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AssigneeNortel Networks Limited
InventorsQingwen Hu, Michael L. Aalders, Darek R. Skalecki
Estimating the term…
Dynamic adaptation of connection-oriented networks is introduced wherein, once congestion is encountered, dynamic adaptation steps may be performed. Four adaptation steps are proposed for reacting to various network congestion scenarios. It is further recommended that the steps are performed in a particular order such that the higher severity and longer sustentation of the network congestion the more strict step is performed to alleviate the network congestion. At a switch in the connection-oriented network, utilization of a trunk carried on a link connected to the switch is monitored and, if said utilization of said trunk exceeds a first threshold, a first degree of adaptation is initialized wherein use of the trunk by further connections is prevented. Subsequent degrees of adaptation are triggered when high utilization continues and surpasses higher thresholds. The subsequent degrees of adaptation involve rerouting connections that make use of the trunk.
A method of adaptively routing connections through a connection-oriented data network, said connection-oriented data network including a plurality of switches and a plurality of links connecting said plurality of switches, said method comprising:
A path administrator in a switch in a connection-oriented data network, said path administrator operable to:
A path administrator in a switch in a connection-oriented data network, said path administrator comprising:
A computer readable medium containing computer-executable instructions which, when performed by a processor in a switch in a connection-oriented data network, cause the processor to:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
In networks: network management
Topology update or discovery: routing in connection-oriented networks, e.g. X.25 or ATM
Routing or path finding of packets in data switching networks: alternate routing
Arrangements for interconnection between switching centres: trunk circuits
Term ended 17 Mar 2022 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
The present invention relates to connection-oriented networks and, more particularly, to dynamic adaptation to congestion in such networks.
Increasingly, products are available to network service providers and enterprises alike that provide for and optimize the delivery of a variety of services including voice, data and video across wide area networks. In many instances, these wide area networks are connection-oriented, that is, a request is received for a connection through the network and a path is selected and established responsive to that request. Connection-oriented networks include many switches inter-connected by links, where each link may be provisioned to carry one or more trunks, where a trunk is for carrying a voice or data channel between switches. Unfortunately, network congestion can occur when a number of channels are routed through paths that use the same trunk. Alternatively, an entire network may become congested when all trunks are being utilized for connections.
Connection-oriented networks are particularly well suited to path-oriented traffic (switched voice, permanent voice, video, etc.) but connectionless data may also be carried on the same trunks. Although these networks may carry both voice and data traffic, a customer of a network service provider may consider that one type of traffic should have priority over the other. For example, the customer may wish to prevent or bump voice traffic from a particular trunk in preference to data traffic during times of congestion or high utilization. Voice connections that have been prevented access to, or bumped from, the particular trunk may be rerouted, if possible, through other trunks or over the Public Switched Telephone network (PSTN).
In the figures which illustrate example embodiments of this invention:
FIG. 1 schematically illustrates a communication system for use with an embodiment of the present invention;
FIG. 2 schematically illustrates a switch suitable for use with an embodiment of the present invention;
FIG. 1 illustrates a communication system 100 that includes a connection-oriented data network 102 including a number of switches 106V, 106W, 106X, 106Y, 106Z connected by a number of links 108 (also referred to as an individual link 108). The links 108 may be provisioned to carry trunks. The connection-oriented data network 102 may be used to connect a local private branch exchange telephone system (PBX) 110A to remote PBX 110B thereby facilitating a voice connection between a local telephone station apparatus 114A and a remote telephone station apparatus 114B. Alternatively, the local PBX 110A may connect to the remote PBX 110B via a public switched telephone network (PSTN) 112. The connection-oriented data network 102 may carry many types of data traffic including, Asynchronous Transfer Mode (ATM) traffic, frame relay traffic, Multi-Protocol Label Switched (MPLS) traffic, Internet Protocol (IP) traffic, etc.
A network exemplary of the connection-oriented data network 102 would employ a connection-oriented routing system for selecting, establishing and managing connections for various services. The routing system may be based on a centralized scheme, a distributed scheme or a hybrid of the two schemes. Responsive to a connection request, a network using the routing system selects a route through the network from a source to a destination (specified in the connection request), establishes a path along that route and then manages the path. In particular, a path management function of the routing system provides switches in the network with capabilities to respond to facility (link, switch or hardware) failures or preemption along the established path by rerouting the path to another route. Further included in the path management function are capabilities to monitor the path to determine whether the path can be rerouted to a more optimal route. Once a path is established by the routing system, the services may start using it for data transfer.
Connection-oriented routing systems fitting the above description are described in: ATM Forum Technical Committee, “Private Network-Network Interface Specification Version 1.0 (PNNI 1.0),” af-pnni-0055.000, March 1996; R. Callon, et al, “A Framework for Multiprotocol Label Switching”, Work in Progress, November 1997; E. Rosen, et al, “Multiprotocol Label Switching Architecture”, Work in Progress, July 1998; Bilel Jamoussi, “Constraint-Based LSP Setup using LDP,” draft-ietf-mpls-cr-ldp-03.txt, Work in progress, September 1999; and Awduche, et al, “RSVP-TE: Extensions to RSVP for LSP Tunnels,” draft-ietf-mpls-rsvp-lsp-tunnel-05.txt Network Working Group, Internet Draft, all of which are hereby incorporated herein by reference.