Patent Publication Number: US-11394481-B1

Title: Efficient processing of time-division multiplexing based signals

Description:
TECHNICAL FIELD 
     The present disclosure relates to computer networking. 
     BACKGROUND 
     Several existing technologies can transport frames/packets over a bundle of interfaces/Time-Division Multiplexing (TDM) circuits. Ethernet over Synchronous Optical Networking (SONET)/Synchronous Digital Hierarchy (SDH) (EoS) combined with Virtual Concatenation (VCAT) allows for transporting Ethernet frames over a bundle of multiple Synchronous Transport Signal (STS) circuits/Virtual Circuits (VCs). For example, add/drop multiplexers can use EoS to transport frame-based Generic Framing Protocol-Framed (GFP-F) encapsulated Ethernet frames across a 622 Mbps large “pipe” formed by bundling 4×STS3c (SONET) or 4× VC4 (SDH). Several circuit sizes and bundle members can be chosen to adjust to given bandwidth needs. Similarly, Ethernet over Plesiochronous Digital Hierarchy (PDH) (EoPDH) can be used to carry Ethernet frames over bundled low-speed PDH circuits/interfaces (e.g., Nx VT15). In the router field, bundling DS1/E1 interfaces using Multi-Link Point-to-Point Protocol (MLPPP) or Multi-Link Frame Relay (MLFR) can help carry packets over larger pipes. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates a block diagram of a system configured to efficiently process TDM based signals, according to an example embodiment. 
         FIG. 2  illustrates a block diagram of a system configured to efficiently process TDM based signals including protection and backup components, according to an example embodiment. 
         FIG. 3  illustrates a block diagram of the system of  FIG. 2  with a circuit path failure, according to an example embodiment. 
         FIG. 4  illustrates a block diagram of the system of  FIG. 2  with a TDM card failure, according to an example embodiment. 
         FIG. 5  illustrates a flowchart of a method for performing functions associated with operations discussed herein, according to an example embodiment. 
         FIG. 6  illustrates a flowchart of another method for performing functions associated with operations discussed herein, according to an example embodiment. 
     
    
    
     DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Overview 
     Techniques are described herein for efficient processing of TDM based signals. In one example embodiment, a system includes a first TDM card, a second TDM card, and a processor in communication with the first TDM card and the second TDM card. The second TDM card hosts an aggregation process configured to aggregate a first TDM based signal and a second TDM based signal into a combined TDM based signal. The processor is configured to obtain a packetized version of the first TDM based signal from the first TDM card and provide the packetized version of the first TDM based signal to the second TDM card. The processor is further configured to prompt one or more packet cards to output packets based on the combined TDM based signal. 
     Example Embodiments 
       FIG. 1  illustrates a block diagram of system  100 , which may include a network node (e.g., router) and/or a converged Circuit Emulation (CEM) and routing system. System  100  includes TDM cards  110 ( 1 )- 110 ( 3 ), processor  120 , and packet cards  130 ( 1 ) and  130 ( 2 ). TDM cards  110 ( 1 )- 110 ( 3 ) may be TDM trunk cards, and processor  120  may be a Network Processing Unit (NPU). 
     System  100  is configured to obtain TDM based signals  140 ( 1 )- 140 ( 3 ) from a source (e.g., a network or the cloud), convert TDM based signals  140 ( 1 )- 140 ( 3 ) to packets  150 ( 1 ) and  150 ( 2 ), and provide packets  150 ( 1 ) and  150 ( 2 ) to a destination (e.g., a network or the cloud). Packets  150 ( 1 ) and  150 ( 2 ) may be encapsulated/decapsulated based on the content of TDM based signals  140 ( 1 )- 140 ( 3 ). 
     System  100  is also configured to obtain packets  150 ( 1 ) and  150 ( 2 ) from a source (e.g., a network or the cloud), convert packets  150 ( 1 ) and  150 ( 2 ) to TDM based signals  140 ( 1 )- 140 ( 3 ), and provide TDM based signals  140 ( 1 )- 140 ( 3 ) to a destination (e.g., a network or the cloud). The process of converting packets  150 ( 1 ) and  150 ( 2 ) to TDM based signals  140 ( 1 )- 140 ( 3 ) may be referring to as “de-packetizing” packets  150 ( 1 ) and  150 ( 2 ). 
     TDM based signals  140 ( 1 )- 140 ( 3 ) may include bitstreams carried in circuits  160 ( 1 )- 160 ( 3 ), respectively. In this example, circuits  160 ( 1 )- 160 ( 3 ) are part of a single circuit bundle, meaning that circuits  160 ( 1 )- 160 ( 3 ) belong to the same flow but have been separated into different circuits. For instance, consider a scenario in which a customer purchases a 1 GE physical interface to connect to the cloud. In this scenario, circuits  160 ( 1 )- 160 ( 3 ) may each have a bandwidth capacity of 150 Mbits. If the customer purchases three 150 Mbit increments of bandwidth capacity, circuits  160 ( 1 )- 160 ( 3 ) would be bundled for the customer to provide a total bandwidth capacity of 450 Mbits. 
     Conventional techniques would not enable system  100  to accurately packetize TDM based signals  140 ( 1 )- 140 ( 3 ) or de-packetize packets  150 ( 1 ) and  150 ( 2 ). This is because conventional techniques cannot provide a single point of aggregation (or dis-aggregation) for circuits  160 ( 1 )- 160 ( 3 ). In a classic TDM add/drop multiplexer, multiple circuits would enter the multiplexer via multiple TDM trunk ports/cards and cross-connect to a single client card that performs VCAT/GFP. However, system  100  includes multiple packet cards (i.e., packets cards  130 ( 1 ) and  130 ( 2 )), rather than a single client card. In a traditional CEM/routing system, a VCAT engine would reside on each TDM trunk card, and all circuits in a bundle would be required to enter the system on the same TDM card. But system  100  includes multiple circuits  160 ( 1 )- 160 ( 3 ) that enter and exit system  100  via respective TDM cards  110 ( 1 )- 110 ( 3 ). 
     Thus, to aggregate or disaggregate circuits  160 ( 1 )- 160 ( 3 ), conventional techniques would require TDM based signals  140 ( 1 )- 140 ( 3 ) to enter or exit system  100  on the same TDM card, where aggregation or disaggregation would occur. However, in system  100 , TDM based signals  140 ( 1 )- 140 ( 3 ) enter and exit on respective TDM cards  110 ( 1 )- 110 ( 3 ). Accordingly, signal aggregation logic  170  and signal aggregation logic  180 ( 1 ) are provided in processor  120  and TDM card  110 ( 1 ), respectively. Signal aggregation logic  170  and  180 ( 1 ) may enable system  100  to aggregate and/or disaggregate TDM based signals  140 ( 1 )- 140 ( 3 ) while permitting TDM based signals  140 ( 1 )- 140 ( 3 ) to arrive at and exit from respective TDM cards  110 ( 1 )- 110 ( 3 ). 
