JP3995482B2 - Router that transmits flow control signals at high speed - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a router, and more particularly to a router that enables high-speed transmission of a flow control signal communicated inside the router.
[0002]
[Prior art]
FIG. 4 is a block diagram illustrating a configuration example of the conventional router 100. This router 100 is an edge router, for example, and has 8 ports # 0 to # 7. The router 100 includes a port unit (LAN port unit) 110 corresponding to each of the ports # 0 to # 7. ₀ ~ 110 ₇ Port part 110 ₀ ~ 110 ₇ And a core switch 130 that performs switching of IP packets (or frames) therebetween.
[0003]
Port part 110 ₀ ~ 110 ₇ Have the same configuration, one port unit 110 _i The explanation will be given by taking (i is an integer of 0 to 7) as an example.
[0004]
Port part 110 _i L1 / L2 processing unit 111 (for example, PHY / MAC), L3 processing unit 112 (L3 Logic), reception queue management unit 113 (QMLR: Queue Management Logic on Receiver), buffer control unit 114 (for example, DBC: Double Buffer Controller) ), RAM 115, FDC (Frame Divide Controller) 116, FIFOs 117 and 119, transceiver 118, and L3 control unit 120 (LC: L3-Logic Controller).
[0005]
In the figure, the solid line indicates the flow of the packet (frame), and the broken line indicates the flow of the flow control signal (back pressure signal). The alternate long and short dash line indicates the flow of the control signal.
[0006]
A communication cable (for example, an Ethernet cable such as 10Base-T or 100Base-T) is attached to the L1 / L2 processing unit 111, and other routers, terminals, and the like are connected via the communication cable. The L1 / L2 processing unit 111 performs protocol processing of layer 1 (physical layer) and layer 2 (data link layer), and sends packets given from the L3 processing unit 112 to other routers, terminals, etc. via communication cables. And the packet received from another router, terminal or the like is given to the L3 processing unit 112.
[0007]
The L3 processing unit 112 performs protocol processing of layer 3 (network layer), gives a packet from the L3 control unit 120 to the L1 / L2 processing unit 11, and sends a packet from the L1 / L2 processing unit 111 to the buffer control unit 114. To give. Specifically, the L3 processing unit 112 analyzes the packet, determines the destination (destination) port number based on the routing table, gives the packet to the subsequent block 200, and also transmits the IP / MAC filtering and VLAN (virtual LAN tag operation, etc.) are performed.
[0008]
The buffer control unit 114 writes the packet given from the L3 processing unit 112 to the RAM 115 under the control of the reception queue management unit 113. The address of the RAM 115 where the packet is written is given from the buffer control unit 114 to the reception queue management unit 113.
[0009]
When instructed by the reception queue management unit 113, the FDC 116 reads the packet from the address of the RAM 115 and gives the packet to the transceiver 118 via the FIFO 117.
[0010]
The transceiver 118 is connected to another port unit 110 via the core switch 130. _j Arbitration is performed with the transceiver 118 (j is an integer from 0 to 7, including the case of i = j). Other port part 110 _j If the packet can be accepted, the port unit 110 of the arbitration partner _i ACK signal is returned to the transceiver 118.
[0011]
Port part 110 _i The transceiver 118 of the port unit 110 that has returned the ACK signal. _j In addition, the port section 110 _j Is sent through the core switch 200 as a destination port.
[0012]
Port part 110 _j The packet given to the transceiver 118 of the _j Are transmitted to other routers or terminals via the FIFO 119, the L3 control unit 120, the L3 processing unit 112, and the L1 / L2 processing unit 111.
[0013]
The L1 / L2 processing unit 111, the L3 processing unit 112, the buffer control unit 114, the FDC 116, the transceiver 118, and the L3 control unit 120 have a transmission side buffer and a reception side buffer (not shown) inside. The transmission side buffer is a buffer that temporarily stores a packet given to a subsequent apparatus, and the reception side buffer is a buffer that temporarily stores a packet given from the preceding apparatus.
