Patent Publication Number: US-9413797-B2

Title: Data communication system and method

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 14/246,570, filed Apr. 7, 2014, which claims the benefit under 35 U.S.C. §119(a) and 37 CFR §1.55 to UK Patent Application No. 1307341.6, filed on Apr. 23, 2013, the entire disclosure of each of which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     The present disclosure relates to data communication systems, for example to data communication systems for communicating audio and video information between mutually different client devices; peer-to-peer and multipoint communication systems can be used with the present disclosure, as well as the present disclosure is suitable also for unicast, multicast and multi-unicast (XCAST) routing schemes. Moreover, the present disclosure is also concerned with methods of operating aforesaid data communication systems. Furthermore, the present disclosure is also concerned with software products recorded on machine-readable data storage media, wherein the software products are executable upon computing hardware for implementing aforesaid methods. 
     BACKGROUND INFORMATION 
     Communication systems employing data packet communication via a data communication network, for example the Internet, are well known. For example, Voice-over-Internet-Protocol (VoIP) has been known for many years and is employed in contemporary communication products such as Skype telephonic and video-conferencing services; “Skype” is a registered trademark. When a plurality of persons are employing VoIP and associated video conferencing products, it is found desirable that voice and video information are communicated without gross delay, otherwise maintaining a conversation or video conference becomes difficult for the participating persons. However, the Internet was conceived to be a data packet communicating network, wherein data packets can potentially take a multiplicity of routes within the Internet from a sending device to a receiving device. As a result, it is often difficult when using the Internet to ensure prompt delivery of a data packet from the sending device to the receiving device, resulting in potential latency being experienced by users. Aforementioned communication issues are addressed in a known document “Real-Time Messaging Protocol (RTMP) specification, Adobe Developer Connection”, URL: http://www.adobe.com/devnet/rtmp.html. 
     A problem encountered with known real-time communication systems, and associated methods employing communication networks such as the Internet, is that the methods do not adequately integrate video and audio codecs into their execution. Devices including such codecs are often mutually different in respect of their processing power, which affects their rate of processing received data and also generating data for transmission. Moreover, infrastructures employed for implementing, for example, the Internet can vary considerably for various individual client devices, for example depending upon a geographical location of the individual client devices. When executing audio conferencing and/or video conferencing between a plurality of parties, audio delays of merely a couple of seconds to words at an end of a sentence can potentially render the sentence potentially unintelligible to parties participating to the conferencing. 
     Thus, known real-time communication systems have to take into account properties of communication infrastructures, for example communication networks, employed to convey data packets; the infrastructures can vary considerably for various individual client devices. For example, it is desirable that audio information transmitted between parties, for example their client devices, is conveyed with a delay not exceeding a few ten&#39;s of milliseconds. Such delay of a few ten&#39;s of milliseconds is usually achievable, provided that video information is not concurrently also transmitted. In comparison to audio information pertaining to a given period of time, corresponding video information pertaining to the same given period of time results in generation of data which is typically at least an order of magnitude greater in size in comparison to that of the audio information; however, a ratio of size of audio data to corresponding video data will depend upon quality criteria pertaining to the video information and the audio information, for example video pixel field resolution and video frame update rate. 
     From the foregoing, it will be appreciated that known systems for communicating audio and video information between a plurality of parties, for example in a video conferencing situation, via a communication network such as the Internet, are not optimal in their manner of operation, especially when parties employ mutually different devices with associated mutually different data processing characteristics. 
     In this disclosure, acronyms and definitions are employed as provided in Table 1. 
     
       
         
           
               
             
               
                 TABLE 1 
               
             
            
               
                   
               
               
                 Acronyms and definitions 
               
            
           
           
               
               
               
            
               
                   
                 Abbreviation  
                   
               
               
                   
                 or acronym  
                 Definition 
               
               
                   
                   
               
               
                   
                 ACK 
                 This fundamental technique requires a receiver to 
               
               
                   
                   
                 respond with an acknowledgment message as it 
               
               
                   
                   
                 receives given data 
               
               
                   
                 CPU 
                 Central Processing Unit 
               
               
                   
                 Frame Rate 
                 “Frame frequency”, namely a frequency rate at 
               
               
                   
                   
                 which an imaging device produces unique 
               
               
                   
                   
                 consecutive images, referred to image “frames”; 
               
               
                   
                   
                 “frames” in this context are not to be confused with 
               
               
                   
                   
                 network packets. Moreover, there are also 
               
               
                   
                   
                 mentioned “audio frames” which include some 
               
               
                   
                   
                 predetermined sequence of audio sample data 
               
               
                   
                 MSS 
                 Maximum Segment Size of a communication 
               
               
                   
                   
                 protocol 
               
               
                   
                 MTU 
                 Maximum Transmission Unit of a communication 
               
               
                   
                   
                 protocol 
               
               
                   
                 NIC 
                 Network Interface Controller, namely “network 
               
               
                   
                   
                 interface card” 
               
               
                   
                 Packet Rate 
                 A frequency at which packets of data can be 
               
               
                   
                   
                 delivered via a network; in an event that packet 
               
               
                   
                   
                 receipt acknowledgements are needed, such 
               
               
                   
                   
                 frequency is generally decreased 
               
               
                   
                 RTMP 
                 Real-Time Messaging Protocol 
               
               
                   
                 TCP 
                 Transmission Control Protocol of Internet protocol 
               
               
                   
                   
                 suite 
               
               
                   
                 UDP 
                 User Datagram Protocol of Internet protocol suite 
               
               
                   
                 QoS 
                 Quality of service is an ability to provide different 
               
               
                   
                   
                 priorities to different applications, users, or data 
               
               
                   
                   
                 flows, or to guarantee a certain level of performance 
               
               
                   
                   
                 to a data flow 
               
               
                   
                 TX 
                 Data being transmitted 
               
               
                   
                 RX 
                 Data being received 
               
               
                   
                 time-critical 
                 A data which become useless in period of time after 
               
               
                   
                   
                 existence. 
               