     As a result, system  100  may allow unprotected circuit bundles to arrive at and exit from multiple TDM cards. In particular, system  100  may provide flexibility to map any suitable circuit  160 ( 1 )- 160 ( 3 ) to any suitable TDM card  110 ( 1 )- 110 ( 3 ). As explained in greater detail below in connection with  FIGS. 2-4 , these techniques may also enable redundancies of circuits  160 ( 1 )- 160 ( 3 ) for protection. 
     In the example of  FIG. 1 , TDM card  110 ( 1 ) is nominated to aggregate TDM based signals  140 ( 1 )- 140 ( 3 ) using aggregation process  190 ( 1 ). Aggregation process  190 ( 1 ), which is hosted on TDM card  110 ( 1 ), is configured to aggregate TDM based signals  140 ( 1 )- 140 ( 3 ) into a combined TDM based signal. Aggregation process  190 ( 1 ) may perform any suitable operations to re-join the circuit bundle into one flow. This may include packet/frame de-skew, re-ordering, and any other suitable aggregation operations. 
     As shown, TDM card  110 ( 1 ) obtains TDM based signal  140 ( 1 ) via circuit  160 ( 1 ) and terminates TDM based signal  140 ( 1 ) directly into aggregation process  190 ( 1 ). Meanwhile, circuits  160 ( 2 ) and  160 ( 3 )—which arrive at TDM cards  110 ( 2 ) and  110 ( 3 ), respectively—are redirected via internal emulation flows across processor  120  to TDM card  110 ( 1 ). In this example, processor  120  and packet cards  130 ( 1 ) and  130 ( 2 ) are configured to handle packets; as a result, TDM cards  110 ( 1 )- 110 ( 3 ) may be configured to packetize (or de-packetize) TDM based signals  140 ( 1 )- 140 ( 3 ). 
     Specifically, TDM card  110 ( 2 ) may obtain TDM based signal  140 ( 2 ) via circuit  160 ( 2 ), packetize TDM based signal  140 ( 2 ), and provide the packetized version of TDM based signal  140 ( 2 ) to processor  120 . Processor  120  may obtain the packetized version of TDM based signal  140 ( 2 ) and provide the packetized version of TDM based signal  140 ( 2 ) to TDM card  110 ( 1 ). Similarly, TDM card  110 ( 3 ) may obtain TDM based signal  140 ( 3 ) via circuit  160 ( 3 ), packetize TDM based signal  140 ( 3 ), and provide the packetized version of TDM based signal  140 ( 3 ) to processor  120 . Processor  120  may obtain the packetized version of TDM based signal  140 ( 3 ) and provide the packetized version of TDM based signal  140 ( 3 ) to TDM card  110 ( 1 ). 
     TDM card  110 ( 1 ) may obtain the packetized versions of TDM based signals  140 ( 2 ) and  140 ( 3 ) from processor  120 , de-packetize the packetized versions of TDM based signals  140 ( 2 ) and  140 ( 3 ) to recover TDM based signals  140 ( 2 ) and  140 ( 3 ), and provide TDM based signals  140 ( 2 ) and  140 ( 3 ) to aggregation process  190 ( 1 ). At this point, aggregation process  190 ( 1 ) has obtained TDM based signals  140 ( 1 )- 140 ( 3 ). Accordingly, TDM card  110 ( 1 ) may aggregate, by aggregation process  190 ( 1 ), TDM based signals  140 ( 1 )- 140 ( 3 ) into a combined TDM based signal. 
     TDM card  110 ( 1 ) may further prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  150 ( 1 ) and  150 ( 2 ) based on the combined TDM based signal. In particular, TDM card  110 ( 1 ) may extract/decapsulate packets  150 ( 1 ) and  150 ( 2 ) from the combined TDM based signal and provide packets  150 ( 1 ) and  150 ( 2 ) to processor  120  based on sequence numbers of packets  150 ( 1 ) and  150 ( 2 ). Processor  120  may, in turn, prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  150 ( 1 ) and  150 ( 2 ) based on the combined TDM based signal by providing packets  150 ( 1 ) and  150 ( 2 ) to packet cards  130 ( 1 ) and  130 ( 2 ). 
     TDM card  110 ( 1 ) may also be configured to disaggregate a combined TDM based signal into TDM based signals  140 ( 1 )- 140 ( 3 ) using aggregation process  190 ( 1 ). In this example, TDM based signals  140 ( 1 )- 140 ( 3 ) include outgoing TDM based signals, and packets  150 ( 1 ) and  150 ( 2 ) include incoming packets. Packets cards  130 ( 1 ) and  130 ( 2 ) obtain packets  150 ( 1 ) and  150 ( 2 ) and provide packets  150 ( 1 ) and  150 ( 2 ) to processor  120 , which in turn obtains packets  150 ( 1 ) and  150 ( 2 ) and provides packets  150 ( 1 ) and  150 ( 2 ) to TDM card  110 ( 1 ). 
     TDM card  110 ( 1 ) obtains packets  150 ( 1 ) and  150 ( 2 ) and generates an outgoing combined TDM based signal based on (e.g., by encapsulating) packets  150 ( 1 ) and  150 ( 2 ). TDM card  110 ( 1 ) further generates TDM based signals  140 ( 1 )- 140 ( 3 ) based on packets  150 ( 1 ) and  150 ( 2 ). For example, TDM card  110 ( 1 ) may generate TDM based signals  140 ( 1 )- 140 ( 3 ) from the outgoing combined TDM based signal using a round-robin mechanism. 
     TDM card  110 ( 1 ) may directly output TDM based signal  140 ( 1 ) via circuit  160 ( 1 ). TDM card  110 ( 1 ) may further packetize TDM based signals  140 ( 2 ) and  140 ( 3 ) and provide the packetized versions of TDM based signals  140 ( 2 ) and  140 ( 3 ) to processor  120 . Processor  120  may obtain the packetized versions of TDM based signals  140 ( 2 ) and  140 ( 3 ), provide the packetized version of TDM based signal  140 ( 2 ) to TDM card  110 ( 2 ), and provide the packetized version of TDM based signal  140 ( 3 ) to TDM card  110 ( 3 ). TDM cards  110 ( 2 ) and  110 ( 3 ) may de-packetize the packetized versions of TDM based signals  140 ( 2 ) and  140 ( 3 ) to recover TDM based signals  140 ( 2 ) and  140 ( 3 ) and output TDM based signals  140 ( 2 ) and  140 ( 3 ) via circuits  160 ( 2 ) and  160 ( 3 ), respectively. 