[0014]
The L1 / L2 processing unit 111, the L3 processing unit 112, the buffer control unit 114, the FDC 116, the transceiver 118, and the L3 control unit 120 have a predetermined amount (threshold value) of the amount of packets stored in each reception side buffer. If it exceeds (that is, if the receiving buffer may overflow), the flow control signal instructs the adjacent device in the previous stage to stop packet transmission.
[0015]
Similarly, when the amount of data stored in its own memory exceeds the threshold value, the FIFOs 117 and 119 also instruct the adjacent devices in the previous stage to stop transmitting data by a flow control signal.
[0016]
For example, the port part 110 _j When the L1 / L2 processing unit 111 of the L1 / L2 processing unit 111 becomes unable to transmit a packet to another router, terminal, or the like connected to itself via a communication cable, the receiving side buffer (from the L3 processing unit 112) (A buffer for temporarily storing the packet) is accumulated in the packet from the L3 processing unit 112, and the accumulated amount eventually exceeds a predetermined threshold. At this time, the L1 / L2 processing unit 111 gives a flow control signal for stopping transmission to the L3 processing unit 112.
[0017]
When transmission of a packet from the L3 processing unit 112 to the L1 / L2 processing unit 111 is stopped, the amount of data stored in the reception side buffer (a buffer for temporarily storing data from the L3 control unit 120) of the L3 processing unit 112 Exceeds the threshold, and the L3 processing unit 112 transmits a flow control signal for stopping transmission to the L3 control unit 120.
[0018]
In this way, the flow control signal for stopping transmission is given to the transceiver 118 in a chain.
[0019]
When the transceiver 118 receives the flow control signal for stopping transmission, the transceiver unit 110 performs the arbitration process to perform the port unit 110. _i Stop accepting packets from other ports (ie, other port units 110 _i ACK signal is not returned to
[0020]
Port part 110 _i Also in port 110 _j When the packet cannot be transmitted to the port unit 110, the reception buffer of each component may eventually overflow, and the port unit 110 _i A flow control signal for stopping transmission is passed from the transceiver 118 to the L1 / L2 processing unit 11.
[0021]
In this way, the transmission stop is transmitted in a chain by a flow control signal in a certain port unit, is transmitted to the other port unit through arbitration between the transceiver 118 and the core switch 130, and is again flowed in the other port unit. Chained by control signals.
[0022]
Port part 110 _i Same port part 110 from _i Similarly, a flow control signal for stopping the transmission of the packet given to is also given via the core switch 130.
[0023]
[Problems to be solved by the invention]
As described above, in the conventional router, the flow control signal for stopping transmission is transmitted via the core switch 130.
[0024]
Therefore, in a conventional router, a certain port unit 110 _j When there is a possibility that the receiving side buffer of the constituent elements (L1 / L2 processing unit 111, L3 processing unit 112, etc.) may overflow, other port unit 110 serving as the transmission source _i It took a lot of time to stop sending.
[0025]
In addition, in the conventional router, the time for transmitting the flow control signal to each port portion varies.
[0026]
The present invention has been made in view of such a situation, and an object of the present invention is to transmit a flow control signal to other port portions at high speed.
[0027]
Another object of the present invention is to reduce the time difference (variation) in the transmission of the flow control signal to each port.
[0028]
[Means for Solving the Problems]
In order to achieve the above object, a router according to the present invention is a router having a plurality of ports, wherein a plurality of packets are individually processed for each port for packets input from and output from each of the plurality of ports. A plurality of port processing means, a switch means for switching the packets between the plurality of port processing means, and a communication line connecting the plurality of port processing means. Each transmitting a flow control signal indicating permission or stop of transmission of a packet given to itself via the switch means to the plurality of port processing means via the communication line; Features.
[0029]
According to the present invention, a communication line for connecting a plurality of port processing means is provided, and a flow control signal is transmitted through the communication line. Therefore, the flow control signal can be transmitted to other port portions at a higher speed than the conventional router in which the flow control signal is transmitted indirectly through the switch means.