               
                   
                   
               
            
           
         
       
     
     SUMMARY 
     The present invention seeks to provide an improved data communication system for providing enhanced quality-of-service for low-end client devices as well as high-end client devices, in respect of data processing capability, for example in an audio and video conferencing arrangement. 
     The present invention also seeks to provide an improved method of communicating data in a data communication system for providing enhanced quality-of-service for low-end client devices as well as high-end client devices, in respect of data processing capability, for example in an audio and video conferencing arrangement, but not limited thereto. 
     According to a first aspect, there is provided a data communication system including a plurality of communication devices coupled to each other via a communication network. The plurality of communication devices are operable to exchange data therebetween, wherein the system is operable to allocate the data into a primary type of data and at least a secondary type of data. The primary type of data is communicated substantially immediately within the system, and at least the secondary type of data is communicated in the system in association with corresponding acknowledgements (ACK) being communicated in the system in response to receipt and processing of the at least secondary type of data at one or more of the plurality of communication devices. 
     The invention is of advantage in that it is capable of providing an improved quality-of-service to the client devices, for example when the client devices and their associated communication links to the data server arrangement are of mutually different data communication performance. 
     It will be appreciated that the centralized server can be used for communicating data, or data can be communicated in a peer-to-peer manner. The communication can be between clients or between server and client, for example when playback is used. 
     It is possible that another server can exchange data between a client device and the centralized server as a router, if a direct client connection to the centralized server is slower than the connection between client to a route server and the centralized server. The route server can exists in any location or network, which has better response time than centralized server for the client, and it can also control the data flow of different data types. When there are many clients in the communication, the centralized server is typically then needed or some client should then operate as the centralized server. If the communication is only between two devices, peer-to-peer communication is also optionally employed. Peer-to-peer communication can also be used with multipoint communication, for example peer-to-peer rings, wherein the clients are mutually connected by using structured overlay network using ring topology. This kind of peer-to-peer communication can sometimes start with the centralized server, but there is no active need to use a centralized server during the communication. The clients can execute acknowledgements by themselves and make change requests by themselves, when they notice that there is need to change some properties, for example resolution, frame-rate, audio quality, and so forth. In multipart communication, there is often a benefit in using a centralized server, because the centralized server can do all needed controls and adjustments, but it is not mandatory. 
     Optionally, in the data communication system, the primary type of data includes audio data, and the secondary type of data includes image and/or video data and/or any other data. 
     Optionally, the data communication system can be a video conferencing service, a video broadcasting service (such as Youtube, Netflix, Viaplay and similar), a teleconference service, a multiuser game service, a video-on-demand service and so forth. 
     Optionally, the data communication system is operable to determine communication characteristics of the communication network arrangement and/or of one or more of the client devices, and to adjust one or more rates of data packet communication to the one or more client devices as a function of the determined communication characteristics. Beneficially, a client measures the remote end network and CPU congestion by the interval of the ACKs received. Moreover, a client measures the local computational effort by receiving buffer buildup, CPU load and/or video/audio rendering interval. Furthermore, a client adjusts the outbound data quantity and local use of CPU resources by quality and/or frame rate. The system is able, because of the significant acknowledgements of the second or later priority data, to adapt itself constantly for fluctuating sub-network speeds and heavy processing loads. That is, not even an attempt is made to code a new burst of video stream until the receiver has acknowledged the correct decoding of the previous, or the one before the previous burst of video stream. 
     Namely, in general the fastest operation is achieved by having one extra buffer so that the new frame is transmitted always when the next to the previous frame has been acknowledged. Using this extra buffer makes it possible to always have one frame under process (or completed for the next stage), in all phases of the entire process chain, namely in the encoding stage, in the transmission stage, in the reception stage and in the decoding stage. In the setup using an extra buffer, the encoder transmits the first two frames fast, and then waits for the acknowledgement of the first frame before transmitting the third frame and so forth. Such a setup increases the frame rate nicely, yet does not block the system, or cause large delays. That is, the encoder does not need to wait for the acknowledgement by the decoder for the first frame before encoding and delivering the second frame. The acknowledgement by the decoder for the first frame is however needed before the encoder will encode and deliver the third frame, et cetera. The ‘extra buffer’ mentioned here can reside in the decoder, in the encoder or possibly in a proxy server. 
     Optionally, in respect of determined communication characteristics, an adjustment is implemented by a client measuring a remote end network and CPU congestion by a temporal interval for acknowledgements (ACKs) to be received and/or by a client measuring a local computational effort expended in respect of a receiving buffer buildup, CPU load and/or video/audio rendering interval and/or by a client adjusting an outbound data quantity and local use of CPU resources by quality and/or frame rate. 
     Optionally, the data communication system is operable to determine communication characteristics of the communication network arrangement and/or of one or more of the plurality of communication devices, and to adjust one or more rates of data packet communication to the one or more of the plurality of communication devices as a function of the determined communication characteristics. 
     Optionally, the data communication system is operable to determine communication characteristics of the communication network arrangement and/or of one or more of the plurality of communication devices, and to adjust a maximum segment size (MSS) of data packet communication to the one or more of the plurality of communication devices as a function of the determined communication characteristics. 
     Optionally, in the data communication system, at least one of the plurality of communication devices is at least one of a wireless-enabled mobile communication device and a wirelessly-connected personal computer (PC). 
     Optionally, the data communication system is operable to communicate at least tertiary data in a non-time-critical manner between the plurality of communication devices, wherein the at least tertiary data corresponds to at least one of documents, measurement data. 
     Optionally, the data communication system is operable to communicate in a manner such that the primary type of data communicated to a first communication device functioning as a server is substantially immediately retransmitted therefrom to one or more second communication devices among the plurality of communication devices. 
     Optionally, the data communication system is operable to communicate the primary type of data as a highest priority followed by the secondary data as a lower priority. 
     Optionally, the data communication system is operable on a momentary basis to prioritize the secondary or the tertiary type of data over the primary type of data when communicating to the plurality of communication devices. Optionally, in the data communication system, the communication network arrangement is implemented, at least in part, as a peer-to-peer communication network. 
     Optionally, in the data communication system, the plurality of communication devices are further operable to communicate with each other using a peer-to-peer mode within the peer-to-peer communication network. 
     Optionally, the data communication system includes a centralized server coupled to the communication network. 
     Optionally, in the data communication system, the primary type of data and the secondary type of data are not communicated to the centralized server when two or more communication devices communicate in the peer-to-peer mode. 
     Optionally, in the data communication system, the two or more communication devices operate in the peer-to-peer mode when the primary type of data and the secondary type of data are used only by a single user. 
     Optionally, in the data communication system, a peer-to-peer connection between two or more communication devices is constructed using a TCP/IP protocol stack, using at least one of a UPnP technology and a TCP Hole Punching technique. 
     Optionally, in the data communication system, the communication network arrangement is implemented, at least in part, via the Internet implementing TCP/IP, or UDP/IP. 
     Optionally, in the data communication system, the centralized server inspects one or more capabilities of one or more of the communication devices and selects at least one communication device to function as a server for other communication devices. 
     Optionally, in the data communication system, the centralized server arrangement is operable to host a service or services, wherein the one or more services includes a virtual room, a multipoint server and/or a multiplayer server, such that the system is operable to provide at least one of: a video conferencing service, a video broadcasting service, a teleconference service, a multiuser game service, and a video-on-demand service to parties using at least one of the plurality of communication devices. 
     Optionally, a control command is determined to have a higher priority than one of audio data and video data. 
     Optionally, the control command is determined to be the primary type of data and one of audio data and video data is determined to be the secondary type of data. 
     According to a second aspect, there is provided a method of communicating data in a data communication system including a plurality of communication devices coupled via a communication network. The method includes:
     (a) operating the plurality of communication devices to exchange data therebetween, wherein the system is operable to allocate the data into a primary type of data and at least a secondary type of data; and   (b) communicating the primary type of data substantially immediately within the system, and communicating at least the secondary type of data in the system in association with corresponding acknowledgements (ACK) being communicated in the system in response to receipt and processing of the at least secondary type of data at one or more of the plurality of communication devices.   

