Patent Publication Number: US-2020296033-A1

Title: Network services across non-contiguous subnets of a label switched network separated by a non-label switched network

Description:
TECHNICAL FIELD 
     The disclosed technology relates to providing network services across non-contiguous subnets of a label switched virtual private network. In particular, example embodiments relate to providing per tenant network services across enclaves of a Multiprotocol Label Switching (MPLS) network spanning an Internet Protocol (IP) network. 
     BACKGROUND 
     MPLS is a technology to direct digital data packets over computer networks based on path labels, rather than based on network addresses such as IP addresses. Each path label, also known as a “virtual private network” (VPN) label, identifies a path between network nodes, rather than only identifying the endpoints of the packet transmission. Routers of an MPLS network must be enabled to perform label switching to route and forward the packets. Such routers in the interior of an MPLS network are know as “label switch routers,” while such routers at the ingress and egress points of the MPLS network are known as “label edge routers.” Label edge routers discover and interface with non-MPLS networks outside the MPLS network using protocols such as Border Gateway Protocol (BGP). The outside networks can be provider networks, such as a national broadband provider IP networks, in which case the provider&#39;s routers are known as provider edge (PE) routers. The use of labels enables each MPLS router to maintain a separate routing and forwarding table instance, known as a virtual routing and forwarding (VRF) table or forwarding information base (FIB), for each of a plurality of tenants of the MPLS. 
     Generic Routing Encapsulation (GRE) is a point-to-point tunneling protocol in which two peer nodes form the endpoints of the tunnel. GRE is designed to encapsulate network-layer (L3) packets inside IP tunneling packets. Multi-point GRE (mGRE) is a similar protocol with a single endpoint at one side of the tunnel connected to multiple endpoints at the other side of the tunnel. An mGRE tunnel can provide a common link between branch offices that connect to the same VPN. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a block diagram depicting a communications and processing architecture to provide network services across non-contiguous subnets of a label switched virtual private network, in accordance with certain example embodiments. 
         FIG. 2  is a block flow diagram depicting a method to provide network services across non-contiguous subnets of a label switched virtual private network, in accordance with certain example embodiments. 
         FIG. 3  is a block flow diagram depicting a method to format a protocol data unit (PDU) of a label switching network to include a network service field specifying at least one network service to be applied to the PDU, in accordance with certain example embodiments. 
         FIG. 4  is a portion of a PDU used to provide network services across non-contiguous subnets of a label switched virtual private network, in accordance with certain example embodiments. 
         FIG. 5  is a block flow diagram depicting a method to format a PDU of a label switching network to include a network service field specifying at least one network service to be applied to the PDU, in accordance with certain example embodiments. 
         FIG. 6  is a portion of a PDU used to provide network services across non-contiguous subnets of a label switched virtual private network, in accordance with certain example embodiments. 
         FIG. 7  is a diagram depicting a computing machine and a module, in accordance with certain example embodiments. 
     
    
    
     DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS 
     Overview 
     Implementing an MPLS VPN over GRE or mGRE (MPLSoGRE) can overcome the requirement that all subnets participating in an MPLS network support MPLS. MPLSoGRE overcomes this requirement by allowing MPLS connectivity between non-contiguous MPLS subnets (hereinafter also referred to as MPLS “enclaves”) that are connected by non-MPLS networks, such as IP networks. MPLSoGRE allows MPLS label switched paths (LSPs) to use GRE tunnels to cross non-MPLS routing areas, autonomous systems, and Internet service providers (ISPs). For this reason, MPLSoGRE is being deployed to build large-scale private MPLS VPN networks comprising non-contiguous subnets over public IP transport. The MPLSoGRE functionality offers customers the scale and functions of MPLS VPN label forwarding networks, while leveraging the simplicity of public IP transport. The Internet Engineering Task Force (IETF) Request For Comment (RFC) 4797 describes an implementation strategy for such a network. 
     However, neither IETF RFC 4797, nor any other known publication, describes implementations for transporting network services information or policy information across non-contiguous MPLS subnets separated by one or more non-MPLS networks using MPLSoGRE. For example, an MPLS network operator might want to apply a policy that packets originating from a source node in a first enclave of the MPLS network pass through a cloud-based firewall network service in a second enclave of the MPLS network before being transmitted to a destination in a third enclave of the MPLS network. 
