Bandwidth seizing in integrated services networks

A method of multimedia information communication between subscribers associated with a pair of nodes of a fast packet switched network to provide traffic flow control in the network, said nodes being connected by an end-to-end network path having multiple transmission links, and wherein the multimedia information includes a plurality of traffic component types from among voice, video and data to be communicated between subscribers associated with said nodes, said method comprising:

• launching a succession of composite frames conveying multimedia information from subscribers at one of said nodes intended for subscribers associated with the other of said nodes onto said network path, in which each of said composite frames has a plurality of channels of different fixed sizes to accommodate the traffic component types and representing differing bandwidth requirements allocated for respective ones of said traffic component types within each composite frame,
• assigning each of said traffic component types a level of priority for transmission through the network which may differ from priority levels assigned to other traffic component types, before commencing the frame launching, and
• reallocating bandwidth within newly launched composite frames according to the priority levels of said traffic component types to allocate additional bandwidth for advancing the transmission of the traffic component types having higher priority assignments across the network path while concomitantly reducing bandwidth and deferring transmission of the traffic component types having lower priority assignments across the network path during periods of traffic congestion on any of the transmission links of said network path.

A system for transmitting information during call connections between a multiplicity of subscribers as components of traffic in an integrated services network (ISN), in which the information traffic consists of a multiplicity of media types according to the requirements of the different subscribers including voice, video and data traffic component types, comprising:

• assembling means for assembling a plurality of traffic component types in separate respective subscriber information streams to be launched for transmission at an entry node of said ISN during respective call connections, into the message information payload field of each of a sequence of composite frames of variable bandwidth to occupy channels of predetermined limited bandwidth within the respective frame for transmission through the ISN, the assembling means including:
• selecting means responsive to the respective information streams for limiting the assembly of traffic component types into each composite frame to those in information streams addressed to subscribers at a common exit node of the ISN, and
• allocating means for configuring each composite frame so that the information streams of the different traffic component types are assembled into respective separate groups of channels of predetermined fixed bandwidth different from the fixed bandwidth of channels of groups associated with others of the traffic component types;
• and
• bandwidth appropriation means located at a transit node on a communications path of the ISN between the entry and exit nodes for response to traffic congestion on said path to initiate selectively seizing of bandwidth from channels of one group for expanding channels of another group associated with a traffic component type of preferred priority of transmission within each composite frame to be launched from the entry node, to control traffic flow on said path.

A method of enhancing the bandwidth of certain traffic component types transmitted by subscribers as composite information in an integrated services network (ISN), in which the subscribers are associated with nodes at endpoints of the network and the composite information traffic may include voice, video and data traffic component types transmitted in packets having a predetermined variable bandwidth allocation for each traffic component type, said method comprising the steps of

• detecting traffic congestion in the queue of packets awaiting transmission over a transmission link at a transit node on a network path between two endpoint nodes of the ISN,
• responding to a request for more bandwidth within packets to be transmitted, for a traffic component type from a subscriber associated with one of said two endpoint nodes and communicating with a subscriber associated with the other of said two endpoint nodes, in which the traffic component type for which the additional bandwidth is requested has greater priority for uninterrupted transmission through the ISN between said two endpoint nodes than other traffic component types, according to a predetermined ranking of transmission priority levels for the traffic component types supported by the ISN,
• identifying another subscriber, associated with one of said two endpoint nodes, constituting the source of a traffic component type within packets at least partly causing the congestion, of lower priority than that of the traffic component type for which more bandwidth is being requested, and
• suppressing the transmission of the lower priority traffic component type from the identified subscriber in packets emanating from the endpoint node associated with the identified subscriber, to seize bandwidth from those packets, and making the seized bandwidth in the packets emanating from that endpoint node available to the traffic component type of the subscriber for which more bandwidth is being requested.