Patent Publication Number: US-9432412-B2

Title: System and method for routing and communicating in a heterogeneous network environment

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 12/852,112, filed. Aug. 6, 2010, and entitled SYSTEM AND METHOD FOR ROUTING AND COMMUNICATING IN A HETEROGENEOUS NETWORK ENVIRONMENT, which application is a divisional of U.S. patent Ser. No. 11/252,262, filed Oct. 17, 2005, now U.S. Pat. No. 7,933,260, and entitled SYSTEM AND METHOD FOR ROUTING AND COMMUNICATING IN A HETEROGENEOUS NETWORK ENVIRONMENT, which is a continuation-in-part of U.S. patent application Ser. No. 11/081,068, filed on Mar. 15, 2005, now U.S. Pat. No. 7,656,870, issued on Feb. 2, 2010, which application Ser. No. 11/081,068 claims benefit of U.S. Provisional Patent Ser. No. 60/583,536, filed Jun. 29, 2004, 60/628,183, filed Nov. 15, 2004, and 60/628,291, filed Nov. 17, 2004, all of which are incorporated by reference in the present application. 
    
    
     BACKGROUND 
     Current packet-based communication networks may be generally divided into peer-to-peer networks and client/server networks. Traditional peer-to-peer networks support direct communication between various endpoints without the use of an intermediary device (e.g., a host or server). Each endpoint may initiate requests directly to other endpoints and respond to requests from other endpoints using credential and address information stored on each endpoint. However, because traditional peer-to-peer networks include the distribution and storage of endpoint information (e.g., addresses and credentials) throughout the network on the various insecure endpoints, such networks inherently have an increased security risk. While a client/server model addresses the security problem inherent in the peer-to-peer model by localizing the storage of credentials and address information on a server, a disadvantage of client/server networks is that the server may be unable to adequately support the number of clients that are attempting to communicate with it. As all communications (even between two clients) must pass through the server, the server can rapidly become a bottleneck in the system. 
     Accordingly, what is needed are a system and method that addresses these issues. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a simplified network diagram of one embodiment of a hybrid peer-to-peer system. 
         FIG. 2 a    illustrates one embodiment of an access server architecture that may be used within the system of  FIG. 1 . 
         FIG. 2 b    illustrates one embodiment of an endpoint architecture that may be used within the system of  FIG. 1 . 
         FIG. 2 c    illustrates one embodiment of components within the endpoint architecture of  FIG. 2 b    that may be used for cellular network connectivity. 
         FIG. 2 d    illustrates a traditional softswitch configuration with two endpoints. 
         FIG. 2 e    illustrates a traditional softswitch configuration with three endpoints and a media bridge. 
         FIG. 2 f    illustrates one embodiment of the present disclosure with two endpoints, each of which includes a softswitch. 
         FIG. 2 g    illustrates one embodiment of the present disclosure with three endpoints, each of which includes a softswitch. 
         FIG. 3 a    is a sequence diagram illustrating the interaction of various components of  FIG. 2 b    when placing a call. 
         FIG. 3 b    is a sequence diagram illustrating the interaction of various components of  FIG. 2 b    when receiving a call. 
         FIG. 4  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may be authenticated and communicate with another endpoint. 
         FIG. 5  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may determine the status of another endpoint. 
         FIG. 6  is a sequence diagram illustrating an exemplary process by which an access server of  FIG. 1  may aid an endpoint in establishing communications with another endpoint. 
         FIG. 7  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may request that it be added to the buddy list of another endpoint that is currently online. 
         FIG. 8  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may request that it be added to the buddy list of another endpoint that is currently offline. 
         FIG. 9  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may request that it be added to the buddy list of another endpoint that is currently offline before it too goes offline. 
         FIG. 10  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may send a voicemail to another endpoint that is online. 
         FIG. 11  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 1  may send a voicemail to another endpoint that is offline. 
         FIG. 12  is a simplified diagram of another embodiment of a peer-to-peer system that is coupled to destinations outside of the peer-to-peer system. 
         FIG. 13  is a sequence diagram illustrating an exemplary process by which an endpoint of  FIG. 12  may directly contact a destination outside of the peer-to-peer system. 
         FIG. 14  is a flowchart of one embodiment of a method by which a routing table may be downloaded and utilized by an endpoint. 
         FIG. 15  is a sequence diagram illustrating an exemplary process by which an external device may establish contact with an endpoint within the peer-to-peer system of  FIG. 12 . 
         FIG. 16  is a flowchart of one embodiment of a method by which an endpoint may provide interactive voice response functionality. 
         FIG. 17  is a flowchart of one embodiment of a method by which wiretap functionality may be provided on an endpoint. 
         FIG. 18  is a sequence diagram illustrating an exemplary process by which an endpoint may stream data to one or more other endpoints. 
         FIG. 19  is a sequence diagram illustrating an exemplary process by which an endpoint may conduct a private transaction with one or more buddy endpoints. 
         FIG. 20  is a sequence diagram illustrating an exemplary process by which an endpoint may conduct a public transaction with one or more other endpoints. 
         FIG. 21  is a sequence diagram illustrating an exemplary process by which an endpoint may establish a conference call with other endpoints. 
         FIG. 22  is a simplified diagram of an embodiment of a peer-to-peer system that is coupled to destinations outside of the peer-to-peer system. 
         FIG. 23  is a flowchart of one embodiment of a method by which an endpoint within the system of  FIG. 22  can determine a route to communicate with another endpoint. 
         FIG. 24  is a simplified diagram of another embodiment of a peer-to-peer system that is coupled to destinations outside of the peer-to-peer system. 
         FIG. 25  is a flowchart of one embodiment of a method by which a media router can facilitate communications between endpoints within the system of  FIG. 24 . 
     
    
    
     DETAILED DESCRIPTION 
     The present disclosure is directed to a system and method for peer-to-peer hybrid communications. It is understood that the following disclosure provides many different embodiments or examples. Specific examples of components and arrangements are described below to simplify the present disclosure. These are, of course, merely examples and are not intended to be limiting. In addition, the present disclosure may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. 
     Referring to  FIG. 1 , one embodiment of a peer-to-peer hybrid system  100  is illustrated. The system  100  includes an access server  102  that is coupled to endpoints  104  and  106  via a packet network  108 . Communication between the access server  102 , endpoint  104 , and endpoint  106  is accomplished using predefined and publicly available (i.e., non-proprietary) communication standards or protocols (e.g., those defined by the Internet Engineering Task Force (IETF) or the International Telecommunications Union-Telecommunications Standard Sector (ITU-T)). For example, signaling communications (e.g., session setup, management, and teardown) may use a protocol such as the Session Initiation Protocol (SIP), while actual data traffic may be communicated using a protocol such as the Real-time Transport Protocol (RIP). As will be seen in the following examples, the use of standard protocols for communication enables the endpoints  104  and  106  to communicate with any device that uses the same standards. The communications may include, but are not limited to, voice calls, instant messages, audio and video, mails, and any other type of resource transfer, where a resource represents any digital data. In the following description, media traffic is generally based on the user datagram protocol (UDP), while authentication is based on the transmission control protocol/internet protocol (TCP/IP). However, it is understood that these are used for purposes of example and that other protocols may be used in addition to or instead of UDP and TCP/IP. 
