Abstract: 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.

Abstract: A method and apparatus for changing a packet tag status value from a first value to a different value upon said packet arriving at a buffer if there already is a packet in the buffer queue having the same first status value. A sequence of tag status values (112) in packets received at an end node is used to determine the queue length of the buffer in the packet network. An end node can thereafter adapt its sending rate to the rate of the buffer.

Abstract: Disclosed is a method and apparatus for a packet data flow to use markings on packets (93, 94) that indicate the longest instantaneous queue length on a path in order to rapidly increase the flow rate up to an available capacity of a network node without overshoot, in order to avoid the TCP Slow start process.

Abstract: Methods and apparatus are disclosed for signalling congestion being caused by data items such as packets, received at a network element such as a router, in a communications network such as the Internet, or being caused by items otherwise requiring service or capacity from a shared resource. Preferred embodiments of the method involve identifying whether or not received data items received at a network element are capable of carrying congestion indications such as ECN marks, and for those that are capable, assigning congestion indications to the data items in dependence on a queue length characterization based on a substantially current, instantaneous measurement of the length of the queue, whereas for those that are not capable, a sanction such as dropping may be applied in dependence on a different queue length characterization based on a weighted moving average of current, recent, and less recent measurements of the length of the queue.

Abstract: Methods and apparatus are disclosed for obtaining and processing information from a predetermined portion of a header of a data item such as an IP packet transmitted via a communication network such as a packet network, the portion carrying a codepoint selected from a first set of codepoints each of which has a pre-defined meaning according to a first pre-defined communication protocol.

Abstract: Disclosed is a method and apparatus for a packet data flow to use markings on packets (93, 94) that indicate the longest instantaneous queue length on a path in order to rapidly increase the flow rate up to an available capacity of a network node without overshoot, in order to avoid the TCP Slow start process.

Abstract: A method and apparatus for changing a packet tag status value from a first value to a different value upon said packet arriving at a buffer if there already is a packet in the buffer queue having the same first status value. A sequence of tag status values (112) in packets received at an end node is used to determine the queue length of the buffer in the packet network. An end node can thereafter adapt its sending rate to the rate of the buffer.

Abstract: Methods and apparatus for signalling congestion are described, in respect of a network element (10) operable to forward received data items in a telecommunications networks such as the Internet, and in respect of a processing element operable to process received requests for service. In either case, the element is operable to perform its processing function at up to a processing rate which is subject to variation, and has a queue for items awaiting processing having a counter associated therewith which maintains a count from which a queue metric is derivable. The method comprises: updating the count at a rate dependent on the processing rate (32, 50); further updating the count in response to receipt of items awaiting processing (32, 50); and signalling a measure of congestion in respect of the element in dependence on the queue metric (34, 36, 50).

Abstract: Methods and an associated traffic management module and system are disclosed for monitoring, at a traffic management module (26) within a data network, path characterisation information indicative of at least one measure of a dynamic network characteristic at a remote node (23) outside said data network. The method involves a traffic management module (26) receiving at least one data unit from a remote node (23) 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.

Abstract: Methods and apparatus are disclosed for obtaining information from one or more headers of a data item transmitted via a communication network, a predetermined portion of at least one header carrying a symbol or combination of symbols having a first pre-defined meaning according to a first pre-defined communication protocol. The method comprises inspecting at least one header of a received data item whereby to identify the symbol or combination of symbols carried by the predetermined portion thereof; identifying whether at least one other portion of a header of the data item is carrying the same symbol or combination of symbols; and in the event that it is identified that at least one other portion of a header of the data item is carrying the same symbol or combination of symbols, ‘interpreting and/or processing at least one of the one or more headers according to a second pre-defined communication protocol, the second communication protocol differing from the first communication protocol.

Abstract: Methods and apparatus are disclosed for signalling congestion being caused by data items such as packets, received at a network element such as a router, in a communications network such as the Internet, or being caused by items otherwise requiring service or capacity from a shared resource. Preferred embodiments of the method involve identifying whether or not received data items received at a network element are capable of carrying congestion indications such as ECN marks, and for those that are capable, assigning congestion indications to the data items in dependence on a queue length characterisation based on a substantially current, instantaneous measurement of the length of the queue, whereas for those that are not capable, a sanction such as dropping may be applied in dependence on a different queue length characterisation based on a weighted moving average of current, recent, and less recent measurements of the length of the queue.

Abstract: Methods and apparatus are disclosed for obtaining information from one or more headers of a data item transmitted via a communication network, a predetermined portion of at least one header carrying a symbol or combination of symbols having a first pre-defined meaning according to a first pre-defined communication protocol. The method comprises inspecting at least one header of a received data item whereby to identify the symbol or combination of symbols carried by the predetermined portion thereof; identifying whether at least one other portion of a header of the data item is carrying the same symbol or combination of symbols; and in the event that it is identified that at least one other portion of a header of the data item is carrying the same symbol or combination of symbols, ‘interpreting and/or processing at least one of the one or more headers according to a second pre-defined communication protocol, the second communication protocol differing from the first communication protocol.

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

Abstract: Methods and apparatus are disclosed for obtaining information from a predetermined portion of a header of a data item such as an IP packet transmitted via a communication network such as a packet network, the portion carrying a codepoint selected from a first set of codepoints each of which has a pre-defined meaning according to a first pre-defined communication protocol. The method comprises: receiving the data item (s71); inspecting the header whereby to determine the codepoint carried by the predetermined portion thereof (s72); identifying whether the codepoint is a member of a second set of codepoints (s77, s78), the second set comprising fewer possible codepoints than the first set; and in the event that the codepoint is identified as being a member of the second set, and in dependence on such an identification being made, interpreting that codepoint according to a different pre-defined communication protocol as having a different pre-defined meaning (s80).

Abstract: Methods and an associated traffic management module and system are disclosed for monitoring, at a traffic management module (26) within a data network, path characterisation information indicative of at least one measure of a dynamic network characteristic at a remote node (23) outside said data network. The method involves a traffic management module (26) receiving at least one data unit from a remote node (23) 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.

Abstract: In a data distribution system, data is divided into a number of application data units. A sequence of keys is generated systematically, and a different key is used to encrypt each data unit at the source. At the receivers, corresponding keys are generated and used to decrypt the data units to gain access to the data. The constructions used to generate the keys are such that an intrinsically limited subset of the entire sequence of keys is made available to the user by communicating a selected combination of one or more seed values.

Abstract: A packet network is arranged into a hierarchy, having one organization-level portion (CS, P, R2) and three site-level portions (S1, S2, S3). By using forwarding computers and assigning multicast addresses in respect of each portion, the total number of multicast addresses required to send multicast messages to all possible subsets of potential recipients is reduced. This alleviates routers in the network of the burden associated with storing and processing a large amount of multicast addresses.

Abstract: In a data distribution system, data is divided into a number of application data units. A sequence of keys is generated systematically, and a different key is used to encrypt each data unit at the source. At the receivers, corresponding keys are generated and used to decrypt the data units to gain access to the data. The constructions used to generate the keys are such that an intrinsically limited subset of the entire sequence of keys is made available to the user by communicating a selected combination of one or more seed values.