JP2013255159A - Communication device and priority control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve problems in a prior art technique about which in software processing, when the number of users increases, it requires a CPU used exclusively for WFQ which can be processed at high speed by DSP and the like in software processing, and in hardware processing, when user flows to be processed increase, tables to be stored increase, and it must be efficiently implemented in hardware.SOLUTION: In order to perform efficient WFQ processing, a band control queue management table has information on a weighted sequence number, and a write-in side or read-out side calculates the weighted sequence number of a frame, and stores it in a frame reception buffer. The read-out side determines read-out order in accordance with the weighted sequence number.

Description

  The present invention relates to a communication apparatus and a priority control method, and more particularly, to a communication apparatus and a priority control method in which a WFQ (Weighted Fair Queuing) function is implemented.

  In recent years, the increase in traffic from UNI (User Network Interface) to NNI (Network Node Interface) has been particularly remarkable due to diversification of applications used by end users, wider bandwidth, and an increase in data capacity to be exchanged. Therefore, in order to maintain the QoS (Quality of Service) of the communication network, there is a need to provide a bandwidth control function for controlling traffic in a communication device installed at the interface between UNI and NNI.

  In performing bandwidth control, there are data such as voice and images that do not allow delay (data to be prioritized) and communication such as mail and data communication that allow relatively delay. In order to respond to the user's request, the carrier needs to perform priority control with data priority.

  WFQ is one of the bandwidth control functions for realizing priority control. WFQ is a technique for changing the priority order of packets in accordance with the amount of data (volume, size, and importance). By giving priority to audio and image streaming, WFQ can secure a bandwidth for low priority services while realizing stable streaming. WFQ is one of queuing algorithms for determining which queue packet to send from when there are a plurality of queues. WFQ sets weights for the queues according to the bandwidth and priority assigned to each queue, and considers the packet size. According to WFQ, a packet with a large size has a relatively low priority during transmission.

There are various methods for mounting a WFQ on a device, which are roughly classified into hardware processing and software processing.
As a background art of this technical field, there is Patent Document 1. Patent Document 1 implements WFQ with software. Specifically, the frame length and class queue information is read from the received frame, and the reading order (sequence number) is calculated based on the information. At this time, a sequence number is assigned to the frame before writing to the reception frame buffer (queue buffer), and the sequence number is referred to when reading from the reception frame buffer (queue buffer), and the frame is read from the frame with a high priority.

JP 2001-197110 A

  In general, when the WFQ function is realized, it can be realized by both software processing and hardware processing. However, in Patent Document 1 in which software processing is performed, there is a possibility that the delay in reading data stored in the priority class queue increases in proportion to the increase in the number of users and the increase in the number of class queues. As a result, there is a possibility that a delay occurs in communication such as audio and video that does not allow a delay, resulting in a decrease in bandwidth.

  In order to identify the flow, the user flow is identified by VLAN. When the number of users increases in realizing WFQ for each user, a software-dedicated CPU for WFQ that can process at higher speed than DSP is required. become. Also, when hardware processing is performed, the number of tables to be stored increases when the number of user flows to be processed increases. If hardware processing is not performed efficiently, a delay may occur and this may cause a reduction in bandwidth. Specifically, it is necessary to consider an algorithm for efficiently calculating and processing a weighted sequence number that is a bandwidth control parameter, and reading from a frame having the smallest weighted sequence number with a smaller processing sequence even during frame reading.

  The above-described problems include a WR control unit that writes to one of a plurality of queues of the frame reception buffer based on queue storage information of the received frame, and an RD control unit that reads a frame from one of the plurality of queues of the frame reception buffer; A queue management table that records a weighted sequence number and a round number for each queue, and the WR control unit or the RD control unit is a weighted sequence that depends on the priority and length of the frame for each frame. The number is calculated and recorded in the queue management table, and the RD control unit selects a queue from which frames are read based on the priority of the queue and the weighted sequence number, and the weighted sequence number of the selected queue is the round number. This can be achieved by a communication device that records in the queue management table.

  In addition, a WR control unit that writes to one of a plurality of queues of the frame reception buffer based on queue storage information of the received frame, an RD control unit that reads a frame from one of the plurality of queues of the frame reception buffer, and each queue Priority control method in a communication apparatus comprising a weighted sequence number and a queue management table for recording a round number, wherein a priority and length of a frame are determined for each frame in a WR control unit or an RD control unit. A step of calculating a weighted sequence number that depends on the weight, a step of recording the weighted sequence number in the queue management table, and a RD control unit reading a frame based on the priority of the queue and the weighted sequence number The step of selecting the queue and the weighted The Nsu number as round number, and recording the queue management table, the priority control method comprising, can be achieved.