     Thus, system  100  may be operable in both directions (i.e., TDM based signals  140 ( 1 )- 140 ( 3 ) to packets  150 ( 1 ) and  150 ( 2 ), and packets  150 ( 1 ) and  150 ( 2 ) to TDM based signals  140 ( 1 )- 140 ( 3 )). In the former direction, system  100  may terminate a circuit bundle, extract packets  150 ( 1 ) and  150 ( 2 ) (and/or frames), and cause packets  150 ( 1 ) and  150 ( 2 ) to be sent out from packet cards  130 ( 1 ) and  130 ( 2 ). For instance, if each circuit  160 ( 1 )- 160 ( 3 ) carries 150 Mbits, the individual 150 Mbit bitstreams may be aggregated into a combined TDM signal by aggregating three smaller time slots corresponding to each of circuits  160 ( 1 )- 160 ( 3 ) to a single, bigger time slot, and packets  150 ( 1 ) and  150 ( 2 ) may be extracted from the combined TDM signal. Conversely, in the latter direction, packets  150 ( 1 ) and  150 ( 2 ) may be converted to a combined TDM signal, which is mapped to the bigger time slot, and the combined TDM signal may be spread across circuits  160 ( 1 )- 160 ( 3 ) in the three smaller time slots. 
     Therefore, system  100  may enable packet transport over circuit bundles by processing network traffic for a bundle of circuits  160 ( 1 )- 160 ( 3 ) arriving at or exiting from respective TDM cards  110 ( 1 )- 110 ( 3 ). System  100  may form a circuit bundle (and a protection group, as explained in greater detail below in connection with  FIGS. 2-4 ) without restricting circuits  160 ( 1 )- 160 ( 3 ) to a single TDM port/channel of TDM cards  110 ( 1 )- 110 ( 3 ). 
     TDM card  110 ( 1 ), TDM card  110 ( 2 ), and/or processor  120  may comprise one or more tangible (non-transitory) computer readable storage media (e.g., a memory device) encoded with software comprising computer executable instructions. When the software is executed (e.g., by TDM card  110 ( 1 ), TDM card  110 ( 2 ), and/or processor  120 ), the software may be operable to perform operations described herein. In particular, TDM card  110 ( 1 ), TDM card  110 ( 2 ), and/or processor  120  include signal aggregation logic  170 ,  180 ( 1 ), and/or  180 ( 2 ), respectively. When executed, signal aggregation logic  170 ,  180 ( 1 ), and/or  180 ( 2 ) enable TDM card  110 ( 1 ), TDM card  110 ( 2 ), and/or processor  120  to perform techniques described herein. 
     Any suitable technology may be used in accordance with the techniques described herein. System  100  may implement Optical Transport Networking (OTN), SONET (e.g., Ethernet over SONET), SDH, PDH (e.g., Ethernet over PDH), and other time slot based mechanisms. Packet cards  130 ( 1 ) and  130 ( 2 ) may have corresponding Ethernet ports. In one example, aggregation process  190 ( 1 ) may be a Virtual Concatenation (VCAT) process that performs GFP-F functions. In another example, aggregation process  190 ( 1 ) may be a multi-link aggregation process, such as an MLPPP process or an MLFR process. 
     Furthermore, these techniques may apply to any suitable converged TDM/packet system(s). TDM cards  110 ( 1 )- 110 ( 3 ) may be part of a single system/router or belong to multiple systems/routers. While system  100  includes only three TDM cards (i.e., TDM cards  110 ( 1 )- 110 ( 3 )), the techniques described herein may be compatible with any suitable number of TDM cards. Moreover, while aggregation process  190 ( 1 ) is provided in TDM card  110 ( 1 ), in other examples aggregation process  190 ( 1 ) may be provided on TDM card  110 ( 2 ), TDM card  110 ( 3 ), or any other suitable entity (e.g., TDM card, chip, etc.) configured to perform circuit bundle aggregation (and/or disaggregation) functions. 
     With continuing reference to  FIG. 1 ,  FIG. 2  illustrates a block diagram of an example system  200  configured to efficiently process TDM based signals including protection and backup components. System  200  includes TDM cards  210 ( 1 ),  210 ( 2 ), and  110 ( 3 ), processor  120 , and packet cards  130 ( 1 ) and  130 ( 2 ). Processor  120 , TDM card  210 ( 1 ), and TDM card  210 ( 2 ) include signal aggregation logic  170 ,  180 ( 1 ), and  180 ( 2 ), respectively. 
     Signal aggregation logic  170 ,  180 ( 1 ), and  180 ( 2 ) may enable system  200  to provide redundancy protection for TDM based signals  140 ( 1 )- 140 ( 3 ) and/or aggregation process  190 ( 1 ) by leveraging traffic redirection between TDM cards  210 ( 1 ),  210 ( 2 ), and  110 ( 3 ) using emulation and per—circuit bundle redundancy pairs. This may help maintain uninterrupted and efficient packet processing over circuit bundles even in the event of a circuit or TDM card failure. Any suitable redundancy protection technique(s) may be employed on a group or individual basis, such as Unidirectional Path Switch Ring (UPSR), Subnetwork Connection Protection (SNCP), Automatic Protection Switching (APS), Multiplex Section Protection (MSP), etc. 
     In addition to obtaining TDM based signals  140 ( 1 )- 140 ( 3 ), system  200  is also configured to obtain TDM based signals  220 ( 1 )- 220 ( 3 ). TDM based signal  220 ( 1 ) may be a copy of TDM based signal  140 ( 2 ); TDM based signal  220 ( 2 ) may be a copy of TDM based signal  140 ( 3 ); and TDM based signal  220 ( 3 ) may be a copy of TDM based signal  140 ( 1 ). TDM based signals  220 ( 1 )- 220 ( 3 ) may be carried in circuits  230 ( 1 )- 230 ( 3 ), respectively. 
     In one example, system  200  uses TDM based signals  140 ( 1 )- 140 ( 3 ) by default and switches over to one or more of TDM based signals  220 ( 1 )- 220 ( 3 ) in the event of a circuit or TDM card failure. As a result, TDM based signals  140 ( 1 )- 140 ( 3 ) may be referred to as working TDM based signals, and TDM based signals  220 ( 1 )- 220 ( 3 ) may be referred to as protection TDM based signals. Similarly, circuits  160 ( 1 )- 160 ( 3 ) may be referred to as working circuits, and circuits  230 ( 1 )- 230 ( 3 ) may be referred to as protection circuits. 
     Additionally, TDM card  210 ( 1 ) hosts aggregation process  190 ( 1 ), and TDM card  210 ( 2 ) hosts aggregation process  190 ( 2 ). Aggregation process  190 ( 2 ) may be similar or identical to aggregation process  190 ( 1 ). In one example, system  200  uses aggregation process  190 ( 1 ) by default and switches over to aggregation process  190 ( 2 ) when TDM card  210 ( 1 )—which hosts aggregation process  190 ( 1 )—fails. As a result, aggregation process  190 ( 1 ) may be referred to as a working aggregation process, and aggregation process  190 ( 2 ) may be referred to as a backup aggregation process. 