     Connections between the access server  102 , endpoint  104 , and endpoint  106  may include wireline and/or wireless communication channels. In the following description, it is understood that the term “direct” means that there is no endpoint or access server in the communication channel(s) between the endpoints  104  and  106 , or between either endpoint and the access server. Accordingly, the access server  102 , endpoint  104 , and endpoint  106  are directly connected even if other devices (e.g., routers, firewalls, and other network elements) are positioned between them. In addition, connections to endpoints, locations, or services may be subscription based, with an endpoint only having access if the endpoint has a current subscription. Furthermore, the following description may use the terms “user” and “endpoint” interchangeably, although it is understood that a user may be using any of a plurality of endpoints. Accordingly, if an endpoint logs in to the network, it is understood that the user is logging in via the endpoint and that the endpoint represents the user on the network using the user&#39;s identity. 
     The access server  102  stores profile information for a user, a session table to track what users are currently online, and a routing table that matches the address of an endpoint to each online user. The profile information includes a “buddy list” for each user that identifies other users (“buddies”) that have previously agreed to communicate with the user. Online users on the buddy list will show up when a user logs in, and buddies who log in later will directly notify the user that they are online (as described with respect to  FIG. 4 ). The access server  102  provides the relevant profile information and routing table to each of the endpoints  104  and  106  so that the endpoints can communicate directly with one another. Accordingly, in the present embodiment, one function of the access server  102  is to serve as a storage location for information needed by an endpoint in order to communicate with other endpoints and as a temporary storage location for requests, voicemails, etc., as will be described later in greater detail. 
     With additional reference to  FIG. 2 a   , one embodiment of an architecture  200  for the access server  102  of  FIG. 1  is illustrated. The architecture  200  includes functionality that may be provided by hardware and/or software, and that may be combined, into a single hardware platform or distributed among multiple hardware platforms. For purposes of illustration, the access server in the following examples is described as a single device, but it is understood that the term applies equally to any type of environment (including a distributed environment) in which at least a portion of the functionality attributed to the access server is present. 
     In the present example, the architecture includes web services  202  (e.g., based on functionality provided by XML, SOAP, .NET, MONO), web server  204  (using, for example, Apache or IIS), and database  206  (using, for example, mySQL or SQLServer) for storing and retrieving routing tables  208 , profiles  210 , and one or more session tables  212 . Functionality for a STUN (Simple Traversal of UDP through NATs (Network Address Translation)) server  214  is also present in the architecture  200 . As is known, STUN is a protocol for assisting devices that are behind a NAT firewall or router with their packet routing. The architecture  200  may also include a redirect server  216  for handling requests originating outside of the system  100 . One or both of the STUN server  214  and redirect server  216  may be incorporated into the access server  102  or may be a standalone device. In the present embodiment, both the server  204  and the redirect server  216  are coupled to the database  206 . 
     Referring to  FIG. 2 b   , one embodiment of an architecture  250  for the endpoint  104  (which may be similar or identical to the endpoint  106 ) of  FIG. 1  is illustrated. It is understood that that term “endpoint” may refer to many different devices having some or all of the described functionality, including a computer, a VoIP telephone, a personal digital assistant, a cellular phone, or any other device having an IP stack upon which the needed protocols may be run. The architecture  250  includes an endpoint engine  252  positioned between a graphical user interface (GUI)  254  and an operating system  256 . The GUI  254  provides user access to the endpoint engine  252 , while the operating system  256  provides underlying functionality, as is known to those of skill in the art. 
     The endpoint engine  252  may include multiple components and layers that support the functionality required to perform the operations of the endpoint  104 . For example, the endpoint engine  252  includes a softswitch  258 , a management layer  260 , an encryption/decryption module  262 , a feature layer  264 , a protocol layer  266 , a speech-to-text engine  268 , a text-to-speech engine  270 , a language conversion engine  272 , an out-of-network connectivity module  274 , a connection from other networks module  276 , a p-commerce (e.g., peer commerce) engine  278  that includes a p-commerce agent and a p-commerce broker, and a cellular network interface module  280 . 
     Each of these components/layers may be further divided into multiple modules. For example, the softswitch  258  includes a call control module, an instant messaging (IM) control module, a resource control module, a CALEA (Communications Assistance to Law Enforcement Act) agent, a media control module, a peer control module, a signaling agent, a fax control module, and a routing module. 
     The management layer  260  includes modules for presence (i.e., network presence), peer management (detecting peers and notifying peers of being online), firewall management (navigation and management), media management, resource management, profile management, authentication, roaming, fax management, and media playback/recording management. 
     The encryption/decryption module  262  provides encryption for outgoing packets and decryption for incoming packets. In the present example, the encryption/decryption module  262  provides application level encryption at the source, rather than at the network. However, it is understood that the encryption/decryption module  262  may provide encryption at the network in some embodiments. 
     The feature layer  264  provides support for various features such as voice, video, IM, data, voicemail, file transfer, file sharing, class 5 features, short message service (SMS), interactive voice response (IVR), faxes, and other resources. The protocol layer  266  includes protocols supported by the endpoint, including SIP, HTTP, HTTPS, STUN, RTP, SRTP, and ICMP. It is understood that these are examples only, and that fewer or more protocols may be supported. 
     The speech-to-text engine  268  converts speech received by the endpoint (e.g., via a microphone or network) into text, the text-to-speech engine  270  converts text received by the endpoint into speech (e.g., for output via a speaker), and the language conversion engine  272  may be configured to convert inbound or outbound information (text or speech) from one language to another language. The out-of-network connectivity module  274  may be used to handle connections between the endpoint and external devices (as described, with respect to  FIG. 12 ), and the connection from other networks module  276  handles incoming connection attempts from external devices. The cellular network interface module  280  may be used to interact with a wireless network. 
     With additional reference to  FIG. 2 c   , the cellular network interface module  280  is illustrated in greater detail. Although not shown in  FIG. 21 ), the softswitch  258  of the endpoint architecture  250  includes a cellular network interface for communication with the cellular network interface module  280 . In addition, the cellular network interface module  280  includes various components such as a call control module, a signaling agent, a media manager, a protocol stack, and a device interface. It is noted that these components may correspond to layers within the endpoint architecture  250  and may be incorporated directly into the endpoint architecture in some embodiments. 
     Referring to  FIG. 2 d   , a traditional softswitch architecture is illustrated with two endpoints  282  and  284 , neither of which includes a softswitch, in the present example, an external softswitch  286  maintains a first signaling leg (dotted line) with the endpoint  282  and a second signaling leg (dotted line) with the endpoint  284 . The softswitch  286  links the two legs to pass signaling information between the endpoints  282  and  284 . Media traffic (solid lines) may be transferred between the endpoints  282  and  284  via a media gateway  287 . 
     With additional reference to  FIG. 2 e   , the traditional softswitch architecture of  FIG. 2 d    is illustrated with a third endpoint  288  that also does not include a softswitch. The external softswitch  286  now maintains a third signaling leg (dotted line) with the endpoint  288 . In the present example, a conference call is underway. However, as none of the endpoints includes a softswitch, a media bridge  290  connected to each endpoint is needed for media traffic. Accordingly, each endpoint has at most two concurrent connections one with the softswitch for signaling and another with the media bridge for media traffic. 
     Referring to  FIG. 2 f   , in one embodiment, unlike the traditional architecture of  FIGS. 2 d  and 2 e   , two endpoints (e.g., the endpoints  104  and  106  of  FIG. 1 ) each include a softswitch (e.g., the softswitch  258  of  FIG. 2 b   ). Each endpoint is able to establish and maintain both signaling and media traffic connections (both virtual and physical legs) with the other endpoint. Accordingly, no external softswitch is needed, as this model uses a distributed softswitch method to handle communications directly between the endpoints. 
     With additional reference to  FIG. 2 g   , the endpoints  104  and  106  are illustrated with another endpoint  292  that also contains a softswitch. In this example, a conference call is underway with the endpoint  104  acting as the host. To accomplish this, the softswitch contained in the endpoint  104  enables the endpoint  104  to support direct signaling and media traffic connections with the endpoint  292 . The endpoint  104  can then forward media traffic from the endpoint  106  to the endpoint  292  and vice versa. Accordingly, the endpoint  104  may support multiple connections to multiple endpoints and, as in  FIG. 2 f   , no external softswitch is needed. 
