JP3607135B2 - Bandwidth allocation method and bandwidth allocation circuit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a bandwidth allocation method and a bandwidth allocation circuit for allocating a communication bandwidth between a plurality of connections.
[0002]
[Prior art]
As a conventional bandwidth allocation method, for example, a method for realizing a service class called GFR (guaranteed frame rate) of ATM Forum has been proposed.
[0003]
However, in the case of an ideal GFR, compared with a user (referred to as a PCR user) who always sends out a cell at a PCR (peak cell rate) which is the maximum band allowed with the network, For users (referred to as MCR users) that send cells in a band corresponding to the MCR (minimum cell rate), which is a predetermined band set at the time, there is no preferential treatment for band allocation, and always MCR Thus, bandwidth allocation up to PCR is impossible.
[0004]
This will be described with reference to FIG. 1 showing the concept of cell reading by GFR. In FIG. 1, it is assumed that five users A to E having the same contract conditions communicate with each other using VC1 to VC5, of which four users A to D are PCR users and user E is an MCR user. To do. It is assumed that the group band GPCR is set to 2 × PCR = 10 × MCR. Since the GFR always shares the group band with the MCR ratio, the MCR user can always transmit only with the MCR. That is, even if user E inputs data at time 11 when the users A to D have completed communication for MCR and are communicating in a band exceeding the MCR, the GFR shows the GPCR as shown at time 15. Only 1/5 bandwidth is provided. Therefore, there is no benefit for the MCR user, which is a factor that promotes the PCR userization of the MCR user. As a result, when all users become PCR users, all users can always use the band only for MCR, and there is a problem that the significance of the GFR service does not exist.
[0005]
In particular, as described, for example, in the 1998 IEICE Society Conference Proceedings B-6-43 “Improvement of fairness of FIFO-type GFR circuit by virtual MCR” by Kei Tanaka et al. Since the allocation circuit is dependent on the input band and has a characteristic that a connection with a larger input band can obtain a larger output band, the problem of lack of fairness with respect to a connection with a smaller band becomes more apparent.
[0006]
[Problems to be solved by the invention]
In view of the above-described problems, an object of the present invention is to provide a band allocation method and a band allocation circuit in which the burst transmission band of an MCR user is improved as compared with GFR.
[0007]
[Means for Solving the Problems]
According to the bandwidth allocation method of the present invention , when a connection whose bandwidth allocation is equal to or greater than the guaranteed bandwidth is set as a suppression target connection, and a connection whose bandwidth is equal to or less than the guaranteed bandwidth is set as another connection, the suppression target connection and the other connection are observed through a certain period of time observation. And suppress the surplus bandwidth for the suppression target connection until the suppression time for setting the bandwidth allocation for the suppression target connection elapses or the bandwidth required for other connections decreases and an invalid bandwidth occurs. Only the guaranteed bandwidth is allocated, and the remaining bandwidth is allocated to other connections .
[0008]
In such a bandwidth allocation method of the present invention, the average bandwidth in the guaranteed bandwidth observation time may be set as the guaranteed bandwidth for the suppression target connection. Also, for connections whose average bandwidth allocation measured over a certain period of time is less than the guaranteed bandwidth, the average bandwidth is guaranteed bandwidth or guaranteed until the bandwidth allocated to the connection and the bandwidth allocation for other connections become fair. A bandwidth exceeding the bandwidth may be allocated. In this case, the upper limit value of the bandwidth to be allocated after exceeding the guaranteed bandwidth is set to a value that does not violate the parameter by the user parameter control for monitoring the transmission cell interval after the allocation, or for the cell that has exceeded the guaranteed bandwidth after the allocation. A value that does not cause CLP bit rewriting to a connection that exceeds the CLP bit that is a priority discard bit is set to a value that does not occur, or a value that does not cause discard after allocation.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, examples of the present invention will be described.
[0010]
[Example 1]
FIG. 2 is a diagram for explaining the configuration of an embodiment of the bandwidth allocation circuit of the present invention. In this embodiment, the allocation means 21 for allocating a bandwidth to each connection, the history observation means 22 for observing the allocation amount for each connection by the allocation means 21, and allocating a bandwidth higher than the guaranteed bandwidth by observation of the history observation means 22. History identifying means 23 for identifying a connection that has been assigned a bandwidth less than or equal to the guaranteed bandwidth, and information that should be preferentially assigned bandwidth to the connection that has been determined to be less than or equal to the guaranteed bandwidth by the history identifying means 23 When there is information in the connection that has been determined to be allocated under the guaranteed bandwidth by the history identification unit 23 using the presence information from the presence recognition unit 24 and the presence information from the presence recognition unit 24 as a trigger, the history identification unit 23 Allocation for connections subject to suppression determined to be allocated above the guaranteed bandwidth is a surplus bandwidth By suppressing the assignment only as guaranteed bandwidth, comprises a priority assignment means 25 assigns the connection to the rest of the band has been determined that the following allocation guaranteed bandwidth.