     Both TDM cards  210 ( 1 ) and  210 ( 2 ) may obtain all the working and protection circuits either directly or through CEM via processor  120 . TDM cards  210 ( 1 ) and  210 ( 2 ) include circuit selectors  240 ( 1 )- 240 ( 3 ) and  240 ( 4 )- 240 ( 6 ), respectively, which choose a working or protection circuit to feed into aggregation process  190 ( 1 ) (instantiated on TDM card  110 ( 1 )) or aggregation process  190 ( 2 ) (instantiated on TDM card  210 ( 1 )). Circuit selectors  240 ( 1 ) and  240 ( 4 ) are configured to choose between TDM based signal  140 ( 1 ) and TDM based signal  220 ( 3 ); circuit selectors  240 ( 2 ) and  240 ( 5 ) are configured to choose between TDM based signal  140 ( 2 ) and TDM based signal  220 ( 1 ); and circuit selectors  240 ( 3 ) and  240 ( 6 ) are configured to choose between TDM based signal  140 ( 3 ) and TDM based signal  220 ( 2 ). 
     In one example, both aggregation process  190 ( 1 ) and  190 ( 2 ) process the working and/or protection circuits obtained from circuit selectors  240 ( 1 )- 240 ( 3 ) and  240 ( 4 )- 240 ( 6 ) and provide corresponding packets  150 ( 1 ),  150 ( 2 ),  250 ( 1 ), and  250 ( 2 ) to processor  120 . Processor  120  may choose which of packets  150 ( 1 ),  150 ( 2 ),  250 ( 1 ), and  250 ( 2 ) to provide to packet cards  130 ( 1 ) and  130 ( 2 ). In this example, processor  120  may choose packets  150 ( 1 ) and  150 ( 2 ), which originated from aggregation process  190 ( 1 ), which is the working aggregation process. 
     As shown, TDM card  210 ( 1 ) obtains TDM based signal  140 ( 1 ) and terminates TDM based signal  140 ( 1 ) directly into circuit selector  240 ( 1 ). TDM card  210 ( 1 ) also obtains TDM based signal  220 ( 1 ) and terminates TDM based signal  220 ( 1 ) directly into circuit selector  240 ( 2 ). Meanwhile, circuits  160 ( 2 ) and  230 ( 2 ), which arrive at TDM card  210 ( 2 ), and circuits  160 ( 3 ) and  230 ( 3 ), which arrive at TDM card  110 ( 3 ), are redirected via internal CEM flows across processor  120  to TDM card  210 ( 1 ). 
     Specifically, TDM card  210 ( 2 ) may obtain TDM based signals  140 ( 2 ) and  220 ( 2 ) via circuits  160 ( 2 ) and  230 ( 2 ), respectively; packetize TDM based signals  140 ( 2 ) and  220 ( 2 ); and provide the packetized version of TDM based signals  140 ( 2 ) and  220 ( 2 ) to processor  120 . Processor  120  may obtain the packetized version of TDM based signals  140 ( 2 ) and  220 ( 2 ) and provide the packetized version of TDM based signals  140 ( 2 ) and  220 ( 2 ) to TDM card  210 ( 1 ). Similarly, TDM card  110 ( 3 ) may obtain TDM based signals  140 ( 3 ) and  220 ( 3 ) via circuits  160 ( 3 ) and  230 ( 3 ), respectively; packetize TDM based signals  140 ( 3 ) and  220 ( 3 ); and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to processor  120 . Processor  120  may obtain the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to TDM card  210 ( 1 ). 
     TDM card  210 ( 1 ) may obtain the packetized versions of TDM based signals  140 ( 2 ),  220 ( 2 ),  140 ( 3 ), and  220 ( 3 ) from processor  120  and de-packetize the packetized versions of TDM based signals  140 ( 2 ),  220 ( 2 ),  140 ( 3 ), and  220 ( 3 ) to recover TDM based signals  140 ( 2 ),  220 ( 2 ),  140 ( 3 ), and  220 ( 3 ). TDM card  210 ( 1 ) may provide TDM based signal  140 ( 2 ) to circuit selector  240 ( 2 ); TDM based signals  220 ( 2 ) and  140 ( 3 ) to circuit selector  240 ( 2 ); and TDM based signal  220 ( 3 ) to circuit selector  240 ( 1 ). 
     At this point, circuit selector  240 ( 1 ) has obtained TDM based signal  140 ( 1 ) and TDM based signal  220 ( 3 ); circuit selector  240 ( 2 ) has obtained TDM based signal  140 ( 2 ) and TDM based signal  220 ( 1 ); and circuit selector  240 ( 3 ) has obtained TDM based signal  140 ( 3 ) and TDM based signal  220 ( 2 ). Using circuit selector  240 ( 1 ), TDM card  210 ( 1 ) selects one of TDM based signal  140 ( 1 ) and TDM based signal  220 ( 3 ) (here, TDM based signal  140 ( 1 )). Using circuit selector  240 ( 2 ), TDM card  210 ( 1 ) selects one of TDM based signal  140 ( 2 ) and TDM based signal  220 ( 1 ) (here, TDM based signal  140 ( 2 )). And using circuit selector  240 ( 3 ), TDM card  210 ( 1 ) selects one of TDM based signal  140 ( 3 ) and TDM based signal  220 ( 2 ) (here, TDM based signal  140 ( 3 )). TDM based signals  140 ( 1 )- 140 ( 3 ) may be chosen over TDM based signals  220 ( 1 )- 220 ( 3 ) because TDM based signals  140 ( 1 )- 140 ( 3 ) are working TDM based signals and TDM based signals  220 ( 1 )- 220 ( 3 ) are protection TDM based signals.  FIG. 2  shows the selected signals as solid lines and the non-selected signals as dashed lines. 
     TDM card  210 ( 1 ) provides TDM based signals  140 ( 1 )- 140 ( 3 ) to aggregation process  190 ( 1 ). Accordingly, TDM card  210 ( 1 ) may aggregate, by aggregation process  190 ( 1 ), TDM based signals  140 ( 1 )- 140 ( 3 ) into a combined TDM based signal. TDM card  210 ( 1 ) may further prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  150 ( 1 ) and  150 ( 2 ) based on the combined TDM based signal. In particular, TDM card  210 ( 1 ) may extract/decapsulate packets  150 ( 1 ) and  150 ( 2 ) from the combined TDM based signal and provide packets  150 ( 1 ) and  150 ( 2 ) to processor  120  based on sequence numbers of packets  150 ( 1 ) and  150 ( 2 ). Processor  120  may, in turn, prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  150 ( 1 ) and  150 ( 2 ) based on the combined TDM based signal by providing packets  150 ( 1 ) and  150 ( 2 ) to packet cards  130 ( 1 ) and  130 ( 2 ). 
