Abstract:
A system is disclosed for communicating with a plurality of network processors, one or more of the processors having a different operating environment, includes receiving an application programming interface (API) call from a user application, the API call including a call address identifying one or more of the network processors; and accessing a memory that identifies an appropriate form for the API call for each operating environment implemented by each network processor identified by the call address; and building one or more messages including the appropriate form for the API call for the operating environment of each of the network processors to receive any particular message.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     Under 35 USC §120, this application is a continuation application and claims the benefit of priority to U.S. patent application Ser. No. 10/387,847, filed Mar. 13, 2003 entitled “Method for Message Distribution to a Heterogeneous System”, all of which is incorporated herein by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates generally to messaging in distributed network processing systems and more specifically to message distribution in heterogeneous distributed network processing systems. 
     BACKGROUND OF THE INVENTION 
       FIG. 1  is a schematic block diagram of a distributed network processing system  100 . System  100  includes a control point (CP)  105  that is communicated to one or more network processors (NP)  110  by a switch  115 . CP  105  communicates to the NPs  110  by use of messages sent through switch  115 . Each message is marked with a destination address that is used by switch  115  to route the message. The destination address may be a unicast address or a multicast address. A unicast address identifies a single destination while a multicast address identifies one or more destinations. Switch  115  has a lookup table with an entry for each multicast address that indicates the members of the multicast set. 
     CP  105  includes a number of software components. There is a layer of software referred to as the Network Processor Application Services (NPAS) in CP  105  that provides services to User Applications to control NPs  110 . An application programming interface (API) exists between the NPAS and the user application. The user application defines programming calls and returns that are used to communicate with the NPAS. A management application  120  learns about each NP  115  through the NPAS. For example, the hardware version and the software version of each NP  115  is provided to management application  120  by the NPAS. A user is thereby enabled to know which level of hardware and software exists for each NP  110 . 
     The NPAS often is divided into multiple components, for example a first component  125 , a second component  130  and a controller  135 , with each of the components controlling a different NPAS function coordinated by control  135 . For example, component  125  may control an internet protocol (IP) function and component  130  may control a multi-protocol layer switch (MPLS) function. The components are often independent but are able to share common utilities within the NPAS. 
     The components take requests from the user application, process those requests, build messages based upon the requests and issue the messages to the appropriate NP or NPs. The appropriate NPs are indicated by the application through use of an address parameter in an API call. The address in the address parameter is often the same address used by the switch to direct the messages to the appropriate NP or NPs as it may be a unicast or a multicast address. 
       FIG. 2  is a schematic process flow diagram for a processing operation  200  of the NPAS shown in  FIG. 1 . Processing operation  200  begins with an API call  205  from an application. Processing operation  200  first checks the call inputs for validity at step  210 . After step  210 , processing operation  200  processes the call inputs at step  215 . This processing step  215  includes performing calculations or consulting internal data structures. Next at step  220 , processing operation  200  builds an appropriate message according to the processing results. The appropriate message is then sent to the appropriate NPs in step  225  and control is returned to the application. 
     In a homogeneous network environment in which all the NPs all have the same or equivalent versions the processing operation of  FIG. 2  operates satisfactorily. However, in a heterogeneous environment in which one or more NPs having a different or nonequivalent version are introduced into the network system a problem can arise. For purposes of this discussion, a different version of an NP is having a different hardware level or operating with a different software level as compared to a reference NP. An NP of a different version may require different messages or different message formats or have different functional capabilities as compared to the reference NP. For purposes of this discussion, an equivalent version for an NP as compared to a reference NP is one having a different version but the messages, the formats of these messages and the functional capabilities are the same for purposes of a particular API call or other relevant metric. 