[0011]
Here, the observation by the history observation means 22 is an observation using an observation window (jumping window) that is switched at regular intervals, an observation using an observation window (sliding window) in which the time at which the assignment to the connection is performed is 0, etc. Can be used. When the allocation unit 21 follows weighted round robin allocation in which allocation is performed according to AND information with table information or register information indicating the allocation order or the number of allocations proportional to the presence of information for each connection and the weighting for each connection, priority allocation unit 25, by manipulating the existence of information for each connection for the connection to be suppressed, or table information or register information so that it is positive only at intervals corresponding to the guaranteed bandwidth of the connection, and false otherwise. Alternatively, priority is given by manipulating the value itself described in the table information or register information.
[0012]
FIG. 3 is a diagram showing the concept of cell reading according to the present invention. As in FIG. 1, five users A to E having the same contract conditions communicate with each other using VC1 to VC5, of which four users A to D are PCR users, and user E is an MCR user. Suppose there is. It is assumed that the group band GPCR is set to 2 × PCR = 10 × MCR. When user E inputs data at time 31 when users A to D are not communicating, as shown at time 35, MCR has priority over surplus bandwidth allocation, so depending on the combination, it may be transmitted by PCR. It becomes possible. This means that the transmission time for each burst transmission is shortened. For example, it is suitable for the transmission of traffic depending on the transmission time such as TCP / IP under the condition of a large round trip time (RTT). .
[0013]
Furthermore, although the jumping window is used for the observation here, the reset position of the observation window for observing the cell amount for each connection using the jumping window is preferably close to the same for all connections. This is for the protection of MCR users, that is, as shown in FIG. 3, when the observation window is reset at the same time, competition between PCR users is likely to occur. In the configuration of this embodiment, the connection to which the cell belongs may be replaced with a path, VP, VC, or the like.
[0014]
[Example 2]
In this embodiment, a guaranteed bandwidth observation time is set, and the bandwidth is guaranteed based on an average over that time. Accordingly, it becomes possible to quickly allocate the bandwidth to the connection that was allocated below the guaranteed bandwidth. At this time, the time or bandwidth that is excessively allocated to the connection whose average bandwidth allocation value during the fixed observation time is less than the guaranteed bandwidth is either allocated the guaranteed bandwidth as an average value for the connection, or is assigned to the connection. A bandwidth exceeding the guaranteed bandwidth is allocated until the allocated bandwidth and the bandwidth allocated to other connections become fair. Accordingly, in this embodiment, unlike the first embodiment, even when there is no surplus bandwidth, it is possible to allocate a sufficient bandwidth for connections below the guaranteed bandwidth. Over-allocation for connections whose allocated bandwidth is less than or equal to the guaranteed bandwidth by observation for a certain period of time is a value that is not determined to be a traffic parameter violation by a UPC or NPC installed in a passing device, or CLP bit rewriting by a device that rewrites CLP. A value that does not occur or a value that does not cause discard after allocation.
[0015]
Example 3
In this embodiment, the same bandwidth as the bandwidth assigned in the second embodiment is assigned to the priority connection that is equal to or lower than the guaranteed bandwidth, regardless of the amount of information to be assigned. For this reason, a usage rate monitoring unit for identifying a band actually used with respect to the allocated band is provided. The bandwidth allocation circuit of this embodiment is implemented in an OLT of a passive optical network (PON) described in, for example, ITU recommendation G983.1, and is allocated like a bandwidth allocation circuit that allocates a bandwidth to each ONT. Suitable for use away from the target device. In such an allocation target device, it is impossible to quickly transmit the presence / absence of information to be transmitted to the band allocation circuit due to the transmission delay based on the distance to the band allocation circuit. Bandwidth must be allocated according to the prospect. At this time, if it is counted as being used even though the bandwidth allocated in the prospect is not actually used, there is a disadvantage for the ONT with a small bandwidth used. However, in this embodiment, since only the effective utilization rate is counted as a use band, even in a situation where a delay is large, assignment without unfairness becomes possible.
[0016]
Example 4
In this embodiment, the connections allocated by the bandwidth allocation circuit are classified into a plurality of groups, the bandwidth to be allocated in preference to other connections in the same group is reduced, and the connections to be allocated in priority to other connections in the same group should be reduced. Suppresses the guaranteed bandwidth until the bandwidth runs out. For this reason, in the configuration of this embodiment, connections are grouped, a surplus band within the group is preferentially allocated to connections belonging to the group, and then a group that allocates surplus band to connections outside the group is set. Suitable for the case.
