Abstract:
An SDN controller to provision network resources at a data plane to keep progressive downloads of multimedia files proportional to encoding rates is disclosed. Packets from a new or unknown flow being downloaded at a default rate are forwarded from an access point, or other device, to an SDN controller for analysis. If a progressive download of a multimedia file (e.g., a video file) in progress is detected, an encoding rate of frames for the multimedia file is determined. A target download rate for the multimedia file at the access point is determined based on the encoding rate, in an embodiment. Other optional factors also take into account network-wide data plane information gathered by the SDN controller from various points on the network. Additionally, a playback history for a particular multimedia file can affect the target download rate, based on whether, for example, a file is likely to be quickly halted.

Description:
RELATED APPLICATION DATA 
       [0001]    This application claims the benefit as a continuation of U.S. application Ser. No. 14/514,420, entitled Optimizing Multimedia Streaming in WLANs (Wireless Local Access Networks) and filed on Oct. 15, 2014, the contents of which is hereby incorporated in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The invention relates generally to wireless computer networking, and more specifically, to using SDN (Software-Defined Networking) to optimize video streaming in WLAN networks at a data plane. 
       BACKGROUND 
       [0003]    Video streaming is one of the most burdening applications on networks. The high data rate necessary for video, and in particular, high definition video can dominate resources used for many other types of data transfers transacted on the network. In a WLAN, access points can service data transfers for many wireless stations connecting to a wired backbone. 
         [0004]    Video files can be prohibitively burdensome if the entire file is downloaded altogether. HTTP (Hyper Text Transfer Protocol) adaptive streaming provides a technique for progressive downloading of chunks, or portions, of the video file that can be played back at a client without having the entire file present. In more detail, a video can be divided into 10 chunks, each having about 10% of the total video file. Once a first chunk has been downloaded to the client, it fills the buffer with 8 seconds of playback time, for instance. During those 8 seconds, the next chunk can be downloaded and so on. 
         [0005]    However, a download rate for progressive downloading can be aggressive and without consideration for an actual download rate necessary for an encoding rate by a streaming server. For example, a large playback device such as web-enabled television may have a fast download rate assigned due to its potential playback resolution. The selected video file, on the other hand, may have a relatively low resolution that is encoded for streaming at a bit rate much lower than assumed. 
         [0006]    One technique to address this issue is to download customized software to a station. But reconfiguration of stations running on a station is not always desirable. For instance, guests connecting to a public hot spot for only one time would be burdened with the process of downloading and installing a client. Furthermore, many computer users are weary about malicious applications downloaded from the Internet. 
         [0007]    What is needed is a robust technique to data plane provisioning of network resources more efficiently by keeping a download rate proportional to an encoding rate. 
       SUMMARY 
       [0008]    These shortcomings are addressed by the present disclosure of methods, computer program products, and systems for provisioning of network resources at a data plane to keep progressive downloads of multimedia files proportional to encoding rates. 
         [0009]    In one embodiment, packets from a new or unknown flow being downloaded at a default rate are forwarded from an access point, or other device, to an SDN (Software-Defined Networking) controller for analysis. If a progressive download of a multimedia file (e.g., a video file) in progress is detected, an encoding rate of frames for the multimedia file is determined. 
         [0010]    A target download rate for the multimedia file at the access point is determined based on the encoding rate, in an embodiment. Other optional factors also take into account network-wide data plane information gathered by the SDN controller from various points on the network. Additionally, a playback history for a particular multimedia file can affect the target download rate, based on whether, for example, a file is likely to be quickly halted. 
         [0011]    One or more OpenFlow rules (or other protocol for rules) is generated to implement the target download rate at a data plane of the access point. The one or more OpenFlow rules are implemented at the data plane of the access point, and possibly other devices along a data path, to meet the target data rate. 
         [0012]    Advantageously, network resources are more efficiently provisioned by keeping a progressive download rate proportional to an encoding rate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    In the following drawings, like reference numbers are used to refer to like elements. Although the following figures depict various examples of the invention, the invention is not limited to the examples depicted in the figures. 
           [0014]      FIG. 1  is a high-level block diagram illustrating a system to optimize multimedia downloads with an SDN controller, according to one embodiment. 
           [0015]      FIG. 2  is a more detailed block diagram illustrating the SDN controller of the system of  FIG. 1 , according to one embodiment. 
           [0016]      FIG. 3  is a more detailed block diagram illustrating an access point of the system of  FIG. 1 , according to one embodiment. 