     Optionally, the method includes arranging for the primary type of data to include audio data, and for the secondary type of data to include image and/or video data and/or any other data. 
     Optionally, the method is used in data communication systems such as video conferencing services, video broadcasting services (Youtube, Netflix, Viaplay and similar), teleconference services, multiuser game services, video-on-demand services. 
     Optionally, the method includes operating the system to determine communication characteristics of the communication network arrangement and/or of one or more of the plurality of communication devices, and to adjust one or more rates of data packet communication to the one or more of the plurality of communication devices as a function of the determined communication characteristics. 
     Optionally, the method includes operating the system to determine communication characteristics of the communication network arrangement and/or of one or more of the plurality of communication devices, and to adjust a maximum segment size (MSS) of data packet communication to the one or more of the plurality of communication devices as a function of the determined communication characteristics. 
     Optionally, the method includes enabling at least one of the one or more communication devices being at least one of a wireless-enabled mobile communication device and a wirelessly-connected personal computer (PC). 
     Optionally, the method includes operating the system to communicate at least tertiary data in a non-time-critical manner between the plurality of communication devices, wherein the at least tertiary data corresponds to at least one of: documents, measurement data. 
     Optionally, the method includes operating the system to communicate in a manner such that the primary type of data communicated to a first communication device among the plurality of communication devices is substantially immediately retransmitted therefrom to one or more second communication devices among the plurality of communication devices. 
     Optionally, the method includes operating the system to communicate the primary type of data as a highest priority followed by the secondary data as a lower priority. 
     Optionally, the method includes operating the system on a momentary basis to prioritize the secondary or the tertiary type of data over the primary type of data when communicating to the communication devices. 
     Optionally, the method includes implementing the communication network arrangement, at least in part, as a peer-to-peer communication network. 
     Optionally, the method further includes the operating the system enabling the plurality of communication devices to communicate with each other in a peer-to-peer mode within the peer-to-peer communication network. 
     Optionally, the method further includes operating the system in such a manner that the primary type of data and the secondary type of data are not communicated to a centralized server when two or more communication devices communicate in the peer-to-peer mode. 
     Optionally, the method further includes operating the system in such a manner that the two or more communication devices communicate in the peer-to-peer mode when the primary type of data and the secondary type of data are used only by a single user. 
     Optionally, the method further includes constructing a peer-to-peer connection between communication devices using a TCP/IP protocol stack, using at least one of a UPnP technology and a TCP Hole Punching technique. 
     Optionally, the data communication system further includes a centralized server coupled to the plurality of communication devices via the communication network arrangement, and the method further includes inspecting, by the centralized server, one or more capabilities of one or more of the communication devices and selecting, by the centralized server, at least one communication device to function as a server for other communication devices. 
     Optionally, the method includes implementing the communication network arrangement, at least in part, via the Internet implementing TCP/IP or UDP/IP. 
     Optionally, the method includes operating the data server arrangement to host one or more services, wherein the one or more services comprises a virtual room, a multipoint server and/or a multiplayer server, such that the system is operable to provide at least one of a video conferencing service, a video broadcasting service, a teleconference service, a multi-user game service, and a video-on-demand service to parties using the at least one of the plurality of communication devices. 
     According to a third aspect, there is provided a computer program product including a non-transitory computer readable storage medium having computer readable instructions stored thereon. The computer readable instructions are executable by a computerized device including a processor to implement the method pursuant to the second aspect. 
     Optionally, the method includes determining a control command to have a higher priority than one of audio data and video data. 
     Optionally, the method includes determining the control command to be the primary type of data and determining one of audio data and video data to be the secondary type of data. 
     It will be appreciated that features of the invention are susceptible to being combined in various combinations without departing from the scope of the invention as defined by the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Embodiments of the present invention will now be described, by way of example only, with reference to the following drawings wherein: 
         FIG. 1  is an illustration of a data communication system, known as a “Starwindow® Service”, employing a centralized configuration of data server for serving a plurality of mutually different client devices A, B, X; “Starwindow” is a registered trademark of Gurulogic Microsystems Oy; 
         FIG. 2  is an illustration of data exchanges between two client devices A and B via a centralized data server communicating through firewalls, and subsequently circumventing the centralized data server to reducing computer load thereupon; and 
         FIG. 3  is an illustration of thread execution associated with processes implemented in the data communication system of  FIG. 1 . 
     
    
    
