Abstract:
Systems and techniques are provided for Topology-Static (TS) architecture within a computer system, and more particularly to the management of a Topology-Static architecture incorporating a storage area network (SAN). A SAN management system for monitoring and controlling zone integrity of a SAN. The SAN management system includes a monitoring module coupled to a SAN zone that includes at least one loop and optionally at least one fabric switch. When the status of the SAN zone changes, the monitoring manager sends an intimating signal to a zone manager. The zone manager determines whether such intimating signal is associated with a change pertaining to a node of any TS-Zone in “I” mode. If so, the zone manger sends a request to a switch manager for execution. After the execution, the zone manager further updates information stored in an internal storage relating to the change event.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to Topology-Static (TS) architecture within a computer system, and more particularly to the management of a Topology-Static architecture. 
     BACKGROUND OF THE INVENTION 
     A storage area network (SAN) has significantly changed the manner of storing and accessing data from a conventional local database, such as file servers, to a remote network of its own. With the increasing amount of data to be stored, the local database associated with a computer is no longer capable of storing all the data. The SAN has solved the problem by providing a network of storage that allows the multiple servers to share and access from separate networks of their own. The SAN is a dedicated and centrally managed information infrastructure that primarily provides communications and data transfers between computer nodes or interconnected devices, such as disks and tapes, storage nodes, servers or other devices. The SAN facilitates multiple users to access and share a pool of storage servers. Management of these types of systems plays an important role to secure the data access (i.e., who is authorized to access the data or who can access which devices and at what point in time.) 
     Fiber channel is a primary technology used in more recent SAN systems. Due to their high-speed, fiber channels enable the SAN to interconnect between servers and storage devices at data transfer rates of up to 200 Mbps in a dual loop configuration or 100 Mbps in a redundant mode. Typically, a fiber channel can be configured in various ways, such as a point-to-point configuration, a fiber channel arbitrated loops (FC-AL) configuration, and a switched fiber channel fabrics (FC-SW) configuration. The point-to-point fiber channel is a simple way to connect two devices directly together. The FC-AL includes a set of hosts and devices that are connected into a single loop. The FC-AL can support up to 126 devices and hosts on a single loop. In FC-SW, devices are connected in many-to-many topology using fiber channel switches. In this configuration, the number of devices that can be connected is unlimited. 
     A switched fiber channel fabrics FC-SW configuration employs at least one switched fiber channel fabric. A switched fiber channel fabric (or hereinafter “fabric”) is a collection of fiber channel switches that connect the individual devices in the many-to-many topology. A storage fabric is a collection of the many fiber channel switches that connect the individual devices (e.g., hosts, nodes) in a SAN. With all of the data stored in a single, ubiquitous cloud of storage, controlling which hosts have access to what data is extremely important. Zoning, in this respect, provides an isolation boundary for such management. 
     Zoning may be employed to group devices according to operating system, application, function, physical address, or other criteria as needed. Zoning separates the SAN into logical sub-networks. A port (e.g., host adapters or storage controller ports) can be configured as part of a zone. A port may separate a zone, or a SAN into physical sub-networks. The storage fabric may be configured so that only ports in a given zone can communicate with other ports in the same zone. Typically, zoning is implemented at the port level with zone access controlled by the ports configured to allow access or prevent access in the fabric, or zoning is implemented using simple name server (SNS) software that operates on the fabric switch. With zoning implemented using a SNS software, a node is identified using the node&#39;s world wide name (NWWN) and a port is identified using the port&#39;s world wide name (PWWN). Using SNS a defined zoning table may be developed listing devices by availability within a specific zone, and accessibility by a specific list of hosts. In either zone implementation when a host entity attempts to connect to a SAN and requests a list of available storage devices, the host will only receive access data for those storage devices that the host was configured to receive through a specific port configuration, or a defined zoning table. 
     Although the zoning in the SAN segregates storage access, zoning implicitly binds the technology of SAN (e.g., servers and storage arrays that can access each other through managed port-to-port connections). Devices within a specific zone can recognize and communicate with each other, but may not be able to with devices in other zones, unless a device in that zone is configured for multiple zones. Hence any change in the SAN topology may affect the localized zone or zones, and any change within a zone may affect SAN topology. 
