JP5183460B2 - Packet scheduling method and apparatus - Google Patents

Description

  The present invention relates to a packet scheduling method and apparatus, and more particularly, to a technique using DS-SWFQ (Delay Sensitive-Simulated Weighted Fair Queuing).

  Generally, when traffic from a plurality of users on a plurality of lines is multiplexed on a single line, if there is an input exceeding the line speed to be output, congestion occurs and packet discard due to buffer overflow occurs. As a result, there is a possibility that the band of a certain user affects the band of another user.

Therefore, conventionally, in order to avoid the above-described problem, a packet scheduling method has been developed in which a minimum guaranteed bandwidth is set for each user and fair bandwidth control is performed so that the set guaranteed bandwidth or more can be used without fail.
Also, on the network, in order to comfortably use applications that require real-time performance such as audio and video, for example, complete priority control (allows low-delay transfer) and bandwidth control (enables bandwidth guarantee) ) To perform QoS control such as guarantee of communication bandwidth and guarantee of delay time by performing appropriate packet scheduling.

Under such circumstances, a packet scheduling method for QoS control has been proposed (for example, see Patent Document 1).
In Patent Document 1, a packet scheduling method based on the WFQ method that calculates a scheduled output completion time according to a weight proportional to the arrival packet length and the guaranteed bandwidth of the user, and sequentially outputs the packets with the smallest scheduled output completion time. Is disclosed.

  Patent Document 1 discloses that a packet (high priority class) for which a low delay transfer of a certain user is required is output by full priority control and a packet (low priority class) for which a low delay transfer is not required is output. In addition, a scheduling method for guaranteeing the total bandwidth of the high priority class and the low priority class by reflecting the bandwidth of the user is disclosed.

  Furthermore, in the above scheduling method, when a new head packet is generated, that is, when a packet arrives in an empty queue (new head registration), or when a packet is read from a queue having two or more packets (Next new top registration by reading) shows a method of calculating the scheduled output completion time and executing the sorting process.

According to the scheduling method, for example, if the input line speed is for two 10 Gigabit Ethernet (registered trademark) lines and the output line speed is for one 10 Gigabit Ethernet (registered trademark) line, the low priority class is selected. In the case of outputting, as shown in FIG. 3, within the shortest packet time (64-byte packet time: 67.2 ns), the new head registration is performed twice, the read processing is performed once, and the next update by reading is performed. It is necessary to register the head once.
When a high priority class is output, as shown in FIG. 4, the maximum priority class linkage process is performed once and new head registration is performed twice as shown in FIG.

3 and 4 are explanatory diagrams showing an example of the breakdown of the processing time by the conventional packet scheduling method, and FIG. 3 shows the processing time within the shortest packet time of the output line speed when the low priority class is output. The breakdown is shown.
FIG. 3 shows a breakdown of processing time when realized by the FPGA of the current latest process (65 nm). At the maximum, new head registration occurs twice, reading processing occurs once, and reading is performed. Registration process occurs once, and 20G input and 10G output are limited.

  On the other hand, FIG. 4 shows the breakdown of the processing time within the shortest packet time of the output line speed when the high priority class is output, but the registration processing of the low priority class is slightly increased. Although it is possible, it turns out that there is a limit.

JP 2007-13462 A

  In the conventional packet scheduling method, it is necessary to register new head information of newly arrived packets, read processing, and register next head packet information by reading within the shortest packet time at the output line speed. If the increase in the number, the registration process of the new head information of the new arrival packet increases, so the time for performing the registration process of the new head information is insufficient and the input line speed cannot be improved beyond a certain level. There was a problem.

  The present invention has been made to solve the above-described problems, and in particular, to obtain a scheduling method and apparatus capable of performing low delay transfer and bandwidth control even when the input line speed increases. Objective.

