Abstract: Resource availability profiles are received, wherein each resource availability profile describes a resource associated with a server. Each resource is assigned a plurality of weights corresponding to a plurality of policies. The weights are determined by, for each of the plurality of the policies, determining a weight for each resource based a given policy and selected information in the resource availability profiles corresponding to the resources. The method further comprises determining a policy from the plurality of the policies corresponding to a given a context associated with a connection request. A first of the load-balanced servers is selected for the connection request based on the weights assigned to the plurality of resources for the policy for the given context.

Abstract: A method and system for processing directives included in management events are disclosed. A method for handling management events includes detecting an event generated upon an occurrence relating to a device, such as a network device. The device related occurrence has a characteristic. A directive, appropriate to this characteristic, is included with the event format. The event is directed to a management entity, which interprets the directive and handles the event by processing it according to the directive. Such preprocessing directives included in the events allow recipients of the events to decide what to do with them, e.g., with the messages therein, and thus help prevent inadvertent loss of information conveyed in these events.

Abstract: An approach for processing events generally involves receiving event data that specifies one or more attributes of an event that has occurred. A determination is made whether the event data satisfies one or more event cancellation criteria. If so, then event report data is provided to a recipient, such as an application layer. The event report data specifies at least one attribute of the event that occurred. If the event data does not satisfy the one or more event cancellation criteria, then the event data is not provided to the recipient and the event is canceled. The cancellation criteria may include policy-based rules that may specify event cancellation based upon, for example, event frequency, correlation window size, particular information associated with an event, or other management application rules. The particular cancellation criteria used may vary from application to application. Furthermore, the cancellation criteria used for any particular application may be dynamic and change over time.

Abstract: Event processing in rate limited network devices is described. An event receiver is notified of a backlog condition and may respond by increasing the rate limit for the network device. If an event queue on the network device overflows, event messages may be diverted to an event message overflow store or to a network location. Later, the messages may be retrieved after the overflow condition has cleared. As a result, critical messages or events such as Syslog messages are not lost when a rate limited network device cannot deliver the messages to a network management station.

Abstract: A method is disclosed for a method for measuring the availability of a network element or service. For each network element N, a current real availability value CRAVN and a current time value CTVN are associated with network element N. Additionally, for each network element N, an operational state value OSVN is associated with network element N. At a later time, indicated by a new time value NTVN, a new real availability value NRAVN for network element N is determined based on the current availability value CRAVN, the current time value CTVN, the new time value NTVN, and the operational state value OSVN. The new real availability value NRAVN is stored. Thus, each separate network element N may be associated with a separate real availability value that accurately reflects the availability of network element N specifically, regardless of any availability approximated for network element N's type.

Abstract: Event processing in rate limited network devices is described. An event receiver is notified of a backlog condition and may respond by increasing the rate limit for the network device. If an event queue on the network device overflows, event messages may be diverted to an event message overflow store or to a network location. Later, the messages may be retrieved after the overflow condition has cleared. As a result, critical messages or events such as Syslog messages are not lost when a rate limited network device cannot deliver the messages to a network management station.

Abstract: A method is disclosed for adaptively coupling processing components in a distributed system. In one aspect, a second component requests an interaction with a first component by sending a service access request to access a first service of the first component. The service access request specifies parameters relating to a proposed level of coupling between the first component and the second component. The second component receives a service response from the first component; the service response specifies counter-proposed parameters relating to a proposed level of coupling between the first component and the second component. The second component determines whether the service response indicates that the first service may be provided. If so, then an agreed-upon level of coupling is established between the first component and second component, and the components interact to receive the service. The level of coupling among the components may be re-negotiated at any time by exchanging values in a coupling context.

Abstract: A method is disclosed for adaptively coupling processing components in a distributed system. In one aspect, a second component requests an interaction with a first component by sending a service access request to access a first service of the first component. The service access request specifies parameters relating to a proposed level of coupling between the first component and the second component. The second component receives a service response from the first component; the service response specifies counter-proposed parameters relating to a proposed level of coupling between the first component and the second component. The second component determines whether the service response indicates that the first service may be provided. If so, then an agreed-upon level of coupling is established between the first component and second component, and the components interact to receive the service. The level of coupling among the components may be re-negotiated at any time by exchanging values in a coupling context.

Abstract: A method is disclosed for adaptively coupling processing components in a distributed system. In one aspect, a second component requests an interaction with a first component by sending a service access request to access a first service of the first component. The service access request specifies parameters relating to a proposed level of coupling between the first component and the second component. The second component receives a service response from the first component; the service response specifies counter-proposed parameters relating to a proposed level of coupling between the first component and the second component. The second component determines whether the service response indicates that the first service may be provided. If so, then an agreed-upon level of coupling is established between the first component and second component, and the components interact to receive the service. The level of coupling among the components may be re-negotiated at any time by exchanging values in a coupling context.

Abstract: The real time availability of a group of network elements is determined based upon both a real time availability value for each of the network elements and cooperation relationships between the network elements. The cooperation relationships reflect both the topological relationships between the network elements, i.e., how the network elements are connected, and the extent to which network elements interact with each other effectively. For relatively small groups of network elements, where the cooperation relationships are not overly complex, the real time availability is determined directly from the real time availability value for each of the network elements and cooperation relationships between the network elements. Decomposition and recombination are used to determine the real time availability of large groups of network elements based on specific formulas for basic network element topology models.

Abstract: Resource availability profiles are received, wherein each resource availability profile describes a resource associated with a server. Each resource is assigned a plurality of weights corresponding to a plurality of policies. The weights are determined by, for each of the plurality of the policies, determining a weight for each resource based a given policy and selected information in the resource availability profiles corresponding to the resources. The method further comprises determining a policy from the plurality of the policies corresponding to a given a context associated with a connection request. A first of the load-balanced servers is selected for the connection request based on the weights assigned to the plurality of resources for the policy for the given context.

Abstract: Methods and mechanisms for preventing deadlock in a policy-based computer system are disclosed. In one embodiment, the method includes various machine-implemented steps, such as a step of receiving policy information based upon decisions about system configurations. At least one policy includes at least one action that has a post condition. Satisfaction of the post condition triggers at least one subsequent action or decision. The policy includes an indication whether the at least one subsequent action or decision should proceed if the action fails to satisfy the post condition. The at least one action is executed. Then, if the action fails to satisfy the post condition, a determination is made whether the at least one subsequent action or decision can proceed based upon the indication.

Abstract: An approach is provided for characterizing the dynamic availability behavior of network elements using metrics that indicate patterns of availability of a network element over time. The metrics provide an indication of stability and instability of a network element and include one stability metric and three instability metrics. The stability metric is a stability order that indicates how long an operational state holds with respect to a prior operational state. The instability metrics include an instability order, a repeatability order and a multiplicity order. The instability order indicates how quickly a network element changes operational states. The repeatability order indicates short-term instability within a vicinity of a change in operational state. The multiplicity order indicates long-term instability. The metrics may be used alone, or in various combinations, by network management applications to better manage network elements.