摘要:
A method of detecting a failure in a network, which includes a transport plane comprised of a plurality of communication nodes performing optical cross-connect and a control plane comprised of a plurality of control nodes that are connected to and control the respective communication nodes, includes the steps of transmitting, from a control node connected to a communication node having detected a failure to an adjacent control node, a failure information message having a time indication indicative of a time at which the failure is detected, and identifying, at a given control node which received the failure information message, a location of the failure in response to the time indication.
摘要:
A transmission apparatus which can enhance the transmission quality and reliability by establishing a recovery-path efficiently at a high speed for failure circumvention. A recovery-path request message control block generates, sends, and receives a recovery-path request message containing failure location information and recovery-path setup information. A label assignment message control block generates, sends, and receives a label assignment message. A setup label information generation block generates setup label information. A recovery-path label table management block constructs and manages a recovery-path label table. A failure detection block detects the location of a failure. A failure notification message transfer block transfers a failure notification message containing failure location information. A recovery-path establishment block establishes a recovery-path by comparing failure location information contained in a failure notification message and failure location information contained in a recovery-path label table and by selecting setup label information corresponding to matching failure location information.
摘要:
A recovery-path request message control block generates, sends, and receives a recovery-path request message containing failure location information and recovery-path setup information. A label assignment message control block generates, sends, and receives a label assignment message. A setup label information generation block generates setup label information. A recovery-path label table management block constructs and manages a recovery-path label table. A failure detection block detects the location of a failure. A failure notification message transfer block transfers a failure notification message containing failure location information. A recovery-path establishment block establishes a recovery-path by comparing failure location information contained in a failure notification message and failure location information contained in a recovery-path label table and by selecting setup label information corresponding to matching failure location information.
摘要:
A method of detecting a failure in a network, which includes a transport plane comprised of a plurality of communication nodes performing optical cross-connect and a control plane comprised of a plurality of control nodes that are connected to and control the respective communication nodes, includes the steps of transmitting, from a control node connected to a communication node having detected a failure to an adjacent control node, a failure information message having a time indication indicative of a time at which the failure is detected, and identifying, at a given control node which received the failure information message, a location of the failure in response to the time indication.
摘要:
A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.
摘要:
Control messages for securing a communication quality are exchanged via a dedicated connection within an ATM network when a sending terminal in an IP network delivers data to a receiving terminal in another IP network via the ATM network. A resource reservation message sent from the receiving terminal is parsed by a boundary device located at the boundary between the IP and the ATM network, and a data transfer connection is established within the ATM network based on the information of the resource reservation message.
摘要:
In a first UPC, a PCR is set as a monitor rate for each connection. If a transfer rate of a cell exceeds the PCR set for the connection, the cell is discarded. In a second UPC, an ACR is set as a monitor rate for each connection. If the transfer rate of the cell exceeds the ACR set for the connection, a lower priority is assigned to that cell. Additionally, with a configuration where one UPC monitors a varying rate, a parameter change process is controlled by obtaining a time between a passage time of a detected B-RM cell and an arrival of a user cell and comparing the obtained time with maximum and minimum delay standard values. A parameter table including some parameters is provided. A header of an arrived cell in a forward direction is extracted, and it is determined whether or not the arrived cell is a violation cell using the leaky bucket algorithm, etc. If the arrived cell is a violation cell, it is discarded. An RM cell in a backward direction is received and extracted, and the parameter table is updated by calculating the minimum cell interval, etc. based on data included in a payload of the RM cell.
摘要:
A video quality monitoring method includes a distribution server measuring first video quality index values according to a full-reference method by comparing a video, distributed from the distribution server to a client through a network, with a degraded video, generated by causing multiple scenarios of quality degradation due to the network in the video in a pseudo manner, creating characteristic data of first quality degradation values, obtained by causing the quality degradation to vary with the scenarios at regular intervals, and the first video quality index values corresponding to the respective scenarios, and transmitting the characteristic data to the client; and the client measuring a second quality degradation value in the video distributed through the network, and calculating a second video quality index value, equivalent to a value according to the full-reference method, of the distributed video from the measured second quality degradation value and the characteristic data.
摘要:
A boundary apparatus on the transmission side provided on the boundary between an IP network accommodating a transmitting terminal and an ATM network separates the requests for bandwidth which are received from receiving terminals via boundary apparatuses on the reception side into a plurality of groups on the basis of a required bandwidth, establishes a point-multipoint connection between the boundary apparatus on the transmission side and each of the boundary apparatuses on the reception side for each group, and transmits the data from the transmitting terminal to each of the receiving terminals via the connection. When there is a change in the number of the requests for bandwidth due to the delivery of a new request for bandwidth or the interruption of a flow of requests, the boundary apparatus on the transmission side calculates the effective bandwidth allocation ratio of the group in which there is a change in the number of the requests for bandwidth, and if the effective bandwidth allocation ratio is not more than a preset value, the boundary apparatus separates the requests belonging to the group into two groups, and establishes a connection for each group.
摘要:
An ATM connection is a virtual communication path specified by VPI/VCI. A plurality of ATM connections that are directed to the same output line is defined as an ATM connection group. A connection UPC (Usage Parameter Control) facility is provided for each of the ATM connections and a connection group UPC facility is provided for the ATM connection group. The connection UPC facilities and the connection group UPC facility are operated in either the monitor mode or the control mode. In the monitor mode, when the rate of flow of packets into a network exceeds a threshold, a control unit is informed of it, but cells are allowed to enter the network as they are. In the control mode, when the rate of flow of cells into the network exceeds the threshold, cells the flow rate of which exceeds the threshold are discarded.