The packet scheduling method according to the present invention is a packet scheduling method for determining the output order of packets stored in each of a high priority class queue and a low priority class queue distinguished for each user. A packet distribution step for identifying the priority class and user of the packet and distributing the packet to the high priority class queue or the low priority class queue; and (b) notifying the user identification information and the packet length of the packet output from the high priority class queue. A high priority class output packet information notification step; and (c) when the packet is written to the low priority class user queue when the corresponding queue is empty, and the user identification information and the packet length are notified. New head information notifying step; (d) low priority class When there are two or more packets in the corresponding queue when a packet with a read command is output in the DS-SWFQ control step of (e) from the user queue of (e), the user identification information of the next leading packet and Output at a predetermined timing based on each information in the next head information notifying step by reading for notifying the packet length, and each of the steps (e), (b) to (d) and the weight information table holding step (f) A DS-SWFQ control step for scheduling a minimum bandwidth guarantee to select a queue to be selected and give a read command to the next head information notifying step by reading of (d); and (f) a DS-SWFQ control step of (e). A weight information table holding step for providing weight information for each user as set bandwidth information; and (g) a high priority class. (E) DS-SWFQ control which controls the output of the low priority class when there is no packet in the high priority class. A priority output control step for issuing an instruction to output when there is a packet to be output in the step ;
In step (c), the new head information notifying step at the time of input includes the user identification information and the packet length notified from the low priority class user queue when the new head packet is generated. It includes a FIFO step that holds the information and packet length in the order of input. Information is sequentially read out by the FIFO step, and packet information is transmitted to the DS-SWFQ control step (e) according to the processing status .

  According to the present invention, even when the input line speed increases, low delay transfer and bandwidth control can be performed.

Embodiment 1 FIG.
1 and 2 are block diagrams showing a packet scheduling method and apparatus according to Embodiment 1 of the present invention. Typically, the functional configuration and queue configuration of the packet scheduling apparatus are schematically shown in a flow diagram (in order of processing execution). ing.

FIG. 1 shows the overall configuration of the packet scheduling apparatus, and FIG. 2 shows in detail the functional configuration of the main part (first information holding unit 6 at the time of input) in FIG.
The configurations shown in FIGS. 1 and 2 are merely examples, and the present invention is not limited thereto. For example, the high priority class and the low priority class that are output with priority may be configured as a plurality of classes.

  In FIG. 1, the packet scheduling apparatus includes an input 1, a distribution unit 2, a high priority class queue 3, a low priority class queue user (1) 4 (1) to a low priority class queue user (n) 4 (n). A high-priority class output packet information holding unit 5, a new head information holding unit 6 at the time of input, a next head information holding unit 7 by reading, a DS-SWFQ control unit 8, a weight information table 9, and a priority output A control unit 10 and an output 11 are provided.

  Input 1 indicates a line speed equal to or higher than the total bandwidth of a plurality of lines, and indicates one or more data signal lines multiplexed so as not to be discarded. A plurality of priority classes to be subjected to packet scheduling are indicated. It shows a data stream such as Ethernet (registered trademark) packets of a plurality of users.

  The distribution unit 2 identifies the priority class and the users (# 1 to #n) by looking at the contents of the packet header and the like in the data stream of the input 1, and according to the identification information, each queue (high priority class queue) 3 or low priority class queue users (1) 4 (1) to low priority class queue users (n) 4 (n)).

The high priority class queue 3 has a function of storing the high priority class packets distributed by the distribution unit 2 in the order of input.
The high-priority class queue 3 has a function of discarding when a packet size cannot be stored in the queue at the time of storage, and a high-priority class output at the time of packet reading by the read command H from the priority output control unit 10 It has a function of notifying packet information holding unit 5 of packet information (user number and packet length).

  The low-priority class queue users 4 (1) to 4 (n) store the low-delay class packets in the corresponding queues according to the low-priority class information and user information distributed by the distribution unit 2. In each queue, one is stored especially from an empty state, so that when a new head is generated, it has a function of notifying the user number and the packet length to the new head information holding unit 6 at the time of input.

  The low-priority class queue users 4 (1) to 4 (n) have a function of discarding a packet when the packet cannot be stored in the queue when the packet is stored, and the DS-SWFQ control unit 8 When the read commands (1) to n are given, the head packet is output, and when two or more packets are stored in the corresponding queue, the information on the head packet (user number) is newly added. And packet length) to the next head information holding unit 7 by reading.

  In FIG. 1, the high-priority class queue 3 and the low-priority class queue users 4 (1) to 4 (n) are shown as individual functional blocks. However, the high-priority class queue 3 and the low-priority class queue user 4 (1 ) To 4 (n) may use physically one memory or physically separated memory as long as the order of each queue can be maintained.

  When a packet is output from the high priority class queue 3, the high priority class output packet information holding unit 5 temporarily holds the user number and packet length, and the DS-SWFQ control unit 8 stores the user number and packet length. It has a function to notify.

