Patent Publication Number: US-2007104227-A1

Title: Distributed digital subscriber line access multiplexers and methods to operate the same

Description:
FIELD OF THE DISCLOSURE  
      This disclosure relates generally to communications networks and/or systems and, more particularly, to distributed digital subscriber line access multiplexers and methods to operate the same.  
     BACKGROUND  
      Digital subscriber line (DSL) technology is commonly utilized to provide Internet related services to subscribers, such as, for example, homes and/or businesses (also referred to herein as users and/or customers). DSL technology enables customers to utilize telephone lines (e.g., ordinary twisted-pair copper telephone lines used to provide Plain Old Telephone System (POTS) services) to connect the customer to, for example, a high data rate broadband Internet network, broadband service and/or broadband content.  
      Communication companies and/or service providers utilize any of a variety of communication servers and/or devices to generate, encode, transport and/or transmit broadband service content (i.e., downstream signals and/or content such as, for example, audio, video, voice, data, pictures, web pages, etc.) to a plurality of users. These communication servers and/or devices also receive and/or decode service content transmitted by the plurality of users (i.e., upstream signals and/or content). For example, a communication company and/or service provider may utilize a plurality of modems (e.g., a plurality of DSL modems) implemented by a DSL Access Multiplexer (DSLAM). A DSLAM includes many, sometimes hundreds, of individual DSL modems and/or modem modules. In general, a DSL modem receives broadband service content from, for example, a backbone server and forms a digital downstream DSL signal to be transmitted to the customer. Likewise, the DSL modem receives an upstream DSL signal from the customer and provides the data transported in the upstream DSL signal to the backbone server.  
      Since each DSL modem and/or modem module may be physically connected to only one telephone line at a time, each modem and/or modem module in the DSLAM will, when provisioned and/or configured, be dedicated to provide DSL services to a single user. DSLAMs may be deployed in neighborhoods and/or business districts, awaiting demand from customers (e.g., a request for a DSL service). Today, when a customer requests the communications company to provide a DSL service, such as, for example, Internet access, broadband Internet access, Voice over Internet Protocol (VoIP), video on demand (VoD) or an Internet Protocol based Television (IPTV) service, the communications company dispatches a technician to connect a particular modem and/or modem module of a DSLAM to the customer&#39;s telephone line.  
      Similarly, when a customer requests that a service be discontinued, or if the customer desires to switch from a first set of services (e.g., all available services) to a second set of services (e.g., a reduced set of services, a slower speed service, etc.), a technician may be sent to re-wire and/or re-provision the DSLAM, as appropriate. Alternatively or additionally, the DSL modem connected to the customer&#39;s telephone line, the DSLAM and/or backbone servers may be re-configured to reflect the second set of services.  
      Since many customers who request a DSL service expect that the service will be provided promptly, (e.g., frequently the same day), many communications companies have installed DSLAMs at various locations in various geographic areas. This allows the customer to be connected promptly without waiting for DSLAM equipment to be installed. However, this pre-installation of DSLAMs is operationally expensive as the pre-installed and/or deployed DSLAM resources are not effectively and/or efficiently utilized since actual demand may either substantially lag the deployment of the DSLAMs or never mature.  
       FIG. 1  illustrates an example prior art communication system. In the illustrated example of  FIG. 1 , an Operations Center  22 , for example, determines that a service (e.g., Video on Demand (VoD) via DSL) is to be available in a particular neighborhood, and instructs and/or commands, for example, a Central Office  24  to provide the service to the neighborhood. The Central Office  24  may contain several communication servers and/or devices to provide a variety of services to various customers (e.g., plain old telephone service (POTS)). The example Central Office  24  of  FIG. 1  may, for example, provide a DSL service via a Feeder One (F 1 ) cable  25  that connects the Central Office  24  to a particular DSL modem in a DSL access multiplexer (DSLAM) (not shown in  FIG. 1 ) located at a Serving Area Interface (SAI)  26 . In the example of  FIG. 1 , a Distribution Cable (F 2 ) pair  27  connects the DSL modem to a Serving Terminal  28 . Finally, a drop cable pair  32  (i.e., a telephone line) connects the Serving Terminal  28  to a customer  30 . In the example system of  FIG. 1 , DSLAMs may, additionally or alternatively, be located within the Central Office  24  and/or the Serving Terminal  28 . Further, the example system of  FIG. 1  may deploy DSLAMs in different locations to serve different subscribers.  
      When the customer  30  requests a service (e.g., VoD via DSL), or requests that a service be discontinued, a service order is created and a technician  34  is dispatched from, for example, a garage  36  to (re-)provision and/or (re-)configure the DSLAM to connect a DSL modem to, or disconnect a DSL modem from, the customer  30 . For example, the technician  34  may add or remove jumpers within, for example, the SAI  26  to connect a DSL modem to, or disconnect a DSL modem from, the F 2  cable pair  27  and/or the F 1  cable  25 . The technician  34  may also be dispatched to a neighborhood to, for example, provide other adjustments that may be necessitated by a change request from a first set of services to a second set of services, to re-configure the DSLAM, to re-provision the DSLAM, to change F 1  pairs out of an unmanned central office, to test and/or change an F 2  pair, etc.  