     When the versions of the NPs are nonequivalent, the NPAS components need to perform different processing and send different messages and/or different message formats to various subsets of NPs as a result of a single API call. It is desirable to allow the processing overhead and burdens consequent to heterogeneous networks to be virtually transparent to any user application. What is needed is a solution that (a) reduces/minimizes an impact on current APIs, (b) reduces/minimizes an impact on NPAS components, (c) reduces/minimizes the number of messages sent through the switch, (d) the components should be independent of a coverage algorithm and (e) the NPAS components should not have to be aware of the many versions of hardware and/or software in the network system. Specifically, in (a), user applications may not be aware of the different versions of the NPs and it is preferable that a user application be able to operate in a heterogeneous system the same as it operates in a homogeneous network and to provide a single address (unicast or multicast) indicating the entire set of targeted NPs. In (b), it is not desirable to change the components in the NPAS when one or more NPs with a different version are introduced into a system. In (c), it is desirable to use multicast whenever possible to distribute the messages in order to minimize switch bandwidth usage. For (d), it is preferable that any algorithm used for determining the messaging subsets should be a common utility or function shared by all components. And (e), it would be advantageous that any additions of a new version NP not necessitate any change to any NPAS component. 
     Accordingly, what is needed is a method and system for providing transparent NP messaging in a heterogeneous network. The present invention addresses such a need. 
     SUMMARY OF THE INVENTION 
     A system and method is disclosed for communicating with a first network processor having a first operating environment and a second network processor having a second operating environment different from the first operating environment. The system includes a destination management service (DMS) including a memory, the memory registering (a) an application programming interface (API) call and recording an associated operating environment supporting the API call, (b) a messaging method appropriate for the API call in each operating environment; (c) a unicast address for each of the network processors and the operating environment for the network processor at each unicast address, and (d) a multicast address including the unicast addresses for the network processors; and a network processor application service, responsive to the API call from a user application identifying one or more network processors using a call address, the call address including the multicast address of one of the unicast addresses, for passing an identifier for the API call and the call address to the destination management service and for receiving a set of messaging methods for issuing the API call in appropriate form for the one or more operating environments implemented by the network processors addressed by the call address. The method for communicating with a plurality of network processors, one or more of the processors having a different operating environment, includes receiving an application programming interface (API) call from a user application, the API call including a call address identifying one or more of the network processors; and accessing a memory that identifies an appropriate form for the API call for each operating environment implemented by each network processor identified by the call address; and building one or more messages for the network processors identified by the call address, each of the one or more messages including the appropriate form for the API call for the operating environment of each of the network processors to receive any particular message. 
     The present invention permits transparent NP messaging in a heterogeneous network. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic block diagram of a distributed network processing system; 
         FIG. 2  is a schematic process flow diagram for a processing operation of the NPAS shown in  FIG. 1 ; 
         FIG. 3  is a flowchart of a preferred embodiment of the present invention for a message distribution process in a heterogeneous network; 
         FIG. 4  is a schematic block diagram of a distributed network processing system; 
         FIG. 5  is a schematic process flow diagram for a processing operation of an NPAS component shown in  FIG. 4  including DMS message sets with associated messaging methodologies. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 3  is a flowchart of a preferred embodiment of the present invention for a message distribution process  300  in a heterogeneous network. The preferred embodiment introduces a destination management service (DMS) into the NPAS in lieu of the previous control  135  shown in  FIG. 1 , as well as an architecture for components that are called messaging methods. In this new architecture, there are five entities including the user application, the NPAS component, a messaging entity, a transmission services and the new destination management service (DMS). The DMS tracks the various NP versions in a network system and determines a preferred set of messaging methods to be used for API call. The DMS interacts with the management component of the user application and the NPAS components in message distribution method  300  as shown in  FIG. 3 . 
     Process  300  performs a registration step  305  when the NPAS software is initialized. Each NPAS component registers with DMS. The NPAS component registers each API call within the component with the set of versions supported by the specific API call. Also indicated during the registration are the messaging methods required to process those versions. Versions are grouped as ranges so that all versions are not enumerated 
     After registration step  305 , message distribution process  300  performs another registration step  310 . Registration step  310  is performed during application initialization in which the user management function registers with the DMS all the unicast addresses in the system giving the version number associated with the NP at that address. 
     After registration step  310 , message distribution process  300  performs another registration step  315 . Registration step  315  is also performed during application initialization in which the user management application registers with the DMS all the multicast addresses in the system and provides the unicast addresses that make up the multicast set. 
