British Telecommunications Public Limited Company

British Telecommunications Corporation

Arnaud Jacquet

Robert J Briscoe

Andrea Soppera

Tobias Moncaster

Alan P Smith

Alessandro Salvatori

Stephen Clifford Appleby

Trevor Burbridge

Carla Di Cairano-Gilfedder

Sebastien Cazalet

Robert John Briscoe

Peter Hovell

Bob Briscoe

Toby Moncaster

C Di Cairano-Gilfedder

David J Songhurst

David John Songhurst

Alan Philip Smith

A method of attributing contributions to congestion of a shared resource to respective user registers, the resource being operable to serve requests for service, each of a plurality of the requests having a user indication associated therewith indicating with which of a plurality of user registers the request is associated.

Attribution of congestion contributions

Apparatus and methods for policing flows of data units () along a path in a data network in dependence on congestion indications associated with said data units indicating whether or not said data units have experienced, or are expected to experience, congestion on the path, said apparatus and methods allowing for a high but not unlimited short-term burst rate (w) of data units having congestion indications associated therewith, the short-term burst rate being high when compared with a long-term average rate (w) at which data units having congestion indications associated therewith may be forwarded without the data units being subjected to a policing action such as dropping, delaying or marking for possible sanction.

Policing in data networks

Methods and apparatus for providing path characterization information relating to a network characteristic such as network congestion to nodes in a data network using data units being forwarded from a source to a destination via a plurality of nodes in the network, the method comprising: receiving, at a first proxy node, data units from a source, each data unit comprising a destination indication indicative of an intended destination; identifying, in respect of an intended destination indicated, a second proxy node in the network to which data units may be forwarded before being forwarded to the intended destination; and forwarding a first and at least one subsequent data unit from the first to the second proxy node via 'one or more intermediate nodes; the method further comprising assigning conditions to path characterization metrics in respect of data units traversing a path across the network from the first to the second proxy node, the initial condition being dependent on information received by the first from the second proxy node.

Path characterisation in networks

Methods and an associated traffic management module and system are disclosed for monitoring, at a traffic management module () within a data network, path characterisation information indicative of at least one measure of a dynamic network characteristic at a remote node () outside said data network. The method involves a traffic management module () receiving at least one data unit from a remote node () outside said data network, and in the event that said at least one data unit is encapsulated in an outer header and that an inner header of said data unit includes path characterisation information, performing the following in respect of said data unit: (a) monitoring said path characterisation information in said inner header; and (b) forwarding said data unit according to a first treatment category. In the event that these conditions are not met, the data unit is instead subjected to an alternative treatment.

Monitoring path characterisation information

Methods and systems for policing usage by one or more users () of a data network (), said one or more users () being able to send, to receive, or to send and receive data over the network via one or more of a plurality of access nodes (), the usage of the data network resulting from respective data units consuming network resources along respective paths across the data network (), each of said data units being associated with one of a plurality of subsets of the usage of the data network, said data units having congestion indications associated therewith indicating a measure of their congestion impact.

Policing usage of data networks

Methods and systems for assigning information indicative of a network characteristic to one of a plurality of data units traversing a path across a network, said data units having associated therewith values indicative of said network characteristic, said path having at least one portion passing through a lower-capability region and at least one portion passing through a higher-capability region, said lower-capability region being a region in which information indicative of said network characteristic may be represented by values having a first resolution, and said higher-capability region being a region in which information indicative of said network characteristic may be represented by values having a second resolution, said second resolution being greater than said first resolution, said one data unit being a data unit entering said higher-capability region.

Network characterisation

Data networks, nodes making up parts of data networks, and information are related to the characterization of paths taken by data travelling between nodes in the networks. Path characterization information is arranged to be conveyed to nodes such that it may be used by nodes subsequently forwarding data. In particular, the invention relates to nodes receiving such path characterization information from upstream nodes, deriving therefrom information indicative of characteristics of a path downstream of said nodes, and using such information to make informed decisions such as routing decisions when forwarding data onward in data networks.

Treatment of data in networks

Path characterization information is provided to a data sender relating to a network characteristic such as congestion experienced by data units traversing a path across a data network from the data sender towards one of a plurality of data receivers. The data units have associated therewith information indicative of the network characteristic. The path is traversed by the data units having at least a first path portion between the data sender and a proxy node along which data units may traverse conveying a measure indicative of the network characteristic that is representable by any of a first set of codepoints. The data receivers are operable to provide data acknowledgement units in respect of data units they receive via a second path portion in which information indicative of the network characteristic may only be representable using codepoints of a second set of codepoints having less codepoints than the first set.

Provision of path characterization information in networks

Methods and apparatus for encoding a number of small dynamic values over an n-bit field. Also methods and apparatus allowing for the stateless extraction of separate sequences from repetitions of a single field whereby to communicate more than one signal at once.

Control of data in a network

Data networks and nodes making up parts of data networks are arranged to derive information relating to the characterization of paths taken by data travelling between nodes in the networks. Path characterization information is fed back from a receiver of data to a provider of data, and informs nodes subsequently forwarding data of characteristics of the downstream path. Also described are routing and related controlling nodes and methods for using such path characterization information to make informed routing and other decisions when forwarding data in a data network.

Networks

Methods and systems for determining origin-specific network metrics in respect of a data network having at least one ingress node, the method comprising: receiving data items from outside the network; forwarding the data items with headers comprising fields for carrying origin information relating to the origin of the data item, and path metric information indicative of a characteristic being monitored; causing the data items to traverse the network; updating the fields carrying path metric information as the data items traverse the network; determining the origin information and path metric information after the data items have traversed the network and deriving in dependence thereon an origin-specific path metric relating to the characteristic in respect of the relevant portion of a path across the network; and combining origin-specific path metrics derived in respect of different data items if they relate to characteristics in respect of data items having a common origin. Also, methods and systems for determining target-specific network metrics in respect of a data network having at least one egress node.

Measuring network metrics

Methods and systems for determining a correction factor for use in monitoring network traffic, said network traffic comprising a plurality of flows of data units, each flow having associated therewith a flow identifier, said data units having associated therewith a path characterization metric; the method comprising the steps of: selecting a subset of flow identifiers from the overall set of flow identifiers; determining, in respect of flows having associated therewith flow identifiers from said selected subset of flow identifiers, which flows if any are persistently irregular flows; determining a first measure of the total of the accumulated path characterization metrics associated with data units of said selected subset of flows; determining a second measure indicative of the proportion of said total measure contributed by said persistently irregular flows; and determining a correction factor in dependence on the first and second measures.

Monitoring networks

Flow in a data network is policed by determining a measure of greediness of a flow through a node, comparing the measure of greediness with a measure indicative of acceptable greediness dependent on the expected greediness of a compliant flow experiencing substantially similar path conditions, and designating the flow for possible sanction in the event that the greediness is not in accordance with the acceptable greediness. Such allows for the policing of a data network when one or more fields in a data packet that carry information relating to a characterization of an end-to-end path and/or a downstream path of the data packet are used in order to police the data network.

Policing networks

A processing node for processing data items in a data network, comprising means for receiving data items, means for receiving characterization metrics associated with the data items and identifying characteristic values in respect thereof, and a process selection means, said process selection means comprising means for deriving a collective value from characteristic values associated with a plurality of the data items, means for comparing characteristic values associated with a plurality of the data items with a predetermined target value, means for subjecting data items in respect of which the characteristic values are on a first side of the predetermined target value to a first process, means for selecting at least some of the data items in respect of which the characteristic values are on a second side of the predetermined target value, and means for subjecting the selected data items to a second process which is different from the first process.

Processing of data in networks

Packet forwarding apparatus has an input for receiving packets; a packet classifier arranged in operation to read a class indication in received packets and in dependence thereon to pass packets to a class-based policer associated with the class indicated; a plurality of class-based policers, each operable to assign a provisional indication to packets of the associated class in response to a measure of the load presented by packets of the class exceeding a predetermined class-based threshold; a multi-class policer operable to receive provisionally-indicated packets processed by the class-based policers, and to assign a congestion indication to packets having the provisional indication in response to congestion arising at the packet forwarding apparatus; and an output for presenting packets processed by the multi-class policer for onward transmission from the apparatus.

Growing community of inventors

Ipswich, United Kingdom

Arnaud Jacquet