Patent Abstract:
An apparatus comprising a time domain multiplexing (TDM) to Orthogonal Frequency Division Multiplexing (OFDM) or bounded Quadrature Amplitude Modulation (QAM) channels HOT PON converter configured to couple to an optical line terminal (OLT) via an optical fiber and to a plurality of network terminals (NTs) via a point-to-multipoint coaxial cable and configured to transmit TDM data from the OLT using OFDM or bounded QAM channels to the corresponding NTs, wherein the OFDM or bounded QAM channels transmission of TDM data maintains End-to-End (E2E) TDM passive optical network (PON) protocols, service provisioning, and quality of service (QoS).

Full Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     The present application claims priority to U.S. Provisional Patent Application 61/371,408, filed Aug. 6, 2010 by Yuxin Dai, and entitled “Hybrid Orthogonal Frequency Division Multiplexing Time Domain Multiplexing Passive Optical Network,” which is incorporated herein by reference as if reproduced in its entirety. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO A MICROFICHE APPENDIX 
     Not applicable. 
     BACKGROUND 
     Coaxial cable plants have been widely deployed worldwide, e.g., in the past two to three decades. Although Time Domain Multiplexing (TDM) Passive Optical Networks (PONs) based Fiber-to-the-home (FTTH) architecture are emerging, due to the relatively high cost of such systems, coaxial cable plants are still serving many broadband triple play customers today. The coaxial cable has about 5 Gigabit per second (Gbps) digital bandwidth, which is typically sufficient for broadband access demand. One problem of traditional cable access is that it may not have a satisfactory data access scheme that is sufficient for current or future users demand. For example, a data over cable service interface specification (DOCSIS) standard is used to provide data access in North America and Europe. The DOCSIS standard has an upstream data rate that is limited to about 100 Megabit per second (Mbps), such as in the case of DOCSIS 3.0 with channel bonding which is shared by many (e.g. from about 100 to about 500) cable modems. Due to historic reasons, e.g., to support legacy systems and/or save investment cost in new infrastructure, DOCSIS may still be used as a cable data access scheme in these regions in the foreseeable future. A TDM PON can provide much higher data rates than coaxial cable systems. For example an Ethernet PON (EPON) can provide about 1 Gbps upstream and downstream symmetric bandwidth to about 32 shared customers, and a GPON can support 2.5 Gbps downstream and 1.25 Gbps upstream bandwidth to about 32 shared customers. Thus, the TDM PON is a more attractive data access method for non-DOCSIS regions, such as Asia and China. 
     SUMMARY 
     In one embodiment, the disclosure includes an apparatus comprising a TDM to Orthogonal Frequency Division Multiplexing (OFDM) or bounded Quadrature Amplitude Modulation (QAM) channels HOT PON converter configured to couple to an optical line terminal (OLT) via an optical fiber and to a plurality of network terminals (NTs) via a point-to-multipoint coaxial cable and configured to transmit TDM data from the OLT using OFDM or bounded QAM channels to the corresponding NTs, wherein the OFDM or bounded QAM channels transmission of TDM data maintains End-to-End (E2E) TDM passive optical network (PON) protocols, service provisioning, and quality of service (QoS). 
     In another embodiment, the disclosure includes a network component comprising a receiver configured to receive TDM PON downstream data from an OLT and receive OFDM or bounded QAM upstream data from a plurality of NTs, a converter configured to remove TDM PON line coding and to encapsulate and convert the TDM PON downstream frames to OFDM or bounded QAMs downstream data and encapsulate and convert the OFDM or bounded QAMs upstream data to TDM PON upstream frames, and a radio frequency (RF) transmitter configured to send the OFDM or bounded QAMs downstream data to the corresponding NTs and an optical transmitter to send the TDM PON upstream data to the OLT. 
