Abstract:
A method includes receiving a web content request including a URL string for locating the web content, and comparing the URL string to a list of URLs for which prefetched responses are available to see if the request can be fulfilled from these responses. The method further includes using a mask that excludes portions of the URL string that are not relevant to finding or selecting the web content when comparing the request to the list of prefetched URLs. If the request URL string matches the URL of a prefetched response other than the masked section, then the prefetched response can be supplied as a response to the incoming response. The method further includes parsing Java scripts in a web response to search for URLs that may be rendered on a web page and analyzing the scripts to identify bytes in the URL that would have random values.

Description:
PRIORITY CLAIM 
       [0001]    This application is a non-provisional application which claims priority to U.S. Provisional Application No. 61/143,933, entitled WEB OPTIMIZATION OVER SATELLITE LINKS, filed on Jan. 12, 2009, which is incorporated by reference in its entirety for any and all purposes. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates, in general, to network acceleration, and more particularly, to URL masking in prefetched and cached systems. 
       BACKGROUND OF THE INVENTION 
       [0003]    Presently, cold access (first visit on clear cache) to popular sites is a well-established metric for user experience on a public network, as it is the operation in which network performance is most clearly and frequently apparent to the end user. Consequently, improvements in this metric can play a significant role in driving consumer purchasing decisions, such as in selecting network access providers or deciding whether to use an acceleration service. 
         [0004]    Performance for satellite access to commercial web sites can be significantly improved. Currently, an effective solution for many of the issues affecting satellite performance exist. For example, optimal transport protocols and compression are effective at reducing the number of bytes downloaded. However, another aspect of network acceleration involves the number of RTTs. At present, about 66% of the objects for cold access to public sites are prefetched, and many of the non-prefetched requests occur sequentially because URL references within Java scripts have to be resolved before subsequent HTML data can be parsed. Over a broadband satellite link, these accumulated RTTs are the largest contributor to download times. 
         [0005]    Furthermore, delays in receiving content from upstream servers is another problem that broadband satellite links face. Even if all references could be prefetched from the initial request, the web page may be delayed while waiting for responses from the origin servers. Improvements in these two areas could potentially make a satellite link comparable to terrestrial broadband for accessing public web sites. The fastest fiber links must still wait for a series of requests to be satisfied from remote web hosts, so that the total download time is the accumulation of these web server response delays. Hence, improvements in the art are needed. 
       BRIEF SUMMARY OF THE INVENTION 
       [0006]    Embodiments of the present invention relate to a method for implementing URL masking. The method includes receiving a web content request including a URL string for locating the web content, and comparing the URL string to a list of URLs for which prefetched responses are available to see if the request can be fulfilled from these responses. The method further includes using a mask that excludes portions of the URL string that are not relevant to finding or selecting the web content when comparing the request to the list of prefetched URLs. If the request URL string matches the URL of a prefetched response other than the masked section, then the prefetched response can be supplied as a response to the incoming response. The method further includes parsing Java scripts in a web response to search for URLs that may be rendered on a web page and analyzing the scripts to identify bytes in the URL that would have random values. A mask is then generated that indicates which bytes are random and can be excluded from the comparison that determines whether a prefetched response can be used. 
         [0007]    Another embodiment of the present invention includes a gateway configured to implement URL masking. The gateway includes an accelerator module configured to receive a web content response containing HTML or other file types containing Java script and parse the Java script to identify URLs that the client application such as a web browser can be expected to request in rendering the web page. The accelerator module analyzes the Java scripts to determine whether a function that produces random data is being used to generate part of the URL. If so, the random bytes in the URL are identified in a mask. The gateway further includes a gateway transceiver module in communication with the accelerator module. The gateway transceiver module is configured to receive the prefetched object and transmit the prefetched object to a terminal. 
         [0008]    A further embodiment of the present invention provides a machine-readable medium for implementing URL masking. The machine-readable medium includes instructions for receiving a web content request including a URL string for locating the web content, and comparing the URL string to a list of URLs for which prefetched responses are available to see if the request can be fulfilled from these responses. The machine-readable medium further includes instructions for using a mask that excludes portions of the URL string that are not relevant to finding or selecting the web content when comparing the request to the list of prefetched URLs. If the request URL string matches the URL of a prefetched response other than the masked section, then the prefetched response can be supplied as a response to the incoming response. The machine-readable medium further includes instructions for parsing Java scripts in a web response to search for URLs that may be rendered on a web page and analyzing the scripts to identify bytes in the URL that would have random values. A mask is then generated that indicates which bytes are random and can be excluded from the comparison that determines whether a prefetched response can be used. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A further understanding of the nature and advantages of the present invention may be realized by reference to the remaining portions of the specification and the drawings wherein like reference numerals are used throughout the several drawings to refer to similar components. In some instances, a sublabel is associated with a reference numeral to denote one of multiple similar components. When reference is made to a reference numeral without specification to an existing sublabel, it is intended to refer to all such multiple similar components. 
           [0010]      FIG. 1  is a block diagram illustrating satellite communications, according to one embodiment of the present invention. 
           [0011]      FIG. 2  is a block diagram illustrating a gateway, according to one embodiment of the present invention. 
           [0012]      FIG. 3  is a block diagram illustrating a subscriber terminal, according to one embodiment of the present invention. 
           [0013]      FIG. 4  is a generalized schematic diagram illustrating a computer system, in accordance with various embodiments of the invention. 
           [0014]      FIG. 5  is a block diagram illustrating a networked system of computers, which can be used in accordance with various embodiments of the invention. 
           [0015]      FIG. 6  is a block diagram illustrating a system for implementing prefetching, according to one embodiment of the present invention. 
           [0016]      FIGS. 7A and 7B  are block diagrams illustrating a network acceleration module, according to one embodiment of the present invention. 
           [0017]      FIG. 8  is a flow diagram illustrating a method for implementing URL masking, according to one embodiment of the present invention. 
           [0018]      FIG. 9  is a flow diagram illustrating a method for further implementing URL masking, according to one embodiment of the present invention. 
           [0019]      FIG. 10  is a block diagram illustrating a system for implementing URL masking, according to one embodiment of the present invention. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    The ensuing description provides exemplary embodiment(s) only, and is not intended to limit the scope, applicability or configuration of the disclosure. Rather, the ensuing description of the exemplary embodiment(s) will provide those skilled in the art with an enabling description for implementing an exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements without departing from the spirit and scope as set forth in the appended claims. Some of the various exemplary embodiments may be summarized as follows. 
         [0021]    According to some embodiments, a URL masking algorithm is provided to allow prefetchers and caches to work even when the URLs are constructed using scripts intended to block such behavior. For example, certain cache-busting techniques generate portions of the URL string, using Java scripts, to include unique values (e.g., random numbers, timestamps, etc.). As such, prefetchers may be fooled into thinking objects at the URL have not yet been prefetched, when in fact they have. Embodiments mask these cache-busting portions of the URL string to allow the prefetcher to recognize the request as a previously prefetched URL. 
         [0022]    According to other embodiments, cache cycling is used to issue a fresh request to the content provider for website content each time the proxy server serves a request from cached data. For example, URL masking may allow a prefetcher to operate in the context of a cache-busting algorithm. Using prefetched content may reduce the apparent number of times the URL is requested, which may reduce advertising revenue and other metrics based on the number of requests. Cache cycling embodiments maintain the request metrics while allowing optimal prefetching in the face of cache-busting techniques. 
