Abstract:
A method and system is provided for replacing a first set of line cards with new line cards. A call-processing unit (CPU) is provided that includes a primary memory unit and a secondary memory unit. A line-card holder is populated with a second set of line cards that are interfaced with the call-processing unit. Provision is made for the data that was being processed by the original set of line cards to be processed by the second set of line cards. Connectors that were originally connected to the one or more line cards are removed and coupled to the connectors to the set of temporary line cards, which facilitate data processing while the original line cards are replaced, at which point the process is reversed.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     TECHNICAL FIELD 
     This invention relates to the field of replacing or upgrading line cards associated with a communications network. 
     BACKGROUND 
     A common component in a telecommunications networking environment is the central office (“CO”). A central office can be a telephone-company building where subscriber lines are joined to switching equipment for connecting other subscribers to each other, local and long distance. Sometimes, a central office is a wire center in which there might be several switching exchanges. In this case, there will be switches, cable-distribution frames, batteries, air-conditioning and heating systems, etc. But a central office may sometimes be a single telephone switch, what may be referred to in Europe as a public exchange. 
     A component common in a central office is a line gateway frame. Although perhaps referred to by various names in the telecommunications industry, a line gateway frame houses multiple line cards. A line card is an electronic printed circuit card that operates lamps, ringing, holding, and other such features associated with one or several telephone lines or telephones in a telephone system. It can also refer to a device that transmits and receives optical data and converts optical signals to and from electrical signals. Line cards may transmit multiple data streams to and from other line cards. Typically, line cards plug into switches, cross-connects, multiplexors, and routers that form the building blocks of communications networks. 
     Over time for various reasons, these line cards may need to be replaced with new line cards. Old line cards may become technologically obsolete, damaged through user error, or corrupted from natural causes such as lightning, and consequently, for whatever reason, need to be replaced. 
     In some situations, line cards need to be replaced en masse; that is, more than one at a time, even a whole shelf or frame at a time. But replacing line cards is currently a time-and resource-intensive process that can take on the order of 10 to 15 minutes to replace a single card. During this time frame associated with replacing a line card, the customers who are serviced by the line card will be without telephone communications service. Thus, business owners, residents, and possibly even emergency personnel will not have access to their phones and other services while one or more line cards associated with their services are being replaced. The current state of the art could be improved by providing, among other things, a way to reduce customer downtime that stems from having to replace old line cards with new line cards. 
     SUMMARY 
     The present invention is described by the claims below. Various embodiments of the invention include an improved method for changing out old line cards with new line cards associated with a telecommunication networking environment. The present invention has several practical applications in the technical arts including substantially reducing the time that customers are without service while one or more line cards need to be changed and decreasing the time associated with changing line cards. The time that customers are without service can be reduced from the order of 10-15 minutes to the order of a few seconds. 
     In a first aspect of an embodiment of the present invention, a method is provided for replacing a first set of line cards with new line cards. The method includes providing a call-processing unit that includes a primary memory unit and a secondary memory unit, populating a line-card holder, such as a line gateway frame, with a second set of line cards that are interfaced with the call-processing unit; providing for the data that was being processed by the original set of line cards to be processed by the second set of line cards; removing the connectors that were originally connected to the one or more line cards; and coupling the connectors to the set of temporary line cards. 
     In a second aspect, a method for replacing line cards associated with a communications network is provided. The method includes providing a data file that includes information about customer services associated with a first set of line cards that are ultimately to be replaced by a set of new line cards. The first set of line cards transmit and receive data through respective connectors that are connected to the first set of line cards. The method includes providing a set of temporary line cards that are coupled to a wire-connecting device that is also coupled to the first set of line cards. Both sets of line cards are also coupled to a call-processing unit that has a primary processor and a standby processor. If the primary processor is synchronized with the standby processor, then the method includes desynchronizing the primary processor from the standby processor and associating with the standby processor the information about the customer services. One way of associating the standby processor with the information about the customer services is to upload a data file that includes information about the customer services to the standby processor. The standby processor is caused to enter into an active state while the primary processor is caused to enter into a standby state. The connectors that were originally connected to the original line cards are then coupled to the set of temporary line cards. The original line cards are then replaced with a new set of line cards while the temporary line cards service the customers that were associated with the original line cards. The standby processor is then caused to revert back into a standby state and the primary processor is caused to revert to an active state. Finally, the original connectors that were coupled to the original line cards are then connected to the new line cards. 
