Stream communication system and stream transfer control method

• US 6,445,679 B1
• Filed: 12/23/1998
• Issued: 09/03/2002
• Est. Priority Date: 05/29/1998
• Status: Expired due to Term

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Digital Vision Laboratories Corporation
• Inventors: Taniguchi, Koji, Tani, Hideaki
• Primary Examiner(s): Yao, Kwang Bin
• Application Number:
  US09/220,966
• Time in Patent Office: 1,350 Days
• Field of Search: 370/229, 370/230, 370/230.1, 370/231, 370/232, 370/233, 370/234, 370/235, 370/236, 370/252, 370/253, 370/400, 370/410, 370/428, 370/429, 370/395.2, 370/395.21, 370/395.4, 370/395.41, 370/395.42, 370/468
• US Class Current: 370/232
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/11 Identifying congestion
• CPC Class Codes: H04L 47/20 Traffic policing
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04L 47/29 using a combination of thresholds
• CPC Class Codes: H04L 65/1101 Session protocols
• CPC Class Codes: H04L 65/752 adapting media to network capabilities
• CPC Class Codes: H04L 65/80 Responding to QoS
• CPC Class Codes: H04L 9/40 Network security protocols
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

A stream communication system has a plurality of nodes and a network to which each node is connected, the node comprises a stream transfer device to which the encoding stream that data attribute information for every data blocks are added, and has a periodicity in the data structure is transferred, at least one node is allocated as a managing node, and the managing node manages at least one monitoring target node and a control target node, the stream transfer device of the control target node comprises stream conversion section for adjusting an amount of the transfer data as the effective transmission rate coincides to the specified transmission rate based on the data priority decided from data attribute information, the stream transfer device of the monitoring target node comprises internal information notification section for notifying the managing node the state of a load of the node, and the stream transfer device of the managing node comprises feedback control section for recalculating the transmission rate for real time transmission, and for notifying the control target node the result as a parameter setting message based on the load state notified from the monitoring target node and the set transmission rate.

Claims

1. A stream communication system comprising:

a plurality of nodes including a transmission node which is a leading stage of a stream transfer system and a reception node which is a final stage, and a network to which each node is connected,

each of said plurality of nodes has a stream transfer device with the function of receiving and transmitting an encoding stream which is divided into data blocks, data attribute information showing a data attribute in each data block is added, and a data structure has a periodicity,

at least one node is allocated as a managing node among said plurality of nodes,

said managing node manages at least one node as a control target node among said plurality of nodes, and manages at least one node located in the downstream of said control target node as a monitoring target node among said plurality of nodes,

said stream transfer device of said control target node comprises;

means for detecting an encoding cycle by analyzing said encoding stream;

means for obtaining a data priority from said data attribute information on each data block of said encoding stream;

means for measuring an amount of the transmission data every said encoding cycle;

means for controlling a transmission permission priority which is a first threshold used for transmission and judgment of the annulment of a data block based on results of the amount of the transmission data at a previous cycle;

means for controlling the number of transmission permission blocks which is a second threshold used for transmission and judgment of the annulment of a data block based on results of the amount of the transmission data at a previous cycle; and

stream conversion means for adjusting the amount of the transfer data by comparing the data priority of each said data by comparing the data priority of each said data block with the first threshold and the second threshold, when said encoding stream is transmitted to a next stage node, to coincide with the transmission rate for which the effective transmission rate is specified,

the stream transfer device of said monitoring target node comprises internal state notification means for measuring a load state in the node, and for notifying said managing node of a measurement result as an informative message of an internal state, and

the stream transfer device of said managing node comprises feedback control means for recalculating a transmission rate based on the load state notified from said monitoring target node and the transmission rate currently set, and for updating the transmission rate setting by notifying said control target node of the result as a parameter setting message.