         [0023]    According to other embodiments, a number of techniques are provided for optimizing prefetcher functionality. In one embodiment, an accumulator is provided for optimizing performance of an accelerator abort system. Chunked content (e.g., in HTTP chunked mode) is accumulated until enough data is available to make an abort decision. In another embodiment, socket mapping architectures are adjusted to allow prefetching of content copies for URLs requested multiple times on the same page. In yet another embodiment, persistent storage is adapted to cache prefetched, but unused data, and to provide access to the data to avoid subsequent redundant prefetching. In still another embodiment, DNS transparent proxy and prefetch are integrated with HTTP transparent proxy and prefetch, so as to piggyback DNS information with HTTP frames. In even another embodiment, prefetching is provided for the DNS associated with all hostnames called in java scripts to reduce the number of requests needed to the DNS server. And in another embodiment, delivery of objects is prioritized according to browser rendering characteristics. For example, data is serialized back to a subscriber&#39;s browser so as to prioritize objects needing further parsing or having valuable information with respect to rendering. 
         [0024]    It will be appreciated that these and other embodiments will be described in more detail below and with respect to the appended figures. In the appended figures, similar components and/or features may have the same reference label. Further, various components of the same type may be distinguished by following the reference label by a dash and a second label that distinguishes among the similar components. If only the first reference label is used in the specification, the description is applicable to any one the similar components having the same first reference label irrespective of the second reference label. 
         [0025]    Referring first to  FIG. 1 , a block diagram is shown of one embodiment of a satellite communications system  100 . The satellite communications system  100  includes a network  120 , such as the Internet, interfaced with a gateway  115  that is configured to communicate with one or more subscriber terminals  130 , via a satellite  105 . A gateway  115  is sometimes referred to as a hub or ground station. Subscriber terminals  130  are sometimes called modems, satellite modems, or user terminals. As noted above, although the communications system  100  is illustrated as a geostationary satellite  105  based communication system, it should be noted that various embodiments described herein are not limited to use in geostationary satellite based systems; for example, some embodiments could be low earth orbit (“LEO”) satellite based systems or aerial payloads not in orbit and held aloft by planes, blimps, weather balloons, etc. Other embodiments could have a number of satellites instead of just one. 
         [0026]    The network  120  may be any type of network and can include, for example, the Internet, an Internet protocol (“IP”) network, an intranet, a wide-area network (“WAN”), a local-area network (“LAN”), a virtual private network (“VPN”), the Public Switched Telephone Network (“PSTN”), and/or any other type of network supporting data communication between devices described herein, in different embodiments. A network  120  may include both wired and wireless connections, including optical links. As illustrated in a number of embodiments, the network  120  may connect the gateway  115  with other gateways (not shown), which are also in communication with the satellite  105 . 
         [0027]    The gateway  115  provides an interface between the network  120  and the satellite  105 . The gateway  115  may be configured to receive data and information directed to one or more subscriber terminals  130 , and can format the data and information for delivery to the respective destination device via the satellite  105 . Similarly, the gateway  115  may be configured to receive signals from the satellite  105  (e.g., from one or more subscriber terminals  130 ) directed to a destination in the network  120 , and can process the received signals for transmission along the network  120 . 
         [0028]    A device (not shown) connected to the network  120  may communicate with one or more subscriber terminals  130 . Data and information, for example IP datagrams, may be sent from a device in the network  120  to the gateway  115 . It will be appreciated that the network  120  may be in further communication with a number of different types of providers, including content providers, application providers, service providers, etc. Further, in various embodiments, the providers may communicate content with the satellite communication system  100  through the network  120 , or through other components of the system (e.g., directly through the gateway  115 ). 
         [0029]    The gateway  115  may format frames in accordance with a physical layer definition for transmission to the satellite  105 . A variety of physical layer transmission modulation and coding techniques may be used with certain embodiments, including those defined with the DVB-S2 standard. The link  135  from the gateway  115  to the satellite  105  may be referred to hereinafter as the downstream uplink  135 . The gateway  115  uses the antenna  110  to transmit the content to the satellite  105 . In one embodiment, the antenna  110  comprises a parabolic reflector with high directivity in the direction of the satellite and low directivity in other directions. 
         [0030]    In one embodiment, a geostationary satellite  105  is configured to receive the signals from the location of antenna  110  and within the frequency band and specific polarization transmitted. The satellite  105  may, for example, use a reflector antenna, lens antenna, array antenna, active antenna, or other mechanism for reception of such signals. The satellite  105  may process the signals received from the gateway  115  and forward the signal from the gateway  115  containing the MAC frame to one or more subscriber terminals  130 . In one embodiment, the satellite  105  operates in a multi-beam mode, transmitting a number of narrow beams each directed at a different region of the earth. 
         [0031]    With such a multibeam satellite  105 , there may be any number of different signal switching configurations on the satellite  105 , allowing signals from a single gateway  115  to be switched between different spot beams. In one embodiment, the satellite  105  may be configured as a “bent pipe” satellite, wherein the satellite may frequency convert the received carrier signals before retransmitting these signals to their destination, but otherwise perform little or no other processing on the contents of the signals. There could be a single carrier signal for each service spot beam or multiple carriers in different embodiments. Similarly, single or multiple carrier signals could be used for the feeder spot beams. A variety of physical layer transmission modulation and coding techniques may be used by the satellite  105  in accordance with certain embodiments, including those defined with the DVB-S2 standard. For other embodiments, a number of configurations are possible (e.g., using LEO satellites, or using a mesh network instead of a star network). 
         [0032]    The service signals transmitted from the satellite  105  may be received by one or more subscriber terminals  130 , via the respective subscriber antenna  125 . In one embodiment, the subscriber antenna  125  and terminal  130  together comprise a very small aperture terminal (“VSAT”), with the antenna  125  measuring approximately 0.6 meters in diameter and having approximately 2 watts of power. In other embodiments, a variety of other types of subscriber antennae  125  may be used at the subscriber terminal  130  to receive the signal from the satellite  105 . The link  150  from the satellite  105  to the subscriber terminals  130  may be referred to hereinafter as the downstream downlink  150 . Each of the subscriber terminals  130  may include a hub or router (not pictured) that is coupled to multiple subscriber terminals  130 . 
         [0033]    In some embodiments, some or all of the subscriber terminals  130  are connected to consumer premises equipment (“CPE”)  160 . CPE may include, for example, computers, local area networks, Internet appliances, wireless networks, etc. A subscriber terminal  130 , for example  130 - a , may transmit data and information to a network  120  destination via the satellite  105 . The subscriber terminal  130  transmits the signals via the upstream uplink  145 - a  to the satellite  105  using the subscriber antenna  125 - a . The link from the satellite  105  to the gateway  115  may be referred to hereinafter as the upstream downlink  140 . 
         [0034]    In various embodiments, one or more of the satellite links  135 ,  140 ,  145 ,  150  are capable of communicating using one or more communication schemes. In various embodiments, the communication schemes may be the same or different for different links. The communication schemes may include different types of coding and modulation combinations. For example, various satellite links may communicate using physical layer transmission modulation and coding techniques using adaptive coding and modulation schemes, etc. The communication schemes may also use one or more different types of multiplexing schemes, including Multi-Frequency Time-Division Multiple Access (“MF-TDMA”), Time Division Multiple Access (“TDMA”), Frequency Division Multiple Access (“FDMA”), Orthogonal Frequency Division Multiple Access (“OFDMA”), Code Division Multiple Access (“CDMA”), or any number of other schemes. 
         [0035]    In a given satellite spot beam, all customers serviced by the spot beam may be capable of receiving all the content traversing the spot beam by virtue of the fact that the satellite communications system  100  employs wireless communications via various antennae (e.g.,  110  and  125 ). However, some of the content may not be intended for receipt by certain customers. As such, the satellite communications system  100  may use various techniques to “direct” content to a subscriber or group of subscribers. For example, the content may be tagged (e.g., using packet header information according to a transmission protocol) with a certain destination identifier (e.g., an IP address) or use different modcode points. Each subscriber terminal  130  may then be adapted to handle the received data according to the tags. For example, content destined for a particular subscriber terminal  130  may be passed on to its respective CPE  160 , while content not destined for the subscriber terminal  130  may be ignored. In some cases, the subscriber terminal  130  caches information not destined for the associated CPE  160  for use if the information is later found to be useful in avoiding traffic over the satellite link. 
