JP2004533755A - Duplicate switch for streaming data units to terminals - Google Patents

Abstract

Receiving a stream of data units using a duplicating switch, storing content from the stream using a duplicating switch, and utilizing the duplicating switch to store the stored content and not part of the first stream A second stream including address information corresponding to two or more terminals having the same address information, and making the stream of the second data unit available to the two or more terminals using the duplication switch How to stream to the terminal by doing.

Description

【Technical field】
[0001]
The present invention relates generally to streaming media.
Background of the Invention
The term multimedia streaming refers to the process of making multimedia content accessible from one or more sources. The increasing use of the Internet has created an increasing demand for multimedia streaming.
[0002]
Summary of the Invention
In one general aspect, a data unit receives a first stream of data units, accumulates content of the first stream, and generates a second stream incorporating the accumulated content, The two streams can be streamed to the terminal using a replication switch that makes it available to the terminal.
[0003]
Implementations may include one or more of the following features. For example, storing content using the duplication switch may include storing content that is temporally related to the generated data unit. The location identifier may be used to indicate which part of the content will be generated in the second stream. The location identifier can be used to access the staggered content as two different streams. Storing the content utilizing the duplication switch also includes storing two or more instances of the same portion of the content, and storing additional instances of the stream as the demand for the content increases. May be included.
[0004]
Storing the content using the duplication switch may include storing the content and associated header information. Storing the content utilizing the duplication switch may also include storing a checksum representing the content.
[0005]
The second stream may be sent in response to receiving a request from a terminal or a service provider. Storing the content may include utilizing the location identifier to track the simultaneous transmission of a single stored instance of the stream, wherein making the stream available comprises: Transmitting different data units within to requesters having terminals receiving overlapping but staggered streams. The duplication switch includes one of receiving a stream of the first data unit, storing content of the first stream, generating a second stream, and making the second stream available. It can be a specialized device that includes hardware configured to perform one or more.
[0006]
In one general aspect, the performance of a network system includes a communication interface that receives a stream of data units, each including a payload portion and an attribute portion, and a configuration configured to store at least the payload portion of the data units. An arranged buffer, a replicator configured and arranged to replicate at least a payload portion of one or more data units, and enabling access by two or more terminals to a stream of data units. And a second communication interface configured and arranged to do so.
[0007]
Implementations may include one or more of the following features. For example, the attributes of a data unit may include IP packet information and / or one or more layer 3 information. The switch may include a processor that generates the attribute portion and associates the attribute portion with the payload portion duplicated by the replicator. The replicator may be configured and arranged to duplicate the payload portion and the attribute portion, and the processor may be configured and arranged to modify the IP header of one or more attribute portions duplicated by the replicator. .
[0008]
The processor may be configured and arranged to change the destination IP address, which may be, for example, an IP address corresponding to a terminal permitted to access the payload portion using the second communication interface. The processor may be configured and arranged to identify different destination information between the replicated payloads. Data units may include, for example, audio content, video content, and streamed media content.
[0009]
The switch may be configured and arranged to receive a request to receive a stream of data units from the terminal. The switch may then send the stream of data units to the requesting terminal. Implementations may include receiving a request from a device other than a terminal that receives the stream of data units, and the switch may send the stream of data units to the requesting terminal or device. The switch may allow access to the same stream of data units at two different times. The switch may include a buffer with two or more pointers that allow access to the stream of data units at two different points and times. The buffer may store more than one instance of the stream of data units.
[0010]
The source system may interface with the switch. The source system may be capable of replicating data units and transmitting streams of data units to the switch. Similarly, one or more terminals may interface with the switch and receive replicated data units from the switch.
[0011]
Implementations may include systems capable of achieving the above features, including, for example, systems including source systems, switches, terminals, and networks between components. Implementations may also include a series of steps performed on the switch, source system, and / or terminal to achieve these features.
[0012]
Other features and advantages will be apparent from the following description, including the drawings, and the claims.
In the various drawings, like reference numbers may indicate like components.
[0013]
Detailed description
Generally, a duplication switch receives a source stream of data units, stores the content of the stream, and allows for subsequent generation of one or more streams that capture the content. The step of storing the content allows the content to be staggered for later transmission. For example, an on-demand system may be created to transmit stored content from a source stream in response to a user request. The duplication switch may use one or more pointers to allow simultaneous access to different parts of the content from the same source stream, so that from a single source stream, several different A shifted stream can be generated at the same time. Duplicate switches may accumulate multiple instances of content from a source stream to meet increasing demands. Duplicate switches may also reduce the overall memory requirement by accumulating only certain portions of the content in the source stream.
[0014]
By way of example, FIGS. 1-11 depict communication systems that utilize duplicate switches to stream data units to terminals. For simplicity, some components in the figures described below are represented as being unitary. However, as will be appreciated by those skilled in the art, these components are each designed to perform a series of specific operations, and / or may comprise a plurality of interconnected computers occupied by specific map areas. And components.
[0015]
By way of example, FIG. 1 depicts a communication system 100 that implements a technique using duplicate switches to stream data units to two or more terminals. Communication system 100 may be configured and arranged to include source system 110, one or more terminals 150, and communication software and hardware that enable communication between source system 110 and terminals 150. More specifically, the communication system 100 typically includes a source system 110, a network 120, a duplication switch 130, a network 140, and a terminal 150. In an actual implementation, source system 110 typically sends one or more data units of a stream of data units to one or more replication switches 130 via network 120. In the duplication switch 130, the content of the data unit is stored, duplicated, and transmitted on demand to one or more terminals 150 via the network 140.
[0016]
Source system 110 provides a stream of one or more data units to duplicating switch 130 over network 120. Typically, source system 110 is configured and arranged to convert media sources (eg, video or audio feeds) into data units for transmission over network 120. Source system 110 may include a general-purpose computer with a central processing unit (CPU) and memory / storage, such as data and an operating system and one or more application programs. And accumulate various programs. Other implementations of the source system 110 include workstations, servers, devices, special purpose devices or components, other devices, or combinations thereof that can respond and execute instructions in a defined manner. Source system 110 also typically includes input / output (I / O) devices (eg, video and audio input and conversion functions) and display communication cards or devices (eg, modems or network adapters). And a peripheral device for exchanging data with the network 120.
[0017]
Implementations of source system 110 may also include a media system that transmits one or more media content over network 120. For example, the source system 110 may output a signal formatted according to the standards of the European Telecommunications Standards Institute (ETSI), Digital Video Broadcasting (DVB), the Next Generation Television Systems Commission (ATSC), or the European Cable Telecommunications Association (ECCA). , Over the network to the cable head end. In other implementations, a cable provider may send or direct a video signal to a cable head end for distribution within a cable network.
[0018]
Communication link 115 is used to transmit data between source system 110 and network 120. Communication link 115 may include a wired or wireless communication system such as a telephone line, wireless network link, cable network or direct connection.