     Embodiments herein provide computer-implemented methods, systems, and computer program products for applying service chaining (and in some cases, the propagation of other metadata such as security data) to MPLSoGRE networks encompassing multiple enclaves separated by a non-MPLS network. 
     In some embodiments, in a first enclave of a label switching network, network computing device(s), such as a label edge router, format a protocol data unit (PDU) of the label switching network to include a network service field. The network service field specifies at least one network service to be applied to the PDU. The PDU specifies routing and forwarding information of the PDU for a path in the label switching network ending in an enclave of the label switching network other than the first enclave, and routing and forwarding information between enclaves in a non-label switching network. The network service field is positioned between the PDU data link layer and network layer of the non-label switching network. The label edge router communicates the formatted PDU from the first enclave, via the non-label switching network, to a second enclave of the label switching network in accordance with the routing and forwarding information between enclaves in the non-label switching network. 
     In the second enclave of the label switching network, a receiving router such as a label edge router of the second enclave, determines each network service specified to be applied to the PDU in the second enclave from the network service field of the communicated PDU. Computing devices of the second enclave apply each of the determined network services to the PDU. Computing devices of the second enclave, for example, a second enclave edge router, transmit the network serviced PDU in accordance with the routing and forwarding information of the PDU in the label switching network. 
     By using and relying on the methods and systems described herein, the technology disclosed herein provides for service chaining across non-contiguous subnets of a label switched computer network. As such, the technologies described herein may be employed to implement per-tenant and non-static service chains while retaining the benefits of a label-switched network and the benefits of inter-subnet transport using pervasive broadband non-label switched networks. The technology described herein can be used to leverage the availability of cloud network services (which are typically isolated in a cloud subnet) to transport data between label switched subnets. Hence, users of such technology avoid, among other things, static one-size-fits-all application of network services, the duplication of identical network services in each subnet, and cumbersome routing and forwarding schemes to link data with network services. 
     These and other aspects, objects, features, and advantages of the example embodiments will become apparent to those having ordinary skill in the art upon consideration of the following detailed description of illustrated example embodiments. 
     Turning now to the drawings, in which like numerals represent like (but not necessarily identical) elements throughout the figures, example embodiments are described in detail. 
     Example System Architectures 
     In example architectures for the technology, while each server, system, and device shown in the architecture is represented by one instance of the server, system, or device, multiple instances of each can be used. Further, while certain aspects of operation of the technology are presented in examples related to the figures to facilitate enablement of the claimed invention, additional features of the technology, also facilitating enablement of the claimed invention, are disclosed elsewhere herein. 
       FIG. 1  is a block diagram depicting a communications and processing architecture  100  to provide network services across non-contiguous subnets of a label switched virtual private network, in accordance with certain example embodiments. As depicted in  FIG. 1 , the architecture  100  includes label switching network enclaves  110 ,  120 , and  130 , along with service provider network  150  (a non-label switched network). In a continuing example, label switching enclaves  110  and  130  represent different physical subnets of a customer&#39;s non-contiguous MPLS network, while enclave  120  represents an MPLS enclave implemented by a service provider as a cloud service  160  for a customer. Each MPLS enclave  110 ,  120 , and  130  includes at least one customer edge device— 112 ,  122 , and  132 , respectively. Each customer edge device  112 ,  122 , and  132  (and by extension, each enclave  110 ,  120 , and  130 ) is associated with one or more VRF tables (for example,  118 ,  128 , and  138 , respectively) for allowing multiple concurrent instances of a routing table to exist within the device at the same time. In particular, each of enclaves  110 ,  120 , and  130  include a copy of VRF A  118 ,  128 , and  138 , respectively. The service provider network  150 , a non-label switched network, includes provider edge devices  152 ,  154 , and  156  to communicate with customer edge devices  112 ,  122 , and  132 , respectively. 
     In the continuing example, each customer edge device  112 ,  122 , and  132  is a label edge router implementing a version of the Border Gateway Protocol (BGP) to communicate with the corresponding service provider network  150  provider edge device (also implementing BGP). In some embodiments, other edge protocols, such as Exterior Gateway Protocol (EGP) can be used. Throughout this specification, “communicate” refers to the ability both to “transmit” and to “receive.” 
