Patent Publication Number: US-10326721-B2

Title: Real-time messaging method and apparatus

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a Continuation of U.S. application Ser. No. 15/710,627, filed on Sep. 20, 2017. U.S. application Ser. No. 15/710,627 is a Continuation of U.S. application Ser. No. 15/233,325 (P020FC3), filed on Aug. 10, 2016, now U.S. Pat. No. 9,800,528. U.S. application Ser. No. 15/233,325 is a Continuation of U.S. application Ser. No. 15/091,746 (P020FC2), filed Apr. 6, 2016, now U.S. Pat. No. 9,634,969. U.S. application Ser. No. 15/091,746 is a Continuation of U.S. application Ser. No. 14/839,266 (P020FC1), filed Aug. 28, 2015, now U.S. Pat. No. 9,338,113, which is a Continuation of U.S. application Ser. No. 12/857,486 (P020F), filed Aug. 16, 2010, now U.S. Pat. No. 9,178,916. U.S. application Ser. No. 12/857,486 (P020F) is a Continuation-in-Part of U.S. application Ser. No. 12/419,861 (P020A), Ser. No. 12/419,889 (P020B), Ser. No. 12/419,914 (P020C), Ser. No. 12/552,979 (P020D), now U.S. Pat. No. 8,688,789, and Ser. No. 12/552,980 (P020E), now U.S. Pat. No. 8,645,477, each claiming priority of U.S. Application No. 61/148,885 (P020P) filed Jan. 30, 2009. U.S. application Ser. No. 12/857,486 (P020F) is also a continuation-in-part of U.S. application Ser. No. 12/028,400 (P001), filed on Feb. 8, 2008, now U.S. Pat. No. 8,180,029, which claims priority of U.S. Patent Application Nos. 60/937,552 (P001P) filed on Jun. 28, 2007 and 60/999,619 (P001P2), filed on Oct. 19, 2007. All of the above-listed applications are incorporated herein by reference for all purposes. 
    
    
     BACKGROUND 
     Field of the Invention 
     This invention pertains to communications, and more particularly, to a late binding communication system and method for real-time communication of time-based media. 
     Description of Related Art 
     Currently there are three globally used addressing domains. The postal system, which is mainly used for the delivery of letters and parcels, relies on the use of a physical address, such as a house address, office building address or Post Office (PO) box. In order to assure the delivery of a letter or parcel, the physical address of the recipient must be provided, including a country, state or territory, a city or town, postal or zip code, street name and street number. The existing telephone infrastructure defines another global addressing domain that has historically been used for near real-time voice communications (i.e., telephone calls). Both land-line and mobile telephones are addressed (i.e., called) using a telephone number, which typically includes a country code and a variable number of additional digits to identify a particular phone within a given country and/or area code. When a circuit connection is made between the calling parties, a full duplex conversation may take place. A third global addressing system is email. Every email account is identified by a unique globally addressable email address, which defines a user name and a domain name. 
     Emails are typically text messages that are sent from a sender to one or more recipients. The emails are created on an email client. One well-known email client is Microsoft Outlook, which is used to create, receive and manage email messages on a computer. Alternatively, free email services like Yahoo, Google or Hotmail are available to users through a web page. Regardless of the type used, an email client will typically (i) list or display all the received messages, with an email header showing the subject of the email, the sender of the email, the date/time it was sent and possibly other attributes such as the size of the email; (ii) allow the user to select messages for review; (iii) allow the user to type and send new messages to recipients and reply to the received emails of others; and (iv) allow attachments, such as still photos, documents, or video clips, to be attached to an out-going email. 
     An email message must first be created in full before it can be sent. A sender will typically first define a recipient by entering their email address into the appropriate “To” field in the header of the email. The text message is then typed into the body of the email and files may optionally be attached. When the message is complete, the user sends the email. During the send sequence, the email client initiates a session with its email server located on a network. This session is typically established with the Simple Mail Transport Protocol (SMTP). During the session, the email client provides the SMTP server with the email address of the sender, the email address of the recipient, and the body of the email with any attachments. The email addresses of the recipient is segmented into two parts, including the recipient&#39;s name (e.g., “jsmith”) and the domain name (e.g., “hotmail.com”). If the recipient is in a domain that the SMTP server controls, then the server carries out delivery instructions for the specific recipient, which is typically delivery of the email to an in-box associated with the recipient on the same SMTP server or another server located in the same domain. On the other hand if the recipient is in a domain that the server does not control, then the email server needs to communicate with a server that controls the recipient&#39;s domain using SMTP. 
     To send the email to the recipient in another domain, the SMTP server initiates a conversation with the Domain Name System (DNS), asking for the Mail eXchanger (MX) record of the recipient&#39;s domain. This MX record contains a prioritized list of SMTP servers for that domain. The email is then sent from the SMTP server of the sender to the first SMTP server in the MX list that responds. This first responding server then determines if the recipient is in the domain the first responding server controls. If so, the email is delivered to the inbox of the recipient. If not, the above-described process is repeated until a responding server is the one that can deliver the message into the recipient&#39;s inbox. Each server along the delivery route is sometimes referred to as a “hop”. Once in the inbox, the email may be accessed through the email client of the recipient, which may be located on the computer of the recipient or on the Internet. If an email is sent to multiple parties, the above-described process is repeated for each recipient. 
     The above-described sequence generally applies for emails sent over the Internet. With certain proprietary systems, such as an email sent between two Microsoft Exchange users on the same proprietary network, the SMTP protocol may not be used for routing the email but email addresses are still used. The operation of the proprietary protocol and server is essentially the same as SMTP. 
     The existing email infrastructure, regardless if it relies on SMTP or a proprietary email protocol, is essentially a “store and forward” messaging system. An email message must first be created in its entirety before it can be sent. At the SMTP or proprietary mail server of the sender, as well as any intermediate email server hops along the path to the SMTP or proprietary mail server of the recipient, the email message must be received in full before it can be forwarded. Finally the email must be received in full at the inbox of the recipient before the recipient can review the message. 
     By way of comparison, telephone conversations over the Public Switched Telephone Network (PSTN) are progressive in nature. As words are spoken, they are simultaneously transmitted from the sender to the recipient, where they are heard effectively live or near real-time. As a result, telephone conversations can be conducted in a “live” or near real-time mode through a common network connection (i.e., a circuit). Email communication in contrast usually occurs through a series of separate store and forward messages, often sent back and forth between two or more parties at distinct times, across a network, such as the Internet. 