[0030]
Preferably, the communication line individually connects the plurality of port processing means on a one-to-one basis, and each of the plurality of port processing means transmits the flow control signal to the plurality of port processing means simultaneously. As a result, the time difference (variation) in the transmission of the flow control signal to each port can be eliminated (or reduced).
[0031]
More preferably, each of the plurality of port processing means processes the flow control signal transmitted to itself within itself without going through the communication line. As a result, the flow control signal addressed to its own port is returned inside itself, and the flow control transmission / reception device addressed to itself can be made the same as that of the other port.
[0032]
In an embodiment of the present invention, the packet has a plurality of classes indicating transmission priorities, and the flow control signal indicates transmission permission or transmission stop for each class.
[0033]
In another embodiment, each of the plurality of port processing means includes a determining means for determining a destination port of a packet input via the port, and a port of a destination port of the packet via the switch means. Arbitration means for arbitrating with the processing means, and based on the result of the arbitration, the arbitration means for giving a packet to the destination port via the switch means, and the packet given from the determination means are received, and the format of the packet is input to the arbitration means Format conversion means for converting to a format suitable for the mediation means and giving to the arbitration means, the communication line connecting the format conversion means of the plurality of port processing means, the flow control signal, It is transmitted by the format conversion means.
[0034]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a block diagram showing a configuration of a router 1 according to an embodiment of the present invention. The router 1 is a router having eight ports (LAN ports) # 0 to # 7. Other routers, terminals, etc. are connected to each port.
[0035]
The router 1 includes a line termination module (LTM) 3 ₀ ~ 3 ₇ Switch blade device (SWB) 4 ₀ ~ 4 ₇ , CSIX Bridge Device (CSB: CSIX Bridge) 5 ₀ ~ 5 ₇ , Transceiver 6 ₀ ~ 6 ₇ , And a core switch 8.
[0036]
LTM3 ₀ ~ 3 ₇ All have the same configuration. Similarly, SWB4 ₀ ~ 4 ₇ , CSB5 ₀ ~ 5 ₇ , And transceiver 6 ₀ ~ 6 ₇ Each have the same configuration.
[0037]
Figure 2 shows CSB5 _i It is a block diagram which shows the detailed structure of (i is an integer in any one of 0-7, and so on).
[0038]
CSB5 _i Includes a control unit 50, a packet processing unit 60, and an FCD processing unit 70. The packet processing unit 60 includes format conversion units 61 and 62, a SWB side packet receiving unit 63, a SWB side packet transmitting unit 65, a transceiver side packet transmitting unit 64, and a transceiver side packet receiving unit 66. The FCD processing unit 70 includes a SWB side FCD transmission unit 71, a SWB side FCD reception unit 72, a transceiver side FCD reception unit 73, a transceiver side FCD transmission unit 74, a CSB side FCD reception unit 75, and a CSB side FCD transmission unit 76. .
[0039]
In the figure, a solid line indicates a signal line through which an IP packet or data obtained by converting the format of the IP packet is transmitted and received, and a broken line indicates a signal line through which a flow control signal (flow control data (FCD)) is transmitted and received. ing. A one-dot chain line indicates a signal line for transmitting / receiving a control signal to / from the control unit 50.
[0040]
Port #i has LTM3 _i , SWB4 _i , CSB5 _i , And transceiver 6 _i These form a port unit that executes packet processing in units of ports. The number of ports 8 is an example, and other numbers of ports (for example, 4, 16, 32 ports, etc.) may be used.
[0041]
CSB5 ₀ ~ 5 ₇ , Transceiver 6 ₀ ~ 6 ₇ , And the block 2 composed of the core switch 8 corresponds to the conventional block 200.
[0042]
In the router 1 having such a configuration, IP packet processing (routing processing, etc.) will be described first.
[0043]
LTM3 _i A communication cable (for example, an Ethernet cable such as 10Base-T or 100Base-T) is attached. LTM3 _i Is connected to other routers, terminals, etc. via this communication cable. This LTM3 _i Has a line termination function and executes predetermined protocol processing of layer 1 (physical layer) and layer 2 (data link layer) on IP packets transmitted from other routers or the like. After predetermined protocol processing, LTM3 _i Sends the IP packet to SWB4 _i To give.
