摘要:
The traffic congestion in the switch of a network node made to switch data packets of different priorities from input lines, via receive adapters, to output lines via transmit adapters, is taken care of by using a so-called spacing function whereby the data transfers through the switch are operated at a predefined limited switch speed, said spacing function being overriden whenever high priority traffic occurs or in case of a backpressure signal being generated by the switch to indicate switch operation congestion conditions.
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:
An method and an apparatus implementing a shaping function in a fixed length cell switching network node (5) adapter supporting output lines (25); the invention uses a Time Division Multiplexing (TDM) table (270) where each entry is a pointer to a the first cell of a queue (240) of cells of a given traffic; When a new traffic is established, the TDM table is updated; placement device (250) performs the pre-computation of the best placement of the entries reserved for one traffic in the TDM table (270) minimizing the Cell Delay Variation as computed by the GCRA policer (ITU standard organization). The Cell Delay Variation (CDV) defined as the deviation of the placement of the cells in the output stream from their ideal position which is when the entries are spaced with an interval corresponding to the period of traffic negociated at traffic establishment time. The preferred embodiments includes a scheduler (280) able to read the TDM table and to fetch the corresponding cell in the storage (230) to send it onto the output line via the line interface adapter.
摘要:
Disclosed herein is a connection bandwidth management process and system 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 are coupled to at least one buffer in the switching node for queuing packets before they are transmitted over the output link. Each of the communication links supports the traffic of a plurality of user connections statistically multiplexed over the link. Each user connection is allocated an initial agreed-upon bandwidth through the network, with each of the communication links being possibly oversubscribed. The connection bandwidth management process according to the invention comprises the steps of: Link monitoring data on the communication links are periodically received in a network monitoring center, and stored in a computer memory in the network monitoring center. Then, one monitored link is selected and the corresponding link monitoring data are retrieved from the computer memory. The link monitored data retrieved for the selected link is analyzed, and it is determined whether the selected link is oversubscribed or not. If it is determined that the selected link is oversubscribed and that the link monitoring data for the selected link satisfies at least one predetermined condition the bandwidth initially allocated to each of the connections boarded on the selected link is reallocated, such that, the sum of the reallocated bandwidth of the connections boarded on the selected link is less or equal to the total bandwidth capacity of the selected link. The process recycles until all the monitored links have been selected.
摘要:
Disclosed herein is 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. The network capacity planning method of the invention comprises the following steps: 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 improved access control system for a common or global data storage supporting virtual output queues dedicated to each of the output lines of the storage is described for data of different priorities. The improvement consisting in having thresholds for each priority class with respect to the global occupation level of the storage and to the occupation level of each virtual queue. The new access control system enables a contention control. It further includes the generation of a backpressure signal for the data transmitting input as to indicate the success of the transmission. This signal can be reduced to a single bit irrespective of the number of thresholds and priority classes.
摘要:
The present invention relates to a method and system for optimizing the end to end path selection in very large packet switching networks.The network is divided in a backbone subnetwork and a plurality of access subnetworks. These subnetworks have a certain hierarchy, but direct links between access subnetworks are allowed. To fulfil the path request between nodes not pertaining to the same subnetwork, the path selection is performed in the backbone subnetwork by concatenating the backbone subnetwork topology with the access subnetwork topologies where the source or destination nodes are located. Only the required subset within access subnetwork topologies is transferred and cached into the backbone subnetwork topology. The main advantages are that :
The path is computed in one step only There is no retry because there is no summarization. The computation is faster because applied on a subset of the overall topology (the backbone subnetwork plus at most two access subnetworks).
摘要:
The present invention relates to a method and system of locating a network resource in a packet switching network divided in a backbone subnetwork connected to one or a plurality of access subnetworks. The access subnetworks comprise one or a plurality of access border nodes directly connected to the backbone subnetwork. The backbone subnetwork comprises one or a plurality of backbone border nodes directly connected to the access subnetworks. Border nodes of different subnetworks are connected by border links. The method in access border nodes involves the steps of :
receiving a query message comprising a resource name, the resource name including a prefix; comparing the resource name prefix with the prefixes stored in an access border node directory database, said access border node directory database comprising prefixes of the resources local to the access border node subnetwork; determining whether the resource name relates to a resource which is local to the access border node subnetwork or not; forwarding said query message to an adjacent backbone border node when the resource name relates to a resource which is not local to the access border node subnetwork.
The method in backbone border nodes involves the steps of :
receiving a query message comprising a resource name, the resource name including a prefix; comparing the resource name prefix with the prefixes stored in one or a plurality of backbone border node directory databases. Each backbone border node directory database corresponds to an access subnetwork managed by the backbone border node; determining whether the resource name relates to a resource which belongs to an access subnetwork that the backbone border node manages or not; forwarding the query message to an adjacent access border node when the resource name relates to a resource which belongs to an access border node subnetwork managed by the backbone border.
Each access subnetwork has its own spanning tree and distributed topology, and interactions between access networks are limited to a minimum. The size of distributed topologies is kept small and the control traffic is mostly limited to subnetworks.