Abstract:
An apparatus including a data framer and an optical transmitter. The data framer is used to frame a data stream into a plurality of frames, each of the frames includes a plurality of fields sized to align the frames with a word boundary greater than or equal to four bytes long. The optical transmitter is coupled to the data framer and is used to transmit the frames. Included is an apparatus with at least one component for implementing a method for encapsulating a data stream with at least one Gigabit Passive Optical Network (GPON) Encapsulation Method (GEM) payload aligned with a word boundary of at least four bytes long, encapsulating the GEM payload with a GPON Transmission Convergence (GTC) frame aligned with the word boundary, and transmitting the GTC frame.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a continuation of U.S. patent application Ser. No. 12/355,837, filed on Jan. 19, 2009, and entitled “Gigabit Passive Optical Network Transmission Convergence Extension for Next Generation Access”, which claims priority to U.S. Provisional Patent Application No. 61/046,474, filed Apr. 21, 2008, and entitled “Gigabit Passive Optical Network Transmission Convergence Extension for Next Generation Access”, both of which are hereby incorporated by reference in their entireties. 
     
    
     BACKGROUND 
       [0002]    A passive optical network (PON) is one system for providing network access over “the last mile.” The PON is a point to multi-point network comprised of an optical line terminal (OLT) at the central office, an optical distribution network (ODN), and a plurality of optical network units (ONUs) at the customer premises. In some PON systems, such as Gigabit PON (GPON) systems, downstream data is broadcasted at about 2.5 Gigabits per second (Gbps) while upstream data is transmitted at about 1.25 Gbps. However, the bandwidth capability of the PON systems is expected to increase as the demands for services increase. To meet the increased demand in services, the logic devices in emerging PON systems, such as Next Generation Access (NGA), are being reconfigured to transport the data frames at higher bandwidths, for example at about ten Gbps, and to support a larger number of ONUs. 
       SUMMARY 
       [0003]    In one embodiment, the disclosure includes an apparatus comprising a data framer configured to frame a data stream into a plurality of frames each comprising a plurality of fields sized to align the frames with a word boundary greater than or equal to about four bytes long, and an optical transmitter coupled to the data framer and configured to transmit the frames. 
         [0004]    In another embodiment, the disclosure includes an apparatus comprising at least one component configured to implement a method comprising encapsulating a data stream with at least one GPON Encapsulation Method (GEM) payload aligned with a word boundary at least about four bytes long, encapsulating the GEM payload with a GPON Transmission Convergence (GTC) frame aligned with the word boundary, and transmitting the GTC frame. 
         [0005]    In yet another embodiment, the disclosure includes a method comprising encapsulating a data stream into a plurality of fields, aligning the lengths of the fields individually or combined to a word boundary equal to at least about four bytes, packaging the fields into a frame, and transmitting the frame. 
         [0006]    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 
         [0007]    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. 
           [0008]      FIG. 1  is a schematic diagram of an embodiment of a PON. 
           [0009]      FIG. 2  is an illustration of an embodiment of a downstream GPON Transmission Convergence frame. 
           [0010]      FIG. 3  is an illustration of an embodiment of an upstream GPON Transmission Convergence frame. 
           [0011]      FIG. 4  is an illustration of an embodiment of a GPON Encapsulation Method payload. 
           [0012]      FIG. 5  is a flowchart of an embodiment of a framing method. 
           [0013]      FIG. 6  is a schematic diagram of an embodiment of a general-purpose computer system. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    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. 
         [0015]    Reconfiguring the PON system&#39;s logic to support higher transmission rates or more ONUs may include modifying existing protocols, such as a GPON protocol as defined by the ITU-T G.984.3 standard, which is incorporated herein by reference. The GPON protocol comprises a GTC layer that defines the frames for encapsulating the data, such as Ethernet frames or other packets. Disclosed herein is a system and method for extending the GTC layer of the GPON protocol for NGA. The extended GTC layer may define a plurality of frames similar to the GTC layer of the GPON protocol, where at least some of the frames may be modified to support higher bandwidth for NGA. Additionally, the modified frames may be used for transporting a larger number of data flows for a larger quantity of ONUs. The modified frames may comprise downstream GTC frames and upstream GTC frames, which may comprise network control and management information and GEM payloads. 