[0019]
Network 120 typically includes hardware and / or software that may enable direct or indirect communication between source system 110 and replication switch 130. Network 120 may include a direct link between source system 110 and replication switch 130, or may include one or more networks or subnetworks (not explicitly shown) therebetween. Individual networks or sub-networks may include, for example, wired or wireless data paths through which data can be transmitted and received. Examples of network 120 include the Internet, the World Wide Web, a WAN (Wide Area Network), a LAN (Private Network), an analog or digital wired or wireless telephone network (eg, PSTN (Public Switched Telephone Network), ISDN ( Services Integrated Digital Network (xDSL) or xDSL (Digital Subscriber Loop of any form)), radio, television, cable, satellite, and / or other delivery mechanisms for transmitting data.
[0020]
Generally, the duplication switch 130 is configured and arranged to accumulate a stream of received data units for staggered transmission to two or more terminals. Implementations of the duplication switch 130 may accumulate a stream of one or more data units. For example, the duplication switch 130 may be able to receive a stream of IP (Internet Protocol) video and store the video for later transmission. Implementations of the duplication switch 130 may also include hardware or software capable of sending and receiving media feeds that are not similar to a stream of data units. For example, the duplicating switch may be transmitted and received by the European Telecommunications Standards Institute (ETSI), Digital Video Broadcasting (DVB), the Next Generation Television Systems Commission (ATSC), or the European Cable Communications Association (ECCA) for communication in cable distribution systems May include a cable head end system capable of The cable head end system may receive the satellite broadcast feed, convert the feed into a format suitable for storage, and then convert the feedback into a different format for staggered transmission.
[0021]
Network 140 generally includes one or more links between replication switch 130 and terminal 150. For example, network 140 may include direct physical links or a series of links connected by various network devices. In general, aspects of network 140 may be similar to aspects of network 120. For example, network 120 and network 140 may share one or more hardware or software devices. In other examples, networks 120 and 140 may utilize the same types of circuits and / or devices.
[0022]
Terminal 150 may include one or more devices capable of receiving a stream of data units transmitted over network 140 by replication switch 130. Terminal 150 processes instructions received or generated from software applications, programs, code, devices, computers, computer systems, or combinations thereof, that independently or collectively direct the operation of terminal 150. Controller (not shown). The instructions may be implemented permanently or temporarily in any type of machine, component, device, storage medium, or transmitted signal that may be delivered to terminal 150 or present in the controller of terminal 150. Terminal 150 may be a general-purpose computer (eg, a personal computer), a workstation, a laptop, a PDA (personal digital assistant), a wireless telephone, components, other devices, capable of responding to and executing instructions in a predetermined manner. Or a combination of these items capable of responding to and executing instructions.
[0023]
For example, in one implementation, the terminal 150 may receive one or more information retrieval software applications (eg, browsers, mail applications, instant messaging, etc.) capable of receiving one or more data units. Clients, Internet Service Provider Clients or AOL TV (American Online Television) or other integrated clients). The information retrieval application runs on a general purpose operating system and hardware platform, which includes a general purpose processor and special purpose hardware for rendering, communication and / or other functions. . In other implementations, terminal 150 may include a wireless telephone running a micro-browser application on a reduced operating system with general-purpose and special-purpose hardware operable in a mobile environment.
[0024]
In other implementations, terminal 150 may include a simplified device capable of receiving video signals that are not included in conventional data units. For example, the duplicating switch 130 may be a cable tuner or a cable tuner specified by, for example, the European Telecommunications Standards Institute (ETSI), Digital Video Broadcasting (DVB), the Next Generation Television System Committee (ATSC), or the European Cable Communications Association (ECCA). A raw video feed formatted according to specifications for direct transmission to television may be sent.
[0025]
In FIG. 2A, an example of the data unit 200A includes an attribute part 210A and a payload part 220A. Attribute section 210A typically includes parameters that are modified as data unit 200A moves through communication system 100. For example, an IP data unit may change layer 2 address information as the data unit passes through a network (eg, network 140). The payload 220A is typically information that is to be communicated from the source system and contains content and / or parameters that tend not to change frequently during transmission to maintain the integrity of the data being transmitted. Contains information including. For example, payload 220A may include audio or video content transmitted to a personal computer (eg, terminal 150).
[0026]
In FIG. 2B, the attribute portion 210B of the data unit 200B may include a number of separate or mixed fields, such as, for example, fields of an IP ("Internet Protocol") packet. More specifically, for example, the attribute unit 210B includes a destination address 213B, a source address 215B, an IP traffic format (for example, UDP (“User Data Protocol”), TCP (“Transmission Control Protocol”), It may include a port number 217B indicating ICMP ("Internet Control Message Protocol") and other parameters of various parts indicated by 211B and 219B. These fields may be arranged as shown or to accommodate various protocols. The payload of IP data unit 200B is represented by 220B.
[0027]
FIG. 3 illustrates a duplicating switch 300 configured and arranged to receive a stream, accumulate the contents of the stream, generate data units from the stream, and transmit the generated data units as a stream. Duplicate switch 300 generally corresponds to duplicate switch 130 of FIG. The duplication switch 300 generally comprises a storage system 310 for storing a stream of data units, a high speed interconnect 320 between the various subsystems of the duplication switch 300, and a stream of data units to two or more clients. A switching engine 330 for modifying and transmitting, a first communication interface 340 for receiving a stream of data units from the source system, and a transmitting engine for transmitting the stream of data units to two or more clients. And a second communication interface 350.
[0028]
The storage system 310 allows the duplication switch 300 to store at least the content portion of the data unit. Storage system 310 may be volatile or non-volatile and may include memory (eg, RAM) and / or storage (eg, HDDS). Implementations of storage system 310 may include a hard disk drive or more portable media such as, for example, a compact disk, a tape drive, or an optical memory device. Implementations may also include a combination of memory and storage.
[0029]
High-speed interconnect 320 generally refers to a device that connects one component of duplicate switch 300 to another component of duplicate switch 300. Examples of high-speed interconnects 320 include SCSI (“small computer system interface”), Fiber Channel, UTOPIA (“generic pilot PHY interface for ATM (“ asynchronous transfer mode ”)”), InfiniBand ( And other protocols and connection methods, but is not limited to such. High-speed interconnects may include physical, logical, temporal and electrical connections and standards, as well as protocols that allow data exchange by these high-speed interconnects.
[0030]
Generally, switching engine 330 includes devices that perform network operations on hardware (eg, a chip or a portion of a chip). In some implementations, the switching engine 300 is an ASIC (“application specific integrated circuit”) that implements the network operating logic directly on the chip (eg, formed on a silicon wafer and then manufactured on a chip) Logic gate). For example, an ASIC chip may include a logic gate structure implemented in silicon and configured to receive packets and filter based on checking an IP address.