     Referring again to  FIG. 2 b   , in operation, the softswitch  258  uses functionality provided by underlying layers to handle connections with other endpoints and the access server  102 , and to handle services needed by the endpoint  104 . For example, as is described below in greater detail with respect to  FIGS. 3 a  and 3 b   , incoming and outgoing calls may utilize multiple components within the endpoint architecture  250 . 
     Referring to  FIG. 3 a   , a sequence diagram  300  illustrates an exemplary process by which the endpoint  104  may initiate a call to the endpoint  106  using various components of the architecture  250 . Prior to step  302 , a user (not shown) initiates a call via the GUI  254 . In step  302 , the GUI  254  passes a message to the call control module (of the softswitch  258 ) to make the call. The call control module contacts the peer control module (softswitch  258 ) in step  304 , which detects the peer (if not already done), goes to the routing table (softswitch  258 ) for the routing information, and performs similar operations, it is understood that not all interactions are illustrated. For example, the peer control module may utilize the peer management module (of the management layer  260 ) for the peer detection. The call control module then identifies a route for the call in step  306 , and sends message to the SIP protocol layer (of the protocol layer  266 ) to make the call in step  308 . In step  310 , the outbound message is encrypted (using the encryption/decryption module  262 ) and the message is sent to the network via the OS  256  in step  312 . 
     After the message is sent and prior to receiving a response, the call control module instructs the media control module (softswitch  258 ) to establish the needed near-end media in step  314 . The media control module passes the instruction to the media manager (of the management layer  260 ) in step  316 , which handles the establishment of the near-end media. 
     With additional reference to  FIG. 3 b   , the message sent by the endpoint  104  in step  312  ( FIG. 3 a   ) is received by the endpoint  106  and passed from the OS to the SIP protocol layer in step  352 . The message is decrypted in step  354  and the call is offered to the call control module in step  356 . The call control module notifies the GUI of an incoming call in step  358  and the GUI receives input identifying whether the call is accepted or rejected (e.g., by a user) in step  360 . In the present example, the call is accepted and the GUI passes the acceptance to the call control module in step  362 . The call control module contacts the peer control module in step  364 , which identifies a route to the calling endpoint and returns the route to the call control module in step  366 . In steps  368  and  370 , the call control module informs the SIP protocol layer that the call has been accepted and the message is encrypted using the encryption/decryption module. The acceptance message is then sent to the network via the OS in step  372 . 
     In the present example, after the call control module passes the acceptance message to the SIP protocol layer, other steps may occur to prepare the endpoint  106  for the call. For example, the call control module instructs the media control module to establish near-end media in step  374 , and the media control module instructs the media manager to start listening to incoming media in step  376 . The call control module also instructs the media control module to establish far-end media (step  378 ), and the media control module instructs the media manager to start transmitting audio in step  380 . 
     Returning to  FIG. 3 a   , the message sent by the endpoint  106  (step  372 ) is received by the OS and passed on to the SIP protocol layer in step  318  and decrypted in step  320 . The message (indicating that the call has been accepted) is passed to the call control module in step  322  and from there to the GUI in step  324 . The call control module then instructs the media control module to establish far-end media in step  326 , and the media control module instructs the media manager to start transmitting audio in step  328 . 
     The following figures are sequence diagrams that illustrate various exemplary functions and operations by which the access server  102  and the endpoints  104  and  106  may communicate. It is understood that these diagrams are not exhaustive and that various steps may be excluded from the diagrams to clarify the aspect being described. 
     Referring to  FIG. 4  and using the endpoint  104  as an example), a sequence diagram  400  illustrates an exemplary process by which the endpoint  104  may authenticate with the access server  102  and then communicate with the endpoint  106 . As will be described, after authentication, all communication (both signaling and media traffic) between the endpoints  104  and  106  occurs directly without any intervention by the access server  102 . In the present example, it is understood that neither endpoint is online at the beginning of the sequence, and that the endpoints  104  and  106  are “buddies.” As described above, buddies are endpoints that have both previously agreed to communicate with one another. 
     In step  402 , the endpoint  104  sends a registration and/or authentication request message to the access server  102 . If the endpoint  104  is not registered with the access server  102 , the access server will receive the registration request (e.g., user ID, password, and email address) and will create a profile for the endpoint (not shown). The user ID and password will then be used to authenticate the endpoint  104  during later logins. It is understood that the user ID and password may enable the user to authenticate from any endpoint, rather than only the endpoint  104 . 
     Upon authentication, the access server  102  updates a session table residing on the server to indicate that the user ID currently associated with the endpoint  104  is online. The access server  102  also retrieves a buddy list associated with the user ID currently used by the endpoint  104  and identifies which of the buddies (if any) are online using the session table. As the endpoint  106  is currently offline, the buddy list will reflect this status. The access server  102  then sends the profile information (e.g., the buddy list) and a routing table to the endpoint  104  in step  404 . The routing table contains address information for online members of the buddy list. It is understood that steps  402  and  401  represent a make and break connection that is broken after the endpoint  104  receives the profile information and routing table. 
     In steps  406  and  408 , the endpoint  106  and access server  102  repeat steps  402  and  404  as described for the endpoint  104 . However, because the endpoint  104  is online when the endpoint  106  is authenticated, the profile information sent to the endpoint  106  will reflect the online status of the endpoint  104  and the routing table will identify how to directly contact it. Accordingly, in step  410 , the endpoint  106  sends a message directly to the endpoint  104  to notify the endpoint  104  that the endpoint  106  is now online. This also provides the endpoint  104  with the address information needed to communicate directly with the endpoint  106 . In step  412 , one or more communication sessions may be established directly between the endpoints  104  and  106 . 
     Referring to  FIG. 5 , a sequence diagram  500  illustrates an exemplary process by Which authentication of an endpoint (e.g., the endpoint  104 ) may occur, in addition, after authentication, the endpoint  104  may determine whether it can communicate with the endpoint  106 . In the present example, the endpoint  106  is online when the sequence begins. 
     In step  502 , the endpoint  104  sends a request to the STUN server  214  of  FIG. 2 . As is known, the STUN server determines an outbound IP address (e.g., the external address of a device (i.e., a firewall, router, etc.) behind which the endpoint  104  is located), an external port, and a type of NAT used by the device. The type of NAT may be, for example, full cane, restricted cone, port restricted cone, or symmetric. As these are known in the art, they will not be described herein in greater detail. The STUN server  214  sends a STUN response back to the endpoint  104  in step  504  with the collected information about the endpoint  104 . 
     In step  506 , the endpoint  104  sends an authentication request to the access server  102 . The request contains the information about endpoint  104  received from the STUN server  214 . In step  508 , the access server  102  responds to the request by sending the relevant profile and routing table to the endpoint  104 . The profile contains the external IP address, port, and NAT type for each of the buddies that are online. 
     In step  510 , the endpoint  104  sends a message to notify the endpoint  106  of its online status (as the endpoint  106  is already online) and, in step  512 , the endpoint  104  waits for a response. After the expiration of a timeout period within which no response is received from the endpoint  106 , the endpoint  104  will change the status of the endpoint  106  from “online” (as indicated by the downloaded profile information) to “unreachable.” The status of a buddy may be indicated on a visual buddy list by the color of an icon associated with each buddy. For example, when logging in, online buddies may be denoted by a blue icon and offline buddies may be denoted by a red icon. If a response to a notify message is received for a buddy, the icon representing that buddy may be changed from blue to green to denote the buddy&#39;s online status. If no response is received, the icon remains blue to indicate that the buddy is unreachable. Although not shown, a message sent from the endpoint  106  and received by the endpoint  104  after step  514  would indicate that the endpoint  106  is now reachable and would cause the endpoint  104  to change the status of the endpoint  106  to online. Similarly, if the endpoint  104  later sends a message to the endpoint  106  and receives a response, then the endpoint  104  would change the status of the endpoint  106  to online. 