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic illustration of an example prior art communication system.  
       FIGS. 2, 3 , and  4  are example manners of implementing a distributed Digital Subscriber Line (DSL) Access Multiplexer (DSLAM) constructed in accordance with the teachings of the invention.  
       FIG. 5  is an example manner of mapping, cross-switching and/or cross-connecting one or more analog modules to one or more signal processing modules.  
       FIG. 6  is another example manner of implementing a distributed DSLAM constructed in accordance the teachings of the invention.  
       FIGS. 7 and 8  are schematic illustrations of example communication systems constructed in accordance with of the teachings of the invention.  
       FIG. 9  is a flowchart representative of example machine readable instructions which may be executed to configure the example DSLAMs and/or systems of  FIGS. 2-8 .  
       FIG. 10  is a schematic illustration of an example processor platform that may be used and/or programmed to execute the example machine readable instructions represented by  FIG. 9  to configure the example DSLAMs and/or systems of  FIGS. 2-8 . 
    
    
     DETAILED DESCRIPTION  
      Methods and apparatus to implement a distributed digital subscriber line (DSL) access multiplexer (DSLAM) are disclosed. An disclosed example distributed DSLAM comprises a first module comprising at least one signal processing device to process a DSL signal and a communication link to transport the DSL signal between the first module and a second module. The second module of the example distributed DSLAM comprises a plurality of analog interfaces connectable to respective ones of a plurality of lines for providing services to respective ones of a plurality of subscribers. The second module also includes a switching interface to route the DSL signal between the communication link and a first one of the plurality of analog interfaces associated with a first one of the plurality of subscribers.  
      A disclosed example module of a distributed DSLAM comprises a signal processing device configurable to process a DSL signal to be routed to an analog interface associated with a subscriber line and a communication device to communicate the DSL signal from the signal processing device to the analog interface. The analog interface is physically separate from the module and is connected to a first end of the subscriber line that is terminated at the other end by a DSL modem Another disclosed example module of a distributed DSLAM comprises an analog interface connectable to a subscriber line for providing a DSL service to a respective subscriber, a communication device to receive a DSL signal from a second module of the distributed DSLAM that is physically separate from the module, and a switching interface to route the DSL signal between the communication device and the analog interface. The analog interface is to transmit the DSL signal on the subscriber line and to connect to a first end of the subscriber line that is terminated at the other end by a DSL modem.  
      In the interest of brevity and clarity, throughout the following disclosure references will be made to connecting a DSL modem and/or a communication service to a customer. It will be readily apparent to persons of ordinary skill in the art that connecting a DSL modem to a customer involves, for example, connecting the DSL modem operated by a communications company to a telephone line (i.e., subscriber line) that is connected to a second DSL modem located in, for example, a home and/or place of business owned by the customer. The second DSL modem may be further connected to another communication and/or computing device (e.g., a personal computer) that the customer operates to access a service (e.g., Internet access) via the first and second DSL modems, the telephone line and the communications company.  
       FIG. 2  illustrates an example manner of implementing a distributed DSLAM constructed in accordance with the teachings of the invention. The example distributed DSLAM of  FIG. 2  is partitioned into a digital module  305  and a plurality of analog interfaces  310  (e.g., analog modules  310 ) to implement respective ones of a plurality of DSL modems. For ease of understanding and clarity, only a single analog interface  310  is illustrated in detail in  FIG. 2 . The other analog interfaces  310  are not shown in detail. However, persons of ordinary skill in the art will readily appreciate that the analog interfaces  310  of  FIG. 2  are typically substantially identical. Similarly, although only three analog interfaces  310  are shown in  FIG. 2 , typically more than three analog interfaces  310  will be present.  
      The example digital module  305  of  FIG. 2  includes a fiber optic link and/or cable  42  and a POTS link  44  (e.g., comprising one or more telephone lines, the F 1  cable  25  of  FIG. 1 , etc.). In the illustrated example of  FIG. 2 , the fiber optic link  42  is used to exchange digital signals with one or more broadband content servers and/or communication devices (not shown in  FIG. 2 ). The fiber optic link  42  of the illustrated example will typically transport data associated with multiple customers to one or more of the plurality of DSL modems. To convert between the optical signals received and/or transmitted via the fiber optic link  42  and electrical signals processed by a switch fabric  48 , the example digital module  305  of  FIG. 2  includes an uplink transceiver  46 . As used herein, the fiber optic signal and/or the electrical signals are regarded as digital signals.  
      To route digital signals bi-directionally between the uplink XCVR  46  and a digital signal processor (DSP)  50 , the example digital module  305  of  FIG. 2  includes a switch fabric  48 . The switch fabric  48  switches, connects and/or routes data associated with a customer via the DSP  50  to a corresponding analog module  310  providing DSL services to that customer.  