     It is well known to attach a file to an email containing time-based media (i.e., media that changes with respect to time), such as a video clip. The time-based media attached to an email message, however, can never be reviewed by a recipient “live”, as it is being created, due to the store and forward nature of email. Rather the email and the attachment containing the time-based media must first be created, sent, stored and forwarded at each email server hop on the network, and then received by the recipient in full before the time-based media of the attachment can be reviewed. It is therefore not possible for the recipient of an email message to review the media in near real-time as the media is being created. 
     Telephone messaging systems are also known where a voice message may be created and sent to a recipient in the form of an email. With these systems, the Public Switched Telephone Network (PSTN) is used in cooperation with emails. In use, a recording of the message must first be made, stored, and then forwarded to the recipient by email. Again, however, the message must first be received in full before the recipient can review the recorded message. 
     Instant messaging or IM is another example of a store and forward system. Similar to email as described above, messages must be completed before they can be forwarded to a recipient. Messages in IM systems are generally much shorter than those sent via email. Each line of text in IM systems is a separate message delivered in a store and forward manner. Existing IM systems do not provide a way for a recipient to progressively and simultaneously review a message as the sender creates the message. 
     “Live” text systems are well known, although they were mostly used on early Unix systems with dumb terminal interfaces. These text systems, give the appearance of being “live” since each individual keystroke is sent to the recipient as soon as the sender pressed that key. But in reality, these systems are actually store and forward based, where the transmission of each keystroke is a discrete event. These systems are for text only (i.e., non time-based media only) and they do not allow the recipient to progressively review the media in real-time per se. 
     In the context of communications, a recipient address can be described as “bound” when a valid delivery path across the network has been determined for that address. Conventional telephone calls over the PSTN are said to use “early binding” because the dialed phone number, the “recipient address” in this case, is used to establish some active path (i.e., a circuit connection) to the recipient before any media can be transmitted to the recipient. Only after the connection is made can the caller begin speaking and the media transmitted. Regardless if the call is placed to one or more telephone numbers, or the call is transferred to a voice messaging system, the binding typically occurs before any words can be delivered. Since the binding of the recipient&#39;s address to an active destination on the network happens before any transmission of media, it is said to be “early”. In contrast, emails are said to employ “late” binding. A person may compose an email message and send it over a network without binding that message to the device on which the recipient will consume it. Instead, after the email is composed, the email address of the recipient is used to route the email to the recipient to be reviewed on a device and at a time of the recipient&#39;s choosing. Since late binding systems require the completion of a message before it can be sent, late binding systems cannot be used for “live” communication. 
     SUMMARY OF THE INVENTION 
     The present invention solves many of the problems of the prior art by providing a late binding communication system and method for real-time communication of time-based media. With late binding, a sender has the ability to transmit time-based media before or at the same time as an active delivery route over a communication network to the recipient is discovered. As soon as the delivery route becomes at least partially known (i.e., the next hop), the sender may transmit available time-based media. By providing both the sender and each server hop with the ability to transmit available media as soon the next hop is discovered, time-based media may be transmitted to the recipient in real-time before the complete delivery route to the recipient is fully known. Late binding thus solves the above-described problems, namely the (i) waiting for a circuit connection to be established before communication may take place, with either the recipient or a voice mail system associated with the recipient, as required with conventional telephony or (ii) waiting for an email to be composed in its entirety before the email may be sent. 
     In one non-exclusive embodiment, the invention uses the existing global addressing and routing infrastructure of email to support real-time communication of time-based media. With this embodiment, the sender defines the email address of the intended recipient. As soon as the email address is defined, a delivery route to the recipient is discovered using the existing DNS infrastructure and DNS lookup results of the email address. A real-time communication protocol is used for the actual delivery of the time-based media to the recipient as the delivery route is discovered. 
     In another non-exclusive embodiment, an email client that is capable of sending “progressive” emails is used. Like conventional emails, progressive emails include a header that has one or more fields for defining the email address for one or more recipients. Progressive emails, however, differ from conventional emails in at least two regards. With progressive emails, a delivery route to the recipient is discovered as soon as the email address of the recipient is defined, rather than after the body of the email is composed and the email is sent. The body of progressive emails is dynamic, not static, as with conventional emails. Consequently as time-based media associated with the email is created, it is progressively transmitted to the recipient using the route discovered as soon as the email address of the recipient is defined. By further modifying the access protocols used in cooperation with convention email protocols, the recipient may also review the incoming time-based media of progressive emails in real-time as the media is received. In variations of this embodiment, the email client may reside on a server or on a communication device of the sender and the progressive email may be delivered to an inbox associated with the recipient located either at a server associated with the recipient and/or on the communication device of the recipient. 
     The invention may also be used in cooperation with a messaging system where the time-based media of transmitted and received messages is progressively stored as either as the media is created or received respectively. With the progressive storage of time-based media, a recipient may review incoming messages either (i) synchronously in a real-time mode, (ii) asynchronously in a time-shifted mode and (iii) seamlessly transition the review of a message between the two modes. In addition, the messaging between two or more parties may be either half or full duplex, the latter providing a user experience similar to a conventional telephone call. Another advantage associated with the storage of created media is the ability to provide limited communication capabilities when the communication device of a user is disconnected from the network. A user of a cell or mobile phone for example will often roam into regions beyond network coverage, or into areas where network coverage is weak or non-existent. When this occurs, the user can still create a message for a recipient while disconnected from the network. When the user roams back into an area of network coverage, the message is transmitted out of storage. The storage of media of incoming messages also allows the recipient to review the messages from storage, in the time-shifted mode, when disconnected from the network. 
     In other embodiments, the sender and recipient may communicate over a communication network using either a client-server model or a peer-to-peer model. In another embodiment, messages for a recipient may be posted and accessed on a web server. In yet another embodiment, identifiers other than globally unique email addresses may be used for identifying a recipient and for routing purposes. This invention is therefore not limited to the use of globally unique email addresses, but rather, may be used with any type of identifier. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention may best be understood by reference to the following description taken in conjunction with the accompanying drawings, which illustrate specific embodiments of the invention. 
         FIG. 1  is a diagram of an exemplary network capable of supporting live or near real-time communication of time-based media between users according to the principles of the invention. 
