Patent Document

TECHNICAL FIELD 
       [0001]    The present invention generally relates to network computing devices, and, more particularly, to devices that process data packets using single or multiple processing cores. 
       BACKGROUND 
       [0002]    As digital networks such as the Internet become increasingly commonplace, demand for network infrastructure devices such as bridges, switches, routers and gateways increases. With the advent and rapid adoption of wireless communications (e.g. so-called “Wi-Fi” communications based upon the IEEE 802.11 family of protocols), in particular, the need for wireless network infrastructure products is significant. Wireless switches, for example, are now commonly used to provide access to digital networks (such as the Internet or a corporate/campus network) via various wireless access points. Typically, a wireless switch remains in communication with one or more wireless access points via the network to facilitate wireless communications between the access point and digital network. One example of a wireless switch infrastructure based upon products available from SYMBOL TECHNOLOGIES INC. of San Jose, Calif. is shown in United States Patent Publication No. 2005/0058087A1. 
         [0003]    Like most conventional computers, network infrastructure devices commonly include a network interface, a processor, digital memory and associated software or firmware instructions that direct the transfer of data from a source to a destination. Because of the cost involved in designing customized hardware, particularly in the case of complex integrated circuitry, most network infrastructure devices have historically been built using commercially-available microprocessor chips, such as those produced and sold by INTEL CORP. of Santa Clara, Calif., FREESCALE SEMICONDUCTOR CORP. of Austin, Tex., AMD CORP. of Sunnyvale, Calif., INTERNATIONAL BUSINESS MACHINES of Armonk, N.Y., RAZA MICROELECTRONICS INC. of Cupertino, Calif. and others. 
         [0004]    In more recent years, technological advances in microprocessor and microcontroller circuitry have been significant. As an example, an emerging trend in microprocessor design is the so-called “multi-core” processor, which effectively combines the circuitry of two or more processors onto a common semiconductor die. Many conventional data processing systems that are based upon single processing cores can be limited in throughput in comparison to systems built upon multiple cores. By combining the power of multiple processing cores, however, the speed and efficiency of the computing chip is increased significantly. 
         [0005]    With the increasing demands constantly placed upon network infrastructure equipment, particularly in the wireless arena, it would be desirable to create network switches, particularly in the wireless and/or RFID environments, that take advantage of multi-core processing capabilities. Conventional software, however, is typically not written with such functionality in mind. As a result, there is a need for an architecture for constructing wireless, RFID and other networked switching devices upon a multi-processor platform. Moreover, there is a need for systems and techniques that provide such functionality. 
       BRIEF SUMMARY 
       [0006]    System flexibility and ease-of-design is greatly enhanced in a network wireless/RFID switching device by using a multicore abstraction layer (MCAL) to interface between a multicore hardware platform, a device operating system and the packet transfer functions of the system. Such an architecture may be particularly useful in constructing switches capable of switching wireless networking (e.g. IEEE 802.11 and/or IEEE 802.16), RFID or other network protocols, particularly using multi-core processors. A classification handler initially classifies the data packet. A plurality of protocol handlers each associated with a data protocol processes the data packet if the classification of the data packet matches the data protocol associated with the protocol handler, and one of several application handlers each associated with a user applications processes the data packet if the classification of the data packet matches the user application associated with the application handler. The MCAL is configured to send the data packet to the classification handler after the packet is initially received, and to subsequently direct the packet toward one of the protocol or application handlers in response to the classification of the data packet. MCAL further contains a set of the containers for handlers. Real application, protocol and classification handlers register with MCAL and are modules developed outside of the MCAL. 
     
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0007]    A more complete understanding of the present invention may be derived by referring to the detailed description and claims when considered in conjunction with the following figures, wherein like reference numbers refer to similar elements throughout the figures. 
