Abstract:
A network apparatus for a network software service layer (NSSL) service bus. The network apparatus includes a memory storing executable instructions and a processor coupled to the memory, the processor executing the executable instructions, where the processor is configured to receive a service description comprising a named service and a network identifier identifying a network node associated with the named service, select a service description according to the named service, and transmit a named service request to the network node according to the service description selected.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    The present application is a continuation of U.S. patent application Ser. No. 14/806,154 filed Jul. 15, 2015 by Wu Chou, et al., and entitled “System and Apparatus of a Software-Service-Defined-Network (SSDN),” which is a continuation of U.S. patent application Ser. No. 13/829,076, now U.S. Pat. No. 9,106,515, filed Mar. 14, 2013 by Wu Chou, et al., and entitled “System and Apparatus of a Software-Service-Defined-Network (SSDN),” which claims priority to U.S. Provisional Patent Application No. 61/716,982 filed Oct. 22, 2012 by Wu Chou and entitled “System and Apparatus of a Software-Service-Defined-Network (SSDN)” and U.S. Provisional Patent Application No. 61/780,347 filed Mar. 13, 2013 by Wu Chou, et al. and entitled “System and Apparatus of a Software-Service-Defined-Network (SSDN),” all of which are incorporated herein by reference as if reproduced in their entireties. 
     
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0002]    Not applicable. 
       REFERENCE TO A MICROFICHE APPENDIX 
       [0003]    Not applicable. 
       BACKGROUND 
       [0004]    Software defined networking (SDN) is a next generation data network in which the control plane is separated from the data plane and implemented in a software application. This architecture allows network administrators to have programmable central control of network traffic without requiring physical access to the network&#39;s devices. Thus, SDN decouples network control (e.g. learning and forwarding decisions) from the data plane used to forward network traffic. Decoupling the control plane from the data plane of the network enables the network controller to efficiently control the network traffic through globally optimized traffic engineering and routing, which departs from locally optimized shortest path forwarding (SPF). SDN may also simplify network operations, or even have the capabilities to flatten the network with extended data routing vectors. The extended data routing vectors in SDN can cover network information from multiple Open Systems Interconnection (OSI) layers (e.g. Layer 2 (L2) and/or Layer (L3)) for intelligent routing purposes. A basic approach to achieve decoupling of the network control from the network topology and data plane is by applying globally aware and topology decoupled software control at the edges of the network. The assumption is that traditional topology-coupled bridging and routing may be re-used at the core of the network so that scalability, interoperability, high availability, and extensibility of the conventional networking protocols, such as Internet Protocol (IP) networks can still be maintained. 
       SUMMARY 
       [0005]    In one embodiment, the disclosure includes a network apparatus for a network software service layer (NSSL) service bus. The network apparatus includes a memory storing executable instructions and a processor coupled to the memory, the processor executing the executable instructions, where the processor is configured to receive a service description comprising a named service and a network identifier identifying a network node associated with the named service, select a service description according to the named service, and transmit a named service request to the network node according to the service description selected. 
         [0006]    In another embodiment, the disclosure includes a network controller including a local network information base (NIB) comprising data packet forwarding information, core logic coupled to the NIB, where the core logic comprises routing logic configured to consult the local NIB to determine a path for a data packet traversing through a network, and a transmitter configured to instruct one or more of a plurality of switches to transmit the data packet according to the path determined. 
         [0007]    In another embodiment, the disclosure includes a method of forwarding named service requests including storing a first service description in a service registration, where the first service description comprises a name of a service and a network node identifier of a network node that provides a named service, receiving a first service request, wherein the first service request comprises a requested named service, select the network node identifier associated with the requested named service in the service registration, and transmitting the first service request to the network node associated with the network node identifier selected. 
         [0008]    These and other features will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings and claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    For a more complete understanding of this disclosure, reference is now made to the following brief description, taken in connection with the accompanying drawings and detailed description, wherein like reference numerals represent like parts. 
           [0010]      FIG. 1A  is a schematic diagram of the current SDN paradigm. 
           [0011]      FIG. 1B  is a schematic diagram of an SSDN paradigm that includes the NSSL. 
           [0012]      FIG. 2  is a schematic diagram of an SSDN in accordance with a disclosed embodiment. 
           [0013]      FIG. 3  is a schematic diagram of system for coupling multiple SSDNs in accordance with a disclosed embodiment. 
           [0014]      FIG. 4  is a schematic diagram of a SSDN system in accordance with a disclosed embodiment. 