      To process data and/or signals received from the switch fabric  48  and associated with a particular customer, and to generate downstream DSL signals suitable for transmitting to that customer, the example digital module  305  of  FIG. 2  includes the DSP  50 . For example, among other things, the DSP  50  of the illustrated example receives a block of bits from a broadband content server (e.g., a backbone server) via the uplink XCVR  46  and the switch fabric  48 , applies forward error correction (FEC) to the block, creates one or more data frames from the encoded block, and modulates the frame suitably for conversion to the analog domain and transmission to the customer. Similarly, the DSP  50  of the illustrated example processes a received upstream DSL signal to determined received bits that are subsequently sent via the switch fabric  48  and the uplink XCVR  46  to, for example, the backbone server.  
      To convert digital downstream DSL signals generated by the DSP  50  to analog signals suitable for transmission across a telephone line to a customer, each of the example analog modules  310  include an analog front end (AFE)  52 . The AFE  52  of the illustrated example also converts received analog upstream DSL signals to a digital form suitable for processing by the DSP  50 . In the illustrated example of  FIG. 2 , the AFE  52  includes an analog/digital converter  54  and a line driver (LD)  60 . As illustrated, the analog/digital converter  54  includes both a digital-to-analog converter (DAC)  56  and an analog-to-digital converter (ADC)  58 . The analog/digital converter  54  may additionally contain transmit and/or receive filters.  
      To provide, among other things, sufficient amplification and/or filtering such that an analog signal transmitted by an analog module  310  can be correctly received by a customer (e.g., by a DSL modem situated at the customer&#39;s location), each of the example analog modules  310  of  FIG. 2  include the LD  60 . The LD  60  may additionally provide amplification and/or filtering to receive and/or extract an analog signal transmitted by the customer. To protect the DSLAM, the analog modules  310  and/or the digital module  304  from environmental factors (e.g., lightning, short circuits, ground faults, power induction, etc.) each of the analog modules  310  of the illustrated example include an Isolation and Protection module and/or circuit  62 . In general, the Isolation and Protection module  62  limits the maximum voltage and/or current present on the end of the telephone lines closest to the analog module  310  by shunting excessive voltages and/or currents to ground. The maximum voltage and/or current is usually chosen to protect the telephone lines, the analog modules  310 , the DSLAM, and/or any person who may be nearby and/or in contact with the telephone lines, the analog modules  310  and/or the DSLAM. Example shunting devices include heat coils, fuses, carbon block protectors, gas tube protectors, and solid-state protectors.  
      In the illustrated example of  FIG. 2 , the telephone line  66  that connects the analog module  310  and the customer may simultaneously carry both POTS signals (i.e., telephone service signals) and the signals transmitted and/or received by the corresponding DSL modem (i.e., DSL signals). For example, DSL signals are typically transmitted above 20 kHz (20 thousand cycles per second) and, thus, do not interfere with POTS signals (which are typically transmitted below 3 kHz). To keep transients associated with POTS (e.g., ring voltages, ring trip transients, etc.) and DSL signals from interfering, each of the example analog modules  310  of the illustrated example include a POTS splitter  64 .  
      It will be readily apparent to persons of ordinary skill in the art that the uplink XCVR  46 , the switch fabric  48  and/or the DSP  50  process data and/or signals associated with one or more DSL modems (i.e., one or more customers). In particular, as illustrated in the example distributed DSLAM of  FIG. 2 , the DSP  50  (i.e., the digital module  305 ) is connected to the plurality of analog modules  310  that are associated with respective ones of the plurality of customers. However, a separate analog module  310  (e.g., an AFE  52 , a separate LD  60 , separate isolation and protection  62  and a separate POTS splitter  64 ) are provided for each DSL modem implemented by the example distributed DSLAM of  FIG. 2 .  
      To transport data and/or signals between the digital module  305  and the analog module(s)  310 , the example distributed DSLAM of  FIG. 2  includes a communication link  315  (e.g., a digital link  315 ). The communication link  315  may be implemented using any of a variety of suitable data transmission and/or communication technologies, methods and/or communication devices. For example, as described below in connection with  FIG. 3 , the communication link  315  may be implemented as a broadband communication link comprising a fiber optic cable and fiber optic transceivers. Additionally or alternatively, the communication link  315  may be implemented using bonded copper transport technology (e.g., based on the International Telecommunication Union (ITU) G.998 family of standards), for instance, Ethernet over copper (i.e., ITU G.998.2) as discussed below in connection with  FIG. 4 .  
      As discussed above, the digital module  305  may be shared among multiple analog modules  310 . In particular, the digital module  305  may communicate with a plurality of analog modules  310  using time-division multiplexing (TDM) for the digital link  315 . Having separated the digital module  305  from the analog module(s)  310 , the digital module  305  may be implemented anywhere within a communication system and/or network (e.g., it may be remote from the analog module(s)  310 ). In particular, the digital module  305  and the analog modules  310  may be implemented and/or located together and/or in physically separate and/or in different geographic locations. For example, the digital module  305  may be implemented in a central office and may communicate with a plurality of analog modules  310  located, for example, at one or more SAIs. Alternatively, the digital module  305  and the analog module(s)  310  may be co-located and/or implemented together. Additionally or alternatively, the digital module  305  and one or more analog modules  310  may be implemented in a same housing or in different housings. For example, a digital module  305  may be implemented together with a first analog module  310  in a first housing, while a second analog module  310  is implemented in a second housing. A digital module  305  may be implemented in one housing, and an analog module  310  implemented in a second housing, etc.  