  It is possible to provide a communication apparatus that has a weighted sequence number information in a table and can sufficiently cope with a general-purpose FPGA by performing WFQ processing efficiently.

It is a block diagram explaining the structure of the network containing the communication apparatus which mounts WFQ. It is a block diagram of a communication apparatus. It is a figure explaining the structure of the flame | frame preserve | saved at a queue. It is a functional block diagram of a bandwidth control unit that implements WFQ hardware processing. 3 is a functional block diagram of a bandwidth control unit that implements hardware processing of the WFQ according to the first embodiment. It is FIG. (1) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (2) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (3) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (4) explaining the operation | movement which stores the received flame | frame in a queue and reads from a queue. It is a figure explaining the table and buffer corresponding to the case where there are n user flows. It is a flowchart explaining a wraparound process. It is a figure explaining the structure of the other flame | frame preserve | saved in a queue. It is a block diagram which shows the function structure of WFQ of Example 2. FIG. It is FIG. (1) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (2) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (3) explaining operation | movement which stores the received flame | frame in a queue and reads from a queue. It is FIG. (4) explaining the operation | movement which stores the received flame | frame in a queue and reads from a queue.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings using examples. The same reference numerals are assigned to substantially the same parts, and the description will not be repeated. Also, the examples do not limit the invention.

  A network configuration will be described with reference to FIG. In FIG. 1, the network 100 includes an end user 10, a communication device 11, and a carrier network 19. The carrier network 19 includes an access line network 12, another carrier access line network 13, an ATM access network 14, an ether access network 15, a VLAN service network 16, a dedicated line network 17, and an edge SW (switch) 18. It is composed of

The ATM access network 14 is connected to the communication device 11-1. The communication device 11-1 is connected to the end users 10-1 and 10-2. The access line network 12 is connected to a communication device 11-2. The communication device 11-2 is connected to the end user 10-3. The other carrier access line network 13 is connected to the communication device 11-4. The communication device 11-4 is connected to the end user 10-5. The Ethernet access network 15 is connected to the communication device 11-3. The communication device 11-3 is connected to the end user 10-4.
From the viewpoint of the communication device 11, the carrier network 19 side is referred to as the NNI side. From the viewpoint of the communication device 11, the end user 10 side is referred to as the UNI side.

  The carrier network 19 is generally composed of a backbone network such as a VLAN service network 16 and a dedicated line network 17. These backbone networks are connected by an edge SW 18 or the like. The backbone network can communicate between networks.

  There are various access line networks 12 as contact points between these networks and the end user 10. Specifically, the access line network 12 is an ATM access network 14, an Ethernet access network 15, and an access line network 13 of another carrier.

The end user 10 accesses the carrier network 19 via the communication device 11 and executes communication with the opposite end user who wants to communicate. The end user 10 is a PC, a user network, or the like. As data to be exchanged between end users 10, there are data such as voice and image that cannot be delayed (data to be prioritized) and data such as mail or data communication that allows a relatively long delay.
In order to answer the user's request, the carrier gives priority to the data and performs priority control. The communication apparatus 11 implements priority control by implementing WFQ, which is one of priority control functions.

  With reference to FIG. 2, the functional block of a communication apparatus is demonstrated. In FIG. 2, the communication device 11 includes a PHY 20, a frame separation unit 21, a control frame termination unit 22, a control frame generation unit 23, a multiplexing unit 24, and a band control unit 25.

  The PHY 20 performs physical layer termination processing of the received frame. The frame separation unit 21 separates the control frame from the NNI side and the downlink user frame. The control frame termination unit 22 terminates the separated control frame. The control frame generation unit 23 generates a control frame for controlling the bandwidth of the uplink signal. The multiplexing unit 24 multiplexes the generated control frame and the uplink user frame. The bandwidth control unit 25 implements WFQ.

  With reference to FIG. 3, the structure of the frame stored in the queue will be described. 3, in the case of the bandwidth control unit shown in FIGS. 4 and 5 described later, a weighted sequence number (SN) 50 calculated by a WR control block 30 described later is added to the head of the frame. The header portion includes COS (Class Of Service) or TOS (Type Of Service) / TC (Traffic Class) 51 and Length 52.

  COS or TOS / TC50 is storage queue information. COS or TOS / TC 50 is information for selecting a storage queue in the frame reception buffer 32 when a frame arrives. Length 52 is a parameter used when calculating a weighted sequence number.

  With reference to FIG. 4, the structure which implement | achieves WFQ by a hardware process is demonstrated about a band control part. In FIG. 4, the bandwidth control unit 25 includes a WR (write) control block 30, a bandwidth queue management table 31, a reception frame buffer 32, and an RD (read) control block 33.