           [0017]      FIG. 4  is a sequence diagram illustrating interactions between components of the system of  FIG. 1 , according to one embodiment. 
           [0018]      FIG. 5  is a flow diagram illustrating a method, at the SDN controller, for optimizing multimedia downloads, according to one embodiment. 
           [0019]      FIG. 6  is a flow diagram illustrating a method, at the access point, for optimizing multimedia downloads, according to one embodiment. 
           [0020]      FIG. 7  is a block diagram illustrating an exemplary computing device, according to one embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0021]    The present invention provides methods, computer program products, and systems for optimizing multimedia downloads with an SDN (Software-Defined Networking) controller. For example, video files downloading faster than necessary for a certain encoding bit rate can be slowed down using data plane operations on an access point, or other network device. Likewise, downloading can be increased as needed for an encoding bit rate. One of ordinary skill in the art will recognize that many other scenarios are possible, as discussed in more detail below. 
         [0022]    Systems to Optimize Multimedia Downloads with an SDN Controller ( FIGS. 1-4 ) 
         [0023]      FIG. 1  is a high-level block diagram illustrating a system  100  to optimize multimedia downloads with an SDN controller, according to one embodiment. The system  100  comprises SDN controller  110 , Wi-Fi controller  120 , access points  130 A- 130 N, stations  140 A-N and streaming server  150 . The components can be coupled to a network  199 , such as the Internet, a local network or a cellular network, through any suitable wired (e.g., Ethernet) or wireless (e.g., Wi-Fi or 4G) medium, or combination. In a preferred embodiment, the stations  140 A- 140 N are coupled to the access points  130 A- 130 N through wireless communication channels  115 A- 115 N, while the access points  130 A- 130 N can be coupled to the SDN and Wi-Fi controllers  110 ,  120  through wired communication channels  125 A- 125 N and to network  199  through wired communication channel  135 . Other embodiments of communication channels are possible, including a cloud-based controller, and hybrid networks. Additional network components can also be part of the system  100 , such as firewalls, virus scanners, routers, switches, application servers, databases, and the like. In general, the SDN controller  110  implements layer 2 rules at the access points  130 A- 130 N to optimize network conditions, such as throughput, latency, and the like. 
         [0024]    The SDN controller  110  can be, for example, a personal computer, a laptop computer, a server, a cloud-based device, a virtual device, or the like implemented in any of the computing devices discussed herein (e.g., see  FIG. 7 ). In operation, the SDN controller  110  can communicate with each of the access points  130 A- 130 N using the OpenFlow or other protocol to directly implement layer 2 rules to affect network behavior. More specifically, the SDN controller  110  adjusts, in one embodiment, a download rate for a particular multimedia file based on an encoding rate. OpenFlow provides cross-vendor communication as an abstraction of vendor-specific internal programming. Initially, new or unknown flows forwarded from one of the access points  130 A- 130 N are sniffed to detect a progressive download. Deep packet inspection can reveal a file name and an encoding rate of the multimedia file. One or more rules are generated with respect to the multimedia file for transmission and implementation at one or more of the access points  130 A- 130 N. Other factors that can affect a target download rate include network conditions and characteristics of the file. For example, a multimedia file that users tend to halted after a short time can be downloaded more slowly by reducing the priority. Also, a download rate can be slowed down for advertisements. Many implementation-specific scenarios are possible. 
         [0025]    More generally, the SDN controller  110  centralizes data plane decision-making for the access points  130 A- 130 N. To do so, the access points  130 A- 130 N are configured to concede layer 2 routing decisions to the SDN controller  110  by forwarding packets to the SDN controller  110  for routing instructions. The SDN controller can use input gathered across the network to make layer 2 routing decisions for the packets which are communicated back to the forwarding one of the access points  130 A- 130 N. In one embodiment, routing decisions are made as a reaction to new or unknown flows. In another embodiment, access points are pre-configured by the SDN controller with rules for automatically implementing SDN controller  110  decisions on matching packets in the future. In still another embodiment, the rules or policies are distributed to the other network devices along a routing path for multi-hop data plane control of download rates for a particular multimedia file. Updated rules can be sent at a later time. Additional embodiments of the SDN controller  110  are discussed with respect to  FIG. 2 . 