     In yet another embodiment, the disclosure includes a network apparatus implemented method comprising receiving a TDM optical signal from an OLT, processing with a processor the TDM optical signal to remove TDM PON line code and to extract TDM data in a TDM PON frame, processing with a processor to encapsulate TDM PON frame using OFDM or bounded QAM, and sending the OFDM or bounded QAM processed TDM PON frame to a plurality of NTs via a coaxial cable. 
     These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
         FIG. 1  is a schematic diagram of embodiments a TDM PON (EPON and/or GPON) based HOT PON. 
         FIG. 2  is a schematic diagram of another embodiment of an EPON based HOT PON. 
         FIG. 3  is a schematic diagram of an embodiment of a Gigabit PON (GPON) based HOT PON. 
         FIG. 4  is a schematic diagram of an embodiment of a combined EPON and GPON based HOT PON. 
         FIG. 5  is a schematic diagram of an embodiment of a HOT PON converter. 
         FIG. 6  is a schematic diagram of an embodiment of a HOT PON frame. 
         FIG. 7  is a schematic diagram of an embodiment of HOT PON communication channels. 
         FIG. 8  is a flowchart of an embodiment of a HOT PON data forwarding method. 
         FIG. 9  is a schematic diagram of an embodiment of a network unit. 
         FIG. 10  is a schematic diagram of an embodiment of a general-purpose computer system. 
     
    
    
     DETAILED DESCRIPTION 
     It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents. 
     Although TDM PON is considered a more advanced fiber access technology, coaxial cables are still widely used for last mile broadband access. The coaxial cable has substantially higher bandwidth than twist pair wires and has been widely deployed during the past two or three decades. Due to the relatively high cost of FTTH, fully utilizing the bandwidth of existing coaxial cable plants in conjunction with TDM PON technologies may be an economic way to meet the bandwidth demand today. 
     Extending at least some of the TDM PON services to existing coaxial cable plants may be desirable to obtain some of the advantages of TDM PON systems while maintaining at least some of the coaxial cable plant infrastructure. However, extending the TDM PON services to the coaxial cable plants may also be challenging. 
     Disclosed herein is a system and method for establishing a Hybrid OFDM TDM PON. The Hybrid OFDM TDM PON may extend the TDM PON protocols (e.g., for an EPON, Gigabit PON (GPON), or other PON types) to coaxial cables with relatively wideband OFDM technology or bounded QAM channels. As such, the TDM PON protocols, provisioning, QoS, and services may be seamlessly extended to the coaxial cable plants. The Hybrid OFDM TD PON may also provide a smooth migration path to FTTH in the future. The Hybrid OFDM TDM PON may also be referred to herein as a HOT PON. 
       FIG. 1  illustrates embodiments of a TDM PON (EPON and/or GPON) based HOT PON  120 . The HOT PON  120  may comprise a NGB aggregation network  121 , a plurality of EPON OLTs  122 , a plurality of HOT PON converter units  124 , and a plurality of network terminals (NTs)  128 . The EPON OLTs  122  may be coupled, e.g., at the edge, to the NGB aggregation network  121  and each EPON OLT  122  may be coupled to a corresponding HOT PON O/E unit  124  via an optical fiber  123 . Each HOT PON O/E unit  124  may be coupled to a plurality of NTs  128  via a coaxial cable plant  127 . The components of the HOT PON  120  may be arranged as shown in  FIG. 1 . 
     The HOT PON converter units  124  may be configured to extend EPON QoS and provisioning of the EPON over the coaxial cable plant  127  to the customer end, e.g., the NTs  128 . The HOT PON converter units  124  may implement an OFDM scheme or bounded QAM channels to extend TDM protocols and allow E2E QoS and provisioning from the EPON OLTs  122  to the NTs  128  and associated customers. The OFDM or bounded QAM scheme may be transparent to the PON protocol and is described in more detail below. The NTs  128  may be customer equipment configured to receive customer data, services, and/or system control data, from the corresponding HOT PON O/E units  124  via the coaxial cable plant  127  in electrical signal form. The NTs  128  may demodulate or process the received electrical signals to provide the data/services to the customers or end-users that are associated with the NTs  128 . The NTs  128  may also modulate and send data in the form of electrical signals from the customers (e.g., customer communication devices) to the HOT PON converter units  124  via the coaxial cable plant  127 . 