[0031]
Implementations of the switching engine 330 may include the use of FPGAs ("field rewritable gate arrays"). An FPGA is generally defined as a chip formed to allow a third party to implement various logic designs (eg, groups of gates) on the chip. For example, one designer may load a design that replaces the IP address of a received IP packet with a different IP address. Other examples may include designs that perform IP packet segmentation and reassembly such that the IP packet is modified during transmission of the IP packet over various networks.
[0032]
Implementations of switching engine 330 may include the use of a network processor. A network processor is generally defined as a chip that, among other features, allows software to specify which network operation is to be performed. One example of a network processor may include a number of interconnected RISC ("Reduced Instruction Set Computer") processors formed on a network processor chip. A network processor chip may implement software on some RISC processors to change the IP address of an IP packet. Other RISC processors in the network processor may implement software that controls which terminals receive the IP stream.
[0033]
The switching engine 330 is configured to receive the data unit, extract content from the payload portion of the data unit, determine where the content is stored, and store the content in an organized manner. And an arranged precoder (not shown). Thereby, retrieval (e.g., playback) is performed that includes retrieving adjacent content, packaging the data unit around the content, and transmitting the data unit to one or more requesters. This step is described further below in connection with FIG.
[0034]
First communication interface 340 is generally configured and arranged to receive a stream of data units from a device such as, for example, source system 110. Implementations of the communication interface may include, for example, a LAN or WAN interface having the ability to send data units to one or more locations of the duplicate switch 300 using the high speed interconnect 320. Implementations may also include other forms of transmitting media signals including ETSI, DVB, ATSC or ECCA.
[0035]
The second communication interface 350 generally transmits the stream of data units from the storage system 310 to one or more devices generally corresponding to recipients, such as, for example, the terminal 150 described with respect to FIG. The configuration and arrangement are as follows. Implementations of the second communication interface 350 may include, for example, a LAN or WAN interface capable of sending data units to one or more locations of the duplicate switch 300 using the high speed interconnect 320. Implementations may also include other forms of transmitting media signals other than IP networking. In addition, the first communication interface 340 and the second communication interface 350 may include the same format, and may even include physically the same interface, while the second communication interface 350 It is not limited to the same type of format. For example, the first communication interface 340 may include a POS (“Packet over SONET”) interface, and the second communication interface 350 may be a form of Ethernet (eg, 100Base-T, Gigabit Ethernet (registered)). Trademarks)).
[0036]
FIG. 4A provides an example block diagram of a duplicating switch having a memory implementation (eg, duplicating switch 130 of FIG. 1). Duplicate switch 400A includes a RAM array 420A, a switching engine 430A, and a network interface 440A.
[0037]
RAM array 420A may include one or more RAM memory banks configured and arranged to store one or more content. RAM array 420A may store only a portion of the stream of data units. For example, a provider that streams movies may store a portion of the movie for several users who watch at the same time. RAM array 420A provides a time frame (eg, a movie) that a user can use to stagger the movie (eg, pause, stop playing, or rewind) while maintaining the flow of the movie being broadcast. , A 10 minute time frame).
[0038]
Within the RAM array 420A, there may be a location identifier that tracks or indicates which content to package and / or transmit to the terminal. For example, an OSP ("online service provider") may schedule a stream of data units to be transmitted to a terminal at a certain time. In one example, the duplication switch loads a portion of the stream of content indicated by the location identifier into the RAM array 420A. In this example, the duplication switch may utilize one or more pointers to indicate which content (eg, frames) should be sent to which user. In another example, the on-demand system loads a larger portion of the content into memory and utilizes the first pointer to transmit one stream of data units, simultaneously or otherwise. A second pointer may be utilized to transmit a second stream of data units.
[0039]
Switching engine 430A is configured and arranged to manage content stored in and retrieved from RAM array 420A. Aspects of switching engine 430A generally correspond to aspects of switching engine 330 of FIG. Switching engine 430A typically loads content into and retrieves content from RAM array 420A. Examples of content loaded and retrieved by switching engine 430A include MPEG ("Movie Expert Group") datagrams with I, P and B frames removed, video frames and changes between frames. Includes content without wrappers (eg, OSI wrappers), such as differential checksum values, and frames (eg, Layer 4 datagrams) with one or more additional wrappers. In one implementation, switching engine 430A may implement a system of pointers designed to record at what time or sequence number the terminal is at available stored content. Switching engine 430A may include devices, programs, software controllers, or other systems or devices in combination with the above. In other implementations, the switching engine 430A may manage the use of the entire system, reject later service requests, or attempt to serve more than one terminal from one data unit stream. .
[0040]
Network interface 440A is designed to transmit and receive streams of data units, and generally corresponds to first communication interface 340 and second communication interface 350 shown in FIG.
[0041]
FIG. 4B provides another example block diagram of a duplication switch 400B comprising a storage device implementation. Duplicate switch 400B includes a stream platform 410B, a switching engine 430B, and a network interface 440B.
[0042]
Stream platform 410B is configured and arranged to store content from a stream of data units. Stream platform 410B includes a hard disk drive 412B (or a tape drive or other magnetic memory) and an optical memory 416B. Generally, stream platform 410B includes memory components with low bandwidth characteristics but large capacity. For example, the storage device may include a solid-state memory (not shown) that operates slower than solid-state memory used in other applications. Because more capacity is available with less bandwidth, stream platform 410B typically stores a larger portion of the stream (eg, a movie), but without the RAM or other cache interface. Restricts access to fewer concurrent streams.
[0043]
An implementation of the storage platform 410B may include a disk storage device 412B with a RAM interface to the switching engine 430B. For example, a duplication switch may include a RAM bank and disk storage. Content may be loaded into disk storage so that it is retrieved in the order in which the content is transmitted. When content is retrieved, it is loaded into a RAM bank. The higher throughput performance of a RAM bank may allow more terminals to access the same content. A terminal accessing the stream of data units may utilize a pointer to the contents of the RAM bank to track and load the data units needed by the terminal within the stream of data units.
[0044]
Switching engine 430B is configured and arranged to manage the content stored and retrieved at stream platform 410B. Switching engine 430B generally corresponds to switching engine 430A described with respect to FIG. 4A. Network interface 440B is designed to transmit and receive streams of data units and generally corresponds to first communication interface 340 and second communication interface 350 described with respect to FIG.
[0045]
The RAM-based and storage-based systems described with respect to FIGS. 4A and 4B may have limitations common to existing memory and storage systems (e.g., solid-state RAM provides high throughput but has low storage capacity). FIG. 2 illustrates an implementation designed to compensate for (hard drive and optical memory provide greater storage capacity but lower throughput). However, implementations are not limited to those shown, and memory and storage devices are not necessarily subject to these restrictions. For example, disk drives can be utilized to implement systems that can manage multiple pointers to provide higher bandwidth, and solid-state memory provides higher density storage than disk drive storage. obtain.
[0046]
FIG. 5 shows an example of a duplication switch 500 having a precoder function. Duplicate switch 500 generally corresponds to duplicate switch 130 of FIG. The duplication switch 500 includes a data unit interface 510, a content extraction system 520, a content placement system 540, and a content storage device 550.