           [0008]      FIG. 1  is a block diagram of an exemplary embodiment of an abstracted packet processing system; 
           [0009]      FIG. 2  is a block diagram of an exemplary embodiment of an abstracted packet processing system executing across multiple processing cores; 
           [0010]      FIG. 3  is a block diagram of a multi-core packet processing system; 
           [0011]      FIG. 4  is a block diagram of an exemplary memory allocation scheme; and 
           [0012]      FIG. 5  is a flowchart of an exemplary process for processing data packets; 
           [0013]      FIG. 6  is a flowchart of an exemplary classification process; 
           [0014]      FIG. 7  is a block diagram of an exemplary implementation of a multi-core wireless switch. 
       
    
    
     DETAILED DESCRIPTION 
       [0015]    The following detailed description is merely illustrative in nature and is not intended to limit the invention or the application and uses of the invention. Furthermore, there is no intention to be bound by any expressed or implied theory presented in the preceding technical field, background, brief summary or the following detailed description. 
         [0016]    The invention may be described herein in terms of functional and/or logical block components and various processing steps. It should be appreciated that such block components may be realized by any number of hardware, software, and/or firmware components configured to perform the specified functions. 
         [0017]    To enable portability between single core and multi-core systems, a multicore abstraction layer (MCAL) provides a framework that obscures the operating system executed by the system hardware to higher-level program code. Program code uses the MCAL to access system resources and for inter-process communication rather than accessing the operating system directly. By isolating system-specific code into the MCAL, higher level system code can be made more generic, thereby improving portability across single processor, multi-core processor, and/or multi-processor systems. Access to additional hardware (e.g. hardware co-processors) can also be provided through the abstraction layer, thereby further improving software flexibility and ease of design. 
         [0018]    Turning now to the drawing figures and with initial reference now to  FIG. 1 , an exemplary data processing system  100  suitably includes an abstracted operating system layer  102 , a classification handler  104 , a protocol handler  106 A-C for each communications protocol handled by system  100 , and an application handler  108 A-C for each control application executing on system  100 . Generally speaking, application handlers  108 A-C process data relating to control functions, whereas protocol handlers  106 A-C manage data simple data transactions. In the exemplary embodiment shown in  FIG. 1 , system  100  is shown as a wireless switch device capable of routing data packets formatted according to wireless protocols (e.g. IEEE 802.11 or the like) as well as radio frequency identification (RFID) protocols, in addition to any new and/or other protocols that may be desired. The use of wireless and RFID protocols is purely exemplary to illustrate that multiple protocols could be combined into a common system  100 . This feature is not necessary in all embodiments, and indeed many equivalent embodiments could be formulated to process any number of wired, wireless or other data communications protocols. 
         [0019]    The system  100  shown in  FIG. 1  could be implemented within any conventional single-processor general-purpose computing system that executes any suitable operating system. The LINUX operating system, for example, is freely available from a number of commercial and non-commercial sources, and is highly configurable to facilitate the features described herein. Equivalent embodiments could be built upon any version of the MacOS, SOLARIS, UNIX, WINDOWS or other operating systems. Each of these operating systems provide kernel space  101  as well as user space  103  as appropriate. In other embodiments, however, it is not necessary to separate kernel and user space. To the contrary, equivalent embodiments to those described above could be implemented within any sort of operating system framework, including those with “flat” memory architectures that do not differentiate between kernel and user space. In such embodiments, the MCAL  102  and the various handlers would all reside within the flat memory space. 
         [0020]    Kernel space  101  as shown in  FIG. 1  is any operating system portion capable of providing a multicore abstraction layer (MCAL)  102  to facilitate communication between hardware and software. Kernel  101  also provides software facilities that are provided to applications executing in user space  103  such as process abstractions, interprocess communication and system calls. Again, various equivalent embodiments may not differentiate between kernel space  101  and user space  103 , but may nevertheless provide the functionality of MCAL  102  within any convenient memory addressing structure. 