         [0016]    To support the increase in transmission rates, the length of the fields of the modified frames may be aligned with a similarly scaled word boundary. For instance, if the transmission rates are increased about four times, e.g., to about ten Gbps, the length of the fields of the modified frames may be aligned with about four times the word boundary, e.g., to about four bytes. Alternatively, the word boundary may be any integer multiple of about four bytes long. Accordingly, the GEM payloads and other network control and management information may be encapsulated into frames comprising field lengths equal to integer multiples of about four bytes. As such, the data may be encapsulated and de-capsulated using available electronic circuits with about the same performance or processing speed and without substantial upgrades or increase in complexity. The increase in the length of the fields may also provide more addresses or identifiers to support more ONUs and more data flows. Additionally, at least some of the fields may be updated to deprecate or disable Asynchronous Transfer Mode (ATM) functionality, which may not be used for NGA. 
         [0017]      FIG. 1  illustrates one embodiment of a PON  100 . The PON  100  comprises an OLT  110 , a plurality of ONUs  120 , and an ODN  130 , which may be coupled to the OLT  110  and the ONUs  120 . The PON  100  may be a communications network that does not require any active components to distribute data between the OLT  110  and the ONUs  120 . Instead, the PON  100  may use the passive optical components in the ODN  130  to distribute data between the OLT  110  and the ONUs  120 . The PON  100  may be NGA systems, such as ten Gbps GPONs (or XGPONs), which may have a downstream bandwidth of about ten Gbps and an upstream bandwidth of at least about 2.5 Gbps. Other examples of suitable PONs  100  include the asynchronous transfer mode PON (APON) and the broadband PON (BPON) defined by the ITU-T G.983 standard, the GPON defined by the ITU-T G984 standard, the Ethernet PON (EPON) defined by the IEEE 802.3ah standard, and the wavelength division multiplexed (WDM) PON (WPON), all of which are incorporated herein by reference as if reproduced in their entirety. 
         [0018]    In an embodiment, the OLT  110  may be any device that is configured to communicate with the ONUs  120  and another network (not shown). Specifically, the OLT  110  may act as an intermediary between the other network and the ONUs  120 . For instance, the OLT  110  may forward data received from the network to the ONUs  120 , and forward data received from the ONUs  120  onto the other network. Although the specific configuration of the OLT  110  may vary depending on the type of PON  100 , in an embodiment, the OLT  110  may comprise a transmitter and a receiver. When the other network is using a network protocol, such as Ethernet or Synchronous Optical Networking/Synchronous Digital Hierarchy (SONET/SDH), that is different from the PON protocol used in the PON  100 , the OLT  110  may comprise a converter that converts the network protocol into the PON protocol. The OLT  110  converter may also convert the PON protocol into the network protocol. The OLT  110  may be typically located at a central location, such as a central office, but may be located at other locations as well. 
         [0019]    In an embodiment, the ONUs  120  may be any devices that are configured to communicate with the OLT  110  and a customer or user (not shown). Specifically, the ONUs  120  may act as an intermediary between the OLT  110  and the customer. For instance, the ONUs  120  may forward data received from the OLT  110  to the customer, and forward data received from the customer onto the OLT  110 . Although the specific configuration of the ONUs  120  may vary depending on the type of PON  100 , in an embodiment, the ONUs  120  may comprise an optical transmitter configured to send optical signals to the OLT  110  and an optical receiver configured to receive optical signals from the OLT  110 . Additionally, the ONUs  120  may comprise a converter that converts the optical signal into electrical signals for the customer, such as signals in the Ethernet or ATM protocol, and a second transmitter and/or receiver that may send and/or receive the electrical signals to a customer device. In some embodiments, ONUs  120  and optical network terminals (ONTs) are similar, and thus the terms are used interchangeably herein. The ONUs may be typically located at distributed locations, such as the customer premises, but may be located at other locations as well. 