         FIG. 2  is a diagram of a first exemplary communication device according to an embodiment of the present invention. 
         FIG. 3  is a diagram of another exemplary communication device according to another embodiment of the present invention. 
         FIGS. 4A and 4B  are flow diagrams illustrating one possible example of the sequence for creating an email header on a communication device according to the principles of the present invention. 
         FIGS. 5A through 5D  are flow diagrams illustrating possible embodiments of the sequence for conducting communication over a network in accordance with the principles of the present invention. 
         FIG. 6  is a flow diagram illustrating an embodiment for the attachment of a media file to an email in accordance with the principles of the present invention. 
         FIG. 7  is a diagram illustrating another embodiment for the delivery of time-based media over the network in accordance with principles of the present invention. 
         FIG. 8  is a diagram illustrating the structure of a conventional email according to the prior art. 
         FIG. 9  is a diagram of one possible embodiment of a progressive email according to the principles of the present invention. 
     
    
    
     Throughout the Figures, like reference numbers refer to like elements. 
     The above-listed figures are illustrative and are provided as merely examples of embodiments for implementing the various principles and features of the present invention. It should be understood that the features and principles of the present invention may be implemented in a variety of other embodiments and the specific embodiments as illustrated in the Figures should in no way be construed as limiting the scope of the invention. 
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS 
     The invention will now be described in detail with reference to various embodiments thereof as illustrated in the accompanying drawings. In the following description, specific details are set forth in order to provide a thorough understanding of the invention. It will be apparent, however, to one skilled in the art, that the invention may be practiced without using some of the implementation details set forth herein. It should also be understood that well known operations have not been described in detail in order to not unnecessarily obscure the invention. 
     I. The Use of the Email and DNS Infrastructure to Define the Routing for the Delivery of Messages Containing Time-Based Media Using a Near Real-Time Communication Protocol for the Actual Delivery of the Media 
     Referring to  FIG. 1 , a diagram of a representative network system capable of (i) supporting “live” or near real-time communication of time-based media and (ii) routing using the infrastructure of email and DNS according to one possible embodiment of the invention is shown. The system  10  includes a network  12  with users A, B, C and D using communication devices  14 A,  14 B,  14 C and  14 D and Servers  16 A,  16 B,  16 C and  16 D located on the network  12 . The network  12  further includes a DNS server  18 . In various embodiments, the network  12  may include the Internet, an intranet, a mobile IP network, or any other type of network that relies on the Internet Protocol and/or DNS, or any combination thereof. Users A, B and C are each addressed by the servers  16 A through  16 D by their respective globally addressable email addresses “UserA@Domain A”, “UserB@Domain B”, and “UserC@Domain C”. User D is intentionally not identified on the network  12  by a globally addressable email address for reasons mentioned below. 
     The Servers  16 A,  16 B,  16 C and  16 D are each configured to provide one or more services to Users A, B, C and D respectively. In this example, Server A defines Domain A and provides User A with the standard email delivery service using SMTP (or a similar proprietary or non-proprietary service) and MX DNS records, hereafter referred to as “MX”. Server A further provides User A with a real-time communication service, hereafter referred to as “RVX”. Server  16 B defines Domain B and provides User B with the real-time communication service RVX, but not the email service MX. Server  16 C defines Domain C and provides User C with the email service MX, but not the real-time domain RVX service. Server  16 D does not provide user D with either the real-time communication service RVX nor the email domain MX service, but possibly other services that are not identified because they are not relevant. 
     In one embodiment, the real-time service RVX may rely on any communication protocol that allows users to communicate time-based media in near real-time, but does not require the recipient to review the time-based media in a near real-time mode. Known protocols with these properties include the Cooperative Transmission Protocol (CTP) described in detail in the U.S. application Ser. No. 12/028,400 and Ser. No. 12/192,890 or the near real-time synchronization protocol of voice or other time-based media as described in U.S. application Ser. Nos. 12/253,816, 12/253,833 and 12/253,842. The above-listed U.S. applications are assigned to the assignee of the present invention and are incorporated herein by reference for all purposes. 
     In alternate embodiments, the RVX service may rely on other communications protocols, individually or in combination, that provide near real-time communication, such as SIP, RTP, Skype, VoIP, etc. 
     The communication devices  14 A through  14 D may each be any type of communication device, such as land-line telephones, VoIP telephones, cellular radios, satellite radios, military or first responder radios, mobile Internet devices, or just about any other type of communication device. In addition, a given user might have multiple communication devices  14 . For example, a user may have one or more of the following; a home computer, a work computer, a Push to Talk radio, a mobile phone or a personal digital assistant (PDA). Regardless of the number of communication devices  14  each user A, B, C and D has, each will operate essentially the same and receive the services provided by the servers  16 A,  16 B,  16 C and  16 D as described herein respectively. 
     It should be noted that the system  10  as illustrated has been greatly simplified compared to what would typically be implemented in actual embodiments. For the sake of illustration, the RVX and MX services as (or not) provided to Users A, B, C and D as listed above have been purposely selected to highlight and describe certain features and principles of the invention. In actual embodiments, however, there would likely be a significantly larger number of users, each with one or more communication devices  14  and associated servers on the network  12 , providing a variety of services to each user. In addition, any combination ranging from a single server or a suite of servers  16  may be included on the network  12  to provide the RVX and/or MX for one to multiple users respectively. The communication devices  14 A,  14 B and  14 C and the servers  16 A,  16 B and  16 C may also communicate with one another in a manner similar to that described above using DNS, SMTP, or other proprietary or non-proprietary email protocols for route discovery across one or more hops on the network  12 . 
     The delivery route for a message to a recipient in the same domain is typically delivered to an inbox on the same server  16  or an associated server in the same domain. A message sent to a recipient in another domain will typically be sent to the email server of the recipient via one or more hops across the network  12 . With each hop, the media is transmitted using the real-time protocol as soon as the delivery path to the next hop is discovered. If multiple hops are required, then media is typically being transmitted between hops using the real-time protocol before the complete delivery route to the recipient is known (i.e., the path through subsequent hops). This differs significantly from convention emails, where the body of the email is typically first received in full and stored at each hop and forwarded to the next hop only after the route to the next hop is discovered. 