         [0021]    As noted above and below, MCAL  102  suitably contains any hardware-specific code for system  100 , and provides for communication between the various handlers  104 ,  106 A-C,  108 A-C. To that end, MCAL  102  typically includes a set of containers  110 A-C for representing various types of data handler modules  104 ,  106 ,  108  (described more fully below). Containers  110 A-C are any logical structures capable of facilitating inter-process data communications between modules. These communications structures may include, for example, message queues, shared memory, and/or the like. During system configuration and/or startup (or at any other suitable time), handler modules  104 ,  106 ,  108  register with MCAL  102 . MCAL  102  subsequently provides abstracted version of the system hardware and/or operating system resources to each handler  104 ,  106 ,  108  so that the various handlers need not be customized to the particular hardware present in any particular system. That is, handler modules  104 ,  106 ,  108  need not be customized or otherwise specially configured for multi-core or multi-processor operation, since such features are abstracted and provided within MCAL  102 . In various embodiments, then, the same code used to implement handlers  104 ,  106 ,  108  can be run in both single and multi-core environments, with MCAL  102  concealing the hardware specific features from the various handlers. MCAL  102  also initializes hardware components of system  102  as appropriate; such components may include networking interfaces, co-processors (e.g. special processors providing cryptography, compression or other features), and/or the like. MCAL also manages the downloading of handler code to the CPUs, as well as handler starting, stopping, monitoring, and other features. The various functions carried out by MCAL  102  may vary from embodiment to embodiment. 
         [0022]    Classification handler (CH)  104  is any hardware, software or other logic capable of recognizing data packets of various protocols and of assigning a classification to the data packet. This classification may identify the particular data type (e.g. wireless, TCP/IP, RFID, etc) based upon header information or other factors, and may further identify a suitable protocol handler  106 A-C or application handler  108 A-C for processing the data based upon data type, source, destination or any other criteria as appropriate. Classification module  104  therefore acts as a distribution engine, in a sense, that identifies suitable destinations for the various data packets. In various further embodiments, classification handler  104  may further distribute (or initiate distribution) of data packets to the proper handlers using message send constructs provided by MCAL  102 , as appropriate. Although  FIG. 1  shows only one classification handler  104 , alternate embodiments may include two or more classification handlers  104  as desired. Additional detail about an exemplary classification handler  104  is provided below in conjunction with  FIG. 6 . 
         [0023]    Protocol handlers (PH)  106 A-C are any software modules, structures or other logic capable of managing the data stack of one or more data communications protocols. An exemplary wireless handler  106 A, for example, could terminate Open Systems Interconnect (OSI) layer  2  and/or layer  3  encapsulation (using, e.g., the CAPWAP, WISP or similar protocol) for packets received from wireless access points, and may also terminate 802.11, 802.16, RFID or any other wireless or wired protocols, including any security protocols, to extract data packets that could be transferred on a local area or other wired network. Conversely, wireless handler  106 A could initiate encapsulation of data received on the wired network for transmittal to a wireless client via a remote access point, as appropriate. In other embodiments, the send and receive processes could be split into separate protocol handlers  106 , as desired. 
         [0024]    Application handlers (AH)  108 A-C are any software programs, applets, modules or other logic capable of hosting any type of application or control path features of one or more protocols. In the example shown in  FIG. 1 , wireless application handler  108 A processes control functions (e.g. 802.11 signaling and management functions (authentication, association etc), 802.1× authentication, administrative functions, logging, and the like) associated with the transfer of wireless (e.g. 802.11) data. Multiple application handlers  108  could be provided for separate control features, if desired. 
         [0025]    In operation, then, data packets arriving at a network interface or other source are initially provided to classification handler  104 , which assigns a classification to the packet and optionally forwards the packet to the appropriate protocol handler  106 A-C and/or application handler  108 A-C according to the classification. Inter-process communication and any interfacing to system hardware is provided using MCAL  102 . 