         [0020]    In an embodiment, the ODN  130  may be a data distribution system, which may comprise optical fiber cables, couplers, splitters, distributors, and/or other equipment. In an embodiment, the optical fiber cables, couplers, splitters, distributors, and/or other equipment may be passive optical components. Specifically, the optical fiber cables, couplers, splitters, distributors, and/or other equipment may be components that do not require any power to distribute data signals between the OLT  110  and the ONUs  120 . Alternatively, the ODN  130  may comprise one or a plurality of processing equipment, such as optical amplifiers. The ODN  130  may typically extend from the OLT  110  to the ONUs  120  in a branching configuration as shown in  FIG. 1 , but may be alternatively configured in any other point-to-multi-point configuration. 
         [0021]    In an embodiment, the OLT  110  and the ONUs  120  may comprise a data framer, which may be coupled to the transmitter and/or the receiver. Specifically, the data framer may be any device configured to process the data between the OLT  110  and the ONUs  120  by encapsulating the data, such as Ethernet data, into frames or decapsulating the data from the frames according to a PON protocol. For instance, the data framer may be hardware, such as a processor, comprising electronic or logic circuitry, which may be designed for such purpose. Alternatively, the data framer may be software or a firmware, which may be programmed for such purpose. The PON protocol may be used by the OLT  110  and the ONUs  120  to exchange the data, such as a GPON protocol defined by the ITU-T G.984.3 standard. The GPON protocol may comprise a GTC layer that provides a plurality of functionalities, including media access control (MAC) functionalities for data framing over upstream and downstream channels, a GEM for framing the data, and status reporting signaling using dynamic bandwidth allocation for upstream data. 
         [0022]    In an embodiment, the GTC layer may define a word boundary, which may represent a fixed logic block that aligns the data in the frames. The data framer may align the length of the data fields of the frames to the word boundary to avoid variable or odd length fields in the frames and hence variable or odd length logic blocks. Variable or odd length logic blocks may be undesirable because they may be more difficult to process using the data framer at the OLT  110  or the ONUs  120 . The word boundary may be chosen based on the transmission rates of the system, such that the aligned data can be processed using available electronic circuits with tolerable processing speeds or clock speeds. For example, in GPON systems, the word boundary may be set to about one byte (about eight bits), and hence the length of the fields may be equal to integer multiples of about one byte. 
         [0023]    To accommodate the higher data rates for NGA, the GTC layer of the GPON protocol may be extended by increasing the word boundary based on the increased bandwidth. Specifically, as the data rates increase, the available electronic circuits or logic circuitry may require higher clock speeds for processing and framing the data, which may not be practical. However, when the word boundary is increased, more data per logic block may be handled by such circuits, which may reduce the clock speed requirement. Accordingly, the word boundary may be scaled proportionally to the increase in bandwidth to maintain about the same processing speed requirement, which may be achieved by the available electronic circuits. For instance, to accommodate the higher data rates for NGA at about ten Gbps, which may be equal to about four times the 2.5 Gbps rate, the word boundary of about one byte may be scaled proportionally by about four times. As such, the increased word boundary in the extended GTC layer may be equal to about four bytes or about 32 bits. In other embodiments, the increased word boundary may be greater than about four bytes, for example about eight bytes. Further, the frame may be aligned with the increased word boundary by increasing the length of the fields in the frames. The increased field lengths may also be used to accommodate more values, addresses, or identifiers to support more ONUs  120 , more data flows, or both. 