     Referring to  FIG. 2 , a diagram of a communication device  14  according to one embodiment of the present invention is shown. In this embodiment, the communication device  14  is a mobile device  20  capable of wirelessly communicating with the network  12 , such as a mobile phone or PTT radio. The mobile device  20  may optionally include one or more of the following; a keypad  22 , a display  24 , speaker  26 , microphone  28 , volume control  30 , camera  32  capable of generating still photos and/or video, a display control element  34 , a start function element  36  and an end function element  38 . In various embodiments, the device  20  (i) is IP based, meaning it is designed to communicate over the network  12  using the Internet Protocol and (ii) runs one or more RVX protocols, including any of those listed above or any other near real-time communication protocol. In addition, the mobile device  20  may optionally also locally run an email client, access an email client located on one of the servers  16  located on the network  12 , or be capable of both running and accessing an email client on the network. 
     Referring to  FIG. 3 , a diagram of a communication device according to another embodiment of the present invention is shown. In this embodiment, the communication device  14  is a computer  40  connected to the network  12 , either through a wired or wireless connection (not shown). The computer  40  optionally includes one or more of the following; a keyboard  42 , a display  44 , speakers  46 , a microphone  48 , a camera  50  capable of generating still photos or video, a mouse  52 , a start function element  54  and an end function element  56 . The computer  40  is capable of running an email client, accessing an email client located on the network  12 , or both. In various embodiments, the computer  40  (i) is IP based, meaning it is designed to communicate over the network  12  using the Internet Protocol and (ii) runs one or more RVX protocols, including any of those listed above or any other near real-time communication protocol. The computer  40  could be a portable computer, such as a laptop or personal digital assistant, and is not limited to the desktop computer as shown. In addition, the computer  40  may optionally also locally run an email client, access an email client located on one of the servers  16  located on the network  12 , or be capable of both running and accessing email client on the network. 
     The start function elements  36 / 54  and the end function elements  38 / 56  of the mobile device  20  and computer  40  are meant to be symbolic of their respective functions. It is not necessary for mobile device  20 , computer  40 , or any other type of communication device  14 , to physically include start and end buttons per se. Rather, it should be understood that each of these functions might be implemented in a variety of ways, for example, by entering a voice command, a predefined keystroke or command using a touch screen or other input device such as a mouse, stylus or pointer, etc. In one specific embodiment, the start and/or end functions may be implemented by default. In other words, the start function may automatically be implemented by the creation of media after the email address of a recipient is defined. For example, a sender may select a recipient from their contacts list, and then begin talking or creating other time-based media. By virtue of defining the recipient and the creation of media, the “start” function  34  may automatically be implemented. Similarly, the end function may be implemented by default. After the sender stops creating media, the end function may automatically be implemented after a predetermined period of time. 
     In one non-exclusive embodiment, the network  12  uses the existing email infrastructure, including the globally recognizable email addresses of the recipient users and DNS for route discovery, while using a near real-time RVX protocol for the actual transport of messages containing time-based media to the addressed recipient once the route is discovered. Like conventional emails, each message relies on a header that defines, among other things, a globally addressable email address of one or more recipients for routing purposes. Unlike conventional store and forward emails, however, the time-based media of the message is transmitted using a near real-time RVX protocol. As a result, time-based media may be simultaneously and progressively transmitted across the network  12 , as the sender creates the media. In addition, the recipient may optionally simultaneously and progressively render the time-based media as it is received over the network. 
     When two or more parties are conversing (e.g., generating and reviewing time-based media) at approximately the same time, the network  12  is supporting full-duplex, near real-time communication, using one or more RVX protocol(s) for media delivery, while using the existing email infrastructure and DNS for routing. With full duplex real-time communication, the user experience is very similar to a conventional telephone conversation, except the hassles of dialing a telephone number and waiting and listening to the phone ring while a circuit connection is established is avoided. 
     Alternatively, if the recipient does not reply at approximately the same time, then the user experience is similar to an asynchronous messaging system, such as voice mail, but again without the hassles of dialing the telephone number of the recipient, listening to the phone ring while the establishment of a circuit connection is attempted, and then the eventual rolling-over into the voice mail system of the recipient. On the contrary, the sending party simply has to select or otherwise define the email address of the recipient and then start generating media. The media is routed to the recipient automatically without waiting for a circuit connection to be established. 
     Referring to  FIG. 4A , a flow diagram illustrating one possible sequence for creating and transmitting time-based media associated with a message on a communication device  14  in accordance with the principles of the present invention is shown. If the user of a communication device  14  wishes to communicate with a particular recipient, the user will either select the recipient from their list of contacts or reply to an already received message from the intended recipient. Alternatively, the globally addressable email address of the recipient is manually entered into the device  14 . 
     As soon as the email address of the recipient is defined, two operations are performed. A message header is created (step  62 ) and the defined email address is included in a header field (i.e., the “To”, CC, and/or “BCC” field). In addition, the route for delivering the media associated with the message to the globally addressed recipient is immediately discovered using a DNS lookup result. The result can be either an actual DNS lookup or a cached result from a previous lookup. Thereafter, the start function  36 / 54  is initiated, either manually or by default, and the user may begin creating time-based media (step  64 ), for example by speaking into the microphone, generating video, or both. The time-based media is then progressively and simultaneously encoded (step  66 ), transmitted (step  68 ) over the network  12  using an RVX protocol using the discovered delivery route, and optionally persistently stored on the device  14  (step  70 ). It should be noted that although these steps  62  through  70  are illustrated in the diagram in a sequence, for all practical purposes, they occur at substantially the same time. As the media is created, the RVX protocol progressively and simultaneously transmits the media across the network  12  to the recipient, as the route is typically discovered without any perceptible delay to the sending user. 
     The time-based media of outgoing messages may optionally be persistently stored on the sending communication device  14  for a number of reasons. For example, if time-based media of a message is created before the delivery route is discovered, then the time-based media may be transmitted from storage when the delivery route at least to the next hop is discovered. If time-based media is still being created after the route is discovered, then the time-based media is transmitted progressively and simultaneously as the media is being created. Alternatively with the storage of time-based media, the sender may review stored outgoing messages at an arbitrary later time. A message may also be created and stored when the communication device  14  is not connected to the network  12 , where connected is defined as the ability to send messages over the network and not connected is defined as the inability to send messages over the network. When the device  14  later connects, the message may be transmitted to the intended recipient from storage, using either an RVX protocol or as an attachment to an email. 
