Abstract: A method of identifying an egress port of a focus device, the method being implemented at a monitor computer and comprising: generating a query message to the focus device including an address identifying the device and a query key formulated based on a destination identifier, and including an instruction readable at the device to return the result message including identification of an egress port for messages addressed to the destination identified in the destination identifier; receiving a result message at the monitor computer; reading the result message, and where the result message does not identify an egress port autonomously generating a subsequent query message; including at least one of (i) a different address for a different device connected in the computer network, and (ii) a different query key, wherein sufficient query messages are generated to identify the egress port of the focus device.

Abstract: Computer implemented methods are disclosed that include identifying a next hop from a focus device in a path of interconnected devices including switching and routing devices, wherein a switching device operates according to a switching address protocol and a routing device operates according to a routing address protocol. The methods may include, for a focus device which is configured to receive traffic addressed to a terminal destination and to act as a routing device, dispatching a query message containing a query key based on an identifier for the terminal destination from a management computer to the focus device to identify the next routing address; receiving a result message containing a new routing address; and ascertaining from the new routing address the corresponding switching address, wherein the switching address is usable in a query key for a query directed to a focus device which is a switching device.

Abstract: A method of executing a loop computer program comprising receiving at an execution unit a set of state variables which define an entry state, wherein one of the state variables defines a sequence of loop options; recording the entry state in a storage unit; in the execution unit, executing a first loop option in the ordered sequence of loop options in the entry state, using as parameters at least one of the other state variables in the set of state variables, wherein executing the first loop option comprises cancelling the first loop option from the ordered sequence, carrying out processing steps using at least one state variable, and determining if any of the state variables have altered as a result of the processing steps, wherein if none of the state variables have altered, entering a next loop iteration with an entry state in which the first loop option is cancelled from the ordered sequence, revealing a new first loop option, and; if at least one of the state variables has altered, reinstating the cancel

Abstract: Computer implemented methods include querying a traffic forwarding table at a device in a computer network, the traffic forwarding table having entries which are accessible using a key. The methods further include identifying a forwarding address for use in querying the traffic forwarding table, where the forwarding address constitutes only part of a key and where a remaining part of the key is an embedded index in the traffic forwarding table. The methods additionally include combining the forwarding address with a plurality of embedded indices of the traffic forwarding table to generate a set of keys for querying the traffic forwarding table; and generating a query message for the forwarding table using at least one of the set of keys.

Abstract: The invention relates to a computer implemented method of identifying in a network of interconnected devices a path through the network from a source device to a final destination device, the path comprising a connected sequence of devices, the method comprising at a monitor computer connected to the network: identifying a first device connected to the source device; transmitting a first query to the first device, the query including a destination identifier and requesting identification of an egress port for messages addressed to the destination identified by the destination identifier when the query is received at the first device; receiving a result message identifying the egress port and identifying the second device connected to the first device based on a network topology accessible by the monitor computer; and addressing a next query to the second device and receiving a next result message identifying an egress port from the second device; and identifying from the network topology a third device connec

Abstract: The invention relates to a computer implemented method of querying a traffic forwarding table at a device in a computer network, the traffic forwarding table having entries which are accessible using a key, the method comprising: identifying a forwarding address for use in querying the traffic forwarding table, wherein the forwarding address constitutes only part of a key and wherein a remaining part of the key is an embedded index in the traffic forwarding table; combining the forwarding address with a plurality of embedded indices of the traffic forwarding table to generate a set of keys for querying the traffic forwarding table; and generating a query message for the forwarding table using at least one of said set of keys.

Abstract: The invention relates to a computer implemented method of identifying an egress port of a focus device connected in a computer network, the method being implemented at a monitor computer connected to the network and comprising: generating a query message to the focus device, the query message including an address identifying the device and a query key formulated based on a destination identifier, and including an instruction readable at the device to return the result message including identification of an egress port for messages addressed to the destination identified in the destination identifier when the query message is received at the device; receiving a result message at the monitor computer; reading the result message, and where the result message does not identify an egress port autonomously generating at least one subsequent query message; including at least one of (i) a different address for a different device connected in the computer network, and (ii) a different query key, selected by the monito

Abstract: The invention relates to a computer implemented method of identifying a next hop from a focus device in a path of interconnected devices including switching and routing devices, wherein a switching device operates according to a switching address protocol and a routing device operates according to a routing address protocol, the method implemented at a management computer having a query path to the interconnected devices and comprising: for a focus device which is configured to receive traffic addressed to a terminal destination and to act as a routing device for the traffic, dispatching a query message containing a query key based on a destination identifier for the terminal destination from the management computer to the focus device to identify the next routing address for traffic addressed to the terminal destination; receiving a result message containing a new routing address which is the next routing address; and ascertaining from the new routing address the corresponding switching address which is the

Abstract: The invention relates to a computer implemented method of identifying in a network of interconnected devices a path through the network from a source device to a final destination device, the path comprising a connected sequence of devices, the method comprising at a monitor computer connected to the network: identifying a first device connected to the source device; transmitting a first query to the first device, the query including a destination identifier and requesting identification of an egress port for messages addressed to the destination identified by the destination identifier when the query is received at the first device; receiving a result message identifying the egress port and identifying the second device connected to the first device based on a network topology accessible by the monitor computer; and addressing a next query to the second device and receiving a next result message identifying an egress port from the second device; and identifying from the network topology a third device connec