[0047]
Data unit interface 510 is typically designed and arranged to interface with a network that sends and receives data units to and from content storage device 550. In general, the functions of data unit interface 510 correspond to the functions of first communication interface 340 and second communication interface 350 of FIG. The data unit interface 510 may also be configured to segment and reassemble the divided data units during transmission, or to handle non-standard data units. For example, data unit interface 510 may be configured to send and receive one or more media frames (eg, frames formatted according to one of ETSI, DVB, ATSC or ECCA). In one example, if the duplication switch 500 receives an analog signal, the data unit interface 510 may convert the signal into a recognized format in which the frame or content can be stored.
[0048]
Content extraction system 520 is configured and arranged to remove data unit wrappers added around the transmitted content. For example, the content extraction system 520 may remove one or more bits associated with OSI ("Open System Connection") information contained in the transmitted content. Content extraction system 520 may also add wrappers as data is retrieved from content storage 550 for later transmission. For example, the content extraction system 520 removes the wrapper information when storing the stream of data units in the content storage device 550, and adds another wrapper when transmitting the stream of the data unit from the content storage device 550. obtain.
[0049]
The content placement system 540 is configured and arranged to instruct storage and retrieval of content information such that the content information can be retrieved in a predetermined manner. For example, the content may be arranged such that the address information can be updated with a predictable increment. In another example, the content may be arranged such that differences between frames of the content can be calculated by analyzing an associated checksum that may be stored.
[0050]
Determining where content can be stored, and storing the content, may include using a hard disk drive dedicated to storing the content. For example, the content storage 550 (eg, a hard drive) may store related content (eg, adjacent frames of a movie or adjacent MPEG I, (P and B frames).
[0051]
Determining where content can be stored, and storing the content, can include using solid state storage (eg, various forms of RAM) to store the content. For example, a solid-state storage device may store all or some of the streams in a RAM memory array. If a portion of the RAM memory is used to store content, the RAM memory may load the content for a certain time frame for transmission to one or more terminals. In some implementations, the duplication switch may store more than one instance of the stream of data units in the RAM array.
[0052]
Content storage device 550 is configured and arranged to store content or frames. As described above with respect to the content placement system 540, the content is generally configured and arranged to be retrieved in a manner that allows for transmission of related content to one or more terminals. Content storage device 550 generally corresponds to storage system 310 of FIG. 3, RAM array 402A of FIG. 4A, and storage platform 410B of FIG. 4B.
[0053]
FIG. 6 illustrates a method of transmitting a stream of data units in a communication system 600. Communication system 600 generally includes a source system 610, a switch 620, and terminals 650 and 670. In general, source system 610 corresponds to source system 110 in FIG. 1, switch 620 corresponds to switch 130 in FIG. 1, and terminals 650 and 670 correspond to terminal 150 in FIG.
[0054]
First, the source system 610 creates or enables access to the stream of data units on demand or otherwise (step 613). If the stream is taken from an analog input (eg, analog audio or analog video), this step may include converting the input into a stream of data units. Allowing access to the stream of data units, even if the input is already digital, may include modifying the input to a properly formatted stream of data units. The stream of data units may include various media streams (eg, video, audio, images, text, and chat). Typically, the data units are IP (Internet Protocol) packets transmitted over the Internet. Source system 610 then sends the generated stream of data units to one or more switches 620 (eg, via network 120) (step 616).
[0055]
Upon receiving a data unit from source system 610 (step 622), switch 620 typically buffers and duplicates at least the payload portion of the data unit (step 624). In some implementations, attributes of the data unit may be removed before buffering the payload. For example, for communication over the Internet, switch 620 may strip IP header information and store only the payload and / or the information represented by the payload. When the data unit is sent to the terminal, switch 620 modifies the existing header or adds a new IP header to the payload. The switch may use destination information corresponding to the IP address of the destination terminal (eg, terminals 650 and 670), or may use a relay point between switch 620 and the destination terminal as the destination information. Using the newly obtained destination information, the switch 620 transmits an IP packet to a suitable terminal, for example, the terminal 670 of FIG. 6 via a network (for example, the network 140 of FIG. 1) (step 626). ).
[0056]
Terminal 670 receives the stream of data units transmitted by switch 620 over the network (step 672), then converts the data units to a perceptible output, operates the data units, or Transfer the data unit to another device. For example, terminal 670 may receive a stream of IP data units containing video content and display or manipulate the video content on a personal computer or other device.
[0057]
In some implementations, a terminal may request a stream. For example, in FIG. 6, terminal 670 is depicted as automatically receiving a stream of data units (step 672), but terminal 650 generates a request to receive a stream of data units (step 652). ) May be possible. Upon receiving the request (step 628), switch 620 may send a stream of one or more data units to terminal 650 (step 630). Terminal 650 then receives the transmitted stream of data units (step 654).
[0058]
In some implementations, switch 620 and terminals 650 and 660 may be required to communicate periodically to maintain streaming. For example, terminal 650 may transmit a "keep stream alive" message every 10 seconds during a stream transmission to indicate that terminal 650 wants to receive the stream.
[0059]
While receiving a stream (step 654), terminal 650 may request another stream (step 652) or request a stop of transmission by sending a request to stop transmitting a stream of data units. (Step 656). Upon receiving a stop request or detecting the end of a stream (step 632), switch 620 stops transmitting the stream of data units (step 634).
[0060]
Terminal 650 may determine to resume transmitting the stream of data units and communicate this determination to switch 620 (step 658). When the switch 620 receives the resume command (step 636), the switch resumes transmitting the stream (step 638), and the terminal 650 receives the stream (step 660).
[0061]
In some implementations, when switch 620 receives a stream of IP data units from source system 610, switch 620 duplicates the payload portion of the data unit and switches the IP address of one or more conference terminals. The destination IP address of the IP data unit specifying the address may be modified or replaced.
[0062]
Terminal 620 typically transmits any particular payload or the entire payload in order for the received data unit payload to be transmitted as the payload of some or all of the data units generated by switch 620. Can be duplicated more than once. Moreover, switch 620 may receive one data unit and transmit the payload as two or more data units.
[0063]
Conversely, switch 620 may receive and combine two or more data units and transmit the combined payload of multiple data units in one data unit. Alternatively, switch 620 may split the payload of the received data unit and combine the split portion with the payload of two or more other received data units.
[0064]
As described with respect to FIG. 7, because the payload is buffered, the switch 620 generates several instances of the buffered payload simultaneously with or without offset, the same or different requiring different instances of them. May be sent to the terminal. These instances may be streamed at various time intervals so that terminal 650 may receive the stream of data units at a different time than terminal 670. For example, terminal 650 may receive the same song as terminal 670 at an Internet radio station, but terminal 650 may receive a data unit corresponding to that song 30 seconds later in time.