         [0036]      FIG. 2  shows a simplified block diagram  200  illustrating an embodiment of a gateway  115  coupled between the network  120  and an antenna  110 , according to various embodiments. The gateway  115  has a number of components, including a network interface module  210 , a satellite modem termination system (“SMTS”)  230 , and a gateway transceiver module  260 . Components of the gateway  115  may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (“ASICs”) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing units (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (“FPGAs”) and other Semi-Custom ICs), which may be programmed. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific controllers. 
         [0037]    Embodiments of the gateway  115  receive data from the network  120  (e.g., the network  120  of  FIG. 1 ), including data originating from one or more origin servers  205  (e.g., content servers) and destined for one or more subscribers in a spot beam. The data is received at the network interface module  210 , which includes one or more components for interfacing with the network  120 . For example, the network interface module  210  includes a network switch and a router. 
         [0038]    In some embodiments, the network interface module  210  interfaces with other modules, including a third-party edge server  212  and/or a traffic shaper module  214 . The third-party edge server  212  may be adapted to mirror content (e.g., implementing transparent mirroring, like would be performed in a point of presence (“POP”) of a content delivery network (“CDN”)) to the gateway  115 . For example, the third-party edge server  212  may facilitate contractual relationships between content providers and service providers to move content closer to subscribers in the satellite communication network  100 . The traffic shaper module  214  controls traffic from the network  120  through the gateway  115 , for example, to help optimize performance of the satellite communication system  100  (e.g., by reducing latency, increasing effective bandwidth, etc.). In one embodiment, the traffic shaper module  214  delays packets in a traffic stream to conform to a predetermined traffic profile. 
         [0039]    Traffic is passed from the network interface module  210  to the SMTS  230  to be handled by one or more of its component modules. In some embodiments, the SMTS  230  includes a gateway accelerator module  250 , a scheduler module  235 , and support modules  246 . In some embodiments, all traffic from the network interface module  210  is passed to the gateway accelerator module  250  for handling, as described more fully below. In other embodiments, some or all of the traffic from the gateway accelerator module  250  is passed to the support modules  246 . For example, in one embodiment, real-time types of data (e.g., User Datagram Protocol (“UDP”) data traffic, like Internet-protocol television (“IPTV”) programming) bypass the gateway accelerator module  250 , while non-real-time types of data (e.g., Transmission Control Protocol (“TCP”) data traffic, like web video) are routed through the gateway accelerator module  250  for processing. 
         [0040]    Embodiments of the gateway accelerator module  250  provide various types of application, WAN/LAN, and/or other acceleration functionality. In one embodiment, the gateway accelerator module  250  implements functionality of AcceleNet applications from Intelligent Compression Technologies, Inc. (“ICT”), a division of ViaSat, Inc. This functionality may be used to exploit information from application layers of the protocol stack (e.g., layers  4 - 7  of the IP stack) through use of software or firmware operating in the subscriber terminal  130  and/or CPE  160 . 
         [0041]    Embodiments of the gateway accelerator module  250  also include a gateway parser module  252 , a gateway prefetcher module  254 , and/or a gateway masker module  246 . The gateway parser module  252  provides various script parsing functions for supporting functionality of the gateway accelerator module  250 . For example, the gateway parser module  252  may be configured to implement advanced parsing of Java scripts to interpret web requests for use in prefetching. 
         [0042]    Prefetching functionality may be implemented through the gateway prefetcher module  254  in the gateway accelerator module  250 . Embodiments of the gateway prefetcher module  254  handle one or more of various prefetching functions, including receiving and interpreting instructions from other components of the gateway accelerator module  250  as to what objects to prefetch, receiving and interpreting instructions from components of the subscriber terminal  130 , generating and/or sending instructions to one or more content servers to retrieve prefetch objects, keeping track of prefetched and/or cached content, directing objects to be cached (e.g., in the gateway cache module  220 ), etc. 
         [0043]    In some embodiments, functionality of the gateway prefetcher module  254  and/or the gateway parser module  252  is optimized by other components of the gateway accelerator module  250 . For example, requested URLs embedded in Java script may be parsed by the gateway parser module  252 , and related objects may be prefetched by the gateway prefetcher module  254 . However, certain cache-busting techniques may limit the effectiveness of the gateway prefetcher module  254  (e.g., by fooling the gateway parser module  252 ). Embodiments of the gateway masker module  246  are configured to implement URL masking to counter these cache-busting techniques, as discussed more fully below. 
         [0044]    In some embodiments, the gateway accelerator module  250  is adapted to provide high payload compression. For example, the gateway accelerator module  250  may compress payload such that over 70% of upload traffic when browsing the web in some cases is being used by transport management, and other items other than the compressed payload data. In other embodiments, functionality of the gateway accelerator module  250  is closely integrated with the satellite link through components of the SMTS  230  to reduce upload bandwidth requirements and/or to more efficiently schedule to satellite link (e.g., by communicating with the scheduler module  235 ). For example, the link layer may be used to determine whether packets are successfully delivered, and those packets can be tied more closely with the content they supported through application layer information. In certain embodiments, these and/or other functions of the gateway accelerator module  250  are provided by a proxy server  255  resident on (e.g., or in communication with) the gateway accelerator module  250 . 
         [0045]    In some embodiments, the proxy server  255  is implemented with multiple servers. Each of the multiple servers may be configured to handle a portion of the traffic passing through the gateway accelerator module  250 . It is worth noting that functionality of various embodiments described herein use data which, at times, may be processed across multiple servers. As such, one or more server management modules may be provided for processing (e.g., tracking, routing, partitioning, etc.) data across the multiple servers. For example, when one server within the proxy server  255  receives a request from a subscriber terminal  130  on the spot beam, the server management module may process that request in the context of other similar requests received at other severs in the proxy server  255 . 
         [0046]    Data processed by the gateway accelerator module  250  may pass through the support modules  246  to the scheduler  235 . Embodiments of the support modules  246  include one or more types of modules for supporting the functionality of the SMTS  230 , for example, including a multicaster module  240 , a fair access policy (“FAP”) module, and an adaptive coding and modulation (“ACM”) module. In certain embodiments, some or all of the support modules  246  include off-the-shelf types of components. 
         [0047]    Embodiments of the multicaster module  240  provide various functions relating to multicasting of data over the links of the satellite communication system  100 . Certain embodiments of the multicaster module  240  use data generated by other components of the SMTS  230  (e.g., the gateway accelerator module  250 ) to prepare traffic for multicasting. For example, the multicaster module  240  may prepare datagrams as a multicast stream. Other embodiments of the multicaster module  240  perform more complex multicasting-related functionality. For example, the multicaster module  240  may contribute to determinations of whether data is unicast or multicast to one or more subscribers (e.g., using information generated by the gateway accelerator module  250 ), what modcodes to use, whether data should or should not be sent as a function of data cached as destination subscriber terminals  130 , how to handle certain types of encryption, etc. 
         [0048]    Embodiments of the FAP module  242  implement various FAP-related functions. In one embodiment, the FAP module  242  collects data from multiple components to determine how much network usage to attribute to a particular subscriber. For example, the FAP module  242  may determine how to count upload or download traffic against a subscriber&#39;s FAP. In another embodiment, the FAP module  242  dynamically adjusts FAPs according to various network link and/or usage conditions. For example, the FAP module  242  may adjust FAPs to encourage network usage during lower traffic times. In yet another embodiment, the FAP module  242  affects the operation of other components of the SMTS  230  as a function of certain FAP conditions. For example, the FAP module  242  may direct the multicaster module  240  to multicast certain types of data or to prevent certain subscribers from joining certain multicast streams as a function of FAP considerations. 
         [0049]    Embodiments of the ACM module  244  implement various ACM functions. For example, the ACM module  244  may track link conditions for certain spot beams, subscribers, etc., for use in dynamically adjusting modulation and/or coding schemes. In some embodiments, the ACM module  244  may help determine which subscribers should be included in which customer groupings or multicast streams as a function of optimizing resources through modcode settings. In certain embodiments, the ACM module  244  implements ACM-aware encoding of data adapted for progressive encoding. For example, MPEG-4 video data may be adapted for progressive encoding in layers (e.g., a base layer and enhancement layers). The ACM module  244  may be configured to set an appropriate modcode separately for each layer to optimize video delivery. 
         [0050]    When traffic has been processed by the gateway accelerator module  250  and/or the support modules  246 , the traffic is passed to the scheduler module  235 . Embodiments of the scheduler module  235  are configured to provide various functions relating to scheduling the links of the satellite communication system  100  handled by the gateway  115 . For example, the scheduler module  235  may manage link bandwidth by scheduling license grants within a spot beam. 