     Due to the characteristics of the zoning in the SAN, there exist a number of problems in conventional SAN management. Certain devices may be required for specific zone deployments and configurations. In deployments supporting very important data storage, redundant devices (e.g., secure servers or hubs) provide added reliability and security, and assist with maintaining a zone&#39;s integrity. In addition to security and protective features, specific deployments may have certain devices configured for specific internal routines (e.g., redundant disk arrays for rapid data recovery). For example, when a node in the SAN becomes non-functional, replacing the non-functional node may disturb the overall zone integrity, especially if a replacement node is not available. With any change in a particular entity, for example changing from a functional node to a non-functional node, another entity will directly or indirectly perceive the change. Oftentimes, a change in a particular entity is promptly corrected, especially when the resources exist within the dedicated local area. However, with larger and more complex architectures, often containing many different systems specifically designed to operate separately, prompt management and resolution architectures are not always available, and changes in a particular entity might cause significant operational problems affecting an entire network or collection of network resources. Even when operational problems affect only a small amount of network resources, the changes may cause deleterious effects to the associated zone integrity. 
     What is needed is a system and method that relates generally to Topology-Static (TS) architecture within a computer system, and more particularly to the improved management of a Topology-Static architecture. 
     SUMMARY OF THE INVENTION 
     The foregoing problems are solved in accordance with the various illustrative embodiments of the invention in which a storage area network (SAN) management system is deployed to allow a user or administrator access to various management and monitoring routines operating throughout and or local to one or more addressable locations. The SAN management system coordinates the various management entities that are deployed throughout a large interrelated enterprise. The SAN management system primarily receives information concerning the SAN, through the information passed up through the network by the individual management entities. 
     Initially, the information received by the SAN management system will be related to the network design, deployed hardware, configuration parameters, and the topology for the specific zones of the network. Once deployed, the individual entities will begin to interrelate, and an actual topology will be discovered and recorded. From the initial deployment information, and the actual topology discovered, the SAN management system through a delegated manager and storage, will record the initial deployment information and use that initial deployment information when receiving any future indication from another management entity that there is a change in status that will affect, for example zone integrity and or interoperability. A localized manager (and/or managers) will respond to specific changes in the status of the devices in that area of the SAN. In the various embodiments, as a manager or managers manage the original change in status, a similar change in status created by the localized management, is perceived by further management entities, typically located above the localized area of the initial change in status in the logical architecture. In the various embodiments, a localized or semi-localized management entity will be able to delegate and or direct resources to seamlessly act in accordance with, for example a response/recovery routine, and attempt a correction in status. This layered management may translate from a switch level all the way up the architecture to the management entity reporting directly to a SAN manager. 
     After the initial topology and deployment information is received by a SAN manager, in various embodiments, the implicit interconnections including management and other configuration parameters are known to the SAN management system. Accordingly, in various embodiments, a user and or other authorized entity are able to closely examine certain aspects of those implicit interconnections that otherwise could not be ascertained. 
     In various embodiments, the actual topology discovered may be used to generate specific modeling and or abstractions for determining and targeting certain management aspects and routines. Certain abstractions may generate specific lists of hardware and or software (devices and programs) that may be useful for efficiently modeling and targeted routines. In still other embodiments, and after the actual topology has been discovered, and further focused to, for example, a switch level topography, an abstraction or model of the instances of a vendor specific switch may be determined. 