  The WR control block 30 acquires queue storage information that identifies a user flow using frame reception as a trigger. The WR control block 30 stores the received frame in the frame reception buffer 32.

  The RD control block 33 acquires queue management information from the bandwidth control queue management table 31 triggered by detection of the presence of a frame in the reception buffer 32. The RD (read) control block 33 reads out a frame from the frame reception buffer 32 and transmits it.

  The bandwidth control queue management table 31 holds queue information of connections to be bandwidth controlled. The bandwidth control queue management table 31 includes a WA (Write Address) 312, frame head information 311, and an RA (Read Address) 314. The records of the bandwidth control queue management table 31 include class 3 (absolute priority), class 2, class 1, and class 0 in descending order of priority. Class 3 (absolute priority) is absolute priority and does not participate in WFQ. Therefore, the round number 313 is recorded in the frame head information 311 column of class 3 (absolute priority).

The round number 313 is a table for storing the weighted sequence number of the WFQ output frame. The round number 313 is provided for each flow.
The WR control block 30 includes a round number acquisition unit 301 and a weighted sequence number calculation and addition unit 302. The round number acquisition unit 301 acquires a round number 313 in class 3 (absolute priority) of the bandwidth control queue management table 31 in order to calculate a weighted sequence number. The weighted sequence number calculation and adding unit 302 calculates a weighted sequence number from the frame length of the arrived frame, the weight of the stored class queue, and the round number acquired in 301, and assigns it to the head of the frame.

  A specific description will be given along the flow of the frame. The WR control block 30 assigns a weighted sequence number to the head of the frame stored in the frame reception buffer 32. When reading a frame, the RD control block 33 performs reading in ascending order of the weighted sequence number.

  Processing of the WR control block 30 on the writing side will be described. A received frame arrives at the WR control block 30. The calculation method of the weighted sequence number differs depending on whether the queue in which the received frame is stored is an active class queue (Not Empty) or an inactive class queue (Empty) as follows. Note that the WR control block 30 determines whether the received frame is to be stored in the COS or the TOS / TC 51.

For an active class queue (Not Empty)
: Last weighted sequence number + Weight value of the corresponding class x number of frame bytes Inactive class queue (Empty)
: Acquired round number + weight value of corresponding class × number of frame bytes The WR control block 30 assigns the calculated weighted sequence number 20 to the head of the frame and stores it in the corresponding queue of the reception buffer 32. For the previous weighted sequence number in the case of the active class queue, the frame head information 311 that is the head address of the last frame stored in the class queue is read from the bandwidth control queue management table 31. The previous weighted sequence number is acquired from the address indicated by the read frame head information 311.

  Next, processing on the reading side will be described. The RD control block 33 reads the RA 314 of each class in the bandwidth control queue management table 31 when reading the frame. Next, the RD control block 33 reads a frame stored in each class queue indicated by the RA 314. The RD control block 33 compares the weighted sequence numbers assigned to the read frames, and sequentially reads out the frames with the smaller values. The RD control block 33 compares the weighted sequence numbers after reading the bandwidth control queue management table 31 and the frame reception buffer 32, and determines the class queue to be read.

  With reference to FIG. 5, another configuration for realizing WFQ by hardware processing will be described for the bandwidth control unit. In FIG. 5, the bandwidth controller 25 includes a WR control block 30, a bandwidth queue management table 31A, a reception frame buffer 32, and an RD control block 33. The frame reception buffer 32 is a first-in first-out (FIFO) memory.

  The WR control block 30 acquires queue storage information that identifies a user flow using frame reception as a trigger. The WR control block 30 stores the received frame in the frame reception buffer 32.

  The RD control block 33 acquires queue management information from the bandwidth control queue management table 31A triggered by the detection of the presence of a frame in the reception buffer 32. The RD (read) control block 33 reads out a frame from the frame reception buffer 32 and transmits it.

  A feature of the first embodiment is that the WR control block 30 assigns a weighted sequence number 411 to the frame. Note that the WR control block 30, the frame reception buffer 32, the RD control block 33, the round number 313, the round number acquisition unit 301, and the weighted sequence number calculation and addition unit 302 are the same as the operations described in FIG.

  The bandwidth queue management table 31A holds the queue information of the connection to be bandwidth controlled. The bandwidth control queue management table 31A includes a WA 312, a weighted sequence number 411, a prefetched weighted sequence number 412, and an RA 314. The records of the bandwidth control queue management table 31A include class 3 (absolute priority), class 2, class 1, and class 0 in descending order of priority. Class 3 (absolute priority) is absolute priority and does not participate in WFQ. Therefore, the round number 313 is recorded in the weighted sequence number 411 column of class 3 (absolute priority).