2. A stream communication system according to claim 1, wherein

the internal state notification means of the monitoring target node comprises: data reception results notification means for notifying data reception results at the node; and

data processing results notification means for notifying data processing results at the node, and

wherein the feedback control means of the management node comprises;

link load judgment means for judging a link load between the monitoring target node and a front stage node based on a data reception result notified from the monitoring target node;

node load judgment means for judging a load of the monitoring target node based on a data processing result notified from the monitoring target node;

overall judgment means for giving judgment for determination of a control policy for the corresponding control target node while integrating respective load judgment results of the link load judgment means and the node load judgment means; and

parameter calculation means for calculating the parameter based on information which at least shows a judgment result of the overall judgment means and a transmission rate which is currently set at the control target node.

3. A stream communication system according to claim 2, comprising message transmission means for notifying said control target node of the parameter setting message which includes a parameter which said parameter calculation means calculated.

4. A stream communication system according to claim 2, wherein

at least one module, which can calculate a data processing result, among modules constructing the monitoring target node, is assigned with a role as a monitoring target module, and the monitoring target module is provided with the data processing results notification means,

wherein the feedback control means of the management node comprises module load judgment means for judging a load of the module based on a data processing result from the data processing results notification means provided to the monitoring target module of the monitoring target node, the number of module load judgment means being equal to the number of the monitoring target modules of the monitoring target node, and

wherein the node load judging means judges a node load by integrating a module load judgment result of the module load judgment means provided in a number equal to the number of the monitoring target modules.

5. A stream communication system according to claim 1,

wherein the encoding stream is cyclically inserted with transfer control reference information which serves as a standard in transfer control, and

wherein stream conversion means of the control target node updates the transmission permissible priority based on a transmission result in a previous cycle for each cycle which is distinguishable by the transfer control reference information.

6. A stream communication system according to claim 5, wherein the stream conversion means of the control target node transmits a data block with a higher priority than the transmission permissible priority, annuls a data block with a lower priority than the transmission permissible priority, increases, in the case of a data block with the same priority as the transmission permissible priority, the number of transmission data blocks by gradually increasing the number of transmission permissible data blocks showing the number of data blocks which can be transmitted in a cycle for each cycle which is judged by the transfer control reference information, wherein when all data blocks with the same priority as the transmission permissible priority can be transmitted in the cycle within a range of specified transmission rates, not only is the less transmission permissible priority given, but the number of transmission permissible data blocks is returned to an initial value and after a specified transmission rate is attained, update of the transmission permissible priority and the number of transmission permissible data blocks is ceased until a transmission rate setting change is requested by the parameter setting message.

7. A stream communication system according to claim 1, wherein the stream conversion means of the control target node, when a transmission rate change is requested by the parameter setting message, transmits a transition state starting notification message showing starting of a transition time period until an actual transmission rate reaches a requested, specified transmission rate to a management node as a transmitter of the parameter setting message and, when an actual transmission rate reaches the requested, specified transmission rate, transmits a transition state end notification message showing an end of the transition state time period to the management node, and

wherein the feedback control means of the management node temporarily ceases the feedback control of the stream conversion means of the control target node during a time period of a transition state from when the feedback control means receives the transition state starting notification message from the stream conversion means of the control target node until the feedback control means receives the transition state end notification message from the stream conversion means.

8. A stream communication system according to claim 7, wherein the stream conversion means of the control target node transmits, at regular intervals, an internal state notification message including a parameter giving a current transmission rate to the management node during a steady state time period from when the stream conversion means transmits the transition state end notification message until the stream conversion means transmits the transition state starting notification message, and

wherein feedback control means of the management node acquires a parameter giving a latest transmission rate set at the control target node while monitoring an internal state notification message including a parameter giving the transmission rate during a steady state time period from when the feedback control means receives the transition state end notification message from the stream conversion means of the control target node until the feedback control means receives the transition state starting notification message from the stream conversion means.

9. A stream communication system according to claim 4, wherein the link load judgment means comprises:

data reception results buffer adopting a first-in, first-out way for holding a plurality of

data reception results notified from the monitoring target node in the order of a time series;

weighing means for modifying the plurality of data reception results held in the data reception results buffer in the order of a time series with respective weights corresponding to the order; and

comparison operation means for outputting a link load result in three levels of Link Load;

Large/Link Load, Proper/Link Load, and Small based on a comparison result which is obtained by comparing an average of data reception result after the weighing by the weighing means with an upper bound threshold and a lower bound threshold corresponding to a range of permissible reception rates determined by a transmission rate set currently at the control target node.

