WO2004004284A1 - Framework for channelized voice using sdsl - Google Patents
Framework for channelized voice using sdsl Download PDFInfo
- Publication number
- WO2004004284A1 WO2004004284A1 PCT/US2002/028721 US0228721W WO2004004284A1 WO 2004004284 A1 WO2004004284 A1 WO 2004004284A1 US 0228721 W US0228721 W US 0228721W WO 2004004284 A1 WO2004004284 A1 WO 2004004284A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- voice
- channel
- drr
- sdsl
- exec
- Prior art date
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Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L12/00—Data switching networks
- H04L12/02—Details
- H04L12/16—Arrangements for providing special services to substations
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
- H04L65/80—Responding to QoS
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L65/00—Network arrangements, protocols or services for supporting real-time applications in data packet communication
- H04L65/1066—Session management
- H04L65/1069—Session establishment or de-establishment
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M11/00—Telephonic communication systems specially adapted for combination with other electrical systems
- H04M11/06—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors
- H04M11/062—Simultaneous speech and data transmission, e.g. telegraphic transmission over the same conductors using different frequency bands for speech and other data
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/22—Arrangements for supervision, monitoring or testing
- H04M3/26—Arrangements for supervision, monitoring or testing with means for applying test signals or for measuring
- H04M3/28—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor
- H04M3/30—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop
- H04M3/302—Automatic routine testing ; Fault testing; Installation testing; Test methods, test equipment or test arrangements therefor for subscriber's lines, for the local loop using modulation techniques for copper pairs
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04M—TELEPHONIC COMMUNICATION
- H04M3/00—Automatic or semi-automatic exchanges
- H04M3/18—Automatic or semi-automatic exchanges with means for reducing interference or noise; with means for reducing effects due to line faults with means for protecting lines
Definitions
- This invention relates to a framework for the definition of channelized voice transport over the SDSL physical layer.
- the framework builds upon the use of the dual-bearer TPS-TC and identifies the other processing elements to enable a channelize voice application.
- POTS communications includes not only the transmission of voice information, but also PSTN (public switched telephone network) modem information, control signals, and other information that is transmitted in the POTS bandwidth, which extends from approximately 300 hertz to approximately 3.4 kilohertz.
- PSTN public switched telephone network
- the descriptor "x" preceding the DSL designator is used to broadly denote a variety of DSL services, including SDSL, ADSL, RADSL, HDSL, etc.
- xDSL transmissions are sent to customer premises over the same twisted pair cabling as POTS transmission are sent. Since xDSL transmissions are communicated in a frequency band that is separate and distinct from the POTS frequency band, transmitting both types of signals over the same cabling (even at the same time), generally is not a problem.
- the POTS frequency band is defined between approximately DC and approximately 4 kHz
- xDSL frequency bands (although they vary depending upon the specific service) are generally defined by a lower cutoff frequency of approximately 26 kHz, and an upper cutoff frequency that depends upon the particular xDSL service.
- DRR dynamic rate repartitioning
- Embodiments of the invention incorporate use of a dual bearer framing mode for transport of simultaneous bit synchronous channelized voice and asynchronous data.
- voice block processing may be implemented to defines the framing for the channelized voice application.
- a Z bit channel is defined in the bit synchronous bearer for the purpose of signaling in support of dynamic rate repartitioning (DRR).
- This Z-bit channel may have a capacity of 8 kb/s.
- a bit synchronous PCM time slots may be transmitted in order of identification number (i.e., the PCM channels are ordered according to call control signaling events as illustrated in Figures 4A-4B).
- PCM samples may be presented to the bit synchronous channel and are not to be multiplexed together with other non-PCM data.
- Figure 1 is a schematic illustration of a reference model to define the processing elements in support of transporting synchronous PCM voice channels simultaneously with a data channel according to some embodiments of the invention.
- Figure 2 is a schematic illustration of a dual-bearer IFS-IC framing mode for support of channelized voice according to some embodiments of the invention.