         [0024]      FIG. 2  illustrates an embodiment of a downstream GTC frame  200 . The downstream GTC frame  200  may comprise downstream data transmitted from the OLT  110  to any of the ONUs  120 , for instance over a downstream channel. For instance, the downstream GTC frame  200  may broadcasted by the OLT  110  and comprise payload data as well as network control and management information. Each ONU  120  may receive the downstream GTC frame  200  and identify the corresponding data assigned to the ONU  120  using some addressing information, such as an ONU identifier (ONU-ID). The downstream GTC frame  200  may comprise a Physical Control Block downstream (PCBd)  210  and a Downstream Payload  220 , which may be a GEM payload as described below. The PCBd  210  may comprise a plurality of fields, such as a Physical Synchronization (PSync)  211 , an Identification (Ident)  212 , a Physical Layer Operations, Administration and Maintenance (PLOAM) downstream or PLOAMd  213 , a Bit Interleaved Parity (BIP)  214 , a Payload Length downstream (Plend)  215 , and an Upstream Bandwidth map (US BWmap)  216 . 
         [0025]    The PSync  211  may comprise a fixed pattern that precedes the remaining fields in the PCBd  210 . This pattern may be used at the ONUs  120 , for instance at the data framer coupled to the receiver, to detect the beginning of the downstream GTC frame  200  and establish synchronization. For example, the PSync  211  may comprise the fixed pattern 0xB6AB31E0, which may not be scrambled. In the GTC layer of the GPON protocol, the length of the PSync  211  may be equal to about four bytes, which may already be aligned and equal to about the increased word boundary to support a higher bandwidth in the GPON or NGA, e.g., about ten Gbps transmission rates. Hence, no changes may be required for the PSync  211  in the extended GTC layer. 
         [0026]    The Ident  212  may comprise a counter to provide lower rate synchronous reference signals, which may be used by the ONU  120  with the PSync  211  for synchronization purposes. For instance, similar to the PSync  211 , the length of the Ident  212  in the GPON protocol may be equal to about 32 bits, of which the first bit may be a forward error correction (FEC) bit, the second bit may be reserved, and the remaining and less significant about 30 bits may comprise a counter that may be incremented for each next transmitted Ident  212 . When the counter reaches a predetermined maximum value, the Ident  212  may be reset to zero on the next downstream GTC frame  200 . Similar to the PSync  211 , since the length of the Ident  212  may be aligned and equal to about the increased word boundary, the Ident  212  may not be changed in the extended GTC layer. 
         [0027]    The PLOAMd  213  may comprise a PLOAM message, which may be sent from the OLT  110  to the ONUs  120  and include Operations, Administration and Maintenance (OAM) related alarms or threshold-crossing alerts triggered by system events. The PLOAMd  213  may comprise a plurality of sub-fields, such as an ONU-ID, a message identifier (Message-ID), a message data, and a Cyclic Redundancy Check (CRC). The ONU-ID may comprise an address, which may be assigned to one of the ONUs  120  and may be used by that ONU  120  to detect its intended message. The Message-ID may indicate the type of the PLOAM message and the message data may comprise the payload of the PLOAM message. The CRC may be used to verify the presence of errors in the received PLOAM message. For instance, the PLOAM message may be discarded when the CRC fails. To support the higher bandwidth in the GPON or NGA, the length of the PLOAMd  213  may be changed to an integer multiple of about four bytes long, for example about 16 bytes long, thereby aligning the data at about four bytes. Further, the length of the ONU-ID may be equal to about one byte, and hence may be used to indentify up to about 256 individual ONUs  120 . In the extended GTC layer, the length of the ONU-ID may be increased to about four bytes to align the data to the increased word boundary. Accordingly, the extended ONU-ID may be used to identify substantially more than 256 ONUs  120 . Further, the format of the CRC, such as a CRC-8 format with generator polynomial (x 8 +x 2 +x+1), may be changed to account for at least some of the additional bits of the extended PLOAM message. Alternatively, the same CRC format may be used, and hence the first bit in the PLOAMd  213 , which may not be covered by the CRC format, may not be protected or considered for error detection. 