         [0026]    Turning now to  FIG. 2 , an exemplary implementation of a multi-core data processing system  200  suitably includes a control processor  201  in addition to one or more data handling processors  203 A-C. Control processor  201  typically executes the base operating system (e.g. LINUX or the like), whereas the data handling processors  203 A-C execute the various handler logic (e.g. classification handler  104 , protocol handler  106 , application handler  108  shown in  FIG. 1 ). By dividing the data handling function from the operating system function, the overall throughput of system  200  can be markedly improved in many embodiments. The term “processor” as used in this context can refer to a physical processor, to a processing core of a multi-core processing chip, or to a so-called “virtual machine” running within a processor or processing core. That is, the MCAL  102  is created to adapt system  200  to available hardware so that the individual handler modules  104 ,  106 ,  108  need not be individually tailored to the particular hardware environment used to implement system  200 . Similarly, any number of control and/or data handling processors  201 ,  203  could be used in a wide array of alternate embodiments. 
         [0027]    Data handler modules  104 / 106 / 108  may be assigned to the various processors  201 ,  204  in any manner. In various embodiments, handler modules  104 / 106 / 108  are statically assigned to available hardware by pre-configuring the modules loaded at system startup or reset. Alternatively, modules  104 / 106 / 108  can be dynamically assigned to reduce any performance bottlenecks that may arise during operation. In such embodiments, MCAL  102  (or another portion of system  100 ) suitably assigns modules to available processing resources based upon available load. Load may be determined, for example, through periodic or aperiodic polling of the various processing cores  203 , through observation of data throughput rates, and/or through any other manner. In various embodiments, MCAL  102  periodically polls each processing core to determine a then-current loading value, and then re-assigns over or under-utilized handler modules  104 / 106 / 108  in real time based upon the results of the polling. As noted above, MCAL  202  suitably includes any number of container structures  110 A-C for facilitating inter-process communications between each of the various handler modules executing on the various and/or to otherwise abstract the multi-core hardware structure from particular software modules  104 ,  106 ,  108  ( FIG. 1 ) as appropriate. 
         [0028]    With reference now to  FIG. 3 , an exemplary data processing system  300  is shown in increasing detail. This system  300  suitably includes separate processors  201 ,  203 A-C for control and data handling functions (respectively), with each processor  201 ,  203  executing any number of concurrent threads  302 A-D as shown. System  300  also includes a digital memory  305  such as any sort of RAM, ROM or FLASH memory for storing data and instructions, in addition to any available mass storage device such as an sort of magnetic or optical storage medium. An optional coprocessor  304  may be provided to perform specialized tasks such as cryptographic functions, compression, authentication and/or the like. The various components of system  300  intercommunicate with each other via any sort of logical or physical bus  306  as appropriate. 
         [0029]    In various embodiments, each control and data handling processor contains several “virtual” or logical machines  302 A-D that are each capable of acting as a separate processor. In such cases, a software image containing data handlers  104 / 106 / 108  is executed within each active logical machine  302 A-D as a separate thread that can be processed by data handler. Typically, each processing core  201 ,  203  includes its own “level  1 ” data and instruction cache that is available only to threads operating on that core. Memory  305 , however, typically represents a memory subsystem that is shared between each of the processing cores  201 ,  203  found on a common chip. Memory  305  may also provide “level  2 ” cache that is readily accessible to all of the threads  302 A-D running on each of the various processing cores  201 ,  203 . 
         [0030]    System  300  suitably includes one or more network interface ports  310 A-D that receive data packets from a digital network via a network interface. The network interface may be any sort of network interface card (NIC) or the like, and various systems  300  may have several physical and/or logical interface ports  310 A-D to accommodate significant traffic loads. As noted above, data handlers may be assigned to the various processing cores  203 A-C and the various processing threads  302 A-D using any sort of static or dynamic process. 
         [0031]    In many embodiments, a packet distribution engine  308  is provided to initially distribute packets received via the network interface ports  310 A-D to the appropriate classification handler  104 . Packet distribution engine  308  is any hardware, software or other logic capable of initially providing access to data packets received from ports  310 A-D. In various embodiments, packet distribution engine  308  may be implemented in an application specific integrated circuit (ASIC) for increased speed, for example, or the functionality could be readily combined with one or more classification handlers  104  using software or firmware logic. In either case, data packets arriving from network ports  310 A-D are directed toward an appropriate classification handler  104  executing on one of the data handler processors  203 A-C. This direction may take place in any manner; in various embodiments, each network port  310 A-D has an associated classification handler  104  executing as a separate thread  302  on one of the data handling processors  203 A-C. Alternatively, packets arriving at any port  310 A-D are initially directed toward a common classification handler  104 . 