     In a final illustrative aspect, a method is provided for upgrading line cards that are associated with a communications network. The method includes temporarily routing data that was serviced by the line cards to a set of temporary line cards; enabling the temporary line cards to route the data that was being serviced by the original line cards; replacing the line cards with new line cards; and rerouting the data to flow through the new line cards. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The present invention is described in detail below with reference to the attached drawing figures, which are incorporated by reference herein and wherein: 
         FIG. 1  depicts an exemplary operating environment suitable for practicing an embodiment of the present invention; 
         FIG. 1A  depicts processors or memory components of a call-processing unit operating in a desynchronized state (and later resynchronized); 
         FIG. 2  depicts in greater detail an illustrative line gateway frame and spare line gateway shelf suitable for use in an embodiment of the present invention; and 
         FIG. 3  is a flow chart depicting an illustrative method for practicing an embodiment of the present invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As briefly mentioned in the Background section, a customer&#39;s telephone line is supported in a carrier&#39;s central office by a port on a line card. The line card is essentially a printed circuit board that may contain one or many ports through which the customers are provided dial tone and various other services. The mapping of the customer&#39;s telephone number and subscribed services to the dedicated line-card port occurs in a call-processing unit (CPU). 
     Turning now to  FIG. 1 , an illustrative operating environment suitable for practicing an embodiment of the present invention is provided. The operating environment includes an illustrative customer facility  110  having one or more endpoints  112 . Endpoint  112  is coupled to a wire-connecting device  114  by line  116  commonly through a network  118 . In this embodiment, wire-connecting device  114  takes the form of a distribution frame, or more particularly the main distribution frame. The main distribution frame provides the ability to connect subscribers to the correct ports of a central office. Similarly, cables coming in from many PBX extensions need to connect to the PBX. The cables could be directly wired to the central office or to the PBX, but this would be inflexible. Future moves and changes would be very difficult. Thus, a solution is what is referred to as a distribution frame. 
     Distribution frame  114  is a wire-connecting device. It does not necessarily require electronics to operate. On one side of the distribution frame may be wires coming in from the outside world, such as line  116 . On the other side, wires are terminated coming in from the CO or PBX. Both wires are connected with wire that is commonly referred to as a jumper wire. By pulling off one end of the jumper wire and moving it to another location, customer serving equipment can be quickly changed, cabling can be added or subtracted, and other repairs are made more feasible. In large central offices, distribution frame  114  may span whole city blocks and the jumper wires can be several hundred yards long. 
     Distribution frame  114  is coupled to a line gateway frame  120 . The line gateway frame houses a set of line gateway shelves, such as illustrative gateway shelf  122 , which house a number of line cards, collectively referenced by numeral  124 . Additional details with respect to line gateway frame  120  will be provided with reference to  FIG. 2 . 
     Line gateway frame  120  is coupled to a call-processing unit  126 . The call-processing unit may include multiple processors and/or multiple storage components associated with those processors. To not obscure the present invention, a primary processor  128  is shown with an associated primary memory unit  130 . Also shown is a standby processor  132  associated with a standby memory unit  134 . Call-processing unit  126  facilitates the mapping of customer telephone numbers and their subscribed services to a dedicated line-card port. CPU  126  analyzes digits dialed by the customer and affects routing to other devices such as another line in the central office or to a customer in another central office reachable via communications network  136 , which may be the same as networks  138  and  118 , but do not have to be. A call-processing unit can be a system and process that sets up the intended connection in a switching system. The unit can scan various trunks and/or station ports for any requests for service. Upon detecting a request, CPU  126  checks stored instructions, such as those that may be stored in storage components  130  or  134 , and sets the connection up accordingly. 
     CPU  126  may be accessed via a local interface component, such as interface component  140 , or remotely through a network such as network  138  via remote interface component  142 . In a first operating condition, processors  128  and  132  are synchronized as are memory components  130  and  134  to process calls. But the depiction provided in  FIG. 1  should not be construed as limiting in nature, but is intentionally shown simplistically to not obscure the present invention. In other embodiments, two active processors may be present along with one standby processor. The processors are always active, but memory functionality may be offered by what is referred to as shared memory. Thus, when processor  128  is desynchronized from  132 , or when memory component  130  is desynchronized from standby memory component  134 , each operates independently.  FIG. 1A  illustrates a desynchronization and resynchronization of the processors, which can be extrapolated to include the memory components. 