     It is understood that other embodiments may implement alternate NAT traversal techniques. For example, a single payload technique may be used in which TCP/IP packets are used to traverse a UDP restricted firewall or router. Another example includes the use of a double payload in which a UDP packet is inserted into a TCP/IP packet. Furthermore, it is understood that protocols other than STUN may be used. For example, protocols such as Internet Connectivity Establishment (ICE) or Traversal Using Relay NAT (TURN) may be used. 
     Referring to  FIG. 6 , a sequence diagram  600  illustrates an exemplary process by Which the access server  102  may aid the endpoint  104  in establishing communications with the endpoint  106  (which is a buddy). After rendering aid, the access server  102  is no longer involved and the endpoints may communicate directly. In the present example, the endpoint  106  is behind a NAT device that will only let a message in (towards the endpoint  106 ) if the endpoint  106  has sent a message out. Unless this process is bypassed, the endpoint  104  will be unable to connect to the endpoint  106 . For example, the endpoint  104  will be unable to notify the endpoint  106  that it is now online. 
     In step  602 , the endpoint  106  sends a request to the STUN server  214  of  FIG. 2 . As described previously, the STUN server determines an outbound IP address, an external port, and a type of NAT for the endpoint  106 . The STUN server  214  sends a STUN response back to the endpoint  106  in step  604  with the collected information about the endpoint  106 . In step  606 , the endpoint  106  sends an authentication request to the access server  102 . The request contains the information about endpoint  106  received from the STUN server  214 . In step  608 , the access server  102  responds to the request by sending the relevant profile and routing table to the endpoint  106 . In the present example, the access server  102  identifies the NAT type associated with the endpoint  106  as being a type that requires an outbound packet to be sent before an inbound packet is allowed to enter. Accordingly, the access server  102  instructs the endpoint  106  to send periodic messages to the access server  102  to establish and maintain a pinhole through the NAT device. For example, the endpoint  106  may send a message prior to the timeout period of the NAT device in order to reset the timeout period. In this manner, the pinhole may be kept open indefinitely. 
     In steps  612  and  614 , the endpoint  104  sends a STUN request to the STUN server  214  and the STUN server responds as previously described. In step  616 , the endpoint  104  sends an authentication request to the access server  102 . The access server  102  retrieves the buddy list for the endpoint  104  and identifies the endpoint  106  as being associated with a NAT type that will block communications from the endpoint  104 . Accordingly, in step  618 , the access server  102  sends an assist message to the endpoint  106 . The assist message instructs the endpoint  106  to send a message to the endpoint  104 , which opens a pinhole in the NAT device for the endpoint  104 . For security purposes, as the access server  102  has the STUN information for the endpoint  104 , the pinhole opened by the endpoint  106  may be specifically limited to the endpoint associated with the STUN information. Furthermore, the access server  102  may not request such a pinhole for an endpoint that is not on the buddy list of the endpoint  106 . 
     The access server  104  sends the profile and routing table to the endpoint  104  in step  620 , in step  622 , the endpoint  106  sends a message (e.g., a ping packet) to the endpoint  104 . The endpoint  104  may then respond to the message and notify the endpoint  106  that it is now online. If the endpoint  106  does not receive a reply from the endpoint  104  within a predefined period of time, it may close the pinhole (which may occur simply by not sending another message and letting the pinhole time out). Accordingly, the difficulty presented by the NAT device may be overcome using the assist message, and communications between the two endpoints may then occur without intervention by the access server  102 . 
     Referring to  FIG. 7 , a sequence diagram  700  illustrates an exemplary process by which the endpoint  106  may request that it be added to the endpoint  104 &#39;s buddy list. In the present example, the endpoints  104  and  106  both remain online during the entire process. 
     In step  702 , the endpoint  104  sends a registration and/or authentication request message to the access server  102  as described previously. Upon authentication, the access server  102  updates a session table residing on the server to indicate that the user ID currently associated with the endpoint  104  is online. The access server  102  also retrieves a buddy list associated with the user ID currently used by the endpoint  104  and identifies which of the buddies (if any) are online using the session table. As the endpoint  106  is not currently on the buddy list, it will not be present. The access server  102  then sends the profile information and a routing table to the endpoint  104  in step  704 . 
     In steps  706  and  708 , the endpoint  106  and access server  102  repeat steps  702  and  704  as described for the endpoint  104 . The profile information sent by the access server  102  to the endpoint  106  will not include the endpoint  104  because the two endpoints are not buddies. 
     In step  710 , the endpoint  106  sends a message to the access server  102  requesting that the endpoint  104  be added to its buddy list. The access server  102  determines that the endpoint  104  is online (e.g., using the session table) in step  712  and sends the address for the endpoint  104  to the endpoint  106  in step  714 . In step  716 , the endpoint  106  sends a message directly to the endpoint  104  requesting that the endpoint  106  be added to its buddy list. The endpoint  104  responds to the endpoint  106  in step  718  with either permission or a denial, and the endpoint  104  also updates the access server  102  with the response in step  720 . For example, if the response grants permission, then the endpoint  104  informs the access server  102  so that the access server can modify the profile of both endpoints to reflect the new relationship. It is understood that various other actions may be taken. For example, if the endpoint  104  denies the request, then the access server  102  may not respond to another request by the endpoint  106  (with respect to the endpoint  104 ) until a period of time has elapsed. 
     It is understood that many different operations may be performed with respect to a buddy list. For example, buddies may be deleted, blocked/unblocked, buddy status may be updated, and a buddy profile may be updated. For block/unblock, as well as status and profile updates, a message is first sent to the access server  102  by the endpoint requesting the action (e.g., the endpoint  104 ). Following the access server  102  update, the endpoint  104  sends a message to the peer being affected by the action (e.g., the endpoint  106 ). 
     Buddy deletion may be handled as follows. If the user of the endpoint  104  wants to delete a contact on a buddy list currently associated with the online endpoint  106 , the endpoint  104  will first notify the access server  102  that the buddy is being deleted. The access server  102  then updates the profile of both users so that neither buddy list shows the other user as a buddy. Note that, in this instance, a unilateral action by one user will alter the profile of the other user. The endpoint  104  then sends a message directly to the endpoint  106  to remove the buddy (the user of the endpoint  104 ) from the buddy list of the user of endpoint  106  in real time. Accordingly, even though the user is online at endpoint  106 , the user of the endpoint  104  will be removed from the buddy list of the endpoint  106 . 
     Referring to  FIG. 8 , a sequence diagram  800  illustrates an exemplary process by which endpoint  106  may request that it be added to the endpoint  104 &#39;s buddy list. In the present example, the endpoint  104  is not online until after the endpoint  106  has made its request. 
     In step  802 , the endpoint  106  sends a registration and/or authentication request message to the access server  102  as described previously. Upon authentication, the access server  102  updates a session table residing on the server to indicate that the user ID currently associated with the endpoint  106  is online. The access server  102  also retrieves a buddy list associated with the user ID currently used by the endpoint  106  and identifies which of the buddies (if any) are online using the session table. The access server  102  then sends the profile information and a routing table to the endpoint  106  in step  804 . 
