JP2005354514A - Packet relay device in ring type transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To assure a band, in which a control packet is transferred, and to ensure the band for transferring a user data packet smoothly during communication with respect to a packet relay device of a ring type transmission device. <P>SOLUTION: When the transmission request of a control packet is generated, a transmission packet selecting unit 1-5 transmits the control packet preferentially. Meantime, the user data packet is buffered in a memory 1-13 to make the transmission stand ready temporarily. A traffic amount on the side of transmission path is monitored by a receive cell counter 1-9, and the inflow amount of user data packet from a terminal device is monitored by a packet inflow amount monitoring unit 1-16. If the values are over a threshold value, a packet is transmitted to which a band limiting flag is added. In another node which receives the packet added with the band limiting flag, the prescribed time is monitored by a timer 1-4, and meantime the transmission of the user data packet to the side of transmission path is stopped temporarily in another node. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a packet relay device in a ring type transmission device. As a result of the recent penetration of IP (Internet Protocol) related technology, asynchronous transmission such as Ethernet (registered trademark) from a conventional voice line or a transmission system using a synchronous line having a line speed such as 1.5 Mbit / s or 6 Mbit / s. Transmission systems using lines are becoming mainstream.

  The present invention guarantees that a bandwidth for smoothly transmitting a packet is always ensured in a transmission system using an asynchronous transfer line. In addition, it guarantees the bandwidth for sending and receiving control packets between the packet relay devices of the ring type transmission device.

  FIG. 8 shows a configuration example of a ring type transmission apparatus to which the present invention is applied. In the figure, nodes A to D are packet relay devices, and MAC1 to MAC5 are terminal devices such as personal computers that perform communication. The solid line arrows indicate the transfer paths for packets sent and received between terminal apparatuses, and the broken line arrows indicate the control packet transfer paths for exchanging transmission control information between the packet relay apparatuses (LAN accommodating boards) of each node. Yes.

In such a ring (loop) type transmission device, packets are smoothly transferred in a network (for example, network group a and network group b as shown in FIG. 8) that shares a bandwidth across a plurality of nodes. Each node classifies packets (cells) into the following three types and transfers them while performing management.
(1) User data packet that flows from the terminal device of its own node (2) Relay packet that flows from other nodes and relays to other nodes (3) Transmission / reception of MAC address management information between the nodes, and each packet relay device ( Control packet for exchanging transmission control information such as normality confirmation of LAN accommodating board)

  The packets (1) to (3) are all transferred using the same transmission band, and when there is an inflow amount exceeding the band, congestion occurs on the transmission path, thereby causing packet loss and communication. It will not be performed smoothly. The present invention performs priority processing so that the control packet (3) can be reliably transferred to each node, and secures a bandwidth so that the user data packet (1) can be smoothly transferred.

There are the following patent documents as prior art documents related to the present invention. Patent Document 1 relates to a relay device and a relay method for connecting a plurality of networks and communicating packets with each other, and relates to a relay device and a relay method for performing communication while maintaining communication quality (QoS). . Also, cited document 2 relates to a packet transfer device, a path management device, and the like that perform bandwidth management and control of bandwidth guarantee in an IP network.
JP 2003-158543 A JP 2002-344505 A

  A conventional ring-type transmission apparatus has a layer 2 switch function that distributes packets transmitted in a shared band across the nodes in each packet relay apparatus (LAN accommodating panel). Bandwidth cannot be guaranteed. Also, if the entire bandwidth is occupied by packet transfer from a specific node, the bandwidth cannot be used between other nodes. In particular, regarding information exchange using a control packet, there is a problem in that a control packet cannot be transferred if a user data packet uses the entire bandwidth.

  The present invention can guarantee a bandwidth for transferring control packets without being affected by the inflow of user data packets, and secure a bandwidth so that user data packets in communication can be smoothly transferred. An object of the present invention is to provide a packet relay device in a ring-type transmission device capable of performing the above.

  The packet relay apparatus in the ring-type transmission apparatus of the present invention is (1) sharing a transmission band among a plurality of nodes, and a user data packet flowing in from a terminal apparatus accommodated in the own node and flowing in from another node to another node. A packet relay apparatus of each node in a ring-type transmission apparatus that transfers a relay packet to be relayed and a control packet for exchanging transmission control information between nodes, and when there is a transmission request for the control packet, the control Control packet priority processing means for buffering the user data packet and temporarily waiting for transmission when there is a user data packet transmission request during the transmission of the packet preferentially, and a relay packet transmission request When there is no transmission request for the control packet, the relay packet is changed to the user data packet. Ri transmitted by priority, when the transmission request of the control packet is present, in which and a relay packet priority processing means for temporarily waits to send the relay packet is buffered.