     Each of label switching enclaves  110 ,  120 , and  130 , along with service provider network  150 , includes one or more wired or wireless telecommunications systems including at least one label switched network such as an MPLS and generalized MPLS (which extends MPLS to manage further classes of interfaces and switching technologies other than packet interfaces and switching, such as time division multiplexing, layer-2 switching, wavelength switching and fiber-switching) by which network devices may exchange data in formats known as protocol data units (PDUs), packets, or frames. For example, the service provider network  150  may include one or more of a local area network (LAN), a wide area network (WAN), an intranet, an Internet, a storage area network (SAN), a personal area network (PAN), a metropolitan area network (MAN), a wireless local area network (WLAN), a virtual private network (VPN), a cellular or other mobile communication network, a BLUETOOTH® wireless technology connection, a near field communication (NFC) connection, any combination thereof, and any other appropriate architecture or system that facilitates the communication of signals, data, and/or messages. 
     Throughout the discussion of example embodiments, it should be understood that the terms “data” and “information” are used interchangeably herein to refer to text, images, audio, video, or any other form of information that can exist in a computer-based environment. 
     Each network device can include a communication subsystem capable of transmitting and receiving data over the network(s) it communicates with. For example, each network device can include a server, or a partition of a server, router virtual machine (VM) or container, a portion of a router, a desktop computer, a laptop computer, a tablet computer, a television with one or more processors embedded therein and/or coupled thereto, a smart phone, a handheld computer, a personal digital assistant (PDA), or any other wired or wireless processor-driven device. In some embodiments, a user associated with a device must install an application and/or make a feature selection to obtain the benefits of the technology described herein. 
     The network connections illustrated are examples and other approaches for establishing a communications link between the computers and devices can be used. Additionally, those having ordinary skill in the art and having the benefit of this disclosure will appreciate that the network devices illustrated in  FIG. 1  may have any of several other suitable computer system configurations, and may not include all the components described above. 
     In example embodiments, the network computing devices, and any other computing machines associated with the technology presented herein, may be any type of computing machine such as, but not limited to, those discussed in more detail with respect to  FIG. 7 . Furthermore, any functions, applications, or components associated with any of these computing machines, such as those described herein or any others (for example, scripts, web content, software, firmware, hardware, or modules) associated with the technology presented herein may by any of the components discussed in more detail with respect to  FIG. 7 . The computing machines discussed herein may communicate with one another, as well as with other computing machines or communication systems over one or more networks, such as network  110 ,  120 ,  130 , and  150 . Each network may include various types of data or communications network, including any of the network technology discussed with respect to  FIG. 7 . 
     EXAMPLE EMBODIMENTS 
     The example embodiments illustrated in the following figures are described hereinafter with respect to the components of the example operating environment and example architecture  100  described elsewhere herein. The example embodiments may also be practiced with other systems and in other environments. The operations described with respect to the example processes can be implemented as executable code stored on a computer or machine readable non-transitory tangible storage medium (e.g., floppy disk, hard disk, ROM, EEPROM, nonvolatile RAM, CD-ROM, etc.) that are completed based on execution of the code by a processor circuit implemented using one or more integrated circuits. The operations described herein also can be implemented as executable logic that is encoded in one or more non-transitory tangible media for execution (e.g., programmable logic arrays or devices, field programmable gate arrays, programmable array logic, application specific integrated circuits, etc.). 
     Referring to  FIG. 2 , and continuing to refer to  FIG. 1  for context, a block flow diagram depicting a method  200  to provide network services across non-contiguous subnets of a label switched VPN is shown, in accordance with certain example embodiments. In such a method  200 , in a first enclave of a label switching network (such as enclave  110 ), one or more computing devices (such as the CE router  112 ) formats a protocol data unit (PDU) of a label switching network to include a network service field specifying at least one network service to be applied to the PDU—Block  210 . The computing device(s) formats the PDU to specify routing and forwarding information of the PDU for a path in the label switching network ending in an enclave of the label switching network other than the first enclave. The computing device(s) format the PDU to specify routing and forwarding information between enclaves in a non-label switching network. The network service field is positioned between the PDU data link layer and network layer of the non-label switching network. 
