3com Corporation

Sepaton, Inc.

Hewlett-packard Company

Jane Riegel

Jacek A Tulacz

John M Livingston

John Chernoch

Kin Moon Leung

Francisco Aquino

Raphael J Weyman

David Reinauer

Described are computer-based methods and apparatuses, including computer program products, for system health monitoring. Backup set metadata is received, wherein the backup set metadata comprises information about backup data sets that are received by a backup storage system. One or more processes that process the backup set metadata through an emulated processing flow path are executed, wherein the one or more processes are also implemented in the backup storage system. Two or more potential processing states are determined within the emulated processing flow path. A reason code is determined for each backup set metadata entry of the backup set metadata indicative of a reason that the backup set metadata entry is in a processing state of the two or more potential processing states. A problem with the manner in which the backup set metadata is flowing through the emulated processing flow path is identified based on the reason codes.

System health monitor

Backup set metadata is received, wherein the backup set metadata comprises information about backup data sets that are received by a backup storage system that stores the backup data sets. The manner in which the backup data sets flow through a processing flow path of the backup storage system is emulated. One or more processes that process the backup set metadata through an emulated processing flow path are executed, wherein the emulated processing flow path is indicative of the manner in which the backup data sets flow through the processing flow path of the backup storage system when the backup storage system stores the backup data sets. One or more timing statistics are calculated based on the flow of the backup set metadata through the emulated processing flow path.

A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g., the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronisation of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit. The synchronization allows the running of the routing protocol on multiple physical routers in a stack without requiring the overhead of a back-up unit that would not perform routing unless a master router unit became unavailable.

Stackable routers employing a routing protocol

A stack of network routers is composed of at least one (elected) master unit and one or more slave units each capable of running a routing protocol. Only the master unit runs the entire routing protocol at a given time. It forwards direct update messages via a transmission control protocol to each of the slave units. These direct update messages may include specific packet formats for the protocol state machinery where such machinery is required by the routing protocol, e.g. the interface state machine and the neighbor state machine for the OSPF protocol, and for the net databases, e.g. the link state databases for the OSPF protocol, in each of the slave units. Each slave unit may run its protocol state machinery (where provided) based purely on the direct update messages received from the master. The synchronization of the net databases may be based on snooping net update packets and a comparison of the information received thereby with verification data messages sent from the master unit. The synchronization allows the running of the routing protocol on multiple physical routers in a stack without requiring the overhead of a back-up unit that would not perform routing unless a master router unit became unavailable.

A network unit comprises a multiplicity of ports for transmitting and receiving data packets, a bridging facility and a routing facility. The network unit has a multiplicity of mutually exclusive states which includes an initial state from which said network unit can transition to either a slave state; or a waiting state from which in the absence of receipt from elsewhere of a broadcast advertisement including an advertised address corresponding to an address of the unit, the unit transitions to a master routing state in which the routing facility is enabled and the unit broadcasts a corresponding advertisement including an address of the unit. The unit transitions from the waiting state, when it receives from elsewhere (i.e., another unit) such a broadcast advertisement, to a master bridging state in which the routing facility is disabled and the unit provides commands for disabling a routing facility of other similar units to which the network is connected. The states include a slave routing state, in which the routing facility is enabled, and a slave bridging state, in which the routing facility is disabled. In the slave states the advertisements are not broadcast and the unit responds to routing enabling and disabling commands from a unit in a master state. The scheme provides in conjunction with external connectivity resilience in the event of a cascade failure.

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Marlborough, MA, United States of America

Jane Riegel