Multiplex communications – Pathfinding or routing – Combined circuit switching and packet switching
Reexamination Certificate
2000-04-07
2004-02-03
Jung, Min (Department: 2663)
Multiplex communications
Pathfinding or routing
Combined circuit switching and packet switching
C370S395610, C370S522000
Reexamination Certificate
active
06687244
ABSTRACT:
BACKGROUND
At present, Asynchronous Transfer Mode (ATM) technology is being used to provide high speed transport for traffic carried by older transport formats such as DS
1
and DS
0
. This ATM transport technique uses an ATM interworking multiplexer (ATM mux) to convert telecommunications traffic from the older formats into ATM cells that can be transported over broadband connections. At the terminating end of the broadband system, the ATM cells are re-converted back into the older format by another ATM mux for delivery to the older transport system.
Many older transport formats require the transmission of a continuous signal even when no user traffic is being transported. For example, a DS
0
connection continuously transmits a 64,000 bit/second signal whether or not the DS
0
connection is transporting any user traffic. This causes a problem in the above-described transport scenario. The ATM mux will convert the DS
0
signal into ATM cells for transport, and since the DS
0
signal is continuous, a continuous stream of ATM cells must be transported by the ATM network. This occurs even when no user traffic is being transported. The idle DS
0
signal is still transported in empty ATM cells. Methods to detect these idle continuous signals that do not transport user information have included analyzing information samples from the continuous signals to detect idle codes. However, these idle codes may be emulated by user information such as voice or data. This causes problems when trying to determine whether or not a signal carries user information.
The current situation represents a waste of resources. At present, there is a need for an ATM system that can transport continuous signal formats when they carry user traffic, but not when they do not carry user traffic.
SUMMARY
The invention includes an asynchronous transfer mode (ATM) system for transporting user information in ATM cells. The ATM cells contain a virtual path identification/virtual channel identification (VPI/VCI). The user information is from a continuous-signal transport system that produces telecommunications signaling related to the continuous signal. The continuous signal is associated with the VPI/VCI.
The system comprises a processor and ATM interworking multiplexer. The processor receives telecommunications signaling and detects, based on the telecommunications signaling, when the continuous signal is transporting user information and when the continuous signal is not transporting user information. The processor associates the continuous signal with the VPI/VCI. The processor also provides a control instruction to enable the VPI/VCI when the continuous signal is transporting user information, and provides a control instruction to disable the VPI/VCI when the continuous signal is not transporting user information.
The ATM interworking multiplexer is coupled to the processor. The ATM interworking multiplexer receives the continuous signal and associates it with the VPI/VCI. The ATM interworking multiplexer receives the control instructions from the processor and generates and transmits ATM cells containing the VPI/VCI and the user information in response to the enabling control instruction. The ATM interworking multiplexer stops generating and transmitting ATM cells containing the VPI/VCI in response to the disabling control instruction.
The invention has many variations. The telecommunications signaling protocol could by Signaling System #
7
. The processor might use an SS
7
Initial Address Message (IAM) to detect when the continuous signal transports user information. The processor might use a Circuit Identification Code (CIC) in the SS
7
IAM to identify the continuous signal and to associate the continuous signal with the VPI/VCI. The processor might use a an SS
7
Release message (REL) or Release Complete message (RLC) to detect when the continuous signal no longer transports user information.
The invention might include a Signal Transfer Point (STP) that is linked to the processor and that transfers telecommunications signaling to the processor. The STP might transfer copies of Signaling System #
7
(SS
7
) message routing labels to the processor. The STP might transfer copies of SS
7
Initial Address Message (IAM), Release message (REL), or Release Complete message (RLC) routing labels to the processor. The STP might transfer copies of SS
7
routing labels to the processor that have particular Originating Point Codes (OPCs) and Destination Point Codes (DPCs).
The ATM interworking multiplexer might receive a continuous DS
3
signal or a continuous DS
1
signal. The ATM interworking multiplexer might transmit the ATM cells over a SONET connection. In some embodiments, the ATM interworking multiplexer supports multiple signals. Individual VPI/VCIs would correspond to individual continuous signals. The ATM interworking multiplexer would include: a continuous signal interface to receive the continuous signals, an ATM Adaption Layer (AAL) to convert the continuous signals into ATM cells with corresponding VPI/VCIs, an ATM interface to transmit the ATM cells, and a control interface to receive the control instructions and control the AAL to generate and transmit cells with enabled VPI/VCIs and to stop the generation and transmission of ATM cells with a disabled VPI/VCIs.
The invention provides the advantage of having the ATM system only transport cells that actually carry user information. Cells containing the continuous signal, but no user information are not transmitted. This provides for efficient allocation and use of bandwidth in the ATM system.
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Jung Min
Sprint Communications Company L.P.
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