums, the standard definition stream  78  and the delta definition stream  82 . If, however, the rate class  38  does not permit an HDTV experience, the metering application  20  only communicates the standard definition stream  78 . Again, even though the end-user may have requested an HDTV experience, if the end-user only subscribes to a standard definition class, the metering application  20  degrades to the standard TV experience. 
     The end-user device  24  may also take actions. When the metering application  20  discards packets, the end-user device  24  may intelligently determine that poor video conditions exist. Recall that when the metering application  20  discards packets, the degraded stream (shown as reference numeral  42  in  FIG. 3 ) exits the computer server  22 . Because packets have been discarded, the degraded stream has a lesser bandwidth. The degraded stream travels along the communications network  26  to the end-user device  24 . When the end-user device  24  receives the degraded stream, the end-user device may itself analyze the degraded stream. The end-user device  24  may determine that too much information has been discarded. That is, the degraded stream produces an unacceptable video experience. The end-user device  24  may then determine that the requested, but degraded, channel is unavailable. 
     Data streams may also be enhanced. Heretofore the metering application  20  has been described as discarding/clipping packets to reduce bandwidth. The metering application  20 , however, may also enhance streams of data. The metering application  20 , for example, may enhance data to improve color, sound, resolution, or any other characteristic or performance criteria. The end-user device  24 , likewise, may also enhance streams. Recall again that the metering application  20  discards or clips packets to reduce bandwidth. When the end-user device  24  receives the degraded stream, the end-user device analyzes the degraded stream. If the amount of clipping is small/limited, the end-user device may take actions to enhance picture quality. The end-user device may interpolate between data, and/or the end-user device  24  may correct for noticeable and/or known errors or conditions. 
     The metering application  20  operates regardless of the packet protocol. That is, any packet protocol is suitable for these concepts. As those of ordinary skill in the art understand, sometimes information is packetized (or “framed”) for use in packet networks. The information is grouped into packets according to a packet protocol. As those of ordinary skill in the art also understand, there are many packet protocols. Some of the more well-known packet protocols include TCP/IP, IPX/SPX, AppleTalk, and SNA. Some standards organizations, such as the I.E.E.E., issue standards for packetizing data. Because many networks are “mixed”—that is, the network receives and handles packets of differing protocols, a “translator” determines the particular packet protocol and the appropriate destination for each packet. Because the basics of packetizing and packet protocols are well-known, packetizing schemes are not further described here. 
       FIG. 12  depicts another possible operating environment for the exemplary embodiments.  FIG. 12  is a block diagram showing the metering application  20  residing in a computer system  130  (such as the computer server  22  shown in  FIGS. 1-11 ).  FIG. 12 , however, may also represent a block diagram of the end-user device (shown as reference numeral  24  in  FIGS. 1-11 ).  FIG. 12 , in fact, may represent a block diagram of the metering application  20  operating in any processor-controlled device, such as a personal digital assistant (PDA), a Global Positioning System (GPS) device, an interactive television, an Internet Protocol (IP) phone, a pager, a cellular/satellite phone, or any communications device utilizing a digital signal processor (DSP).  FIG. 12  may also represent a block diagram of watches, radios, vehicle electronics, clocks, printers, gateways, and other apparatuses and systems utilizing the metering application  20 . 
     As  FIG. 12  shows, the metering application  20  operates within a system memory device. The metering application  20 , for example, is shown residing in a memory subsystem  132 . The metering application  20 , however, could also reside in flash memory  134  or peripheral storage device  136 . The computer system  130  also has one or more central processors  138  executing an operating system. The operating system, as is well known, has a set of instructions that control the internal functions of the computer system  130 . A system bus  140  communicates signals, such as data signals, control signals, and address signals, between the central processor  138  and a system controller  142  (typically called a “Northbridge”). The system controller  142  provides a bridging function between the one or more central processors  138 , a graphics subsystem  144 , the memory subsystem  132 , and a PCI (Peripheral Controller Interface) bus  146 . The PCI bus  146  is controlled by a Peripheral Bus Controller  148 . The Peripheral Bus Controller  148  (typically called a “Southbridge”) is an integrated circuit that serves as an input/output hub for various peripheral ports. These peripheral ports could include, for example, a keyboard port  150 , a mouse port  152 , a serial port  154  and/or a parallel port  156  for a video display unit, one or more external device ports  158 , and networking ports  160  (such as SCSI or Ethernet). The Peripheral Bus Controller  148  could also include an audio subsystem  162 . Those of ordinary skill in the art understand that the program, processes, methods, and systems described herein are not limited to any particular computer system or computer hardware. 
     One example of the central processor  138  may be a microprocessor. Advanced Micro Devices, Inc., for example, manufactures a full line of ATHLON™ microprocessors (ATHLON™ is a trademark of Advanced Micro Devices, Inc., One AMD Place, P.O. Box 3453, Sunnyvale, Calif. 94088-3453, 408.732.2400, 800.538.8450). The Intel Corporation also manufactures a family of X86 and P86 microprocessors (Intel Corporation, 2200 Mission College Blvd., Santa Clara, Calif. 95052-8119, 408.765.8080). Other manufacturers also offer microprocessors. Such other manufacturers include Motorola, Inc. (1303 East Algonquin Road, P.O. Box A3309 Schaumburg, Ill. 60196), International Business Machines Corp. (New Orchard Road, Armonk, N.Y. 10504, (914) 499-1900), and Transmeta Corp. (3940 Freedom Circle, Santa Clara, Calif. 95054). Those skilled in the art further understand that the program, processes, methods, and systems described herein are not limited to any particular manufacturer&#39;s central processor. 