[0044]
SWB4 _i Is LTM3 _i Has an LTM side buffer for temporarily storing the IP packet given from, and stores the IP packet in this LTM side buffer. SWB4 _i Holds the routing table, and based on the destination address (IP address or MAC (Media Access Control) address) of the IP packet stored in the LTM side buffer and the routing table, which port (destination port, transmission) To give to the destination port).
[0045]
After determining the destination port, SWB4 _i Divides an IP packet into data of a predetermined length (hereinafter, simply referred to as “packet”), and divides the packet into CBS5 _i Is stored in a buffer (CBS side buffer) provided in the crocodile.
[0046]
This CBS side buffer is CSB5 _i Is temporarily stored, and is divided into eight buffers respectively corresponding to destination ports # 0 to # 7. A CSB-side transmission buffer for storing packets transmitted from the own port #i to the own port #i is also provided.
[0047]
Each of the eight CSB side transmission buffers is further divided for each packet priority (class). For example, when eight classes of classes 0 to 7 are provided in the priority order, each CSB side transmission buffer is divided into eight buffers (hereinafter referred to as “divided buffers”).
[0048]
Then, based on the destination port and the priority order, the packet is stored in the divided buffer of the CSB side transmission buffer corresponding to the destination port and the priority order, and then transmitted.
[0049]
SWB4 _i And CSB5 _i In the present embodiment, a CSIX interface is used for the interface between and. Meanwhile, CSB5 _i And transceiver 6 _i An interface different from the CSIX interface is used. Therefore, CSB5 _i SWB4 _i A packet (a packet having a format defined by the CSIX interface) given by CSB5 _i And transceiver 6 _i The packet is converted into a packet having a format defined by the interface between the transceiver 6 and the packet after the format conversion is converted to the transceiver 6. _i To give.
[0050]
Specifically, referring to FIG. _i SWB side packet receiving unit 63 of SWB4 _i The packet transmitted from (the IP packet is divided) is received. The SWB side packet receiving unit 53 has eight buffers respectively corresponding to the destination ports # 0 to # 7, and each of the eight buffers is a divided buffer corresponding to each of the classes 0 to 7 which are packet priorities. It is divided into
[0051]
Then, the SWB side packet receiver 63 receives the SWB4 _i Are stored in the division buffer corresponding to the destination port and priority. For example, SWB4 _i When the packet transmitted from the destination port j (j is an integer of 0 to 7, including the case of i = j; the same applies hereinafter) and the priority is m, this packet is SWB The packet is stored in the division buffer corresponding to the destination port j and priority m in the side packet receiving unit 53.
[0052]
The format conversion unit 61 reads the packet stored in the SWB side packet reception unit 63 under the control of the control unit 50, and converts the format of this packet (that is, the format of the CSIX interface) to the transceiver 6. _i The converted packet is sent to the transceiver-side packet transmitter 64.
[0053]
The transceiver-side packet transmission unit 64 stores the packet given from the format conversion unit 61 in an internal buffer, and under the control of the control unit 50, the transceiver 6 _i Send to. The internal buffer of the transceiver side packet transmission unit 64 is constituted by, for example, a FIFO. The transceiver side packet transmission unit 64 sequentially reads out the packets stored in the internal buffer in the order of writing, and the transceiver 6 _i Send to.
[0054]
Returning to FIG. _i Is sent through the core switch 8 to the transceivers 6 of all ports #j. _j (Self transceiver 6 _i And arbitration with all other transceivers 6). As a result of the arbitration process, transceiver 6 _i Is transceiver 6 _j When the ACK signal is received from the packet, the packet having the destination port #j is switched by the core switch 8 and the transceiver 6 _i To transceiver 6 _j Given to. The core switch 8 is constituted by a crossbar switch, for example, and performs packet switching processing between transceivers (ports).
[0055]
Transceiver 6 _j Sends the packet given through the core switch 8 to the CSB 5 _j To give.
