摘要:
Virtual Private Network (VPN) dedicated to a customer using a physical transmission network based upon Multi-Protocol Label Switching (MPLS) technology including a plurality of Provider (P) devices and a plurality of Provider Edge (PE) devices, the customer owning at least two specific Customer Edge (CE) devices amongst a plurality of CE devices, a specific CE device being attached to a specific PE device and enabling the customer to gain access to any other CE device belonging to the same VPN, by the intermediary of PE devices to which are attached the CE devices. The VPN comprises several billing zones (10, 12, 14) being each defined by the application of a single flat rate. A PE device (18) belonging to each billing zone includes a virtual router (58, 60, 62) associated with each billing zone, two virtual routers being interconnected by a virtual circuit (38, 40, 42) transmitting all the traffic exchanged between the two associated billing zones so that the traffic flowing between the two billing zones can be measured and therefore precisely billed to the customer.
摘要:
A method and system for reserving a virtual connection from a source workstation to a destination workstation. Packets of data are transmitted over a network between an ingress node of the source workstation and an egress node of the destination workstation. In accordance with the method of the present invention, a reservation request is delivered from the source workstation to a reservation server. The reservation server includes a user database for storing the identification of each user allowed to access to the reservation server and also stores the rights of each user. The reservation server further includes a network database for storing the information describing a network capacity required to set up the virtual connection. A verification is then performed to determine whether or not the reservation request may be validated in view of user information within said source workstation. A second verification is performed to determine whether or not the capacity of said network is sufficient to meet the requirements of the reservation request. In response to the capacity of the network being sufficient to meet the requirements of the reservation request, a virtual connection is established from the ingress node to the egress node.
摘要:
The present invention relates to a method and system of sharing among a plurality of virtual channel connections the bandwidth of a bandwidth adjustable 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, said virtual channel connections comprising bandwidth adjustable reserved virtual channel connections with minimum bandwidth reservation and/or reserved virtual channel connections and/or non reserved virtual channel connections with minimum bandwidth reservation or/and totally non reserved connections without minimum bandwidth reservation. When the source node receives a notification indicating a new bandwidth to allocate to the bandwidth adjustable virtual path connection, and when this new bandwidth is lower than the sum of the current reserved bandwidth of virtual channel connections, the current reserved bandwidth of each bandwidth adjustable virtual channel connection is reduced by applying a ratio to the part of the current bandwidth reserved above the minimum reservation. The ratio is, in a preferred embodiment, proportional to the difference between the sum of the reserved bandwidth of all virtual channel connections and the new available bandwidth allocated to the bandwidth adjustable virtual path connection, and inversely proportional to the sum of the bandwidth reserved above the minimum reservation for the bandwidth adjustable virtual channel connections.
摘要:
This system is made to perform congestion detection and flow control in high speed digital packet switching network (22) carrying discardable and non-discardable traffic. Forward traffic received at a destination system over a first connection from a source system is monitored. If a congestion-indicating bit is detected in a received packet, a backward congestion indicator is set in packets flowing from the destination system to the source system over a second connection. The source system integrates the number of backward congestion indicators received over successive periods of time using a count-up, count-down counter. Specific congestion control actions are taken at the source system as a function of the counter state at the end of each of the successive periods of time. The congestion control actions may include increasing or decreasing the bandwidth allocated to discardable traffic intended to be delivered over the first connection.
摘要:
An explicit rate algorithm is disclosed for use in an end-to-end closed loop flow control algorithm for an ATM network which carries at least constant bit rate (CBR) traffic, variable bit rate (VBR) traffic and adjustable bit rate (ABR) traffic. The algorithm determines how much additional bandwidth is available for ABR traffic on an output link from a node and produces an explicit rate variable that can be forwarded to a source for the ABR traffic. Both the maximum and minimum bandwidths already reserved for all connections on the output link are determined. A single reserved bandwidth value is chosen within the range defined by the maximum and minimum reserved bandwidth values. The current utilization of the ABR input buffer for the node is also determined. The explicit rate variable is generated as a function of the link capacity, the reserved bandwidth value and the current utilization of the ABR input buffer. The explicit rate variable is written into a resource management cell which is routed through the network to the ABR traffic source. The explicit rate variable is intended to change the input rate of the ABR source to utilize more of the ABR input buffer.
摘要:
Virtual Private Network (VPN) dedicated to a customer using a physical transmission network based upon Multi-Protocol Label Switching (MPLS) technology including a plurality of Provider (P) devices and a plurality of Provider Edge (PE) devices, the customer owning at least two specific Customer Edge (CE) devices amongst a plurality of CE devices, a specific CE device being attached to a specific PE device and enabling the customer to gain access to any other CE device belonging to the same VPN, by the intermediary of PE devices to which are attached the CE devices. The VPN comprises several billing zones (10, 12, 14) being each defined by the application of a single flat rate. A PE device (18) belonging to each billing zone includes a virtual router (58, 60, 62) associated with each billing zone, two virtual routers being interconnected by a virtual circuit (38, 40, 42) transmitting all the traffic exchanged between the two associated billing zones so that the traffic flowing between the two billing zones can be measured and therefore precisely billed to the customer.
摘要:
An adaptive apparatus and method for managing a playout buffer (POB) in an edge node of a packet-based data communications network, such as an ATM network, in order to reduce the end-to-end communication delay introduced thereby and to allow the POB filling level to be corrected in the event of clock speed differences. A monitoring mechanism determines if the minimum filling level of the playout buffer over a time period whereby the average filling level of the playout buffer is reduced according to the minimum filling level of the playout buffer over the time period.
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.