     In an embodiment, the data sent from EPON OLTs  122  may comprise Moving Picture Experts Group (MPEG) Single Program Transport Stream (SPTS), IP multicast, EPON control data or frames. The EPON frames may be processed based at the HOT PON converter units  124 . The data forwarded to the NTs  128  may comprise IP multicast, Ethernet, EPON control, and/or OFDM data or frames. The HOT PON  120  in  FIG. 1  is an EPON based HOT PON, however similar architectures may be used for other types of TDM PONs such as a GPON based HOT PON, as described further below. 
       FIG. 2  illustrates an embodiment of another EPON based HOT PON  200 . The EPON HOT PON  200  may comprise an EPON OLT  210 , a HOT PON converter  220 , and a plurality of EPON NTs  230 . The EPON OLT  210  may be coupled to the HOT PON converter  220  via a single fiber  215 . There is no optical splitter between the EPON OLT  128  and the HOT PON converter  220 . The HOT PON converter  220  may be coupled to the HOT PON NTs  230  via a point-to multiple point coaxial cable  225 . The components of the EPON HOT PON  200  may be configured similar to the corresponding components of the HOT PON  120 . The EPON HOT PON  200  may support up to about 32,768 logical EPON NTs  230 . 
     The EPON OLT  210  transmits data using the EPON protocol. The EPON OLT  210  may be located at a central office. The HOT PON converter  220  may convert EPON frames to the frequency domain that are transmitted in electrical (e.g., RF) signals over the coaxial cable  225 . The HOT PON converter  220  may encapsulate TDM PON Media Access Control (MAC) frames that are transmitted using electrical signals over the coaxial cable  225 . In the OFDM or bounded QAM scheme, different HOT PON NTs  230  may share frequency bands, but may not require time scheduling at the HOT PON converter  220 . The OFDM scheme or bounded QAM may be transparent to the TDM protocol at the EPON OLT  210  that may not be aware of the OFDM or bounded QAM scheme at the HOT PON converter  220 . The HOT PON converter  220  may be located in the field away from the EPON OLT  210 . 
     The fiber  215  between the EPON OLT  210  and the HOT PON converter  220  may not comprise any splitters and hence the fiber  215  may reach a longer distance than a standard 20 kilometers (km) PON distance. For example, the fiber  215  may carry the TDM PON signals a distance equal to about 70 km or more from the EPON OLT  210  to the HOT PON converter  220 . The HOT PON NTs  230  may then receive the RF signals that comprise the TDM PON MAC frames and services. The HOT PON NTs  230  may be EPON ONTs with optical transceivers replaced by electrical transceivers that are equipped with OFDM or QAM demodulators. 
       FIG. 3  illustrates an embodiment of a GPON based HOT PON  300 . The GPON HOT PON  300  may comprise a GPON OLT  310 , a HOT PON converter  320 , and a plurality of HOT PON NTs  330 . The GPON OLT  310  may be coupled to the HOT PON converter  320  via a single point-to-point fiber  315 . The HOT PON converter  320  may be coupled to the HOT PON NTs  330  via a coaxial cable  325 . The components of the GPON HOT PON  300  may be configured similar to the corresponding components of the HOT PON  120 . The GPON HOT PON  200  may support up to about 128 HOT PON NTs  330 . 