         [0051]    In some embodiments, functionality of the SMTS  230  involves communication and interaction with a storage area network  222  (“SAN”). Embodiments of the SAN  222  include a gateway cache module  220 , which may include any useful type of memory store for various types of functionality of the gateway  115 . For example, the gateway cache module  220  may include volatile or non-volatile storage, servers, files, queues, etc. In certain embodiments, the SAN  222  further includes a captive edge server  225 , which may be in communication with the gateway cache module  220 . In some embodiments, the captive edge server  225  provides functionality similar to that of the third-party edge server  212 , including content mirroring. For example, the captive edge server  225  may facilitate different contractual relationships from those of the third-party edge server  212  (e.g., between the gateway  115  provider and various content providers). 
         [0052]    It will be appreciated that the SMTS  230  provides many different types of functionality. For example, embodiments of the SMTS  230  oversee a variety of decoding, interleaving, decryption, and unscrambling techniques. The SMTS  230  may also manage functions applicable to the communication of content downstream through the satellite  105  to one or more subscriber terminals  130 . As described more fully below with reference to various embodiments, the SMTS may handle different types of traffic in different ways (e.g., for different use cases of the satellite communication network  100 ). For example, some use cases involve contractual relationships and/or obligations with third-party content providers to interface with their edge servers (e.g., through the third-party edge server  212 ), while other use cases involve locally “re-hosting” certain content (e.g., through the captive edge server  225 ). Further, some use cases handle real-time types of data (e.g., UDP data) differently from non-real-time types of data (e.g., TCP data). Many other types of use cases are possible. 
         [0053]    In certain embodiments, some or all of these downstream communication functions are handled by the gateway transceiver module  260 . Embodiments of the gateway transceiver module  260  encode and/or modulate data, using one or more error correction techniques, adaptive encoding techniques, baseband encapsulation, frame creation, etc. (e.g., using various modcodes, lookup tables, etc.). Other functions may also be performed by these components (e.g., by the SMTS  230 ), including upconverting, amplifying, filtering, tuning, tracking, etc. The gateway transceiver module  260  communicates data to one or more antennae  110  for transmission via the satellite  105  to the subscriber terminals  130 . 
         [0054]      FIG. 3  shows a simplified block diagram  300  illustrating an embodiment of a subscriber terminal  130  coupled between the respective subscriber antenna  125  and the CPE  160 , according to various embodiments. The subscriber terminal  130  includes a terminal transceiver module  310 , data processing modules  315 , and a terminal cache module  335 - a . Embodiments of the data processing modules  315  include a MAC module  350 , a terminal accelerator module  330 , and a routing module  320 . 
         [0055]    The components may be implemented, in whole or in part, in hardware. Thus, they may comprise one, or more, Application Specific Integrated Circuits (“ASICs”) adapted to perform a subset of the applicable functions in hardware. Alternatively, the functions may be performed by one or more other processing modules (or cores), on one or more integrated circuits. In other embodiments, other types of integrated circuits may be used (e.g., Structured/Platform ASICs, Field Programmable Gate Arrays (“FPGAs”) and other Semi-Custom ICs), which may be programmed. Each may also be implemented, in whole or in part, with instructions embodied in a computer-readable medium, formatted to be executed by one or more general or application specific processors. 
         [0056]    A signal from the subscriber antenna  125  is received by the subscriber terminal  130  at the terminal transceiver module  310 . Embodiments of the terminal transceiver module  310  may amplify the signal, acquire the carrier, and/or downconvert the signal. In some embodiments, this functionality is performed by other components (either inside or outside the subscriber terminal  130 ). 
         [0057]    In some embodiments, data from the terminal transceiver module  310  (e.g., the downconverted signal) is communicated to the data processing modules  315  for processing. For example, data is communicated to the MAC module  350 . Embodiments of the MAC module  350  prepare data for communication to other components of, or in communication with, the subscriber terminal  130 , including the terminal accelerator module  330 , the routing module  320 , and/or the CPE  160 . For example, the MAC module  350  may modulate, encode, filter, decrypt, and/or otherwise process the data to be compatible with the CPE  160 . 
         [0058]    In some embodiments, the MAC module  350  includes a pre-processing module  352 . The pre-processing module  352  implements certain functionality for optimizing the other components of the data processing modules  315 . In some embodiments, the pre-processing module  352  processes the signal received from the terminal transceiver module by interpreting (e.g., and decoding) modulation and/or coding schemes, interpreting multiplexed data streams, filtering the digitized signal, parsing the digitized signal into various types of information (e.g., by extracting the physical layer header), etc. In other embodiments, the pre-processing module  352  pre-filters traffic to determine which data to route directly to the routing module  320 , and which data to route through the terminal accelerator module  330  for further processing. 
         [0059]    Embodiments of the terminal accelerator module  330  provide substantially the same functionality as the gateway accelerator module  250 , including various types of applications, WAN/LAN, and/or other acceleration functionality. In one embodiment, the terminal accelerator module  330  implements functionality of AcceleNet™ applications, like interpreting data communicated by the gateway  115  using high payload compression, handling various prefetching functions, parsing scripts to interpret requests, etc. In certain embodiments, these and/or other functions of the terminal accelerator module  330  are provided by a proxy client  332  resident on (e.g., or in communication with) the terminal accelerator module  330 . Data from the MAC module  350  and/or the terminal accelerator module  330  may then be routed to one or more CPEs  160  by the routing module  320 . 
         [0060]    In some embodiments, the terminal accelerator module  330  includes a terminal prefetcher module  334 , a terminal parser module  342 , and/or a terminal masker module  340 . In various embodiments, the terminal parser module  342 , the terminal prefetcher module  334 , and the terminal masker module  340  provide the same or similar functionality as the gateway parser module  252 , the gateway prefetcher module  254 , and the gateway masker module  246 , respectively. For example, similar modules in the terminal accelerator module  330  and the gateway accelerator module  250  may work together to implement their respective functions. In other embodiments, the components of the subscriber terminal  130  and the gateway  115  provide different functionality. For example, functionality of the gateway parser module  252  may be asymmetric, such that it would not be desirable or possible to provide the same functionality in the terminal parser module  342 . In some embodiments, the terminal accelerator module  330  further includes a prefetch list  336 . 
         [0061]    In some embodiments, output from the data processing module  320  and/or the terminal accelerator module  330  is stored in the terminal cache module  335 - a . Further, the data processing module  320  and/or the terminal accelerator module  330  may be configured to determine what data should be stored in the terminal cache module  335 - a  and which data should not (e.g., which data should be passed to the CPE  160 ). It will be appreciated that the terminal cache module  335 - a  may include any useful type of memory store for various types of functionality of the subscriber terminal  130 . For example, the terminal cache module  335 - a  may include volatile or non-volatile storage, servers, files, queues, etc. 
         [0062]    In certain embodiments, storage functionality and/or capacity is shared between an integrated (e.g., on-board) terminal cache module  335 - a  and an extended (e.g., off-board) cache module  335 - b . For example, the extended cache module  335 - b  may be implemented in various ways, including as an attached peripheral device (e.g., a thumb drive, USB hard drive, etc.), a wireless peripheral device (e.g., a wireless hard drive), a networked peripheral device (e.g., a networked server), etc. In some embodiments, the subscriber terminal  130  interfaces with the extended cache module  335 - b  through one or more ports  338 . In one embodiment, functionality of the terminal cache module  335 - a  is implemented as storage integrated into or in communication with the CPE  160  of  FIG. 1 . 
         [0063]    Some embodiments of the CPE  160  are standard CPE  160  devices or systems with no specifically tailored hardware or software (e.g., shown as CPE  160 - a ). Other embodiments of the CPE  160 , however, include hardware and/or software modules adapted to optimize or enhance integration of the CPE  160  with the subscriber terminal  130  (e.g., shown as alternate CPE  160 - b ). For example, the alternate CPE  160 - b  is shown to include a CPE accelerator module  362 , a CPE processor module  366 , and a CPE cache module  364 . Embodiments of the CPE accelerator module  362  are configured to implement the same, similar, or complimentary functionality as the terminal accelerator module  330 . For example, the CPE accelerator module  362  may be a software client version of the terminal accelerator module  330 . In some embodiments, some or all of the functionality of the data processing modules  315  is implemented by the CPE accelerator module  362  and/or the CPE processor module. In these embodiments, it may be possible to reduce the complexity of the subscriber terminal by shifting functionality to the alternate CPE  160 - b . Embodiments of the CPE cache module  364  may include any type of data caching components in or in communication with the alternate CPE  160 - b  (e.g., a computer hard drive, a digital video recorder (“DVR”), etc.). In some embodiments, the CPE cache module  364  is in communication with the extended cache module  335 - b , for example, via one or more ports  338 - b.    