[0065]
FIG. 7 illustrates an example of the flow of IP data units from source system 710 to terminals 770, 780, and 790. IP address X. The 1.1.1 source system 710 sends the IP packet 720 to the destination address Y. 1.1.1 to switch 730. IP packet 720 includes the address of the switch as destination address 724 and the address of the source system as source address 726. IP packet 720 may also include other header information 722 and payload 728.
[0066]
Y. The switch 730 having a source address of 1.1.1 duplicates at least the payload 728 of the IP packet 720 and converts the IP data unit 740 to 1. Send to terminal 770 with address 1.1.1. The IP data unit 740 includes the source IP address 746 of the switch 730 along with the destination address 744 of the terminal 770. IP data unit 740 may include additional header information 742 and payload 748. Similar operations are performed to generate IP data units 750 and 760 for terminals 780 and 790.
[0067]
FIG. 8 illustrates a procedure 800 for storing and transmitting data units using a duplicating switch. In general, procedure 800 may be performed using one of the duplication switches described with respect to FIGS.
[0068]
First, the duplication switch receives a data unit (step 805) and selects content from the data unit (step 810). Typically, selecting the content of the data unit includes identifying fields or portions of the data unit corresponding to the content and removing some or all features unrelated to the content. For example, the duplicating switch may strip one or more layers of the OSI ("open intersystem connection") header and store the rest of the data unit as content. In another example, selecting the content includes creating or modifying a location identifier to identify which portion of the data unit should be stored when the data unit is loaded into memory. obtain.
[0069]
Selecting the content may include allowing one or more portions of other features of the data unit to be retained with the content. For example, one or more fields of the OSI header may be stored and stored as content.
[0070]
Implementations may include the use of a precoder to modify or adjust the stored content. For example, a precoder may compress the content so that less bandwidth is consumed during transmission. In another example, the precoder may calculate a checksum or shortcut that indicates the difference between the content. This checksum or shortcut may be stored instead of storing some content.
[0071]
The duplication switch determines the location in the storage system where the content is to be stored (step 820). Typically, the storage location of the content is selected such that the relevant content is retrieved in the relevant operation. Examples of related content may include content in successive frames and / or time slices of the video. The duplication switch then stores the content in the determined location (step 830).
[0072]
Later, the duplication switch receives the request for content (step 840). Receiving the request for content may include causing a user (eg, terminal 150 of FIG. 1) to request a video stream for display on the user's home computer. Implementations may also include having other devices request the content. For example, a cable modem operating as a set top box may request content for display on a television.
[0073]
Implementations may also include generating the request from a source other than the intended destination. For example, a cable system administrator may generate a request for content on behalf of one or more subscribers.
[0074]
Duplicate switch 130 determines which content was requested (step 850). The requester may indicate to send the content. For example, the terminal may keep track of which content was received and generate a request for one or more content (eg, missing frame number 100). Implementations may also include having the duplication switch record which content was requested. For example, a duplication switch may attempt to send the same content to several users.
[0075]
Duplicate switch 130 determines where the content is loaded (step 860). As such, the duplicating switch may utilize the location identifier described with respect to FIGS. Other implementations may employ a file and / or archiving system that is maintained to manage access to content.
[0076]
The duplication switch 130 extracts the content (Step 870). The duplication switch may retrieve the content by reading the memory location specified by the location identifier. Other implementations may include retrieving multiple pieces of content information (eg, reading sectors on a disc).
[0077]
Duplicate switch 130 packages the content into data units (step 880). For example, a duplicating switch may add one or more layers of OSI information (eg, address information). Implementations in which one or more characteristics other than the content of the data unit are stored with the content may include modifying one or more parameters of those fields. For example, as Internet Protocol packets are accumulated, the destination address may be modified to the requesting user's address.
[0078]
Finally, the duplication switch sends the data unit to one or more terminals (step 890). Data units may be sent in formats other than IP addressing. For example, transmitting a data unit may include transmitting an on-demand channel over a network.
[0079]
In FIG. 9, the function of the communication system 900 is described. Communication system 900 generally includes a source system 902, a management device 904, a duplication switch 906, and terminals 908 and 910. In general, source system 902 corresponds to source system 110 in FIG. 1, duplicate switch 906 corresponds to duplicate switch 130 in FIG. 1, and terminals 908 and 910 correspond to terminal 150 in FIG. The management device 904 may include a cable system operator, an OSP, a content provider, or a person who can provide commands or instructions to the duplication switch 906.
[0080]
As shown, source system 902 generates a stream of data units (step 913). Source system 902 sends the stream of data units to duplication switch 906 (step 916).
[0081]
Duplication switch 906 receives the stream of data units (step 925). Duplicate switch 906 then accumulates at least the content portion of the stream of data units (step 927).
[0082]
The stream may be sent in various ways. In some implementations, the management device 904 waits for a condition to appear (step 918). For example, the management device may be a scheduler programmed to instruct the duplication switch to "broadcast". When a condition appears (step 920), the management device 904 transmits a request to transmit a stream of data units to the duplication switch 906 (step 923).
[0083]
Alternatively, terminal 908 may generate a stream request (step 933). For example, terminal 908 may generate a viewing request for a particular video stream. The duplication switch 906 receives the request (step 930).
[0084]
In an implementation generally corresponding to the system described with respect to FIG. 4A, the duplication switch 906 may load one or more content into high speed memory (eg, RAM) (step 931). For example, the duplication switch 906 may determine that bandwidth to existing content storage devices is scarce and load frequently accessed content into high-speed memory to increase capacity.
[0085]
Regardless of the mechanism utilized to indicate when to send the stream of data units to the terminals, the duplication switch 906 may send the stream of data units to two or more terminals 908, 910 (step 936). ). In some implementations, a terminal receives a stream that has been broadcast or automatically transmitted to a stream recipient without requesting a stream of data units. In either case, terminals 908 and 910 receive the stream of data units (steps 940 and 940A). Depending on the implementation, different “stacks” of content may be loaded into memory supporting terminal 910.
[0086]
In some implementations, terminal 908 may generate and send a pause message (step 945). For example, the terminal may want to "pause" the video-on-demand stream and return to the stream later. When the duplication switch 906 receives the suspension message (step 950), the duplication switch 906 suspends transmission to the terminal 908 (step 955). Duplicate switch 906 may continue to transmit a stream of data units to terminal 910 (not shown). The pause message can be implemented in various ways. For example, terminal 908 may resume where it left off by recording which data unit was received and generating and transmitting a resume message (step 960). Other examples may include having the terminal 908 send a stop message and causing the duplication switch 906 to record where to resume when a resume transmission message is received (step 960).
[0087]
If the duplication switch 906 receives the resume message (step 965), the duplication switch 906 sends a stream 970 of data units to the terminal (step 970). Terminal 908 receives the stream of data units (step 975).