[0056]
Turning to FIG. 2, CSB5 _j The transceiver-side packet receiving unit 66 has an internal buffer configured by, for example, a FIFO. Then, the transceiver side packet receiving unit 66 is connected to the transceiver 6. _j Are sequentially stored in this internal buffer in the order received.
[0057]
The format conversion unit 62 performs the reverse process of the format conversion unit 61. That is, the format conversion unit 62 controls the format of the packet stored in the transceiver side packet receiving unit 66 (that is, the transceiver 6) under the control of the control unit 50. _j Is converted into the format of the CSIX interface, and the converted packet is given to the SWB side packet transmitter 65.
[0058]
The SWB side packet transmission unit 65 has an internal buffer, and this internal buffer is divided into divided buffers corresponding to the priority order. The format conversion unit 62 stores the converted packet in a division buffer corresponding to the priority order of the packet.
[0059]
The packet stored in the SWB side packet transmitter 65 is controlled by the control unit 50 under the control of the SWB 4 _j Sent to.
[0060]
Returning to FIG. 1, SWB4 _j Is CSB5 _j Has an internal buffer (CSB side reception buffer) for storing packets transmitted from. The CSB side reception buffer is divided into divided buffers corresponding to the priority order.
[0061]
SWB4 _j Is CSB5 _j Is stored in the division buffer corresponding to the priority order in the CSB side reception buffer, and the stored packets are assembled into one IP packet, and the LTM3 _j To give.
[0062]
LTM3 _j SWB4 _j An internal buffer for temporarily storing IP packets given by LTM3 _j Performs predetermined protocol processing on the IP packet stored in the internal buffer, and transmits the IP packet to another router or the like via a communication cable.
[0063]
As described above, the IP packet transmitted from port #i to port #i is also LTM3. _i To SWB4 _i To the core switch 8 and the transceiver 6 again from the core switch 8 _i Etc. via LTM3 _i To be sent.
[0064]
Next, FCD processing for controlling packet transmission permission or stop in the router 1 will be described.
[0065]
LTM3 _i And SWB4 _i FCDs that control permission or stop of transmission / reception of IP packets are exchanged. SWB4 _i And CSB5 _i And CSB5 _i And transceiver 6 _i FCDs are exchanged between the two. Furthermore, in this embodiment, CSB5 _i And other CSB5 _k FCD is also exchanged between (k is an integer from 0 to 7 excluding i, and so on).
[0066]
LTM3 _i And SWB4 _i The FCD exchanged with each other is a level signal, a low level means transmission permission, and a high level means transmission stop.
[0067]
As mentioned above, LTM3 _i Is SWB4 _i Has an internal buffer for storing IP packets from. If the amount of data stored in the internal buffer exceeds a predetermined threshold (that is, the internal buffer may overflow), the LTM3 _i Is LTM3 _i To SWB4 _i FCD is set to a high level (transmission stopped), and if the amount of data is below a predetermined threshold, the FCD is set to a low level (transmission permitted).
[0068]
SWB4 _i Is LTM3 _i When FCD from is low level, LTM3 _i When the IP packet is transmitted to the FCD and the FCD is at the high level, the LTM3 _i Stop sending IP packets to
[0069]
Similarly, SWB4 _i When the amount of data stored in the LTM side buffer exceeds a predetermined threshold, SWB4 _i SWB4 _i To LTM3 _i The FCD is set to the high level, and when the data amount is equal to or less than the predetermined threshold, the FCD is set to the low level. Corresponding to the high level or low level of this FCD, SWB4 _i Is LTM3 _i IP packet transmission to or stop transmission.
[0070]
SWB4 _i And CSB5 _i The FCD exchanged with is performed with data having a format defined in the CSIX interface. This data includes data indicating transmission permission or transmission stop.
[0071]
SWB4 _i Monitors the amount of packets stored for each division buffer of the CSB side reception buffer, and sets FCD indicating transmission permission or transmission stop of packets of priority order corresponding to each division buffer to CSB5 _i Send to.