     The GPON OLT  310  may be a TDM PON OLT that transmits data using the GPON protocol. The GPON may have a substantially larger bandwidth than the EPON. For example, the GPON data may be transmitted at about 2.5 Gbps downstream and 1.25 Gbps upstream. The GPON HOT PON converter  320  may be similar to the EPON HOT PON converter  220 . However, the GPON HOT PON converter  320  may handle GPON GEM frames instead of EPON Ethernet frames. The GPON OLT  310  may be located at a central office and the HOT PON converter  320  may be located in the field away from the GPON OLT  310 . The fiber  315  between the GPON OLT  310  and the HOT PON converter  320  may not comprise any splitters and hence may reach to about 70 km or more. The GPON NTs  330  may be similar to the EPON NTs  230 , but may handle GPON frames instead of EPON frames. 
       FIG. 4  illustrates an embodiment of a combined EPON and GPON based HOT PON  400 . The combined EPON and GPON HOT PON  400  may comprise both an EPON HOT PON and a GPON HOT PON that may be similar to the HOT PONs above. The EPON HOT PON and GPON HOT PON may share the same coaxial cable but on the different frequency bands. The combined EPON and GPON HOT PON  400  may comprise an EPON OLT  410 , a GPON OLT  412 , a HOT PON converter  420 , a plurality of EPON HOT PON NTs  430 , and a plurality of GPON HOT PON NTs  432 . Each of the EPON OLT  410  and GPON OLT  412  may be coupled to the HOT PON converter  420  via a corresponding single fiber  415  and  416 , respectively. The HOT PON converter  420  may be coupled to a plurality of EPON HOT PON NTs  430  and GPON HOT PON NTs  432  via a plurality of coaxial cables  425 . The EPON HOT PON NTs  430  and GPON HOT PON NTs  432  may share the same coaxial cables  425 . The components of the combined EPON and GPON HOT PON  400  may be configured similar to the corresponding components of the HOT PON  120 . The combined EPON and GPON HOT PON  400  may support up to about 32,768 logical EPON HOT PON NTs  430  and up to about 128 GPON HOT PON NTs  432 . In other embodiments, the combined EPON and GPON HOT PON  400  may comprise more EPON OLTs  410  and/or GPON OLTs  412  that may share the HOT PON converter  420  via a plurality of corresponding optical fibers. 
     In case of migration from HOT PON to FTTH, the HOT PON converter  420  may be replaced by a splitter  422  for the fiber  415  corresponding to the EPON OLT  410  and a splitter  424  for the fiber  416  corresponding to the GPON OLT  412 . The splitter  422  may couple the EPON OLT  410  to all the corresponding EPON NTs  430  and the splitter  424  may couple the GPON OLT  412  to all the corresponding GPON NTs  432 , e.g., via optical fiber cables. The installed GPON HOT PON NTs and EPON HOT PON NTs may be change to corresponding GPON NTs and EPON NTs by replacing the plug in GPON HOT PON electrical transceivers and EPON HOT PON electrical transceivers with corresponding plug small form-factor pluggable (SFP) GPON transceivers and SFP EPON transceivers, respectively. 
     The TDM signals may comprise a plurality of different time slots assigned to the different NTs. Each time slot may comprise Ethernet data for a corresponding EPON NT  430  (in the case of the EPON OLT  410 ) or Gigabit Passive Optical Network Encapsulation Method (GEM) data for a corresponding GPON NT  432  (in the case of the GPON OLT  412 ). The HOT PON converter  420  may then redistribute the Ethernet and/or GEM frames over a plurality of different frequency channels to the corresponding NTs using OFDM or bounded QAMs. The TDM to OFDM converter  420  may then reuse TDM PONs scheduling protocols in the point-to-multipoint coaxial cable sections instead of designing another scheduling protocol for coaxial cable. The transmitted data may still comprise TDM PON MAC frames that may be processed by the corresponding NTs in a manner similar to a TDM PON, i.e., using the TDM protocol. Additionally, the HOT PON converter  420  may forward video broadcast from the OLTs to the NTs over a dedicated or predetermined frequency channel, e.g., in parallel with the Ethernet and GEM frames. 