      The example digital module  305  of  FIG. 2  may include more than one DSP  50  to allow the digital module  305  to support additional customers. Further, a service provider may implement a DSLAM containing multiple digital modules  305  and/or multiple digital links  315 . For example, the switch fabric  48  may route data received via the uplink XCVR  46  based on an address associated with each digital module  305  and/or each DSP  50 . For example, each DSP  50  may be assigned an Internet Protocol (IP) address, Ethernet may be used as the transmission protocol for the fiber optic link  41 , and/or the switch fabric  48  may implement a multi-port Ethernet switch using any of a variety of techniques.  
      In the illustrated example of  FIG. 2 , the DSPs  50  may be statically and/or dynamically assigned to the analog module(s)  310 . For instance, one DSP  50  may be assigned to one or more analog modules  310  located in a first SAI, while a second DSP  50  is assigned to one or more analog modules  310  located in a second SAI. Alternatively or additionally, each analog module  310  may be assigned to a DSP  50  and/or to a digital module  305  when an initial DSL service provided by the analog module  310  is configured and/or provisioned to provide the service. In this fashion, digital modules  305  may be deployed and/or installed as demand for DSL services increases and, thus, more efficiently share digital module  305  and/or DSP  50  resources across a larger number of analog modules  310 . For example, an analog module  310  may be installed and physically connected to each telephone line served by a SAI. When a service is requested on a telephone line, the analog module  310  for that telephone line may be appropriately configured and assigned to a digital module  305  based on any of a variety of business constraints or other criteria. For example the DSP  50  having the lowest current load and/or utilization could be selected, the DSP  50  could be selected upon the type of the requested DSL service, etc.  
      In the illustrated example of  FIG. 2 , the digital link  315  is implemented using TDM techniques. In particular, when an analog module  310  is associated with and/or assigned to a digital module  310 , one or more time slots on the digital link  315  are assigned to the analog module  310  and to the digital module  305 . The analog module  310  uses the assigned time slots on the digital link  315  to exchange data with the digital module  305 . It will be readily apparent to persons of ordinary skill in the art that alternative techniques may be used to implement the digital link  315 . For example, the digital link  315  may be implemented using any of a variety of packet based communication techniques, for example, Ethernet.  
       FIGS. 3 and 4  illustrate additional example distributed DSLAMs constructed in accordance with the teachings of the invention. Some components of the example distributed DSLAM of  FIG. 2  are the same as or substantially similar to corresponding components in the example distributed DSLAMs of  FIGS. 3 and 4 . In the interest of brevity, the descriptions of these corresponding elements, devices, circuits and/or components will not be repeated in connection with the description of the examples of  FIGS. 3 and 4 . Instead, the interested reader is referred back to the corresponding descriptions discussed above in connection with  FIG. 2 . To facilitate this process, corresponding elements in  FIGS. 2-4  have been numbered with like reference numerals.  
      The example distributed DSLAM of  FIG. 3  is partitioned into at least one universal access gateway (UAG)  405  and at least one local access gateway (LAG)  410 . In the example distributed DSLAM of  FIG. 3 , the UAG  405  includes one or more digital modules  305 , and the LAG  410  includes at least one analog interface  442  (i.e., an analog front end  442 , for example, the analog module  310 ).  
      To support Voice over IP (VoIP), the example UAG  405  of  FIG. 3  includes at least one VoIP DSP  415  in addition to at least one DSL DSP  50 . The VoIP DSP  415 , using any of a variety of techniques, converts data representative of digitized voice and/or audio into IP packets containing the digitized voice and/or audio that may be transmitted, for example, within a DSL service provided to a customer.  
      In the example DSLAM of  FIG. 3 , the uplink transceiver  46  may receive and transmit packets of information via the fiber link  42 . The packets of information may include digitized voice, digitized video, alphanumerical data such as documents and files, instant messaging, text messaging, and any other information and/or data. When information and/or data is received via the fiber link  42 , the uplink transceiver  46  provides the information to the switch fabric  48 , which may determine whether the information and/or data represents digitized voice by, for example, examining packet header information. If the information contains digitized voice, then the digitized voice may be provided to the VoIP DSP  415 . If the information contains non-voice information, it is provided to the DSL DSP  50 .  
      To form a digital stream that may be transported across the digital link  315  to one or more of the LAGs  410 , the example UAG  405  of  FIG. 3  includes any of a variety of serializer/deserializer (SerDes) devices  420 . The SerDes device  420 , using any of a variety of techniques, receives data from the one or more DSPs  50 ,  415  and serializes the data into one or more timeslots associated with the digital link  315 . The transceiver  425  then transmits the serialized data stream across the digital link  315  to one or more of the LAGs  410 . Similarly, the transceiver  425  receives a serialized data stream from the digital link  315  and the SerDes device  420  de-serializes the stream and passes data to an appropriate DSP  50 ,  415 .  