[0072]
3 shows SWB4 _i To CSB5 _i Shows the format of the FCD to be transmitted. The FCD has a field corresponding to each priority (class) 0 to 7 (when eight priority levels are provided) and a field of check bits (for example, parity bits).
[0073]
In each field corresponding to each class 0 to 7 of the priority order, a value indicating permission or stop of transmission of the packet of each priority order is stored. For example, each field has 4 bits, and when all 4 bits are 0, it means transmission permission of a packet having a priority corresponding to that field. When all 4 bits are 1, the field This means that transmission of a packet having a priority order corresponding to is stopped. This FCD may be transmitted continuously without interruption, or may be transmitted at regular time intervals.
[0074]
SWB4 _i When the packet amount of each division buffer of the CSB side reception buffer exceeds a predetermined threshold (that is, there is a possibility that the division buffer overflows), the field of the class corresponding to this division buffer is stopped, and the amount of packets is If the value is equal to or less than the predetermined threshold, the field of the corresponding class is permitted to be transmitted.
[0075]
This FCD is CSB5 _i Is provided to the SWB side FCD receiver 72. The SWB side FCD receiving unit 72 is connected to the SWB4 _i When the FCD is received, the FCD is given to the CSB side FCD transmission unit 76 via the control unit 50 (or directly without going through the control unit 50).
[0076]
The CSB side FCD transmission unit 76 has the same number of output signal lines as the number of other CSBs (seven in the present embodiment), and each output signal line is individually connected to another CSB. For example, CSB5 ₀ The first output signal line at the left end of the CSB side FCD transmitter 76 is CSB5. ₁ The second output signal line is CSB5. ₂ ..., the seventh output signal line is CSB5. ₇ Are connected to each. Other CSB5 ₁ ~ 5 ₇ The same applies to the CSB-side FCD transmission unit 76.
[0077]
CSB4 _i The CSB-side FCD transmitter 76 of the seven output terminals continuously or intermittently outputs an FCD having the same format as that shown in FIG. 3 (hereinafter referred to as “inter-CSB FCD”) from all seven output terminals. Send at time intervals. The contents (transmission permission or transmission stop) of each field of the inter-CSB FCD are the same as the contents of each field of the FCD given from the SWB side FCD receiving unit 72.
[0078]
The transmission of FCD between CSBs can be performed with a time difference for each output signal line, but it is preferable to perform the transmission simultaneously. By transmitting at the same time, the inter-CSB FCD is simultaneously received by other CSBs, and variations in reception time can be eliminated.
[0079]
The inter-CSB FCD is input to the CSB side FCD receiving unit 75 of all other CSBs.
[0080]
The CSB side FCD receiving unit 75 has the same number of input signal lines as the number of other CSBs (seven in the present embodiment).
[0081]
Each input signal line is individually connected to the CSB side FCD transmission unit 76 of another CSB. For example, CSB5 ₁ CSB side FCD receiver 75 has seven input terminals, and the leftmost first input signal line is CSB5. ₀ The second input signal line is CSB5. ₂ ..., the seventh input signal line is CSB5. ₇ Are connected to each. Other CSB5 ₀ , 5 ₂ ~ 5 ₇ The same applies to.
[0082]
The CSB side FCD receiving unit 75 identifies the CSB (that is, the port number) that transmitted the inter-CSB FCD by the input terminal that has received the inter-CSB FCD. That is, according to the above example, the inter-CSB FCD input from the first input signal line is expressed as CSB5. ₀ (I.e. from port # 0).
[0083]
When the received CSB FCD includes a class (priority order) indicating transmission stop, the CSB-side FCD receiving unit 75 transmits the CSB inter-CSB FCD (referred to as port #n) and the port. An instruction to stop transmission of a class (class m) packet is sent via the control unit 50 (or directly without going through the control unit 50) to the SWB side FCD transmission unit 71 and the format conversion unit 11 (or SWB). Side packet receiver 63 and transceiver side packet transmitter 64).