     In the accompanying drawings, an underlined number is employed to represent an item over which the underlined number is positioned or an item to which the underlined number is adjacent. A non-underlined number relates to an item identified by a line linking the non-underlined number to the item. When a number is non-underlined and accompanied by an associated arrow, the non-underlined number is used to identify a general item at which the arrow is pointing. 
     DETAILED DESCRIPTION 
     In overview, in this disclosure, there is described a data communication system which is operable to address quality-of-service (QoS) for low-end clients as well as high-end clients to a same real-time communication session without congesting a low-end communication network whilst not blocking a low-end CPU with too much data in too short a time. The data communication system addresses the aforesaid quality-of-service (QoS) by dividing data to be transmitted in the data communication system into a plurality of types of data, for example primary and secondary types of data, and by managing delivery of such types of data to clients in a centralized manner, for example by employing a primary method and a secondary method. Beneficially, there is employed optimized network usage, wherein Relative Packet Rates are selected appropriately, and a tailor-made acknowledgement scheme is employed in the data communication system. Embodiments described herein are devised, for example, in relation to providing a video conference solution, namely for ensuring a quality-of-service (QoS) for all sorts of client devices and network types. For example, such a video conferencing solution is susceptible to being implemented via data communication networks, for example the Internet but not limited thereto, wherein regions of the communication networks can mutually differently vary in communication performance, and devices coupled together via such data communication networks for providing the video conferencing solution can mutually vary in respect of their capability of processing data received thereat. 
     The video conferencing solution is beneficially implemented pursuant to a Starwindow concept, wherein two or more parties are communicatively mutually coupled together via a virtual room that is situated at a service provider&#39;s server; all information passing through the server is transmitted to all the parties coupled to the server. However, it will be appreciated that, sometimes, clients can also operate as server or server nodes and then the real centralized server is not always needed. In playback, it is feasible that there is only one client and server that holds and delivers information. Sometimes, the playback service is operating similarly as one sending client and it can create its own real time issues similarly as client. This means that there can arise a need to adjust an amount of data delivery, in client or in server, based on properties of receiving clients; for example, such a situation arises when there are multiple clients receiving the playback simultaneously, when they are to discuss the playback. A recording service can also sometimes be understood as a receiving client. Ideally, the recording service stores the delivered information using the quality that it receives; sometimes transcoding might be needed, because some clients might have a slower network or terminal device than others. In such a case, the delivered information might be recoded with lower quality to achieve better compression ratio, or optionally transcoded with another codec, if the client device/application is not compatible with the codec used in the delivered data, or if the optional codec would yield other benefits (e.g. encoding support, encoding speed enhancement, savings on memory usage, processing load and time and/or energy consumption during encoding, decoding support, decoding speed enhancement, savings on memory, processing load and time and/or energy consumption during decoding, reduced amount of encoded data, increased quality of decoded data). 
     The recoded/transcoded content coded with lower quality will have a smaller data size and consequently needs less bandwidth to transmit and less storage space on hard drives. However, the recoding/transcoding process consumes processing time and energy at the server, and a lower quality cannot be used if lossless quality is required, so the cost-benefit ratio must be computed in each case individually. 
     The aforesaid Starwindow concept is capable of addressing a problem which is encountered in practice arising from differences in communication network speed and also a problem arising from differences in processing power of client devices of the parties, as well as a problem arising mutually different network infrastructures through which the client devices of the parties are communicatively coupled to the server. 
     Embodiments, as will be herewith described, are beneficially implemented via the Internet, but optionally employ wireless communication networks as well as optical fibre and wire connection networks. When the contemporary Internet is employed, the Internet beneficially employs Hypertext Transfer Protocol (HTTP). The Protocol is an application protocol for distributed, collaborative hypermedia information systems. In implementation, HTTP is a multi-linear set of objects which are operable to build a network using logical links to define the network; the links are often referred to as being “hyperlinks” which define a network relationship between nodes. 
     HTTP is designed to permit immediate network elements to enable communications between client devices and servers. High-traffic web-sites of the Internet often employ web cache servers that are operable to deliver content on behalf of upstream servers to improve response times for data and/or service delivery. Moreover, HTTP proxy servers at private network boundaries are beneficially used to facilitate communication for clients without a globally routable Internet address, namely by relaying messages via external servers. 
     HTTP resources are identified and located on a given network by using Uniform Resource Identifiers (URI&#39;s), also referred to as Uniform Resource Locators (URL&#39;s). Moreover, URI&#39;s and hyperlinks are expressed in Hypertext Markup Language (HTML) which are capable of forming webs of mutually interlinked hypertext documents. 
     HTTP defines a method, conveniently referred to as “verbs”, for indicating a desired action to be performed in respect of an identified resource. The resource is, for example, a data file or an output from an executable object residing on one or more servers. Examples of HTTP “verbs” are provided in Table 2. 
     
       
         
           
               
             
               
                 TABLE 2 
               
             
            
               
                   
               
               
                 HTTP “verbs” 
               
            
           
           
               
               
            
               
                 “Verb” 
                 Details 
               
               
                   
               
               
                 GET 
                 Requests a representation of a specified resource, wherein 
               
               
                   
                 requests using “GET” should only retrieve data 
               
               
                 HEAD 
                 Requests a response which is identical to that obtainable  
               
               
                   
                 from GET, but devoid of any response body; “HEAD” is  
               
               
                   
                 often employed for retrieving meta-data in an efficient  
               
               
                   
                 manner 
               
               
                 POST 
                 Requests that a given server accepts an entity enclosed in  
               
               
                   
                 the request as a new sub-ordinate of a given web resource  
               
               
                   
                 identified by a URL 
               
               
                 PUT 
                 Requests that an enclosed entity be stored in respect of a 
               
               
                   
                 supplied URI (URL). If the URI refers to an already  
               
               
                   
                 existing resource, that resource is modified. 
               
               
                 DELETE 
                 Requests deletion of a specified resource 
               
               
                 TRACE 
                 Results in a received request to be echoed back to the  
               
               
                   
                 given client 
               
               
                 OPTIONS 
                 Returns HTTP methods supported by a server associated  
               
               
                   
                 with a given URL 
               
               
                 CONNECT 
                 Converts a requested connection to a transparent TCP/ 
               
               
                   
                 IP tunnel, for example for facilitating SSL-encrypted  
               
               
                   
                 communication (HTTPs) through an unencrypted HTTP  
               
               
                   
                 proxy as aforementioned 
               
               
                 PATCH 
                 Requests application of partial modifications to a given  
               
               
                   
                 resource 
               
               
                   
               
            
           
         
       
     