         [0028]    The BIP  214  may comprise a bit interleaved parity of all the bytes transmitted since the last receive BIP  214 . The bit interleaved parity may also be calculated at the ONUs  120  and then compared to the bit interleaved parity of the BIP  214  to measure the number of errors on the link. The BIP  214  may be equal to about four bytes, which aligns it with the increased word boundary in the extended GTC layer. 
         [0029]    The Plend  215  may comprise a plurality of subfields, including a B length (Blen) and a CRC. The Blen may indicate the length of the US BWmap  216 , where the actual length of the US BWmap  216  in bytes may be equal to about eight times the value of Blen. The CRC may be configured substantially similar to the CRC of the PLOAMd  213 . In some systems that support ATM communications, the subfields may also include an A length (Alen) subfield that indicates the length of an ATM payload, which may comprise a portion of the downstream GTC frame  200 . To disable or deprecate ATM communications or functionality in the GPON or NGA, the Alen may be removed or discarded in the extended GTC layer. To compensate for the missing bits of the Alen and align the length of the Plend  215  to the increased word boundary, the length of the Blen, the CRC, or both may be adjusted to obtain a total length of about four bytes for the Plend  215 . For instance, the length of the CRC may be increased, which also improves error detection. 
         [0030]    The US BWmap  216  may comprise an array of blocks or subfields, each of which may have a length of about eight bytes. Each block may comprise a single bandwidth allocation to an individual Transmission Container (T-CONT), which may be used for managing upstream bandwidth allocation in the GTC layer. Specifically, the T-CONT may be a transport entity in the GTC layer that may be configured to transfer higher-layer information from an input to an output, e.g., from the OLT  110  to any of the ONUs  120 . Each block may comprise a plurality of subfields, such as an Allocation identifier (Alloc-ID), a Flags, a Start Time (SStart), a Stop Time (SStop), and a CRC. Since the length of the US BWmap  216  may be equal to an integer multiple of about eight bytes, the total length of the US BWmap  216  may already be aligned with the increased word boundary, and hence may not be changed. However, the granularity of the US BWmap  216  may be changed, for instance to about four bytes in each block. 
         [0031]      FIG. 3  illustrates an embodiment of an upstream GTC frame  300 . The upstream GTC frame  300  may comprise upstream data transmitted from one of the ONUs  120  to the OLT  110 , including payload data and network control and management information, for instance over an upstream channel. The upstream GTC frame  300  may comprise a Physical Layer Overhead upstream (PLOu)  310 , a PLOAM upstream (PLOAMu)  316 , a Dynamic Bandwidth Report upstream (DBRu)  318 , and an Upstream Payload  320 , which may be a GEM payload as described below. The PLOu  310  may comprise a plurality of fields, such as a Preamble  311 , a Delimiter  312 , a BIP  313 , an ONU-ID  314 , and an Indication (Ind)  315 . The upstream GTC frame  300  may also comprise a Guard Time  305 , which may precede the remaining fields and delineate the upstream GTC frame  300 . 
         [0032]    The combined fields of the PLOu  310  may indicate which ONU  120  may have sent the upstream GTC frame  300  to the OLT  110 . For instance, the Preamble  311  and Delimiter  312  may correspond to that ONU  120  and may be formed as indicated by the OLT  110 . The BIP  313  may comprise the bit interleaved parity, as described above, and the ONU-ID  314  may comprise the assigned address corresponding to the ONU  120 . The Ind  315  may indicate the status of the ONU  120  to the OLT  110 , where the upstream GTC frame  300  may be transmitted in substantially real time. In some instances, the BIP  313 , the ONU-ID  314 , and the Ind  315  may not be aligned with the increased word boundary in the extended GTC layer. Hence, the length of the ONU-ID  314  may be about two bytes, and the BIP  313  and the Ind  315  may be about one byte, thereby obtaining a total length of about four bytes for the three fields, which may be suitable, for instance, for about ten Gbps transmission rates. Increasing the length of the ONU-ID  314  may also provide more addresses that may be assigned to more ONUs  120 , e.g., up to about 65,536 ONUs. In some embodiments, the lengths of the Preamble  311  and the Delimiter  312  may also be aligned individually or with the three remaining fields of the PLOu  310  to the increased word boundary. 