[0084]
SWB side FCD transmitter 71 (CSB5 _k The SWB side FCD transmission unit 71 of FIG. ) Receives the transmission stop command, SWB4 sets the FCD indicating the transmission stop of the packet with the priority m of the destination port #n. _k Send to. As a result, SWB4 _k Is the destination port n and the CSB5 of the packet with the priority m _k Stop sending to.
[0085]
Also, the format conversion unit 11 (or SWB side packet receiving unit 63, transceiver side packet transmitting unit), among the packets stored in the SWB side packet receiving unit 63, is a transceiver 6 for packets of destination port n and priority m. _k Stop sending to.
[0086]
Transmission of a port other than the destination port n or a packet other than the priority order m is permitted.
[0087]
CSB5 _i CSB side FCD transmission unit 76 of the same CSB5 _i The FCD is also given to the CSB side FCD receiving unit 75. This FCD is CSB5 _i Is provided with a signal line (not shown) for directly connecting the CSB side FCD transmission unit 76 and the CSB side reception unit 75, and can be given by this signal line or can be given via the control unit 50. .
[0088]
As a result, CSB5 _i SWB side FCD transmitter 71 to SWB4 _i FCD indicating transmission stop of the packet with the priority m of destination port #n is transmitted to SWB4 _i Stops sending the packet. Also, CSB5 _i Transmission of the same packet from the format converter 61 to the transceiver 6i is stopped.
[0089]
In this way, the FCD is given to the CSB via a communication line (communication network) that directly connects the CSBs to one pair without intermediation between the transceiver 6 and the core switch 8, so The command can be transmitted at high speed, and the transmission can be stopped quickly.
[0090]
SWB5 _i And transceiver 6 _i FCDs are also exchanged between This FCD is a level signal, a low level means transmission permission, and a high level means transmission stop.
[0091]
The control unit 50 monitors the amount of packets stored in the transceiver side packet receiving unit 66, and if this amount exceeds a predetermined threshold (that is, the buffer may overflow), the control unit 50 outputs from the transceiver side FCD transmission unit 74. The FCD to be performed is set to the ash level, and if it is equal to or lower than the predetermined threshold, it is set to the low level.
[0092]
Transceiver 6 _i Is CSB5 _i When the FCD is low, the packet is transmitted. When the FCD is high, the packet transmission is stopped.
[0093]
Similarly, transceiver 6 _i Also, CSB5 _i If there is a possibility that the buffer for temporarily storing packets transmitted from the network may overflow, CSB5 _i If there is no possibility of overflow, the FCD is set to a low level.
[0094]
Transceiver 6 _i Transceiver side FCD receiver 73 of transceiver 6 _i When the FCD from the receiver goes to the high level, the format converter 61 (or SWB side packet transmitter 63, transceiver side packet transmitter 64) is connected to the transceiver via the controller 50 (or directly without the controller 50). 6 _i Command to stop sending packets to As a result, the transceiver 6 _i Transmission of packets to is stopped.
[0095]
(Appendix 1) In a router having multiple ports,
A plurality of port processing means for individually processing a packet input from each of the plurality of ports and a packet output from each of the ports;
Switch means for switching the packet between the plurality of port processing means;
A communication line connecting the plurality of port processing means;
Have
Each of the plurality of port processing means transmits a flow control signal indicating permission or stop of transmission of a packet given to itself via the switch means to the plurality of port processing via the communication line. Send to means,
A router characterized by that.
[0096]
(Appendix 2) In Appendix 1,
The communication line individually connects the plurality of port processing means on a one-to-one basis,
Each of the plurality of port processing means simultaneously transmits the flow control signal to the plurality of port processing means;
A router characterized by that.
[0097]
(Appendix 3) In Appendix 1 or 2,
Each of the plurality of port processing means processes the flow control signal transmitted to itself within itself without going through the communication line.
A router characterized by that.
[0098]
(Appendix 4) In any one of Appendices 1 to 3,
The packet has a plurality of classes representing transmission priorities,
The flow control signal indicates transmission permission or transmission stop for each class,
A router characterized by that.