10. A stream communication system according to claim 4, wherein

the module load judgment means comprises:

data processing results buffer adopting a first-in, first-out way for holding a plurality of data processing results notified from the monitoring target module in the monitoring target node in the order of a time series;

weighing means for modifying the plurality of data processing results held in the data processing results buffer in the order of a time series with respective weights corresponding to the order; and

comparison operation means for outputting a module load result in three levels of Module Load;

Large/Module Load, Proper/Module Load, and Small based on a comparison result which is obtained by comparing an average of data processing results after the weighing by the weighing means with an upper bound threshold and a lower bound threshold, determined in advance, of a permissible data processing result.

11. A stream communication system according to claim 4, wherein

the node load judgment means comprises:

latest module load holding means for holding a latest module load judgment result of module load judgment means whose number is equal to the number of the corresponding monitoring target modules; and

selection means for selecting a judgment result showing a largest module load as a node load judgment result from a latest module load judgment result of module load judgment means whose number is equal to the number of the monitoring target module(s) held in the holding means each time a new module load judgment result gets held in the latest module load holding means.

12. A stream communication system according to claim 2, wherein

the overall judgment means comprises:

latest judgment result holding means for holding a latest link load judgment result of the link load judgment means and a latest node load judgment result of the node load judgment means; and

matrix judgment means for acquiring a judgment result showing a control policy for the corresponding control target node by referring to a matrix table information in which there is described a relation of combinations of all link load judgment results and all node load judgment results conceivable in advance with a judgment result in which a control policy for the corresponding control target node is indicated in three levels composed of “

Transmission Rate;

Increased”

, “

Transmission Rate;

Unchanged” and

“

Transmission Rate;

Decreased”

by a combination(s) of the latest link judgment result and the latest node load judgment result which are held in the latest judgment results holding means.

13. A stream communication system according to claim 12, wherein

the overall judgment means further comprises:

a judgment result buffer adopting a first-in, first-out way for holding a judgment result of n times in the past acquired by the matrix judgment means in the order of a time series;

judgment result correction means for correcting a latest judgment result based on a continuous judgment result of m (m≦

n) times in the past which includes the latest judgment result in the judgment result buffer when the latest judgment result gets held in the judgment result buffer; and

window setting means for setting a window width indicating a value of m.

14. A stream communication system according to claim 13, wherein the judgment result correction means outputs the latest judgment result with no correction thereof if all the judgment results of m times in the past are “

Transmission Rate;

Increased”

or “

Transmission Rate;

Decreased,”

outputs the latest judgment result after changing “

Transmission Rate;

Unchanged”

to “

Transmission Rate;

Increased”

if all the judgment results of m times in the past are “

Transmission Rate;

Unchanged,” and

outputs the latest judgment result as “

Transmission Rate;

Unchanged,”

regardless of the latest judgment result if all the judgment results of m times in the past include different judgment results.

15. A stream communication system according to claim 14, wherein the window setting means sets the window width according to a latest judgment result held in the judgment result buffer.

16. A stream communication system according to claim 1, wherein the feedback control means comprises transmission rate control range setting means for setting a minimum transmission rate and a maximum transmission rate showing a control range for a transmission rate according to a specification from outside, and wherein the feedback control means changes a transmission rate to a parameter giving the maximum transmission rate when a transmission rate given by a calculated parameter exceeds the maximum transmission rate, and interrupts stream transfer or continues stream transfer while changing a transmission rate to a parameter giving the minimum transmission rate when the transmission rate is lower than the minimum transmission rate.

17. A stream communication system according to claim 16, wherein the transmission rate control range setting means sets a content rate to the maximum transmission rate when the specified maximum transmission rate exceeds the content rate of an encoding stream which is a target of feedback control.

18. A stream communication system according to claim 16, wherein the feedback control means comprises control mode setting means for setting a control mode which specifies whether stream transfer is to be interrupted or to be continued while changing a transmission rate to a parameter giving the minimum transmission rate when the transmission rate is lower than the minimum transmission rate according to a specification from outside.