      To remotely configure the example UAG  405  of  FIG. 3  from, for example, an operations center, the UAG  405  includes a configurer  475 . The example configurer  475  of  FIG. 3  receives remote commands and/or control signals (e.g., electromagnetic signals) via the fiber optic link  42  and/or an external communications path  477 . For example, for commands received via the fiber optic link  42 , the configurer  475  could be assigned an IP address such that commands can be transmitted to the configurer  475  in IP packets and automatically routed to the configurer  475  via the switch fabric  48 . The external path  477  may be formed using any of a variety of techniques, for example, a first modem attached and/or a part of the UAG  405  and a second modem at an operations center. Based upon information, parameters and/or variables contained in the commands and/or control signals, the configurer  475  configures the digital module  305 , the VoIP DSP  415  and/or any LAGs  410  to which the UAG  405  is communicatively coupled. For instance, the configurer  475  could instruct one of the DSPs  50 ,  415  to send command and/or control information to the LAG  410  via the SerDes device  420  and the communication link  315 .  
      To receive data from, and to transmit data to, a UAG  405 , the example LAG  410  of  FIG. 3  includes a transceiver  430  and a SerDes device  435 . The implementation and operation of the transceiver  430  and the SerDes device  435  are similar to those described above in connection with the UAG  405 . In the illustrated example of  FIG. 3 , the digital link  315  is a broadband link implemented using a fiber optic link or a repeatered copper link (i.e., a series of copper cable connections and signal repeaters), wireless connection and/or other broadband links.  
      To route and/or switch data received via the digital link  315 , the example LAG  410  of  FIG. 3  includes a switch interface  440  (e.g., an Automated Cross Connect (ACC)  440 ). Based upon, for example, an assigned timeslot on the digital link  315 , the switch interface  440  routes received data associated with a DSL modem to a particular analog front end (AFE)  442  (e.g., to a specific digital/analog converter  450  and LD  455  etc.). Likewise, the ACC  440  routes data received by an AFE  442  into a particular timeslot on the digital link  315 . In the illustrated example of  FIG. 3 , the switch interface  440  may be statically and/or dynamically configured to route data to DSL modems (i.e., the AFEs  442 ).  
      Data received by the ACC  440  for a customer may include digitized voice, digitized video, alphanumerical data such as documents and files, instant messaging, text messaging, and any other information and/or data that is to be transmitted to the customer. For example, data for a first customer may represent both a downstream DSL signal and digitized voice (e.g., POTS signals) while data for a second customer may represent a downstream DSL signal containing packetized voice. To convert the digital data received by the ACC  440  into analog signals, the example LAG  410  includes one or more analog/digital converters  450  and one more line drivers  455  (i.e., one or more AFEs  442 ).  
      In the example LAG  410  of  FIG. 3 , the AFEs  442  are capable to simultaneously convert and/or combine both POTS signals and DSL signals. The analog/digital converters  450  and the line drivers  445  include, among other things, a subscriber line interface circuit (SLIC) and/or equivalent functionality. In an example, an output  460  contains both DSL signals residing, for example, above 20 kHz as well as POTS signals residing, for example, below 3 kHz, thus, eliminating the need for a POTS splitter (i.e., POTS+DSL). To provide standard POTS signaling, the example LAG  410  of  FIG. 3  also includes one or more POTS signaling circuits  460 . In a second example, an output  465  of the LAG  410  contains only DSL signals. In such an example, any voice data will be transported as packets by the DSL service (i.e., DSL+VOIP). While the example LAG  410  of  FIG. 3  does not illustrate a POTS signaling circuit  460  for the output  465 , persons of ordinary skill in the art will readily recognize that a POTS signaling circuit  460  may be implemented for each DSL modem, and that the POTS signaling circuit  460  may be bypassed and/or disabled when not required. Information received from a customer is processed by a LAG  410  and the UAG  405  using techniques similar to those described above.  
      As illustrated in  FIG. 3 , the ACC  440  may additionally provide a SerDes output  470  to allow multiple LAGs  410  to be stacked (i.e., co-located) and/or connected to one or more UAGs  405  via a shared digital link  315 .  
      In the illustrated example of  FIG. 3 , remote command signals may be sent from a server or any other suitable device, including a PDA, GUI, mobile telephone, computer workstation operations database, etc. via any suitable communication link, (including the Internet) to connect or disconnect any port (e.g., an analog front end) of a LAG  410  from its respective telephone line. For example, an analog/digital converter  450  and line driver  455  pair may be disabled to disconnect services for a customer via a remote command signal. Similarly, remote command signals may be used to, for example, configure the analog/digital converter  450  and line driver pair  455  to support either POTS+DSL or DSL+VoIP.  
      To remotely configure the example LAG  410  of  FIG. 3 , the LAG  410  includes a configurer  480 . The example configurer  480  of  FIG. 3  receives remote commands and/or control signals (e.g., electromagnetic signals) via the communication link  315  and/or an external communications path  482 . For example, commands could be received using one or more timeslots of the communication link  315  such that commands can be routed to the configurer  480  by the switch interface  440 . The external path  482  may be formed using any of a variety of techniques, for example, a first modem attached and/or a part of the LAG  410  and a second modem at an operations center. Based upon information, parameters and/or variables contained in the commands and/or control signals, the configurer  480  configures the switch interface  440  and the AFEs  442 .  