     In a continuing example, an MPLS network operator applies a policy that packets originating from a source node (for example source node  114 ) in the first enclave  110  of the MPLS network pass through a cloud-based firewall  124  in the second enclave  120  of the MPLS network, before being transmitted to a destination (for example, destination  134 ) in the third enclave  130  of the MPLS network. In such a case, customer edge (CE) router  112  in enclave  110  formats the PDU to include the provision of cloud firewall services  124 . The CE router  112  also formats a label of the MPLS network to indicate a path to destination  134  in enclave  130  using a VPN label corresponding to the path from source  114 , through firewall  124 , and to destination  134 , using the instance of VRF A  118  associated with customer edge device  112 . In other examples, a network element of enclave  110  other than the CE router  112 , for example a security policy routine executing on source  114 , formats the PDU to specify that one or more services are to be applied to the PDU at certain points in the path. 
     Referring to  FIG. 3 , and continuing to refer to prior figures for context, a block flow diagram  300  depicting the operation of Block  210  is shown, in accordance with certain example embodiments (including the continuing example). In such methods, the second network is an Internet Protocol (IP) datagram network, and the network service field describes network service chaining using a network service header (NSH). NSH provides a service plane protocol for metadata exchange along a service path to specify services to be applied to a packet/frame/PDU. The services can include security functions (for example a firewall or an intrusion detection system), network acceleration and optimization, and server load balancing. Applying a sequence of services is known as “service chaining” or “service function chaining.” Implementations of NSH are described in IETF draft-ietf-sfc-nsh-05 (current version as of the filing date of the present application). 
     In the continuing example, as part of the Block  210 , the CE router  112  formats the PDU with a generic routing encapsulation (GRE) field of the service provider network  150  (an IP network) ahead of the network service header (NSH) field—Block  312 . Referring to  FIG. 4 , a portion of a PDU  400  used to provide network services across non-contiguous subnets of a label switched virtual private network is shown, in accordance with example embodiments, including the continuing example. In the continuing example, the CE router  112  formats the GRE field  410  in accordance with IETF RFC 2784, including formatting a GRE IP Header  412  with the service provider network  150  IP address of provider edge router  154 —the PE router providing access to the enclave hosting the service to be applied to the PDU. The CE router determines this address from the service information (a firewall of enclave  120  served by PE router  154  described below). CE router  112  learns of the IP address of provider edge router  154  via a border gateway protocol (BGP) operating between the service provider IP network  150  and each CE router of MPLS enclaves  110 ,  120 , and  130 . CE router  112  formats the GRE header  414  of the GRE field  410  to indicate that the encapsulated protocol is type 0x894F—corresponding to NSH. The CE router  112  places the GRE field  410  ahead of the NSH field  420  in the PDU. 
     In addition, as part of Block  210 , the CE router  112  formats an MPLS label of the label switching network (LSN) as a context header in the NSH field—Block  314 . In the continuing example, the CE router  112  formats the NSH field  420  per IETF draft-ietf-sfc-nsh-05 to specify a service path identifier (SPI), a service index (SI), a next protocol (NP), and at least two context headers (one context header for each service to be applied to the PDU, and one for the MPLS VPN path label for the path between the source  114  and the destination  134 ). In the continuing example shown in  FIG. 4 , the combination SPI/SI (10/255) corresponds to a transport layer of type GRE—as described above. The NP value shown in the body of field  420 , “MLS,” indicates that the context header  426 , and not the following fields  430  and  440 , will contain MPLS data in addition to containing service function chain (SFC) data. The NP value  422  (shown outside the body of field for clarity)  420  indicates that the fields  430  and  440  following the NSH field  420  are IPv4 protocol fields. The metadata type field  424  (0x1) (shown outside the body of field for clarity)  420  indicates that NSH  420  contains fixed length context headers. The first context header  426  carried by the NSH  420  is the MPLS VPN label for the path from the source  114  in the first enclave  110  to the destination  134  in the third enclave  130 . The second context header  428   a  identifies the firewall service  124  of enclave  120  as the service to be applied—it is from this data that the CE router  112  formatted the GRE label  410 . The NSH  420  can include additional fields for the application of additional services, for example context header N specifying service Y to be applied to the PDU after application of service  1  (the firewall  124 ). In the continuing example, only one service, the firewall  124 , is applied to the PDU. 