The weighted sequence number 411 of the bandwidth control queue management table 31 stores a sequence number for WFQ calculation.
The pre-read weighted sequence number 412 is read up to the top weighted sequence number of the next frame at the time of frame reading by the RD control block 33 and the value is stored as the pre-read weighted sequence number 412. The prefetch weighted sequence number 412 is used to select a packet to be read next.

  A specific description will be given along the flow of the frame. The WR control block 30 assigns a weighted sequence number 411 to the head of the frame stored in the frame reception buffer 32. When reading a frame, the RD control block 33 prefetches the weighted sequence number of the next frame.

  First, the WR control block 30 process on the writing side will be described. A received frame arrives at the WR control block 30. The calculation method of the weighted sequence number differs depending on whether the queue in which the received frame is stored is an active class queue (Not Empty) or an inactive class queue (Empty) as follows. The queue in which the received frame is to be stored is determined by COS or TOS / TC51.

For an active class queue (Not Empty)
: Last weighted sequence number + Weight value of the corresponding class x number of frame bytes Inactive class queue (Empty)
: Acquired round number 313 + weight value of corresponding class × number of frame bytes The WR control block 30 assigns the calculated weighted sequence number to the head (SN50) of the frame and stores it in the corresponding queue of the reception buffer 32.

  The WR control block 30 writes the weighted sequence number in the bandwidth control queue management table 31A. At this time, the WR control block 30 overwrites the weighted sequence number 411 of the corresponding class. The written weighted sequence number 411 is used for calculating the weighted sequence number of the next frame.

  If the queue for writing a frame to the frame reception buffer 32 is empty, the WR control block 30 overwrites the calculated weighted sequence number 411 in the prefetched weighted sequence number 412 area of the control queue management table 31A.

  The bandwidth control queue management table 31A also updates the weighted sequence number 411 assigned to the frame for the flow and class queue entries corresponding to the stored frame.

  Next, processing on the reading side will be described. The RD control block 33 compares and reads the prefetch weighted sequence number 412 when reading the frame. In the first reading, the same SN as the weighted sequence number 411 is written in the prefetched weighted sequence number 412 area in the WR control block 30, so that the values are compared and read. From the second time onward, the reading order is determined by the sequence number 412 with the prefetching weight prefetched in the first reading.

  Here, prefetching will be described. In the prefetching, the RD control block 33 reads up to the SN50 at the head of the next frame at the time of frame reading, and overwrites the sequence number area 412 with a prefetching weight in the bandwidth control queue management table 31.

  The bandwidth control queue management table 31A also updates the weighted sequence number 411 of the frame and the prefetched weighted sequence number 412 for the flow and class queue entry corresponding to the read frame together.

  The WR control block 30 assigns a weighted sequence number (SN) to the received frame. When the received frame is read from the queue, the RD control block 33 compares the weighted sequence numbers (SN) of the frames output from the queues, and transmits the frame having the smallest weighted sequence number (SN).

  The RD control block 33 records the weighted sequence number (SN) of the output frame in the bandwidth control queue management table 31A under the name of the round number. The round number is used when assigning SN. A rule for assigning weighted sequence numbers (SN) will be described below.

  The WR control block 30 acquires the frame length of the received frame in advance. When the queue to be stored is empty, the WR control block 30 sets (round number) + (frame length) × (frame weight of the corresponding queue) as a weighted sequence number (SN).

  When frames are accumulated in the queue to be stored, the weighted sequence number (SN) of the last accumulated frame is used, and the WR control block 30 calculates (SN of the last accumulated frame) + (frame length). ) × (frame weight of corresponding queue) is a weighted sequence number (SN).

  Next, a method for calculating the frame weight from the priority ratio will be described. The priority ratio and the frame weight have a reciprocal relationship. In the following description, the priority ratios (P2: P1: P0) of the class queues # 2, # 1, and # 0 are P2 = 9, P1 = 2, and P0 = 1.

In order to make the frame weight of each queue an integer, the following calculation is performed. The least common multiple of the priority ratio (P2: P1: P0) = (9: 2: 1) is calculated. In this case, the least common multiple is 18. Take the reciprocal of the priority ratio and multiply by the least common multiple. As a result of the calculation, the ratio of the frame weights of class queues # 2, # 1, and # 0 (W2: W1: W0) is
W2: W1: W0 = 2: 9: 18
It becomes.

  The WR control block 30 determines a queue to be stored by the COS or TOS / TC 51. The RD control block 33 compares the weighted sequence numbers (SN) of the frames output from the respective queues, and reads the frame having the smallest weighted sequence number (SN). However, when a frame is stored in the class queue # 3 (absolute priority), the frame in the class queue # 3 (absolute priority) is given priority.