  And (2) traffic volume monitoring means for monitoring the traffic volume on the transmission line side, and when detecting that the traffic volume exceeds a predetermined threshold, when there is a transmission request for the control packet, the user data packet is Control packet priority processing means for temporarily waiting for transmission by buffering and transmitting the control packet preferentially is provided.

  (3) When the sum of the traffic amount on the transmission path side and the inflow amount of the user data packet from the terminal device of the own node exceeds a predetermined threshold, a header for the user data packet from the terminal device of the own node Means for adding a bandwidth limit flag to the transmission and means for temporarily stopping transmission of the user data packet of the own node for a predetermined time when the user data packet with the bandwidth limit flag is received from another node It is equipped with.

  Further, (4) if the sum of the traffic amount on the transmission path side and the inflow amount of user data packets from the terminal device of the own node exceeds a predetermined threshold, a header for the user data packets from the terminal device of the own node When the above sum is equal to or less than a predetermined threshold, the band limit flag is canceled in the header and transmitted for the user data packet from the terminal device of the own node. And when the user data packet with the bandwidth limit flag is received from another node, the user data packet of the own node is temporarily transmitted until the user data packet with the bandwidth limit flag released is received from another node. Means for stopping automatically.

  According to the present invention, a control packet is preferentially transmitted, and when there is a user data packet transmission request during that time, the user data packet is buffered to temporarily wait for transmission. When there is a request to send a control packet, the relay packet is buffered and the control packet is sent by temporarily waiting for transmission, which is affected by the inflow of user data packets. The bandwidth for transferring the control packet can be guaranteed without any problem.

  In addition, when the bandwidth occupation amount such as the traffic amount on the transmission path side or the inflow amount of the user data packet from the terminal device of the own node exceeds a predetermined threshold, the user data packet from the terminal device of the own node is included in the header. When a user data packet with a bandwidth limit flag is transmitted from another node by adding a bandwidth limit flag, communication is performed by temporarily stopping transmission of the user data packet of the own node. Even when the bandwidth is congested when transferring user data packets during communication, the bandwidth limit flag is notified to other nodes, and the other nodes are encouraged to stop packet transmission to secure the bandwidth. It is possible to smoothly transfer packets during communication.

  FIG. 1 shows functional blocks of a packet relay device (LAN accommodating board) according to the present invention. In the same figure, the decelerator 1-1 has a function of converting a packet divided into 73 octet cells flowing from the transmission path into a continuous packet frame. In addition, it has a function of identifying whether an inflow packet is a reception cell received by its own node or a relay cell relayed to another node.

  The relay processing unit 1-2 has a function of buffering the relay cell transmitted from the decelerating unit 1-1. The packet cell unit 1-3 has a function of dividing a transmission packet into 73 octets and transmitting a cell generated by adding header information. Further, when the relay cell is buffered in the relay processing unit 1-2, the relay cell has a function of performing the priority processing described below and transmitting the relay cell.

  The timer 1-4 counts up the clock signal in order to detect the elapse of a predetermined time when receiving a packet having a band limit flag described later. The transmission packet selection unit 1-5 performs priority processing for preferentially transmitting the control packet to the control packet and the user data packet from the terminal device, and controls the control packet if there is a control packet. If there is no packet, the user data packet is sent to the packet cellization unit 1-3.

  The downlink CPU control packet interface 1-6 sends the control packet between the nodes received from the transmission path to the central processing unit (CPU) 1-7. The upstream CPU control packet interface 1-8 receives a control packet between nodes from the central processing unit (CPU) 1-7 and sends it to the transmission packet selection unit 1-5.

  The reception cell counter 1-9 counts the number of cells received from the transmission path and monitors the bandwidth usage. The downlink packet buffer control unit 1-10 controls buffering of user data packets received from the transmission path to the terminal device side. For the buffering, a memory 1-11 such as SDRAM can be used. The upper repacket buffer control unit 1-12 controls buffering of user data packets input from the terminal device to the transmission line side. For the buffering, a memory 1-13 such as SDRAM can be used.

  The terminal device transmission interface 1-14 converts the received user data packet into a data frame configuration on the terminal device side and sends it out. The terminal device reception interface 1-15 converts the user data packet input from the terminal device into a data frame configuration on the transmission path side and transmits it. The packet inflow monitoring unit 1-16 monitors the amount of packet inflow from the terminal device. The external line interface 1-17 has an interface function with the terminal device.