           [0015]      FIG. 5  illustrates an embodiment of a network unit in accordance with a disclosed embodiment. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    It should be understood at the outset that although an illustrative implementation of one or more embodiments are provided below, the disclosed systems and/or methods may be implemented using any number of techniques, whether currently known or in existence. The disclosure should in no way be limited to the illustrative implementations, drawings, and techniques illustrated below, including the exemplary designs and implementations illustrated and described herein, but may be modified within the scope of the appended claims along with their full scope of equivalents. 
         [0017]    SDN has become increasingly important for intelligent network engineering. SDN may become the infrastructure of the next generation data networking. SDN has the potential to make the network intelligent, open, globally optimized, and its routing dynamically adjustable to best fit the application needs.  FIG. 1A  is a schematic diagram of the current SDN paradigm  100  (e.g. prior art). The current SDN paradigm  100  may comprise an application layer  102 , a network control layer  104 , and a data transport layer  106 . The application layer  102  may comprise a plurality of applications  108  that may be utilized by the network control layer  104  and/or the data transport layer  106 . The network control layer  104  may determine paths for data packets to travel through a network. The data transport layer  106  may be the layer in which data flows from a source to a destination. The data transport layer may comprise a plurality of forwarding hardware (HW)  112  that may include switches and/or other network devices used for transporting data from a data center through a core network, a metro network, an access network, and the last mile to an end user. The network control layer  104  may comprise a plurality of controllers  110  (e.g., OpenFlow® (OF) controllers). The applications  108  in the data transport layer  106  may be coupled to the controllers  110  in the network control layer  104  via a plurality of “northbound” application programming interfaces (APIs). The controllers  110  may be coupled to the forwarding HW  112  via “southbound” APIs (e.g., the OF protocol). The controllers  110  may provide path forwarding instructions to the forwarding HW  112 . 
         [0018]    Unfortunately, huge technical challenges arise when implementing SDN for large scale development. In particular, SDN may result in an unprecedented large scale software based network system. As shown in  FIG. 1A , implementation of the application layer  102  and the network control layer  102  may result in a large, complex software based network system. The current SDN paradigm  100  provides a framework for “north-south” connections that provide communication between applications  108  and controllers  110  via the “northbound” API and between controllers  110  and forwarding hardware  112  via the “southbound” API. However,  FIG. 1A  does not illustrate a framework for “east-west” connections (e.g. an “eastbound” API and/or a “westbound” API) to manage the controllers  110  within the network control layer  102 . As a result, the current SDN paradigm  100  may not provide a connection framework that provides communication amongst the controllers  110 . Without a solid and sound software architectural foundation, SDN may be limited to some point solutions that may prevent its anticipated value from being fully realized. Hence, a solution is needed to efficiently implement SDN for a large scale development. 
         [0019]    Disclosed herein is a system, method, and apparatus for an SSDN. Further disclosed is an SSDN framework which may comprise an NSSL that may provide a service plane dedicated for network management and network control services. The NSSL may sit on top of the network layer and may expose network resources (e.g. the controller), the data forwarding switch, and other network functions, as services. NSSL may provide a service abstraction layer for SSDN and services deployed on NSSL may be addressed and consumed through service names and corresponding service interfaces to control and manage network resources and provide network services. NSSL may support advanced service computing features, such as late binding, mobility, failover, load balancing, in a tightly coupled network system. 
         [0020]    Also disclosed herein is a distributed service bus on the NSSL for service federation and management. The distributed service bus may provide seamless extension of the local SSDN network into a global SSDN network with the ability to support substantially optimized end-to-end service routing. Additionally, a Network Information Base (NIB) architecture is disclosed. The federated NIB architecture may dynamically combine and extend the NIB of local networks into a global NIB to support global network management and end-to-end optimized routing. 