     Returning to  FIG. 2 , and continuing to refer to  FIG. 3  and  FIG. 4  for context, the one or more computing devices (such as the CE router  112 , PE router  152 , service provider network  150 , PE router  154 , and CE router  122 ) communicate the formatted PDU from the first enclave, via the non-label switching network, to a second enclave of the label switching network, in accordance with the routing and forwarding information between enclaves in the non-label switching network—Block  220 . In the continuing example, the CE router  112  transmits PDU  400  from enclave  110 , via PE router  152  and service provider network  150 , to the PE router  154  and CE router  122  in accordance with the routing and forwarding information contained in the GRE field  410 . PE routers  152  and  154  do not examine the NSH fields—hence the NSH and MPLS data is said to be “encapsulated” by the GRE data and is said to be communicated over the service provider network  150  through a GRE “tunnel” between PE router  152  and PE router  154 . The static BGP routing between the CE router  112  and PE router  152 , and then PE router  154  and the CE router  122 , ensures that the PDU is forwarded to the CE router  122 . Before forwarding the PDU to the CE router  122 , the PE router  154  strips the GRE data from the PDU, leaving the NSH  420  as the next field to be processed. The CE router  122  receives the PDU minus the GRE field applied by CE router  112 . 
     In the second enclave of the label switching network, the one or more computing devices (such as CE router  122 ), determines, from the network service field of the communicated PDU, each network service specified to be applied to the PDU—Block  230 . In the continuing example, in enclave  120 , CE router  122  determines, from NSH  420  internal next protocol (NP) value that the first context header  426  “MLS” will contain MPLS data in addition to containing service function chain (SFC) data. The first context header  426  carried by the NSH  420  is the MPLS VPN label  426  for the path from the source  114  to the destination  134 . The CE router  122  examines the second context header  428   a  to determine that the service to be applied to the PDU, before routing the PDU on the path indicated in the VPN label  426 , is the firewall service  124 . 
     The computing device(s) applies, in the second enclave, each of the determined network services to the PDU—Block  240 . In the continuing example, the CE router  122  of the second enclave  120  forwards the PDU, now stripped of the GRE header applied by the CE router  112  of the first enclave  110 , to the firewall  124  for network service processing. While the specific operation of the firewall  124  is outside the scope of this application, firewall  124  may use several strategies to control traffic flowing in the MPLS network, including analyzing PDU/packet contents for features such as paths and addresses, comparing packet meta-characteristics to profiles of allowed and prohibited packets. In some embodiments, firewall  124  is integrated in to CE router  112 . In some embodiments, the CE router forwards the PDU to a router closer to the firewall  124 . In the continuing example, the firewall examines the VPN label  126 , and determines that the PDU is allowed to pass to destination  134  from source  114  because the VPN label is on a whitelist of labels in the MPLS. Such information is propagated between network services by technologies known to those of skill in the relevant art, and is outside the scope of this application. In other embodiments, network services such as intrusion prevention, or load balancing are applied to the PDU based upon the service specified in the context field of the NSH  420 . For some such services, higher-level protocol data of the PDU, such as transport, session, presentation, and application data can be examined as part of applying the network service. 
     Upon completion of the network services specified to be applied in the receiving enclave, the PDU is transmitted in accordance with the label switched network routing and forwarding information of the PDU—Block  250 . In the continuing example, the Firewall  124  is an NSH-aware service, and upon completion of the service strips the firewall NSH context field  428   a  from the NSH field  420 , and returns the PDU to the CE router  122  of the second enclave  120  for determination of the next step in the communication of the PDU from the source  124  to the destination  134 . In other embodiments, the second enclave router nearest the firewall  124 , for example a label switch router of the enclave, strips the firewall NSH context field from the PDU and determines the path from the VPN label. In the continuing example, CE router  122  of the second enclave  120  examines the context headers of the NSH field  420 , and determines 1) that there are no more services to be applied to the PDU, and 2) that the VPN label indicates a path to a destination in enclave  130 . In some embodiments, a service audit trail is maintained by not stripping the context header of a completed service, but indicating in the context header that the service has been completed. For example, the service sets a “completed” flag in the corresponding context header. 
     In the continuing example, similar to Block  210 , CE router  122 , through examination of the VPN label in PDU  400  showing a path to destination  134  in enclave  130 , and through CE router&#39;s participation in the MPLS network and the IP network (through BGP), determines that the PDU must be routed to enclave  130  via a GRE tunnel from PE router  154  to PE router  156 . The CE router  122  of the second enclave  120 , then adds a new GRE label, in the same fashion as described above with regard to Blocks  210 ,  412 , and  414 , to the PDU for transport of the PDU from the second enclave  120  to the third enclave  130 . At the third enclave, CE router  132  received a PDU stripped of the newly added GRE field, examines the NSH field  420 . Since the NSH field  320  either contains no context fields requiring the application of network services, or contains an indication that network services have been applied to the PDU, forwards the PDU to its destination per the MPLS VPN label  426  contained in the NSH field  420 . 