  When the new head information holding unit 6 at the time of input stores a packet in any queue of the low priority class queue users 4 (1) to 4 (n), It has a function of receiving the notification of the length and user number, temporarily holding it, and notifying the DS-SWFQ control unit 8 as new registration information.

The new head information holding unit 6 at the time of input constitutes the main part of the present invention, and holds new head information corresponding to the maximum number of low priority class queues (that is, the number of users) as shown in FIG. It includes a FIFO (First In First Out) 12 of a possible size and has a function of notifying the DS-SWFQ control unit 8 of new head information according to the processing status of the DS-SWFQ control unit 8.

  The next head information holding unit 7 by reading has a packet output from any of the low priority class queue users 4 (1) to 4 (n), and when two or more packets are stored in the corresponding queue, It has a function of receiving packet information (user number and packet length) from any of the low-priority class queue users 4 (1) to 4 (n), temporarily holding it, and transmitting it to the DS-SWFQ control unit 8.

  The DS-SWFQ control unit 8 includes packet information (user number and packet length) from the high priority class output packet information holding unit 5, the new head information holding unit 6 at the time of input, and the next head information holding unit 7 by reading. And the bandwidth information for each user stored in the weight information table 9, the most suitable queue is selected from the low priority class queue users 4 (1) to 4 (n), and a read command is output. Has the function of Note that the calculation and procedure described in the publicly known document (the above-mentioned Patent Document 1) can be applied to the process of selecting the optimum queue at this time.

  The weight information table 9 holds weight values that are set bandwidth information of the users # 1 to #n, and has a function of notifying the weight value of the corresponding user in response to a request from the DS-SWFQ control unit 8. Have. Note that setting and changing values are processed by rewriting a table from a known external interface (not shown).

The priority output control unit 10 outputs the output 11 to the high priority class queue 3 and the DS-SWFQ control unit 8 that performs output control of packets from the low priority class queue users 4 (1) to 4 (n). It has a function of outputting a read command according to the output line speed.
Specifically, when a packet exists in the high priority class queue 3, the priority output control unit 10 outputs a read command H to the high priority class queue 3, and no packet exists in the high priority class queue 3. When the low priority class queue users 4 (1) to 4 (n) have a packet, the DS-SWFQ control unit 8 has a function of outputting a read command L.

Next, the operation according to the first embodiment of the present invention shown in FIGS. 1 and 2 will be described.
First, processing at the time of packet storage will be described.
When a packet arrives at the input 1, the distribution unit 2 identifies the priority class (high priority class or low priority class) and the user number (# 1 to #n) by looking at the contents of the packet header, etc. Based on this, processing for storing packets in the high priority class queue 3 or the low priority class queue users 4 (1) to 4 (n) is performed.

  When the packet is stored in any of the low priority class queue users 4 (1) to 4 (n) in the above processing by the distribution unit 2, one is stored from the queue information of the corresponding low priority class queue from the empty state. Only when this is done, the stored packet information (user number and packet length) is notified to the new head registration information holding unit 6 at the time of input. On the other hand, in the above process, nothing is executed when stored in the high priority class queue.

Subsequently, the new head registration information holding unit 6 at the time of input can store the packet information notified from the low priority class queue users 4 (1) to 4 (n) for the number of low priority class queues. Input to the FIFO 12, wait for an output request from the DS-SWFQ control unit 8, and output packet information to the DS-SWFQ control unit 8 in response to the output request.

  The DS-SWFQ control unit 8 performs processing according to the following priority orders 1 to 4, a high priority class information holding unit 5, a new head information holding unit 6 at the time of input, and a next head information holding unit 7 by reading. In response to this, a read request is issued, and a sort process based on a virtual time FIFO and a linked registration process are performed. Note that the read process by the read instruction L from the priority output control unit 10 is the process having the highest priority. However, when other processes are being executed, the read instruction L is promptly performed after the process being executed is completed. It is assumed that the reading process is performed.

The processes according to the following priorities 1 to 4 are known from the above-mentioned Patent Document 1.
Priority 1: Read processing by read command L Priority 2: Next top registration processing at the time of reading Priority 3: High priority class linkage registration processing Priority 4: New top registration processing

  In addition, at the time of the registration process of the priority orders 2 to 4, the sort process and the cooperation registration process by the virtual time FIFO are performed using the set bandwidth information of each user stored in the weight information table 9.