[0088]
FIG. 10A illustrates a duplicating switch 1000A configured and arranged to accumulate multiple instances of a stream of data units. Duplicate switch 1000A includes two streams of data units, Stream A and Stream A.¹Send Stream A occupies memory storage 1010A in the memory bank and stream A¹Occupy memory storage 1020A in the memory bank. In one implementation, a first pointer 1015A to memory storage 1010A indicates which content should be included as a data unit and delivered to the terminal requesting stream A compared to other content. Is shown. As already mentioned, implementations may include storing a portion of the content in a memory bank. For example, if a problematic network condition prevents a terminal from receiving a portion of a stream of data units, the terminal may not receive a portion of the content, and a break in receiving the stream of data units ( For example, missing time of a movie).
[0089]
A second pointer 1025A to the memory storage 1020A indicates which part of the content contained in the stream of data units is transmitted to several terminals. One or more terminals that desire to receive one or more data units in the stream of data units receive the content corresponding to the second pointer 1025A, and the second pointer 1025A Content can be constantly advanced. In some implementations, the second pointer 1025A hastens some content and may include more than one content in one data unit.
[0090]
FIG. 10B illustrates a duplicate switch 1000B configured and arranged to store a plurality of location identifiers. In this example, the duplication switch 1000B includes the five contents of stream A, A1 1010, A2 1020, A3 1030, A4 1040 and A5 1050. Duplicate switch 1000B also includes a memory area allocated for expected content A6 1060.
[0091]
In one example, replication switch 1000B allows individual terminals T, U and V to receive their own stream of data units. Each terminal manages a location identifier (eg, pointer) that instructs the duplication switch to select the appropriate content to be transmitted. For example, terminals T, U and V may start by requesting content A1 1010 simultaneously.
[0092]
After some content has been transmitted, as shown in FIG. 10B, location identifier 1025 for terminal T references content A2 1020 and location identifiers 1042 and 1044 for terminals U and V , Content A4 1040 corresponding to different time lags from content A2. This shift may occur, for example, because terminal T has paused receiving the stream of data units and has received content that is delayed compared to the content received by terminals U and V.
[0093]
In another example, the duplication switch 1000B includes the five contents of stream B: B1 1070, B2 1071, B3 1072, B4 1073, and B5 1080. Duplicate switch 1000B also includes a memory area allocated for expected content B6 1090. In one implementation, stream B may be part of the same stream of data units as stream A, but may correspond to a different part of the stream of data units. For example, stream B may be a “video” stream 5 minutes after the start of one video stream, while stream A may be 40 minutes after the start of the same video stream. In another example, stream B may be the same as stream A, but with an addition to achieve better system performance. In yet another example, stream A and stream B may represent completely different video streams (eg, two different television channels).
[0094]
FIG. 11 illustrates a procedure 1100 for implementing a “pause” function on a duplicate switch as described with respect to FIGS. First, the duplication switch receives the stream of data units (step 1110) and accumulates content from the stream of data units (step 1120). With the content stored and ready for transmission, the duplication switch waits for a request to play the stream of data units (step 1130). The duplicating switch may wait for a play request message, but in some implementations, the duplicating switch may start transmitting (eg, playing) upon receipt of the stream. In this configuration, the content can be stored only when the user requests a pause in the stream.
[0095]
In an optional implementation, the duplication switch may load the stream (content) into high speed memory (step 1140). This generally corresponds to loading the stream into the high speed memory described with respect to FIG.
[0096]
The duplication switch sends the stream of data units (step 1150). While transmitting the stream, the duplication switch 130 may receive a suspend request (step 1160). If the duplication switch 130 receives the suspend request, the duplication switch stops sending the stream of data units to the terminal (step 1165). When the stream of data units is paused, the duplication switch 130 may wait to receive a play request (step 1170).
[0097]
Upon receiving the playback request, the duplication switch 130 continues to transmit the stream of data units from where the terminal left off (step 1180). If no play request is received, the duplication switch 130 waits for a restart request. When the terminal resumes receiving the stream of data units, the duplication switch checks for a new suspend request (step 1160).
[0098]
If the duplication switch 130 does not receive the suspend request, the duplication switch may receive the stop request or reach the end of the stream (step 1185). If a stop request is received or the end of the stream of data units is reached, the duplication switch stops transmitting (step 1190). If not, the duplication switch 130 continues transmission and returns to waiting for a suspend request (step 1160).
[0099]
Stopping transmission may include automatically selecting a stream of other data units to be transmitted. For example, the duplication switch 130 may select another video to send when one video ends.
[0100]
Instead of resuming transmission of the stream at the point where the stream was presented, the stream may be repositioned earlier in the stream (eg, 30 seconds for commercials, 15 seconds for sporting events). An “instant play” or rewind function can be created using a similar process except that it is sent. For example, the duplication switch may load the content representing the stream 30 seconds ago from memory and transmit the content starting at an earlier time (continued from that time).
[0101]
Other implementations are within the scope of the claims. In particular, in some implementations, the terminal includes a set top tuner set that receives an analog signal. Also, the location identifier shown in FIG. 11 may be held by a client or a separate server or device to indicate which content the terminal may receive.
[0102]
Implementations may include a management device requesting stream transmission to a terminal. The management device may include a network operator, a management server, a workstation or a scheduling agent. For example, an administrative workstation may request transmission of a stream of data units to a terminal beginning at a particular time.
[0103]
Implementations may also include storing two or more instances of the stream of data units in a buffer. For example, a switch may accumulate more than one copy of a stream to accommodate a large number of requests. In another example, a stream may buffer a stream of the same data unit at two different points.
[0104]
Implementations may also include having the switch maintain state information for one or more requesting users. For example, the switch may install or assist other devices in defining the profile of the terminal receiving the stream of data units. Thus, the switch uses information available to network processors and devices in defining the profile that is not normally accessible to the server.
[0105]
Further, implementations may include monitoring switch access and utilization levels. For example, the switch may determine that at a given metric (eg, processor utilization, memory utilization, number of users, bandwidth), the switch is operating at 85% of maximum performance.
[0106]
Implementations may include translating or converting content between different formats. For example, a switch may coordinate the transmission of packets to minimize the bandwidth consumed. In another example, the switch may convert a proprietary video encoding format to a standards-based encoding format.
[0107]
Implementations may also include inserting one or more content into a stream of existing data units. For example, a switch may insert a video stream advertisement into the transmission of other video content. The inserted video content may be present on the switch or accessed from other devices remote from the switch transmitting the stream of data units. Implementations of inserting the content may include creating a tag associated with the particular content to be copied. For example, a switch may duplicate a television show with commercials periodically tagged in the video content. Upon receiving the tag, the switch stops transmitting the television show and may access a series of advertisements. Implementations may include having the tag indicate which advertisements to access. For example, the tag may indicate the device on which the advertisement is placed. Tag implementations may also allow access to more than one selected advertisement. The selection of the advertisement may depend on one or more variables, including but not limited to terminal information and profile, network information, and other factors.