     In other embodiments, MPLS VPN labels can be stacked. For example, a first enclave  110  router can apply a stack of MPLS VPN labels, such a VPN label  426 , to the NSH field  420  of a packet intended for a destination in a third enclave  130  via a second enclave  120  where services, such as firewall  124 , specified in the NSH  460  are to be applied. When the end of the path of the topmost label in the stack is reached, the node directing the PDU reads the next label in the stack and acts on the packet as described above. 
     Referring to  FIG. 5 , and continuing to refer to prior figures for context, a block flow diagram  500  depicting the operation of Block  210  is shown, in accordance with certain example embodiments (including a second example). In such methods, the second network is an Internet Protocol (IP) datagram network, and the network service field describes network service chaining using a network service header (NSH). 
     In the second example, as in the first example, an MPLS network operator applies a policy that packets originating from a source node (for example source node  114 ) in the first enclave  110  of the MPLS network pass through a cloud-based firewall  124  in the second enclave  120  of the MPLS network, before being transmitted to a destination (for example, destination  134 ) in the third enclave  130  of the MPLS network. In such a case, customer edge (CE) router  112  in enclave  110  formats the PDU to include the provision of cloud firewall services  124 . The CE router  112  also formats a label of the MPLS network to indicate a path to destination  134  in enclave  130  using a VPN label corresponding to the path from source  114 , through firewall  124 , and to destination  134 , using the instance of VRF A  118  associated with customer edge device  112 . 
     In the second example, as part of the Block  210 , the CE router  112  formats the PDU with a generic routing encapsulation (GRE) field of the service provider network  150  (an IP network) ahead of the network service header (NSH) field—Block  512 . Referring to  FIG. 6 , a portion of a PDU  600  used to provide network services across non-contiguous subnets of a label switched virtual private network is shown, in accordance with example embodiments, including the second example. In the second example, the CE router  112  formats the GRE field  610  in accordance with IETF RFC 4023, including formatting a GRE IP Header  612  with the service provider network  150  IP address of provider edge router  154 —the PE router providing access to the enclave hosting the service to be applied to the PDU. The CE router determines this address from the service information (a firewall of enclave  120  served by PE router  154  described below). CE router  112  learns of the IP address of provider edge router  154  via a border gateway protocol (BGP) operating between the service provider IP network  150  and each CE router of MPLS enclaves  110 ,  120 , and  130 . CE router  112  formats the GRE header  614  of the GRE field  410  to indicate that the encapsulated protocol is type 0x8847—corresponding to a multicast frame, the GRE field  410 , carrying the MPLS VPN label. CE router  112  formats an MPLS VPN label  616  of the label switching network within the GRE field  610  for the path between the source  114  and the destination  134 . The CE router  112  places the GRE field  410  ahead of the NSH field  420  in the PDU. 
     In addition, as part of Block  512 , the CE router  112  formats the NSH field  620  as described in connection with  FIG. 3  and  FIG. 4  above. The technology of the second example then proceeds with Blocks  220 - 250  as described above, except that the VPN label  616  in the second embodiment is examined by the receiving router, CE router  122  in the case of the second example, before determining the services specified in the NSH  620 , and then re-inserted by CE router  122  into the next GRE header for the non-MPLS segment of the path from PE router  154  to PE router  156 . 
     OTHER EXAMPLE EMBODIMENTS 
       FIG. 7  depicts a computing machine  2000  and a module  2050  in accordance with certain example embodiments. The computing machine  2000  may correspond to any of the various computers, servers, mobile devices, embedded systems, or computing systems presented herein. The module  2050  may comprise one or more hardware or software elements configured to facilitate the computing machine  2000  in performing the various methods and processing functions presented herein. The computing machine  2000  may include various internal or attached components, for example, a processor  2010 , system bus  2020 , system memory  2030 , storage media  2040 , input/output interface  2060 , and a network interface  2070  for communicating with a network  2080 . 