  With reference to FIG. 6, storage and reading of received frames in a queue will be described. In FIG. 6A, a case where the following frames arrive in the order of (A), (B), and (C) will be described.

(A) Frame length: 100, class queue: # 0
(B) Frame length: 150, class queue: # 1
(C) Frame length: 200, class queue: # 1
The WR control block 30 calculates the weighted sequence numbers (SN) of the arrived frames (A), (B), and (C).
(A) Weighted sequence number (SN) calculation Since the class queue # 0 to be stored is empty, the WR control block 30 uses the round number. Note that the initial value of the round number is 0.

Weighted sequence number (SN)
= (Round number) + (frame length) x (frame weight: W0)
= 0 + 100 × 18
= 1800
(B) Weighted sequence number (SN) calculation Since the class queue # 1 to be stored is empty, the WR control block 30 uses the round number.
Weighted sequence number (SN)
= (Round number) + (frame length) x (frame weight: W1)
= 0 + 150 × 9
= 1350
(C) Weighted sequence number (SN) calculation Since the frame (B) is accumulated in the class queue # 1 to be stored, the WR control block 30 uses the SN of the frame accumulated last.
Weighted sequence number (SN)
= (SN of last accumulated frame) + (frame length) × (frame weight: W1)
= 1350 + 200 × 9
= 3150
The WR control block 30 assigns the calculated weighted sequence numbers (SN) to the heads of the frames (A), (B), and (C), and stores them in the corresponding queues 323 and 324, respectively.

  In FIG. 6B, the RD control block 33 compares the weighted sequence numbers (SN) of the frames (A) and (B) accumulated in the class queues # 0 and # 1 in FIG. Is output to a shaper (not shown) of the bandwidth controller 25. At this time, the class queue # 2 is not a comparison target because there is no frame in the queue.

  The RD control block 33 uses the weighted sequence number (SN) of the output frame (B) as a round number, and rewrites the round number area 313 from 0 to 1350.

Next, in FIG. 6C, a case where the following new frame (D) arrives will be described.
(D) Frame length: 250, class queue: # 2
(D) Calculation of Weighted Sequence Number (SN) Since the class queue # 2 to be stored is empty, the WR control block 30 uses the round number.
Weighted sequence number (SN)
= (Round number) + (frame length) x (frame weight: W2)
= 1350 + 250 × 2
= 1850
The WR control block 30 assigns the calculated weighted sequence number (SN) to the head of the frame (D) and stores it in the corresponding class queue # 2.

  With reference to FIG. 6D, the flow of reading from the queues of the frames (A), (C), and (D) currently accumulated in the queue will be described. In FIG. 6D, the RD control block 33 compares the weighted sequence numbers (SN) of the frames (A), (C), and (D) stored in the class queues # 0, # 1, and # 2. Since the smallest weighted sequence number (SN) is 1800 of the frame (A), the RD control block 33 first outputs the frame (A) to a shaper (not shown) of the bandwidth control unit 25. The RD control block 33 rewrites the round number area 313 from 1350 to 1800 using the weighted sequence number (SN) of the output frame (A) as the round number.

  Next, the RD control block 33 compares the sequence numbers of the frames (C) and (D) existing in the queue. Since the small weighted sequence number (SN) is 1850 of frame (D), RD control block 33 outputs frame (D) next. The RD control block 33 rewrites the round number area 313 from 1800 to 1850 using the weighted sequence number (SN) of the output frame (D) as a round number.

  Finally, the RD control block 33 outputs the frame (C) remaining in the class queue # 1. The RD control block 33 rewrites the round number area 313 from 1850 to 3150 using the weighted sequence number (SN) of the output frame (C) as the round number.

  With reference to FIG. 7, the bandwidth control queue management table and the frame reception buffer when the user flow is n flow will be described. In FIG. 7, when there are a plurality of user flows (n> 1), the bandwidth control unit 25 corresponds to the bandwidth control queue management tables 31A-1 to 31A-n and the frame reception buffers 32-1 to 32-n for the number of user flows. It comprises.

  The weighted sequence number and round number take finite values. For this reason, when the maximum value is exceeded (referred to as wraparound), the value returns to 0. When it returns to 0, it is not possible to simply compare weighted sequence numbers. This is because the sequence number returned to 0 is always the minimum value. The round-up flag is used to identify a queue in which wraparound has occurred and remove it from the comparison target. This will be described with reference to FIG.

  In FIG. 8, the WR control block 30 calculates a weighted sequence number (SN) (S80). The WR control block 30 determines whether the SN is equal to or greater than the wraparound threshold (S81). When YES, the WR control block 30 sets a wraparound flag for the priority queue (S82). When NO in step 81, the WR control block 30 performs SN comparison of the priority queues for which the wraparound flag is not set (S83), and proceeds to step 80.