     Referring to  FIG. 4B , a flow diagram  100  illustrating one possible sequence for creating a message header (step  62  in  FIG. 4A ) in accordance with the principles of the invention is shown. In the step  62   a , the globally addressable email address of the sender is provided in the “From” field of the message header. In step  62   b , the globally addressable email address of the recipient is entered into the “To” field of the message header. If there are multiple recipients, the email address of each is entered into the “To” field. In additional embodiments, a “CC” or “BCC” field may be used for one or all recipients. In step  62   c , a globally unique message ID or number is assigned to the message. In step  62   d , other information, such as a conversation name, or the subject of the message, is provided in the header. In step  62   e , the start date/time the message was created and possibly the end date/time of the message may be included in the header. In one embodiment, the steps  62   a  through  62   e  generally all occur at substantially the same time, with the possible exception of defining the end date/time. In other embodiments, the steps  62   a  through  62   e  may occur in any order. The start and end date/times ordinarily coincide with the implementation of the start function  36 / 54  and end function  38 / 56  on the sending device  14  respectively. 
     In certain embodiments, the steps  62   a  through  62   e  may be performed on a sending communication device  14 . In other embodiments, the sending communication device may send some or all of the message header information to a server  16 , where the steps  62   a  through  62   e  are performed. The time-based media of the message may also be optionally stored on a server  16  for later review by the sending user or transmission to the recipient. 
     In the embodiments described above, a message header with various fields including a To, From, Message ID number, Conversation Name, and message Start and End time is provided. It should be understood that not all of these fields are necessary, and other fields may be included. The only required information is at least one recipient specified in one of the To, CC, or BCC fields, which defines the globally addressable email address of a recipient. The other fields are all optional. 
     The format of the message header is also variable. In one embodiment, the structure of the message header may be similar to that used with conventional emails or the enveloped used with emails. In other embodiments, the structure of the message header may take any form that is suitable for transmitting the globally addressable email address of the recipient(s), along with possibly other header information, across the network  12 . While specific email header fields are discussed for specifying recipients, the actual header field containing the recipient address information may not necessarily include the globally addressable email address of the recipient per se. As is well known in the art, an “envelope recipient” may be used to specify the email address of the recipient, even though the envelope recipient may differ from the recipients listed in the email headers. Thus as used herein, the term message header should be broadly construed to include both envelope information and conventional message or email headers including any number of fields, such as but not limited to those specified in RFC 822 or 5322. In addition, the usage of the terms “addressing” or “globally addressable email address” should be broadly construed to include any addressing method, including usage in conventional message or email headers or in a message envelope. 
     The network  12 , under certain circumstances, may deliver messages containing time-based media that can (i) be simultaneously and progressively transmitted to a recipient over the network  12  and (ii) reviewed in near real-time by the addressed recipient as the time-based media is being created and sent by the sending user. Under other circumstances, the messages cannot be delivered in real-time. Both the near real-time and non real-time scenarios are discussed below with regard to  FIGS. 5A through 5C  respectively. 
     Referring to  FIG. 5A  a flow diagram  80  illustrating one possible sequence for conducting near real-time communication with messages containing time-based media in accordance with the principles of the present invention is shown. The sequence is described in the context of user A sending a message to user B using any near real-time RVX protocol. As noted above, server  16 B provides user B with an RVX service, but not the MX service. In this example, the steps  62  through  70  as described above with regard to  FIGS. 4A and 4B  may occur either on the communication device  14 A of the sender or the server  16 A. 
     In the initial step  82 , server  16 A receives the message header (or the header information allowing the server to perform some or all of the steps  62   a - 62   e ). As soon as user B&#39;s globally addressable email address (userB@DomainB) is received, server  16 A requests that DNS server  18  using standard DNS protocols perform a DNS lookup of domain B or accesses a previously cached lookup for the RVX of domain B (step  84 ). Regardless of how obtained, the result is positive (decision  86 ) since the RVX exists for domain B. Typically at substantially the same time, the server  16 A receives the time-based media of the message. As soon as the delivery path to server  16 B is at least partially known, the media is progressively and simultaneously sent using the RVX protocol from the server  16 A to server  16 B. The time-based media may be transmitted across one or more hops between the two servers  16 A and  16 B. At each hop, a DNS lookup result is used to discover the delivery route to the next hop, while the RVX protocol is used to deliver the time-based media to each next hop. 
     In one embodiment, the media is simultaneously and progressively transmitted to the communication device  14 B of the recipient when the time-based media arrives at server  16 B. The recipient is notified of the incoming message, and in response, the recipient may elect to simultaneously review the media in the near real-time mode as the media of the message is progressively received. 
     In an alternative embodiment, the media of the message is also optionally placed in an inbox and persistently stored on the recipient device  14 B. With the persistent storage of the message, the recipient has the option of reviewing the media in the near real-time mode as the media is received or at an arbitrary later time from storage. 
     In yet another embodiment, the message may also be stored in an inbox located at the server  16 B associated with the user B. In this manner, the user of device  14 B may access the message in either real-time or at an arbitrary later time. As noted above, user B is not provided the MX service and therefore cannot receive emails. But in situations where recipient can receive emails, the message can be encapsulated into a file and the file attached to an email that is forwarded to the inbox of the recipient. 
     In yet other embodiments, the media of the message may be stored in an out-box of the sending user, either located on the user&#39;s sending communication device  14 A, or on the server  16 A associated with the sender. 
     Referring to  FIG. 5B , a flow diagram  80  illustrating one possible example of the communication sequence between user A and user C in accordance with the principles of the invention is shown. As previously noted, server  16 C provides user C with the MX service, but not a real-time RVX service. When user A wishes to communicate with user C, the initial sequence is essentially the same as that described above. Server  16 A initially receives a message header (or the header information necessary to optionally perform steps  62   a - 62   e ) with the globally addressable email address of user C (userC@domainC) and the progressive and simultaneous transmission of time-based media by user A (step  82 ). Since the RVX lookup result (decision  86 ) is negative, server  16 A performs a DNS lookup or uses a previously cached MX lookup for domain C (step  90 ). With a positive result (decision  92 ), server  16 A sends a conventional email with the time-based media encapsulated as an attachment (step  96 ) to server  16 C. At the server  16 C, the email is placed in the recipient&#39;s inbox. The email may also be forwarded to an inbox on communication device  14 C. Thus, when the recipient does not have the RVX service, the time-based media of the message is sent across the network  12  by Server  16 A to server  16 C, and possibly communication device  14 C, using the store and forward procedure of SMTP or a similar proprietary or non-proprietary email protocol. 
