Multiplex communications – Pathfinding or routing – Switching a message which includes an address header
Reexamination Certificate
1999-09-16
2003-11-18
Marcelo, Melvin (Department: 2663)
Multiplex communications
Pathfinding or routing
Switching a message which includes an address header
C370S473000
Reexamination Certificate
active
06650650
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to network structures, and more particularly to a network apparatus and method for transmitting voice data from multiple channels in a multiplexed voice data packet.
BACKGROUND OF THE INVENTION
Network systems typically transmit data from one network location (a source location) to another network location (a destination location) by first placing the data into “packet” form. A packet can include information that allows a data packet to be directed from one network location to another by including certain information, including a “destination address,” that identifies a destination location. Such packet identifying information is typically placed in an initial portion of the packet, often referred to as a “header.” The header will include a number of fields, each of which includes a particular type of packet information. The data carried by the packet is often referred to as a “payload.” The process of generating packets from data is often referred to as “packetization.” In particularly large networks, packet data can be transferred from a source location to a destination location by way of one or more network nodes. A transmission from one node to the next can be referred to as a “hop.”
One particular type of network data that can be desirable is voice data. One approach to transmitting voice data over a network structure is referred to generally as “voice over Internet Protocol” (“VoIP”). Internet Protocol (IP) is one particular protocol for transmitting data over a network structure having devices that recognize the IP protocol. The wide reach of the Internet and wide use of IP in smaller networks makes VoIP an important application. VoIP can enable a local network, such as that shared by a corporation, to carry voice communications between the various users in addition to conventional sharing of data and/or applications.
Because most connections to the Internet are by way of a conventional telephone line or a higher speed connection (an integrated services digital network (ISDN), a “T-3” or “T-1” trunk line, or one of the many types of digital subscriber lines (xDSL), as just a few examples) the use of VoIP can provide long distance voice communications at considerable cost savings by avoiding the toll charges required by conventional long distance telephone calls. VoIP can prove extremely valuable to the telecommuter, as data and voice can both be transmitted to and from an office, allowing efficient communication between the remote worker and other on-site workers.
Another advantage of VoIP is the ability to transmit the same data packets to multiple destinations. This enables teleconferencing to occur over very large distances, again, without the unwanted expense of a conventional long distance telephone service provider.
Network structures can be “connectionless,” “connection oriented,” or some hybrid thereof. A connectionless structure provides a more flexible and robust network. Data paths between different points can vary according to available network resources. For example, a first data packet may be transmitted from a source location to a destination through a first series of hops, while a second data packet transmitted between the same two points could be transmitted by way of a different number of hops, by way of a separate set of nodes. In this arrangement, if a node becomes disabled, data can still be transmitted between two points. In this way, VoIP is particularly advantageous, as the transmitting structure is more robust.
One disadvantage to conventional approaches that transmit voice data over a connectionless structure is that transmitting too much data from a source location at a given time may result in too much latency (delay) in the voice data.
In contrast, a connection oriented network structure may seek to establish a dedicated path between two network points. Such network approaches include asynchronous transfer mode (ATM) switching and “IP” Switching. Such approaches can ensure “quality of service” (QoS) by ensuring sufficient resources exist in the dedicated path to prevent voice data from being unduly delayed. A drawback to connection-oriented network structures is that such approaches are usually more expensive, and can require more complex devices. In addition, setting up the initial dedicated path can introduce a further initial delay. Further, connection-oriented network structures can be more susceptible to failure in the event one or more of the nodes are disabled.
The transmission of voice data over the Internet is also referred to as “Internet Telephony” and can employ systems referred as “IP Phones.” It is expected that Internet Telephony will be a very important application for the Internet.
As noted above, a particular concern that arises out the transmission of voice data over a network structure is that of latency (delay). For example, for most data, some delay can be acceptable. Whether or not text and/or images are not immediately viewable may be of less concern than if the text and/or images are corrupted. Accordingly, many transmission protocols are more concerned with reassembling data in the proper order, and less concerned with the overall rate at which the data is transmitted. As just one example, a data file that is broken down into packets that are transmitted in a particular order, may receive the packets in a different order, and subsequently reassemble them in the correct order.
Voice data can be more susceptible to latency effects. As just one example, attempting to have a conversation over a data network can be extremely awkward when undue delay is introduced into the transmission of the voice data. The natural flow of conversation is often interrupted as a delay may be misinterpreted as the end of one person's conversation. Further, if data is lost, or multiple packets take too long to reassemble, speech can be broken up, with portions of the conversation being dropped.
Another concern in voice data over networks is the “random” or “asynchronous” nature of voice data. That is, if multiple parties are having multiple conversations, voice data may “bog down” a system, as the rate at which voice data is being received can exceed the rate at which a system can transmit the data (exceed the bandwidth of the system). This can be of particular concern when multiple speakers exist on a system that is connected via a high speed line to the Internet, or some other higher level network structure.
Conversely, another concern in voice over data networks can be efficiency. While it is desirable to provide a predetermined latency for voice data, it would be advantageous to take advantage of any extra available network bandwidth.
One approach to voice over data networks is the personal computer (PC) Internet phone or Internet videophone. Such approaches typically involve utilizing the microphone and sound card of a PC in conjunction with proprietary software. The central processing unit (CPU) of the PC, in conjunction with an analog-to-digital converter (typically in the sound card), converts the voice signal into digital form, and then transmits the data in a conventional fashion as a series of packets. A drawback to such approaches is that such systems provide a solution for only one voice data source, and must rely on conventional connectionless and/or connection oriented structures voice the transmission of the voice data. Hence, voice data can be unreliable, expensive, and/or incur unwanted latency.
Another approach to transmitting voice data over a structure can involve providing a conventional voice “gateway” to a larger network structure (such as the Internet). Such a conventional gateway can receive voice data from a number of different channels, and transmit the voice data onto the larger network structure. Such approaches may not be as efficient as desired. For example, the amount of voice data transmitted may be less than or greater than what the network is capable of handling.
One particular format for network data is a “multiplexed” packet. A multiplexed pa
Schneider Neal
Tsztoo Gary
Ferris Derrick W.
Fischer Felix L.
Marcelo Melvin
Sako Bradley T.
UT Starcom, Inc.
LandOfFree
Method and apparatus for transmitting voice data over... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method and apparatus for transmitting voice data over..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method and apparatus for transmitting voice data over... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3148398