  After step 82, the WR control block 30 determines whether the wraparound flag is set in all priority queues (S84). When YES, the WR control block 30 clears the wraparound flag of the all priority queue (S86). The WR control block 30 compares the SN (S87), and proceeds to step 80. When NO at step 84, the WR control block 30 transitions to step 83.

  With reference to FIG. 9, the frame configuration stored in the priority queue according to the second embodiment will be described. In FIG. 9, a frame 70A is composed of a header and a payload. The header includes COS or TOS / TC 51, which is information for selecting a queue to be stored, and frame information necessary for calculating a weighted sequence number. It contains a certain Length52. As is clear from the comparison with the frame 70 in FIG. 3, the SN is not included in the frame 70A.

  With reference to FIG. 10, a second embodiment in which the RD control block 33A generates a weighted sequence number 411 and determines the order of frames to be read from the frame reception buffer 32 according to the value will be described. In FIG. 10, the bandwidth control unit 25A includes a WR control block 30A, a bandwidth control queue management table 31B, a frame reception buffer 32, and an RD control block 33A.

  The bandwidth control queue management table 31B holds queue information of connections that are bandwidth control targets. The bandwidth control queue management table 31B includes a weighted sequence number 411 and an RA 314. The records of the bandwidth control queue management table 31B include class 3 (absolute priority), class 2, class 1, and class 0 in descending order of priority. Class 3 (absolute priority) is absolute priority and does not participate in WFQ. Therefore, the round number 313 is recorded in the weighted sequence number 411 column of class 3 (absolute priority).

The frame reception buffer 32 holds a class 3 queue (absolute priority) 321, a class 2 queue (weight: W2) 322, a class 1 queue (weight: W1) 323, and a class 0 queue (weight: W0) 324. To do. The frame reception buffer 32 is a FIFO memory.
The RD control block 33A includes a round number acquisition unit 331 and a weighted sequence number calculation unit 332. The round number acquisition unit 331 reads the round number 313 from the bandwidth control queue management table 31B. The weighted sequence number calculation unit 332 calculates a weighted sequence number based on the round number 311, the frame length 52, and the weight.

In the second embodiment, the RD control block 33A generates the weighted sequence number 411 and determines the order of reading according to the value. The specific operation will be described below.
The WR control block 30A stores the frames that have arrived at the WR control block 30A in the corresponding class queues 321 to 324 based on the COS or TOS / TC 51 of FIG.

  At the time of the first reading in the RD control block 33A (first reading), the RD control block 33A starts reading from a class queue having a high priority that is not Empty in the frame reception buffer 32. The weighted sequence number calculation unit 332 calculates a weighted sequence number from the number of bytes of the read frame. The weighted sequence number calculation unit 332 stores the calculated weighted sequence number 411 in the corresponding class of the bandwidth control queue management table 31B.

  Thereafter, at the time of the second reading, the RD control block 33A refers to the bandwidth control queue management table 31B at the time of reading, and reads the frames from the frame reception buffer 32 in the order of the queue with the smallest value of the weighted sequence number 411. The RD control block 33A calculates the weighted sequence number of the next frame by the weighted sequence number calculation unit 332 each time, and stores it in the corresponding class of the bandwidth control queue management table 31B.

  In the first embodiment, the weighted sequence numbers 411 of the respective class queues are known in advance, and the frames are read from the frame reception buffer 32 in ascending order of the weighted sequence numbers 411. However, in the second embodiment, the frame is read from the frame reception buffer 32 and the weighted sequence number 411 is calculated. As a result, the class queue to be read next is determined.

At this time, when the weighted sequence number 411 is updated by reading the frame in the RD control block 33A on the reading side, even the class in which the frame reception buffer 32 is empty is overwritten with the weighted sequence number 411 calculated for the read frame. . However, when the value of the weighted sequence number 411 to be overwritten is larger than the weighted sequence number 411 stored in the bandwidth control queue management table 31B in advance, overwriting is not performed.
On the other hand, the WR control block 30A on the writing side does not refer to or overwrite the weighted sequence number 411 at all.

  Here, the round number 313 will be described. The RD control block 33A sets the inactive queue = Empty, and sets the rounding number 313 as the weighting sequence number calculated for the packet of the queue having the smallest weighting sequence number 411 in each class of the bandwidth control queue management table 31B. To do. In addition, after the frame is read, the RD control block 33A overwrites the round number 313 in the weighted sequence number 411 of the class queue that is Empty in the flow.