Next, processing at the time of reading to the output 11 will be described.
The priority output control unit 10 grasps the existence status of each of the high priority class queue 3 and the low priority class queue users 4 (1) to 4 (n), and a packet exists in the high priority class queue 3. In this case, a read instruction H to the high priority class queue 3 is issued, the packet does not exist in the high priority class queue 3, and the packet is sent to any of the low priority class queue users 4 (1) to 4 (n). If it exists, a read command L is issued to the DS-SWFQ control unit 8.
At this time, the packet output interval to the output 11 is sequentially controlled at a predetermined timing, and a read instruction for the next packet is issued.

  When a packet is output from the high priority class queue 3 that has received the read command H, the high priority class queue 3 uses the packet information (user number and packet length) of the packet to be output to the high priority class output packet information holding unit 5. The high priority class output packet information holding unit 5 holds the packet information. Hereinafter, the high priority class output packet information holding unit 5 waits for an output request from the DS-SWFQ control unit 8 and outputs packet information to the DS-SWFQ control unit 8 in response to the output request.

  Upon receiving the read instruction L, the DS-SWFQ control unit 8 obtains the low priority class queue number from the time virtual time FIFO closest to the current virtual time, and obtains the corresponding low priority class queue (low priority class queue user 4 (1)). -4 (n)), a read instruction (any one of read instruction (1) to read instruction (n)) is issued.

  The corresponding low-priority class queue that has received the read command holds the next head information by reading the next top packet information (user number and packet length) only if there are two or more packets in the queue. Notification to the unit 7.

  The next head information holding unit 7 by reading temporarily holds packet information received from any of the low priority class queue users 4 (1) to 4 (n) and waits for an output request from the DS-SWFQ control unit 8. The packet information is output to the DS-SWFQ control unit 8 in response to the output request.

  By performing the above processing, for applications that require real-time performance, output is performed with low delay, and the input line speed is further improved while guaranteeing the bandwidth (minimum guaranteed bandwidth) for all users for all classes. be able to.

  If the first embodiment of the present invention is not applied, the processing that must be performed within the shortest packet time of the output line speed is at least one reading process and one next head information registration process by reading. The new top registration process at the time of input was limited to twice (20 Gbps input and 10 Gbps output).

On the other hand, as in the first embodiment of the present invention, the new head information holding unit 6 at the time of input temporarily stores information corresponding to the maximum number of low priority class queues in the FIFO 12 to delay the timing at which a new head occurs. As a result, the input line speed can be further improved although a slight delay occurs in the low priority class.

In this case, since a class requiring low priority uses the high priority class queue, a slight delay can be allowed for the low priority class.
For example, when multiple packets of burst traffic are input to the low-priority class queue, the new head registration process at the time of input of the first packet is slightly delayed, but when the first packet is registered, it subsequently arrives at the same queue. Since the subsequent head information registration process by reading is always performed within the shortest packet time, the subsequent packets are output with a guaranteed minimum bandwidth.

  If burst traffic occurs in the high priority class, the output of the high priority class will not exceed the output line speed, so even if the input line speed is improved, the processing amount will not increase, causing a problem. Absent.

As described above, the packet scheduling method according to Embodiment 1 of the present invention determines the output order of the packets stored in the high priority class queue and the low priority class queue distinguished for each user. (A) a packet distribution step for identifying a priority class and a user of an input packet and distributing the packet to a high priority class queue or a low priority class queue; and (b) a packet output from the high priority class queue. A high-priority class output packet information notification step for notifying the user identification information and the packet length; and (c) user identification information when the queue is input in an empty state when a packet is written to the low-priority class user queue. And a new top information notifying step at the time of input for notifying the packet length, and (d) a low priority class When there are two or more packets in the corresponding queue when a packet with a read command is output in the DS-SWFQ control step of (e) from the user queue, the user identification information and packet of the next leading packet Based on the information in the next head information notifying step by reading to notify the length, the steps (e), (b) to (d), and the weight information table holding step (f), the information is output at a predetermined timing. A DS-SWFQ control step for scheduling a minimum bandwidth guarantee to select a power queue and give a read command to the next head information notifying step by reading (d), and (f) a DS-SWFQ control step of (e) A weight information table holding step for providing weight information for each user as set bandwidth information, and (g) a high priority class (E) DS-SWFQ control step that issues a command to output a packet from the high priority class if there is a packet, and controls the output of the low priority class if there is no packet in the high priority class And a priority output control step for issuing a command to be output when there is a packet to be output.

