International Business Machines Corporation

Ralph Benjamin Case

Roy Frank Brabson

Brad Byer Topol

Wesley McMillan Devine

Brad Alan Makrucki

Patrick Gerald Brown

Raymond F Bird

Samuel E Reynolds

Johnathan L Harter

James John Martin

An improved technique is disclosed for routing data across multiple topology subnets, and for improving the connectivity between nodes in multiple topology subnets, by using a common connection network. A new type of virtual node, referred to herein as a 'global' virtual routing node or 'GVRN', is defined to represent connectivity to an underlying network that may extend beyond the boundaries of the topology subnets in the end-to-end path. This underlying network is also referred to as a &#x201c;common connection network&#x201d; or a &#x201c;global connection network&#x201d;. The present invention also defines novel techniques with which border nodes pass routing information between networks to convey connectivity to the GVRN. In many cases, use of GVRNs will result in shorter end-to-end data transmission paths.

Efficient connectivity between multiple topology subnets via common connection network

A technique for adapting receiver thresholds to improve rate-based flow control in a data communications network. With this invention, the flow control process becomes self-calibrating such that threshold values are dynamically adjusted to adapt to current network conditions, without requiring user intervention. Several different indicators of network conditions are monitored, and appropriate adjustments are made to the threshold(s) upon detecting these specific indicators. One monitor enables the threshold to increase when the network is uncongested, enabling the sender to increase its transmission rate. Conversely, the threshold is lowered if the network is congested, so that the transmission rate will be decreased. Another monitor balances bandwidth allocation among connections sharing a bottleneck resource, by lowering the threshold (and therefore decreasing the send rate) when a connection uses a high share of the resource. A third monitor detects the presence of traffic from protocols not using adaptive receiver thresholds, and adjusts the threshold (including an upper and lower threshold bound) in order to compete fairly for resources with these other protocols. The monitors may be implemented individually or in combination.

Adapting receiver thresholds to improve rate-based flow control

A method, system, and computer-readable code for measuring network latency between a client computer and a server machine without requiring any additional software on the client. Network latency is a measurement that reflects the network round trip delay between a client machine and a server machine. The present invention defines a novel technique for gathering latency information. This information may be used in a variety of ways (such as making policy decisions that may limit the amount of data sent over a communications path due to detection of high latency in the network).

Technique for measuring round-trip latency to computing devices requiring no client-side proxy presence

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Raleigh, NC, United States of America

Ralph Benjamin Case