     Referring to  FIG. 5C , a flow diagram  80  illustrating one possible example of the communication sequence between user A and user D in accordance with the principles of the invention is shown. As previously noted, user D is not provided with either the email MX service or a near real-time RVX service. When user A wishes to communicate with user D, the initial sequence is essentially the same as that described above. Server  16 A receives a message header with the globally addressable email address of user D (userD@domainD) and the progressive transmission of time-based media by user A (step  82 ). Since the RVX lookup (decision  86 ) and the MX lookup for domain D (diamond  92 ) are both negative, an error message is generated (step  94 ) and the message cannot be delivered (step  96 ). In various embodiments, the time-based media of the message may be stored at either the sending communication device  14 A, the server  16 A, or both. The message may later be sent when the RVX and/or MX service is provided to user D. 
     The scenario described with regard to  FIG. 5C  typically occurs if an incorrect email is provided for a recipient. When the sender attempts to send a message using an invalid email address, the error message (step  94 ) results. If the correct email address is provided, the message can then be forwarded using either an RVX protocol or as an attachment to an email using the MX service, depending on the services provided to user D. 
     In an alternative embodiment, the communication devices  14 A through  14 C may be arranged in a peer-to-peer configuration. With this arrangement, at least the sending communication devices  14  are capable of performing the RVX and/or MX lookups on DNS server  18  directly and caching the results, without the aid of an intervening server  16  to perform the these functions. The communication devices  14  may also be capable of progressively transmitting the media of the messages directly to other communication devices. Depending on whether the recipient is a member or not of the RVX and/or MX domains, the sending communication device  14 A will either (i) progressively transmit the time-based media of a message to the recipient over the network  12  as the media is created; (ii) encapsulate the time-based media of the message into a file and transmit an email including the file as an attachment to the recipient using SMTP or a similar proprietary protocol; (iii) or receive an error message if an invalid email address was used. 
     Referring to  FIG. 5D , a flow diagram illustrating one possible example of peer-to-peer communication in accordance with the principles of the invention is shown. In the initial step  101 , a sending communication device  14  indicates that it would like to communicate with a receiving communication device  14 . In decision diamond  102 , the communication device  14  of the sender relies on either an actual or cached DNS lookup result of the recipient&#39;s globally addressable email address to determine if the peer recipient receives the RVX service. If the result is positive, then the time-based media created (step  103 ) using the sending communication device  14  is progressively transmitted (step  104 ) to the recipient as it is created using the delivery route defined by the RVX lookup. In decision diamond  105 , it is determined if real-time communication is established. If yes, then the transmitted media is progressively rendered at the communication device  14  of the recipient as the media is received (box  106 ). If real-time communication is not established, then the media of the message is placed in the inbox of the recipient (box  107 ), either on the device  14  of the recipient, a server  16  associated with the recipient, or possible both. Real-time communication may not take place with the recipient for a number of reasons, such as the recipient is not available, out of network range, or has indicated a desire to not review the message in the near real-time mode. In another alternative embodiment, the message may always be placed in the inbox of the recipient, regardless if it is reviewed in real-time. 
     On the other hand, if the recipient does not receive the RVX service (decision  102 ), then the media of the message is delivered by email, provided the recipient receives the MX domain service. The time-based media is encapsulated into a file and attached to an email (step  108 ). When the message is complete, the email is transmitted using the route defined by the MX lookup result (step  109 ) to the inbox of the recipient. In various embodiments, the inbox may be located on the device  14  of the recipient, a server  16  associated with the recipient, or both. 
     In situations where both peers are running an email client, media may be sent in the form of an attachment to an email from the sending communication device  14  to the receiving communication device  14 . This differs from known telephone messaging systems, where a server, as opposed to a sending peer, emails a voice message to the recipient. In certain embodiments, an attachment may be substituted or augmented by a link to a web page containing the time-based media, as described in more detail below. 
     It should be noted that the discussion above with regard to  FIGS. 4A, 4B and 5A through 5C  has been simplified to illustrate certain aspects of the invention. It should be understood that actual implementations could be modified in several ways. For example, each time the server  16 A received an email address, the server  16 A would first determine if the domain of the recipient (i.e., domain A, domain B or domain C), is within one or more local domains of the server  16 A. If not, then the procedures described above with regard to  FIGS. 5A, 5B and 5C  are performed respectively. On the other hand if the domain of the recipient is within a local domain of the server  16 A, then the server  16 A may deliver the message directly to the recipient either (i) in real-time if the recipient receives a real-time communication service or (ii) as an attachment to an email if the recipient receives the MX service, but not a real-time service. In addition, it may not be necessary for the Server  16 A to perform a DNS lookup in each instance. As is well known, previous DNS lookup results may be cached and used rather than performing a new DNS lookup each time an email address of a recipient is received. 
     Referring to  FIG. 6 , a flow diagram  110  illustrating one possible sequence for sending time-based media encapsulated in an email attachment in accordance with the principles of the invention is shown. When the time-based media of a message is to be sent in the form of an email (e.g., box  98  in  FIG. 5B  or box  107  in  FIG. 5D ), the time-based media generated by user A is first encapsulated in a file (step  112 ). The file is then attached to the email (step  114 ) when the message is complete. When the time-based media of the message is complete, the email with the attachment is then transmitted (step  116 ) to the MX lookup result of the recipient in a manner similar to a conventional email. 
     With either the server or peer-to-peer models described above, the RVX lookup result is initially used to deliver the time-based media. If the RVX attempt fails, then the MX result is used as a backup. With this arrangement, a conventional email with the time-based media included in an attachment and/or web link is used to deliver the media in circumstances where the recipient is not provided RVX service. The email may be created either on a server or on the sending device. 