[0108]
In addition, implementations may include inserting content based on retained information about a user profile and user state. For example, the switch may determine that the terminal is at the appropriate location in the content to receive an advertisement inserted for a user with a particular profile.
[0109]
Sources, networks, on-demand systems and terminals may also be located on different things within the communication system and may utilize one or more agents and / or proxies that perform particular functions.
[Brief description of the drawings]
[0110]
FIG. 1 is a block diagram of a communication system that can generate a stream of data units utilizing a duplication switch.
FIG. 2A is a diagram of an example data unit that may be transmitted in a communication system as shown in FIG. FIG. 2B is a diagram showing an example of the structure of the attribute unit of the data unit in FIG. 2A.
FIG. 3 is a diagram of exemplary components of a duplicating switch suitable for use in the communication system of FIG. 1;
FIG. 4A is an exemplary block diagram of a duplication switch that utilizes a memory (eg, a RAM (“random access memory”)) that stores media streams for later playback.
FIG. 4B is a block diagram as an example of a duplication switch utilizing a storage device that stores media streams for later playback.
FIG. 5 is a block diagram of a precoder used in the duplication switch.
FIG. 6 is a flowchart illustrating a method for transmitting data units in a communication system such as the communication system of FIG.
FIG. 7 is a flowchart illustrating the movement of an IP packet through the communication system of FIG. 1;
FIG. 8 is a flowchart of a procedure for processing a received data unit using a duplication switch in a communication system such as the communication system of FIG. 1;
FIG. 9 is a flowchart of a procedure for providing a stream of data units in a communication system such as the communication system of FIG.
FIG. 10A illustrates a duplicate switch configured and arranged to accumulate multiple instances of a stream of data units.
FIG. 10B illustrates a duplicate switch configured and arranged to store a plurality of location identifiers.
FIG. 11 is a flowchart of a procedure for shifting a content time in a communication system such as the communication system of FIG. 1;

Claims (88)

A method of streaming a data unit to a terminal, comprising:
Receiving a stream of the first data unit utilizing a duplication switch;
Storing the content of the first stream using the duplication switch;
Utilizing the duplication switch to generate a second stream that captures the stored content for use by more terminals having address information that was not part of the first stream; ,
Making the second stream available from the terminal using the duplication switch;
And wherein the duplication switch is configured to duplicate a portion or more of the first stream. The method of claim 1, wherein storing the content using the duplicating switch comprises storing content temporally associated with the data unit to be generated. The method of claim 1, further comprising the step of utilizing a location identifier to indicate which portion of the content is generated in the second stream. 4. The method of claim 3, further comprising utilizing a location identifier to access the content staggered as two different streams. The method of claim 1, wherein storing the content using the duplication switch comprises storing two or more instances of the same portion of the content. The method of claim 5, wherein storing the content utilizing the duplication switch comprises storing additional instances of the stream as the demand for the content increases. The method of claim 1, wherein storing the content using the duplication switch comprises storing the content and associated header information. The method of claim 1, wherein storing the content using the duplication switch comprises storing a checksum representing the content. The method of claim 1, wherein at least one of the second streams is transmitted in response to receiving a request from a terminal. The method of claim 1, wherein the second stream is transmitted in response to receiving a request from a service provider. The method of claim 1, wherein
Storing the content comprises utilizing a location identifier to track simultaneous transmission of a single stored instance of the stream;
Transmitting the various data units in the single stored instance to a number of requesters having terminals receiving the streams that overlap but are staggered A method comprising the steps of: The method of claim 1, wherein the duplicating switch receives a stream of a first data unit, stores content from the first stream, generates a second stream, and A method that is a specialized device that includes hardware configured to perform one or more of the steps of making said second stream available. Means for receiving a stream of the first data unit;
Means for storing content from the first stream;
Generating means for generating a second stream incorporating the stored content for use by more terminals having address information that was not part of the first stream; Generating means configured to duplicate one or more parts;
Means for making said second stream available to said terminal;
A replication switch comprising: 14. The duplicating switch of claim 13, wherein the means for storing content includes means for storing content temporally associated with the data unit to be generated. 15. The duplication switch of claim 14, further comprising means for utilizing a location identifier indicating which portion of the content is generated in the second stream. 16. The duplication switch of claim 15, further comprising means for utilizing a location identifier to access the content staggered as two different streams. 14. The duplication switch of claim 13, wherein the means for storing content includes means for storing two or more instances of the same portion of the content. 18. The duplication switch of claim 17, wherein the means for accumulating content includes means for accumulating additional instances of the stream as demand for the content increases. 14. The duplicating switch of claim 13, wherein the means for storing content includes means for storing content and associated header information. 14. The duplicating switch of claim 13, wherein the means for storing content includes means for storing a checksum representing the content. 14. The duplicating switch of claim 13, wherein the means for making the second stream available includes means for transmitting at least one of the second streams in response to receiving a request from a terminal. Duplicate switch. 14. The duplicating switch of claim 13, wherein the second stream is transmitted by the method for making the second stream available in response to receiving a request from a service provider. The duplication switch according to claim 13, wherein
Means for storing the content includes means for utilizing a location identifier to track simultaneous transmission of a single stored instance of the stream;
Means for transmitting transmits the various data units in the single stored instance to some requesters having terminals receiving the streams that overlap but are staggered Duplicate switch including means for doing. 14. The duplicating switch according to claim 13, wherein said generating means receives a stream of a first data unit, stores content from said first stream, and generates a second stream. And a specialized switch that includes specialized equipment that includes hardware configured to perform one or more of the steps of making the second stream available. A first communication interface configured and arranged to receive the stream of the first data unit;
A storage processor configured and arranged to store content from the first stream;
A switching processor configured and arranged to generate a second stream incorporating the stored content for use by more terminals having address information that was not part of the first stream. A switching processor configured to replicate one or more portions of the first stream;
A second communication interface configured and arranged to make the second stream available to the terminal;
A replication switch comprising: 26. The duplicating switch of claim 25, wherein the storage processor is configured and arranged to store content that is temporally related to the data unit being generated. 27. The duplication switch of claim 26, further comprising a first memory processor configured and arranged to utilize a location identifier indicating which portion of the content is generated in the second stream. switch. 28. The duplication switch of claim 27, further comprising a second memory processor configured and arranged to utilize a location identifier to access the content staggered as two different streams. switch. 26. The duplication switch of claim 25, wherein the storage processor is configured and arranged to store two or more instances of the same portion of the content. 30. The duplication switch of claim 29, wherein the storage processor is configured and arranged to accumulate additional instances of the stream as demand for the content increases. 26. The duplicating switch of claim 25, wherein the storage processor is configured and arranged to store content and associated header information. 32. The duplication switch of claim 31, wherein the storage processor is configured and arranged to store a checksum representing the content. 26. The duplication switch of claim 25, wherein the second communication interface is configured and arranged to make available at least one of the second streams in response to receiving a request from a terminal. Replication switch. 26. The duplicating switch of claim 25, wherein the second stream is transmitted by the second communication interface in response to receiving a request from a service provider. 26. The duplication switch of claim 25,