         [0026]    The Wi-Fi controller  120  can be implemented in any of the computing devices discussed herein (e.g., see  FIG. 7 ). For example, the Wi-Fi controller  120  can be an MC1500 or MC6000 device by Meru Networks of Sunnyvale, CA. Within the system  100 , the Wi-Fi controller  120  communicates with each of the access point  130 A- 130 N to manage wireless connections to the stations  140 A- 140 N using IEEE protocols. In some embodiments, BSSIDs (Basic Service Set Identifiers) are managed from the Wi-Fi controller  120  to implement functionality such as seamless mobility for transparent handoffs of stations between access points all having a common BSSID. In other functionality such as virtual port, the Wi-Fi controller  130  coordinates a uniquely-assigned BSSID for each station in order to provide individualized management of stations connected at any access point. In some embodiments, the Wi-Fi controller  120  can be an independent physical device form. Additional embodiments of the Wi-Fi controller  120  are discussed with respect to  FIG. 4 . 
         [0027]    The access points  130 A- 130 N include one or more individual access points implemented in any of the computing devices discussed herein (e.g., see  FIG. 7 ). For example, the access points  130 A- 130 N can be an AP  110  or AP  433  (modified as discussed herein) by Meru Networks of Sunnyvale, Calif. A network administrator can strategically place the access points  130 A- 130 N for optimal coverage area over a locale. The access points  130 A- 130 N can, in turn, be connected to a wired hub, switch or router connected to the network  199 . In embodiment, the access points  130 A- 130 N functionality is incorporated into a switch or router. To provide network service to the stations  140 A- 140 N, in one embodiment, the access points  130 A- 130 N comply with IEEE 802.11 protocols (promulgated by the Institute of Electrical and Electronics Engineers) to provide Wi-Fi service to the stations  140 A-N over wireless communication channels  140 A- 140 N. Under IEEE 802.11, a beacon with one or more BSSIDs is periodically sent to advertise a presence for new connections and maintain current connections. Then the access points  130 A- 130 N listen for packets addressed to associated BSSIDs and ignore packets addressed to unassociated BSSIDs. Furthermore, the access points  130 A- 130 N forward packets addressed to MAC (Media Access Control) addresses of associated stations. 
         [0028]    The access points  130 A- 130 N, without input from the SDN controller  110 , may forward packets according to a shortest route, or other standard routing or switching algorithm. Local-level conditions can be revealed by TCP (transmission control protocol). However, the SDN controller  110  has a network-wide view of layer 2 conditions and can override inherent TCP forwarding behavior as needed. In other words, the access points  130 A- 130 N may continue to make control plane decisions but data plane decisions are conceded to the SDN controller  110 , in some or all situations. Further, although the Wi-Fi controller  120  has some network-wide visibility, it is limited to Wi-Fi-relevant information for load balancing, managing a number of station connections at a particular access point, tracking BSSIDs, and the like. While the higher-layer decisions on the access points  130 A- 130 N can have some indirect impact on data plane decision making, the SDN controller  110  makes direct data plane decisions. The rules may require that file requests or responses be delayed to impeded downloading processes, and thereby, a download rate. The SDN controller  110  policies, as implemented, can override, co-exist, or compete with policies of the Wi-Fi controller  120  and the access points  130 A- 130 N. 
         [0029]    The stations  140 A- 140 N can be, for example, a personal computer, a laptop computer, a tablet computer, a smart phone, a mobile computing device, a server, a cloud-based device, a virtual device, an Internet appliance, or any of the computing devices described herein (see e.g.,  FIG. 7 ). No special client is needed for this particular technique, although other aspects of the network may require downloads to the stations  140 A- 140 N. Some video streaming services use a specific client (e.g., a mobile application) and others use native applications in an operating system or OEM applications such as a web browser. The stations  140 A- 140 N connect to the access points  130 A- 130 N for access to, for example, a LAN or external networks using an RF (radio frequency) antenna and network software complying with IEEE 802.11. In one embodiment, a user on a laptop watches videos from YouTube in real-time on a hot spot. In another embodiment, a user watches a training video on a PC connected over VPN to a cloud-based corporate server. In still another embodiment, a family watches on-demand movies on a web-enabled television. 