     In embodiments described in this disclosure, there are employed a plurality of methods, for example primary and secondary methods, for processing data at a centralized server communicatively coupled to a plurality of client devices of parties; the centralized server is beneficially coupled in a Starwindow or similar service configuration. For example, in the primary method, the client devices of the parties are connected via a same predetermined TCP/UDP port at the centralized server; such a manner of connection creates a connection session for all the parties involved. Beneficially, this session lasts for as long as a given party is communicatively connected with the aforesaid virtual room. Moreover, it will be appreciated that User Datagram Protocol (UDP) is connectionless, such that a given communication session is controlled at a software application level when User Datagram Protocol (UDP) is employed. 
     Software applications, executing upon computing hardware for implementing embodiments of the disclosure, employ the aforesaid plurality of methods, for example primary and secondary methods, for mutually communicating by transmitting primary data and secondary data. The primary data includes, for example, audio data that is time-critical. Moreover, the secondary data includes, for example, video data which is often less time-critical or non-time-critical. 
     In operation of the aforesaid Starwindow or similar service configuration, primary data including audio data is transmitted to a centralized server that substantially immediately retransmits the primary data to client devices of designated parties to a given session, independently of communication or command protocol employed; thus, the primary data as time-critical audio data is never acknowledged in the Starwindow or similar service and a given recipient client device is never made to wait to receive the retransmitted primary data, and the secondary data as less time-critical video data is transmitted via the Starwindow or similar service without blocking or flooding network connections or any CPU of recipient devices of the parties to the session, because it is controlled by acknowledgements. Beneficially, the acknowledgements can delay sending/transmission of the next packet, and from the delay there can be deduced how well the data has been communicated and/or how much time it takes to process the data in order to make a decision as to whether or not the amount of data should be decreased, for example by lowering the quality or reducing the size of the image. With the help of acknowledgements, both data transmission and data processing can be monitored, and based on these observations, image quality or size (which also often influences the quality) can be altered. 
     The aforesaid secondary data is transmitted by a given client device of a party to the session to be received at the centralized server; the centralized server retransmits to other parties of the given session which send acknowledgements to confirm receipt and processing of the retransmitted secondary data. By controlling such flow of the secondary data, the Starwindow or similar service is capable of avoiding congesting low-end networks, which may have limited data bandwidth, and blocking low-end CPU&#39;s with too much data in too short a time. In contradistinction, many known contemporary protocols intended for real-time communication often work only in session between two mutual participants; when more participants join a given session, data processing required becomes too demanding for the participants regarding CPU&#39;s of their client devices as well as for network infrastructures conveying data flows associated with the given session. Embodiments as herewith described in this disclosure, for example implemented as a Starwindow service, avoid causing excess demands on CPU&#39;s of client devices by controlling data to be retransmitted in such a way that client devices of parties which have weaker capacity to process data received thereat remain in session. 
     In an example where control commands enable a real-time functionality of a software program of the data communication system, the control commands are considered more important than audio data and, therefore, are given a relatively higher priority. In another example, audio data for a teleconference is given a higher priority over video data, as a time-to-live of the audio data is only a few tenths of a second. A high prioritization of the audio data is desirable to reduce delays that could otherwise render the audio unintelligible, for example, when undertaken as an oral dialogue. In yet another example, in a real-time control system, real-time sensor data is given a higher priority over archive data. In still another example, test data that is of more interest to a given receiver is given a higher priority over extraneous advertisement content. 
     Optionally, when assigning the prioritization codes, a lowest prioritization code is assigned to a type of data that has a highest priority. In this regard, the prioritization codes can be implemented, for example, as defined in an example table below. 
     
       
         
           
               
               
               
             
               
                   
                   
               
               
                   
                 Prioritization code 
                 Information type 
               
               
                   
                   
               
             
            
               
                   
                 0x00 
                 Reserved 0 
               
               
                   
                 0x01 
                 Control command 
               
               
                   
                 0x02 
                 Broadcast message 
               
               
                   
                 0x04 
                 Audio data 
               
               
                   
                 0x08 
                 Video data 
               
               
                   
                 0x10 
                 Reserved 5 
               
               
                   
                 0x20 
                 Text data 
               
               
                   
                 0x40 
                 File data 
               
               
                   
                 0x80 
                 Playback data 
               
               
                   
                   
               
            
           
         
       