The storage processor is configured and arranged to utilize a location identifier to track simultaneous transmission of a single stored instance of the stream;
A number of requests, the terminal having the terminal receiving the streams overlapping, but staggered, the various data units in the single stored instance, Duplicating switch configured and arranged to transmit to a third party. 26. The duplicating switch of claim 25, wherein the switching processor receives a stream of a first data unit, stores content from the first stream, and generates a second stream. A duplicating switch that is a specialized device that includes hardware configured to perform one or more of the steps and making the second stream available. A method of transmitting a packet,
Utilizing a switch to receive a stream of data units including a payload portion and an attribute portion;
Using a switch to duplicate at least the payload portion of the data units of the stream;
Using a switch to allow two or more terminals to access the duplicated payload portion of the data unit;
A method that includes 38. The method of claim 37, wherein the data unit comprises an Internet Protocol packet. 39. The method of claim 38, wherein the attribute of the data unit includes an Internet Protocol header. 38. The method of claim 37, wherein the attribute of the data unit specifies one or more layer 3 information. 38. The method of claim 37, further comprising utilizing the switch to generate and associate a different attribute portion with a copy of the payload portion generated by the switch. 38. The method of claim 37, wherein utilizing the switch to duplicate at least the payload portion comprises duplicating only the payload portion of the data unit. 43. The method of claim 41, wherein associating different attribute portions with the data unit and the copy of the payload portion using the switch identifies different destination information between the copies of the payload portion. A method comprising a step. 38. The method of claim 37, wherein the step of duplicating using the switch includes duplicating the payload and the attribute using the switch. 42. The method according to claim 41, wherein generating and associating different attribute parts using the switch comprises changing a destination IP address. 46. The method of claim 45, wherein the step of changing the destination IP address comprises changing the destination IP address to an IP address corresponding to one or more terminals for which access to the payload portion is enabled. A method including a step of changing to an address. 38. The method of claim 37, wherein utilizing the data unit comprises audio content. 38. The method of claim 37, wherein the data unit includes video content. 38. The method of claim 37, wherein the data units include media to be streamed. 38. The method of claim 37, further comprising receiving a request to receive the stream of data units from at least one of the two or more requesting terminals. 51. The method of claim 50, wherein utilizing the switch to enable access to the payload portion of the data unit comprises accessing the at least one requesting terminal in response to the request. A method comprising the steps of: The method of claim 50, wherein the request is received from a device other than the terminal. A first communication interface configured and arranged to receive a stream of one or more data units, each including a payload portion and an attribute portion;
A buffer configured and arranged to store at least the payload portion of the data unit included in the received stream;
A replicator configured and arranged to replicate at least the payload portion of one or more of the data units;
A second communication interface configured and arranged to allow access by two or more terminals to the payload portion duplicated by the replicator,
A switch comprising: 54. The switch of claim 53, wherein the data unit comprises an Internet Protocol packet. 54. The switch of claim 53, wherein the attribute of a data unit specifies one or more layer 3 information. 54. The switch of claim 53, further comprising a processor configured and arranged to generate and associate a different attribute portion with the payload portion duplicated by the replicator. 57. The switch of claim 56, wherein the processor is configured and arranged to specify different destination information between different replicated versions of the payload portion. 57. The switch of claim 56, wherein the processor is configured and arranged to change a destination IP address. 57. The switch of claim 56, wherein the processor sets the destination IP address,
A switch configured and arranged to change to an IP address corresponding to the terminal that is enabled to access the payload using the second communication interface. 54. The switch of claim 53, wherein the replicator is configured and arranged to duplicate the payload portion and the attribute portion. 54. The switch of claim 53, wherein the data unit includes audio content. 54. The switch of claim 53, wherein the data unit includes video content. 54. The switch of claim 53, wherein the data units include media to be streamed. 54. The switch of claim 53, further configured and arranged to receive a request to receive the stream of data units from at least one requesting terminal of the two or more terminals. A switch with an interface. 65. The switch of claim 64, wherein said second communication interface is configured and arranged to allow said at least one requesting terminal to access said payload portion in response to said request. . 65. The switch according to claim 64, wherein the requester includes a device other than the terminal. 54. The switch of claim 53, wherein the second communication interface transmits the duplicated data unit stream to two different terminals. 68. The switch of claim 67, wherein the two different terminals receive the stream of data units at two different time intervals. 54. The switch of claim 53, to enable a first terminal to receive the stream of data units at a different point of the stream of data units from a second terminal. A switch wherein the replicator includes two or more pointers to the contents of the buffer. The switch of claim 53, wherein the buffer includes two or more instances of the stream of data units. 54. The switch of claim 53, wherein the replicator is configured and arranged to duplicate only the payload portion of the data unit. A method for receiving a stream of replicated data units, comprising:
Interfacing with a network that includes a switch that can replicate the stream of data units and make the replicated stream of data units accessible to two or more terminals;
Receiving the stream of data units from the switch, wherein each of the data units in the stream includes a payload portion and an attribute portion duplicated by the switch;
A method that includes 73. The method of claim 72, further comprising generating a perceptible output based on the stream of data units. The method of claim 72, wherein the attribute portion of the data unit includes an IP header. 73. The method of claim 72, wherein the attributes of the data unit specify one or more layer 3 information. 73. The method of claim 72, wherein the data units include audio content. 73. The method of claim 72, wherein the data units include video content. 73. The method of claim 72, wherein the data units include streamed media. 73. The method of claim 72, further comprising generating a request to receive the stream of data units. 80. The method of claim 79, wherein the payload portion of the data unit is received in response to the request. A method of delivering a data unit to a device, comprising:
Interfacing with a network including one or more switches capable of replicating at least the payload portion of the data unit in the stream of data units including the attribute portion and the payload portion;
Transmitting a stream of the data units to the switch to duplicate at least the payload portion of the data units in the stream for transmission to two or more terminals;
A method that includes The method of claim 81, wherein the data units include audio content. The method of claim 81, wherein the data units include video content. 83. The method of claim 81, wherein the data units include streamed media. The method of claim 81, wherein the attribute portion of the data unit includes an IP header. The method of claim 81, wherein the attribute portion of the data unit specifies one or more layer 3 information. First communication interface means for receiving a stream of one or more data units including a payload portion and an attribute portion;
Buffer means for storing at least the payload portion of the data unit included in the received stream;
Replicator means for replicating at least the payload portion of one or more of the data units;
Second communication interface means for enabling access by two or more terminals to the payload portion duplicated by the replicator,
A switch comprising: A source system configured and arranged to allow access to the stream of data units;
Arranged and arranged to receive a stream of data units from a source system, duplicate at least a payload portion of the data unit of the stream, and transmit the duplicated payload portion to two or more terminals Switches and
One or more terminals configured and arranged to receive a stream of data units duplicated by the switch;
A system comprising:

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