     The computing machine  2000  may be implemented as a conventional computer system, an embedded controller, a laptop, a server, a mobile device, a smartphone, a set-top box, a kiosk, a vehicular information system, one more processors associated with a television, a customized machine, any other hardware platform, or any combination or multiplicity thereof. The computing machine  2000  may be a distributed system configured to function using multiple computing machines interconnected via a data network or bus system. 
     The processor  2010  may be configured to execute code or instructions to perform the operations and functionality described herein, manage request flow and address mappings, and to perform calculations and generate commands. The processor  2010  may be configured to monitor and control the operation of the components in the computing machine  2000 . The processor  2010  may be a general purpose processor, a processor core, a multiprocessor, a reconfigurable processor, a microcontroller, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a graphics processing unit (GPU), a field programmable gate array (FPGA), a programmable logic device (PLD), a controller, a state machine, gated logic, discrete hardware components, any other processing unit, or any combination or multiplicity thereof. The processor  2010  may be a single processing unit, multiple processing units, a single processing core, multiple processing cores, special purpose processing cores, co-processors, or any combination thereof. According to certain embodiments, the processor  2010  along with other components of the computing machine  2000  may be a virtualized computing machine executing within one or more other computing machines. 
     The system memory  2030  may include non-volatile memories, for example, read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), flash memory, or any other device capable of storing program instructions or data with or without applied power. The system memory  2030  may also include volatile memories, for example, random access memory (RAM), static random access memory (SRAM), dynamic random access memory (DRAM), and synchronous dynamic random access memory (SDRAM). Other types of RAM also may be used to implement the system memory  2030 . The system memory  2030  may be implemented using a single memory module or multiple memory modules. While the system memory  2030  is depicted as being part of the computing machine  2000 , one skilled in the art will recognize that the system memory  2030  may be separate from the computing machine  2000  without departing from the scope of the subject technology. It should also be appreciated that the system memory  2030  may include, or operate in conjunction with, a non-volatile storage device, for example, the storage media  2040 . 
     The storage media  2040  may include a hard disk, a floppy disk, a compact disc read only memory (CD-ROM), a digital versatile disc (DVD), a Blu-ray disc, a magnetic tape, a flash memory, other non-volatile memory device, a solid state drive (SSD), any magnetic storage device, any optical storage device, any electrical storage device, any semiconductor storage device, any physical-based storage device, any other data storage device, or any combination or multiplicity thereof. The storage media  2040  may store one or more operating systems, application programs and program modules, for example, module  2050 , data, or any other information. The storage media  2040  may be part of, or connected to, the computing machine  2000 . The storage media  2040  may also be part of one or more other computing machines that are in communication with the computing machine  2000 , for example, servers, database servers, cloud storage, network attached storage, and so forth. 
     The module  2050  may comprise one or more hardware or software elements configured to facilitate the computing machine  2000  with performing the various methods and processing functions presented herein. The module  2050  may include one or more sequences of instructions stored as software or firmware in association with the system memory  2030 , the storage media  2040 , or both. The storage media  2040  may therefore represent examples of machine or computer readable media on which instructions or code may be stored for execution by the processor  2010 . Machine or computer readable media may generally refer to any medium or media used to provide instructions to the processor  2010 . Such machine or computer readable media associated with the module  2050  may comprise a computer software product. It should be appreciated that a computer software product comprising the module  2050  may also be associated with one or more processes or methods for delivering the module  2050  to the computing machine  2000  via the network  2080 , any signal-bearing medium, or any other communication or delivery technology. The module  2050  may also comprise hardware circuits or information for configuring hardware circuits, for example, microcode or configuration information for an FPGA or other PLD. 
     The input/output (I/O) interface  2060  may be configured to couple to one or more external devices, to receive data from the one or more external devices, and to send data to the one or more external devices. Such external devices along with the various internal devices may also be known as peripheral devices. The I/O interface  2060  may include both electrical and physical connections for operably coupling the various peripheral devices to the computing machine  2000  or the processor  2010 . The I/O interface  2060  may be configured to communicate data, addresses, and control signals between the peripheral devices, the computing machine  2000 , or the processor  2010 . The I/O interface  2060  may be configured to implement any standard interface, for example, small computer system interface (SCSI), serial-attached SCSI (SAS), fiber channel, peripheral component interconnect (PCI), PCI express (PCIe), serial bus, parallel bus, advanced technology attached (ATA), serial ATA (SATA), universal serial bus (USB), Thunderbolt, FireWire, various video buses, and the like. The I/O interface  2060  may be configured to implement only one interface or bus technology. Alternatively, the I/O interface  2060  may be configured to implement multiple interfaces or bus technologies. The I/O interface  2060  may be configured as part of, all of, or to operate in conjunction with, the system bus  2020 . The I/O interface  2060  may include one or more buffers for buffering transmissions between one or more external devices, internal devices, the computing machine  2000 , or the processor  2010 . 