     In step  806 , the endpoint  106  sends a message to the access server  102  requesting that the endpoint  104  be added to its buddy list. The access server  102  determines that the endpoint  104  is offline in step  808  and temporarily stores the request message in step  810 . In steps  812  and  814 , the endpoint  104  and access server  102  repeat steps  802  and  804  as described for the endpoint  106 . However, when the access server  102  sends the profile information and routing table to the endpoint  104 , it also sends the request by the endpoint  106  (including address information for the endpoint  106 ). 
     In step  816 , the endpoint  104  responds directly to the endpoint  106  with either permission or a denial. The endpoint  104  then updates the access server  102  with the result of the response in step  818  and also instructs the access server to delete the temporarily stored request. 
     Referring to  FIG. 9 , a sequence diagram  900  illustrates an exemplary process by Which the endpoint  106  may request that it be added to the endpoint  104 &#39;s buddy list. In the present example, the endpoint  104  is not online until after the endpoint  106  has made its request, and the endpoint  106  is not online to receive the response by endpoint  104 . 
     In step  902 , the endpoint  106  sends a registration and/or authentication request message to the access server  102  as described previously. Upon authentication, the access server  102  updates a session table residing on the server to indicate that the user ID currently associated with the endpoint  106  is online. The access server  102  also retrieves a buddy list associated with the user ID currently used by the endpoint  106  and identifies which of the buddies (if any) are online using the session table. The access server  102  then sends the profile information and a routing table to the endpoint  106  in step  904 . 
     In step  906 , the endpoint  106  sends a message to the access server  102  requesting that the endpoint  104  be added to its buddy list. The access server  102  determines that the endpoint  104  is offline in step  908  and temporarily stores the request message in step  910 . In step  912 , the endpoint  106  notifies the access server  102  that it is going offline. 
     In steps  914  and  916 , the endpoint  104  and access server  102  repeat steps  902  and  904  as described for the endpoint  106 . However, when the access server  102  sends the profile information and routing table to the endpoint  104 , it also sends the request by the endpoint  106 . Endpoint  104  sends its response to the access server  102  in step  918  and also instructs the access server to delete the temporarily stored request. After the endpoint  106 &#39;s next authentication process, its profile information will include endpoint  104  as a buddy (assuming the endpoint  104  granted permission). 
     Referring to  FIG. 10 , a sequence diagram  1000  illustrates an exemplary process by which the endpoint  106  may store a voicemail for the endpoint  104 . In the present example, the endpoint  106  is online, but is not available to take the call. 
     In step  1002 , the endpoint  104  sends a call request message to the endpoint  106  requesting that a call be established between the two endpoints. In step  1004 , the endpoint  106  responds with a message indicating that it is busy and cannot take the call. In step  1006 , after recording a voicemail (not shown), the endpoint  104  sends the voicemail to the access server  102 , which temporarily stores the voicemail in step  1008 . The endpoint  104  then sends a message (e.g., a message waiting indicator (MWI)) to the endpoint  106  in step  1010  before sending the voicemail to the endpoint  106  in step  1012 . The endpoint  106  receives the voicemail in step  1014  (e.g., after ending the previous call) and instructs the access server  102  to delete the temporarily stored voicemail in step  1016 . It is understood that the endpoint  106  may perform many different actions with respect to the voicemail, including saving, forwarding, responding, etc. 
     Referring to  FIG. 11 , a sequence diagram  1100  illustrates an exemplary process by which the endpoint  106  may receive a voicemail from the endpoint  104 . In the present example, the endpoint  106  is offline when the voicemail is recorded and sent. In step  1102 , the endpoint  104  determines that the endpoint  106  is offline. As described previously, such a determination may be made based on the fact that the endpoint  106  was not online when the endpoint  104  was authenticated (as indicated by the profile information from the access server  102 ) and has not since logged in (as it would have notified the endpoint  104  as described with respect to  FIG. 4 ). As the endpoint  106  is offline, the endpoint  104  sends a recorded voicemail to the access server  102  in step  1104 , which temporarily stores the voicemail in step  1106 . The endpoint  106  authenticates with the access server  102  in step  1108  as previously described, and the access server sends the endpoint  106  the relevant profile information and routing table in step  1110 . In addition to the information normally sent to the endpoint  106  after authentication, the access server  102  sends a message such as a message waiting indicator to inform the endpoint  106  of the stored voicemail. In steps  1112  and  1114 , the endpoint  106  retrieves the recorded voicemail and instructs the access point  102  to delete the voicemail from the server. 
     Referring to  FIG. 12 , in another embodiment, the system  100  of  FIG. 1  is illustrated as a “home system” that forms part of a larger system  1200 . The home system includes all endpoints that have registered with the access server  102 . In addition to the home system  100 , a number of external (relative to the home system  100 ) devices are illustrated, including an external endpoint  1202  (e.g., a SIP capable such as a SIP telephone, a computer, a personal digital assistant, a household appliance, or an automated control system for a business or residence). Additional external devices include a gateway  1204  and an IPPBX  1206 , both of which are coupled to a PSTN  1208 . The gateway  1204  is also coupled to a cellular network  1210 , which includes an radio access network, core network, and other cellular network components (not shown). In the present example, both the gateway  1204  and the IPPBX  1206  include a non-proprietary interface (e.g., a SIP interface) that enables them to communicate directly with the SIP-based endpoints  104  and  106 . It is understood that various portions of the system  1200  may include wired and/or wireless interfaces and components. 
     The endpoints  104  and  106  that are within the home system  100  are authenticated by the access server  102  using user-supplied credentials (as previously described). Communication may occur directly between the endpoints  104 ,  106  and devices outside of the home system  100  as follows. The access server  102  serves as a routing table repository. As described previously, a routing table contains information needed by the endpoints  104 ,  106  in order to connect to buddies within the home network  100 . In the present example, the routing table (or another routing table) also contains information needed by the endpoints  104 ,  106  in order to connect to the external devices. Connections to external devices, locations, or services may be subscription based, with the routing table for a particular endpoint only having address information for external devices for which the endpoint has a current subscription. For example, the profile associated with the endpoint  104  may have a flag representing whether the endpoint is subscribed to a service such as a PSTN calling plan. 
     Referring to  FIG. 13 , a sequence diagram  1300  illustrates an exemplary process by which the endpoint  104  may directly contact the external endpoint  1202  within the system  1200  of  FIG. 12 . The endpoint  1202  is online and the endpoint  104  has the authority (e.g., a subscription) to contact the endpoint  1202 . Although the present example uses SIP for signaling and RTP for media traffic, it is understood that other protocols may be used. 
     In step  1302 , the endpoint  104  sends an authentication request message to the access server  102  as described previously. After authentication, the access server  102  sends the profile information and a routing table to the endpoint  104  in step  1304 . After the endpoint  104  has been authenticated, the user of the endpoint places a call (e.g., a VoIP call) to the endpoint  1202 . In step  1306 , the endpoint  104  performs digit collection and analysis on the number entered by the user. As endpoint  104  contains both the routing table and a softswitch, the endpoint is able to identify and place the call directly to the endpoint  1202 . 
     In step  1308 , the endpoints  104  and  106  setup the call. For example, the endpoint  104  may sent a SIP INVITE message directly to the endpoint  1202 . The endpoint  104  must provide any credentials required by the endpoint  1202 . The endpoint  1202  responds with a 200 OK message and the endpoint  104  responds with an ACK message. The endpoints  104  and  1202  may then use an RTP session (step  1310 ) for the VoIP call. After the RTP session is complete, call teardown occurs in step  1312 . Accordingly, as described in the previous examples between endpoints in the home system  100 , the endpoint  104  directly contacts the endpoint  1202  (or gateway  1204  or IPPBX  1206 ) without intervention by the access server  102  after downloading the profile and routing table during authentication. 
