Packet forwarding apparatus with transmission control function

Abstract

A packet forwarding apparatus 200 transmits an inputted packet A to a first output port that is one of a plurality of output ports and transmits a dummy packet A storing the packet length of packet A to the other output port. A shaping unit 100-1 corresponding to the first output port uses the packet length of the packet A and a shaping unit 100-2 corresponding to the port other than the first output port uses a packet length in the dummy packet A so as to control the bandwidth of the packet A to be transmitted, thus controlling the total bandwidth of the packet A.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings,

FIG. 1 is a block diagram of a shaping unit 100;

FIG. 2 is a block diagram of a packet forwarding apparatus 200;

FIG. 3 is an illustration showing an example of the format of a packet transmitted and received by the packet forwarding apparatus 200;

FIG. 4 is an illustration showing an example of the format of a packet in the packet forwarding apparatus 200;

FIG. 5 is a block diagram of a packet receiving unit 230;

FIG. 6 is an illustration showing an example of the format of an MPLS packet transmitted and received by the packet forwarding apparatus 200;

FIG. 7 is an illustration showing an example of the format of an MPLS packet in the packet forwarding apparatus 200;

FIG. 8 is a block diagram of a packet transmission unit 240;

FIG. 9 is an illustration showing times when shaping units 100-1 and 100-2 transmit packets;

FIG. 10 is a block diagram of a route decision unit 221;

FIG. 11 is an illustration showing an example of the structure of an output port number table 820;

FIG. 12 is an illustration showing an example of the structure of an output port/output label number table 1920;

FIG. 13 is a block diagram of a packet write unit 130;

FIG. 14 is an illustration showing times when the shaping units 100-1 and 100-2 transmit packets;

FIG. 15 is a block diagram of a packet read unit 150;

FIG. 16 is an illustration showing an example of the structure of a packet transmission control table 1120;

FIG. 17 is an illustration showing an example of the structure of a bandwidth information storing unit 1140;

FIG. 18 is a flowchart of the packet read unit 150;

FIG. 19 is an illustration showing an example of the structure of the bandwidth information storing unit 1140;

FIG. 20 is a block diagram of a bandwidth policing unit 2000;

FIG. 21 is an illustration showing an example of a bandwidth policing table 2030;

FIG. 22 is a flowchart of the bandwidth policing unit 2000;

FIG. 23 is an illustration showing an example of the commands for setting up the bandwidth information storing unit 1140; and

FIG. 24 is an illustration showing an example of the commands for setting up the bandwidth policing table 2030.

Claims

1. A packet forwarding apparatus for determining a plurality of input ports, a plurality of output ports, and an output port group composed of at least one output port from information in a header of a packet and transmitting a packet from either of a first output port and a second output port included in the output port group, the packet forwarding apparatus comprising: a transmission control unit for controlling a bandwidth of the second output port included in the output port group, using a packet length of a first packet that is transmitted from the first output port included in the output port group.

2. The packet forwarding apparatus according to claim 1, wherein using a class of the first packet, the transmission control unit controls a bandwidth of the second output port for each class.

3. The packet forwarding apparatus according to claim 1, further comprising a packet receiving unit for creating a dummy packet for storing information indicating the packet length of the first packet and transmitting the dummy packet to the transmission control unit.

4. The packet forwarding apparatus according to claim 3, wherein the transmission control unit includes a filter unit for discarding the dummy packet.

5. The packet forwarding apparatus according to claim 1, wherein the output port group corresponds to a plurality of output ports aggregated by link aggregation or an output port for accommodating a protected LSP of MPLS and an output port for accommodating a backup LSP corresponding to the protected LSP.

6. A packet forwarding apparatus for receiving a packet from a plurality of input ports and transmitting a packet from a plurality of output ports, the packet forwarding apparatus comprising: a route decision unit for determining a transfer destination of a received packet, based on header information of the received packet; anda receiving unit for, if the route decision unit determines that a first output port out of an output port group composed of a plurality of output ports is a transfer destination of a first packet, transferring the first packet to a first transmission unit corresponding to the first output port and transmitting a notification of a packet length of the first packet to a second transmission unit corresponding to a second output port other than the first output port out of the output port group.

7. The packet forwarding apparatus according to claim 6, wherein the receiving unit transmits the notification of the packet length, using a dummy packet containing information indicating the packet length.

8. The packet forwarding apparatus according to claim 6, wherein the notification of the packet length of the first packet by the receiving unit includes information indicating a class of the first packet.

9. The packet forwarding apparatus according to claim 6, wherein the route decision unit includes a routing table search unit for determining an output port group, based on header information of the received packet, anda control unit for determining an output port of a transfer destination out of output ports included in the output port group determined by the routing table search unit and determining that an output port other than the output port of the transfer destination determined out of output ports included in the output port group determined by the routing table search unit is a notification destination of a packet length.

10. The packet forwarding apparatus according to claim 9, wherein the route decision unit includes an output port table for associating a plurality of output ports with an output port group or an output label table for associating a plurality of output labels with an output port group.

11. The packet forwarding apparatus according to claim 6, wherein the first and second transmission units include a bandwidth control unit for controlling transmission of a packet, based on the packet and the notification of the packet length that are received from the receiving unit.

12. The packet forwarding apparatus according to claim 7, wherein the bandwidth control unit includes a queue for storing a packet and a dummy packet received from the receiving unit, anda packet write unit for counting the number of packets and dummy packets to be written into the queue, comparing the counted number of packets and dummy packets with a threshold, and discarding the packets and dummy packets to be written if the counted number of packets and dummy packets exceeds the threshold.

13. The packet forwarding apparatus according to claim 7, wherein the bandwidth control unit includes a queue for storing a packet and a dummy packet received from the receiving unit, anda packet read unit for determining a timing for reading a packet and a dummy packet from the queue, based on information indicating a packet length stored in the packet and the dummy packet and a set bandwidth.

14. The packet forwarding apparatus according to claim 7, wherein the bandwidth control unit includes a storage unit for storing a packet and a dummy packet received from the receiving unit,a packet arrival history storing unit for storing packet arrival history information corresponding to a packet length of a packet and a dummy packet last stored in the storage unit, anda transfer decision unit for, at the time of receiving a packet or a dummy packet from the receiving unit, determining whether or not to transfer the received packet or dummy packet, based on a packet length contained in the packet or the dummy packet, packet arrival history information stored in the packet arrival history storing unit, and a set bandwidth.

15. The packet forwarding apparatus according to claim 8, wherein the first and second transmission units further include a bandwidth control unit for controlling output of a packet, based on a received packet length for each class received from the receiving unit.

16. The packet forwarding apparatus according to claim 6, further comprising: a setting control unit for, upon receiving an input for setting a bandwidth, storing the bandwidth into the first and second transmission units, anda bandwidth control unit for controlling a packet transmitted at the second transmission unit and the packet length notified to the second transmission unit from the receiving unit, based on the bandwidth stored by the setting control unit.

17. The packet forwarding apparatus according to claim 8, wherein the first and second transmission units are respectively mounted on different printed circuit boards.

18. A bandwidth control method in a packet forwarding apparatus for transmitting a received packet from a plurality of ports, the bandwidth control method comprising the steps of: receiving a first packet;determining an output unit group for outputting the first packet;determining an output unit for outputting the first packet out of a plurality of output units corresponding to the determined output unit group;transferring the first packet to the determined output unit; andcontrolling, with a length of the first packet, transmission of a packet at an output unit other than the determined output unit out of a plurality of output units corresponding to the determined output unit group.