Transmitting and Receiving Side Terminals and Method of Monitoring Network Using the Same

1. A transmitting side terminal, comprising: a packet classifier configured to classify input service packets, used for a communication service to transmit data to a receiving side terminal over a network using a network bandwidth, as probing packets or non-probing packets, based on one or more respective features of the service packets, the probing packets being compatibly used for the communication service and probing to monitor the network without additionally consuming the network bandwidth; and a packet transmitter configured to selectively transmit the probing packets and the non-probing packets, wherein the packet classifier classifies a given input service packet of the input service packets as one of the probing packets when the given input service packet has a respective size greater than a predetermined probing size threshold, and classifies the given input service packet as a non-probing packet when the respective size is less than the predetermined probing size threshold.

2. The transmitting side terminal of claim 1 , wherein the packet transmitter transmits the classified probing packets in a packet train mode, in which a packet train comprising a group of probing packets having a predetermined time interval therebetween is transmitted, when a number of the probing packets is greater than a predetermined train threshold, and transmits the classified probing packets in a packet pair mode, in which a pair of probing packets are transmitted together, when the number of probing packets is less than the predetermined train threshold.

3. The transmitting side terminal of claim 2 , wherein, when a number of transmission of the packet train in the packet train mode exceeds a predetermined threshold, the packet transmitter transmits the probing packets in the packet pair mode.

4. The transmitting side terminal of claim 1 , further comprising a report message receiver configured to receive a report message pertaining to a network between the transmitting side terminal and a receiving side terminal receiving the probing packets from the receiving side terminal, wherein the message indicates one or more of an effective network capacity of the network, an achievable network throughput of the network, and an available network bandwidth of the network.

5. The transmitting side terminal of claim 4 , wherein, when the packet transmitter transmits the probing packets in the packet pair mode, the packet transmitter adjusts intervals between packet pairs based on a number of intervals between the packet pairs and the indicated available network bandwidth.

6. The transmitting side terminal of claim 4 , wherein, when the packet transmitter transmits the probing packets in a packet train mode, in which a packet train comprising a group of probing packets having a predetermined time interval therebetween is transmitted, the packet transmitter adjusts an interval between the packets in a packet train by calculating a time interval between packets based on the indicated effective network capacity.

7. The transmitting side terminal of claim 1 , wherein the packet transmitter inserts probing identification information in the probing packet headers and then transmits the probing packets.

8. A receiving side terminal, comprising: a packet receiver configured to receive service packets from a transmitting side terminal; a packet processor configured to: determine a given received service packet of the received service packets, used for a communication service to transmit data to a receiving side terminal over a network using a network bandwidth, as a received probing packet of a plurality of probing packets in response to detecting of probing identification information in a header of the given received service packet, the probing packets being compatibly used for the communication service and for probing to monitor the network without additionally consuming the network bandwidth, and extract and store respective headers of the probing packets; and a measurer configured to measure a network monitoring parameter using information included in the respective headers of the probing packets, wherein the transmitting side terminal inserts the probing identification information into the header of a given service packet when the given service packet has a respective size greater than a predetermined probing size threshold, and does not insert the probing identification information into the header of the given service packet when the respective size is less than the predetermined probing size threshold.

9. The receiving side terminal of claim 8 , wherein the measurer includes a measurement type determiner configured to store the respective headers of the probing packets in one of a first storage for storing headers of probing packets transmitted in a packet pair mode and a second storage for storing headers of probing packets transmitted in a packet train mode, according to transmission modes of the probing packets included in the probing identification information, wherein a pair of probing packets are transmitted together in the packet pair mode and a packet train comprising a group of probing packets having a predetermined time interval therebetween is transmitted in the packet train mode.

10. The receiving side terminal of claim 9 , wherein, when a number of packet pairs stored in the first storage exceeds a predetermined threshold pair number, the measurer calculates an effective network capacity using the stored packet pairs.

11. The receiving side terminal of claim 9 , wherein, when a respective sequence number of a packet corresponding to a header last stored in the second storage is equal to or greater than a last sequence number of the group constituting the packet train at a current point in time, the measurer calculates at least one of an achievable network throughput and an available network bandwidth using the group constituting the packet train.

12. The receiving side terminal of claim 9 , wherein: the measurer measures a reception interval between the probing packets, and generates a channel quality indicator (CQI) operation signal when the reception interval exceeds a predetermined threshold, and the measurer obtains a CQI of a wireless channel connected with the terminal using a CQI measurer when the CQI operation signal is generated.