     Desynchronization between processors is depicted by numeral  144 , which indicates that primary processor  128  can be desynchronized from standby processor  132 . Similarly, primary memory unit  130  may become desynchronized from standby memory unit  134 , which can then receive a data file  146 , which may store information associated with various communications services for one or more customers. That the processors and memory may be resynchronized is depicted by reference numeral  148 . Network  136  may be coupled to many hundreds or thousands of customers illustratively represented by numeral  150 . 
     CPU  126  and line gateway frame  120  are shown coupled to a trunk gateway  152 , which is a component that provides access to network  136 , which may be the public switched telephone network (PSTN), and provides service to customers  150 . Main distribution frame  114 , CPU  126 , trunk gateway  152 , and line gateway frame  120  are illustratively shown housed in a central office  154 . 
     Turning now to  FIG. 2 , additional detail of line gateway frame  120  and a line gateway shelf such as line gateway shelf  122  is provided. As shown, line gateway frame  120  can include a set of line-card holders, such as line gateway shelf  122 . Line gateway frame  120  is illustratively depicted as either having multiple line gateway shelves, depending upon nomenclature that is common to those of ordinary skill in the art. For clarification purposes, a first line gateway shelf is referenced by numeral  122 A, and a spare line gateway shelf is referenced by numeral  122 B. But both shelves  122 A and  122 B are of the type referenced generally by numeral  122  referring to a generic line gateway shelf. Turning to line gateway shelf  122 A, the shelf typically has mounting slots for multiple line gateway cards. In this generic depiction sixteen line gateway cards are provided. In actuality from 1 to many line gateway cards may be equipped in a line gateway shelf. A specific line card is referenced by numeral  164 . Line card  164  is not unique among the set of line cards  124  but, again, is labeled purely for referential purposes. Line card  164  includes an input/output port  166 . In actuality, line card  164  may have many ports such as 1, 2, 4, 8, 16, 32, etc., ports. A cable  170  couples the line card in shelf  122 A to a line block on distribution frame  114 . 
     Spare line gateway shelf  122 B may be independent of line gateway frame  120  or an available shelf within line gateway frame  120 . It too includes one or more line cards and corresponding cables such as cable  176  in this depiction for coupling it to distribution frame  184 . Spare line gateway shelf  122 B is depicted generally as being associated with a removed connector  178 . 
     In operation, the cards of spare line gateway shelf  122 B are used to temporarily service customers  112  while the line cards of in-service shelf  122 A are being replaced. Thus, rather than the downtime being equal in duration to the amount of time associated with physically replacing and reconfiguring the line cards of shelf  122 A, the only downtime is that associated with coupling the connectors of shelf  122 A to the cards of shelf  122 B, which is significantly shorter. 
     Turning now to  FIG. 3 , an illustrative method for changing line cards according to an embodiment of the present invention is provided and referenced generally by the numeral  310 . At a step  312 , a conversion set is created. Conversion set  312  includes information about customers, their respective services, and the corresponding line cards associated with providing those services to the customer. Returning briefly to  FIG. 1 , data file  146  is an illustrative conversion set. Thus, creating conversion set  146  includes in one embodiment creating a data file that lists line cards to be replaced, customers associated with the line cards that will be affected by their replacement, and possibly other data such as the services associated with those customers. 
     Process  310  begins with both processors of CPU  126  and the memory unit synchronized. When the processors  132  and  128  are synchronized with each other, then both operate to service and process data associated with the various customers such as customers  112 . At a step  314 , a set of temporary line cards is provided in an available line gateway shelf. For purposes of this example, assume cards  162  of original shelf  122 A are to be replaced with a new set of cards not shown. Cards  174  of spare line gateway shelf  122 B will be used to service and process the data that was being serviced by card set  162 . 
     At a step  316 , temporary line cards  174  are prepared for service transfer, which entails temporarily servicing the customers via cards  174  that were serviced by cards  162 . Preparing cards  174  includes configuring the cards to mirror the functionality offered by cards  162 , which are to be replaced. This can be done via a graphical user interface such as interface  140  or  142 . A line administration graphical user interface provides a means for an administrator to initiate commands to prepare the temporary cards  174  to service customers  112 , which in this example are illustratively assumed to be serviced by cards  162 . 