       FIG. 5  illustrates an embodiment of a HOT PON converter  500  that may be used in the EPON HOT PON  200 , GPON HOT PON  300 , or combined EPON and GPON HOT PON  400 . As such, the HOT PON converter  500  may be coupled to at least one TDM PON OLT  501 , via an optical fiber, and to a plurality of HOT PON (HP) NTs  530 , via a coaxial cable. The TDM PON OLT  501  may be an EPON OLT and/or a GPON OLT and the HP NTs  530  may be EPON HP NTs and/or GPON HP NTs, as described above. 
     The HOT PON converter  500  may comprise an downstream optical receiver (RX) and clock and data recovery (CDR) module  502 , a PON MAC frame processor  504 , a QAM/OFDM coding module and framer  506 , and a RF up-conversion module  508 , which may be used to convert downstream signals from the TDM PON OLT  501  to the HP NTs  530 . The HOT PON converter  500  may also comprise an upstream burst mode receiver and CDR module  510 , a QAM/OFDM decoding module  512 , a second PON MAC frame processor  514 , and an upstream optical transmitter (TX)  516 , which may be used to convert upstream signals from the HP NTs  530  to the TDM PON OLT  501 . The downstream and upstream signals may be combined/separated by an optical splitter  522  at the optical fiber coupled to the TDM PON OLT  501 . The downstream and upstream signals may also be combined/separated by an electrical splitter  532  at the coaxial cable coupled to the HP NTs  530 . The components of the HOT PON converter  500  may be implemented using hardware, and in some embodiment also using software. 
     The downstream optical signals from the TDM PON OLT  501  may be received by the optical RX and CDR module  502  that extract clock information. The extracted TDM data in the signals may then be processed by the PON MAC frame processor  504  in Ethernet (for EPON) or GEM (for GPON) frames. The frames may then be forwarded to the QAM/OFDM coding module and framer  506  to implement the QAM and/or OFDM schemes. The data may then be transmitted by the RF up-conversion module  508  in frequency domain and electrical RF signal formats. The upstream electrical signals from the HP NTs  530  may be received by the burst RX and CDR module  510  that implements CDR. The QAM and OFDM data in the signals may then be processed by the QAM/OFDM decoding module  512  based on the QAM and OFDM schemes. The demodulated data may then be processed to obtain the TDM PON MAC frames by the second PON MAC frame processor  514 . The TDM data may then be transmitted as optical signals by the upstream optical TX  516  to the TDM PON OLT  510 . The upstream optical TX  516  in HOT PON converter  500  may operate in continuous mode instead of burst mode due to the HOT PON architecture. 
     Unlike some other systems, where an OLT may be coupled to a plurality of ONUs via a shared optical fiber, only one optical link may be extended between the HOT PON TDM to HOT PON converter  500  and the TDM PON OLT  501  via a corresponding fiber. Thus, the HOT PON converter  500  may not need to operate in a burst mode to send upstream signals, e.g., intermittently, to the TDM PON OLT  501 . Instead, the HOT PON converter  500  may be configured to operate at an “ON” state using a continuous transmission mode for upstream signals, which may improve upstream signal quality and reduce errors. 
     Additionally, the EPON HOT PON  200 , GPON HOT PON  300 , or combined EPON and GPON HOT PON  400  systems may have only collision domain, i.e., collision in the point-to-multipoint coaxial cable sections. Collisions are not possible in fiber section in HOT PON architecture. Other architectures may have two collision domains, where collisions may occur in the point-to-multipoint optical fiber network and the point-to-multipoint coaxial cable network. 