     Other objects, features and advantages of the invention will be apparent to those skilled in the art based on the following detailed description and the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an exemplary network enterprise in which the invention may operate according to the various embodiments of the invention; 
         FIG. 2  is an exemplary illustration of logical architecture of a storage area network entity stack, according to the various embodiments of the invention; 
         FIG. 3  is an exemplary illustration of a storage area network manager entity stack according to the various embodiments of the invention; 
         FIG. 4  is an exemplary illustration of a state diagram for a method to discover a topology-static zone according the various embodiments of the invention; 
         FIG. 5  is an exemplary illustration of a state diagram for a method to add a new member zone z to a topology-static zone according to the various embodiments of the invention; 
         FIG. 6  is an exemplary illustration of a state diagram to delete a member entity from a topology-static zone according to the various embodiments of the invention; 
         FIG. 7  is an exemplary illustration of a replacement of a node in the topology of the topology-static zone according to the various embodiments of the invention; 
         FIG. 8  is an exemplary illustration of a removal of a node in the topology of the topology-static zone according to the various embodiments of the invention; 
         FIG. 9  is an exemplary illustration of an insertion of a node in the topology of the topology-static zone according to the various embodiments of the invention; 
         FIG. 10  is an exemplary illustration of a disconnection of a loop to a switch in the topology of the topology-static zone according to the various embodiments of the invention; and 
         FIG. 11  is an exemplary illustration of a flow chart showing how an end user may execute exemplary topological operations according to the various embodiments of the inventive system. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  is an exemplary network enterprise  100  in which the invention may operate. As shown in  FIG. 1 , an enterprise network  100  may have one or more storage area networks (SAN) illustrated as a SAN  110 , a SAN  130  and a SAN  140 . These SANs may provide storage services used by enterprise network  100 . Also, as illustrated, SAN  110  includes one or more storage areas illustrated as a storage area  112 , a storage area  114  and a storage area  116 . SAN  130  and  140  may include other storage areas not illustrated. 
     Network enterprise  100  also includes a storage area network (SAN) manager  120 . The SAN manager  120  provides centralized management for the storage areas directly or indirectly under its control throughout the enterprise network  100 . Network enterprise  100  may also include one or more localized or local area networks (LAN)  160  and  170 , a larger less localized or wide area network (WAN)  180  and a user or administrative entity  150 . The above entities are operatively coupled to and may communicate between or through each other. 
       FIG. 2  illustrates a logical architecture of a SAN entity stack  105 ( n ). SAN entity stack  105 ( n ) may, for example, be described as a coordinated architecture spanning one or more separate layered architectures. As will be appreciated, the invention may be applied to logical architectures including one or more entity stacks  105  (illustrated in  FIG. 1  as a SAN entity stack  105 ( 0 ), a SAN entity stack  105 ( n+ 1) in addition to SAN entity stack  105 ( n )). 
     For ease of description, entity stack  105  may also be represented as entity stack E n  wherein n may represent any number or otherwise designate a specific entity stack. Entity stacks  105  represent an abstract, a high-level, logical layered, architecture for various components and/or elements of the SAN  110 . As illustrated, entity stack  105  includes: a switch  270 , a switch manager  275 , a node  260 , a node manager  265 , a first loop  240 , a second loop  250 , an interface manager  245 , a first zone  220 , a first zone manager  225 , a second zone  230 , a second zone manager  235 , and a fabric  210 . 
     For purposes of this discussion, switch  270  corresponds to the lowest level or layer in entity stack  105 ; followed by a layer corresponding to node  260 ; followed by a layer corresponding to both second loop  250  and first loop  240 ; followed by a layer corresponding to both second zone  230  and first zone  220 ; and followed by the upper-most layer corresponding to fabric  210 . Also for purposes of this discussion, switch manager  275  is associated with switch  270 ; node manager  265  is associated with node  260 ; second loop  250  and first loop  240  are associated with one or more interface managers  245 ; second zone manager  235  is associated with second zone  230 ; and first zone manager  225  is associated with first zone  220 . 
     Each individual layer of entity stack  105  serves a specific purpose, perform specific functions, and/or provide support to SAN  110 . Switch  270  and switch manager  275  represent a lowest logical layer and may correspond to the circuit and/or chip level within a particular device operational in a SAN  110 . The switch manager  275 , for example, may monitor and manage specific routines and parameters suited for operation of switch  270  including the specific configuration, provisioning, and discovery operations. For example, switch manager  275  may determine a position and or state (enabled high or low) of switch  270 . 
     Entity stack  105  includes node  260  and node manager  265 . In other various embodiments entity stack  105  represents the device level and may correspond to a network appliance, a router, a hub, a stand alone addressable port, or another entity that would have an IP address or employ TCP/IP protocols operational in a SAN. The node manager  265 , for example, may monitor and manage specific routines and parameters suited for an individual node  260 , or any operable entity with an IP address at this layer. 
     The second loop  250 , the first loop  240 , and the interface manager  245  represent the devices and or applications that are cooperatively deployed in a loop, for example an application that has shared resources located on more than one node. Accordingly, if one device and/or application were to become non-operational, the loop may not remain operational. The interface manager  245  may monitor and manage specific routines and parameters suited to an individual loop, and may take corrective measures if one or more of the devices and or applications were determined non-operational. In addition to the general parameters, the interface manager  245  may maintain a category of secure parameters indicative of a specific type of loop. These secure parameters (discussed in more detail below) relate to the state of a particular zone and may, for example, manage restrictive or otherwise secure loops in a SAN  110 . 