         [0021]      FIG. 1B  is a schematic diagram of an SSDN paradigm  150  that includes the NSSL  154 . Similar to the SDN paradigm  100  discussed in  FIG. 1A , the SSDN paradigm  150  may comprise an application layer  102 , a network control layer  104 , and a data transport layer  106 . Moreover, the application layer  102  may comprise a plurality of applications  108 ; the network control layer  104  may comprise a plurality of controllers  110 , and the data transport layer  106  may comprise a plurality of forwarding HW  112 . In one embodiment, an NSSL  154  may sit on top of the network control layer  104  that may provide a service plane for the network control and management functionalities provided by the network control layer  104 . The NSSL  154  may provide a network service abstraction layer that supports the “east-west” network via service federation. In other words, the NSSL  154  may be configured to support the addition of controllers  110  and forwarding HW  112  within the network control layer  104  and the data transport layer  106 , respectively. The NSSL may comprise a plurality of service buses  152  that provide a distributed service access layer. The service buses  152  may support service mobility, migration, failover, and load balancing of the controllers  110 . Furthermore, the service buses  152  may support a variety of services, such as service computing operations of late binding, service discovery, service morphing, and service planning. The services may be implemented using hardware, software, or a combination of both.  FIG. 1B  also illustrates that the NSSL  154  may be implemented within the network control layer  104 . In another embodiment, the NSSL  154  may be a separate logical layer and exist between the application layer  102  and the network control layer  102 . 
         [0022]      FIG. 2  is a schematic diagram of an SSDN network  200  in accordance with a disclosed embodiment. As discussed above, the SSDN network  200  may support advanced service computing operations such as late binding, service discovery, service morphing, and service planning. The SSDN network  200  may provide a logical, centralized, and physically distributed global network view for networking to compute routing amongst a plurality of OF controllers  204 . The SSDN network  200  may provide a service composition framework through the NSSL service bus  216  that also support northbound applications (e.g. applications  108  in  FIG. 1B ). As shown in  FIG. 2 , the SSDN network  200  may comprise service bus utilities node  202 , a plurality of OF controllers  204 , network operating system (OS) services node  206 , an NSSL service bus  216 , a plurality of adapters  208 , a plurality of OF clients  210 , a switch data plane  212 , and a network  214 . The NSSL may comprise a variety of service components, such as the service bus utilities node  202 , the OF controllers  204 , OS services node  206 , adapters  208 , OF clients  210 , and NSSL service bus  216 . In one embodiment, SSDN network  200  may represent local SSDN networks  200  coupled together to form a global SSDN network. Local SSDN networks and global SSDN networks will be discussed in more detail in  FIG. 3 . 
         [0023]    The service bus utilities node  202  may comprise data storage and may store various service bus utilities, such as utilities facilitating communication and interaction between the OF controllers  204 . The service bus utilities node  202  may facilitate the transfer of various service bus utilities via the NSSL service bus  216 . The NSSL service bus  216  may be a distributed service access layer and a service plane for network control and management. The NSSL service bus  216  may provide a generic network service abstraction layer that may support “east-west” network expansion via service federation. Service federation may be the process through which the NSSL service bus  216  from different autonomous systems (AS) can share their services. The NSSL service bus  216  may be an architecture that may provide service registration, service discovery, message addressing, message routing, and other services for OF controllers  204 , OF clients  210 , and other service components coupled to the NSSL service bus  216 . In one embodiment, the NSSL service bus  216  may be a local NSSL service bus that may be coupled with other local NSSL service buses. In another embodiment, the NSSL service bus  216  may represent a global NSSL service bus  216  that comprises one or more local NSSL service buses that spans across multiple networks  214 . The NSSL service bus  216  may comprise a processor or logic unit and storage. 
         [0024]      FIG. 2  illustrates that OF controllers  204  and the OF clients  210  may be coupled to the NSSL service bus  216  via the adaptors  208 . The adaptors  208  may be configured to act as the service interface for the OF controllers  204  and OF clients  210 . By coupling the OF controllers  204  to the adaptors  208 , the NSSL service bus  216  may provide load balancing between the OF controllers  204 . The NSSL service bus  216  may also promote communication between the OF controllers  204  such that each OF controller&#39;s  204  NIB may comprise the same entries such that routing decisions made by either of the OF controllers  204  are the same. The NSSL service bus  216  may provide the ability to add additional OF controllers  204  as necessary in order to adequately manage and control SSDN network  200 . The NSSL service bus  216  may provide service composition, service discovery, service management, service fail over, and load balancing between the OF controllers  204 , and between the OF controllers  204  and the OF clients  210 . The NSSL service bus  216  may provide “east-west” network expansion capability through NSSL service bus federation and may provide a consistent service oriented framework. 
         [0025]    The OF controllers  204  may be configured to implement control plane functions and to control and manage OF clients  210 . Control plane functions may include route or path determination for data packets traversing the network  214 . More specifically, OF controllers  204  may be able to produce routing tables and/or flow tables that defines how to route data packets within network  214 . In  FIG. 2 , OF controller  204  may provide control services to both OF client_ 1   210  and OF client_ 2   210 . Similarly, OF controller 2   204  may also provide control services to both OF client_ 1   210  and OF client  2 _ 210 . The OF controller  204  may not perform data plane functions, such as forwarding data traffic to a selected destination within network  214 . The OF controllers  204  may deploy network resources to the NSSL as services via the corresponding adaptors  208 . In one embodiment, the services may be addressed by service names and may support service mobility, migration, failover, and load balancing. 