  The above-described nodes A to D of FIG. 8 constituting the ring type transmission apparatus are each equipped with a packet relay device (LAN accommodating board), and the bandwidth of the transmission path connecting the nodes A to D is determined by each network system. The user data packet and the control packet are shared and transferred by the packet relay apparatus (LAN accommodating board) of each node A to node D. At the time of packet transmission / reception between the node A and the node C, the node B and the node D process the incoming packet as a relay packet.

  The transmission packet selection unit 1-5 and the packet cellization unit 1-3 perform priority processing on the control packet, the relay packet, and the user data packet flowing in from the terminal device as follows. In the transmission packet selection unit 1-5, the control packet is transmitted with priority over the user data packet from the terminal device, and in the packet cellization unit 1-3, the control packet is transmitted with priority over the relay packet, and the relay packet is transmitted. Sends priority over user data packets.

  In the transmission packet selection unit 1-5 and the packet cellization unit 1-3 of each node, the control packet is transmitted to the transmission path with the highest priority, so that the control packet can be reliably transferred even during traffic congestion. The minimum bandwidth for transferring is guaranteed. FIG. 2 shows the above priority processing flowchart. In the figure, the flow in the block 2-1 surrounded by a broken line is a priority processing flow in the transmission packet selection unit 1-5, and the flow in the block 2-2 also surrounded by a broken line is the packet cellization unit 1- 3 is a flow of priority processing in FIG.

  Further, the packet relay apparatus (LAN accommodating board) monitors the use band by counting the number of packets (cells) received from the transmission path by the reception cell counter 1-9 and monitoring by the reception cell counter 1-9. When the number of cells exceeds 90% of the usable bandwidth and there is a control packet transmission request, the control unit (not shown) temporarily buffers user data packets from the terminal device and transmits the control packets. After that, the user data packet from the terminal device that has been buffered is transmitted. The above-mentioned value of 90% is a value given as an example, and this value can be appropriately determined according to the system.

  FIG. 3 shows a flowchart of the control packet priority process by monitoring the number of received packets (cells) described above. By performing such priority processing in each node, even when there is a control packet transmission request even during traffic congestion, after temporarily buffering the user data packet from the terminal device and transmitting the control packet, User data packets can be transmitted to guarantee the bandwidth of control packets, and user data packets can be transmitted without buffering during non-congestion, so that user data packets can be transmitted smoothly.

  Next, the bandwidth guarantee by monitoring the average used bandwidth on the transmission path side and the inflow from the terminal device side will be described. The received cell count 1-9 is used to monitor the average bandwidth on the transmission line side, and the packet inflow amount monitoring unit 1-16 monitors the inflow amount of user data packets from the terminal device side.

  When the sum of the average usage band on the transmission line side and the inflow from the terminal device side exceeds a predetermined set band, a user data packet with a band limit flag set in a part of the cell header is transmitted. When transmitting a packet with the band limit flag set, it is transmitted after confirming that a packet (cell) with a similar band limit flag is not received from another node.

  An example of the frame configuration of a packet (cell) with a band limit flag is shown in FIG. The configuration example of the frame shown in the figure is an Ether (registered trademark) frame. In such a frame, for example, a part of bits of the area for storing the “lifetime (LIFE)” of the cell header is assigned as a bit “WF” with a bandwidth limit flag, and when WF = 1, “bandwidth limit requested” When WF = 0, it can be configured to notify the presence / absence of a bandwidth limitation request as “no bandwidth limitation request”.

  A node that has transmitted a packet (cell) with a band limit flag monitors whether or not there is a predetermined or larger vacancy in the transmission path side band. The released user data packet is transmitted, and the normal operation is resumed. FIG. 5 shows an operation flowchart when transmitting a packet (cell) with a band limitation flag.

  FIG. 6 shows an operation flowchart of the first embodiment of the processing of the packet relay device (LAN accommodating board) that has received a packet (cell) with a band limitation flag. When a packet (cell) with a band limit flag is received, the user data packet flowing in from the terminal device is buffered, and transmission to the transmission path is interrupted.

  When the buffer overflows due to the above buffering, flow control is performed on the terminal device. At the same time when the buffering is started, the elapsed time is started to be counted by the timer 1-4, and when a packet (cell) with a bandwidth limit flag is received again before the predetermined predetermined elapsed time is counted up, the same applies. The buffering of the user data packet is continued, the timer 1-4 is initialized, and the count is started. After the timer 1-4 finishes counting up the predetermined elapsed time, it transmits a user data packet from the terminal device of its own node that has been buffered.