     The second zone  230 , the second zone manager  235 , the first zone  220 , and the first zone manager  225  are provisioned as a topology-static zone. This layer represents one or more zones that include all of the attendant resources found within managed storage architecture. Management for a second zone  230  and a first zone  220  may be found directly within this layer and/or indirectly within SAN manager  120 . In addition, according to various embodiments of the invention a zone may also be managed and provisioned as either a topology-static strict zone or a topology-static loose zone (discussed in more detail below). 
     The uppermost layer includes fabric  210 . The uppermost layer may be directly managed by a management entity within the uppermost layer (not shown) or indirectly managed by a management entity found within a SAN manager  120  (shown in  FIG. 3 ). The upper-most layer represents a high-level topographical view of the individual layers of a given entity stack  105  for the SAN manager  120 . 
       FIG. 3 . illustrates a logical SAN manager entity stack  300 . SAN manager entity stack  300  represents an abstract, high-level, logical layered, architecture for various systems, components and/or elements of the SAN manager  120 . As illustrated SAN manager entity stack  300  includes: a SAN monitoring module  310 , a fabric level manager  320 , and a zone level manager  330 . In various embodiments and as indicated above, SAN manager entity stack  300  includes a zone level manger  330  for managing second zone  230  and/or a first zone  220 , and a fabric level manager  320  for managing any fabrics within SAN  110 . 
     As illustrated in  FIG. 3  and in some embodiments, SAN manager entity stack  300  includes a monitoring module  310  which has specific responsibilities including monitoring the device configuration for the entire SAN  110 , and maintaining a registry of the responses that the monitoring routines may generate. In some embodiments, monitoring module  310  may be monitoring some event that triggers a change in topography. In various embodiments, SAN monitoring module  310  may monitor for specific events that may affect the topology of SAN  110  including: discovering a topology-static zone; creating a topology-static zone; deleting a topology-static zone; renaming a topology-static zone; adding a member entity to a topology-static zone; removing a member entity from a topology-static zone; adding a topology-static zone to a zone collection; and removing a topology-static zone from a zone collection. 
     When a change in topography is discovered, the affected topology-static zone may set a signal or flag to indicate that a zone has perceived the change in topology. In some of the various embodiments, the affected topology-static zone may set a signal I. Once a zone sets a signal “I” other devices or other zones are alerted to that change in topology, and must similarly set a signal “I” and evaluate their own localized topology and determine whether a change in topology has occurred. Specific event triggers for a zone setting a signal to “I” are discussed below. Further, while “I” is only symbolic of the underlying event, for simplicity “I” will represent intimating. For purposes of this description, an intimating signal is meant to convey an indirect message from the source to the manager that a change in topography is discovered within a topology-static zone. 
     One triggering event that might set an intimating signal within a topology-static zone is the addition or removal of any public device or devices found within a loop, for example first loop  240  or second loop  250 . When discovering such a change in first loop  240 , the first zone manager  225  will set a signal in topology-static zone  240  to “I”. In various embodiments, after setting a signal “I”, first zone manger  225  may await a response from SAN manager  120  before taking any action. SAN manager  120  may poll all the addressable entities within, for example, SAN  110  to receive a complete status of the entire architecture for SAN  110 . SAN manager  120  may then compare the current status of the entire architecture of SAN  110  with a stored record of the most recent architecture for SAN  110  to determine whether an overall change in topology occurred. At the same time, or shortly after setting the signal “I”, first zone manager  225  may send a signal “I” directly to SAN manager  120  to alert the SAN manager  120  concerning a localized change caused by the removal of a public device. One illustrative embodiment may involve the removal of a non-operational device within a first loop  240 . When interface manger  245  discovers that a device located on first loop  240  is non-operational, interface manger  245  would set a signal to “I”. A signal “I” set by the interface manager  245  would be discovered within a local zone, for example first zone  220  and first zone manager  225 . Similarly first zone manager  225  would set a signal to “I”, and that signal would be discovered by a fabric  210  and a fabric level manager  320 . Similarly fabric level manager would  320  would set a signal to “I”, and that signal would be discovered by SAN monitoring module  310 . As these individual signals are being set, interface manager  245 , first zone manager  225 , and fabric level manager  320  may start to determine whether resources may be available to restore the topology to a pre-signal “I” status. Interface manager  245 , first zone manager  225 , and fabric level manager  320  may in various embodiments, poll the other devices they manage to determine whether a replacement device is available, and if available whether the replacement of a non-operational device by a specific operational device would be permitted by SAN manager  120 , and if permitted, what affect the replacement may have to the overall topology of SAN  110 . Once responses to the poll are received by SAN manger  120  and/or the time period for response has passed, SAN manager  120  may generate a current status of the original device or location that set a signal “I”, and the entire zone. In addition to a report of the current status (which SAN manager  120  may transfer to SAN monitoring module  310 ), SAN manager may also extract from SAN monitoring module  310  a schedule of corrective actions that may be directly communicated back to the local manager entity, first loop manager  225 . Next in various embodiments the SAN manager  120  may attempt to determine whether the zone supporting the original change in status, is a topology-static zone. 