         [0032]    Classification, protocol and application handlers  104 / 106 / 108  are contained within a software image that is executed on each of the available data handling processors  203 A-C, and operating system software is executed on the control plane  201 . That is, the various data handlers  104 / 106 / 108  can be combined into a common software image so that each thread  302 A-D on each processor  203 A-C executes common software to provide the various data handling functions. This feature is optional, however, and not necessarily found in all embodiments. 
         [0033]    As noted above, classification handlers  104  suitably classify and dispatch incoming data packets to an appropriate destination handler, such as a operating system thread on control processor  301  or a protocol or application handler on data handling processors  303 A-C. Each protocol handler  106  typically runs a thread of a specific protocol supported by system  300  (e.g. 802.11 wireless, RFID, 802.16, any other wireless protocol, and/or any security protocols such as IPSec, TCP/IP or the like), and each application handler  108  runs an appropriate processing application to provide a feature such as location tracking, RFID identification, secure sockets layer (SSL) encryption and/or the like. As described above, protocol handlers  106  typically provide processing of actual data, whereas application handlers  108  typically provide control-type functionality. As noted above, MCAL  102  ( FIGS. 1-2 ) assigns the various processors  201 ,  203  and threads  302  to each data handler  104 / 106 / 108  on a static, dynamic or other basis as appropriate. In single processor embodiments, MCAL  102  typically maps each handler to the same processor  201  that is running the operating system. MCAL  102  may physically reside within either processor  201 , or any of processors  203 A-C. Alternatively, the various functions performed by the MCAL  102  can be split across the various processors  201 ,  203  as appropriate. 
         [0034]    In various further embodiments, a co-processor module  304  may also be provided. This module may be implemented with custom hardware, for example, to provide a particular computationally-intense feature such as cryptographic functions, data compression and/or the like. Co-processor module  304  may be addressed using the message send and receive capabilities of the MCAL  102  just as the various threads  302 A-D executing on the multiple processing cores  301 ,  303 A-C. 
         [0035]    Referring to  FIG. 4 , an exemplary memory and addressing scheme  600  includes a pool  405  of memory space suitable for storing received data packets  409 A-E, along with a packet descriptor  407  that contains a brief summary of relevant information about the data packet itself. This descriptor  407  may be created, for example, by a classification handler  104  ( FIGS. 1-4 ), and includes such information as packet type  404 , a pointer  406  to a source address, a pointer  408  to a destination address, a pointer  410  to the beginning of the packet, a copy  412  of any relevant message headers, and any relevant description  414  of the packet payload (e.g. the length of the payload in bytes). Various descriptors  407  may contain alternate information as appropriate. Source and destination address pointers  406 ,  408  may be obtained in any manner; in various embodiments, this information is obtained from a lookup table  402  or other appropriate data structure maintained within system memory  305 . This information may be looked up in one handler (e.g. the classification handler), for example, and pointers to the relevant addresses may be maintained in the packet descriptor  407  to reduce or eliminate the need for subsequent lookups, thereby improving processing speed. With momentary reference again to  FIG. 3 , the data packet  409 A-E and its associated data descriptor  407  can be maintained within system memory  305 , where this information is readily accessible to each thread  302 A-D executing on each processing core  301 ,  303 A-C. 
         [0036]    Turning now to  FIG. 5 , an exemplary generic process  500  for routing a data packet (e.g. packets  407 A-E) through a data processing system (e.g. systems  100 ,  200 ,  300  described above) suitably includes the broad steps of receiving the data packet (step  502 ), determining an appropriate recipient handler (steps  506 - 510 ), and then “sending” the message to the destination handler (step  514 ). Process  500  is intended to illustrate the logical tasks performed by the data processing system; it is not intended as a literal software implementation. A practical implementation may arrange the various steps shown in  FIG. 5  in any order, and/or may supplement or group the steps differently as appropriate. Nevertheless, process  500  does represent a logical technique for routing data packets that could be implemented using any type of digital computing hardware, and that could be stored in any type of digital storage medium, including any sort of RAM, ROM, FLASH memory, magnetic media, optical media and/or the like. The process outlined in  FIG. 5  may be logically incorporated into the MCAL  102  best seen in  FIGS. 1-2 , for example, or may be otherwise implemented as appropriate. 