     The I/O interface  2060  may couple the computing machine  2000  to various input devices including mice, touch-screens, scanners, electronic digitizers, sensors, receivers, touchpads, trackballs, cameras, microphones, keyboards, any other pointing devices, or any combinations thereof. The I/O interface  2060  may couple the computing machine  2000  to various output devices including video displays, speakers, printers, projectors, tactile feedback devices, automation control, robotic components, actuators, motors, fans, solenoids, valves, pumps, transmitters, signal emitters, lights, and so forth. 
     The computing machine  2000  may operate in a networked environment using logical connections through the network interface  2070  to one or more other systems or computing machines across the network  2080 . The network  2080  may include wide area networks (WAN), local area networks (LAN), intranets, the Internet, wireless access networks, wired networks, mobile networks, telephone networks, optical networks, or combinations thereof. The network  2080  may be packet switched, circuit switched, of any topology, and may use any communication protocol. Communication links within the network  2080  may involve various digital or analog communication media, for example, fiber optic cables, free-space optics, waveguides, electrical conductors, wireless links, antennas, radio-frequency communications, and so forth. 
     The processor  2010  may be connected to the other elements of the computing machine  2000  or the various peripherals discussed herein through the system bus  2020 . It should be appreciated that the system bus  2020  may be within the processor  2010 , outside the processor  2010 , or both. According to certain example embodiments, any of the processor  2010 , the other elements of the computing machine  2000 , or the various peripherals discussed herein may be integrated into a single device, for example, a system on chip (SOC), system on package (SOP), or ASIC device. 
     Embodiments may comprise a computer program that embodies the functions described and illustrated herein, wherein the computer program is implemented in a computer system that comprises instructions stored in a machine-readable medium and a processor that executes the instructions. However, it should be apparent that there could be many different ways of implementing embodiments in computer programming, and the embodiments should not be construed as limited to any one set of computer program instructions. Further, a skilled programmer would be able to write such a computer program to implement an embodiment of the disclosed embodiments based on the appended flow charts and associated description in the application text. Therefore, disclosure of a particular set of program code instructions is not considered necessary for an adequate understanding of how to make and use embodiments. Further, those skilled in the art will appreciate that one or more aspects of embodiments described herein may be performed by hardware, software, or a combination thereof, as may be embodied in one or more computing systems. Additionally, any reference to an act being performed by a computer should not be construed as being performed by a single computer as more than one computer may perform the act. 
     The example embodiments described herein can be used with computer hardware and software that perform the methods and processing functions described previously. The systems, methods, and procedures described herein can be embodied in a programmable computer, computer-executable software, or digital circuitry. The software can be stored on computer-readable media. For example, computer-readable media can include a floppy disk, RAM, ROM, hard disk, removable media, flash memory, memory stick, optical media, magneto-optical media, CD-ROM, etc. Digital circuitry can include integrated circuits, gate arrays, building block logic, field programmable gate arrays (FPGA), etc. 
     The example systems, methods, and acts described in the embodiments presented previously are illustrative, and, in alternative embodiments, certain acts can be performed in a different order, in parallel with one another, omitted entirely, and/or combined between different example embodiments, and/or certain additional acts can be performed, without departing from the scope and spirit of various embodiments. Accordingly, such alternative embodiments are included in the scope of the following claims, which are to be accorded the broadest interpretation so as to encompass such alternate embodiments. 
     Although specific embodiments have been described above in detail, the description is merely for purposes of illustration. It should be appreciated, therefore, that many aspects described above are not intended as required or essential elements unless explicitly stated otherwise. 
     Modifications of, and equivalent components or acts corresponding to, the disclosed aspects of the example embodiments, in addition to those described above, can be made by a person of ordinary skill in the art, having the benefit of the present disclosure, without departing from the spirit and scope of embodiments defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures.