Abstract: A system and method for estimation of round trip times (RTTs) within a TCP based data network is described. The system provides for a passive monitoring of the network round-trip latency by simply observing existing TCP connections in operation. In this way, it is possible to measure RTT out to a remote site without having to send any traffic to that site with the result that there is no impact on the network, and it is possible to estimate what production traffic is experiencing.

Abstract: Embodiments of the invention relates to bandwidth requirements within a packet data network. A method and system for analysing traffic is described herein. The method may utilises an estimation of a concave hull function of the arrived traffic within the buffer. The use of such a concave hull representation may allows for more efficient data processing and for a direct measurement of desired service rates for differing predetermined control parameters.

Abstract: A methodology and network tool for evaluating one-way directional delays in a packet network is described. The invention provides for a discrimination of the directional components of the delay experienced by packets travelling between nodes in a network. This identification of the directional delay component assists in an understanding of network behaviour and can be represented on a graphical user interface. Such methodologies are achieved without requiring clock synchronisation between clocks at each of the nodes.

Abstract: A methodology and network tool for evaluating one-way directional delays in a packet network is described. The invention provides for a discrimination of the directional components of the delay experienced by packets travelling between nodes in a network. This identification of the directional delay component assists in an understanding of network behaviour and can be represented on a graphical user interface. Such methodologies are achieved without requiring clock synchronisation between clocks at each of the nodes.

Abstract: A data network in which at least one switch is provided with the facility for estimating current network demands using a polygonal approximation to scaled cumulant generating function. The approximation is iteratively refined in accordance with sampled data passing through the switch. The switch estimates the demand associated with a new data processing request as it is received by the switch and decides whether to accept the request based on available resources.

Abstract: The invention relates to a system and method for estimating the effective bandwidth on-line at a node in a communications network. The invention works by measuring the effective bandwidth and the mean rate of traffic flow for an identified type of traffic flow off-line, defining a relationship between the two measured values and storing the relationship in a database of relationships for different identifiable types of traffic flow off-line. A type of traffic flow or group of flows is identified on-line from which the mean rate of traffic flow is measured on-line which is a relatively simple measurement to make. From the database of relationships a relationship is obtained from which the effective bandwidth is estimated for the traffic flow or flows on-line.