     Thereafter message distribution process  300 , at API step  320 , includes an NPAS component receiving a request from an application. This request is an API call and includes a unicast or multicast address as a parameter. 
     At invocation step  325  the NPAS component receiving the API call invokes the DMS by passing it the API call (or an identifier to the API call) and the destination address from the API call parameter. 
     In response to invocation step  325 , message distribution process  300  executes DMS process  330 . DMS process  330  computes a preferred/optimal set of messages that must be sent to achieve the result requested in the original API. DMS process  330  also associates the proper messaging method for each message in the message set and returns the message set and methods to the NPAS component that invoked the DMS. It is believed that there are different ways of computing the message set and associating the methods with the messages, each may be preferable in a various scenario or specific embodiment. The present invention contemplates that each of these ways may be used in the preferred embodiment. DMS process  330  does consider the various versions of the NPs included within the destination address when computing the message set and methods to return. 
     After DMS process step  330 , message distribution process  300  processes the API call at step  335 . The NPAS component that receives the message set and associated messages processes the API call by using the messages of the message set using the messaging methods prescribed by the DMS and sends the messages to the addresses (also identified by the DMS). 
       FIG. 4  is a schematic block diagram of a distributed network processing system  400  according to the preferred embodiment. System  400  includes a control point (CP)  405  that is communicated to one or more network processors (NP)  410  by a switch  415 . CP  405  communicates to the NPs  410  by use of messages sent through switch  415 . Each message is marked with a destination address that is used by switch  415  to route the message. The destination address may be a unicast address or a multicast address. A unicast address identifies a single destination while a multicast address identifies one or more destinations. Switch  415  has a lookup table with an entry for each multicast address that indicates the members of the multicast set. 
     CP  405  includes a number of software components. There is a layer of software referred to as the Network Processor Application Services (NPAS) in CP  405  that provides services to User Applications to control NPs  415 . An application programming interface (API) exists between the NPAS and the user application that defines programming calls and returns used to communicate with the NPAS. A management application  420  learns about each NP  415  through the NPAS. For example, the hardware version and the software version of each NP  415  is provided to management application  420  by the NPAS. A user is thereby enabled to know which level of hardware and software exists for each NP  415 . 
     The NPAS often is divided into multiple components, for example a first component  425 , a second component  430  and a controller  435 , with each of the components controlling a different NPAS function coordinated by destination management service (DMS)  435 . For example, component  425  may control an internet protocol (IP) function and component  430  may control a multi-protocol layer switch (MPLS) function. The components are often independent but are able to share common utilities within the NPAS. 
     The components take requests from the user application, process those requests, build messages based upon the requests and issue the messages to the appropriate NP or NPs. The appropriate NPs are indicated by the application through use of an address parameter in an API call. The address in the address parameter is often the same address used by the switch to direct the messages to the appropriate NP or NPs as it may be a unicast or a multicast address. 
       FIG. 5  is a schematic process flow diagram for a processing operation  500  of an NPAS component including DMS message sets with associated messaging methodologies. Processing operation  500  begins with an API call  505  from an application (like step  205  shown in  FIG. 2 ). Processing operation  500  first checks the call inputs for validity at step  510 . After step  510 , processing operation  500  calls DMS at step  515 . DMS returns the set of processing methods and processing operation  500  iteratively uses the processing methods as indicated by the DMS to process the inputs (step  520 ), to build the appropriate message (step  525 ) and to send the appropriate message (step  530 ). After sending a message, processing operation  500  returns to perform step  520  through step  530  for each processing method until all processing methods have been executed by processing, building and sending all messages to all the addressed NPs. Once all processing methods are executed, processing operation  500  returns control to the application issuing the API call. 
     Although the present invention has been described in accordance with the embodiments shown, one of ordinary skill in the art will readily recognize that there could be variations to the embodiments and those variations would be within the spirit and scope of the present invention. Accordingly, many modifications may be made by one of ordinary skill in the art without departing from the spirit and scope of the appended claims.