Here, a method of calculating the weighted sequence number 411 will be described.
Weighted sequence number 411
= Weighted sequence number 411 read from the bandwidth control queue management table 31B + Weight value corresponding to class × number of frame bytes The above calculation is performed for both an active class queue (Not Empty) and an inactive class queue (Empty). It is a formula. At the time of the first reading (at the time of the first reading), the management table 31B does not hold the weighted sequence number 411 sequence number, so the round number (initial value 0) is used.

  With reference to FIG. 11, storage and reading of frames in the queue according to the second embodiment will be described. In FIG. 11, the weighted sequence number 411 of the bandwidth control queue management table 31B is described in the queue. This is for the convenience of illustration.

First, a case where the following frames arrive in the order of (A), (B), and (C) will be described with reference to FIG. 11A.
(A) Frame length: 100, class queue: # 0
(B) Frame length: 150, class queue: # 1
(C) Frame length: 200, class queue: # 1
The value of the first embodiment is used as the frame weight which is the priority ratio of each queue.
In the second embodiment, no processing is performed on the WFQ on the writing side, and the WR control block 30A stores in the queues 323 and 324 according to the COS or TOS / TC 51 of the frame 70A.

The weighted sequence number (SN) of the arrived frames (A), (B), and (C) is calculated on the reading side.
In FIG. 11B, the RD control block 33A refers to the bandwidth control queue management table 31B and selects a frame to be read. In the case of FIG. 11B, reading is started from a class queue with a high priority that is not Empty because it is the first reading (at the first reading). Therefore, the RD control block 33A first reads the frame (B) stored in the class queue # 1.

Next, the RD control block 33A performs weighted sequence number (SN) calculation of the read frame (B) as follows.
(B) Weighted sequence number (SN) calculation Since the frame (B) is the active class queue # 1, the RD control block 33A uses a round number.

Weighted sequence number (SN)
= (Round number) + (frame length) x (frame weight: W1)
= 0 + 150 × 9
= 1350
The RD control block 33A overwrites the round number 313 from 0 to 1350 with the weighted sequence number (SN) 1350 of the calculated frame (B). The RD control block 33A also overwrites the weighted sequence numbers (SN) of classes # 1 and # 2 in the bandwidth control queue management table 31B from 0 to 1350. The reason why the weighted sequence number (SN) of # 2 is overwritten from 0 to 1350 is because # 2 is Empty.

Next, a case where the following frame (D) arrives newly will be described with reference to FIG. 11C.
(D) Frame length: 250, class queue: # 2
In FIG. 11C, as in FIG. 11A, the WR control block 30A stores in the queue 322 in accordance with COS or TOS / TC51.

  With reference to FIG. 11D, the flow of reading from the queues of the frames (A), (C), and (D) currently accumulated in the queue will be described. 11D, the RD control block 33A compares the weighted sequence numbers of the classes # 2, # 1, and # 0 in which the frames of the bandwidth control queue management table 31B updated in FIG. 11C are accumulated.

  Since the smallest weighted sequence number (SN) is 0 in frame (A), RD control block 33A outputs frame (A) first.

Next, the weighted sequence number (SN) of the read frame (A) is calculated.
(A) Weighted sequence number (SN) calculation Since the frame (A) is the inactive class queue # 0, the RD control block 33A uses the weighted sequence number read in the bandwidth control queue management table 31B. .
Weighted sequence number (SN)
= (SN read in bandwidth control queue management table 31B) + (frame length) × (frame weight: W0)
= 0 + 100 × 18
= 1800
The RD control block 33A overwrites the weighted sequence number (SN) 1800 of the calculation result in the weighted sequence number area of the class queue # 0 of the bandwidth control queue management table 31B. In addition, the RD control block 33A overwrites the round number 313 from 1350 to 1800.

  Next, the RD control block 33A compares the weighted sequence numbers of the classes # 2 and # 1 in which the frames of the bandwidth control queue management table 31B are accumulated. Since the weighted sequence number is 1350 for both classes # 2 and # 1, the RD control block 33A next reads the frame (D) stored in class # 2 having a high priority.

The RD control block 33A calculates a weighted sequence number (SN) of the read frame (D).
(D) Weighted sequence number (SN) calculation Since the frame (D) is the inactive class queue # 2, the RD control block 33A uses the weighted sequence number read in the bandwidth control queue management table 31B. .
Weighted sequence number (SN)
= (SN read in bandwidth control queue management table 31B) + (frame length) × (frame weight: W2)
= 1350 + 250 × 2
= 1850
The RD control block 33A overwrites the weighted sequence number (SN) 1850 in the weighted sequence number area of the class queue # 2 in the bandwidth control queue management table 31B. Since the priority class queue # 0 also has an empty buffer, the RD control block 33A overwrites the weighted sequence number from 1800 to 1850. Further, the RD control block 33A overwrites the round number 313 from 1800 to 1850.