       FIG. 6  illustrates an embodiment of an EPON HOT PON frame  700  that may be received by a HOT PON converter from an EPON OLT after CDR and removing EPON line code and then encapsulated using the OFDM scheme or bounded QAM channels and sent in the downstream direction. The EPON frame  700  may also be encapsulated by the HOT PON converter and sent to the OLT in the upstream direction. Specifically, the EPON frame  700  may comprise Ethernet data. As such, the EPON frame  700  may comprise an EPON header  710  and an Ethernet frame  720 . The EPON header  710  may comprise an Inter-Frame Gap (IFG)  711 , an unused field  712  (e.g., comprising about 2 bits), a Start of Logical Link Identifier (LLID) Delimiter (SLD)  713  (e.g., comprising about 1 bit), a second unused field  714  (e.g., comprising about 2 bits), a LLID  715  (e.g., comprising about 2 bits), and a Cyclic Redundancy Check (CRC)  716  (e.g., comprising about 2 bits). The EPON header  710  may also comprise a destination address (DA)  721  (e.g., comprising about 6 bits), a source address (SA)  722  (e.g., comprising about 6 bits), a link trace (LT)  723  (e.g., comprising about 2 bits) a payload  724  (e.g., that may comprise any size from about 46 bits to about 1,500 bits), and a Frame Check Sequence (FCS)  725  (e.g., comprising about 4 bits). The Ethernet frame  720  may comprise Ethernet data that may be assigned to a plurality of NTs using the TDM scheme. For instance, the Ethernet frame  720  may comprise a plurality of subsequent fields or slots, which may correspond to the different NTs. The fields in the EPON header  710  may be typical EPON fields and the fields of the Ethernet frame may be configured based on the EPON TDM protocol. 
       FIG. 7  illustrates an embodiment of multiple HOT PON communication channels  800  that may be supported in the EPON HOT PON  200 , GPON HOT PON  300 , or combined EPON and GPON HOT PON  400 . The HOT PON communication channel  800  may comprise one or more OFDM upstream (US) channels  810  or bounded QAM channels, a video (e.g., QAM video) channel  820 , and one or more OFDM downstream (DS) channels  830  or bounded QAM channels. The OFDM or bounded QAM US channels  810  may range from about 5 to about 300 Megahertz (MHz) and may be received by the HOT PON converter from a plurality of NTs. The OFDM or bounded QAM DS channels  830  may range from about 700 to about 1,000 MHz and may be transmitted by the HOT PON converter to the NTs. The video channels  820  may range from about 300 to about 700 MHz and may also be transmitted by the HOT PON converter to the NTs. Band gaps may be maintained between the three channels to avoid cross talk or interference. In some embodiments, the HOT PON converter or the coaxial cable may comprise one or more filters to properly transmit/receive the different channels. 
     The coaxial cable echo delay is in the order of few microseconds (μs). If OFDM schedule is used, then the OFDM symbol length is required to be sufficiently long so that a cyclic prefix (CP) is longer than echo delay in the cable. The OFDM sub-channel number in the above frequency band may be few thousands, for example about 2,000 OFDM sub-channels. The resulting OFDM frame may be relatively long, e.g., in the order of few hundred μs, which may not be efficient to transmit relatively short EPON frames, e.g., of about 64 bytes minimum in EPON case. If bounded QAM channels are used in HOT PON architecture, substantially shorter frames may be used that may be more efficient to transmit short EPON frames. In the above frequency band, about 20, 128, or 256 channels may be bounded to provide about 1 Gbps bandwidth. 
       FIG. 8  illustrates an embodiment of a HOT PON data forwarding method  900 , which may be used in a HOT PON PON, such as the EPON HOT PON  200 , GPON HOT PON  300 , and combined EPON and GPON HOT PON  400 . The HOT PON data forwarding method  900  may extend the TDM PON protocols (e.g., for an EPON, GPON, or other PON types) to the coaxial cable plant using the OFDM scheme or bounded QAM channels and may be implemented at a HOT PON converter. The HOT PON data forwarding method  900  may be used to process and forward downstream data from the OLT to the NTs. 