     TDM card  210 ( 1 ) may also be configured to disaggregate a combined TDM based signal into TDM based signals  140 ( 1 )- 140 ( 3 ) using aggregation process  190 ( 1 ). In this example, TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 ) include outgoing TDM based signals, and packets  150 ( 1 ) and  150 ( 2 ) include incoming packets. Packets cards  130 ( 1 ) and  130 ( 2 ) obtain packets  150 ( 1 ) and  150 ( 2 ), and provide packets  150 ( 1 ) and  150 ( 2 ) to processor  120 , which in turn obtains packets  150 ( 1 ) and  150 ( 2 ) and provides packets  150 ( 1 ) and  150 ( 2 ) to TDM card  210 ( 1 ). 
     TDM card  210 ( 1 ) obtains packets  150 ( 1 ) and  150 ( 2 ) and generates an outgoing combined TDM based signal based on (e.g., by encapsulating) packets  150 ( 1 ) and  150 ( 2 ). TDM card  210 ( 1 ) further generates TDM based signals  140 ( 1 )- 140 ( 3 ) based on packets  150 ( 1 ) and  150 ( 2 ). For example, TDM card  210 ( 1 ) may generate TDM based signals  140 ( 1 )- 140 ( 3 ) from the outgoing combined TDM based signal using a round-robin mechanism. 
     TDM card  210 ( 1 ) may duplicate TDM based signals  140 ( 1 )- 140 ( 3 ) (e.g., using circuit selectors  240 ( 1 )- 240 ( 3 )) to generate TDM based signals  220 ( 1 )- 220 ( 3 ). TDM card  210 ( 1 ) may directly output TDM based signal  140 ( 1 ) via circuit  160 ( 1 ) and TDM based signal  220 ( 1 ) via circuit  230 ( 1 ). TDM card  210 ( 1 ) may further packetize TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ) and provide the packetized versions of TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ) to processor  120 . 
     Processor  120  may obtain the packetized versions of TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ), provide the packetized version of TDM based signals  140 ( 2 ) and  220 ( 2 ) to TDM card  210 ( 2 ), and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to TDM card  110 ( 3 ). TDM cards  210 ( 2 ) and  110 ( 3 ) may de-packetize the packetized versions of TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ) to recover TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ) and output TDM based signals  140 ( 2 ),  140 ( 3 ),  220 ( 2 ), and  220 ( 3 ) via circuits  160 ( 2 ),  160 ( 3 ),  230 ( 2 ), and  230 ( 3 ), respectively. Thus, system  200  may be operable in both directions (i.e., TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 ) to packets  150 ( 1 ) and  150 ( 2 ), and packets  150 ( 1 ) and  150 ( 2 ) to TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 )). 
     TDM card  210 ( 2 ) may also be configured to aggregate TDM based signals  140 ( 1 )- 140 ( 3 ) and/or TDM based signals  220 ( 1 )- 220 ( 3 ) into a combined TDM based signal using aggregation process  190 ( 2 ). As shown, TDM card  210 ( 2 ) obtains TDM based signal  140 ( 2 ) and terminates TDM based signal  140 ( 2 ) directly into circuit selector  240 ( 5 ). TDM card  210 ( 2 ) also obtains TDM based signal  220 ( 2 ) and terminates TDM based signal  220 ( 2 ) directly into circuit selector  240 ( 6 ). Circuits  160 ( 1 ) and  230 ( 1 ), which arrive at TDM card  210 ( 1 ), and circuits  160 ( 3 ) and  230 ( 3 ), which arrive at TDM card  110 ( 3 ), are redirected via internal CEM flows across processor  120  to TDM card  210 ( 2 ). 
     Specifically, TDM card  210 ( 1 ) may obtain TDM based signals  140 ( 1 ) and  220 ( 1 ) via circuits  160 ( 1 ) and  230 ( 1 ), respectively; packetize TDM based signals  140 ( 1 ) and  220 ( 1 ); and provide the packetized version of TDM based signals  140 ( 1 ) and  220 ( 1 ) to processor  120 . Processor  120  may, in turn, obtain the packetized version of TDM based signals  140 ( 1 ) and  220 ( 1 ) and provide the packetized version of TDM based signals  140 ( 1 ) and  220 ( 1 ) to TDM card  210 ( 2 ). Similarly, TDM card  110 ( 3 ) may obtain TDM based signals  140 ( 3 ) and  220 ( 3 ) via circuits  160 ( 3 ) and  230 ( 3 ), respectively; packetize TDM based signals  140 ( 3 ) and  220 ( 3 ); and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to processor  120 . Processor  120  may, in turn, obtain the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to TDM card  210 ( 2 ). 
     TDM card  210 ( 2 ) may obtain the packetized versions of TDM based signals  140 ( 1 ),  220 ( 1 ),  140 ( 3 ), and  220 ( 3 ) from processor  120  and de-packetize the packetized versions of TDM based signals  140 ( 1 ),  220 ( 1 ),  140 ( 3 ), and  220 ( 3 ) to recover TDM based signals  140 ( 1 ),  220 ( 1 ),  140 ( 3 ), and  220 ( 3 ). TDM card  210 ( 2 ) may provide TDM based signals  140 ( 1 ) and  220 ( 3 ) to circuit selector  240 ( 4 ); TDM based signal  220 ( 1 ) to circuit selector  240 ( 5 ); and TDM based signal  140 ( 3 ) to circuit selector  240 ( 6 ). 
     At this point, circuit selector  240 ( 4 ) has obtained TDM based signal  140 ( 1 ) and TDM based signal  220 ( 3 ); circuit selector  240 ( 5 ) has obtained TDM based signal  140 ( 2 ) and TDM based signal  220 ( 1 ); and circuit selector  240 ( 6 ) has obtained TDM based signal  140 ( 3 ) and TDM based signal  220 ( 2 ). Using circuit selector  240 ( 4 ), TDM card  210 ( 2 ) selects one of TDM based signal  140 ( 1 ) and TDM based signal  220 ( 3 ) (here, TDM based signal  140 ( 1 )). Using circuit selector  240 ( 5 ), TDM card  210 ( 2 ) selects one of TDM based signal  140 ( 2 ) and TDM based signal  220 ( 1 ) (here, TDM based signal  140 ( 2 )). And using circuit selector  240 ( 6 ), TDM card  210 ( 2 ) selects one of TDM based signal  140 ( 3 ) and TDM based signal  220 ( 2 ) (here, TDM based signal  140 ( 3 )).  FIG. 2  shows the selected signals as solid lines and the non-selected signals as dashed lines. 