- Figure 3 is a schematic illustration of a recommended framing as defined by a voice- processing block according to some embodiments of the invention.
- Figure 4A shows voice channel identification via voice processing block 106 according to some embodiments of the invention.
- Figure 4B shows transmission of the time slots resulting from various DRR commands according to some embodiments of the invention.
- Figure 5A is another schematic representation of the payload block of Figure 3 according to some embodiments of the invention.
- Figure 5B is a schematic chart showing possible definitions of the Z-bit channel throughout the superframe according to some embodiments of the invention.
- Figure 6 is a schematic representation of a definition for a DRR Control Byte according to some embodiments of the invention.
- Figure 7 is a schematic representation of a DRR Channel ID Byte according to some embodiments of the invention.
- Figure 8 is a schematic chart representing potential DRR commands according to some embodiments of the invention.
- Figure 9 is a schematic DRR signal flow diagram under normal operation executing a
- FIG. 10 is a schematic of the associated timing diagram for a typical execution of a
- DRR event according to some embodiments of the invention.
- Figure 1 shows a reference model to define the processing elements in support of transporting synchronous PCM voice channels simultaneously with a data channel according to some embodiments of the invention.
- the core modem may be based on SDSL, PMS-TC, and PMD definitions.
- To provide simultaneous PCM voice and data it may be desirable to provide a dual bearer TPS-TC, where one bearer carries the bit synchronous PCM voice channels and the other bearer carries the asynchronous data channel.
- system 100 may comprise processing elements at one or more office units 102 and at one or more customer premises 104.
- Office unit 102 may provide voice processing 106 to process voice signals from one or more voice networks 108.
- data processing 110 may be provided to process signals from one or more data networks 112.
- Dual bearer TPS-TC processing 114 and PMS-TC and PMD processing 1 16 may be provided at the office unit 102 and dual bearer TPS-TC processing 118 and PMS-TC and PMD processing 120 may be provided at the customer premises unit 104.
- Customer premises unit 104 may also comprise voice processing 122 in communication with one or more telephone devices 124 and data processing 126 in communication with one or more computer devices 128.
- Voice processing 106 in Figure 1 may define the framing structure of the PCM voice channels and the signaling channel.
- Voice channels may be provisioned statically or dynamically. With static provisioning, the required number of time slots are determined and set at initialization and are transported in the bit synchronous bearer channel. If a voice channel is active, the timeslot carries PCM voice samples; if the voice channel is inactive, the timeslot carries dummy data.
- the PCM timeslot may be activated and deactivated on an as needed basis.
- the supporting bandwidth is allocated in the bit synchronous bearer channel.
- the asynchronous bearer channel uses the remaining bandwidth in support of the data application.
- the voice timeslot becomes deactivated, the corresponding bandwidth is removed from the bit synchronous bearer and allocated to the asynchronous data bearer.
- the overall line bit rate stays the same.
- the voice processing 106 may initiate the dynamic rate repartitioning (DRR) commands to the dual-bearer TPS-TC 114.
- DRR dynamic rate repartitioning
- data processing 1 10 provides the data channel interface to the dual-bearer TPS-TC 1 14, which then multiplexes the two bearer channels for transport over the SDSL core modem.
- a recommended dual-bearer framing mode for support of channelized voice is shown in Figure 2.
- the first bearer i.e. bits l a through k sa
- the channelization structure within this bearer channel may be defined specifically for the voice application.
- each Payload Sub-Block may be split between two separate TPS-TC instances.
- the TPS-TC modes may be negotiated independently in a pre- activation communication channel (PACC) and there may be no direct interaction between them.
- PACC pre- activation communication channel
- TPS-TC a may be assigned the first k sa bits of each payload block, and TPS-T , may be assigned the last k sb bits of each payload bock.
- the k s bits assigned to it may be treated as if they constituted a complete Payload Sub-Block, and appropriate framing may be applied.