      In the illustrated example of  FIG. 3 , the UAG  405  and the LAGs  410  may be implemented and/or located together and/or in physically separate and/or in different geographic locations. For example, the UAG  405  may be implemented in a central office and may communicate with a plurality of LAGs  410  located, for example, at one or more SAIs. Alternatively, the UAG  405  and the LAG(s)  410  may be co-located and/or implemented together. Additionally or alternatively, the UAG  405  and one or more LAGs  410  may be implemented in a same housing or in different housings. For example, a UAG  405  may be implemented together with a first LAG  410  in a first housing, while a second UAG  405  is implemented in a second housing; a UAG  405  may be implemented in one housing, and an LAG  410  implemented in a second housing; etc.  
       FIG. 4  illustrates another example distributed DSLAM constructed in accordance with the teachings of the invention. The example distributed DSLAM of  FIG. 4  includes a universal access server (UAS)  505  and a remote terminal (RT)  510 . In the illustrated example of  FIG. 4 , the RT  510  includes a UAG  525  and at least one LAG  530 , and the UAS  505  and the RT  510  communicate via Ethernet over copper technology (e.g., according to the ITU G.998.2 standard). In particular, the UAS  505  and the RT  510  both include a bonded copper transport circuit  515 ,  520 . The operations of the remaining portions of  FIG. 4  are similar and/or identical to those described above in connection with  FIG. 3  and, thus, in the interest of brevity, a description of those operations will not be repeated here. Instead, the interested reader is referred to the corresponding description of  FIG. 3 . To facility this process, like portions of  FIGS. 3 and 4  are identified with identical reference numerals.  
      To remotely configure the RT  510 , the RT  510  includes a configurer  550 . The example configurer  550  of  FIG. 4  receives remote commands and/or control signals (e.g., electromagnetic signals) via an Ethernet over copper communication link  530  and/or an external communications path  552 . For example, for commands received via the Ethernet over copper communication link  530  the configurer  550  could be assigned and IP address such that commands can be transmitted to the configurer  550  in IP packets and automatically routed to the configurer  550  via the switch fabric  48 . The external path  552  may be formed using any of a variety of techniques, for example, a first modem attached and/or a part of the RT  510  and a second modem at an operations center. Based upon information, parameters and/or variables contained in the commands and/or control signals, the configurer  550  configures the UAG  525  and the LAGs  530 .  
       FIG. 5  illustrates mapping, cross-switching and/or cross-connecting one or more telephone lines to one or more signal processing modules thereby providing, for example, a DSL service to one or more telephone lines. As described above, a communication system and/or network may include one or more broadband content servers  605 , one or more digital modules  602  (e.g., digital modules  305 , UAGs  405  or UASs  505 ), a switching network  610 , and one or more analog interfaces  604  (e.g., analog modules  310 , LAGs  410  or RTs  510 ).  
      To connect a particular one of the digital modules  602 A to a particular one of the analog modules  604 A, the example system of  FIG. 5  includes a switching network  610 . The switching network  610  may be implemented using any of a variety of techniques and/or devices. For example, the switching network  610  may be implemented as a TDM cross-connect, a packet-based switched network, etc. For instance, the switching network  610  may be configured to connect a digital module  602 A to an analog module  604 A via a time slot of a digital link  315 A. Alternatively, the switching network  610  could use, for example, an IP address of an IP packet to route data between the digital module  602 A and the analog module  604 A.  
      It will be readily apparent to persons of ordinary skill in the art that the illustrated examples of  FIGS. 2-5  may be utilized, combined and/or augmented to implement a distributed DSLAM in any of a variety of ways. For example, a UAG  405  located in a central office may connect to a LAG  410  located at a SAI, a UAG  405  located in a central office may connect to a first LAG  410  located at a first SAI via a second LAG  410  located at a second SAI, a UAG  405  and a LAG  410  may be co-located in a central or serving office, a UAS  505  located in a central office may connect to a RT  510  located at a SAI. By reviewing the above examples, other additional examples will abound to persons of ordinary skill in the art.  
      It will also be readily apparent to persons of ordinary skill in the art that the example analog module  310 , the example LAG  410  and/or the example RT  510  may be implemented to have low power consumption and, thus, be line powered. That is, they may obtain power provided by a central office via, for example, a copper wire or a fiber optic cable. For example, when a LAG  410  is located in a SAI the LAG  410  may be substantially closer to the customer than if the LAG  410  were located in a central office. Thus the line driver may need to provide substantially less amplification, thereby consuming considerably less power.  
       FIG. 6  is yet another example manner of implementing a distributed DSLAM constructed in accordance with the teachings of the invention. Like the illustrated examples of  FIG. 2-4 , the example distributed DSLAM of  FIG. 6  may be implemented as more than one distinct and/or distributed components  240  and  250 . In particular, the illustrated example of  FIG. 6  includes a plurality of DSPs (e.g., DSP 1   242  through DSPN  244 ) each of which is coupled to a network (such as the Internet) via an Ethernet link or a backbone network and provide services for a plurality of customers. Each of the plurality of DSPs may be configured differently, and each may be coupled to provide one or more services to a group of customers.  