  Next, FIG. 7 shows an operation flowchart of the second embodiment of the processing of the packet relay apparatus (LAN accommodating board) that has received a packet (cell) with a band limitation flag. When a packet (cell) with a band limit flag is received, the user data packet flowing in from the terminal device is buffered, and transmission to the transmission path is interrupted.

  When the buffer overflows due to the above buffering, flow control is performed on the terminal device. At the same time as the start of buffering, it is monitored whether or not a packet with the bandwidth limit flag released is received. When a packet with the bandwidth limit flag released is received, it is received from the terminal device of the own node that has been buffered. Send user data packet.

  By performing these processes at each node, even when the bandwidth is congested when transferring the user data packet during communication that started communication, the bandwidth limit flag is notified to other nodes, and other nodes are notified. Thus, self-restraint of packet transmission can be promoted to secure a bandwidth, and packets in communication can be transferred smoothly.

It is a functional block diagram of the packet relay apparatus (LAN accommodating board) of this invention. It is a priority process flowchart of the control packet of this invention. It is a flowchart of the control packet priority process by monitoring the number of received packets (cells) according to the present invention. It is a figure which shows the example of a frame structure of the packet (cell) with a band limitation flag of this invention. It is an operation | movement flowchart at the time of transmission of the packet (cell) with a band limitation flag of this invention. It is an operation | movement flowchart of 1st Embodiment of a process of the packet relay apparatus which received the packet (cell) with a band limitation flag of this invention. It is an operation | movement flowchart of 2nd Embodiment of a process of the packet relay apparatus which received the packet (cell) with a band limitation flag of this invention. It is a figure which shows the structural example of the ring type transmission apparatus which is an application object of this invention.

Explanation of symbols

1-1 Decelization Unit 1-2 Relay Processing Unit 1-3 Packet Cellization Unit 1-4 Timer 1-5 Transmission Packet Selection Unit 1-6 Downlink CPU Control Packet Interface 1-7 Central Processing Unit (CPU)
1-8 Up CPU control packet interface 1-9 Receive cell counter 1-10 Down packet buffer control unit 1-11 Memory 1-12 Upper repacket buffer control unit 1-13 Memory 1-14 Terminal device transmission interface 1-15 Terminal Device reception interface 1-16 Packet inflow monitoring unit 1-17 External line interface

Claims (4)

For exchanging transmission control information between nodes, sharing user-band transmission bandwidth among multiple nodes, exchanging user data packets flowing from terminal devices accommodated in the own node, relay packets flowing from other nodes and relaying to other nodes In the packet relay device of each node in the ring type transmission device for transferring the control packet of
When there is a transmission request for the control packet, the control packet is transmitted with priority, and when there is a transmission request for the user data packet, the user data packet is buffered to temporarily wait for transmission. Control packet priority processing means;
When there is a transmission request for a relay packet, when there is no transmission request for the control packet, the relay packet is transmitted with priority over the user data packet, and when there is a transmission request for the control packet, the relay packet Relay packet priority processing means for buffering and temporarily waiting for transmission,
A packet relay device comprising:   Traffic volume monitoring means for monitoring the traffic volume on the transmission line side, and when detecting that the traffic volume exceeds a predetermined threshold, when there is a request for transmission of the control packet, the user data packet is buffered and transmitted. 2. The packet relay apparatus according to claim 1, further comprising control packet priority processing means for temporarily waiting for the packet and transmitting the control packet with priority. When the sum of the traffic amount on the transmission path side and the inflow amount of user data packets from the terminal device of the own node exceeds a predetermined threshold, a band limit flag is set in the header for the user data packet from the terminal device of the own node. A means for adding and transmitting;
3. The apparatus according to claim 1, further comprising means for temporarily stopping transmission of the user data packet of the own node for a predetermined time when the user data packet with the bandwidth limitation flag is received from another node. The packet relay device described in 1. When the sum of the traffic amount on the transmission path side and the inflow amount of user data packets from the terminal device of the own node exceeds a predetermined threshold, a band limit flag is set in the header for the user data packet from the terminal device of the own node. In addition, when the sum is equal to or less than a predetermined threshold, means for canceling the bandwidth limit flag in the header and transmitting the user data packet from the terminal device of its own node;
When the user data packet with the bandwidth limit flag is received from another node, the transmission of the user data packet of the own node is temporarily stopped until the user data packet with the bandwidth limit flag released is received from another node. The packet relay device according to claim 1, further comprising:

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