     Another external endpoint  1212  may be contacted in the same manner as the endpoint  1202 , although the communications will need to be routed through the gateway  1204  and cellular network  1210 . As with the endpoint  1202 , the endpoint  104  may contact the endpoint  1212  directly without intervention from the access server  102 . 
     Referring to  FIG. 14 , a method  1400  illustrates one possible sequence of events for utilizing the routing tables of the access server  102  for external communications. The method begins in step  1402  when an endpoint (e.g., the endpoint  104 ) authenticates with the access server  102 . The endpoint  101  downloads one or more routing tables in step  1404 , depending on such factors as whether the endpoint  104  has a subscription to a relevant service (e.g., whether the endpoint  104  allowed to call outside of the home network). The routing tables are downloaded in a raw data format, and the endpoint  104  processes the raw data in step  1406  to produce optimal routing rules in step  1408 . At this point, the endpoint  104  may use the routing rules to communicate with other endpoints. 
     The routing tables may change on the access server  102 . For example, a new service area or new subscription options may become accessible. However, unless the endpoint  104  logs off and back on, the endpoint will not be aware of these changes. Accordingly, the access server  102  sends a notification in step  1410  that changes have occurred to the routing tables. In step  1412 , the endpoint  104  determines whether a change has occurred with respect to the routing tables on the endpoint. For example, if the endpoint  104  just logged on, it may have the updated routing tables. Alternatively or additionally, the notification may not indicate which routing tables have changed, and the endpoint  104  will need to determine if any of the routing tables that it uses have changed. 
     If the routing tables have changed, the endpoint  104  makes a determination in step  1414  as to whether the change is relatively large or is minor. If the change is large, the method returns to step  1404 , where the routing tables are downloaded. If the changes are minor, the method continues to step  1416 , where the endpoint  104  updates its routing tables (e.g., the endpoint  104  downloads only the changed information). It is understood that some processing may be needed to prepare the new information for insertion into the existing routing rules. 
     If a call to an external device is to be placed (step  1418 ), the endpoint  104  determines whether it has a match in its routing rules in step  1420 . If a match exists, the endpoint  104  uses the routing rules to route the call to an appropriate gateway or endpoint in step  1422 . If no match exists, the endpoint  104  has insufficient information to route the call (step  1424 ) and ends the call process. 
     Referring to  FIG. 15 , a sequence diagram  1500  illustrates an exemplary process by which the external endpoint  1202  may attempt to establish contact with the endpoint  104  within the system  1200  of  FIG. 12  using SIP messaging. In step  1502 , the endpoint  1202  sends a SIP INVITE message to a redirect server the redirect server  216  of  FIG. 2 a   ). The redirect server  216  accesses a database (e.g., the database  206  of  FIG. 2 a   ) in step  1504  and obtains contact information for the endpoint  104 . The information may also include credentials (e.g., a username and password) required by the endpoint  104 . If credentials are required, the redirect server  216  sends a message to the endpoint  1202  in step  1506  requesting the credentials. The endpoint  1202  responds to the credentials request in step  1508  by sending a SIP INVITE containing the credentials to the redirect server  216 . The redirect server  216  then sends a redirect message to the endpoint  1202  with the address information for the endpoint  104  in step  1510 . In step  1512 , the endpoint  1202  may then directly contact the endpoint  104  with a SIP INVITE message. If the endpoint  104  is not available (e.g., offline), the redirect server  216  may send a message to the endpoint  1202  that the endpoint  104  is not available. 
     Referring again to  FIG. 12 , in the present example, the home system  100  includes a resource server  1214 . Although the resource server  1214  may be part of the access server  102 , it is separated into a separate server for purposes of illustration. The access server  102  and resource server  1214  may be in communication with one another (not shown) for purposes of identifying access rights and similar issues. The resource server  1214  stores and distributes various resources to the endpoints  104  and  106 . As described previously, a resource represents any type of digital data. In operation, an endpoint (e.g., the endpoint  104 ) may store a resource on the resource server  1214  for later retrieval by the endpoint  106  or may transfer the resource directly to the endpoint  106 . Furthermore, the resource server  1214  may distribute the resource to the endpoint  106 , as well as to other endpoints. In this manner, the resource server  1214  may serve as temporary or permanent storage. In some embodiments, the resource server  1214  may restrict access based on credentials provided by the endpoints  104  and  106 . For example, if the endpoint  104  only has the credentials for certain resources, then the resource server may limit the endpoints access to those resources. Communication between an endpoint and the resource server occurs directly as described above with respect to two endpoints. 
     It is understood that many different methods may be implemented using the endpoints and/or access server described above. Various methods are described below as examples, but it is understood that many other methods or variations of methods are possible. 
     In one embodiment, a port rotation method may be implemented that allows for changing/rotating the port used to listen for communications to provide added security. The rotation may occur during idle time of the operation of the endpoint. For example, when idle time is detected, a random unused port is selected. The endpoint then informs the access server of the new route information and sends out a peer-to-peer notification to all online buddies to notify them of the change in the port/route information. 
     In another embodiment, wireless calls may be made through an endpoint. For example, a method may be implemented that allows for a direct interface (e.g., using the cellular network interface  280  of  FIG. 2 b   ) to 3G or any similar wireless network directly from the endpoint in a peer-to-peer hybrid system. When the endpoint is activated, the wireless module informs the wireless network of its presence. At this point, calls can be sent to and received from the wireless network. The endpoint can also bridge calls from the wireless side to the IP side of the network. For example, if a call is received from a wireless phone at the endpoint via the wireless interface, the endpoint&#39;s user can choose to route calls to any buddy endpoints on the IP side of the network. This bridging functionality is another capability of the endpoint. Similarly, calls received on the IP side can be bridged to the wireless side. 
     Referring to  FIG. 16 , in another embodiment, a method  1600  may be used with interactive voice response (IVR) (e.g., the IVR support provided by the feature layer  264  of  FIG. 2 b   ) to automatically handle calls when an auto-attendant is turned on. The auto-attendant provides functionality that allows users to perform other tasks when they are busy or not present to attend to calls or other forms of communication. The method  1600  may automatically terminate calls on behalf of the user and perform other tasks as defined by the user (e.g., leave a message or be routed to another destination). 
     In the present example, the method  1600  begins in step  1602  when the endpoint (e.g., the endpoint  104 ) receives a call. In step  1604 , a determination is made as to whether the auto-attendant is enabled (e.g., whether IVR functionality is on). If it is not enabled, the method continues to step  1606 , where the call is processed normally. If it is enabled, the call is accepted and the IVR functionality is started in step  1608 . In step  1610 , the call is connected. 
     Referring to  FIG. 17 , in still another embodiment, a method  1700  may be used to provide wiretap functionality on an endpoint the endpoint  104 ). Such functionality may be provided, for example, by the CALEA agent of the softswitch  258  of  FIG. 2 b   . The method begins in step  1702  when the endpoint  104  makes or received a call. If the endpoint is being tapped, as determined in step  1704 , the method will continue to step  1706 , where the start of the call will be logged. The method  1700  then continues to step  1708 , where the call is established. If the endpoint is not being tapped, the method skips step  1706  and proceeds directly to step  1708 . In step  1710 , a determination is made as to whether media associated with the call is to be captured. If so, the media is captured and securely streamed to a designated law enforcement agency in step  1712 . The method then continues to step  1714 , where call tear down occurs after the call is ended. If no media is to be captured, the method proceeds directly from step  1710  to step  1714 . In step  1718 , the end of the call is logged (if a wiretap is enabled as determined in step  1716 ) and the endpoint  104  returns to an idle state in step  1720 . In the present example, the log information is also securely streamed to the law enforcement agency as it is captured. 