         [0064]    In certain embodiments, the subscriber terminal  130  is configured to transmit data back to the gateway  115 . Embodiments of the data processing modules  315  and the terminal transceiver module  310  are configured to provide functionality for communicating information back through the satellite communication system  100  (e.g., for directing provision of services). For example, information about what is stored in the terminal cache module  335 - a  or the CPE cache module  364  may be sent back to the gateway  115  for limiting repetitious file transfers, as described more fully below. 
         [0065]    It will be appreciated that the satellite communications system  100  may be used to provide different types of communication services to subscribers. For example, the satellite communications system  100  may provide content from the network  120  to a subscriber&#39;s CPE  160 , including Internet content, broadcast television and radio content, on-demand content, voice-over-Internet-protocol (“VoIP”) content, and/or any other type of desired content. It will be further appreciated that this content may be communicated to subscribers in different ways, including through unicast, multicast, broadcast, and/or other communications. 
         [0066]    Embodiments include methods, systems, and devices that implement various techniques for optimizing web access over satellite communication links. It will be appreciated that other components and systems may be used to provide functionality of the various embodiments described herein. As such, descriptions of various embodiments in the context of components and functionality of  FIGS. 1-3  are intended only for clarity, and should not be construed as limiting the scope of the invention. 
         [0067]    For example, embodiments of the invention may be used to address certain cold access metrics. Cold access (e.g., a first visit to a website with a clear cache) to popular websites is a well-established metric for user experience on a public network, as it is the operation in which network performance is most clearly and frequently apparent to the end user. Consequently, improvements in this cold access metric can play a role in driving consumer purchasing decisions, such as in selecting network access providers or deciding whether to use an acceleration service. There are a number of factors that may contribute to the cold access metric. 
         [0068]    Some factors that may contribute to the cold access metric relate to the number of round trip times (“RTTs”) needed to communicate content between elements of the satellite systems (e.g., between the gateway  115  and the subscriber terminal  130  of the satellite communication system  100  of  FIG. 1 ). Because of the large distance that must be traveled to and from the satellite  105 , some data latency is inherent in any satellite communication system  100 . This latency may be increased with each RTT needed to fulfill a request for data. As such, reducing the number of RTTs needed to communicate information over the satellite communication system  100  may significantly reduce the data transfer times (e.g., download times) over the communication links. 
         [0069]    Other factors that may contribute to the cold access metric relate to delays caused by waiting for content from upstream servers. For example, the gateway prefetcher module  254  and/or the terminal prefetcher module  334  may be capable of determining from a website request how to prefetch much of the content for the website (e.g., through intelligent script parsing). However, receipt of the prefetched content may be delayed while the gateway  115  (e.g., acting as a proxy server) waits for responses from origin servers serving the website content. These delays may substantially offset reductions in delay provided by the prefetching functionality of the gateway prefetcher module  254  and/or the terminal prefetcher module  334 . 
         [0070]    Embodiments of the invention implement various types of functionality to address these and other factors to optimize web access performance. Some embodiments use acceleration functionality like advanced prefetching and compression (e.g., through the gateway accelerator module  250  and/or the terminal accelerator module  330 ) to reduce the number of RTTs. Other embodiments use uniform resource locator (“URL”) anti-aliasing and/or cycle caching functionality to enhance performance of the satellite communication system  100  without substantially interfering with the commercial objectives of the content providers. Still other embodiments provide improved parsing functionality to optimize prefetching results. 
         [0071]      FIG. 4  provides a schematic illustration of one embodiment of a computer system  400  that can perform the methods of the invention, as described herein, and/or can function as, for example, gateway  115 , subscriber terminal  130 , etc. It should be noted that  FIG. 4  is meant only to provide a generalized illustration of various components, any or all of which may be utilized as appropriate.  FIG. 4 , therefore, broadly illustrates how individual system elements may be implemented in a relatively separated or relatively more integrated manner. 
         [0072]    The computer system  400  is shown comprising hardware elements that can be electrically coupled via a bus  405  (or may otherwise be in communication, as appropriate). The hardware elements can include one or more processors  410 , including without limitation one or more general-purpose processors and/or one or more special-purpose processors (such as digital signal processing chips, graphics acceleration chips, and/or the like); one or more input devices  415 , which can include without limitation a mouse, a keyboard and/or the like; and one or more output devices  420 , which can include without limitation a display device, a printer and/or the like. 
         [0073]    The computer system  400  may further include (and/or be in communication with) one or more storage devices  425 , which can comprise, without limitation, local and/or network accessible storage and/or can include, without limitation, a disk drive, a drive array, an optical storage device, a solid-state storage device, such as a random access memory (“RAM”) and/or a read-only memory (“ROM”), which can be programmable, flash-updateable and/or the like. The computer system  400  might also include a communications subsystem  430 , which can include without limitation a modem, a network card (wireless or wired), an infra-red communication device, a wireless communication device and/or chipset (such as a Bluetooth™ device, an 802.11 device, a WiFi device, a WiMax device, cellular communication facilities, etc.), and/or the like. The communications subsystem  430  may permit data to be exchanged with a network (such as the network described below, to name one example), and/or any other devices described herein. In many embodiments, the computer system  400  will further comprise a working memory  435 , which can include a RAM or ROM device, as described above. 
         [0074]    The computer system  400  also can comprise software elements, shown as being currently located within the working memory  435 , including an operating system  440  and/or other code, such as one or more application programs  445 , which may comprise computer programs of the invention, and/or may be designed to implement methods of the invention and/or configure systems of the invention, as described herein. Merely by way of example, one or more procedures described with respect to the method(s) discussed above might be implemented as code and/or instructions executable by a computer (and/or a processor within a computer). A set of these instructions and/or codes might be stored on a computer-readable storage medium, such as the storage device(s)  425  described above. In some cases, the storage medium might be incorporated within a computer system, such as the system  400 . In other embodiments, the storage medium might be separate from a computer system (e.g., a removable medium, such as a compact disc, etc.), and/or provided in an installation package, such that the storage medium can be used to program a general purpose computer with the instructions/code stored thereon. These instructions might take the form of executable code, which is executable by the computer system  400  and/or might take the form of source and/or installable code, which, upon compilation and/or installation on the computer system  400  (e.g., using any of a variety of generally available compilers, installation programs, compression/decompression utilities, etc.) then takes the form of executable code. 
         [0075]    It will be apparent to those skilled in the art that substantial variations may be made in accordance with specific requirements. For example, customized hardware might also be used, and/or particular elements might be implemented in hardware, software (including portable software, such as applets, etc.), or both. Further, connection to other computing devices such as network input/output devices may be employed. 
         [0076]    In one aspect, the invention employs a computer system (such as the computer system  400 ) to perform methods of the invention. According to a set of embodiments, some or all of the procedures of such methods are performed by the computer system  400  in response to processor  410  executing one or more sequences of one or more instructions (which might be incorporated into the operating system  440  and/or other code, such as an application program  445 ) contained in the working memory  435 . Such instructions may be read into the working memory  435  from another machine-readable medium, such as one or more of the storage device(s)  425 . Merely by way of example, execution of the sequences of instructions contained in the working memory  435  might cause the processor(s)  410  to perform one or more procedures of the methods described herein. 