19. A stream communication system according to claim 1, wherein all nodes except the transmission node which is leading stages of the stream transfer system function as said managing node, and each of said managing nodes monitors itself as a monitoring target node, and makes an upstream stage node a control target node.

20. A stream communication system according to claim 1, wherein one of the plurality of nodes is assigned with a role as the management node.

21. A stream transfer node which is applicable to any of a transmission node, a relay node and a reception node of a stream transfer system which transfers an encoding stream, which is divided into data blocks, each of the data blocks being associated with data attribute information showing a data attribute corresponding to each data block, and which has periodicity in its data structure, the stream transfer node being able to be assigned as a monitoring target node, a control target node and a management node, comprising:

stream conversion means for performing stream shaping processing in which a transfer data volume is adjusted so that a transmission rate reaches a specified transmission rate by transmitting or annulling each data block when the stream transfer node is assigned with a role as the control target node, and an encoding stream is transmitted to a node in a next stage, while decreasing stepwise a transmission permissible priority indicating a demarcation between data transmission/annulment by using a data priority determined based on the data attribute information attached to each data block and increasing stepwise the number of transmission permissible data blocks with the same priority as the transmission permissible priority in the same cycle;

internal state notification means for notifying a load state at the stream transfer node to a node which is assigned with a role as the management node for the same stream transfer node by an internal state notification message when the same stream transfer node is assigned with a role as the monitoring target node; and

feedback control means for performing feedback control to request a setting change of a transmission rate shown by a parameter while, when the stream transfer node is assigned with a role as the management node, the stream transfer node calculates the parameter showing a transmission rate at which real time transfer at a control target node is enabled based on information showing a load data notified by an internal state notification message from the internal state notification means of the monitoring target node and a transmission rate set currently at the control target node corresponding to the monitoring target node, and the stream transfer node notifies the parameter to the control target node by a parameter setting message according to the calculation result.

22. A stream transfer control method applied to a stream communication system which comprises a plurality of nodes including a transmission node which is a leading stage of a stream transfer system and a reception node which is a final stage, and a network to which each node is connected, wherein each of said plurality of nodes has a stream transfer device with the function of receiving and transmitting an encoding stream which is divided into data blocks, data attribute information showing a data attribute in each data block is added, a data structure has a periodicity, and at least one node is allocated as a managing node among said plurality of nodes, and said managing node manages at least one node as a control target node among said plurality of nodes and manages at least one node located in the downstream of said control target node as a monitoring target node among said plurality of nodes, comprising the steps of:

detecting an encoding cycle by analyzing said encoding stream;

obtaining a data priority from said data attribute information on each data block of said encoding stream;

measuring an amount of the transmission data every said encoding cycle;

controlling a transmission permission priority which is a first threshold used for transmission and judgment of the annulment of a data block based on results of the amount of the transmission data at a previous cycle;

controlling the number of transmission permission blocks which is a second threshold used for transmission and judgment of the annulment of a data block based on results of the amount of the transmission data at a previous cycle;

adjusting the amount of the transfer data by comparing the data priority of each said data block with the first threshold and the second threshold, when said encoding stream is transmitted to a next stage node, to coincide with the transmission rate for which the effective transmission rate is specified;

measuring a load state in the node, and notifying said managing node of a measurement result as an informative message of an internal state; and

recalculating a transmission rate based on the load state notified from said monitoring target node and the transmission rate currently set, and updating the transmission rate setting by notifying said control target node of the result as a parameter setting message.

23. A stream transfer control method according to claim 22, wherein when a transmission rate change is requested by the parameter setting message to the at least one control target node from the management node, there is transmitted a transition state starting notification message showing starting of a transition state time period until an actual transmission rate reaches a requested, specified transmission rate, by stream shaping processing, from a requesting node for the transmission rate change to a requested node and if the actual transmission rate reaches the requested specified transmission rate, there is transmitted a transition state end notification message showing an end of the transition state time period to the requesting node from the requested node to notify a transition state time period at the requested node to the requesting node and thereby the feedback control at the requesting node is temporarily ceased during the transition state time period.