     In another embodiment, a Find Me Follow Me (roaming) method may be used to provide simultaneous multiple sessions for the endpoint in the peer-to-peer hybrid environment. The endpoints can be signed in at multiple locations to access services offered and communicate directly in a peer-to-peer manner with other endpoints that are buddies. In this method, when one endpoint tries to contact his/her buddy, if the buddy is signed on at multiple locations, the originating buddy sends out messages to all signed in locations of the buddy. When the endpoint responds from any one of the multiple signed in locations, requests to other endpoints are dropped and communication is continued with the endpoint that has accepted the request for communication. 
     Referring to  FIG. 18 , in still another embodiment, a sequence diagram  1800  illustrates an exemplary process by which the endpoint  104  may stream data in real time to one or more other buddy endpoints  106  and  292  ( FIG. 2 g   ), either one at a time or simultaneously. In steps  1802  and  1804 , respectively, the originating endpoint (e.g., the endpoint  104 ) sends out a request to stream data to the endpoints  106  and  292 . The endpoints receiving the request may respond with messages either accepting or rejecting the request (steps  1806  and  1808 ). Once the request is accepted (as indicated in step  1810 ), the data stream is sent out to all buddies that have accepted the request for the data stream (steps  1812  and  1814 ). On the terminating endpoints  106  and  292 , the user chooses an application that can handle the processing of the data stream to utilize the data. It is understood that some applications may be automatically selected by the endpoint for recognized or predefined data types. The streams are then processed by the relevant endpoint (steps  1816  and  1818 ). In steps  1820  and  1822 , respectively, the endpoint  104  sends out a request to the endpoints  106  and  292  to terminate the stream. The endpoints  106  and  292  stop their processing in steps  1824  and  1826 , respectively. 
     In yet another embodiment, a method for Smart IM™ (as developed by Damaka, Inc., of Richardson, Tex.) or Enhanced IM may be used to convert textual data sent to and received by the endpoint into speech by employing a text-to-speech recognition system in real-time. Textual data can be received from the network or locally for conversion to speech/voice signals for playback. Such functionality may be provided, for example, by the text-to-speech engine  270  of  FIG. 2   b.    
     In another embodiment, a method to convert speech/voice data that is sent to and received by the endpoint into text form by employing a speech-to-text system in real-time. Speech/voice data can be received from the network or locally for conversion to text data for processing by the user. Such functionality may be provided, for example, by the speech-to-text engine  268  of  FIG. 2   b.    
     In one embodiment, a method may be used to provide correction services (e.g., spell check) on textual data being sent/received by the endpoint. In another embodiment, a method may provide functionality to allow a user to search the world wide web or internet via search engines for additional information related to textual data being sent/received by the endpoint. In yet another embodiment, a method may provide functionality for performing language conversion on textual data being sent/received by the endpoint using one or more language conversion engines (e.g., the language conversion engine  272  of  FIG. 2 b   ). 
     In still another embodiment, a method may provide functionality enabling textual data received by the endpoint to be archived on the endpoint for later retrieval. For example, a database (e.g., SQL) engine may be used to store and index data received by the endpoint from a buddy for faster retrieval. A standard query interface may then be used to store/retrieve data for presentation to the user. 
     In another embodiment, a method may be used to provide SMS functionality. Such functionality may be provided, for example, by the SMS feature of the feature layer  264  of  FIG. 2 b   . For example, an SMS table may be downloaded with the routing table when an endpoint logs onto the network. If the endpoint has a mobile setting, the endpoint may be able to communicate directly via the SMS functionality. 
     Referring to  FIG. 19 , in another embodiment, a sequence diagram  1900  illustrates an exemplary process by which the endpoint  104  may initiate a private transaction make an offer for sale or start an auction process) to buddies represented by endpoints  106  and  292  ( FIG. 2 g   ). In steps  1902  and  1904 , respectively, the endpoint  104  sends a message containing an offer to sale one or more items to the endpoints  106  and  292 . In steps  1906  and  1908 , respectively, the endpoints  106  and  292  may return messages accepting or rejecting the offer, or making a counteroffer. The user of the endpoint  104  may review the received messages and accept one, reject both, reply to one or both with an additional counteroffer, etc., in step  1910 . This process (offer, response, review) may continue until the offer is either finally accepted or rejected. In the present example, because the interaction occurs between buddies, the actual financial transaction may not occur electronically. 
     Referring to  FIG. 20 , in yet another embodiment, a sequence diagram  2000  illustrates an exemplary process by which the endpoint  104  may initiate a public transaction (e.g., make an offer or start an auction process). In step  2002 , the endpoint  104  sends a message to the access server  102  to post a sale. The message contains information such as a description of the item for sale, a starting price, and the start/end dates of the auction. In step  2004 , the endpoint  106  (which is not a buddy in the present example) obtains the sale information from the server. The obtained information includes a “substitute ID” of the endpoint  104  and associated address information. The substitute ID, which may be assigned to the endpoint  104  exclusively for the sale, enables the endpoint  106  to contact the endpoint  104  directly without obtaining the actual ID of the user of the endpoint  104 . Accordingly, when the sale ends, the endpoint  106  will no longer be able to contact the endpoint  104 . 
     In step  2006 , the endpoint  106  sends a message directly to the endpoint  104  with a bid. In step  2008 , the endpoint  104  updates the information on the access server with the bid and bidder information. Although not shown, buddy endpoints may also bid on the posted item. In step  2010 , the user of the endpoint  104  reviews the bids, selects a winner (if a winner exists), and notifies the winner directly (step  2012 ). In step  2014 , the sale transaction is handled. In the present example, because the transaction may occur between parties that are not buddies, the transaction may be accomplished via a third party clearinghouse. However, if a buddy won the sale, the parties may revert to a private transaction. Additionally, it is understood that any parties (whether or not they are buddies) may arrange the transaction as desired. In some embodiments, the process may include directly or indirectly notifying involved parties of a pending bid, notifying involved parties of accepted/rejected bids, etc. The seller may also accept any bid desired (e.g., not only the highest bid) and may end the bidding at any time. If an endpoint is offline when bidding occurs (e.g., if the endpoint  104  is offline when the message of step  2006  is sent or if the endpoint  106  is offline when the message of step  2012  is sent), the message may be downloaded during authentication when the endpoint logs in as previously described. 
     Referring to  FIG. 21 , in still another embodiment, a sequence diagram  2100  illustrates an exemplary process by which the endpoint  104  may initiate a conference call with other endpoints (e.g., the endpoints  106  and  1202 , both of which are buddies with the endpoint  104  in the present example). It is noted that the endpoints  106  and  1202  may or may not be buddies with each other. In steps  2102  and  2104 , respectively, the endpoint  104  sends a request to join a conference call to the endpoints  106  and  1202 . The endpoints  106  and  1202  respond in steps  2106  and  2108 , respectively, by either accepting or rejecting the request. In the present example, both endpoints  106  and  1202  accept the request (as indicated by step  2110 ). 
     The endpoint  104  may then send media (e.g., text or voice information) to the endpoints  106  and  1202  in steps  2112  and  2114 , respectively. Incoming media (e.g., from the endpoint  106 ) is received by the endpoint  104  in step  2116  and sent to the endpoint  1202  by the endpoint  104  in step  2118 . In the present example, rather than multicasting the information, the endpoint  104  hosts the conference call by using a separate peer-to-peer connection with each endpoint. As the endpoints  106  and  1202  are connected in the conference call via the endpoint  104  and are not communicating with each other directly, the endpoints  106  and  1202  do not need to be buddies. Accordingly, the endpoint  104  in the present example may have two routing entries associated with the conference call: one routing entry for endpoint  106  and another routing entry for endpoint  1202 . In other embodiments, multicasting may be used to transmit the data from the endpoint  104  to the endpoints  106  and  1202 . 