         [0077]    The terms “machine-readable medium” and “computer readable medium”, as used herein, refer to any medium that participates in providing data that causes a machine to operate in a specific fashion. In an embodiment implemented using the computer system  400 , various machine-readable media might be involved in providing instructions/code to processor(s)  410  for execution and/or might be used to store and/or carry such instructions/code (e.g., as signals). In many implementations, a computer-readable medium is a physical and/or tangible storage medium. Such a medium may take many forms, including but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical or magnetic disks, such as the storage device(s)  425 . Volatile media includes, without limitation, dynamic memory, such as the working memory  435 . Transmission media includes coaxial cables, copper wire and fiber optics, including the wires that comprise the bus  405 , as well as the various components of the communication subsystem  430  (and/or the media by which the communications subsystem  430  provides communication with other devices). Hence, transmission media can also take the form of waves (including without limitation radio, acoustic and/or light waves, such as those generated during radio-wave and infra-red data communications). 
         [0078]    Common forms of physical and/or tangible computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, or any other magnetic medium, a CD-ROM, any other optical medium, punchcards, papertape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EPROM, any other memory chip or cartridge, a carrier wave as described hereinafter, or any other medium from which a computer can read instructions and/or code. 
         [0079]    Various forms of machine-readable media may be involved in carrying one or more sequences of one or more instructions to the processor(s)  410  for execution. Merely by way of example, the instructions may initially be carried on a magnetic disk and/or optical disc of a remote computer. A remote computer might load the instructions into its dynamic memory and send the instructions as signals over a transmission medium to be received and/or executed by the computer system  400 . These signals, which might be in the form of electromagnetic signals, acoustic signals, optical signals and/or the like, are all examples of carrier waves on which instructions can be encoded, in accordance with various embodiments of the invention. 
         [0080]    The communications subsystem  430  (and/or components thereof) generally will receive the signals, and the bus  405  then might carry the signals (and/or the data, instructions, etc., carried by the signals) to the working memory  435 , from which the processor(s)  405  retrieves and executes the instructions. The instructions received by the working memory  435  may optionally be stored on a storage device  425  either before or after execution by the processor(s)  410 . 
         [0081]    A set of embodiments comprises systems for managing identity information and generating an identity confidence scoring system. Merely by way of example,  FIG. 5  illustrates a schematic diagram of a system  500  that can be used in accordance with one set of embodiments. The system  500  can include one or more user computers  505 . The user computers  505  can be general purpose personal computers (including, merely by way of example, personal computers and/or laptop computers running any appropriate flavor of Microsoft Corp.&#39;s Windows™ (e.g., Vista™) and/or Apple Corp.&#39;s Macintosh™ operating systems) and/or workstation computers running any of a variety of commercially available UNIX™ or UNIX-like operating systems. These user computers  505  can also have any of a variety of applications, including one or more applications configured to perform methods of the invention, as well as one or more office applications, database client and/or server applications, and web browser applications. Alternatively, the user computers  505  can be any other electronic device, such as a thin-client computer, Internet-enabled mobile telephone, and/or personal digital assistant (PDA), capable of communicating via a network (e.g., the network  510  described below) and/or displaying and navigating web pages or other types of electronic documents. Although the exemplary system  500  is shown with three user computers  505 , any number of user computers can be supported. 
         [0082]    Certain embodiments of the invention operate in a networked environment, which can include a network  510 . The network  510  can be any type of network familiar to those skilled in the art that can support data communications using any of a variety of commercially available protocols, including without limitation TCP/IP, SNA, IPX, AppleTalk, and the like. Merely by way of example, the network  510  can be a local area network (“LAN”), including without limitation an Ethernet network, a Token-Ring network and/or the like; a wide-area network (WAN); a virtual network, including without limitation a virtual private network (“VPN”); the Internet; an intranet; an extranet; a public switched telephone network (“PSTN”); an infra-red network; a wireless network, including without limitation a network operating under any of the IEEE 802.11 suite of protocols, the Bluetooth™ protocol known in the art, and/or any other wireless protocol; and/or any combination of these and/or other networks. 
         [0083]    Embodiments of the invention can include one or more server computers  515 . Each of the server computers  515  may be configured with an operating system, including without limitation any of those discussed above, as well as any commercially (or freely) available server operating systems. Each of the servers  515  may also be running one or more applications, which can be configured to provide services to one or more clients  505  and/or other servers  515 . 
         [0084]    Merely by way of example, one of the servers  515  may be a web server, which can be used, merely by way of example, to process requests for web pages or other electronic documents from user computers  505 . The web server can also run a variety of server applications, including HTTP servers, FTP servers, CGI servers, database servers, Java™ servers, and the like. In some embodiments of the invention, the web server may be configured to serve web pages that can be operated within a web browser on one or more of the user computers  505  to perform methods of the invention. 
         [0085]    The server computers  515 , in some embodiments, might include one or more application servers, which can include one or more applications accessible by a client running on one or more of the client computers  505  and/or other servers  515 . Merely by way of example, the server(s)  515  can be one or more general purpose computers capable of executing programs or scripts in response to the user computers  505  and/or other servers  515 , including without limitation web applications (which might, in some cases, be configured to perform methods of the invention). Merely by way of example, a web application can be implemented as one or more scripts or programs written in any suitable programming language, such as Java™, C, C#™ or C++, and/or any scripting language, such as Perl, Python, or TCL, as well as combinations of any programming/scripting languages. The application server(s) can also include database servers, including without limitation those commercially available from Oracle™, Microsoft™, Sybase™, IBM™ and the like, which can process requests from clients (including, depending on the configuration, database clients, API clients, web browsers, etc.) running on a user computer  505  and/or another server  515 . In some embodiments, an application server can create web pages dynamically for displaying the information in accordance with embodiments of the invention. Data provided by an application server may be formatted as web pages (comprising HTML, Javascript, etc., for example) and/or may be forwarded to a user computer  505  via a web server (as described above, for example). Similarly, a web server might receive web page requests and/or input data from a user computer  505  and/or forward the web page requests and/or input data to an application server. In some cases, a web server may be integrated with an application server. 
         [0086]    In accordance with further embodiments, one or more servers  515  can function as a file server and/or can include one or more of the files (e.g., application code, data files, etc.) necessary to implement methods of the invention incorporated by an application running on a user computer  505  and/or another server  515 . Alternatively, as those skilled in the art will appreciate, a file server can include all necessary files, allowing such an application to be invoked remotely by a user computer  505  and/or server  515 . It should be noted that the functions described with respect to various servers herein (e.g., application server, database server, web server, file server, etc.) can be performed by a single server and/or a plurality of specialized servers, depending on implementation-specific needs and parameters. 
         [0087]    In certain embodiments, the system can include one or more databases  520 . The location of the database(s)  520  is discretionary: merely by way of example, a database  520   a  might reside on a storage medium local to (and/or resident in) a server  515   a  (and/or a user computer  505 ). Alternatively, a database  520   b  can be remote from any or all of the computers  505 ,  515 , so long as the database can be in communication (e.g., via the network  510 ) with one or more of these. In a particular set of embodiments, a database  520  can reside in a storage-area network (“SAN”) familiar to those skilled in the art. (Likewise, any necessary files for performing the functions attributed to the computers  505 ,  515  can be stored locally on the respective computer and/or remotely, as appropriate.) In one set of embodiments, the database  520  can be a relational database, such as an Oracle™ database, that is adapted to store, update, and retrieve data in response to SQL-formatted commands. The database might be controlled and/or maintained by a database server, as described above, for example. 
         [0088]    Public web sites may deploy Java scripts that make each request for an object appear with a unique URL. For example, this technique allows cycling of ad content and also prevents caches from interfering with the accounting of site accesses. These so-called “cache-busting” techniques may limit prefetching functionality (e.g., functionality of the gateway prefetcher module  254  and/or the terminal prefetcher module  334 ), as the URL prefetched on the proxy server will often not match the one from the browser. For example, to protect their commercial interests with respect to delivery and accounting of advertising content, commercial websites employ a number of cache-busting techniques. 
         [0089]    One illustrative cache-busting technique uses functions, such as random number generators and millisecond timestamps, to produce unique values each time they are executed. These unique values may then be used as part of a URL to generate unique URLs with each subsequent request for the same website. For example, an illustrative Java script for generating a URL is as follows: 
         [0000]    
       