         [0026]    The OF clients  210  may be clients of the OF controllers  204 , such as OF switches. The OF clients  210  may provide data forwarding for network  214 . The OF client  210  may comprise a switch data plane  212  configured to route data through the network  214 . OF clients  210  may be any physical and/or virtual network device that receives and transmits data through network  214 . OF clients  210  may comprise switches, routers, bridges, or any other devices compatible with the southbound API services. For example, OF clients  210  may be configured according to the OpenFlow protocols as defined in Rev. 1.2 for the OpenFlow specification of the OpenFlow Organization, published December 2011, which is incorporated herein as if reproduced in its entirety. Furthermore, OF clients  210  may also include network devices that are compliant with other versions of the OpenFlow protocols (e.g. Rev. 1.0 and Rev. 1.1). In one embodiment, OF clients  210  may be incompatible with other versions of the OpenFlow protocols. For example, one OF client  210  may support the OpenFlow protocol version 1.0, but not later versions, while another OF client  210  may support the OpenFlow protocol version 1.2, but not earlier versions. 
         [0027]    The OS services node  206  may be a network OS that provides facilities for addressing the OF controllers  204 . The OS services node  206  may be independent of various programming languages. The OS services node  206  may be configured to manage network resources, including physical and virtual networks, for network applications. For example, the OS services node  206  may be implemented to manage data, users, groups, security, applications, and other networking functions. In one embodiment, the OS services node  206  may operate and perform functions in the OSI layer 3 within one or more network devices, such as routers, switches, and servers. 
         [0028]      FIG. 3  is a schematic diagram of another embodiment of an SSDN network  300 . As discussed above, by implementing NSSL, the SSDN network  300  may provide a network service abstraction layer that supports the “east-west” network via service federation.  FIG. 3  illustrates that SSDN network  300  may comprise coupling a plurality of local service buses  310 ,  324  and  325  for networks  302 ,  334 , and  335 , respectively. The local service buses  310 ,  324 , and  325  may be located within local SSDN networks. The coupling of the local service buses  310 ,  324 , and  325  may form a global service bus that spans across multiple networks (e.g. networks  302 ,  334  and  335 ). With a global service bus, the SSDN network  300  may combine routing services, control services, and network OS services (NOSS) component for networks  302 ,  334 , and  335  to form a global SSDN network  300 . In one embodiment, networks  302 ,  334 , and  335  may be different AS that share services via coupled local service buses  310 ,  324 , and  325  to form a global service bus. As shown in  FIG. 3 , local service bus  310  may be coupled to a global NIB  314 , while the local service buses  324  and  325  located within the SSDN sub-network  316  may share a global NIB  318 . Other embodiments of SSDN network  300  may have separate global NIBs  314  coupled to each local service buses  310 ,  324 , and  325  or share one global NIB  318  amongst the local service buses  310 ,  324 , and  325 . 
         [0029]      FIG. 3  illustrates that the local service bus  310  may be coupled to a service bus utilities node  312  and to a global NIB  314 . The service bus  310  may be configured to perform functions substantially similar to the NSSL service bus  216  discussed in  FIG. 2 . Moreover, the service bus utilities node  312  may be configured to perform functions substantially the similar to the service bus utilities node  202  discussed in  FIG. 2 . The global NIB  314  may maintain and provide necessary supporting information for resource utilization and traffic control amongst one or more networks. For instance, the global NIB  314  may provide multiple methods for the control logic to gain access to network nodes, index all the of the network nodes based on network node identifiers, track state information of network nodes, and network nodes features and capabilities. The global NIB  314  may store a graph of the forwarding HWs within a network topology instead of storing prefixes to destinations found in routing information bases (RIBs) or forwarding information bases (FIBs). Furthermore, the global NIB  314  may support logical elements (e.g. overlay tunnels) within a network. 