[0017]
Example 5
In this embodiment, as in the fourth embodiment, the connections are classified into a plurality of groups so as to maintain fairness within the same group. In other words, the time that is excessively allocated to a connection whose average bandwidth allocation is less than the guaranteed bandwidth for a certain period of time belongs to the same group as the guaranteed bandwidth or the bandwidth allocated to the connection as the average value of the connection. A bandwidth exceeding the guaranteed bandwidth is allocated until the bandwidth allocated to other connections becomes fair. Therefore, in the configuration of this embodiment, as in the fourth embodiment, the connections are grouped, the surplus bandwidth within the group is preferentially assigned to the connections belonging to the group, and then the surplus bandwidth is assigned to connections outside the group. Suitable when the group to be assigned is set.
[0018]
【The invention's effect】
As described above, according to the present invention, it is possible to provide a bandwidth allocation method and a bandwidth allocation device that allocate bandwidths preferentially to users transmitting with MCR.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a situation in which bandwidth allocation is performed for MCR users by GFR.
FIG. 2 is a diagram for explaining the configuration of an embodiment of a bandwidth allocation circuit of the present invention.
FIG. 3 is a diagram illustrating the concept of cell reading according to the present invention.
[Explanation of symbols]
21 Allocation unit 22 History observation unit 23 History identification unit 24 Presence recognition unit 25 Priority allocation unit

Claims (10)

In a bandwidth allocation method for allocating bandwidth to a plurality of connections each of which can set a guaranteed bandwidth,
When a connection whose bandwidth allocation is more than the guaranteed bandwidth is a connection to be suppressed, and a connection whose bandwidth is less than the guaranteed bandwidth is another connection,
The connection to be suppressed and other connections are identified by observation over a certain period of time until the suppression time for setting the bandwidth allocation for the connection to be suppressed elapses or the bandwidth required for other connections decreases and the invalid bandwidth becomes A bandwidth allocation method characterized by allocating only a guaranteed bandwidth in which a surplus bandwidth is suppressed for a suppression target connection until occurrence, and allocating the remaining bandwidth for other connections . The bandwidth allocation method according to claim 1, wherein an average bandwidth in a guaranteed bandwidth observation time is set as a guaranteed bandwidth for a suppression target connection. For connections where the average bandwidth allocation measured over a certain period of time is less than the guaranteed bandwidth, the guaranteed bandwidth or the guaranteed bandwidth until the bandwidth allocated to the connection and the bandwidth allocated to other connections become fair as an average value The bandwidth allocation method according to claim 1, wherein a bandwidth exceeding the bandwidth is allocated. 4. The bandwidth allocation method according to claim 3, wherein an upper limit value of a bandwidth to be allocated exceeding the guaranteed bandwidth is set to a value that does not violate a parameter by user parameter control for monitoring a transmission cell interval after the allocation. The upper limit value of the bandwidth that is allocated after exceeding the guaranteed bandwidth is a value that does not cause rewriting of the CLP bit for a connection that exceeds the CLP bit that is a priority discard bit for a cell that has exceeded the guaranteed bandwidth after allocation. The bandwidth allocation method according to claim 3. 4. The bandwidth allocation method according to claim 3, wherein an upper limit value of a bandwidth to be allocated exceeding the guaranteed bandwidth is a value that does not cause cell discard after the allocation. Classify connections into multiple groups and set the bandwidth allocation for the connections to be suppressed until the suppression time elapses or the bandwidth required by other connections in the same group decreases and there is no bandwidth to be allocated in the same group 7. The bandwidth allocation according to claim 1 , wherein only the guaranteed bandwidth in which the surplus bandwidth is suppressed is allocated to the suppression target connection, and the remaining bandwidth is allocated to the other connections. Method. When connections are classified into a plurality of groups and there are connections to be suppressed, the average bandwidth allocated by observation for a certain period of time is less than the guaranteed bandwidth. The bandwidth allocation according to any one of claims 1 to 7, wherein a bandwidth exceeding the guaranteed bandwidth is allocated until a bandwidth allocated to the other bandwidth and a bandwidth allocated to another connection belonging to the same group become fair. Method. Allocating means for allocating a bandwidth to each connection, history observing means for observing the allocated amount for each connection by the allocating means, a connection in which a bandwidth higher than the guaranteed bandwidth is allocated by observation of the history observing device, and a bandwidth below the guaranteed bandwidth A history identifying means for identifying a connection to which a bandwidth is allocated, a presence recognition means for recognizing that there is information to be preferentially bandwidth allocated to a connection determined to be allocated below the guaranteed bandwidth by the history identifying means, and Suppression determined by the history identification means to be allocated above the guaranteed bandwidth when there is information in the connection that has been determined to be allocated below the guaranteed bandwidth by the history identifying means, using the presence information from the presence recognition means as a trigger Allocation to the target connection suppresses the surplus bandwidth allocation to the guaranteed bandwidth only, and the remaining bandwidth Bandwidth allocation circuit characterized by comprising a priority assignment means for assigning the guaranteed bandwidth following assignment and determination that had been connections. 10. The bandwidth allocation circuit according to claim 9 , further comprising usage rate monitoring means for identifying a bandwidth actually used with respect to the allocated bandwidth.

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