摘要:
The present invention relates to a system and method for dynamically adjusting the bandwidth of a continuous bit rate virtual path connection established between a source node and a destination node within a packet or cell switching network comprising a plurality of nodes interconnected with transmission links. In the network, a bandwidth management server having access to information concerning network nodes and transmission links is defined. This server is informed each time a virtual path connection or a virtual channel connection is established on the network with an indication concerning the initial bandwidth reserved for said connection. The server detects and shares, on a continuous or periodical mode, the bandwidth which is available on transmission links among the bandwidth adjustable continuous bit rate virtual path connections and determines for each connection a new bandwidth. The source node is informed each time a new bandwidth is computed. It adjusts the bandwidth of the corresponding bandwidth adjustable continuous bit rate virtual path connection accordingly.
摘要:
A method for operating a node in a computer network is disclosed, where the network is made up of nodes connected by links. The method has the steps: determining an alternate path for one or more links; reserving resources for the alternate path; and rerouting traffic on the alternate path in case of a link failure. The alternate path may be periodically updated. A plurality of alternate paths may be maintained. The alternate paths may not have any links in common. User traffic may be rerouted substantially simultaneously to each link of the alternate path in the event of failure of a primary path.
摘要:
A method and system of transmitting data frames from a sending unit (10) to a receiving unit (12) in a data transmission network comprising at least a backbone (14) wherein the data are transmitted over high speed links enabling long Maximum Transmission Units (MTU) between an ingress node (18) connected to the sending unit by a first access link (16) and an egress node (22) connected to the receiving node by a second access link (20), with at least one of the first and second access links being a low speed access link requiring the data frames to be segmented into short MTUs between the sending unit and the ingress node and between the egress node and the receiving unit. A plurality of consecutive segmented data frames (28) belonging to the same flow of data transmitted from the sending unit to the ingress node are assembled by the ingress node into an assembled data frame (30) corresponding to the long MTU, the assembled data frame is transmitted over the backbone from the ingress node to the egress node at a high speed authorized by the backbone links, and the assembled data frame is de-assembled into consecutive segmented data frames (32) corresponding to the short MTUs by the egress node before being transmitted to the receiving unit.
摘要:
A packet scheduling system for use in a switching node of a high speed packet switching network. Incoming packets are enqueued in connection queues. Each connection is classified as red (exceeding traffic profile) or green (within traffic profile). QOS priority is also identified for each connection. Packets are dequeued for transmission as a function of priority class and connection class. Higher priority class connections have priority over lower priority class connections. Within a given priority class of connections, green connections have priority over red connections. Round robin scheduling is used for packets from connections in the same priority and connection class. In addition, a dynamic priority coupling mechanism is provided to prevent red higher priority traffic from blocking green lower priority traffic.
摘要:
Adaptive bandwidth allocation for Non-Reserved traffic over high speed transmission links of a digital network is operated through regulation of data packet transfers over network nodes/ports including input/output adapters connected through a switching device. A network node is assigned with a Control Point computing devise (CP) storing a Topology Data Base containing an image of the network. This Data Base is periodically and at call set up updated by Topology Data Base Update messages (TDUs) including an Explicit Rate parameter for link l indicating the current available bandwidth on link l, and a parameter NNRl indicating the number of Non-Reserved connections on link l. This information are used within each Adapter to periodically regulate the transmission bandwidth assigned to each Non-Reserved traffic connection within the network. To that end, each adapter is provided with an Access Control Function device for each attached connection (data source) and a Connection Agent (CA) getting, on request, required current link informations from the attached Topology Data Base.
摘要:
A method and an apparatus implementing a shaping function in a fixed length cell switching network node adapter supporting output lines in a telecommunication network. The adapter includes a Time Division Multiplexing (TDM) table where each entry is a pointer to a first cell of a queue of cells stored in the adapter for a given traffic. When a new traffic is established, the TDM table is updated. A placement device performs the pre-computation of the best placement of the entries reserved for one traffic in the TDM table. The placement device minimizes the Cell Delay Variation as computed by a Generic Cell Rate Algorithm (GCRA--ITU standard organization) policer. The Cell Delay Variation (CDV) is defined as the deviation of the placement of the cells from their ideal position in an output stream, the ideal placement being when the cells are spaced with an interval corresponding to the period of traffic negotiated at traffic establishment time. The preferred embodiment includes a scheduler which reads the TDM table and fetches the corresponding cell in the queue storage to send the cell onto the output line via a line interface unit.
摘要:
A method and system of transmitting data frames from a sending unit (10) to a receiving unit (12) in a data transmission network comprising at least a backbone (14) wherein the data are transmitted over high speed links enabling long Maximum Transmission Units (MTU) between an ingress node (18) connected to the sending unit by a first access link (16) and an egress node (22) connected to the receiving node by a second access link (20), with at least one of the first and second access links being a low speed access link requiring the data frames to be segmented into short MTUs between the sending unit and the ingress node and between the egress node and the receiving unit. A plurality of consecutive segmented data frames (28) belonging to the same flow of data transmitted from the sending unit to the ingress node are assembled by the ingress node into an assembled data frame (30) corresponding to the long MTU, the assembled data frame is transmitted over the backbone from the ingress node to the egress node at a high speed authorized by the backbone links, and the assembled data frame is de-assembled into consecutive segmented data frames (32) corresponding to the short MTUs by the egress node before being transmitted to the receiving unit.
摘要:
A method and a system of network capacity planning for use in a high speed packet switching network. The network comprises a plurality of switching nodes interconnected through a plurality of communication links, each of the switching nodes comprises means for switching packets from at least one input link to at least one output link. Each of the output links is coupled to at least one buffer in the switching node for queuing packets before they are transmitted over the output link. In each of the switching nodes and for each of the output links, a time distribution of the occupancy of each buffer during a predetermined monitoring time period is measured, and stored in a centralized memory location. Then, the buffer occupancy time distribution data are retrieved from the centralized memory location in all the switching nodes, gathered and stored in a network dedicated server. These buffer occupancy time distribution data for all the nodes are transmitted from the dedicated network server to a network monitoring center. In the network monitoring center, the buffer occupancy time distribution data are integrated on a larger time scale, and stored. Finally, the integrated buffer occupancy time distribution data are used to apply network capacity planning actions to the network resources.
摘要:
An apparatus and method that determines the end-to-end transit delay at each node of a path, in accordance with the selected probability value indicative of the probability to experience a delay at each node that is smaller than the computed transit delay. Then the computed transit delays per nodes are combined to obtain the end-to-end delay of the path, the combination being either an arithmetic operation or a convolution operation. A method to approximate the convolution operation is also disclosed.
摘要:
A system and method of providing to an Asynchronous Transfer Mode (ATM) access network a standard ATM interface for accessing a non standard ATM bandwidth adjustable virtual path connection established on a backbone network between a backbone source node and a backbone destination node. A standard ATM available bit rate (ABR) virtual path connection is established between the ATM access network and the backbone source node of the bandwidth adjustable virtual path connection. The available bit rate of this ABR virtual path connection is adjusted according to the adjusted bandwidth of the virtual path connection establish on the backbone node.