     The method  900  may begin at block  910 , where a TDM optical signal may be received from an OLT (e.g., an EPON or GPON OLT). This may be achieved using the optical RX CDR module  502 . At block  920 , the TDM optical signal may be processed to extract TDM PON frames (e.g., EPON or GPON TDM) in Ethernet or GEM frames. This may be achieved using the PON MAC frame processor  504 . At block  930 , the encapsulated TDM frames may be processed, modulated, and encapsulated using the OFDM scheme or bounded QAM. This may be achieved using the QAM/OFDM coding module and framer  506  or the QAM/OFDM coding module  602 . At block  940 , the OFDM or bounded QAM encapsulated TDM PON frames may be transmitted as electrical signals via a coaxial cable to a plurality of NTs. This may be achieved using the RF up-conversion module  508  or  606 . The method  900  may then end. A similar forwarding method may also be implemented by the HOT PON converter to process and forward upstream data from the NTs to the OLT, e.g., using the upstream signal processing components of the HOT PON converter  500 . The upstream data forwarding method may comprise the reverse steps of the HOT PON data forwarding method  900 . 
       FIG. 9  illustrates an embodiment of a network unit  1000 , which may be any device that transports and processes data through the HOT PON. For instance, the network unit  1000  may be located in any of the network components described above, e.g., at any one of the HOT PON converter, OLT, and NTs. The network unit  1000  may comprise one or more ingress ports or units  1010  coupled to a receiver (Rx)  1012  for receiving signals and frames/data from other network components. The network unit  1000  may comprise a logic unit  1020  to determine which network components to send the packets to. The logic unit  1020  may be implemented using hardware, software, or both. The network unit  1000  may also comprise one or more egress ports or units  1030  coupled to a transmitter (Tx)  1032  for transmitting signals and frames/data to the other network components. The receiver  1012 , logic unit  1020 , and transmitter  1032  may also implement or support the dynamic configuration and forwarding method  900 , and the service reachability forwarding scheme  900  and/or  1000 . The components of the network unit  1000  may be arranged as shown in  FIG. 9 . 
     The network components described above may be implemented on any general-purpose network component, such as a computer or network component with sufficient processing power, memory resources, and network throughput capability to handle the necessary workload placed upon it.  FIG. 10  illustrates a typical, general-purpose network component  1100  suitable for implementing one or more embodiments of the components disclosed herein. The network component  1100  includes a processor  1102  (which may be referred to as a central processor unit or CPU) that is in communication with memory devices including secondary storage  1104 , read only memory (ROM)  1106 , random access memory (RAM)  1108 , input/output (I/O) devices  1110 , and network connectivity devices  1112 . The processor  1102  may be implemented as one or more CPU chips, or may be part of one or more application specific integrated circuits (ASICs). 
     The secondary storage  1104  is typically comprised of one or more disk drives or tape drives and is used for non-volatile storage of data and as an over-flow data storage device if RAM  1108  is not large enough to hold all working data. Secondary storage  1104  may be used to store programs that are loaded into RAM  1108  when such programs are selected for execution. The ROM  1106  is used to store instructions and perhaps data that are read during program execution. ROM  1106  is a non-volatile memory device that typically has a small memory capacity relative to the larger memory capacity of secondary storage  1104 . The RAM  1108  is used to store volatile data and perhaps to store instructions. Access to both ROM  1106  and RAM  1108  is typically faster than to secondary storage  1104 . 
     At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R l , and an upper limit, R u , is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R l +k*(R u −R l ), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 7 percent, . . . , 70 percent, 71 percent, 72 percent, . . . , 97 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present disclosure. The discussion of a reference in the disclosure is not an admission that it is prior art, especially any reference that has a publication date after the priority date of this application. The disclosure of all patents, patent applications, and publications cited in the disclosure are hereby incorporated by reference, to the extent that they provide exemplary, procedural, or other details supplementary to the disclosure. 
     While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented. 
     In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.

Technology Classification (CPC): 7