         [0030]    The streaming server  150  can be one or more server devices providing videos for real-time viewing or file download. YouTube videos are sent from sent streaming servers and are viewed through a player embedded in a web page of a web browser. Encoding rates can be affected by factors such as playback resolution (e.g., high-definition or standard definition), playback speed (e.g., slow motion or fast forward), network performance (e.g., ping round trip time), and playback device (e.g., smart phone or television). Once encoded, the streaming server transmits multimedia files, in one embodiment, by segmenting an individual multimedia file into multiple chunks for progressively downloading chunk-by-chunk. Numbered chunks can be transmitted serially or in parallel depending on a download rate negotiated between the streaming server  150  and a client, and then reassembled at the client. The download rate can be negotiated between the streaming server  150  one of the stations  140 A- 140 N, and the without consultation of a relevant access point  130 A- 130 N. For example, an application or web browser running on a station can request high-definition quality video streaming. In another example, based on a certain number of dropped packets or other network issues, the download rate may be renegotiated to standard quality video streaming in order to improve playback. However, these application layer negotiations can be independent of layer 2 routing decisions made at the access points  130 A- 130 N responsive to rules promulgated by the SDN controller  110 . As a result of layer 2 changes, a first chunk can be downloaded at a first rate as negotiated at an application-layer by a station and streaming server, while subsequent chunks are downloaded at a second rate as affected by data plane layer rules. Additional adjustments can be implemented with a third rate, fourth rate or other, based on updates on the system  100  (e.g., link conditions or file history). 
         [0031]      FIG. 2  is a more detailed block diagram illustrating the SDN controller  110  of the system  100 , according to one embodiment. The SDN controller  110  comprises a data plane manager  210 , a deep packet inspection engine  220 , a data plane condition module  230 , a multimedia file history database  240 , and an OpenFlow rule module  250 . The components can be implemented in hardware, software, or a combination of both. 
         [0032]    The data plane manager  210  uses a communication interface to connect with access points and other network devices around the network  100 . Access points can be registered with the SDN controller  110  manually by a network administrator or automatically by receiving notification from the Wi-Fi controller  120 . Forwarded packets and status information is received by the data plane manager  210  and rules are sent to for implementation. The data plane manager  210  can call various modules for analysis and a determination of resulting actions. Some embodiments are only concerned with matching a download rate to an encoding rate by use of the deep packet inspection engine  220 . But other embodiments use the multimedia file history database  240  to make file specific determinations, and further embodiments use the data plane condition module  230  to factor in real-time routing conditions. The data plane manager  210  can call the OpenFlow rule module  250  to generate rules to affect progressive downloads based on the analyses. Additional modules can be added for other types of analysis and action. 
         [0033]    The deep packet inspection engine  220  can sniff forwarded packets to identify multimedia files being progressively downloaded among other types of data transfers. In one example, information contained in headers is easily recognizable. In another example, information contained in the data can be pattern matched or hashed against a database for identification of applications, files, encoding rates, and the like. One example of deep packet inspection can leverage specific rules for YouTube or other types of files by being pre-programmed with rules on where in data packets to find needed information according to site-specific formatting. In one case, the deep packet inspection engine  220  calculates an encoding rate by identifying a file size from an HTTP header and a duration from a video header, such that [encoding rate]=[file size]/[duration]. Encoding rate can also be determined from empirical observation, by interrogating the streaming server  150 , and using other known techniques. 
         [0034]    The data plane condition module  230  analyzes local conditions received from various points around the network  100 , including from the access points  130 A-N. Network-level conditions can be derived from the local conditions to give a broader view of how various situations affect the network as a whole. As a result, a positive view from one part of the network  100  may cause an associated one of the access points  130 A-N to liberally grant bandwidth, while a negative view of the overall network may benefit more from more conservative grants of bandwidth to prevent further downstream burdens. 
         [0035]    The multimedia file history database  240 , in an embodiment, stores data records or tables about playbacks of particular files and/or file types. An average playback length or number of chunks provide a parameter about how much of the multimedia file that is actually utilized by an end user. Further statistics such as standards of deviation and histograms can provided deeper insight as to actual use. File types can be indicated by URL, data file format, meta tags, subject matter, user ratings, and any other appropriate category. Other type of relevant information can also be stored, such as download rate for other files at the same URL, the same access point, or the same station. 
         [0036]    The OpenFlow rule module  250  generates and stores rules for implementation at the access points  130 A-N and other network devices, for example, based on an encoding rate calculated by the deep packet inspection engine  220  and a download rate reported by an access point. The OpenFlow protocol is just one example of rule formats and can be substituted by other programming interfaces such as XML, source code, proprietary commands and the like. Examples of OpenFlow rules include Boolean style conditions. One rule can broadly impose certain conditions on all progressive downloads of multimedia files. One rule can set a minimum file size threshold for applying rules to adjust download rates. One rule can set a lowest priority for all multimedia packets addressed from unverified URLs of specifically-listed URLs. One rule can temporarily increase a delay of all standard definition video. Numerous other rules are possible. 