         
               
               
             
           
               
                   
                   
               
             
             
               
                   
                 if (cacheBust) 
               
               
                   
                 { var cacheStamp = new Date( ); 
               
               
                   
                  var cacheBuster = cacheStamp.getTime( ); 
               
               
                   
                  xmlURL = 
               
               
                   
                  http://sports.myNetwork.com/ login/loggedIn?rand=‘+cacheBuster; 
               
               
                   
                 } 
               
               
                   
                   
               
             
          
         
       
     
         [0090]    The time string appended to the URL is an integer with millisecond precision, so that no two calls to this routine may ever result in the same URL string. As such, with each subsequent call to the URL, a parser (e.g., the terminal parser module  342 ) may parse the request as looking for a new (i.e., not cached) set of content, causing the terminal prefetcher module  334  to direct multiple sequential accesses from content servers (e.g., via the gateway prefetcher module  254 ). It will be appreciated that each subsequent request for the same content may necessitate additional RTTs, adding latency to data transfers. 
         [0091]    Turning now to  FIG. 6  which illustrates a system for optimizing transfer of content from the Internet to a web browser. In one embodiment, the system may include a user system  602 , a proxy client  612  and a proxy server  632 . The user system may include a client graphical user interface (GUI)  610 . Client GUI  610  may allow a user to configure performance aspects of system  600 . For example, the user may adjust the compression parameters and/or algorithms, content filters (e.g., blocks elicit websites), and enable or disable various features used by system  600 . In one embodiment, some of the features may include network diagnostics, error reporting, as well as controlling, for example, prefetch response abort  642 . Such control may be adding and/or removing pages (i.e. URLs) to or from whitelist  648  and/or blacklist  649 . 
         [0092]    In one embodiment, the user selects a universal recourse locator (URL) address which directs web browser  606  (e.g., Internet Explorer®, Firefox®, Netscape Navigator®, etc.) to a website (e.g., cnn.com, google.com, yahoo.com, etc.). In a further embodiment, web browser  606  may check browser cache  604  to determine whether the website associated with the selected URL is located within browser cache  604 . If the website is located within browser cache  604  the amount of time the website has been in the cache is checked to determine if the cached website is “fresh” (i.e. new) enough to use. For example, the amount of time that a website may be considered fresh may be 5 minutes; however, other time limits may be used. Consequently, if the website has been cached and the website is considered fresh, then web browser  606  renders the cached page. However, if the website has either not been cached or the cached webpage is not fresh, web browser  606  sends a request to the Internet for the website. 
         [0093]    In one embodiment, redirector  608  intercepts the request sent from web browser  606 . Redirector  608  instead sends the request through a local bus  605  to proxy client  612 . In some embodiments, proxy client  612  may be implemented as a software application running on user system  602 . In an alternative embodiment, proxy client  612  may be implemented on a separate computer system and is connected to user system  602  via a high speed/low latency link (e.g., a branch office LAN subnet, etc.). In one embodiment, proxy client  612  includes a request parser  616 . Request parser  616  may check cache optimizer  614  to determine if a cached copy of the requested website may still be able to be used. Cache optimizer  614  is in communication with browser cache  604  in order to have access to cached websites. Cache optimizer  614  is able to access browser cache  604  without creating a redundant copy of the cached websites, thus requiring less storage space. 
         [0094]    According to one embodiment, cache optimizer  614  implements more effective algorithms to determine whether a cached website is fresh. In one embodiment, cache optimizer  613  may implement the cache expiration algorithms from HTTP v1.1 (i.e., RFC 2616), which may not be natively supported in browser  606 . For example, browser cache  604  may inappropriately consider a cached website as too old to use; however, cache optimizer  614  may still be able to use the cached website. More efficient use of cached websites can improve browsing efficiency by reducing the number of Internet accesses. 
         [0095]    In one embodiment, if the requested website is not able to be accessed from the cached websites, request parser  616  checks prefetch manager  620  to determine if the requested website has been prefetched. Prefetching a response is when the item is requested from the website by the accelerator prior to receiving a request from the web browser  606 . Prefetching can potentially save round-trips of data access from user system  602  to the Internet. 
         [0096]    In a further embodiment, if the requested website has not been prefetched, then request parser  616  forwards the request to a request encoder  618 . Request encoder  618  encodes the request into a compressed version of the request using one of many possible data compression algorithms. For example, these algorithms may employ a coding dictionary  622  to store strings so that data from previous web objects can be used to compress data from new pages. Accordingly, where the request for the website is 550 bytes in total, the encoded request may be as small as 50 bytes. This level of compression can save bandwidth on a connection, such as high latency link  630 . In one embodiment, high latency link  630  may be a wireless link, a cellular link, a satellite link, a dial-up link, etc. 
         [0097]    In one embodiment, after request encoder  618  generates an encoded version of the request, the encoded request is forwarded to a protocol  628 . In one embodiment, protocol  628  is Intelligent Compression Technology&#39;s® (ICT) transport protocol (ITP). Nonetheless, other protocols may be used, such as the standard transmission control protocol (TCP). In one embodiment, ITP maintains a persistent connection with proxy server  632 . The persistent connection between proxy client  612  and proxy server  632  enables system  600  to eliminate the inefficiencies and overhead costs associated with creating a new connection for each request. 
         [0098]    In one embodiment, the encoded request is forwarded from protocol  628  to request decoder  636 . Request decoder  636  uses decoder  636  which is appropriate for the encoding performed by request encoder  618 . In one embodiment, this process utilizes a coding dictionary  638  in order to translate the encoded request back into a standard format which can be accessed by the destination website. Furthermore, if the HTTP request includes a cookie (or other special instructions), such as a “referred by” or type of encoding accepted, information about the cookie or instructions may be stored in a cookie cache  655 . Request decoder  636  then transmits the decoded request to the destination website over a low latency link  656 . Low latency link  656  may be, for example, a cable modem connection, a digital subscriber line (DSL) connection, a T1 connection, a fiber optic connection, etc. 
         [0099]    In response to the request, a response parser  644  receives a response from the requested website. In one embodiment, this response may include an attachment, such as an image and/or text file. Some types of attachments, such as HTML, XML, CSS, or Java Scripts, may include references to other “in-line” objects that may be needed to render a requested web page. In one embodiment, when response parser  644  detects an attachment type that may contain such references to “in-line” objects, response parser  644  may forward the objects to a prefetch scanner  646 . 
         [0100]    In one embodiment, prefetch scanner  646  scans the attached file and identifies URLs of in-line objects that may be candidates for prefetching. For example, candidates may be identified by HTML syntax, such as the token “img src=”. In addition, objects that may be needed for the web page may also be specified in java scripts that appear within the HTML or CSS page or within a separate java script file. In one embodiment, the identified candidates are added to a candidate list. 
         [0101]    In one embodiment, for the candidate URLs prefetch scanner  646  may notify prefetch abort  642  of the context in which the object was identified, such as the type of object in which it was found and/or the syntax in which the URL occurred. This information may be used by prefetch abort  642  to determine the probability that the URL will actually be requested by browser  606 . 
         [0102]    According to a further embodiment, the candidate list is forwarded to whitelist  648  and blacklist  649 . Whitelist  648  and blacklist  649  may be used to track which URLs should be allowed to be prefetched. Based on the host (i.e. the server that is supplying the URL), the file type (e.g., application service provider (ASP) files) should not be prefetched, etc. Accordingly, whitelist  648  and blacklist  649  control prefetching behavior by indicating which URLs on the candidate list should or should not be prefetched. In many instances with certain webpages/file types prefetching may not work. In addition to ASP files, webpages which include fields or cookies may have problems with prefetching. 
         [0103]    In one embodiment, once the candidate list has been passed through whitelist  648  and blacklist  649 , a modified candidate list is generated, and then the list is forwarded to a client cache model  650 . The client cache model  650  attempts to model which items from the list will be included in browser cache  604 . As such, those items are removed from the modified candidate list. Subsequently, the updated modified candidate list is forwarded to a request synthesizer  654  which creates an HTTP request in order to prefetch each item in the updated modified candidate list. The HTTP request header may include cookies and/or other instructions appropriate to the web site and/or to browser  606 &#39;s preferences using information obtained from cookie model  652 . The prefetch HTTP requests may then be transmitted through low latency link  656  to the corresponding website. 
         [0104]    In one embodiment, response parser  644  receives a prefetch response from the website and accesses a prefetch response abort  642 . Prefetch response abort  642  is configured to determine whether the prefetched item is worth sending to user system  602 . Prefetch response abort  642  bases its decision whether to abort a prefetch on a variety of factors, which are discussed below in more detail. 
         [0105]    If the prefetch is not aborted, response parser  644  forwards the response to response encoder  640 . Response encoder  640  accesses coding dictionary  638  in order to encode the prefetched response. Response encoder  640  then forwards the encoded response through protocol  628  over high latency link  630  and then to response decoder  626 . Response decoder  626  decodes the response and forwards it to response manager  624 . In one embodiment, if the response is a prefetched response then response manager  624  creates a prefetch socket to receive the prefetched item as it is downloaded. 
         [0106]    Response manager  624  transmits the response over local bus  605  to redirector  608 . Redirector  608  then forwards the response to web browser  606  which renders the content of the response. 
         [0107]    In some embodiments (e.g., as shown in  FIGS. 2 and 3 ), the terminal accelerator module  330  includes a terminal masker module  340  and/or the gateway accelerator module  250  includes a gateway masker module  246 , adapted to implement URL masking functionality. Using URL masking functionality may allow the gateway prefetcher module  254  and/or the terminal prefetcher module  334  to operate in the context of some cache-busting techniques. 
         [0108]    Turning now to  FIG. 7A , which illustrates one embodiment of gateway accelerator module  250 . In one embodiment, parser module  252  may identify an embedded URL string within a webpage, Java Script, etc. Further, parser module  252  may then analyze the URL string to determine if a cache-busting portion (or random portion) exists in the URL string. However, it should be noted that the random portion may not have anything to do with cache busting, and is placed in the URL string for utility value. For example, an advertisement server may embed or append a string of random characters in the URL string. Such a random string of characters may be used to cycle through ads to be presented to the browser. For example, random number  1  may produce an ad for company  1 , random number  2  may produce an ad for company  2 , and so forth. 
         [0109]    The “random number” (or embedded string) may be generated in a variety of ways. For example, a rand( )method may be called to generate a binary number. Then an ASCI string may be generated from the binary number, which is then appended or embedded in the URL. Alternatively, a timestamp may be used to produce the “random” portion of the URL string. For example, the timestamp may be extended out several digits and converted into an ASCI string and appended or embedded within the URL sting. 
         [0110]    Once the cache-busting portion of the URL string has been identified, the URL string may be passed to masker module  256 . In one embodiment, the masker produces a mask that identifies which bytes in the URL string are effectively random. This may be implemented, for example, as a string of the same length as the URL where a byte is 0 if it is a normal byte and 1 if it is random. In this case, the mask can be used to exclude the random bytes in deciding whether two URLs match, such as in the C-language method: 
         [0000]                                            bool isMatch(int urlLength, char* requestUrl, char* prefetchedUrl,           char* mask)           {            for (int i=0; i&lt;urlLength; ++i)              if ((requestUrl[i] != prefetchedUrl[i]) &amp;&amp; !mask[i])                  return false            return true;           }                        
This mask can be sent to the client along with the URL string for the item that has been prefetched.
 