         [0037]    As data packets are received at the message queue (step  502 ), the MCAL  102  first determines the appropriate handler to process the received message (step  506 ). In the event that the data packet is newly received from the network port (e.g. ports  310 A-C in  FIG. 3 ), then the handler is typically a classification handler  104  as described above (step  508 ). Otherwise, the destination handler can be determined from examination of the packet descriptor (see discussion of  FIG. 4  above) contained within memory  305  ( FIG. 3 ). 
         [0038]    In various embodiments that maintain a common code image running in all threads, the classification handler  104 , protocol handlers  106  and application handlers  108  are optionally invoked within the packet routing function  300  (step  512 ). In such embodiments, a switch-type data structure or the like identifies the destination as the classification handler  104 , the appropriate protocol hander  106 A-C for the particular protocol carried by the data packet, or the application handler  108 A-C for the application type identified by the data packet. This feature is not required in all embodiments; to the contrary, step  512  may be omitted entirely in alternate but equivalent embodiments in which a common code image is not provided. 
         [0039]    Upon determination of the appropriate destination for the data packet, the message is directed or “sent” (step  514 ) using any appropriate technique. The term “sent” is used colloquially here because the entire data packet need not be transported to the receiving module. To the contrary, a pointer to the packet or packet descriptor (see below) in memory  305  could be transmitted to the receiving module without transporting the packet itself, or any other indicia or pointer to the appropriate data could be equivalently provided. 
         [0040]    Process  500  may be repeated as appropriate (step  516 ). In various embodiments, the “packet receive” feature is a blocking function provided by the MCAL  102  that holds execution of process  500  at step  502  (or another appropriate point) until a message is received in the message queue. As noted above, message queuing, as well as message send and receive features are typically provided within the MCAL  102  to make use of operating system and hardware-specific features. 
         [0041]    Turning now to  FIG. 6 , an exemplary process  600  for classifying data packets (e.g. packets  407 A-E in  FIG. 4 ) suitably includes the broad steps of classifying the incoming packets (steps  602 - 618 ) and performing pre-processing by formatting and storing the packet as appropriate (step  622 ) to facilitate direction toward a particular protocol or application handler. Like process  500  above, process  600  is intended to illustrate various features carried out by an exemplary process, and is not intended as a literal software implementation. Nevertheless, process  600  may be stored in any digital storage media (such as those described above) and may be executed on any processing module  201 ,  203  as appropriate. Moreover, the exemplary process  600  shown in  FIG. 6  illustrates multiple protocol implementation using the examples of wireless communication and RFID communication. Alternate embodiments could be built to support any number (e.g. one or more) protocols, without regard to whether the protocols are wired, wireless or otherwise. 
         [0042]    Process  600  generally identifies packets as wireless (steps  602 ,  604 ,  606 ), RFID (steps  608 ,  610 ), application (steps  612 ,  614 ) or management/control (steps  616 ,  618 ,  620 ). These determinations are made based upon any appropriate factors, such as header information contained within the data packet itself, the source of the packet, the nature of the packet (e.g. packet size), and/or any other relevant factors. As the type of packet is identified, a classification is assigned to the packet (steps  606 ,  610 ,  614 ,  618 ,  620 ) to direct the packet toward its appropriate destination processing module. In the example of  FIG. 6 , packets that do not meet pre-determined classification criteria are sent to the operating system for further processing by default; alternate embodiments may discard the packet, forward the packet to another classification module  104 , or take any other default action desired. 