         [0037]      FIG. 3  is a more detailed block diagram illustrating a representative access point  130  of the system  100 , according to one embodiment. The access point  130  comprises an IEEE 802.11 beacon generation module  310 , an IEEE 802.11 station manager  320 , an SDN routing module  330 , and a packet queue  340 . The components can be implemented in hardware, software, or a combination of both. 
         [0038]    The IEEE 802.11 beacon generation module  310  generates beacons with embedded BSSIDs and parameters, according to IEEE 802.11 protocols. The IEEE 802.11 station manager  320  stores globally and/or locally-influenced parameter values, policy-based parameter values, manually configured parameter values, or the like. Wi-Fi status data related to a number of connected stations, usage data, and the like can be collected from the IEEE 802.11 beacon generation module  310  and the IEEE 802.11 station manager  320  for the SDN controller  110 . 
         [0039]    The SDN routing module  330  forwards packets and statuses to the SDN controller  110 . The first few packets from new flows can be sent to the SDN controller  110  for analysis. Alternatively, there may already be rules present that direct handling of the new flows. Example statuses can be a download rate for a specific flow, queue capacity, routing statistics, and more. Periodic updates are made on a regular basis or responsive to change. Additionally, the SDN routing module  330  also receives an implements rules in OpenFlow or other formats. The packet queue  340  stores requests for multimedia file and responsive packets being progressively downloads and flows until forwarded to an appropriate station. 
         [0040]      FIG. 4  is a sequence diagram illustrating interactions  400  between components of the system  100  of  FIG. 1 , according to one embodiment. In between the interactions, methods performed within the components of  FIG. 4  are illustrated in  FIGS. 5 and 6 . The illustrated interactions  400  are not intended to be limiting. As such, the interactions  410  to  460  can be a portion of steps from a longer process. 
         [0041]    Initially, at interaction  410 , the station  130  sends a request for a multimedia file to the streaming server  150 . At interaction  420 , the streaming server  150  responds by downloading a first chunk of the multimedia file. Although interactions  410  and  420  travel through the access point  130 , the subject technique has yet to be applied at those components. 
         [0042]    At interaction  430 , the access point  130  also sends at least a portion of the first chunk to the SDN controller  110 . In response, at interaction  440 , OpenFlow rules concerning the multimedia file are sent to the access point  130 . Subsequent chunks sent at interaction  450  are sent to the access point  130  and this time affected by the subject technique at this point. Afterwards, at interaction  460 , the subsequent chunks are sent to the station  130 . Not shown, are requests sent from station  130  to the access point  130  and affected by the subject technique prior to being forwarded to the streaming server  150 . 
         [0043]    Methods for Optimizing Multimedia Downloads in with an SDN Controller ( FIG. 5-6 ) 
         [0044]      FIG. 5  is a flow diagram illustrating a method  500 , an SDN controller, for optimizing multimedia downloads, (e.g., the SDN controller  110  of  FIG. 1 ), according to one embodiment. One of ordinary skill in the art will recognize that the method  500  is non-limiting as other embodiments can have more or less steps and can be performed in a different order. 
         [0045]    At step  510 , a progressive download of a multimedia file is detected in packets forwarded from an access point of other device. At step  520 , data plane information is received for devices across a network. At step  530 , packets are examined to determine a rate of encoding for the multimedia file. At step  540 , a target download rate for the multimedia file is determined based on the encoding rate. At step  550 , one or more rules are generated to implement the target download rate at the access point in view of network-wide data plane information and the encoding rate. At step  560 , the rules are transmitted to the access point to adjust the download rate to the target download rate. 
         [0046]      FIG. 6  is a flow diagram illustrating a method  600 , at an access point, for optimizing multimedia downloads, (e.g., the access point  130  of  FIG. 1 ), according to one embodiment. 
         [0047]    At step  610 , a new flow or unknown packets being downloaded at a target rate are detected. At step  620 , at least a portion of the packets are forwarded to the SDN controller for further instructions. At step  630 , status information about current flows and a queue capacity are sent to the SDN controller. At step  640 , rules for handling the new flow or unknown packets on the data plane are received. 
         [0048]    Generic Computing Device ( FIG. 7 ) 
         [0049]      FIG. 7  is a block diagram illustrating an exemplary computing device  700  for use in the system  100  of  FIG. 1 , according to one embodiment. The computing device  700  is an exemplary device that is implementable for each of the components of the system  100 , including the stations  130 A- 130 N, the access points  130 A- 130 N, and the SDN controller  110 . The computing device  700  can be a mobile computing device, a laptop device, a smartphone, a tablet device, a phablet device, a video game console, a personal computing device, a stationary computing device, a server blade, an Internet appliance, a virtual computing device, a distributed computing device, a cloud-based computing device, or any appropriate processor-driven device. 