     II. Delivery Options 
     Referring to  FIG. 7 , a diagram illustrating another embodiment for the delivery of time-based media over the network  12  in accordance with the principles of the invention is shown. With this embodiment, the network  12  is essentially the same as that described above with regard to  FIG. 1 , with at least one exception. One or more of the servers  16 A- 16 C are configured as web servers, in addition to providing the RVX and/or MX services as described above. With this embodiment, users receive an email from their respective server  16  containing a URL link when a message is sent to them. When the user selects the link through a web browser running on their communication device  14 , the appropriate web server  16  serves up web pages allowing the recipient to access and review the message. The served web pages may also provide a variety of rendering options, such as review the media of the message in either the real-time or time-shifted modes, catch up to live, pause a live conversation, jump to the head of a conversation, jump to a previous point in time of the conversation, render faster, render slower, jump between different conversations, etc. In the figure, the web server functionality is provided as one of the services provided by servers  16 A,  16 B and/or  16 C. In an alternative embodiment, the web server functionality can be implemented using one or more other dedicated web servers (not illustrated) on the network  12  besides  16 A,  16 B or  16 C. 
     III. Email Protocol Modifications and Progressive Emails 
     The messages as described above are routed using globally addressable email address and the DNS infrastructure for defining a delivery route, while using an RVX protocol for the actual delivery of the time-based media in near real-time. Although the SMTP and other proprietary and non-proprietary email protocols as currently defined and used are essentially store and forward protocols, with certain modifications, these protocols can be used as an RVX messaging protocol for the near real-time delivery of time-based media as contemplated herein. With conventional emails, the media content must be composed in full and packaged before the email can be sent. On the receiving end, the email must be received in full before the recipient can review it. As described in detail below, SMTP, Microsoft Exchange or any other proprietary email protocol may be used for creating “progressive” emails, where media may be sent in real-time. 
     The existing email infrastructure can be used to support the real-time transmission of time-based media by modifying the way the SMTP, Microsoft Exchange or other proprietary and non-proprietary email protocols (hereafter generically referred to as an email protocol or protocols) are used on the sending side and modifying the way that emails are retrieved from the server on the receiving side. Current email protocols do not strictly require that the entire message be available for sending before delivery is started, although this is typically how email protocols are used. Time-based media can therefore be delivered progressively, as it is being created, using standard email protocols. 
     Email is typically delivered to a recipient through an access protocol like POP or IMAP. These protocols do not support the progressive delivery of messages as they are arriving. However, by making modifications to these access protocols, a message may be progressively delivered to a recipient as the media of the message is arriving over the network. Such modifications include the removal of the current requirement that the email server know the full size of the email message before the message can be downloaded to the client. By removing this restriction, a client may begin downloading the time-based media of an email message as the time-based media of the email message is received at the server over the network. 
     Referring to  FIG. 8 , the structure of a conventional email  120  according to the prior art is illustrated. The email  120  includes a header  122  and a body  124 . The header includes a “To” (or possibly the CC and/or BCC fields) field, a “From” field, a unique global ID number, a subject field, optional attachments, and a date/time stamp. The body  124  of the email includes the media to be transmitted, which typically includes a typed message and possibly attached files (e.g. documents or photos). When complete, the email is transmitted by implementing a “send” function or command A DNS lookup of the email address of the recipient is then performed and the email is routed to the recipient. Conventional emails are “static”, meaning the body of the email, including attachments, must be created before transmission may begin. Once transmission starts, the contents defined in the body is fixed, and cannot be dynamically altered or updated. As a result, there is no way to progressively transmit with conventional emails time-based media as the media is being created. Prior art emails  120  are therefore incapable of supporting near real-time communication. 
     Referring to  FIG. 9 , one possible embodiment of a “progressive” email  130  according to the principles of the invention is shown. The email message  130 , which is capable of supporting real-time communication, includes a header  132  including a “To” field (and possibly CC and/or BCC fields) and a body  134 . The structure of email  130  differs from a conventional prior art email  120  in at least two regards. First, the header  132  includes an email Start date/time and an End date/time. By associating a start and end time with an email  130 , as opposed to just a date/time stamp when an email  120  is sent, the second difference may be realized. As soon as the email address of the recipient is defined, the delivery path to the next hop or hops is immediately ascertained, using a DNS lookup result of the defined email address. Again, the lookup result can be either an actual or a previous result that is cached. As the delivery route from hop to hop is discovered, time-based media may be progressively transmitted as it is created, using the streaming nature of SMTP, Microsoft Exchange or any other type of email protocol. The body  134  of email  130  is therefore “progressive”. As the time-based media associated with an email message  130  is dynamically created, the time-based media is progressively transmitted to the email server of the recipient. If an email  130  is sent to multiple recipients, regardless if identified in the To, CC or BCC fields, the above process is repeated for each. 
     With progressive emails  130 , an email protocol session is established with the email server associated with the sender as soon as the email address of the recipient is defined. This differs from conventional emails  120 , where the email protocol session is typically initiated only after the email has been composed in full and the sender implements the “send” function. As a result, the delivery route can be discovered either before or concurrent with the progressive transmission of time-based media as it is being created. In situations where the time-based media may be created before the session is established, the time-based media may be temporarily and/or persistently stored as the media is created. The stored media may then be progressively transmitted from storage once the protocol session with the email server is established. 
     The End date/time of email  130  may be either defined or open-ended. When the sender actively implements the end function  38 / 56  on the communication device  14 , then the end time of the email  130  is defined. If the end function  38 / 56  is never implemented, then the duration of the email  130  is “open-ended” and does not necessarily have a defined end date/time. Open-ended emails  130  are therefore typically terminated by default after a predetermined period of time where no media is created. 
     In summary, progressive emails  130  can be sent using SMTP, Microsoft Exchange or any other proprietary or non-proprietary email protocol by implementing the above-described modifications. Similarly, recipients may simultaneously and progressively review the time-based media of progressive emails  130  by modifying access protocols such as POP, IMAC and the like. Together, these modifications enable the use of email addressing, email protocols, DNS and DNS protocols, and the existing email infrastructure to support real-time communication of time-based media. 
     IV. Late Binding of Recipient Addresses for Real-Time Voice and Other Time-Based Media 
     With the messages (as described with regard to  FIGS. 4A, 4B and 5A-5D ) or progressive emails  130  described above, a user addresses a recipient using their globally addressable email address and then immediately begins talking or generating time-based media. With each embodiment, the delivery route is immediately discovered as soon as the email address of the recipient is defined. Time-based media is progressively transmitted along the delivery route as it is discovered as the media is created. Consequently the discovery of an active delivery route and the progressive creation, transmission and delivery of the time-based media may occur in real-time. In the event the actual delivery route is discovered after the creation of time-based media has started, then the media may be temporarily and/or persistently stored and then transmitted from storage once the active delivery route is defined. No network connection or circuit needs to be established before the sender may start talking or creating other media. The ability to progressively and simultaneously transmit the time-based media using DNS and the infrastructure of email therefore enables the late binding of recipient addresses for voice and other time-based media in a manner that previously was not possible. 