         [0030]    Local service bus  310  may also be coupled to NOSS component  304 , routing services (RS) component  306 , and controller services (CS) component  308 . The NOSS component  304  may be substantially similar to OS services node  206  discussed in  FIG. 2 . The RS component  306  may be coupled to network nodes within network  302 . The RS component  306  may implement algorithms to forward packets between network nodes (e.g. perform data forwarding plane functions). In one embodiment, the RS component  306  may forward data traffic as performed by an SDN/OpenFlow switch in the data forwarding plane. In one embodiment, network nodes within network  302  may be configured as plug-and-play network nodes. The CS component  308  may be a plurality of controllers coupled together through the service bus  310 . The CS component  308  may implement strategies to control the flow of data packets in network  302  as performed by an SDN controller in the control plane of SDN. 
         [0031]    As shown in  FIG. 3 , the SSDN network  300  may be divided into an SSDN sub-network  316 . The SSDN sub-network  316  may comprise one or more local SSDN networks. More specifically, the SSDN sub-network may comprise local service buses  324  and  325 , CS components  328  and  329 , RS components  330  and  331 , NOSS component  332  and  333 , service bus utilities node  320  and  322 , and global NIB  314 . Local service buses  324  and  325 , CS components  328  and  329 , RS components  330  and  331 , NOSS component  332  and  333 , and service bus utilities node  320  and  322 , may substantially similar to local service bus  310 , CS components  308 , RS components  306 , NOSS component  304 , and service bus utilities node  312 , which were discussed above. Global NIB  318  may perform functions substantially similar to the global NIB  314 , except that the global NIB  318  may be shared amongst two local service buses  324  and  325 . 
         [0032]    Within the SSDN sub-network  316 , local service bus  324  and  325  may be coupled to a global NIB  318 . Each local service bus  324  and  325  may be coupled to a service bus utilities node  320 ,  322 , respectively. Each local service bus  324  and  325  may comprise a cached NIB  326  and  327  that may be a store some or all of the information held within the global NIB  318 . The cached NIB  326  and  327  may be a local NIB used to monitor and provide network information for local SSDN networks. For example, NIB  326  may monitor and provide network information for network  334 , while NIB  327  may monitor and provide network information for network  335 . In one embodiment, the cached NIB  326  and  327  may store network information most frequently access from the global NIB  318 . Each local service bus  324  and  325  may be coupled to a respective CS component  328  and  329 , RS component  330  and  331  and NOSS component  332  and  333 . The RS component  330  and  331  may provide connections to network  334  and  335 , respectively. 
         [0033]      FIG. 4  is a schematic diagram of another embodiment of an SSDN network  400 . SSDN network  400  may comprise a plurality of controllers  404  coupled by an NSSL bus  402  and a plurality of networks  426  each comprising a plurality of OF switches  428 . The NSSL bus  402  may be substantially similar to a global service bus, as discussed in  FIG. 3 , except that the NSSL bus  402  may comprise a centralized NIB  406 . The centralized NIB  406  may maintain a master copy of the forwarding information that may be copied and used by each controller  404 . The centralized NIB  406  may be substantially similar to the global NIB  318  discussed in  FIG. 3 . 
         [0034]    Each controller  404  may comprise an OpenFlow Controller (OFC) API  408 , control logic  410 , a local NIB  422 , and a switch management component  424 . The local NIB  422  may cache frequently accessed information or otherwise store a copy of the centralized NIB  406 , which may be substantially similar to cached NIB  326  in  FIG. 3 . The OFC API may be coupled to the NSSL bus  402  and coordinate the actions of the controllers  404 . For example, the OFC API may be a Representational State Transfer (REST) API (e.g. Floodlight® REST API) that provides application interfaces for applications used to control networks  426 . The switch management component  424  may be configured to communicate with, control, and manage the OF switches  428  within networks  426 . The OF switches  428  may be any network component capable of receiving, transmitting, and forwarding data through networks  426 . 
         [0035]    The control logic  410  may comprise a routing component  412 , a device manager  414 , a core component  416 , a topology component  418 , and a link discovery component  420 . The routing component  412  may be configured to consult the local NIB  422  and to determine a path for a data packet traversing one or more of the networks  426  based on information retrieved from the local NIB  422 . The device manager  414  may be configured to manage the OF switches  428 , such as booting up the OF switches  428 , shutting down the OF switches, change routing tables in the OF switches, and update software on the OF switches. The topology component  418  may be configured to determine the topology of the network(s)  426 . The topology may comprise information about which OF switches  428  are connected to each other, the type of connections, the speed or data capacity of the connections, network elements coupled to the OF switches  428 . The link discovery module  420  may determine when a new link between switches  428  is created or a link between switches  428  is deleted or destroyed. The core component  416  may comprise one or more processors or application specific integrated circuits (ASICs) configured to implement the functionality of the various components  412 ,  414 ,  418 ,  420  in the control logic component  410 . In one embodiment, the core component is the platform on which the various components  412 ,  414 ,  418 ,  420  in the control logic component  410  may operate on. 