     
     In the example table above, control commands are more important than broadcast messages, which are more important than audio data, which is more important than video data. This implies that even when there would be video data available to be transmitted, control commands, broadcast messages and audio data will be transmitted before the video data. 
     It should be appreciated that the table above, containing prioritization codes, is only one example of embodiments of the disclosure and should not be considered in any way as limiting the priorities to only the order described in the example table. 
     Embodiments of the disclosure will now be described with reference to  FIG. 1 . A data communication system is indicated generally by  10 . The system  10  includes a server  20 , for example implemented as a Starwindow Service, provided with an identification “Room 8001”. Client devices  30  compatible with the server  20 , for example Starwindow-compatible client devices, include client devices A, B and X; these client devices  30  are able to connect to a predetermined virtual room, for example the aforementioned “Room 8001” implemented via a TCP port 8001 of the server  20 . Optionally, connections to the predetermined virtual room are implemented as connectionless User Datagram Protocol (UDP) sessions, wherein identification and addressing are port independent; for example, identification and addressing are optionally implemented at a socket level or by another form of arbitration, for example by use of an application level command. Beneficially, this virtual room exists permanently, or it is a creation of a given communication session using the system  10 . The virtual room creates an environment for a plurality of parties to communicate mutually, wherein the Starwindow Service or similar is operable to transmit audiovisual data of all mutually connected parties of the session in a controlled manner. 
     The system  10  of  FIG. 1  is operable to transmit data to the client devices  30 , taking into account their CPU performances for processing data, and also their associated communication network infrastructures and their associated performance characteristics, for example data communication capacity and/or latency performance. Optionally, the system  10  employs several network protocols and audio-visual (AV) codecs. However, an important feature of operation of the system  10  is that the server  20  manages in a centralized manner primary and secondary data flows between the server  20  and the client devices  30 , while taking into account data processing resources available at the client devices  30 . In  FIG. 1 , “TX” denotes data being transmitted, and “RX” denotes data being received, from a point of view of client devices  30 . The client devices  30  create at least two connections, or one two-dimensional RX/TX-connection as shown for X-client, to the server  20 , namely the Starwindow service or similar, namely at least one connection for receiving data and at least one connection for transmitting data. Optionally, it is feasible to employ separate connections for video information and audio information. 
     The system  10  of  FIG. 1  is operable to transmit data through one or more route servers. Usually, the route server exists in a backbone network, but it may optionally exist in any network. Moreover, a client may operate as a route server. Normally, the route server network capacity is greater than the network to which a client is connected. Thus, it is possible that another server can exchange data between a given client device and a centralized server as a router if direct client connection to centralized server is slower than the connection between the client to a route server and the centralized server. Therefore, if a route server is used, then it usually exists in better geolocation than centralized server for the client network. The route server optionally also controls the data flow of different data types, as in the aforesaid described method of QoS. The acknowledgements related to secondary data take care of the network capacity variation with or without router servers. The speed is always limited by the slowest part of the network, and therefore it is usually not so crucial regarding whether or not the route server used for the network is faster or slower in different sides of the route server. If the route server has capacity to adjust the data, then it can also optionally execute data adjustments. 
     It is beneficial to utilize a communication network for coupling the client devices  30  to the server  20 , wherein the system  10  is operable to utilize the communication network in an optimal manner. In operation, the server  20  requests a Maximum Transmission Unit (MTU) value from each of the client devices  30  in order to determine a maximum data packet size that the client devices  30  are each able to handle, for example to process in their CPU&#39;s. Optionally, for increasing a speed of transmission within the system  10 , communication networks of the system  10  employ User Datagram Protocol (UDP) peer-to-peer and optimized packet headers, for example for enabling peer-to-peer communication to occur directly between the client devices  30 , for example without a need for acknowledgements for every data packet that the Transmission Control Protocol (TCP) requires. 
     Namely, when no benefits can be gained by transmitting the data in a centralized way, for example because there are no multiple users for the same data or transcoding is not needed, then it is beneficial to transmit the data directly between the client devices, without circulating it via a centralized server. Furthermore, the peer-to-peer mode enables a local group to communicate directly inside a network, without a need to send data back and forth to a server which is possibly situated at a remote location. It should be appreciated that sometimes a client is capable of acting as a server. However, the ultimate control should be kept with the centralized server. 
     The primary embodiment pursuant to the disclosure is via a centralized server: 
     &lt;client&gt; - - - &lt;server&gt; - - - &lt;client&gt; 
     However, the centralized server setup is often not optimal, and if possible, a peer-to-peer connection is constructed using the TCP/IP protocol stack, primarily using the UPnP technology and secondarily TCP Hole Punching technique, in which cases the centralized server is bypassed as follows: 
     &lt;client&gt; - - - &lt;client&gt; 
     in such a way that one of the clients is made to act as a server for other clients: 
     &lt;client&gt; - - - &lt;client+server 
     Here, the concept ‘client+server’ is simply a client which acts as a server, i.e. its connection port is set to listen mode when the protocol in use is TCP over IP. Prior to engaging in peer-to-peer communication, the centralized server inspects the capabilities of the clients for selecting suitable candidates for the &lt;client+server&gt; role. It is to be noted that even here the role set for a client depends on the application that implements the invented method, e.g. the host of a Starwindow ‘room’ acts as a ‘client+server’. 
     It will be appreciated that for the embodiments pursuant to the disclosure use of TCP/IP is optional. Optionally, alternatively, UDP protocol can be used. TCP/IP is ideal for the acknowledgements but such a functionality can be simulated also when UDP is used. 
     Summarizing the foregoing, the system  10  handles data via the server  20  as at least primary and secondary types of data. Moreover, a communication network employed to couple the client devices  30  to the server  20  is optimized, and acknowledgements are handled in the system  10  is a customized manner. Thus, the system pursuant to the disclosure is not dependent on the regular acknowledgements of the protocol used, but instead, acknowledgements are generated as desired. Such features will be further elucidated in embodiments which will be described next. 
     Data packets communicated within the system  10  result in data flowing via the server  20 , wherein the flow of data is controlled by way of primary and secondary types of data being handled. Thus, in practical communication within the system  10 , at least two types of data are distinguished and processed. Beneficially, the primary type of data is often time-critical audio data which becomes outdated and must be communicated promptly before it becomes obsolete, especially when real-time communication applications are being executed within the system  10 . For example, it is found in practice that delaying last two words of a sentence by merely two seconds often renders the sentence intelligible, namely too late for comprehension to be achieved. 
     The secondary type of data, communicated within the system  10 , is not as time-critical as the aforesaid primary type of data, but nevertheless is beneficially transmitted, when possible, within the system  10  with a delay which does not adversely influence its intelligibility. The server  20  provides its service, for example Starwindow service, by controlling communication concerning transmission of the primary and secondary types of data, wherein the primary type of data for each client device  30  is transmitted via the server  20  without delay, or with minimal delay, such that the primary type of data is transmitted before the secondary type of data, even though the secondary type data, in an absence of such prioritization of the primary type of data, would have arrived earlier. It will be appreciated that it is possible for some part of the received secondary data never to be transmitted from server to one or more clients, for example, in a situation where a new image frame has arrived and the old image frame has not started to transmit yet to some clients. If a codec employed is able to skip the older frame, then it will be skipped to those one or more clients. The primary type of data, for example audio data, does not cause a deviating workload to the communication network or CPU of the client devices  30 , because the system  10  is operable such that primary type of data is not processed if it has become temporally obsolete, or obsolete for any other reason. Conversely, the secondary type of data is processed in a substantially similar manner to the primary type of data, except that the new secondary type of data is not transmitted within the system  10 , unless the old secondary data has been received and processed by one or more of the client devices  30  and one or more corresponding acknowledgements (ACK) have been sent by the one or more client devices  30  back to the server  20 . The acknowledgement (ACK) sent by one or more of the client devices  30  in response to receipt and processing of the secondary type of data thereat is technically beneficially executed using an ACK message pertaining to TCP/IP protocols, for example as defined in RFC 793 “Transmission Control Protocol”, URL: http://tools.ietf.org/html/rfc793 hereby incorporated by reference, in RFC791, URL: http://datatracker.ietf.org/doc/rfc791/ hereby incorporated by reference, and in “Internet Protocol”, URL: http://en.wikipedia.org/wiki/Internet_Protocol hereby incorporated by reference. This ACK message is beneficially transmitted in the header of TCP data packets; thus, the ACK message is beneficially communicated in such headers, because acknowledging received data packets is beneficially executed by a network card (NIC) of the one or more client devices  30  at hardware level, thereby avoiding a need to employ main CPU resources of the one or more client devices  30  for such acknowledgement purpose. There is optionally employed one or more alternative acknowledgement techniques without utilizing aforesaid ACK acknowledgement of a received TCP data packet, for example using a customized acknowledgement arrangement. 