         [0050]    The computing device  700 , of the present embodiment, includes a memory  710 , a processor  720 , a storage device  730 , and an I/O port  740 . Each of the components is coupled for electronic communication via a bus  799 . Communication can be digital and/ or analog, and use any suitable protocol. 
         [0051]    The memory  710  further comprises network applications  712  and an operating system  714 . The network applications  712  can include the modules of SDN controllers or access points as illustrated in  FIGS. 2 and 3 . Other network applications  712  can include a web browser, a mobile application, an application that uses networking, a remote application executing locally, a network protocol application, a network management application, a network routing application, or the like. 
         [0052]    The operating system  714  can be one of the Microsoft Windows® family of operating systems (e.g., Windows 95, 98, Me, Windows NT, Windows 2000, Windows XP, Windows XP x64 Edition, Windows Vista, Windows CE, Windows Mobile, Windows 7 or Windows 8), Linux, HP-UX, UNIX, Sun OS, Solaris, Mac OS X, Alpha OS, AIX, IRIX32, or IRIX64. Other operating systems may be used. Microsoft Windows is a trademark of Microsoft Corporation. 
         [0053]    The processor  720  can be a network processor (e.g., optimized for IEEE 802.11), a general purpose processor, an application-specific integrated circuit (ASIC), a field programmable gate array (FPGA), a reduced instruction set controller (RISC) processor, an integrated circuit, or the like. Qualcomm Atheros, Broadcom Corporation, and Marvell Semiconductors manufacture processors that are optimized for IEEE 802.11 devices. The processor  720  can be single core, multiple core, or include more than one processing elements. The processor  720  can be disposed on silicon or any other suitable material. The processor  720  can receive and execute instructions and data stored in the memory  710  or the storage device  730   
         [0054]    The storage device  730  can be any non-volatile type of storage such as a magnetic disc, EEPROM, Flash, or the like. The storage device  730  stores code and data for applications. 
         [0055]    The I/O port  740  further comprises a user interface  742  and a network interface  744 . The user interface  742  can output to a display device and receive input from, for example, a keyboard. The network interface  744  (e.g. RF antennae) connects to a medium such as Ethernet or Wi-Fi for data input and output. 
         [0056]    Many of the functionalities described herein can be implemented with computer software, computer hardware, or a combination. 
         [0057]    Computer software products (e.g., non-transitory computer products storing source code) may be written in any of various suitable programming languages, such as C, C++, C#, Oracle® Java, JavaScript, PHP, Python, Perl, Ruby, AJAX, and Adobe® Flash®. The computer software product may be an independent application with data input and data display modules. Alternatively, the computer software products may be classes that are instantiated as distributed objects. The computer software products may also be component software such as Java Beans (from Sun Microsystems) or Enterprise Java Beans (EJB from Sun Microsystems). 
         [0058]    Furthermore, the computer that is running the previously mentioned computer software may be connected to a network and may interface to other computers using this network. The network may be on an intranet or the Internet, among others. The network may be a wired network (e.g., using copper), telephone network, packet network, an optical network (e.g., using optical fiber), or a wireless network, or any combination of these. For example, data and other information may be passed between the computer and components (or steps) of a system of the invention using a wireless network using a protocol such as Wi-Fi (IEEE standards 802.11, 802.11a, 802.11b, 802.11e, 802.11g, 802.11i, 802.11n, and 802.11ac, just to name a few examples). For example, signals from a computer may be transferred, at least in part, wirelessly to components or other computers. 
         [0059]    In an embodiment, with a Web browser executing on a computer workstation system, a user accesses a system on the World Wide Web (WWW) through a network such as the Internet. The Web browser is used to download web pages or other content in various formats including HTML, XML, text, PDF, and postscript, and may be used to upload information to other parts of the system. The Web browser may use uniform resource identifiers (URLs) to identify resources on the Web and hypertext transfer protocol (HTTP) in transferring files on the Web. 
         [0060]    This description of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form described, and many modifications and variations are possible in light of the teaching above. The embodiments were chosen and described in order to best explain the principles of the invention and its practical applications. This description will enable others skilled in the art to best utilize and practice the invention in various embodiments and with various modifications as are suited to a particular use. The scope of the invention is defined by the following claims.