- the line clock may be frequency locked to the clock of the bit synchronous bearer.
- the synchronous bearer channel may be the reference channel for determining the stuff/delete operations.
- Embodiments of the invention may vary according to the set of technical requirements for the implementation of dynamic rate repartitioning (DRR).
- DRR dynamic rate repartitioning
- the use of a TPS-TC signaling channel using a dedicated Z-bit signaling channel allows for a robust and reliable implementation of DRR. Consequently, in each voice frame, one bit called the Z-bit may be allocated for transport of TPS-TC signaling between the central office 102 and customer premises 104 SDSL units. It is this channel that may transport the commands in support of DRR.
- the equivalent bit rate for the Z-bit channel is 8 kb/s.
- Figure 3 is a schematic of recommended framing as defined in the voice-processing 106 according to some embodiments of the invention.
- the one bit Z-bit is indicated at 302.
- M bits may be allocated for the signaling channel 304, which transports the signaling information between customer premises unit 104 and the network in support of the voice service.
- the equivalent bit rate for the signaling channel is M*8 kb/s.
- the following remaining bits 306, 308, 310, 312 may carry the active PCM voice channels, where each channel contains 8 bits for an equivalent bit rate of 64 kb/s per voice channel. Up to N voice channels may be supported, where the value of N is any suitable value.
- Z-bit 302 and voice signaling channel bits 304 are transmitted every frame.
- the time slots 306-312 may be arranged in order of increasing identification number.
- Figures 4A-4B show an example of the arrangement of the PCM voice channel timeslots per DRR event or action.
- Figure 4A shows voice channel identification via voice processing block 106 according to some embodiments of the invention (a similar figure may be drawn for voice processing block 122). If no voice channels are active, then the Z 302 and Signaling 304 channels are transmitted; no time slot bits 306-312 are transmitted. The remainder of the line bit rate is allocated to the asynchronous data channel.
- Figure 4B shows transmission of the time slots resulting from various DRR commands according to some embodiments of the invention. As shown in Figure 4B, the time slots may be transmitted in order of identification number.
- embodiments of the invention implement a one-bit Z-channel, at 8 Kbps, that is dedicated to the DRR protocol operation.
- This DRR protocol may be modeled as being exchanged between the TPS-TC in a line termination unit and the TPS-TC in the network termination unit.
- FIG. 5 A is another schematic representation of the payload block of Figure 3 according to some embodiments of the invention.
- a single Z-bit e.g., 302, 502
- a total of 48 bits, or six bytes, per SDSL super-frame may be dedicated to transferring the DRR protocol.
- the Z-bit is represented as DRR(n) bit (item 502).
- Signaling block 504 may comprise M bits
- STM data 506 may comprise 8*N bits
- ATM data 508 may comprise 8*K bits.
- FIG. 5B is a schematic chart showing possible definitions of the Z-bit channel throughout the superframe according to some embodiments of the invention.
- the 48 block per SDSL superframe may comprise 48 DRR bits or 6 DRR bytes (i.e., one DRR bit per data block).
- the DRR Control Byte may be duplicated three times per SDSL super-frame (e.g., copy 1 to copy 3).
- the DRR Channel ID Byte which may carry the activated/deactivated time slot status information on each PCM voice channel, may be duplicated three times (copy 1 to copy 3).
- the correct DRR Control Byte and DRR Channel ID Byte data per super-frame may be calculated using a 2 of 3 majority algorithm.
- This approach enables a relatively robust DRR protocol. For example, if the SDSL frame is affected by a cyclic redundancy check (CRC) alarm, the recipient can still examine the three copies of the DRR Control Byte and DRR Channel ID Byte and determine the true value based upon an assessment of whether 2 of 3 copies agree.
- CRC cyclic redundancy check
- FIG 6 is a schematic representation of a definition for a DRR Control Byte according to some embodiments of the invention.
- DRR Command 602 may comprise one or more of the supported 16 DRR commands, four of which are defined and listed in Figure 8.