     V. Conversations 
     The messaging methods and systems as described (with regard to  FIGS. 1-3, 4A-4B, 5A-5D  or  FIG. 9 ) are each conducive for supporting conversations between sending and receiving users. When two or more parties are conversing back and forth using any of the above-listed RVX protocols or progressive emails  130 , then the conversation may take place (i) in the near real-time mode; (ii) the time-shifted mode; or (iii) seamlessly transition between the two modes. When two or more participants are conversing in the real-time mode, the user experience is similar to a conventional full duplex telephone conversation. In the time-shifted mode, the user experience is similar to an asynchronous messaging system. As described in more detail in the above-mentioned U.S. applications, the media may be rendered using a number of different rendering options, such as play, catch up to live, pause a live conversation, jump to the head of a conversation, jump to a previous point in time of the conversation, render faster, render slower, jump between different conversations, etc. By using certain rendering options, a user may seamlessly transition a conversation from the time-shifted mode to the real-time mode and vice versa. 
     Regardless of the embodiment, the “reply” function may be implemented in a variety ways. For example, the recipient may enter an explicit reply command into their communication device  14 , such as by using a predefined voice or keystroke command, or entering a command through a touch screen. Alternatively, a reply message or email may be generated automatically when the recipient begins speaking or generating other time-based media in response to a message or email  130 . When a reply message is automatically created, the email address of the original sender is used for addressing the reply message. 
     In yet other embodiments, the RVX protocol used for sending and receiving the messages of a conversation between participants in the real-time mode do not necessarily have to be the same. For example, one participant may send messages using one of the CTP, synchronization, progressive emails  130 , VoIP, SIP, RTP, or Skype protocols, whereas other participants may use a different one of the listed protocols, provided some type of a common conversation identifier is used. Any messages, regardless of the protocol used for transmission, are linked or threaded together using the unique conversation identifier. 
     In various further embodiments, conversations can be defined using a variety of criteria. For example, conversations may be defined by the name of a person (e.g., mom, spouse, boss, etc) or common group of people (e.g., basketball team, sales team, poker buddies, etc). Conversations may also be defined by topic, such as fantasy football league, ACME corporate account, or “skunk works” project. Regardless of the contextual attribute used to define a conversation, the ability to link or organize the messages of a particular conversation together creates the notion of a persistent or ongoing conversation. With a conventional telephone call, the conversation typically ends when the parties hang up. There is no way to contextually link, organize and possibly store the spoken words of multiple telephone exchanges between the same parties. On the contrary, conversations, as defined herein, are a set of common messages linked together by a common attribute. So long as messages are added to the conversation, the conversation is continuous or ongoing. This attribute makes it possible for a participant to contribute to a conversation at any arbitrary time. For example, a user may select a conversation among a list of conversations and contribute a message to the selected conversation at anytime. The message is then sent to all the conversation participants. Messages are therefore not necessarily sent when either a conversation is first created or in reply to an incoming message. 
     VI. Implementation Embodiments 
     The messaging methods as described with regard to  FIGS. 1-3, 4A-4B and 5A-5D  and progressive emails  130  may be implemented in a variety of ways. For example, cell phone and other mobile communication service providers may provide users with peer-to-peer mobile communication devices that operate using either messages and/or progressive emails  130 . In addition, these service providers may also maintain a network  12  of servers  16  for conveying messages between users as described herein using one or more RVX protocols. 
     In yet another embodiment, the messaging and progressive email  130  methods may be embedded in a software application that is intended to be loaded into and executed on conventional telephones, mobile or cellular telephones and radios, mobile, desktop and laptop computers. In each of these cases, the application enables the device to send, receive and process messages and progressive emails  130  as described herein. 
     In yet other implementations, conventional email clients can be modified to create, receive and process progressive emails  130 . The modified email client may alternatively reside on a server on the Internet or other proprietary or non-proprietary network, on sending or receiving devices, or both. 
     Although the above-described systems and methods were generally described in the context of a single sender and a single recipient (as discussed with regard to  FIGS. 4A-4B and 5A-5D ) or emails  130  to a single recipient, it should be understood the messages and/or emails  130  might be simultaneously sent to multiple parties. Each recipient will either receive or not receive the message or email, depending on their status, as described above. 
     Also although the above-described email methods were generally described in the context of “globally” unique identifiers, such as an email address, it is necessary to note that such identifiers do not necessarily have to be a global. In alternative embodiments, the identifier may uniquely identify a user within a defined non-global community of users. For example, a community, such a social networking website, may issue each user a unique identifier within the community. Users within the community can then communicate with one another, as described herein with regard to  FIGS. 1 through 10 . The unique identifier assigned to each user is used to not only authenticate each user, but also for routing messages and media between users. Accordingly the term “identifier” as used in this application is intended to be broadly construed and mean both globally and non-globally unique identifiers. 
     It also should be noted that the system and methods as described herein are not intended for use with only “live” real-time transmission. The aforementioned systems and methods as described with respect to  FIGS. 1 through 3, 4A-4B, 5A-5D and 9  may also be used with the real-time transmission of previously created and stored time-based media. As the media is retrieved from storage, it is progressively transmitted as the delivery route to the recipient is discovered, as described in detail above. 
     The time-based media exchanged by the messages and/or emails is not limited to just voice or video. In addition, the time-based media may be delivered to a recipient in a different form than it was created. For example, a voice message may be transcribed into a text file or a message in English may be translated into another language before being delivered to the recipient. Any media that varies over time, such as sensor data, GPS or positional information, may also be transmitted. 
     While the invention has been particularly shown and described with reference to specific embodiments thereof, it will be understood by those skilled in the art that changes in the form and details of the disclosed embodiments may be made without departing from the spirit or scope of the invention. It is therefore intended that the invention be interpreted to include all variations and equivalents that fall within the true spirit and scope of the invention, as provided in the attached claims.