Moreover, the new leading information notification step during input, if the user identification information and packet length from the user queue when new head packet generation of low priority class has been notified, the user of the number of low priority class queues (c) A FIFO step for holding the identification information and the packet length in the order of input is included. The information is sequentially read out by the FIFO step, and the packet information is transmitted to the DS-SWFQ control step of (e) according to the processing status.

Further, the new head information notifying step at the time of input in (c) prepares a packet memory for each input line, and when a new head is generated at the same time when the arrival of a packet occurs in the FIFO step, a user of a low priority class is always provided. The output order of the new head information for the DS-SWFQ control step of (e) is determined by giving priority to the young number of the queue or by rotating the order by round robin.

Further, the packet scheduling apparatus (see FIGS. 1 and 2) according to Embodiment 1 of the present invention includes a high priority class queue 3 and low priority class queues 4 (1) to 4 (n) distinguished for each user. (A) a packet distribution unit that identifies the priority class and user of the input packet and distributes the packet to the high-priority class queue or the low-priority class queue. 2 and (b) a high-priority class output packet information holding unit 5 (high-priority-class output packet information notification unit) for notifying user identification information and a packet length of a packet output from the high-priority class queue 3; ) User identification information and packet when the corresponding queue is empty when writing to the low priority class user queue The new head information holding unit 6 at the time of input (new head information notification means at the time of input) and (d) the DS-SWFQ control unit 8 of (e) receives a read command from the low priority class user queue. When there are two or more packets in the corresponding queue at the time of outputting a packet, the next head information holding unit 7 by reading that notifies the user identification information and the packet length of the next head packet (next head information by reading) Notification means), and (e) based on the information in each means 5 to 7 and the weight information table 9, the queue to be output at a predetermined timing is selected and the read command is read to the next head information holding unit 7 by reading. DS-SWFQ control unit 8 that performs scheduling of the guaranteed minimum bandwidth, and (f) provides weight information for each user as set bandwidth information to the DS-SWFQ control unit 8 Eight information table 9 (g) If there is a packet in the high priority class, issue a command to output the packet from the high priority class, and if there is no packet in the high priority class, output the low priority class And a priority output control unit 10 that issues a command to be output when there is a packet to be output by the controlling DS-SWFQ control unit 8.

Further, the new head information holding unit 6 at the time of input, when the user identification information and the packet length are notified from the low priority class user queue when the new head packet is generated, the user identification information and the number of the low priority class queues. A FIFO 12 that holds packet lengths in the order of input is included, information is sequentially read out by the FIFO 12, and packet information is transmitted to the DS-SWFQ control unit 8 according to the processing status.

Further, the new head information holding unit 6 at the time of input prepares a packet memory for each input line, and when a new head is generated in the FIFO 12 at the same time when the packet arrives, the new head information holding unit 6 always keeps the young number of the low priority class user queue. Or the order of output of new head information to the DS-SWFQ control unit 8 is determined by rotating the order by round robin.

Thus, according to the first embodiment of the present invention, low delay transfer and bandwidth control can be performed even if the input line speed increases.
In addition, when the output line speed is low, processing can be performed at a speed that matches the output line speed, so processing can be performed at a lower clock rate, and power consumption can be reduced. There is also.

Further, the new head information holding unit 6 at the time of input prepares a packet memory for each input line, and when a new head is generated in the FIFO 12 at the same time when the packet arrives, the new head information holding unit 6 always keeps the young number of the low priority class user queue Is given priority, or the order of output of the new head information to the DS-SWFQ control unit 8 is determined by circulating the order by round robin. Therefore, when the input 1 has a plurality of lines, the packets arrive at the same time. Even in the case, the new head registration can be performed by making the generation order of the new head in a fair order using round robin or the like, and the fairness of the new head registration can be maintained.

It is a block diagram which shows the packet scheduling method and apparatus which concern on Embodiment 1 of this invention. FIG. 2 is a block diagram specifically illustrating a head information holding unit at the time of input in FIG. 1. It is explanatory drawing which shows the conventional packet scheduling method. It is explanatory drawing which shows the conventional packet scheduling method.

Explanation of symbols

  1 input, 2 distribution unit, 3 high priority class queue, 4 (1) to 4 (n) low priority class queue user, 5 high priority class output packet information holding unit, 6 new head information holding unit at input, 7 reading Next head information holding unit, 8 DS-SWFQ control unit, 9 wait information table, 10 priority output control unit, 11 output, 12 FIFO.