      To connect the plurality of DSPs to, for example, a plurality of analog interfaces (i.e., analog modules), the example DSLAM of  FIG. 6  includes a first switch interface (e.g., a switch matrix  246 ) and a second switch interface (e.g., a switch matrix  248 ) that implement a many-to-many digital switched network that may, for example, include dedicated switched connections, multiplexed signals, and/or addressed packets. Other possible implementations for the switch matrices  246  and  248  include, but are not limited to, CDMA and TDMA protocols. Encryption and frequent updating of routing, encryption keys and/or IP addresses may be used to prevent a customer from obtaining services that the communications company and/or service provider has not assigned to the customer.  
      To transmit signals to and receive signals from a plurality of subscribers, the component  250  includes, for example, the plurality of analog modules (e.g., analog modulel  252  through analog moduleN  254 ). In the illustrated example of  FIG. 6 , each of the plurality of analog modules is associated with respective ones of a plurality of subscribers.  
      As illustrated and discussed above in connection with  FIGS. 2-6 , a distributed DSLAM may be implemented in any of a variety of manners. In particular, a distributed DSLAM implementation may be chosen based upon one or more design and/or deployment criteria. For example, the UAG  405  and the LAG  410  may be co-located or remote from each other, the communication link  315  may be implemented to have different speeds and/or a different type, an implementation and/or type of analog front end  442  (e.g., DAC conversion speed), etc. Having reviewed the disclosed example distributed DSLAM implementations illustrated in  FIGS. 2-6 , a person of ordinary skill in the art will recognize that other examples abound.  
      In the illustrated example distributed DSLAMs of  FIGS. 2-4  and  6 , none of the example digital module  305 , the example UAG  405  or the example component  240  contain a digital/analog converter  54 ,  450 , a DAC  56 , an ADC  58 , a LD  60 ,  455 , a POTS splitter  64  or an isolation and protection circuit  62 . Similarly, the example analog modules  310  and the LAGs  410  of  FIGS. 2-4  and  6  do not include a signal processing device (e.g., the DSP  50 ,  415 ).  
      It will be readily apparent to persons of ordinary skill in the art that a distributed DSLAM may contain any of a variety of additional devices, components and/or functionality beyond those shown and discussed herein. For example, a distributed DSLAM may include any or all of a management and/or monitoring processor, a FLASH memory device, four-wire to two-wire hybrid circuits, etc. In the interest of brevity and clarity, such elements are not discussed herein. However, it is assumed that any such appropriate devices may be implemented by and/or within any distributed DSLAM.  
       FIGS. 7 and 8  are schematic illustrations of example communication systems constructed in accordance with the teachings of the invention. The example system of  FIG. 7  illustrates a UAG  262  associated with a central office  264  that is coupled to one or more LAGs  270  and  272  located at one or more SAIs  278  and  280 , respectively, via at least one broadband digital link. The UAG  262  is further coupled via second and third central and/or serving offices  266  and  268  to LAGs  274  and  276 , respectively. In the example illustrated in  FIG. 7 , the UAG  262  and the LAGs  278 ,  280 ,  282  and  284  are configured such that the UAG  262  may provide services to a plurality of customers  294 ,  296 ,  298  and  300  via a respective plurality of serving terminals  286 ,  288 ,  290  and  292 .  
      In contrast to the example prior art system of  FIG. 1 , the example system of  FIG. 8  incorporates one or more distributed DSLAMs and implements a remote link  905  between the operations center  22 , the central office  24 , the SAI  26  and the ST  28 . The remote link  905  can be used, for example, to remotely command and/or configure a UAG  305  and switching network  222  installed in the central office  24  and a LAG  310  installed in the SAI  26 , thereby eliminating a truck roll to configure a service for the customer  30 .  
       FIG. 9  illustrates a flowchart representative of example machine readable instructions that may be executed to configure the example distributed DSLAMs and/or the example systems of  FIGS. 2-8 . The example machine readable instructions of  FIG. 9  may be executed by a processor, a controller and/or any other suitable processing device. For example, the example machine readable instructions of  FIG. 9  may be embodied in coded instructions stored on a tangible medium such as a flash memory, or RAM associated with a processor (e.g., the processor  8010  shown in the example processor platform  8000  and discussed below in conjunction with  FIG. 10 ). Alternatively, some or all of the example machine readable instructions of  FIG. 9  may be implemented using an application specific integrated circuit (ASIC), a programmable logic device (PLD), a field programmable logic device (FPLD), discrete logic, hardware, firmware, etc. Also, some or all of the example machine readable instructions of  FIG. 9  may be implemented manually or as combinations of any of the foregoing techniques, for example, a combination of firmware and/or software and hardware. Further, although the example machine readable instructions of  FIG. 9  are described with reference to the flowcharts of  FIG. 9 , persons of ordinary skill in the art will readily appreciate that many other methods of configuring the example distributed DSLAMs and/or the example systems of  FIGS. 2-8  may be employed. For example, the order of execution of the blocks may be changed, and/or some of the blocks described may be changed, eliminated, sub-divided, or combined.  