         [0033]    Similar to the PLOAMd  213  of the downstream GTC frame  200 , the PLOAMu  316  may comprise a PLOAM message, which may be sent from the ONU  120  to the OLT  110 . The length of the PLOAMu  316  may be an integer multiple of about four bytes long, for example about 16 bytes long, in the extended GTC layer. For instance, the length of the ONU-ID subfield of the PLOAMu  316  may be increased to about two bytes. Further, the format of the CRC subfield, e.g., CRC-8 format with generator polynomial (x 8 +x 2 +x+1), may not be changed where the first bit in the PLOAMu  316  is not covered. 
         [0034]    The DBRu  318  may comprise information that is related to the T-CONT. The DBRu  318  may comprise two subfields, which may be a Dynamic Bandwidth Assignment (DBA) and a CRC. The DBA may indicate a buffer occupancy report, e.g., may comprise the traffic status of the T-CONT. In the extended GTC layer, the length of the DBRu may be matched to the granularity of the US BWmap  216  of the downstream GTC frame  200 , e.g., at about four bytes. As such, the code points of Table 8-1 in ITU-T G.984.3 may be deprecated, replaced, or modified. 
         [0035]      FIG. 4  illustrates an embodiment of a GEM payload  400 . The GEM payload  400  may comprise downstream data from the OLT  110  to the ONUs  120  or upstream data from an ONU  120  to the OLT  110 . For instance, the GEM payload  400  may correspond to the Downstream Payload  220  of the downstream GTC frame  200  or the Upstream Payload  320  of the upstream GTC frame  300 . The GEM payload  400  may comprise a Header  410  and a Payload  420 . The Header  410  may comprise a Payload Length Indicator (PLI)  411 , a Port identifier (PortID)  412 , a Payload Type Indicator (PTI)  413 , and a Header Error Control (HEC)  414 . 
         [0036]    The PLI  411  may indicate the length of the Payload  420  in bytes. The PLI  411  may also indicate the beginning of the GEM payload  400 . The length of the PLI  411  may be equal to about 12 bits, which may indicate a Payload  420  having a length up to about 4,095 bytes. The PortID  412  may also have a length equal to about 12 bits, which may provide up to about 4,096 unique traffic identifiers. The traffic identifiers may correspond to a plurality of data flows, which may be multiplexed. The PTI  413  may indicate the content type of the Payload  420 . The length of the PTI  413  may be equal to about three bits. The HEC  414  may provide error detection and correction functions. For instance, the HEC  414  may comprise about 12 bits of Bose and Ray-Chaudhuri (BCH) code, such as a BCH(39, 12, 2) code with a generator polynomial of x 12 + x   10 +x 8 +x 5 +x 4 +x 3 +1, and a single parity bit. 
         [0037]    In the extended GTC layer, the total length of the Header  410  may be aligned with the increased word boundary. Specifically, the Header  410  may be an integer multiple of about four bytes long, for example about eight bytes long. Accordingly, the length of the PLI  411 , the PortID  412 , the PTI  413 , the HEC  414 , or combinations thereof may be increased. The length of the PLI  411  may be increased to indicate an extended GEM payload  400  comprising more bytes and information. The length of the PortID  412  may be increased to provide more traffic identifiers corresponding to more multiplexed data flows. The length of the PTI  413  may be increased to indicate more information about the Payload  420 . The length of the HEC  414  may be increased to extend the BCH code to account for at least some of the additional bits of the extended Header  410 , for instance for about 63 bits of the Header  410  leaving a remaining parity bit unprotected. 
         [0038]    The Payload  420  may comprise the payload data transported between the OLT  110  and the ONUs  120 . The Payload  420  may also be extended and aligned with the increased word boundary. For instance, up to about three padded bytes, e.g. null or zero value bytes, may be added to the Payload  420  to meet the word boundary alignment. If the Payload  420  is already aligned with the increased word boundary, then no padded bytes may be needed. The length of the Payload  420  and the padded bytes may be indicated using the PLI  411 , the PTI  413 , or both. 