     In various embodiments, before any corrective action may take place within a specific zone or zones, SAN manager  120  may determine whether the corrective action is permitted. Certain requests for corrective action may immediately manifest either a permission, or a denial. Other requests may be evaluated further by, for example, first zone manager  225 , and/or further management entities including SAN manager  120 . Requests may be sent from interface manger  245 , and these requests may include the following: discovering, creating, deleting, and renaming a topology-static zone; adding/removing a member entity to/from a zone; and adding/removing a topology-static zone from a collection of zones, or a zone set. 
     After first zone manager  220  receives and determines that a particular request is not manifestly unauthorized, and according to various embodiments first zone manager  220  may then redirect those requests to a switch manager, for example switch manager  275 . In some embodiments of the invention, once these redirected requests are received and acknowledged by switch manager  275 , SAN monitoring module  310  may be updated to reflect the request and/or event requested. SAN manager  120  may not need to coordinate the polling between first zone manager and switch manager  275  after first zone manager  220  receives a successful acknowledgement from switch manager  275 , or vice versa. A successful acknowledgement establishes that first zone manager  220  and switch manger  275  are allowed to communicate; however any action by either first zone manager  220  or switch manager  275  must be coordinated by SAN manager  120 . 
     Also, and as in various embodiments, if either first zone manager  220  or switch manager  275  detects a change in status, that change in status may be directly communicated to SAN manager  120 . When acting under the direction of SAN manager  120 , any topological change may be recorded and stored within SAN monitoring module  310 . After updating SAN monitoring module  310 , and in various embodiments first zone manager  220  may receive a signal indicating the status change from SAN monitoring module  310 . Next and in various embodiments, first zone manager  220  may decide if the change occurring in a specific loop, for example first loop  240 , may be caused by or triggered by an individual node from within a specific topology-static zone, for example first zone  220 , setting a signal “I”. At this point in the evaluation first zone manager  225  may be primarily concerned with any nodes that indicate a change in status with a set signal “I”; however all of the nodes may be polled with their responses recorded by SAN manager  120 . 
       FIG. 4-FIG .  6 , illustrate various methods employed by SAN manager system  120 .  FIG. 4  illustrates a state diagram  400  for discovering a topology-static zone. Pursuant to  FIG. 4  and as in various embodiments, after initialization first zone manager  225  may initiate a discovery operation  401 . Discovery operation  401  may include first zone manager  225  requesting status information from switch manager  265 . In addition to the status information concerning the lowest layer containing the switch manager  265 , any response sent to first zone manager may also contain the entire collection of zone information within switch manager  265 . In accordance with the various embodiments, an examination of the information passed may determine whether fabric-to-loop interconnection is associated with specific port identification. One example, according to illustration  FIG. 4 , to determine whether first zone possesses interconnection with specific port identification may be to examine any entity information contained in the information passed from switch manager  265  to first zone manager  225 , for specific port identification. Only the previously polled and successfully acknowledged entities within a zone, for example first zone  220 , may possess a valid port address.  FIG. 4  illustrates a state diagram  400  that may be used to discover a topology-static zone in some exemplary embodiments. State diagram  400  may be stored within SAN monitoring module  310  and activated during an initial evaluation after discovering a change in status by SAN manager  120 . Determining whether the zone in which a change in topology has taken place, is a topology-static zone is important since specific resources and corrective deployments may only be available to a topology-static zone. One method to determine whether the zone affected by a change in topology is a topology-static zone might be the evaluation of certain prior criteria associated with that zone (e.g., whether the zone was previously classified a topology-static zone), or other current characteristics of the particular zone. Exemplary state diagram  400  uses specific notations and symbols, including: D for domain meaning the entire collection of entities within SAN  110 , F for fabric meaning fabric  210 , and FL_Port for fabric-loop port meaning the addressable location for interconnection or connection between fabric  210  and a loop, for example first loop  240 , to evaluate certain previous criteria and/or current characteristics of a specific zone. By following the operations through exemplary state diagram  400 , discovery of a topology-static zone may be confirmed. 