         [0036]    The NSSL bus  402  may provide distributed management of the networks  426 . The NSSL bus  402  may abstract the services provided by the controllers  404  and may direct a request for a particular service to an available controller  404  that is capable of providing the service. The centralized NIB  406  may dynamically combine and extend the local NIBs  422  of local networks  426  into a global NIB to support global network management and end-to-end optimized routing. In one embodiment, NSSL bus  402  may be a federated service bus (e.g. global service bus) coupled with local and distributed service components (e.g. OF controllers  404 ). For example, OF controllers  404  may register with the NSSL bus and expose their service descriptions. The service descriptions may defines message formats and other service information. A source OF controller  404  may send a message addressed to a destination OF controller  404  according to the destination OF controller&#39;s service description. The NSSL bus  402  may forward the message to the destination OF controller according to the service descriptions stored in the registration. 
         [0037]      FIG. 5  illustrates an embodiment of a network unit  500 , which may be any device that transports and processes data through the network that has sufficient processing power, memory resources, and network throughput capability to handle the necessary workload placed upon it. For instance, the network unit  500  may correspond to the NSSL service buses  216 ,  310 ,  324 ,  325 , and  402 , the OF controllers  204  and  404 , the OFC clients  210 , and/or the OF switches  428  described above. The network unit  500  may comprise one or more ingress ports or units  510  coupled to a receiver (Rx)  512  for receiving signals and frames/data from other network components. The network unit  500  may comprise a logic unit  520  to determine which network components to send data to. The logic unit  520  may be implemented using hardware, software, or both. The logic unit  520  may be implemented as one or more central processing units (CPUs) chips, or may be part of one or more ASICs. The network unit  500  may also comprise one or more egress ports or units  530  coupled to a transmitter (Tx)  532  for transmitting signals and frames/data to the other network components. The logic unit  520  may also implement or support the SSDN and NSSL methods and schemes described above. The components of the network unit  500  may be arranged as shown in  FIG. 5 . 
         [0038]    The logic unit  520  may be in communication with memory devices including secondary storage  504 , read only memory (ROM)  506 , and random access memory (RAM)  508 . The secondary storage  504  is typically comprised of one or more disk drives or tape drives and is used for non-volatile storage of data and as an overflow data storage device if RAM  508  is not large enough to hold all working data. Secondary storage  504  may be used to store programs that are loaded into RAM  508  when such programs are selected for execution. The ROM  506  is used to store instructions and perhaps data that are read during program execution. ROM  506  is a non-volatile memory device that typically has a small memory capacity relative to the larger memory capacity of secondary storage  504 . The RAM  508  is used to store volatile data and perhaps to store instructions. Access to both ROM  506  and RAM  508  is typically faster than to secondary storage  504 . 
         [0039]    At least one embodiment is disclosed and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of the disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of the disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, R 1 , and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=R 1 +k*(Ru−R 1 ), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 7 percent, . . . , 70 percent, 71 percent, 72 percent, . . . , 97 percent, 96 percent, 97 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed. The use of the term about means ±10% of the subsequent number, unless otherwise stated. Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present disclosure. The discussion of a reference in the disclosure is not an admission that it is prior art, especially any reference that has a publication date after the priority date of this application. The disclosure of all patents, patent applications, and publications cited in the disclosure are hereby incorporated by reference, to the extent that they provide exemplary, procedural, or other details supplementary to the disclosure. 
         [0040]    While several embodiments have been provided in the present disclosure, it should be understood that the disclosed systems and methods might be embodied in many other specific forms without departing from the spirit or scope of the present disclosure. The present examples are to be considered as illustrative and not restrictive, and the intention is not to be limited to the details given herein. For example, the various elements or components may be combined or integrated in another system or certain features may be omitted, or not implemented. 
         [0041]    In addition, techniques, systems, subsystems, and methods described and illustrated in the various embodiments as discrete or separate may be combined or integrated with other systems, modules, techniques, or methods without departing from the scope of the present disclosure. Other items shown or discussed as coupled or directly coupled or communicating with each other may be indirectly coupled or communicating through some interface, device, or intermediate component whether electrically, mechanically, or otherwise. Other examples of changes, substitutions, and alterations are ascertainable by one skilled in the art and could be made without departing from the spirit and scope disclosed herein.