     TDM card  210 ( 2 ) provides TDM based signals  140 ( 1 )- 140 ( 3 ) to aggregation process  190 ( 2 ). Accordingly, TDM card  210 ( 2 ) may aggregate, by aggregation process  190 ( 2 ), TDM based signals  140 ( 1 )- 140 ( 3 ) into a backup combined TDM based signal. TDM card  210 ( 2 ) may extract/decapsulate packets  250 ( 1 ) and  250 ( 2 ) from the backup combined TDM based signal and provide packets  250 ( 1 ) and  250 ( 2 ) to processor  120  based on sequence numbers of packets  250 ( 1 ) and  250 ( 2 ). Because processor  120  is already prompting packets cards  130 ( 1 ) and  130 ( 2 ) to output packets  150 ( 1 ) and  150 ( 2 ), and because packets  150 ( 1 ) and  150 ( 2 ) may be identical to packets  250 ( 1 ) and  250 ( 2 ), processor  120  may intentionally drop packets  250 ( 1 ) and  250 ( 2 ) instead of sending packets  250 ( 1 ) and  250 ( 2 ) to packet cards  130 ( 1 ) and  130 ( 2 ). In other examples, however, processor  120  may send both packets  150 ( 1 ) and  150 ( 2 ) and packets  250 ( 1 ) and  250 ( 2 ) to packet cards  130 ( 1 ) and  130 ( 2 ), e.g., for packet redundancy. 
     While system  200  includes both working/protection circuits and a backup aggregation process, certain systems may include only one of the working/protection circuits and the backup aggregation process. Systems that include working/protection circuits may be protected when a specific working circuit fails; systems that include a backup aggregation process on a separate TDM card may be protected when the TDM card hosting the working aggregation process fails. Certain systems, such as system  100 , may not necessarily include either working/protection circuits or a backup aggregation process. Thus, inclusion of working/protection circuits and/or a backup aggregation process may be optional. 
     With continuing reference to  FIGS. 1 and 2 ,  FIG. 3  illustrates a block diagram of system  200  with a circuit path failure. In particular, circuit  160 ( 1 ) has failed, meaning that TDM card  210 ( 1 ) is no longer receiving TDM based signal  140 ( 1 ). In response to the failure, circuit  230 ( 3 ) becomes active and circuit selector  240 ( 1 ) opts to feed TDM based signal  220 ( 3 ) to aggregation process  190 ( 1 ). As discussed above in connection with  FIG. 2 , TDM based signal  220 ( 3 ) arrived at TDM card  110 ( 3 ) via circuit  230 ( 3 ) and was redirected by processor  120  to TDM card  210 ( 1 ). Aggregation process  190 ( 1 ) may thus maintain aggregation operations by combining TDM based signals  140 ( 2 ) and  140 ( 3 ) with TDM based signal  220 ( 3 ) in place of TDM based signal  140 ( 1 ). 
     With continued reference to  FIGS. 1 and 2 ,  FIG. 4  illustrates a block diagram of system  200  with a TDM card failure. In particular, TDM card  210 ( 1 ) has failed, meaning that aggregation process  190 ( 1 ) is no longer aggregating TDM based signals  140 ( 1 )- 140 ( 3 ). As a result, processor  120  is no longer receiving packets  150 ( 1 ) and  150 ( 2 ) from TDM card  210 ( 1 ), as represented by dashed lines  410 ( 1 ) and  410 ( 2 ). Also, although TDM based signals  140 ( 1 ) and  220 ( 1 ) are continuing to arrive at TDM card  210 ( 1 ), TDM card  210 ( 1 ) is no longer sharing TDM based signals  140 ( 1 ) or  220 ( 1 ) with TDM cards  210 ( 2 ) or  110 ( 3 ) via processor  120  using CEM. 
     In response to the failure of TDM card  210 ( 1 ), aggregation process  190 ( 2 ) may become active. Aggregation process  190 ( 2 ) previously had access to all circuit traffic streams (i.e., TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 )) and was aggregating TDM based signals  140 ( 1 )- 140 ( 3 ). Because TDM card  210 ( 1 ) has failed, the working path of circuit  160 ( 1 ) was impacted and TDM based signal  140 ( 1 ) (as well as TDM based signal  220 ( 1 )) is no longer available to aggregation process  190 ( 2 ). 
     Therefore, circuit selector  240 ( 4 ) provides TDM based signal  220 ( 3 )—instead of TDM based signal  140 ( 1 )—to aggregation process  190 ( 2 ). Circuit selectors  240 ( 5 ) and  240 ( 6 ) continue to provide TDM based signals  140 ( 2 ) and  140 ( 3 ), respectively, to aggregation process  190 ( 2 ). Using aggregation process  190 ( 2 ), TDM card  210 ( 2 ) aggregates TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 ) into a backup combined TDM based signal. Thus, system  200  may implement a protection switch from circuit  160 ( 1 ) to circuit  230 ( 3 ), but may refrain from implementing a circuit state protection change for circuits  160 ( 2 ) or  160 ( 3 ). 
     TDM card  210 ( 2 ) may prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  250 ( 1 ) and  250 ( 2 ) based on the combined TDM based signal. For example, TDM card  210 ( 2 ) may extract/decapsulate packets  250 ( 1 ) and  250 ( 2 ) from the combined TDM based signal and provide packets  250 ( 1 ) and  250 ( 2 ) to processor  120  based on sequence numbers of packets  250 ( 1 ) and  250 ( 2 ). Processor  120  may, in turn, prompt packet cards  130 ( 1 ) and  130 ( 2 ) to output packets  250 ( 1 ) and  250 ( 2 ) based on the combined TDM based signal by providing packets  250 ( 1 ) and  250 ( 2 ) to packet cards  130 ( 1 ) and  130 ( 2 ). 
     TDM card  210 ( 2 ) may also be configured to disaggregate a combined TDM based signal into TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 ) using aggregation process  190 ( 2 ). In this example, TDM based signals  140 ( 1 )- 140 ( 3 ) and  220 ( 1 )- 220 ( 3 ) include outgoing TDM based signals, and packets  250 ( 1 ) and  250 ( 2 ) include incoming packets. Packets cards  130 ( 1 ) and  130 ( 2 ) obtain packets  250 ( 1 ) and  250 ( 2 ) and provide packets  250 ( 1 ) and  250 ( 2 ) to processor  120 . Processor  120 , in turn, obtains packets  250 ( 1 ) and  250 ( 2 ) and provides packets  250 ( 1 ) and  250 ( 2 ) to TDM card  210 ( 2 ). 
     Upon obtaining packets  250 ( 1 ) and  250 ( 2 ), TDM card  210 ( 2 ) may generate an outgoing combined TDM based signal based on (e.g., by encapsulating) packets  250 ( 1 ) and  250 ( 2 ). TDM card  210 ( 2 ) may further generate TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 ) based on the outgoing combined TDM based signal. For example, TDM card  210 ( 2 ) may generate TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 ) from the outgoing combined TDM based signal using a round-robin mechanism. 
     TDM card  210 ( 2 ) may duplicate TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 ) (e.g., using circuit selectors  240 ( 1 )- 240 ( 3 )) to generate TDM based signals  140 ( 1 ),  220 ( 1 ), and  220 ( 2 ). TDM card  210 ( 2 ) may directly output TDM based signal  140 ( 2 ) via circuit  160 ( 2 ) and TDM based signal  220 ( 2 ) via circuit  230 ( 2 ). TDM card  210 ( 2 ) may further packetize TDM based signals  140 ( 1 ),  140 ( 3 ),  220 ( 1 ), and  220 ( 3 ). TDM card  210 ( 2 ) may provide the packetized versions of TDM based signals  140 ( 1 ),  140 ( 3 ),  220 ( 1 ), and  220 ( 3 ) to processor  120 . 
