Abstract: Techniques for mapping availability management (AM) functions to software installation locations are described. An availability management function (AMF) can look-up a component type and determine software associated with that component. For a selected AMF node, the AMF software entity can then determine a pathname prefix associated with that software. The pathname prefix can then be used for various AM functions, e.g., instantiation of a new component or service unit.

Abstract: Service upgrade methods and systems for HA applications are described. System level and application level techniques for routing service requests before, during and after service upgrades are illustrated.

Abstract: A method for maintaining a current view of a cluster's membership comprising the steps of maintaining a list of member nodes and updating the list when a modification thereto is noticed by a first node by receiving a first update message from the first node in a second node, thereafter, sending a second update message from the second node to a third node to propagate the modification and sending to the first node a first confirm message from the second or the third node. A node member of a cluster capable of maintaining a first list of neighboring nodes, maintaining a second list of neighboring nodes sharing a current view therewith and ensuring that the first list matches the second by exchanging messages with neighboring nodes, wherein each message comprises topology information. Upon confirmation that both lists match, the node being capable of sending a confirmation message toward neighboring nodes.

Abstract: Methods for providing feedback in messaging systems are described. A communication node can include a first counter for counting a first number of messages which received by and/or forwarded by the node. The communication node can also include a second counter which counts a second number of messages which are expected to be delivered from that node to other nodes.

Abstract: A distributed model for availability management (AM) functions is described. Core AM functionality is provided by at a global level, while supplemental AM functionality is provided at a local (e.g., cluster) level. Extension entities can be provided to supplement provided AM functions.

Abstract: A node member of a cluster in a network comprising a plurality of nodes and a method related to the capabilities of the node, which is capable of maintaining a stable view of the cluster's membership, maintaining a list of neighboring nodes sharing a same updated view of the cluster's membership and receiving a confirmation message from a second node confirming that a new view received therein should replace the stable view and become a new stable view. The node is further capable of verifying that the new view is up to date in comparison to the same view and, if the new view is not up to date, discarding the confirmation message.

Abstract: A method and hardware node for carrying out a customized upgrade process of an application module or a platform module is provided. Modules interested in receiving notifications about upgrade processes register their interest with an upgrade manager. The manager is then provided with a set of instructions, such as a script, that associate certain criteria with notifications to be transmitted to interested application modules, which registered with the upgrade manager. When an upgrade of an application module is initiated, the manager determines whether the criteria is satisfied and if so, sends the proper notifications to the registered modules, which may take appropriate action, such as executing a given task or adapting their behaviour taking into consideration the ongoing upgrade process. The invention is for both standalone hardware nodes implementing application module(s) and for redundant, distributed or cooperating applications of high availability systems.