         [0039]      FIG. 5  illustrates one embodiment of a framing method  500 , which may be used to encapsulate, transport, and de-capsulate data, such as Ethernet data, in a PON system, such as the PON  100 . The data may be transported from the OLT  110  to the ONUs  120  or from one of the ONUs  120  to the OLT  110 . The data may correspond to a plurality of ONUs  120 , a plurality of data flows, a plurality of T-CONTs, or combinations thereof. The framing method  500  may be implemented at the extended GTC layer of the GPON protocol. 
         [0040]    At block  510 , the framing method  500  may frame the data to obtain an aligned GEM payload, for instance using the data framer coupled to the transmitter at the OLT  110  or the ONU  120 . As such, the data may be encapsulated with other information in the format of a GEM payload, such as the GEM payload  400 . The other information may comprise the length of the data in bytes, the traffic identifiers of the data flows, the type of the data, other information related to the data, or combinations thereof. The GEM payload may then be aligned with the word boundary based on the downstream bandwidth of the system, which may be about ten Gbps. For instance, the data may be framed in an aligned payload portion of the GEM payload, such as the Payload  420 , and the remaining information may be framed in an aligned header portion of the GEM payload, such as the Header  410 . 
         [0041]    At block  520 , the framing method  500  may frame the aligned GEM payload to obtain an aligned GTC frame. Accordingly, the aligned GEM payload may be encapsulated with other information in the format of a GTC frame, such as the downstream GTC frame  200  or the upstream GTC frame  300 . The other information may comprise a PLOAM message, the ONU-ID, bandwidth allocation for a T-CONT, other information related to the T-CONT, or combinations thereof. The GTC frame may then be aligned with the word boundary, which may be equal to about four bytes. For instance, the aligned GEM payload may be framed in a payload portion of the GTC frame, such as the Downstream Payload  220  or the Upstream Payload  320 , and the remaining information may be framed in an aligned header portion of the GTC frame, such as the PCBd  210  or the PLOu  310 . 
         [0042]    At block  530 , the framing method  500  may transport the aligned GTC frame between the OLT  110  and the ONU(s)  120  via at least some of the components of the PON system. For instance, the aligned GTC frame may be transported along the ODN  130  in a transparent manner without the knowledge of its data content. At block  540 , the framing method  500  may process the aligned GTC frame to obtain the aligned GEM payload in a reverse manner of block  520 , for instance using the data framer coupled to the receiver at the OLT  110  or the ONU  120 . At block  550 , the framing method  500  may process the aligned GEM payload to obtain the data in a reverse manner of block  510 . 
         [0043]    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. 6  illustrates a typical, general-purpose network component  600  suitable for implementing one or more embodiments of the components disclosed herein. The network component  600  includes a processor  602  (which may be referred to as a central processor unit or CPU) that is in communication with memory devices including secondary storage  604 , read only memory (ROM)  606 , random access memory (RAM)  608 , input/output (I/O) devices  610 , and network connectivity devices  612 . The processor  602  may be implemented as one or more CPU chips, or may be part of one or more application specific integrated circuits (ASICs). 
         [0044]    The secondary storage  604  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  608  is not large enough to hold all working data. Secondary storage  604  may be used to store programs that are loaded into RAM  608  when such programs are selected for execution. The ROM  606  is used to store instructions and perhaps data that are read during program execution. ROM  606  is a non-volatile memory device that typically has a small memory capacity relative to the larger memory capacity of secondary storage  604 . The RAM  608  is used to store volatile data and perhaps to store instructions. Access to both ROM  606  and RAM  608  is typically faster than to secondary storage  604 . 
         [0045]    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, 5 percent, . . . , 50 percent, 51 percent, 52 percent, . . . , 95 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. 
         [0046]    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. 
         [0047]    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.