     As illustrated in  FIG. 4  and according to an exemplary embodiment, a specific instance for a method to discover a topology-static zone. The method employs a topographical-based decision engine to process an individual zone z and determine whether a zone z is a topology-static zone. During the process illustrated in  FIG. 4 , the state of a zone z is put through a series of evaluations. After each evaluation, the state of zone z may or may not undergo a transition. It should be understood that a state following any operation prior to the final evaluation in the process illustrated in  FIG. 4  may only be temporary, and may not indicate a final state for a zone z. 
     At operation  401  the process requests a member of zone z for evaluation. After receiving a member of zone z, zone z is evaluated to determine whether zone z belongs to a collection of previously identified topology-static zones. If operation  401  determines that zone z belongs to a collection of previously identified topology-static zones, the process continues to operation  402 . Contrarily, if operation  401  determines that zone z does not belong to a collection of previously identified topology-static zones, then process proceeds to operation  403 . At operation  403  the state for zone z becomes a non-strict topology-static zone, and process proceeds to operation  406 . At operation  406  zone z is evaluated to determine if zone z is defined by a F/FL_Port. If zone z is not defined by a F/FL_Port, the process loops back to operation  403  and requests the next zone z( 2 ). If the next zone z( 2 ) is not a member of the collection of previously identified topology-static zones, or there are no further members to request, then the state for zone z becomes a non-strict topology-static zone. 
     At operation  406  a third condition may exist if a F/FL_Port is not found. If operation  406  determines that a F/FL_Port is not found, the process proceeds to operation  410 . At operation  410  the process may indicate F/FL_Port not found, and the process continues to operation  412 . At operation  412  the process may indicate Not a Member. Additionally, when all members of a zone z have been evaluated, operation  412  may indicate End of Members. In both cases, and after operation  412  indicates Not a Member or End of Members, the process may indicate that the state has transitioned to a non-strict topology static zone. 
     If at operation  406  zone z is defined by a F/FL_Port, the process proceeds to operation  407 . At operation  407  the state for zone z becomes a loose topology-static zone. 
     If zone z is a member of the collection of previously identified topology-static zones process proceeds to operation  402 . If operation  402  determines that zone z is defined by a F/FL_Port or a next zone z( 2 ) is defined by a F/FL_Port, process will proceed to operation  404 . At operation  404  the state for zone z becomes a strict topology-static zone. However, if at operation  405  zone z is not defined by a F/FL_Port or at operation  408  next zone z( 2 ) is not defined by a F/FL_Port, the state becomes F/FL_Port not found. 
     As  FIG. 4  illustrates, if the current state is loose topology-static zone, any additional member of the collection of previously identified topology-static zones will not affect that current state. At the end of the decision engine illustrated in  FIG. 4 , all states except for F/FL_Port not found, will not affect that current state. When the decision engine ends on an unknown member, all states will become an error state. When the decision engine ends with either a state being strict topology-static zone or a state being a loose topology-static zone; zone z is classified accordingly. 
