Multiplex communications – Fault recovery
Reexamination Certificate
1997-04-24
2001-10-02
Marcelo, Melvin (Department: 2663)
Multiplex communications
Fault recovery
C370S535000
Reexamination Certificate
active
06298038
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention is directed to a configuration for a transport node of a telecommunication system, and more particularly, to a transparent multiplexer for telecommunication systems.
2. Background Art
Telecommunications network providers are feeling the pressure of modern technologies as users demand ever more capacity. That factor, along with the reality of fiber congestion in the network, is causing service providers to search for a solution that will increase capacity without forcing them to deploy additional fibers. At the moment, two practical solutions exist: using wavelength division multiplexing (WDM) to combine multiple wavelengths on one set of fibers, or using a higher bit rate, time division multiplexing (TDM) systems.
Both solutions are viable, but each has disadvantages for certain applications. Linear systems have a different solution than rings, short spans have a different solution than long spans in each type of network, and even rings will have different solutions from one another, depending on the number of the nodes and the span lengths between the nodes.
In practice, there are many benefits to large bandwidths on a single SONET network element, especially in ring topologies. Network management can be simplified by reducing the number of network elements (NE). This also reduces the amount of equipment in the network, which means fewer trips to a location for equipment repairs and replacement.
For an existing linear system that is experiencing fiber exhaust on a given span, the traditional solution is to replace the relevant terminals to obtain a higher line rate system. However, for a ring configuration, the line rate of the entire ring must be upgraded even if only one span is short of fiber. It is thus easy to understand why some network providers are asking for other options.
SUMMARY OF INVENTION
Transparent transport is defined as the ability to provide continuity of all payloads and associated overhead bytes necessary to maintain a lower bit rate linear or ring system through a higher bit rate midsection. The lower bit rate linear or ring system shall operate as if it were directly connected without the higher bit rate midsection.
It is an object of the present invention to provide a configuration for a telecommunication system and a method for addressing the fiber exhaust on a per span basis, without having to replace the equipment of all tributary (trib) systems. With this invention, an entire ring system does not have to be upgraded to a higher line rate due to fiber exhaust on a single span. The invention is particularly applicable to OC-48 rings, although lower rates rings, such as OC-12 and OC-3 may also be upgraded, as well as higher rates, when available.
It is another object of the present invention to provide a configuration for a telecommunication system that permits tributary channels to be carried transparently over a high rate line, with no change in provisioning of tributary systems. For example, the tributaries may be OC-48/OC-12/OC-3 lines and the high rate line could be an OC-192 line.
Still another object of this invention is to provide a supercarrier for transporting a plurality of trib systems over a midsection of a network. This is obtained by provisioning a pair of transparent multiplexer/demultiplexers (TMuxs) at the ends of the midsection, which manipulate the tribs such as to maintain the protection switching, to effect line maintenance signalling, section/line/path performance monitoring, and to provide sufficient performance information for fault isolation.
Accordingly, the invention comprises a method for transporting a plurality (K) of trib signals over a high rate span, comprising the steps of connecting a plurality (K) of trib input ports to a like plurality (K) of trib networks, each trib input port for receiving a trib input signal from a corresponding trib network over a trib channel, transparently multiplexing all the trib input signals into a supercarrier signal, the supercarrier signal comprising operation, administration, maintenance and provisioning (OAM&P) information on all the trib input signals and OAM&P information on the supercarrier signal, and connecting a supercarrier output port to the high bit rate span for transmitting the supercarrier signal.
The invention further comprises a method for transporting a plurality (K) of trib signals over a high bit rate span, comprising the steps of connecting a supercarrier input port to the high rate span for receiving a supercarrier signal over a supercarrier channel, transparently demultiplexing the supercarrier signal into a plurality (K) of trib output signals, each the trib output signal comprising OAM&P information on the trib output signal and OAM&P information on the supercarrier signal, and connecting a plurality (K) of trib output ports to a like plurality of trib networks, each trib output for transmitting a trib output signal over a corresponding trib channel.
Further, in a plurality (K) of tributary networks, each trib network for transporting trib signals between a multitude of sites with protection switching capabilities, the trib networks having in common a first and a second site, a method for carrying all the trib signals between the first and the second site over a high rate span, with no change to the provisioning of the trib networks, the method comprising, at any of the first or the second site, the steps of providing a like plurality (K) of trib ports and connecting each the trib port to a corresponding trib network over an associated FW trib channel, an associated FP trib channel, an associated RW trib channel and an associated RP trib channel, providing a supercarrier port and connecting same to the high rate span over a FW, a FP, a RW and a RP supercarrier channel, receiving at each trib port, from the corresponding trib network, a FW trib signal over the associated FW trib channel, and a FP trib signal over the associated FP trib channel, transparently multiplexing all the FW trib signals into a FW supercarrier signal comprising OAM&P information on all the FW trib signals and OAM&P information on the FW supercarrier signal, and transparently multiplexing all the FP trib signals into a FP supercarrier signal comprising OAM&P information on all the FP trib signals and OAM&P information on the FP supercarrier signal. The invention further comprises the steps of at the supercarrier port, transmitting the FW supercarrier signal over the FW supercarrier channel and transmitting the FP supercarrier signal over the FP supercarrier channel.
The invention further comprises a transparent multiplexer/demultiplexer (T-Mux) for a telecommunication system, comprising a multi-channel receiver for receiving a plurality (K) of trib input signals, each from an associated trib network, delineating each the trib input signal into a trib data signal and a trib OAM&P signal, means for multiplexing all the trib data signals into a supercarrier data signal, means for processing all the trib OAM&P signals and generating a supercarrier OAM&P signal, and a supercarrier transmitter for mapping the supercarrier data signal and the supercarrier OAM&P signal into an output supercarrier signal of a high bit rate, and transmitting same over a high rate span.
Further, a transparent multiplexer/demultiplexer (T-Mux) for a telecommunication system comprises a supercarrier receiver for receiving a supercarrier signal of a high bit rate over a high rate span channel and delineating same into a supercarrier data signal and a supercarrier OAM&P signal, means for demultiplexing the supercarrier data signal into a plurality (K) of trib data signals, means for processing the supercarrier OAM&P signal into a like plurality (K) of trib OAM&P signals, and a multi-channel transmitter for mapping each of the trib data signals and a corresponding one of the trib OAM&P signals into a trib signal and transmitting each the trib signal to an associated trib network.
A basic advantage of this invention is per span relief for fiber exhaust w
Armstrong Timothy James
Gagnon Ronald J.
Martin David Wright
Nicholson David John
Solheim Alan Glen
Diaconescu Aprilia U.
Lee Chiho Andrew
Marcelo Melvin
Nortel Networks Limited
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