Claims (4)

In a packet scheduling method for determining an output order of packets stored in each of a priority class queue and a low priority class queue distinguished for each user,
(A) a packet distribution step of identifying a priority class and a user of the input packet and distributing the packet to the high priority class queue or the low priority class queue;
(B) a high priority class output packet information notifying step for notifying user identification information and a packet length of a packet output from the high priority class queue;
(C) a new head information notifying step at the time of notifying the user identification information and the packet length when the corresponding queue is empty when the packet is written to the low priority class user queue;
(D) When two or more packets exist in the corresponding queue when a packet with a read command is output from the low-priority class user queue in the DS-SWFQ control step (e) described later, Next head information notification step by reading to notify the user identification information and packet length of the packet,
(E) Based on the information in the steps (b) to (d) and the weight information table holding step (f) described later, a queue to be output at a predetermined timing is selected and the read command is a DS-SWFQ control step for performing scheduling of minimum bandwidth guarantee to be given to the next head information notification step by reading d);
(F) a weight information table holding step for providing weight information for each user as set bandwidth information with respect to the DS-SWFQ control step of (e) above;
(G) If there is a packet in the high priority class, issue a command to output the packet from the high priority class. If there is no packet in the high priority class, control the output of the low priority class. A priority output control step for issuing a command to be output when there is a packet to be output in the DS-SWFQ control step of (e) above,
Equipped with a,
The new head information notification step at the time of the input (c) is as follows:
A FIFO step of holding user identification information and packet length as many as the number of low priority class queues in the order of input when user identification information and packet length are notified from the low priority class user queue when a new head packet is generated,
A packet scheduling method characterized in that information is sequentially read out by the FIFO step and packet information is transmitted to the DS-SWFQ control step (e) according to the processing status . The new head information notification step at the time of the input (c) is as follows:
A packet memory is prepared for each input line, and when the arrival of a packet is simultaneous and a new head is generated in the FIFO step, the lower priority class user queue is always given priority, or in turn by round robin. 2. The packet scheduling method according to claim 1 , wherein the output order of the new head information for the DS-SWFQ control step of (e) is determined by cycling. In a packet scheduling device that determines the output order of packets stored in each of a high priority class queue and a low priority class queue distinguished for each user,
(A) a packet distribution unit that identifies a priority class and a user of an input packet, and distributes the packet to the high priority class queue or the low priority class queue;
(B) high priority class output packet information notification means for notifying user identification information and packet length of packets output from the high priority class queue;
(C) New head information notification means at the time of input for notifying the user identification information and the packet length when the queue is input in an empty state at the time of packet writing to the low priority class user queue;
(D) When two or more packets exist in the corresponding queue when a packet with a read command is output from the low-priority class user queue in the DS-SWFQ control means (e) described later, Next head information notification means by reading to notify the user identification information and packet length of the packet,
(E) Based on the information in the means (b) to (d) and the weight information table holding means (f) described later, the queue to be output at a predetermined timing is selected and the read command is a DS-SWFQ control means for performing scheduling for guaranteeing a minimum bandwidth to be provided to the next head information notification means by reading d);
(F) weight information table holding means for providing weight information for each user as set bandwidth information to the DS-SWFQ control means of (e) above;
(G) If there is a packet in the high priority class, issue a command to output the packet from the high priority class. If there is no packet in the high priority class, control the output of the low priority class. Priority output control means for issuing a command to be output when there is a packet to be output by the DS-SWFQ control means of (e) above,
Equipped with a,
The new head information notification means at the time of the input (c) is as follows:
A FIFO means for holding user identification information and packet length as many as the number of low priority class queues in the order of input when user identification information and packet length are notified from the low priority class user queue when a new head packet is generated;
A packet scheduling apparatus characterized in that information is sequentially read out by the FIFO means and packet information is transmitted to the DS-SWFQ control means (e) according to the processing status . The new head information notification means at the time of the input (c) is as follows:
A packet memory is prepared for each input line, and when the arrival of a packet is simultaneous and a new head is generated in the FIFO means, the lower priority class user queue is always given priority, or the order is round robin. 4. The packet scheduling apparatus according to claim 3, wherein the output order of the new head information for the DS-SWFQ control means of (e) is determined by circulating the data.

Images