      Execution of the example machine readable instructions of  FIG. 9  by, for example, a processor  8010  begins, for instance, in response to a customer requesting a new communication service (e.g., VoD via DSL). Persons of ordinary skill in the art will appreciate that, although for simplicity of illustration and discussion, the flowchart of  FIG. 9  shows one control path, requests may be queued and processed sequentially and/or processed in parallel by, for example, separate processing threads. The processor  8010  first determines the telephone line associated with the customer (i.e., connected to the customer&#39;s location) (block  705 ) and then determines, for example, the LAG  310  and the LAG  310  port (i.e., the analog interface and/or analog front end) connected to the telephone line (block  710 ). Next, using any of a variety of criteria, the processor  8010  selects a DSP  50  and a UAG  305  to provide the service (block  715 ), determines a digital link  315  connecting the LAG  310  and the selected DSP  50  (block  720 ), and selects and/or assigns a timeslot of the digital link to the customer (block  725 ). Based on the assigned timeslot and selected digital link  315 , the processor  8010  configures, for example, the switch network  222  to transport the assigned timeslot between the UAG  305  and the LAG  310  (block  730 ). The processor  8010  then configures the LAG  310  based upon one or more parameters associated with the requested service (e.g., DSL+POTS vs. DSL+VoIP, etc.) (block  735 ), configures the UAG  305  (block  740 ) and configures the broadband content servers (block  745 ).  
       FIG. 10  is a schematic diagram of an example processor platform  8000  that may be used and/or programmed to implement the example machine readable instructions illustrated in  FIG. 9  to configure the example DSLAMs and/or the systems of  FIGS. 2-8 . For example, the processor platform  8000  can be implemented by one or more general purpose microprocessors, microcontrollers, etc.  
      The processor platform  8000  of the example of  FIG. 10  includes a general purpose programmable processor  8010 . The processor  8010  executes coded instructions  8027  present in main memory of the processor  8010  (e.g., within a random access memory (RAM)  8025 ). The processor  8010  may be any type of processing unit, such as a microprocessor from the Intel®, AMD®, IBM®, or SUN® families of microprocessors. The processor  8010  may implement, among other things, the machine readable instructions of  FIG. 9  to configure the example DSLAMs and/or the examples systems of  FIGS. 2-8 .  
      The processor  8010  is in communication with the main memory (including a read only memory (ROM)  8020  and the RAM  8025 ) via a bus  8005 . The RAM  8025  may be implemented by dynamic random access memory (DRAM), Synchronous DRAM (SDRAM), and/or any other type of RAM device. The ROM  8020  may be implemented by flash memory and/or any other desired type of memory device. Access to the memory  8020  and  8025  is typically controlled by a memory controller (not shown) in a conventional manner.  
      The processor platform  8000  also includes a conventional interface circuit  8030 . The interface circuit  8030  may be implemented by any type of well-known interface standards, such as an external memory interface, serial port, general purpose input/output, etc. One or more input devices  8035  and one or more output devices  8040  are connected to the interface circuit  8030 .  
      Of course, persons of ordinary skill in the art will recognize that the order, size, and proportions of the memory illustrated in the example systems may vary. Additionally, although this patent discloses example systems including, among other components, software or firmware executed on hardware, it will be noted that such systems are merely illustrative and should not be considered as limiting. For example, it is contemplated that any or all of these hardware and software components could be embodied exclusively in hardware, exclusively in software, exclusively in firmware or in some combination of hardware, firmware and/or software. Accordingly, persons of ordinary skill in the art will readily appreciate that the above described examples are not the only way to implement such systems.  
      At least some of the above described example methods and/or apparatus are implemented by one or more software and/or firmware programs running on a computer processor. However, dedicated hardware implementations including, but not limited to, an ASIC, programmable logic arrays and other hardware devices can likewise be constructed to implement some or all of the example methods and/or apparatus described herein, either in whole or in part. Furthermore, alternative software implementations including, but not limited to, distributed processing or component/object distributed processing, parallel processing, or virtual machine processing can also be constructed to implement the example methods and/or apparatus described herein.  
      It should also be noted that the example software and/or firmware implementations described herein are optionally stored on a tangible storage medium, such as: a magnetic medium (e.g., a disk or tape); a magneto-optical or optical medium such as a disk; or a solid state medium such as a memory card or other package that houses one or more read-only (non-volatile) memories, random access memories, or other re-writable (volatile) memories; or a signal containing computer instructions. A digital file attachment to e-mail or other self-contained information archive or set of archives is considered a distribution medium equivalent to a tangible storage medium. Accordingly, the example software and/or firmware described herein can be stored on a tangible storage medium or distribution medium such as those described above or equivalents and successor media.  
      To the extent the above specification describes example components and functions with reference to particular devices, standards and/or protocols, it is understood that the teachings of the invention are not limited to such devices, standards and/or protocols. For instance, DSL, POTS, VoIP, IP, Ethernet over Copper, fiber optic links, DSPs, G.998.2 represent examples of the current state of the art. Such systems are periodically superseded by faster or more efficient systems having the same general purpose. Accordingly, replacement devices, standards and/or protocols having the same general functions are equivalents which are intended to be included within the scope of the accompanying claims.  
      Although certain example methods, apparatus and articles of manufacture have been described herein, the scope of coverage of this patent is not limited thereto. On the tent covers all methods, apparatus and articles of manufacture fairly falling of the appended claims either literally or under the doctrine of equivalents.