     As illustrated in  FIG. 5  and according to an exemplary embodiment, is a specific instance for a method to add a new member zone z to a topology-static zone. In general, as illustrated in  FIG. 5 , when a new member is added to a topology-static zone, the topology-static zone may change under certain conditions. As illustrated in  FIG. 5  is state diagram  500 , after initialization process proceeds to operation  501 , and member x is added to a zone z. After a member x is added to zone z, the process proceeds to operation  502  and member x is evaluated to determine if member x is part of the collection of predetermined members of a strict topology-zone. If member x is part of the collection of predetermined members of a strict topology-zone, adding member x to a strict topology-static zone will not change the state of zone z. However, if at operation  502  member x is evaluated and is not part of a previous collection of predetermined members of a strict-topology zone, process proceeds to operation  503 . At operation  503 , with the addition of a member x, the state of zone z is a loose topology-static zone. Furthermore, once zone z may be determined a loose topology-static zone, adding any new member to zone z will not trigger a change in state. 
     As illustrated in  FIG. 6  and according to an exemplary embodiment, is a specific instance for a method to delete a member zone z from a topology-static zone. In general, as illustrated in  FIG. 6 , when a member is deleted from a topology-static zone, the topology-static zone may change under certain conditions. As illustrated in  FIG. 6  and after initialization, at operation  601  an evaluation to delete a member entity x from a topology-static zone may be manifest in two cases: the first based on the determination at operation  601 , whether the topology-static zone is a strict topology-static zone; and the second based on the determination at operation  602 , whether the topology-static zone is a loose topology-static zone. 
     Consider, for example, that a topology-static zone is a strict topology-static zone. At operation  603  a member entity x may be deleted from a topology-static zone z, with x defined by F/FL_Port. Also, consider a member entity y, with y not within topology-static zone z or equal to x. Still further, y is defined by F/FL_Port. As shown by operation  605  and operation  604 , topology-static zone z may be determined a non topology-static zone. Otherwise, and as shown in operation  606 , topology-static zone z will remain a strict topology-static zone. 
     Consider, for example, that a topology-static zone is a loose topology-static zone. At operation  607  a member entity x may be deleted from a topology-static zone, with x not part of the group of predefined members of a topology-static zone. Another condition may exist at operation  607  indicating a member entity x is the last entity of a group. Also, consider for example, a member entity y, with y not within topology-static zone z, not equal to x, and not part of the group of predefined members of a topology-static zone. In both cases, if either x is the last entity of a group, or a member entity y, with y not within topology-static zone z, not equal to x, and not part of the group of predefined members of a topology-static zone, then, as shown in operation  608  a topology-static zone Z may be determined a Strict TS-Zone. 
     Also, if x may be defined by F/FL_Port, and there may exist a member entity y, with y not equal to x. Additionally, y is defined by F/FL_Port, then as may be shown by operation  609  topology-static zone Z may be determined a non topology-static zone. At operation  610 , if neither determination is made (either a strict topology-static zone or non topology-static zone) the topology-static zone z may remain a loose topology-static zone. 
     When a topology-static zone z is sets a signal to “I”; changes in the topology will also trigger changes in the topology-static zone.  FIGS. 7-10  illustrate various cases in accordance with various embodiments of the invention. 
       FIG. 7  illustrates a replacement of a node in the topology of the topology-static zone. In this example, a public node (n 1 ) of a specific public loop is found within a topology-static zone z. Replacement of a node is defined as the deletion of public node n 1  and the insertion of a public node n 2 . The insertion of a node n 2  will happen at the port previously occupied by a node n 1 , and within a specific time interval (Δt). 
     Therefore, when a topology-static zone z sets a signal to “I”, and a public node (n 1 ) is a member of the collection of entities of topology-static zone z, the replacement of node n 1  with public node n 2 , will be monitored by the SAN manager  120 . 
       FIG. 8  illustrates a removal of a node in the topology of the topology-static zone. In this example, a public node (n 1 ) of a specific public loop is found within a topology-static zone z. The member node n 1  is removed, unplugged, or otherwise deactivated. With the removal of a member node n 1 , the node will no longer be monitored by the SAN manager  120 . 
       FIG. 9  illustrates an insertion of a node in the topology of the topology-static zone. In this example, a public node (n 1 ) is inserted into a public loop found within a topology-static zone z. The member node n 1  is connected, and considered inserted into the loop when the node is discovered. With the insertion of a node n 1 , the node will be discovered during the monitoring by the SAN manager  120 . 