     As regards handling acknowledgements in customized manner for secondary data, especially in the case where the UDP protocol is utilized, alternative ways of performing acknowledgements can be applied. For example, although the UDP protocol by default does not use acknowledgements, depending on the properties of current data in the stream, customized acknowledgements could be sent e.g. for each packet, or for every fifth packet, or a few times for each image, or for each image, or for every fifth image etc. 
     Congestion management of acknowledgement (ACK) messages from the one or more client devices  30  is implemented in the server  20 , and optionally also at the one or more client devices  30 . Moreover, the management is beneficially implemented in separate data packets communicated within the system  10 . Such congestion management enables the system  10  to control CPU and network resources on a per client device  30  basis. 
     With reference to functionality of service provided within the system  10 , it is beneficial that an acknowledgement of received secondary type of data be transmitted from a recipient as soon as a corresponding secondary data packet has been received and processed, because such prompt acknowledgement enables the communication network employed, and CPU load, to be most effectively managed. 
     The system  10  is thus capable of delivering a communication service, for example the aforementioned Starwindow service, which is operable to prevent the client devices  30  from congesting the communication network and from transmitting too much secondary type of data that would potentially congest the communication network serving weaker, less resourceful client devices  30 , for example whose reception speed might be permanently weaker. Moreover, the system  10  is capable of coping with varying data communication capacity of the communication network, for example arising from changing operating characteristics of Universal Serial Bus (USB) modems or USB network sticks, for example via wireless communication links. Furthermore, the system  10  is also beneficially managed to save transmission time for primary type of data, wherein primary data packets are beneficially always transmitted before secondary data packets. If there is space in the data packet that contains primary data, then that space is beneficially optionally also filled by secondary data; by employing such efficient use of packet data carrying capacity, a new primary data packet can be delivered immediately after this packet, but acknowledgement of that packet has to be received before the new secondary data packet can be transmitted. 
     In an example embodiment of the system  10 , a primary audio data packet is beneficially played back in real-time. Conversely, video data, which is usually ten times more voluminous and comprising several data packets, results in considerably more CPU load and thus causes an immediate lengthening of response time, also for the primary data packets, for example audio data. For this reason, as aforementioned, the secondary data packets are acknowledged by using an acknowledgement scheme, for example as described in the foregoing in respect of the Starwindow service. 
     In the service provided by the system  10 , for example the Starwindow service, several of the client devices  30  are equipped with low-end CPU&#39;s, but nevertheless are provided with a fast enough network connection to the server  20  and have joined a Starwindow virtual room, wherein the secondary image data is discarded and acknowledged as processed already at reception of the secondary data, in which case the CPU load is saved for processing primary data received at the client devices  30  with low-end CPU&#39;s. Moreover, the service is also capable of lessening the CPU load or save communication network capacity of the client devices  30  with low-end CPU&#39;s, namely weaker client devices  30 , by temporally delaying the acknowledgements of relatively faster client devices  30 , in which case the system  10  is operable to decrease an image frequency as provided in the secondary data. Furthermore, the system  10  is optionally operable, by controlling the server  20 , to define a video resolution of the virtual room hosted by the server  20 , in which case the client devices  30  transmit a smaller image, for example lower-resolution image or a more specific image (for example, just participant faces without background boarder), which results in a decrease in CPU load of weaker client devices  30  and corresponding associated communication network load. Optionally, the system  10  is operable to transcode the audio information of the primary type of data, and/or to decrease image update frequency and/or image resolution. Such adjustment in operation of the system  10  enables the weaker client devices  30  to cope with both primary and secondary types of data flow within the system  10 . 
     Beneficially, the client devices  30  receive and send information within the system  10  at a highest feasible resolution and quality, within limits of CPU and communication network resources to provide an optimal information transfer experience for parties using the client devices  30 . The client devices  30  optionally include one or more of: smart phones, tablet computers, phablet computers, lap-top computers, personal computers (PC&#39;s), personal data assistants (PDA&#39;s), wireless-enabled wrist-worn computers, but not limited thereto. 
     A most efficient manner, in the system  10 , of decreasing the CPU load of the weaker client devices  30  is achieved by decreasing their own audio and image encoding, for example by lowering quality, by lowering frame rate or by moving computational load to server by using less space-efficient encoding and allowing the server to compress the data more. Such an approach for assisting the weaker client devices  30  has a much bigger effect than decreasing decoding of the received data at weaker client devices  30 ; such adjustment is achievable in the system  10  on account of its ability to inspect speeds of data transmission to and/or from the client devices  30  in a centralized manner, both by using the aforesaid acknowledgement scheme and altering characteristics of requested and transmitted data. 
     In an event that the system  10  is instructed to communicate other types of data between the client devices  30 , for example files that do not have any real-time effects such as documents, measurement result data, the other types of data is beneficially communicated within the system  10  as a tertiary type of data having a priority lower than that of the primary and secondary types of data. Thus, within the system  10 , there are beneficially more than two prioritization levels employed in operation for data types communicated therethrough. However, such prioritization is beneficially implemented in the system  10  in a manner which is dynamically variable, such that on occasional moments, the prioritization is changed, for example document data is, for a fewer seconds, prioritized higher than audio and/or video data, whilst the document data is being distributed to the client devices  30 , for example during negotiations undertaken between the parties using the client devices  30 . Playback data can be understood as data that does not have real-time effects, or as data that contains primary and secondary data. Sometimes, when there are multiple parties that want simultaneously to watch the playback and discuss the playback, the playback can have the highest priority and the primary data and secondary data of the normal communication has lower priority than the playback. When one user is alone without other persons watching playback, then there can be only one receiving client and one client or server delivering the playback. In such a situation, the playback data contains typically primary and secondary data and these data are handled similarly as the data that is coming from other clients is coupled in communication. When a given recording has been made, the recording device, for example some client in the communication, a separate receiving client, a server node, a router server or server, can have bandwidth and processing resource restrictions. The recording device should affect the incoming data similarly as the request related to normal receiving clients using primary and secondary data and needed quality adjustments that may depend on bandwidth or processing capacity. 
     In the system  10 , it is most normal in operation that audio data is given a highest priority, as described in the foregoing, and video data is given a secondary priority, and other types of data given a tertiary or lower priority. Beneficially, there is employed in the system  10  percentage goals for shares of transmission of different data types, optionally such that long delays associated with data transmission within the system  10  are prevented. In an event that the server  20 , for example, identifies that audio data is taking all available bandwidth of communication links to one or more of the client devices  30 , the server  20  is operable to instruct a lower quality of audio transmission with associated lower data flow rates, for example reducing from 16-bit audio resolution to 10-bit audio resolution, or even 8-bit audio resolution in combination with audio dynamic range compression. 
     The system  10  is beneficially operable to apply a network optimization to the communication network coupling the client devices  30  in communication with the server  20 . Such network optimization is, for example, implemented by requesting a Maximum Transfer Unit (MTU) value from networks coupling the connected client devices  30  to the server  20 . It is thereby feasible to identify a weakest communication link in the communication network, and thereafter setting the Maximum Segment Size (MSS) for transmissions to a client device  30  associated with the weakest link at a rate which can be accommodated by the weakest link. This MSS value is optionally communicated by the server  20  to other client devices  30  of the system  10 . Such network optimization is beneficially implemented using a method having following steps: 