- Sequence Number (SN) 604 may comprise a field that may be used as an error control mechanism that indicates when there is a loss of a DRR message (e.g., due to a CRC error). As discussed below, a value for a MONITOR command may be set to "00". In some embodiments, Sequence Number 604 may count from “01" to "1 1" during an exchange of EXEC and EXEC_ACK/EXEC_NAK commands between the line terminal (LT) and the network terminal (NT).
- Time Slot ID Group (s) 606 may comprise a field that is used when the SDSL supports more than 8 voice channels. These two bits may be used to indicate which . particular timeslot belonging to the group of 8 voice-channels that the DRR Command is affecting. The 's' value may be between 0 ("00") and 3 ("11"). With this structure, up to 32 time slots may be supported.
- the related voice channel is enabled (i.e., currently active with a voice call, or the PCM channel is in the process of being established for a new voice call. If the bit value is a '0', the related voice channel is disabled (i.e., this PCM channel is no longer supporting a voice call, and this bandwidth is no available for asynchronous data).
- Figure 8 is a schematic chart representing potential DRR commands according to some embodiments of the invention. Other commands are possible.
- Figure 9 is a schematic DRR signal flow diagram under normal operation executing a DRR event according to some embodiments of the invention.
- Figure 10 is a schematic of the associated timing diagram for a typical execution of a DRR event according to some embodiments of the invention.
- down stream voice channel may change the time slot mapping at the SF(n+7) super-frame after three contiguous EXEC command and any EXEC_ACK is received.
- up stream voice channel may change the time slot mapping at the SF(m+5) super-frame after a third EXEC_ACK command.
- the longest delay for NT to respond to the EXEC command is almost one superframe.
- the LT to receive the last response from the NT, three superframes may be needed.
- a downstream path to change the voice time slot may occur at the seventh superframe from the EXEC_1 command.
- An upstream change to the voice channel time slot may occur at the superframe that is after the EXEC_ACK_3 command.
- Other configurations are possible.
- the protocol description below references Figures 9-10.
- a voice channel activation and deactivation may be initialized by the "EXEC" DRR command from LT side, downstream direction.
- the "EXEC" DRR command may be sent in three successive SDSL frames with the related channel byte information to which the EXEC command applies. More than one voice channel within the Time Slot ID Group can be handled at the same time.
- the voice channels will be activated or deactivated in the subsequent 4 th super- frame, downstream direction.
- the "SN" number may be used for the "EXEC” DRR command counter from “01", “10", to "1 1" in successive frames.
- each copy of the "EXEC” DRR command contains the same "SN" number.
- the receiver for every SDSL super-frame, the receiver, NT, must send an "EXEC ACK” or ⁇ XEC NAK” DRR command back to the LT when the command is not MONITOR, check the SN number and command fields.
- the procedures for coding the SN as described above may also apply to the "EXEC_ACK” or "EXEC_NAK” DRR commands.
- the NT receiving a frame that contains a DRR command may use a 2-out-of-3 majority algorithm to figure out the correct voice channel to activate/deactivate. Of the three frames containing the same DRR command (where the SN is incremented by one each time), if there is only one correct DRR command received, the NT should still change the voice channel status at the end of EXEC command based on the SN number to figure out the correct super-frame number.
- the upstream voice channel activation/de-activation is done after three EXEC_ACK EXEC_NAK, if there is at lease one EXEC_ACK command as described above. If no correct DRR command is received, the NT may maintain the current voice channel status. The procedures associated with the MONITOR command may also still apply. If there is some data error, it will be recovered from by the LT on the next EXEC command.
- the LT side may decide to re-issue the same DRR command based on the EXEC_ACK, and EXECJNAK commands received. However, voice channel activations and deactivations in the downstream direction should always be executed after transmitting the "EXEC" DRR command three times.
- EXECACK/EXEC_NAK should be the same as the received "EXEC" DRR commands.
- the LT side may be based on the EXEC_ACK return command to figure out whether the voice channel activation or deactivation command is complete.