[0099]
(Appendix 5) In any one of Appendices 1 to 4,
Each of the plurality of port processing means includes:
Determining means for determining a destination port of a packet input through the port;
Arbitrating with the port processing means of the destination port of the packet via the switch means, and arbitrating means for giving the packet to the destination port via the switch means based on the arbitration result;
Receiving the packet given from the determining means, converting the format of the packet into a format suitable for the input of the arbitrating means, and providing the format converting means to the arbitrating means,
The communication line connects between the format conversion means of the plurality of port processing means,
The flow control signal is transmitted by the format conversion means.
A router characterized by that.
[0100]
(Appendix 6) In Appendix 5,
The arbitration unit receives a packet from the arbitration partner arbitration unit via the switch unit, and gives the received packet to the format conversion unit.
The format conversion means converts the format of the packet given from the arbitration means into a format suitable for the input of the decision means, and gives the decision means,
The determination means includes a storage means for transmitting the packet given from the format conversion means toward the port and temporarily storing the packet given from the format conversion means, and the storage means overflows. If there is a fear, the format conversion means is instructed to stop sending packets to itself,
The format conversion means transmits the flow control signal indicating transmission stop for a packet addressed to the port processing means to which the determination means and the format conversion means belong, based on a transmission stop instruction from the determination means.
A router characterized by that.
[0101]
【The invention's effect】
According to the present invention, flow control signals can be transmitted to other port portions at high speed. Further, according to the present invention, it is possible to reduce (or eliminate) the time difference (variation) in transmission of the flow control signal to each port part.
[Brief description of the drawings]
FIG. 1 is a block diagram showing a configuration of a router according to an embodiment of the present invention.
FIG. 2 is a block diagram showing a detailed configuration of a CSB.
FIG. 3 shows a format of flow control data transmitted / received between CSBs.
FIG. 4 is a block diagram illustrating a configuration example of a conventional router 100.
[Explanation of symbols]
1 router
3 ₀ ~ 3 ₇ Line termination module (LTM)
4 ₀ ~ 4 ₇ Switch blade device (SWB)
5 ₀ ~ 5 ₇ CSIX bridge device (CSB)
6 ₀ ~ 6 ₇ Transceiver
8 core switches
71 SWB side FCD transmitter
72 SWB side FCD receiver
75 CSB side FCD receiver
76 CSB side FCD transmitter

Claims (5)

In a router with multiple ports,
A plurality of port processing means for individually processing a packet input from each of the plurality of ports and a packet output from each of the ports;
Switch means for switching the packet between the plurality of port processing means;
A communication line connecting the plurality of port processing means;
Have
Each of the plurality of port processing means transmits a flow control signal indicating permission or suspension of transmission of a packet given to itself via the switch means to the plurality of port processing via the communication line. To the means,
Each of the plurality of port processing means includes a switch blade that determines the port to which the input packet is transmitted, and a bridge that converts the format of the input packet output from the switch blade. The flow control signal is also transmitted between the blade and the bridge,
A router characterized by that. In claim 1,
The communication line individually connects the plurality of port processing means on a one-to-one basis,
Each of the plurality of port processing means simultaneously transmits the flow control signal to the plurality of port processing means;
A router characterized by that. In claim 1 or 2,
Each of the plurality of port processing means processes the flow control signal transmitted to itself within itself without going through the communication line.
A router characterized by that. In any one of Claims 1-3,
The packet has a plurality of classes representing transmission priorities,
The flow control signal indicates transmission permission or transmission stop for each class,
A router characterized by that. In any one of Claims 1-4,
Each of the plurality of port processing means includes:
The switch blade for determining a destination port of a packet input through the port;
Arbitrates with the port processing means of the destination port of the packet via the switch means,
Arbitration means for providing a packet to the destination port via the switch means based on the arbitration result;
Receiving the packet given from the switch blade , converting the format of the packet into a format suitable for the input of the arbitration means, and providing the bridge to the arbitration means,
The communication line connects between the bridges of the plurality of port processing means,
The flow control signal is transmitted by the bridge ;
A router characterized by that.

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