13. A method of monitoring a network, comprising: classifying, at a transmitting side terminal, service packets, used for a communication service to transmit data to a receiving side terminal over a network using a network bandwidth, as probing packets or non-probing packets according to one or more respective features of the service packets, and transmitting the service packets, the probing packets being compatibly used for the communication service and for probing to monitor the network without additionally consuming a network bandwidth, determining, at a receiving side terminal, whether the service packets received from the transmitting side terminal are probing packets; and when the received service packets are probing packets, extracting headers of the probing packets, and measuring a network monitoring parameter using information included in the extracted headers of the probing packets, wherein the classifying of the service packets comprises: checking, at the transmitting side terminal, whether or not a respective size of a given service packet of the service packets exceeds a predetermined probing size threshold; when the respective size of the given service packet exceeds the predetermined probing size threshold, classifying the given service packet as one of the probing packets; and when the respective size of the given service packet does not exceed the predetermined threshold probing size, classifying the given service packet as one of the non-probing packets.

14. The method of claim 13 , wherein the transmitting of the probing packets comprises: checking whether a number of the probing packets exceeds a predetermined train threshold; and when the number of the probing packets does not exceed the predetermined train threshold, transmitting the probing packets in a packet pair mode, in which a pair of probing packets are transmitted together.

15. The method of claim 14 , wherein the transmitting of the probing packets further comprises, after the checking of whether the number of the probing packets exceeds the predetermined train threshold: when the number of the probing packets exceeds the predetermined train threshold, checking whether when a number of transmission of a packet train in a packet train mode exceeds a predetermined threshold, wherein a packet train comprising a group of probing packets having a predetermined time interval therebetween is transmitted in the packet train mode; and transmitting the probing packets in the packet pair mode when the number of transmission of the packet train exceeds the predetermined threshold, and transmitting the probing packets in the packet train mode, when the number of transmission of the packet train does not exceed the predetermined threshold.

16. The method of claim 13 , wherein the transmitting of the probing packets comprises inserting probing identification information, in the respective headers of the probing packets, and then transmitting the probing packets.

17. The method of claim 16 , wherein the measuring of the network monitoring parameter includes: storing, at the receiving side terminal, the respective headers of the probing packets in one of a first storage for storing headers of probing packets transmitted in a packet pair mode and a second storage for storing headers of probing packets transmitted in a packet train mode according to transmission modes of the probing packets included in the probing identification information; checking whether a number of the stored packet pairs exceeds a predetermined threshold pair number; and when the number of packet pairs exceeds the predetermined threshold pair number, calculating an effective network capacity using the stored packet pairs, wherein a pair of probing packets are transmitted together in the packet pair mode and a packet train comprising a group of probing packets having a predetermined time interval therebetween is transmitted in the packet train mode.

18. The method of claim 17 , further comprising, after the calculating of the effective network capacity: transmitting, from the receiving side terminal, an indication of the effective network capacity of the network, to the transmitting side terminal; and when the transmitting side terminal transmits the probing packets in the packet train mode, calculating a time interval between packets based on the indicated effective capacity and adjusting an interval between the packets in the packet train.

19. The method of claim 17 , wherein the measuring of the network monitoring parameter further comprises, after the storing of the headers of the probing packets in the one of the first storage and the second storage: checking, at the receiving side terminal, whether a sequence number of a packet corresponding to a header last stored in the second storage is equal to or greater than a last sequence number of the group constituting the packet train at a current point in time; and when the sequence number of the packet corresponding to the header last stored in the second storage is equal to or greater than the last sequence number of the group constituting the packet train at the current point in time, calculating at least one of an achievable network throughput and an available network bandwidth using the group constituting the packet train.

20. The method of claim 19 , further comprising, after the calculating of the at least one of the achievable network throughput and the available network bandwidth: transmitting, from the receiving side terminal, an indication of the available network bandwidth to the transmitting side terminal; and when the transmitting side terminal transmits the probing packets in the packet pair mode, adjusting intervals between the packet pairs according to a number of intervals between the packet pairs and the indicated available network bandwidth.

21. The method of claim 13 , further comprising, after the determining of whether the service packets received from the transmitting side terminal are probing packets: measuring, at the receiving side terminal, a reception interval between the probing packets; checking, at the receiving side terminal, whether the reception interval between the probing packets exceeds a predetermined threshold; and when the reception interval between the probing packets exceeds the predetermined threshold, obtaining a channel quality indicator (CQI) of a wireless channel connected with the receiving side terminal.