     At a step  318  an actual data file, such as file  146 , is prepared using the conversion set created in step  312 . The file is prepared to be loaded into CPU standby memory component  134 . At a step  320 , the shared memory of CPU  126  is desynchronized into an active memory component and a standby memory component. For example, memory component  130  may be the active memory component, which continues to service customers  112 , while memory component  134  is relegated to a standby status, wherein it may not continue to service customers  112 . This desynchronization step may be accomplished in a variety of ways. For instance, those skilled in the art may also appreciate that the processors of CPU  126  may be desynchronized. In this embodiment, processor  128  is desynchronized from processor  132 , such that processor  128  may be in an active state while processor  132  may be in a standby state. In either case, the thrust of what is being accomplished is to free a resource that will be able to receive new call-instruction data in real time while customers currently serviced by CPU  126  continue to receive their service. 
     With the shared memory of CPU  126  desynchronized from each other, data file  146  is loaded into standby memory component  134  at a step  322 . This step is also referenced in  FIG. 1A  by numeral  322 . Now standby processor  132  is associated with a memory component  134  that houses the information necessary for temporary line cards  174  to service customers  112 . This being the case, the standby memory is ready to become active and take over processing from primary processor  128 , which is associated with primary memory component  130 . 
     Accordingly, at a step  324 , standby memory component  134  and standby processor  132  are transitioned from a standby state to an active state. It is common for a small duration of time to be associated with effecting this change. That is, there is a gap between when the command is issued to place the standby processor  132  and memory component  134  into an active state and vice versa for processor  128  and memory component  130  and actually have that change occur. For the sake of efficiency, this is an opportune time to make the necessary physical wiring adjustments between the original cards  162  and temporary cards  174 . 
     At a step  326 , preferably during step  324  while the primary processors and standby processors swap state, the connectors that were connected to old cards  162  are removed and coupled to temporary cards  174 . This can happen in a variety of ways. In a first embodiment, a connector such as connector  168  may be directly connected to a port on one of the line cards from the set  174 . In an alternative embodiment, a jumper cable  180  is employed to couple connector  168  to a corresponding port on a line card in set  174 . In a still another embodiment, jumper cable  181  is employed to couple connector  179  on the line cable from a corresponding port on a line card in set  174  to line block  114  where the terminations are made to connect to customers  112 . After about the time associated with making the physical line-card changes, temporary line cards  174  will begin servicing customers  112 . The time associated with this is on the order of 1 to 2 minutes or as small as a few seconds. Thus, customers  112  “experience” a service outage on the order of seconds. 
     Line cards  162  are no longer servicing customers  112 . Thus, the technician can replace old line cards  162  with the new line cards (not shown) in bulk. That is, a technician may replace all of the line cards in set  162  at the same time rather than having to serially replace each individual line card. In the prior art, replacing line cards in bulk like this would not have been feasible because customers would experience an outage for as long as it would take to replace the entire shelf. But given the advantage of the present invention, a technician may replace an entire shelf or more at a time. Thus, at a step  328 , the old cards  162  are locked down. At a step  330 , old line cards  162  are replaced with new line cards. The new line cards can then all be unlocked at a step  332 , which is known and understood by one of ordinary skill in the art. 
     At a step  334 , provisions are made for what is now the current standby memory or processor to be reactivated (and the current active processor/memory to be reverted to standby status). Thus, processor  128  is reverted back to an active status as is memory component  130 . At the same time, processor  132  is reverted to a standby status as is memory component  134 . As with the last instance, while the active and standby processors are being swapped, the original connectors associated with the old line cards  162  (such as connector  168 ) are attached to the newly installed line cards. After a short while, the preprogrammed new line cards will come online and begin servicing customers  112 . Again, the customers  112  only experience a brief outage for a few moments while standby processors and active processors are again swapped. So while the CPU change is in progress, the line cards associated with  122 A are brought online having been re-connected to connector(s)  168 . Finally the processors are re-synchronized removing the temporary data  146  and returning to normal operation on the newly replaced cards. A software command to read in a journal file for any changes during activities can be completed and dial tones checked. Those skilled in the art may appreciate alternative ways of implementing various embodiments of the present invention without departing from the scope of the claims below, which define the invention.