- the DRR commands are typically issued from LT to NT.
- the MONITOR command should be issued.
- the SN number may be set to "00" for MONITOR command.
- the MONITOR command may be used on an ongoing basis (unless DRR commands need to be exchanged) to send the voice channel byte/time slot byte to maintain the correct voice channel activation or deactivation status on either side of the SDSL.
- Step one is to exchange an updated list of timeslot assignments between the LT and the NT by using the B Channel Allocate and B Channel Allocate Ack messages. These messages may be carried over the SDSL embedded operations channel (eoc).
- Step two is to accomplish the subsequently transition to frames with the new time slot allocation by an exchange of messages between the LT and the NT which are defined by SDSL overhead (SOH) bits.
- SOH SDSL overhead
- the switch to the new SDSL frames occurs after the Exec Ack (or Exec Ack New) and Exec Complete messages are successfully exchanged.
- the first new upstream or downstream SDSL frame after a successful repartition contains the Done message. In other words, this exchange of SOH messages constitutes exchanging DRR signaling between the TPS-TC process.
- T re f It is useful to establish a reference time T re f to define the time required to transition to frames with the new timeslot allocation.
- T re f may be measured as the interval between the LT sending the Sync Demand and the Sync Confirm.
- the parameter n may be defined by the hand-shaking procedure.
- each message will require five bytes for transmission (assuming no more than eight PCM voice channels).
- the eoc is typically a slow speed channel (about 3.3 kbps) due to the fact that only 20 bits are allocated to the eoc in each SDSL superframe. Assuming no eoc processing delays at either the LT or the NT, it will take 4 - 8 superframes, or 24 - 48 ms, to exchange the B
- the eoc also carries other traffic with the requirement that the maximum length of a frame is 75 octets. Since the B Channel Allocate and B Channel Allocate Ack messages support voice traffic, they should be given a higher priority for processing over management events that are not time critical. Unfortunately, the eoc does not have such a queuing mechanism. Consequently, the B Channel AllocatelAck messages could get queued up behind other messages before it can be transmitted. This could add substantial delay to the time that is required just to transmit the messages across the eoc.
- a CRC is generated for each SDSL frame and is transmitted on the following frame. All bits in the frame except the synchronization word, CRC bits, and the stuff bits are covered by the CRC. If a CRC anomaly is declared, the entire frame is discarded, which includes the SOH messages of Step two above.
- the LT may periodically transmit the B Channel Allocate message to the NT as a means of checking the status of the voice timeslots. This can be used to ensure that the NT is in sync with the LT, and it can be done during periods of time when voice channels are not being established or cleared.
- POTS and ISDN timeslots may be temporarily allocated to the ATM bearer part of the SDSL frame without changing their slot position. However, this may be inconsistent with positions being taken in other proposals for standards. For example, in the VoDSL Working Group of the DSL Forum and in ITU-T Q4/SGI5 the voice bearer timeslots and the ATM bearer part are grouped together.