         [0111]    After masker module  256  has masked out the random portion of the URL string, the masked URL string is passed to prefetcher module  254 . In one embodiment, prefetcher module  254  may compare the masked URL string with URL strings of objects that have already been prefetched by prefetcher module  254 . If a match is found, then prefetcher module  254  may then notify prefetcher module  334  in terminal accelerator module  330  ( FIG. 7B ) that the object has already been prefetched, and not to prefetch it again, thus preventing sending unnecessary bytes across the link. Accordingly, the prefetched version of the object from the masked URL string is used to be rendered in the browser instead of prefetching a new object. 
         [0112]      FIG. 8  shows an illustrative flow diagram of a method  800  for implementing URL masking functionality, according to various embodiments of the invention. The method  800  begins at block  804  by identifying a URL to be prefetched. At block  808 , a portion of the URL string is identified as employing a cache-busting technique. A mask is then set, at block  812 , to mask the cache-busting portion of the URL string. The URL string may be sent at block  816  from a proxy server to a proxy client. Further, at block  820 , the mask may be sent from the proxy server to the proxy client. In certain embodiments, the proxy server is implemented in the gateway  115  (e.g., the proxy server  255  of  FIG. 2 ) and the proxy client is implemented in the subscriber terminal  130  (e.g., the proxy client  332  of  FIG. 3 ). The gateway  115  sends a list of URLs being prefetched to the subscriber terminal  130 , where prefetched content may be cached (e.g., in the terminal cache module  335 ). 
         [0113]    At block  824 , the proxy client may compare intercepted browser requests with the list of URLs to decide whether a request can be served via a prefetched object. As part of this comparison in block  824 , the proxy client applies the mask to the requested URL and/or the prefetched URL list. In this way, the proxy client is able to determine in block  828  whether the requested content is, in fact, from a non-prefetched URL; or if it is actually from the same URL employing a cache-busting technique. 
         [0114]    If the only difference is in the masked portion of the request (e.g., the masked URL request matches the masked prefetched URL), the requested object(s) may be served in block  832  using prefetched (e.g., locally cached) content. Otherwise, the requested object(s) may be served in block  836  by retrieving the objects from other locations. For example, the requested object(s) may be retrieved from the gateway cache module  220 , from a content server over the network  120 , etc. 
         [0115]    For example, a URL is identified by the gateway parser module  252  by means of parsing a Java script embedded in a web object with certain file extensions (e.g., HTML, XML, CSS, JS, or other protocols used within HTTP). Identifying the URL may involve constructing the string using various Java functions which may be defined in the web object or may be part of a library known to the parser. When constructing the string, embodiments of the gateway parser module  252  look for calls to library functions that may be used to make URLs unique each time they are constructed so as to prevent caches from fulfilling the request from copies of previously downloaded objects (e.g., known as “cache-busting”). Examples of cache-busting functions include random number generators or timers with millisecond resolution. If the parser determines that part of the URL is being constructed with characters derived from these cache-busting functions, embodiments of the gateway masker module  256  generate a mask as a function of the URL string to mask the millisecond timestamp portion of the URL string. The prefetcher issues a request to the web server for the URL that it constructs, and the URL string and mask information are sent from the gateway  115  (e.g., proxy server  255 ) to the subscriber terminal  130  (e.g., proxy client  332 ). 
         [0116]    In some embodiments, the subscriber terminal  130  receives the URL and mask at the same time as it receives the object that it was embedded in, such as the HTML page. The terminal accelerator module  330  places the URL string and mask onto a “prefetch list” of objects that are in process of being prefetched. When the accelerator receives a subsequent HTTP GET request, the parser module  342  identifies the URL being requested and asks the prefetch list  336  whether this URL is being prefetched. The prefetch list  336  iterates through all entries to see if the request is a match. In order to determine if it is a match, calls are made to the masker module  340 , supplying the request URL, the prefetched URL being tested, and the mask associated with the prefetched URL. The masker module  340  may perform a string comparison, excluding characters as a function of the mask. Embodiments return a Boolean value indicating whether the masked versions of the requested and prefetched URLs are a match. If so, the response to the CPE  160  may be filled using the prefetched object. Otherwise, the subscriber terminal  130  may request the objects from the gateway  115  (e.g., as proxy server  255 ) over the satellite communication system  100 . 
         [0117]    It will be appreciated that embodiments of the URL masking functionality may be applied both to prefetched content (e.g., to see if a prefetched object matches a client request) and to the use of cached content on the gateway cache module  220  and/or the terminal cache module  335 . Further, it will be appreciated that URL masking functionality may allow prefetchers and caches to work even when the URLs are constructed using scripts intended to block such behavior. By facilitating the use of prefetching (e.g., by the gateway prefetcher module  254  and/or the terminal prefetcher module  334 ) and local caching (e.g., at the terminal cache module  335 ), the number of RTTs may be reduced. Local caching may also reduce some server response delays that affect communications over the satellite communication system  100 . 
         [0118]    Referring next to  FIG. 9 , which illustrates a method  900  for implementing URL masking according to embodiments of the present invention. At process block  904 , Java script included in a requested page may be parsed. During the parsing of the requested page URL string within the Java script may be identified and assembled (process block  908 ). Furthermore, the process of generating the identified URL string may be analyzed (process block  912 ). 
         [0119]    In one embodiment, a determination may be made as to whether portions of the URL string were randomly generated so as to have a meaningless value (decision block  916 ). For example, the portion of the URL string may be a randomly generated number, a timestamp, etc. If no random portion of the URL is found, then the Java script is continued to be parsed. Otherwise, at process block  920 , the random or meaningless portion of the URL string is masked out/off of the URL string. 
         [0120]    Then, at process block  924 , the masked version of the URL may be checked against prefetched URL strings and/or cached URL strings to determine a match. At decision block  928 , it is determined if there is a match, and at process block  932 , the matching prefetched or cached object associated with the determined URL string is presented to the terminal. Accordingly, a cached or prefetched object is able to be used where it otherwise would have been classified as a cache miss or a non-prefetched object. 
         [0121]      FIG. 10  illustrates one embodiment of a system  1000  according to aspects of the present invention. In one embodiment, system  1000  may include a client  1005 . Client  1005  may be configured to use a web browser to access various Internet and/or intranet web pages, or to access files, emails, etc. from various types of content servers. In one embodiment, client  1005  may include a proxy client  1010  which may intercept the traffic from the browser. Client  1005  may be configured to communicate over a high latency link  1015  with proxy server  1020  using an optimized transport protocol. 
         [0122]    In one embodiment, proxy server  1020  may identify, based on a request received from proxy client  1010  via client  1005 &#39;s browser, objects that may be able to be prefetched. Furthermore, proxy server  1020  may store all of the caching instructions for all objects downloaded by proxy server  1020  on behalf of client  1005 . 
         [0123]    In one embodiment, proxy server  1020  may send a request over a low latency link  1025  to a content server  1030 . In one embodiment, low latency link  1025  may be a satellite link, a broadband link, a cable link, etc. In a further embodiment, the request may request the caching instructions for the object that may potentially be prefetched from the web server. Proxy server  1020  may then analyze the caching instructions for the object to determine if the object has been modified since it was last prefetched. Accordingly, if the object has been modified, then proxy server  1020  would download the updated version of the object from content server  1030 . Otherwise, if the previously prefetched object is still valid, no prefetching is needed. Thus, proxy server  1020  can simply use the previously prefetched object. 
         [0124]    A number of variations and modifications of the disclosed embodiments can also be used. For example, content server  1030  may be a file server, an FTP server, etc. and various web browsers may be used by client  1005 . Furthermore, the cache model may be modified to be stored, for example, at proxy client  1010 . As such, proxy client  1010  may be configured to maintain the caching instructions associated with each prefetched object. In a further embodiment, proxy client  1010  may store cached (or prefetched) objects for future access by client  1005 , or in an alternative embodiment, to be accessed by other clients and/or servers connected with client  1005 . Consequently, any component in  FIG. 10  may be configured to store prefetched (or cached) objects and/or caching instructions. 
         [0125]    In an additional embodiment, the cache model may be implemented at a separate location from client  1005  and/or client proxy  1010 . For example, the cache model may be located at a remote server, database, storage device, remote network, etc. In one embodiment, cached objects may be stored remotely from client  1005  and retrieved from the remote location upon request of the object. 
         [0126]    While the principles of the disclosure have been described above in connection with specific apparatuses and methods, it is to be clearly understood that this description is made only by way of example and not as limitation on the scope of the disclosure. Further, embodiments described with reference to functionality of the subscriber terminal  130  may be implemented by or at the gateway, and vise versa. 
         [0127]    While the invention has been described with respect to exemplary embodiments, one skilled in the art will recognize that numerous modifications are possible. For example, the methods and processes described herein may be implemented using hardware components, software components, and/or any combination thereof. Further, while various methods and processes described herein may be described with respect to particular structural and/or functional components for ease of description, methods of the invention are not limited to any particular structural and/or functional architecture but instead can be implemented on any suitable hardware, firmware and/or software configuration. Similarly, while various functionality is ascribed to certain system components, unless the context dictates otherwise, this functionality can be distributed among various other system components in accordance with different embodiments of the invention. 
         [0128]    Moreover, while the procedures comprised in the methods and processes described herein are described in a particular order for ease of description, unless the context dictates otherwise, various procedures may be reordered, added, and/or omitted in accordance with various embodiments of the invention. Moreover, the procedures described with respect to one method or process may be incorporated within other described methods or processes; likewise, system components described according to a particular structural architecture and/or with respect to one system may be organized in alternative structural architectures and/or incorporated within other described systems. Hence, while various embodiments are described with- or without-certain features for ease of description and to illustrate exemplary features, the various components and/or features described herein with respect to a particular embodiment can be substituted, added and/or subtracted from among other described embodiments, unless the context dictates otherwise. Consequently, although the invention has been described with respect to exemplary embodiments, it will be appreciated that the invention is intended to cover all modifications and equivalents within the scope of the following claims.