     Step 1: the system  10  determines a weakest data link coupling the server  20  to the client devices  30 ; for example, the MTU value for a given data link is 1500 Bytes. When this MTU value is subtracted by the number of TCP header Bytes, namely 40 Bytes, 1460 Bytes are available. These 1460 Bytes correspond to the MSS. 
     Step 2: the system  10  determines a MSS for a given session by employing the MSS of the weakest identified link. 
     Step 3: optionally, a Nagle algorithm employed in the system  10  is disabled in order to prevent congestion control within the system  10 , namely achieved by setting the TCP_NODELAY option on a socket of the system  10 , which disables the Nagle algorithm. Such disablement of the Nagle algorithm is desirable, because the Nagle algorithm waits before a certain amount of Bytes of data have been added to a transmission queue before a corresponding data packet is sent. When the Nagle algorithm is disabled, the system  10  is capable of sending a data packet of size determined solely by the system  10  as aforementioned. 
     A packet rate of full duplex, namely two-way communication, is an amount of packets communicated in a unit time. Moreover, the packet rate depends upon a protocol used for data communication within the system  10 ; when acknowledgements are necessary, an achievable packet rate in the system  10  decreases, because a transmitter of the system  10  has to retransmit a data packet if a corresponding acknowledgement is not received at the transmitter. A video signal frame includes one image, and corresponding data usually requires several network data packets to be sent. Moreover, an audio frame includes a designated amount of consecutive audio samples. For both video and audio data, both kinds of frame will have header Bytes in addition to its corresponding data. 
     If there is included quantity information and/or property information in an optional header section, for example indicative of time that the packets require to be communicated, indicative of the image area, or some other quantity, it is feasible to compute a consumption capability of a given client device  30  for such information. This consumption or absorption capability can be delivered with a remainder of the data, in which case each client device  30  and the server  20  are able to adjust a data transmission speed employed for this particular quantity or property. It is thereby feasible to balance between information types communicated within the system  10  by way of property flexibility, for example as a function of urgency and/or on a basis of resource requirements. A factor to be adjusted is, for example a relative packet rate information type and/or urgency type. The factor is capable of being used to balance information delivery within the system  10  on a per-client-device  30  basis, so that each client device  30  will receive a best possible experience when the system  10  is in operation. 
     In other words, it is feasible in the system  10  always to balance both the transmission and reception of data packets. Often, both the transmission and the reception of data packets are important, and operation of the whole system  10  is controlled accordingly in an optimized manner. However, occasionally, the transmission of data packets to one given client device  30  is more important than data packet transmission to another client device  30  of the system  10 . Moreover, the data communication rate when transmitting data packets can be very different from the data communication rate when receiving data packets, and such difference is taken into account when optimizing operation of the system  10 . 
     When communicating data in the system  10 , it is desirable that the data packet size is set to MSS (MTU-header) that is determined as described in the foregoing. Optionally, the relative packet rate information includes an Optional/Data section of the header. Moreover, communication delays occurring within the system  10  when in operation are beneficially computed by measuring differences and changes of achieved relative packet communication rates. Beneficially, each client device  30  computes the delay of recipients of data packets sent by the client device  30  using the relative packet rate information from the data that it has itself transmitted, and from the received packet rate information. 
     The packet rate can be defined, for example, on a basis of the interval of acknowledgements between the server  20  and the client devices  30  and/or by computing a time elapsed between a moment that a last packet of original data was transmitted and a moment when reception of the last data packet is acknowledged. Thus, in addition to the time needed for data transfer, the aforesaid packet rate mechanism is also capable of observing and assessing a time required for processing the received data, and therefore it is feasible for the system  10  to react to changes in processing times and to estimate a CPU processing load experienced at a receiving client device  30  of the system  10 . 
     The system  10  employs a tailor-made acknowledgement scheme that makes it possible to transmit data in a centralized manner, and yet bypassing the server  20 . Such a manner of operation is optionally achievable by, for example, using a UDP peer-to-peer communication approach in the system  10 . The UDP protocol as such does not use acknowledgements, but just transmits the datagram packets without checking whether they are received or not. Optionally, the UDP peer-to-peer communication method employed in the system  10  attaches an extra message into a last data packet of a connected sequence of data packets that announces to a receiving client device  30  that the sequence ends at the last data packet. 
     Moreover, once the UDP transmitter has registered at the server  20  and started communications with a given receiving client device  30  via the server  20 , it can thereafter send and receive a remainder of the communication directly with the receiving client device  30 . Thus, in  FIG. 2 , a client device B, denoted by  30 B, is desirous to send data via the server  20  and the Internet  60  as a communication network to a client device A, denoted by  30 A. The client devices  30 A,  30 B are protected via corresponding firewalls  70 ,  80  respectively. Communications  150 ,  160  enable an initial data exchange to occur between the client devices  30 A,  30 B via the server  20 , and thereafter implemented directly between the client devices  30 A,  30 B as denoted by a communication  170 . Beneficially, data is sent to a peer-to-peer port of the client device  30 A operable to receive the data. Data packets sent via the communication  170  are beneficially CPU-managed, as indicated generally by  200  in  FIG. 3 , by the client devices  30 A,  30 B. As illustrated in  FIG. 3 , each data packet type creates a thread  250  of its own inside a software application processing data and executing on a CPU  210 . The CPU  210  hosts multiple processes  240 , and the threads  250  are controlled via a memory stack  260  of the CPU  210 , wherein thread process results are sent from the memory stack  260  to a relevant corresponding thread  250 . Incoming data packets  230  are stored in an incoming packet queue  220  which feeds the processes  250 . Beneficially, each data packet  230  carries a sequence number in its header, and the last packet of the sequence announces the end of the sequence. 
     Each received data packet  230  is beneficially processed in its own thread  250  inside the application process  240  executing upon the CPU  210 . Moreover, the last data packet  230  in the incoming packet queue  220  raises an event that informs the processes  240  that the entire sequence of data packets  230  has been received in its entirety. For example, if the sequence of data packets  230  includes a hundred data packets, then each packet in a series 1 to 99 is received in their own respective threads  250  and terminated after processing via the CPU  210 , but the hundredth data packet  230  is detected as completing the sequence of data packets  230 . 
     The system  10 , for example in various different implementations as described in the foregoing, makes it possible to join in mutual communication very different sorts of client devices  30  using communication network infrastructures of mutually different quality into a same real-time communication session, for example a video conferencing session. As more client devices  30  are mobile, wireless devices which have relatively limited processing power that are prone to radio medium noise, the system  10  will become potentially increasingly important in future. Therefore, it is feasible to utilize the system  10  within existing information processing systems, without altering a communication protocol is use in the information processing systems, thereby enabling the system  10  to be implemented readily within existing communication networks, for example the Internet  60 . As elucidated in the foregoing, embodiments described in the foregoing makes it possible to communicate in real-time by simultaneously transmitting and receiving both time-critical primary data and non-time-critical secondary data. Such operation enables quality-of-service (QoS) to be achieved, independently of a protocol employed within a communication network supporting operation of the embodiments. 
     In the system  10 , there is enabled a maximum utilization of available communication network infrastructure by optimizing the Maximum Segment Size (MSS), and by prioritizing the data content of these MSS&#39;s. A benefit provided in operation in the system  10  is energy saving, because incomplete or partial network data packets  230  are not transmitted. As packet-based communication is increasing, in future, being implemented in battery-powered mobile communication devices, such energy saving is a crucial advantage. 
     Modifications to embodiments described in the foregoing are possible without departing from the scope of the invention as defined by the accompanying claims. Expressions such as “including”, “comprising”, “incorporating”, “consisting of”, “have”, “is” used to describe and claim the present invention are intended to be construed in a non-exclusive manner, namely allowing for items, components or elements not explicitly described also to be present. Reference to the singular is also to be construed to relate to the plural. Numerals included within parentheses in the accompanying claims are intended to assist understanding of the claims and should not be construed in any way to limit subject matter claimed by these claims.