     Processor  120  may obtain the packetized versions of TDM based signals  140 ( 1 ),  140 ( 3 ),  220 ( 1 ), and  220 ( 3 ), provide the packetized version of TDM based signals  140 ( 1 ) and  220 ( 1 ) to TDM card  210 ( 1 ), and provide the packetized version of TDM based signals  140 ( 3 ) and  220 ( 3 ) to TDM card  110 ( 3 ). Alternatively, processor  120  may choose not to provide the packetized version of TDM based signals  140 ( 1 ) and  220 ( 1 ) to TDM card  110 ( 1 ) because TDM card  110 ( 1 ) has failed and therefore cannot de-packetize the packetized versions of TDM based signals  140 ( 1 ) and  220 ( 1 ). TDM card  110 ( 3 ) may de-packetize the packetized versions of TDM based signals  140 ( 3 ) and  220 ( 3 ) to recover TDM based signals  140 ( 3 ) and  220 ( 3 ) and output TDM based signals  140 ( 3 ) and  220 ( 3 ) via circuits  160 ( 3 ) and  230 ( 3 ), respectively. Thus, system  200  may be operable in both directions (i.e., TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 ) to packets  250 ( 1 ) and  250 ( 2 ), and packets  250 ( 1 ) and  250 ( 2 ) to TDM based signals  220 ( 3 ),  140 ( 2 ), and  140 ( 3 )). 
       FIG. 5  is a flowchart of an example method  500  for performing functions associated with operations discussed herein. Method  500  may be performed by any suitable entity, such as a processor (e.g., processor  120 ). At operation  510 , the processor may obtain a packetized version of a first TDM based signal from a first TDM card. At operation  520 , the processor may provide the packetized version of the first TDM based signal to a second TDM card that hosts an aggregation process configured to aggregate the first TDM based signal and a second TDM based signal into a combined TDM based signal. At operation  530 , the processor may prompt one or more packet cards to output packets based on the combined TDM based signal. 
       FIG. 6  is a flowchart of an example method  600  for performing functions associated with operations discussed herein. Method  600  may be performed by any suitable entity, such as a TDM card (e.g., TDM cards  110 ( 1 ) or  210 ( 1 )). At operation  610 , the TDM card may obtain a packetized version of a first TDM based signal from a processor that obtained the packetized version of the first TDM based signal from a first TDM card (e.g., TDM cards  110 ( 2 ),  110 ( 3 ), or  210 ( 2 )). At operation  620 , the TDM card may obtain a second TDM based signal. At operation  630 , the TDM card may aggregate, by an aggregation process, the first TDM based signal and the second TDM based signal into a combined TDM based signal. At operation  640 , the TDM card may prompt one or more packet cards to output packets based on the combined TDM based signal. 
     Embodiments described herein may include one or more networks, which can represent a series of points and/or network elements of interconnected communication paths for receiving and/or transmitting messages (e.g., packets of information) that propagate through the one or more networks. These network elements offer communicative interfaces that facilitate communications between the network elements. A network can include any number of hardware and/or software elements coupled to (and in communication with) each other through a communication medium. Such networks can include, but are not limited to, any Local Area Network (LAN), Virtual LAN (VLAN), Wide Area Network (WAN) (e.g., the Internet), Software Defined WAN (SD-WAN), Wireless Local Area (WLA) access network, Wireless Wide Area (WWA) access network, Metropolitan Area Network (MAN), Intranet, Extranet, Virtual Private Network (VPN), Low Power Network (LPN), Low Power Wide Area Network (LPWAN), Machine to Machine (M2M) network, Internet of Things (IoT) network, Ethernet network/switching system, any other appropriate architecture and/or system that facilitates communications in a network environment, and/or any suitable combination thereof. 
     Networks through which communications propagate can use any suitable technologies for communications including wireless communications (e.g., 4G/5G/nG, IEEE 802.11 (e.g., Wi-Fi®/Wi-Fi6®), IEEE 802.16 (e.g., Worldwide Interoperability for Microwave Access (WiMAX)), Radio-Frequency Identification (RFID), Near Field Communication (NFC), Bluetooth™ mm.wave, Ultra-Wideband (UWB), etc.), and/or wired communications (e.g., T1 lines, T3 lines, digital subscriber lines (DSL), Ethernet, Fibre Channel, etc.). Generally, any suitable means of communications may be used such as electric, sound, light, infrared, and/or radio to facilitate communications through one or more networks in accordance with embodiments herein. Communications, interactions, operations, etc. as discussed for various embodiments described herein may be performed among entities that may be directly or indirectly connected utilizing any algorithms, communication protocols, interfaces, etc. (proprietary and/or non-proprietary) that allow for the exchange of data and/or information. 
     In various example implementations, entities for various embodiments described herein can encompass network elements (which can include virtualized network elements, functions, etc.) such as, for example, network appliances, forwarders, routers, servers, switches, gateways, bridges, load-balancers, firewalls, processors, modules, radio receivers/transmitters, or any other suitable device, component, element, or object operable to exchange information that facilitates or otherwise helps to facilitate various operations in a network environment as described for various embodiments herein. Note that with the examples provided herein, interaction may be described in terms of one, two, three, or four entities. However, this has been done for purposes of clarity, simplicity and example only. The examples provided should not limit the scope or inhibit the broad teachings of systems, networks, etc. described herein as potentially applied to a myriad of other architectures. 
     Communications in a network environment can be referred to herein as ‘messages’, ‘messaging’, ‘signaling’, ‘data’, ‘content’, ‘objects’, ‘requests’, ‘queries’, ‘responses’, ‘replies’, etc. which may be inclusive of packets. As referred to herein and in the claims, the term ‘packet’ may be used in a generic sense to include packets, frames, segments, datagrams, and/or any other generic units that may be used to transmit communications in a network environment. Generally, a packet is a formatted unit of data that can contain control or routing information (e.g., source and destination address, source and destination port, etc.) and data, which is also sometimes referred to as a ‘payload’, ‘data payload’, and variations thereof. In some embodiments, control or routing information, management information, or the like can be included in packet fields, such as within header(s) and/or trailer(s) of packets. Internet Protocol (IP) addresses discussed herein and in the claims can include any IP version 4 (IPv4) and/or IP version 6 (IPv6) addresses. 
     To the extent that embodiments presented herein relate to the storage of data, the embodiments may employ any number of any conventional or other databases, data stores or storage structures (e.g., files, databases, data structures, data or other repositories, etc.) to store information. 