     It is understood that the process described with respect to  FIG. 21  may be applied to other scenarios. For example, the endpoint  104  may serve as the host for a multiplayer game. Incoming data may then be distributed by the endpoint to other endpoints that are associated with the hosted game. 
     Referring to  FIG. 22 , in another embodiment, a network environment  2200  includes the system  100 , which itself contains the access server  102  that is coupled to endpoint  104  via packet network  108 . In the present example, the endpoint  104  is coupled to an endpoint  2202  via a PSTN  2204  and a PSTN gateway  2206  or  2208 . The endpoint  2202 , PSTN  2204 , and PSTN gateways  2206  and  2208  are not part of the system  100  (e.g., the environment  2200  is a heterogeneous network environment). As illustrated in  FIG. 22 , there is no gateway positioned within the system  100  to couple the endpoint  104  with either of the PSTN gateways  2206  or  2208 . Accordingly, the endpoint  104  should be able to select and connect directly to one of the PSTN gateways  2206  or  2208  in order to connect to the endpoint  2202 . 
     With additional reference to  FIG. 23 , a method  2300  illustrates one process for dynamically selecting a gateway by the endpoint  104 . In step  2302 , the endpoint  104  performs digit collection. For example, the endpoint  104  may receive input from a user and collect the input as digits for a telephone number. In step  2304 , once the digit collection is complete, the endpoint  104  performs digit analysis to identify the called number (e.g., the number corresponding to the endpoint  2202 ). In step  2306 , the endpoint  104  dynamically selects one of the PSTN gateways  2206  or  2208  using a process based on the performed digit analysis and information previously obtained from the access server  102 . 
     In the present example, the process is based on the following:
 
 R=g ( f ( CN ), LO,TZe,TZg,RA )
 
     where R is the route, CN is the called number, LO is the location of a gateway serving the called number (e.g., the gateway  2206  or  2208 ), TZc is the time zone of the endpoint placing the call (e.g., the endpoint  104 ), TZg is the time zone of the gateway serving the called number, and RA is the rate (e.g., cost per minute) that will be applied to the call. The function “f” is a digit analysis function that splits the called number into its various components (e.g., country code, area code and number). The function “g” uses the components obtained, by f(CN) in conjunction with LO, TZc, TZg, and RA to arrive at a optimal route for making the phone call. In the present example, “g” is a lookup function of tables based on f(CN), LO, TZc, TZg, and RA. The information for LO, TZe, TZg, and RA is obtained by the endpoint  104  from the lookup tables downloaded from the access server  102  as previously described. 
     Accordingly, the endpoint  104  may select whichever of the PSTN gateways  2206  or  2208  provides the optimal route to the endpoint  2202 . It is understood that different routes may be optimal for different reasons. For example, one route may be optimal from a cost standpoint, while another route may be optimal from a transmission rate (e.g., quality) standpoint. In some embodiments, the process parameters may be modified by a user before being applied, thereby enabling the user to select the manner in which the route should be optimized. It is understood that additional parameters may be included. 
     One example of using the method  2300  with a lookup routing table to select a route based, on a minimum rate (e.g., a user requested minimum rate for call) is now provided. An example RA lookup routing table is shown below in Table 1. 
                                 TABLE 1               Country Code   Area Code   Rate   Route for Gateway                  91   44   0.20   sip.india.gateway       91   44   0.35   sip.us.to.india                    
If the called number is 9144XXXXXXXXXX, where XXXXXXXXXX is the phone number, then f(CN) would provide 91, 44, XXXXXXXXXX as the output based on Table 1. Next, the “g” function is applied based on the RA lookup table. In this case, since the route will be picked for the minimum rate, the “g” function will return sip.india.gateway as the route to use.
 
     Another example uses the method  2300  with a lookup routing table to select a route based on connection quality. An example LO lookup routing table is shown below in Table 2. 
                                 TABLE 2               Country Code   Area Code   Quality   Route for Gateway                  91   44   Low   sip.india.gateway       91   44   High   sip.us.to.india                    
In the present case, the user has chosen to select the route having the higher quality connection for the number 9144XXXXXXXXXX. Accordingly, the “g” function will return sip.us.to.india as the route to use.
 
     Referring to  FIG. 24 , in yet another embodiment, a heterogeneous system  2400  includes the system  100  as described with respect to  FIG. 22 , the endpoint  2202 , the PSTN  2204 , and the PSTN gateway  2206 . In the present example, the system  100  also includes a media router  2402  that is coupled to the endpoint  104  and the PSTN gateway  2206 . The media router  2402  enables the endpoint  104  to connect to the endpoint  2202  when the endpoint  104  includes a symmetric NAT that would prevent a direct connection from being established as described with respect to  FIGS. 22 and 23 . As is known, a symmetric NAT is one where all requests from the same internal IP address and port to a specific destination IP address and port are mapped to the same external IP address and port. If the same host sends a packet with the same source address and port, but to a different destination, a different mapping is used. Only the external host that receives a packet can send a UDP packet back to the internal host. 
     With additional reference to  FIG. 25 , a method  2500  illustrates one embodiment of a process that may be used within the system  2400  of  FIG. 24  to establish an outgoing audio call from the endpoint  104  to the endpoint  2202  via the media router  2402 . The method  2500  begins when the media router  2402  receives a request to establish a connection from the endpoint  104 . Upon receipt of the request, the media router  2402  creates a port in step  2502  and associates the IP address of the endpoint  104  with the created port on the media router  2402 . Although not shown in  FIG. 25 , the media router  2402  also notifies the endpoint  2202  of the created media router port to be used for the connection. In step  2504 , the media router  2402  waits for audio from either the endpoint  104  or the endpoint  2202 . 
     In step  2506 , upon receiving audio at the created port, the media router  2402  determines whether the IP address of the received audio corresponds to the IP address of the endpoint  104 . If the IP addresses match, the media router  2402  captures the port of the endpoint  104  used for the connection from the received audio in step  2508 . This enables the media router  2402  to send messages through the symmetric NAT to the endpoint  104 . In step  2510 , the media router  2402  determines whether it has destination information for the endpoint  2202 . If it does, the media router  2402  forwards the received audio to the endpoint  2202  in step  2512 . If not, it will ignore the audio in step  2511  and drop it without any forwarding. It will ignore audio from the endpoint  104  until step  2516  occurs. 
     Returning to step  2506 , if the IP address of the received audio does not correspond to the IP address of the endpoint  104 , the method will continue to step  2516 . In step  2516 , the destination IF address and port (of the endpoint  2202  in the present example) will be captured and stored by the media router  2402 . In step  2518 , the media router  2402  will determine whether the source port has been captured (which occurs in step  2508 ). If the source port has already been captured, the media router  2402  will forward the audio to the source IP address and port (e.g., the endpoint  104 ). If the source port has not been captured, it will ignore the audio in step  2522  and drop it without any forwarding. 
     While the preceding description shows and describes one or more embodiments, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the present disclosure. For example, various steps illustrated within a particular sequence diagram may be combined or further divided. In addition, steps described in one diagram may be incorporated into another diagram. For example, the STUN request/response steps of  FIG. 5  may be incorporated into diagrams that do not show this process. Furthermore, the described functionality may be provided by hardware and/or software, and may be distributed or combined into a single platform. Additionally, functionality described in a particular example may be achieved in a manner different than that illustrated, but is still encompassed within the present disclosure. Therefore, the claims should be interpreted in a broad manner, consistent with the present disclosure.