       FIG. 10  illustrates a disconnection of a loop to a switch in the topology of the topology-static zone. In this example, a loop is disconnected from a switch within a topology-static zone z. The member entities of the specific loop, when disconnected from a switch, are considered removed from the topology-static zone z. The disconnection of the loop prevents further monitoring of any member entities of the loop, by the SAN manager  120 . 
       FIG. 11  illustrates a flow chart  1100  showing how an end user or administrator  150  may execute exemplary topological operations pursuant to the various embodiments of the invention. To start this process the end user will initiate a call to a system supporting the SAN manager  120 . The inquiry may then indirectly or directly, at operations  11001 - 11002 , trigger a first determination whether a public node has been added to, or removed from a specific public loop within a topology-static zone z. As illustrated in  FIG. 11 , if the determination indicates that a public node has not been added to, or not removed from a specific public loop, the operation may return to step  11001  and await the next polling cycle or similar trigger. If the determination indicates that a public node has been added to, or removed from a specific public loop, the process will proceed on to operation  11003 . 
     At step  11003  the process will update the information maintained within SAN monitoring module  310 , and review all the necessary and related information maintained at SAN monitoring module  310 . Information maintained at SAN monitoring module  310  may be deemed necessary and related to a given update, especially if the information concerns the same entity type as the entity type that affected the topology (e.g., first zone manager  225  may contain information relevant to second zone manger  235 , and vice versa). In other words, if a node has been added to an existent public loop, the collection of nodes on the existent public loop has changed by the addition of a new node. From the perspective of the public loop, there has been a change in topology. 
     The SAN manager  120  may poll a given public loop, review all the present entities, call SAN monitoring module  310  and review the collection of entities related to the given public loop. After completing the review of the related entities, the SAN manager  120  may determine which information is necessary for updating SAN monitoring module  310 , as well as if any information must be processed further, or whether any information must be gathered from an additional source, or whether any information is ready for communication to an end user, or whether the SAN manager  120  may allow the specific process to end. 
     In addition to information gathered from a direct change in a topology status, the SAN manager  120  may also monitor and maintain a record of indirect information about a specific change in a topology status. An example of such indirect information may be the time period between topology status events. Further, if the SAN manager  120  detects a topology change, such as the insertion of a new node, SAN manager  120  may then actively tailor future time periods to poll the status more frequently. A more frequent polling routine would be very useful when an additional entity is added, especially when the additional entity is further discovered up through the logical levels of hierarchical control and management in a particular architecture. 
     Conversely, a polling routine may occur less frequently when an entity is removed. Accordingly, with the removal of a given entity, the management overhead is incrementally reduced. Further, the same incremental reduction would be apparent at each level of hierarchical control and management in a particular architecture. 
     In operation  11006 , and if one node n 1  is replaced by another node n 2 , then the process will remove the entity node n 1  from a topology-static zone z, and further add the entity node n 2  to a topology-static zone z. For ease of description, we will present an example where the replacement node is placed in the position previously occupied by the original node. 
     In operation  11007 , the process may monitor switch manager  275 , and may incorporate the event-driven change into SAN monitoring module  320 . In such a case and at operation  11008 , the SAN manager  120  may not need any further direct determinations concerning a substitution. 
     In operation  11009 , the process may determine that the topology status change is a deletion of a node. In accordance with the deletion of a node from topology-static zone z, the process will simply remove the node from the architecture where it had been previously. The process may monitor switch manager  275 , and may incorporate the topology status change into SAN monitoring module  310 . The two operations involving the replacement and the removal of a specific node are accomplished at the lowest logical level corresponding to switch  270 . However, the inventive concepts of the subject invention are not limited to such a simplified substitution. Rather, as will be apparent to those skilled practitioners the concepts are easily portable and scalable for various hardware and software architectures and deployments. 
     If the process successfully removes or replaces a specific node, the process continues on to operations  11010  and  11011 . At operation  11011 , the process updates the information at various locations including, the graphical user interface (GUI) manager  245 , to present a successful notification to a user  150 . In addition, at step  11011 , the SAN manager  120  may store the successful record in SAN monitoring module  310 . However, if the process has not been successful, an error message or some similar indication will be displayed upon GUI manager  245  to present notification to the user. 
     While this invention has been described in conjunction with the exemplary embodiments outlined above, it is evident that many alternative, modifications and variations will be apparent to those skilled in the art. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the invention, and the following claims are intended to cover such modifications and changes.