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Abstract
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Priority Applications (4)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2004517489A JP2005520464A (en) | 2001-09-10 | 2002-09-10 | Framework for channelized voice using SDSL |
KR10-2004-7003583A KR20040033306A (en) | 2001-09-10 | 2002-09-10 | Framework for channelized voice using sdsl |
AU2002368011A AU2002368011A1 (en) | 2001-09-10 | 2002-09-10 | Framework for channelized voice using sdsl |
EP02807516A EP1442584A1 (en) | 2001-09-10 | 2002-09-10 | Framework for channelized voice using sdsl |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US31845801P | 2001-09-10 | 2001-09-10 | |
US60/318,458 | 2001-09-10 |
Publications (1)
Publication Number | Publication Date |
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WO2004004284A1 true WO2004004284A1 (en) | 2004-01-08 |
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ID=30000320
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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PCT/US2002/028721 WO2004004284A1 (en) | 2001-09-10 | 2002-09-10 | Framework for channelized voice using sdsl |
Country Status (5)
Country | Link |
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EP (1) | EP1442584A1 (en) |
JP (1) | JP2005520464A (en) |
KR (1) | KR20040033306A (en) |
AU (1) | AU2002368011A1 (en) |
WO (1) | WO2004004284A1 (en) |
Cited By (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1842303A2 (en) * | 2005-01-26 | 2007-10-10 | AT&T Knowledge Ventures, L.P. | System and method of managing digital data transmission |
Citations (2)
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EP0924896A1 (en) * | 1997-12-17 | 1999-06-23 | Hewlett-Packard Company | Communicating isochronous and asynchronous data |
US5943344A (en) * | 1997-05-14 | 1999-08-24 | Telefonaktiebolaget L M Ericsson | Method and apparatus for formatting synchronous and asynchronous data |
-
2002
- 2002-09-10 WO PCT/US2002/028721 patent/WO2004004284A1/en not_active Application Discontinuation
- 2002-09-10 AU AU2002368011A patent/AU2002368011A1/en not_active Abandoned
- 2002-09-10 KR KR10-2004-7003583A patent/KR20040033306A/en not_active Application Discontinuation
- 2002-09-10 JP JP2004517489A patent/JP2005520464A/en active Pending
- 2002-09-10 EP EP02807516A patent/EP1442584A1/en not_active Withdrawn
Patent Citations (2)
Publication number | Priority date | Publication date | Assignee | Title |
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US5943344A (en) * | 1997-05-14 | 1999-08-24 | Telefonaktiebolaget L M Ericsson | Method and apparatus for formatting synchronous and asynchronous data |
EP0924896A1 (en) * | 1997-12-17 | 1999-06-23 | Hewlett-Packard Company | Communicating isochronous and asynchronous data |
Non-Patent Citations (3)
Title |
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COHEN R: "An efficient scheme for accommodating synchronous traffic in a cable-modem network while avoiding segmentation of asynchronous packets", COMPUTER COMMUNICATIONS, ELSEVIER SCIENCE PUBLISHERS BV, AMSTERDAM, NL, vol. 22, no. 5, 15 April 1999 (1999-04-15), pages 399 - 410, XP004164516, ISSN: 0140-3664 * |
ETSI: "Transmission and Multiplexing (TM); Access transmission system on metallic access cables; Symmetrical single pair high bitrate Digital Subscriber Line (SDSL) - TS 101 524 v1.1.2", ETSI TECHNICAL SPECIFICATION, August 2001 (2001-08-01), Sophia Antipolos Cedex, France, EU., pages 1 - 125, XP002231960 * |
THE ATM FORUM TECHNICAL COMMITTEE: "Specification of (DBCES) dynamic bandwidth utilization - in 64Kbps time slot trunking over ATM - using CES - AF-VTOA-0085.000", THE ATM FORUM TECHNICAL COMMITTEE, July 1997 (1997-07-01), Mountain View, CA, USA., pages 1 - 26, XP002232371, Retrieved from the Internet <URL:ftp://ftp.atmforum.com/pub/approved-specs/af-vtoa-0085.000.pdf> [retrieved on 20030224] * |
Cited By (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
EP1842303A2 (en) * | 2005-01-26 | 2007-10-10 | AT&T Knowledge Ventures, L.P. | System and method of managing digital data transmission |
EP1842303A4 (en) * | 2005-01-26 | 2009-03-04 | At & T Knowledge Ventures Lp | System and method of managing digital data transmission |
US8154995B2 (en) | 2005-01-26 | 2012-04-10 | At&T Intellectual Property I, L.P. | System and method of managing digital data transmission |
Also Published As
Publication number | Publication date |
---|---|
EP1442584A1 (en) | 2004-08-04 |
KR20040033306A (en) | 2004-04-21 |
AU2002368011A1 (en) | 2004-01-19 |
JP2005520464A (en) | 2005-07-07 |
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