     Note that in this Specification, references to various features (e.g., elements, structures, nodes, modules, components, engines, logic, steps, operations, functions, characteristics, etc.) included in ‘one embodiment’, ‘example embodiment’, ‘an embodiment’, ‘another embodiment’, ‘certain embodiments’, ‘some embodiments’, ‘various embodiments’, ‘other embodiments’, ‘alternative embodiment’, and the like are intended to mean that any such features are included in one or more embodiments of the present disclosure, but may or may not necessarily be combined in the same embodiments. Note also that a module, engine, client, controller, function, logic or the like as used herein in this Specification, can be inclusive of an executable file comprising instructions that can be understood and processed on a server, computer, processor, machine, compute node, combinations thereof, or the like and may further include library modules loaded during execution, object files, system files, hardware logic, software logic, or any other executable modules. 
     It is also noted that the operations and steps described with reference to the preceding figures illustrate only some of the possible scenarios that may be executed by one or more entities discussed herein. Some of these operations may be deleted or removed where appropriate, or these steps may be modified or changed considerably without departing from the scope of the presented concepts. In addition, the timing and sequence of these operations may be altered considerably and still achieve the results taught in this disclosure. The preceding operational flows have been offered for purposes of example and discussion. Substantial flexibility is provided by the embodiments in that any suitable arrangements, chronologies, configurations, and timing mechanisms may be provided without departing from the teachings of the discussed concepts. 
     As used herein, unless expressly stated to the contrary, use of the phrase ‘at least one of’, ‘one or more of’, ‘and/or’, variations thereof, or the like are open-ended expressions that are both conjunctive and disjunctive in operation for any and all possible combination of the associated listed items. For example, each of the expressions ‘at least one of X, Y and Z’, ‘at least one of X, Y or Z’, ‘one or more of X, Y and Z’, ‘one or more of X, Y or Z’ and ‘X, Y and/or Z’ can mean any of the following: 1) X, but not Y and not Z; 2) Y, but not X and not Z; 3) Z, but not X and not Y; 4) X and Y, but not Z; 5) X and Z, but not Y; 6) Y and Z, but not X; or 7) X, Y, and Z. 
     Additionally, unless expressly stated to the contrary, the terms ‘first’, ‘second’, ‘third’, etc., are intended to distinguish the particular nouns they modify (e.g., element, condition, node, module, activity, operation, etc.). Unless expressly stated to the contrary, the use of these terms is not intended to indicate any type of order, rank, importance, temporal sequence, or hierarchy of the modified noun. For example, ‘first X’ and ‘second X’ are intended to designate two ‘X’ elements that are not necessarily limited by any order, rank, importance, temporal sequence, or hierarchy of the two elements. Further as referred to herein, ‘at least one of’ and ‘one or more of can be represented using the’(s)′ nomenclature (e.g., one or more element(s)). 
     In one form, a system is provided. The system comprises: a first TDM card; a second TDM card that hosts an aggregation process configured to aggregate a first TDM based signal and a second TDM based signal into a combined TDM based signal; and a processor in communication with the first TDM card and the second TDM card, wherein the processor is configured to: obtain a packetized version of the first TDM based signal from the first TDM card; provide the packetized version of the first TDM based signal to the second TDM card; and prompt one or more packet cards to output packets based on the combined TDM based signal. 
     In one example, the second TDM card is configured to: obtain a working TDM based signal and a protection TDM based signal; select one of the working TDM based signal or the protection TDM based signal; and provide the one of the working TDM based signal or the protection TDM based signal to the aggregation process. 
     In one example, the first TDM card hosts a backup aggregation process configured to aggregate the first TDM based signal and the second TDM based signal into a backup combined TDM based signal. In a further example, the processor is further configured to: if the second TDM card fails, prompt the one or more packet cards to output further packets based on the backup combined TDM based signal. 
     In one example, the first TDM card is configured to: obtain the first TDM based signal via a first circuit in a circuit bundle that includes a second circuit configured to carry the second TDM based signal. In a further example, the second TDM card is configured to: obtain the second TDM based signal via the second circuit. In another further example, the system further comprises a third TDM card configured to: obtain the second TDM based signal via the second circuit. 
     In one example, the aggregation process is a virtual concatenation process. 
     In one example, the aggregation process is a multi-link aggregation process. 
     In one example, the second TDM card is configured to: generate a plurality of outgoing TDM based signals based on incoming packets obtained by the one or more packet cards; and provide, to the processor, at least one packetized version of at least one outgoing TDM based signal of the plurality of outgoing TDM based signals. 
     In one example, the processor is further configured to: obtain the at least one packetized version of the at least one outgoing TDM based signal from the second TDM card; and provide the at least one packetized version of the at least one outgoing TDM based signal to the first TDM card. 
     In another form, a method is provided. The method comprises: obtaining a packetized version of a first TDM based signal from a first TDM card; providing the packetized version of the first TDM based signal to a second TDM card that hosts an aggregation process configured to aggregate the first TDM based signal and a second TDM based signal into a combined TDM based signal; and prompting one or more packet cards to output packets based on the combined TDM based signal. 
     In one example, obtaining the packetized version of the first TDM based signal from the first TDM card includes: obtaining the packetized version of the first TDM based signal from a TDM card that hosts a backup aggregation process configured to aggregate the first TDM based signal and the second TDM based signal into a backup combined TDM based signal. 
     In one example, the method further comprises: if the second TDM card fails, prompting the one or more packet cards to output further packets based on the backup combined TDM based signal. 
     In one example, the method further comprises: obtaining, from the second TDM card, at least one packetized version of at least one outgoing TDM based signal generated based on incoming packets obtained by the one or more packet cards; and providing the at least one packetized version of the at least one outgoing TDM based signal to the first TDM card. 
     In another form, another method is provided. The method comprises: obtaining a packetized version of a first TDM based signal from a processor that obtained the packetized version of the first TDM based signal from a first TDM card; obtaining a second TDM based signal; aggregating, by an aggregation process, the first TDM based signal and the second TDM based signal into a combined TDM based signal; and prompting one or more packet cards to output packets based on the combined TDM based signal. 
     In one example, the method further comprises: obtaining a working TDM based signal and a protection TDM based signal; selecting one of the working TDM based signal or the protection TDM based signal; and providing the one of the working TDM based signal or the protection TDM based signal to the aggregation process. 
     In one example, the first TDM based signal is carried over a first circuit in a circuit bundle, the method further comprising: obtaining the second TDM based signal via a second circuit in the circuit bundle. 
     In one example, the aggregation process is a virtual concatenation process. 
     In one example, the aggregation process is a multi-link aggregation process. 
     One or more advantages described herein are not meant to suggest that any one of the embodiments described herein necessarily provides all of the described advantages or that all the embodiments of the present disclosure necessarily provide any one of the described advantages. Numerous other changes, substitutions, variations, alterations, and/or modifications may be ascertained to one skilled in the art and it is intended that the present disclosure encompass all such changes, substitutions, variations, alterations, and/or modifications as falling within the scope of the appended claims.