         [0043]    Classification process  600  also involves performing preprocessing (step  622 ) on the data packet. Pre-processing may involve creating and/or populating the data descriptor  407  for the packet described in conjunction with  FIG. 4  above, and/or taking other steps as appropriate. In various embodiments, classification process  600  may include performing lookups to tables  402  ( FIG. 4 ) to identify source, destination or other information about the packet. Although  FIG. 6  shows step  622  as occurring only after the packet has been classified, in practice some or all of the data formatting, storing and/or gathering may equivalently take place prior to or concurrent with the classification process. 
         [0044]    With final reference now to  FIG. 7 , an exemplary embodiment of a wireless switch  700  that is capable of directing wireless traffic (e.g. IEEE 802.11 and/or 802.16 traffic) and RFID traffic is shown. Again, the combination of wireless and RFID protocols is intended merely as an example; in practice, device  700  may be any type of bridge, switch, router, gateway or the like capable of processing any number of protocols, and any type of wired or wireless protocols using any type of hardware and software resources. Further, alternate embodiments of the switch  700  could be readily formulated in many different ways; the particular data processing handlers  104 / 106 / 108 , for example, could reside within any processing threads  302  executed by any of the data handling processors  203 . 
         [0045]    Wireless switch  700  suitably includes multiple processing cores  201  and  203 A-C, with core  201  running an operating system (e.g. LINUX) in threads  302 C-D. Application handlers  108 A-B providing control path handling for wireless access and RFID protocols, respectively, are shown executing within threads  302 A-B of processing core  201 , although alternate embodiments may move the application handlers  108 A-B to available threads  302  on data handling cores  303 A-C as appropriate. Threads  302 A-B of processor  203 A are shown assigned to classification handlers  104 A-B, and threads  302 C-D of processor  203 A are shown assigned to protocol handlers  106 A associated with RFID protocols. The remaining threads  302 A-D on processing cores  303 C-D are shown assigned to protocol handlers  106  for wireless communications, with each thread having assigned wireless access points (APs). Thread  302 A of processor core  203 B, for example, is assigned to process wireless data emanating from access points  1  and  9 , whereas thread  302 B of core  203 B processes wireless data emanating from APs  2  and  10 . Access points need not be assigned to particular protocol handlers  106  in this manner, but doing so may aid in load balancing, troubleshooting, logging and other functions. 
         [0046]    In operation, then data packets arrive at wireless switch  700  via one or more network interface ports  310 A-D from a local area or other digital network. These packets are initially directed toward a classification handler (e.g. handlers  104 A-B on processing core  203 A) by packet distribution engine  308 . Alternatively, distribution engine  308  provides a portion of the classification function by storing the received packet in memory  305 , and providing a pointer to the relevant packet to classification handler  104 A or  104 B. The classification handler  104 , in turn, classifies the data packet as wireless, RFID, control and/or the like, and selects and appropriate protocol handler  106  or application handler  108  as appropriate. The relevant handler subsequently receives a pointer or other notification of the packet&#39;s location in memory  105 , and processes the packet normally. Optionally, MCAL  102  monitors the loads on each processing core during operation, and re-assigns one or more handlers to keep loads on the various processing cores relatively balanced during operation. 
         [0047]    As noted at the outset, the MCAL framework allows for efficient code design, since code can be designed to work within the framework, rather than being created for particular hardware platforms. Moreover, legacy code can be made to work with emerging hardware platforms by simply modifying the code to work within the abstraction constructs rather than addressing the hardware directly. Other embodiments may provide other benefits as well. 
         [0048]    While at least one example embodiment has been presented in the foregoing detailed description, it should be appreciated that a vast number of equivalents exist. It should also be appreciated that the example embodiment or embodiments described herein are not intended to limit the scope, applicability, or configuration of the invention in any way. Rather, the foregoing detailed description will provide those skilled in the art with a convenient road map for implementing the described embodiment or embodiments. It should be understood that various changes can be made in the function and arrangement of elements without departing from the scope of the invention as set forth in the appended claims and the legal equivalents thereof.

Technology Category: 5