Packet shaping device, router, band control device and control method
A packet shaping device for the purpose of shaping a packet in which burst has grown in a router to an original packet without the burst growth is disclosed. The packet shaping device monitors an arrival time TA of each packet on which a pass time TP is recorded when the packet passes a prescribed pass point and calculates a delay time TD which is a time difference between the pass time TP and the arrival time TA. Then, the packet shaping device obtains a maximum delay time TD max among the delay times, and delays and sends all the arrived packets in such that the delay time of all the arrived packets is equivalent to the maximum delay time.
1. A packet shaping device for performing shaping to an original burst length when burst of flow consisted of packet strings has grown in a communication device, comprising:
arrival time monitoring means for monitoring an arrival time for each packet on which pass time has been recorded at a location of recording of said pass time;
pass time obtaining means for obtaining said pass time from the packet at a location of monitoring of the arrival time;
delay time calculation means for calculating delay times of arrived packets from the location of recording of said pass time to the location of monitoring of said arrival time, based on said pass time along with said arrival time;
maximum delay time obtaining means for obtaining, for each flow, a maximum delay time among the delay times of the packets that have arrived;
send time determining means for, based on the maximum delay time, determining send time of the arrived packets; and
packet sending means for sending said arrived packets at said send time, thereby performing packet shaping.
2. The packet shaping device according to claim 1 , wherein said packet sending means includes:
packet storing means for storing the arrived packets;
send time data output means for outputting said send time of the arrived packets; and
a packet output device for reading the arrived packets out of the packet storing means at said send time and outputting said arrived packets, thereby performing packet shaping.
3. The packet shaping device according to claim 1 , wherein said communication device comprises one or more groups of input lines and output lines, and said packet shaping device is provided in each output line.
4. The packet shaping device according to claim 1 , comprising means for clearing said maximum delay time if a packet does not arrive in a prescribed time.