     According to an exemplary embodiment, the WINDOWS® (WINDOWS® is a registered trademark of Microsoft Corporation, One Microsoft Way, Redmond Wash. 98052-6399, 425.882.8080) operating system may be used. Other operating systems, however, are also suitable. Such other operating systems would include the UNIX® operating system (UNIX® is a registered trademark of the Open Source Group), the UNIX-based Linux operating system, WINDOWS NT®, and Mac® OS (Mac® is a registered trademark of Apple Computer, Inc., 1 Infinite Loop, Cupertino, Calif. 95014, 408.996.1010). Those of ordinary skill in the art again understand that the program, processes, methods, and systems described herein are not limited to any particular operating system. 
     The system memory device (shown as memory subsystem  132 , flash memory  134 , or peripheral storage device  136 ) may also contain an application program. The application program cooperates with the operating system and with a video display unit (via the serial port  154  and/or the parallel port  156 ) to provide a Graphical User Interface (GUI). The Graphical User Interface typically includes a combination of signals communicated along the keyboard port  150  and the mouse port  152 . The Graphical User Interface provides a convenient visual and/or audible interface with a user of the computer system  130 . 
       FIG. 13  is a flowchart illustrating a method of enforcing a rate limit for data traffic. A unidirectional stream is identified flowing though a server to a downstream end user (Block  170 ). The unidirectional stream is classified according to a rate class (Block  172 ). Each rate class has an associated rate limit, and each rate limit specifies a maximum bit rate at which the unidirectional stream may flow (Block  174 ). The unidirectional stream may be classified according to at least one of i) the end user&#39;s monthly payment history (Block  176 ), ii) the end user&#39;s abuse of network privileges (Block  178 ), and/or iii) the end user&#39;s history of excessive bit rate requests (Block  180 ). Enforcement of the rate limit may be influenced by a history of one or more delinquent payments, a history of bad behavior (such as spamming activity), and/or a history of repeated requests for data that exceed the maximum bit rate. If the actual bit rate is less than or equal to the rate limit (Block  182 ), then the metering application need not, but still may, take action to reduce bandwidth. If, however, the actual bit rate exceeds the rate limit (Block  182 ), then packets of data are discarded to reduce bit rates (Block  184 ). 
     The flowchart continues with  FIG. 14 . Packets are discarded until the bit rate is less than or equal to the maximum bit rate permitted for the associated rate class (Block  186 ). The discarded packets may cause degradation from high definition television service to standard definition television service (Block  188 ). Color information may be stripped to reduce the bit rate (Block  190 ). Audio information may also be stripped from the unidirectional stream to reduce bit rate (Block  192 ). If a request for a second unidirectional stream is received from the same end user (Block  194 ), then that request is processed (Block  196 ). If, however, the combined bit rate of the first and second streams exceeds the maximum bit rate permitted for the associated rate class (Block  198 ), then the subsequent request may be canceled (Block  200 ). An alternative scheme discards packets of data from both the first and second streams to reduce the combined bit rate such that the combined bit rate is less than or equal to the maximum bit rate (Block  202 ). 
     The metering application may be physically embodied on or in a computer-readable medium. This computer-readable medium may include CD-ROM, DVD, tape, cassette, floppy disk, memory card, and large-capacity disk (such as IOMEGA®, ZIP®, JAZZ®, and other large-capacity memory products (IOMEGA®, ZIP®, and JAZZ® are registered trademarks of Iomega Corporation, 1821 W. Iomega Way, Roy, Utah 84067, 801.332.1000). This computer-readable medium, or media, could be distributed to end-users, licensees, and assignees. These types of computer-readable media, and other types not mention here but considered within the scope of the exemplary embodiments, allow the metering application to be easily disseminated. A computer program product comprises the metering application stored on the computer-readable medium. The metering application comprises computer-readable instructions for enforcing a rate limit for data traffic. The computer-readable instructions identify a unidirectional stream flowing though a server to a downstream end user. The unidirectional stream is classified according to a rate class, with each rate class having an associated rate limit. Each rate limit specifies a maximum bit rate at which the unidirectional stream may flow. Packets of data within the unidirectional stream are discarded to reduce a bit rate such that the bit rate is less than or equal to the maximum bit rate permitted for the associated rate class. 
     The metering application may be physically embodied on or in any addressable (e.g., HTTP, I.E.E.E. 802.11, Wireless Application Protocol (WAP)) wireless device capable of presenting an IP address. Examples could include a computer, a wireless personal digital assistant (PDA), an Internet Protocol mobile phone, or a wireless pager. 
     While the exemplary embodiments have been described with respect to various features, aspects, and embodiments, those skilled and unskilled in the art will recognize the exemplary embodiments are not so limited. Other variations, modifications, and alternative embodiments may be made without departing from the spirit and scope of the exemplary embodiments.