  Finally, the RD control block 33A reads the frame (C) stored in the class # 1 of the bandwidth control queue management table 31B.

The RD control block 33A calculates a weighted sequence number (SN) of the read frame (C).
(C) Weighted sequence number (SN) calculation Since the frame (C) is the inactive class queue # 1, the RD control block 33A uses the weighted sequence number read in the bandwidth control queue management table 31B. .
Weighted sequence number (SN)
= (SN read in bandwidth control queue management table 31B) + (frame length) × (frame weight: W1)
= 1350 + 200 × 9
= 3150
The RD control block 33A overwrites the weighted sequence number (SN) 3150 in the weighted sequence number area of the class queue # 1 in the bandwidth control queue management table 31B. The RD control block 33A also overwrites the weighted sequence number to 3150 because the priority class queues # 2 and # 0 also have empty buffers. Further, the RD control block 33A overwrites the round number 313 from 1850 to 3150.

Regarding the wraparound, the second embodiment may perform the same operation as the first embodiment.
According to the above-described embodiment, a communication apparatus capable of performing WFQ processing at high speed with a general-purpose FPGA can be provided.

  DESCRIPTION OF SYMBOLS 10 ... End user, 11 ... Communication apparatus, 12 ... Access line network, 13 ... Other carrier access line network, 14 ... ATM access network, 15 ... Ether access network, 16 ... VLAN service network, 17 ... Dedicated line network, 18 ... Edge SW, 19 ... Carrier network, 20 ... PHY, 21 ... Frame separation unit, 22 ... Control frame termination unit, 23 ... Control frame generation unit, 24 ... Multiplexing unit, 25 ... Band control unit, 30 ... WR control block, 31 ... Band control queue management table, 32 ... Frame reception buffer, 33 ... RD control block, 50 ... SN (sequence number), 51 ... Queue storage information, 52 ... Frame length information, 70 ... Frame, 100 ... Network, 301 ... Round Number acquisition unit, 302... Weighted sequence number calculation and giving unit, 3 DESCRIPTION OF SYMBOLS 1 ... Frame head information, 312 ... WA (Write Address), 313 ... Round number, 314 ... RA (Read Address), 321 ... Class 3 queue (absolute priority), 322 ... Class 2 queue (weight: W2), 323 ... Class 1 queue (weight: W1), 324 ... class 0 queue (weight: W0), 331 ... round number acquisition unit, 332 ... weighted sequence number calculation unit, 411 ... weighted sequence number, 412 ... prefetched weighted sequence number .

Claims (4)

A WR control unit that writes to one of a plurality of queues of the frame reception buffer based on queue storage information of the received frame;
An RD control unit that reads a frame from any of the plurality of queues of the frame reception buffer;
A queue management table that records a weighted sequence number for each queue and a round number;
With
The WR control unit or the RD control unit calculates, for each frame, the weighted sequence number depending on the priority and length of the frame, and records the weighted sequence number in the queue management table.
The RD control unit selects a queue from which a frame is read based on the priority of the queue and the weighted sequence number, and records the weighted sequence number of the selected queue as the round number in the queue management table. A communication device characterized by: The communication device according to claim 1,
The RD control unit calculates, for each frame, the weighted sequence number that depends on the priority and length of the frame, records the weighted sequence number in the queue management table, and the first reading is performed based on the priority of the queue. And a queue having the smallest weighted sequence number for the second and subsequent readings is selected. The communication device according to claim 1,
The WR control unit calculates the weighted sequence number depending on the priority and length of the frame for each frame, records the weighted sequence number in the queue management table, and adds the sequence number to the head of the frame. Write to any of a plurality of queues in the frame receive buffer;
When the frame is read, the RD control unit prefetches the sequence number of the next frame of the read frame and records it as a prefetch weighted sequence number in the queue management table. Based on the prefetch weighted sequence number A communication device characterized by selecting a queue to be read out. A WR control unit that writes to one of a plurality of queues of a frame reception buffer based on queue storage information of a received frame, an RD control unit that reads a frame from one of the plurality of queues of the frame reception buffer, and the queue A priority control method in a communication device comprising a weighted sequence number and a queue management table for recording a round number,
In the WR control unit or the RD control unit,
For each frame, calculating the weighted sequence number depending on the priority and length of the frame;
Recording the weighted sequence number in the queue management table;
In the RD control unit,
Selecting a queue to read frames based on the priority of the queue and the weighted sequence number;
Recording the weighted sequence number of the selected queue as the round number in the queue management table;
Priority control method.

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