Apparatus and method for processing packets

• US 20040264488A1
• Filed: 06/24/2004
• Published: 12/30/2004
• Est. Priority Date: 06/25/2003
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jeon, Seong-Joon, Youn, Myeon-Kee, Yoon, Hyun-Min
• Application Number:
  US10/874,341
• Publication Number:
  US 20040264488A1
• Time in Patent Office: Days
• US Class Current: 370/412
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/6462 Movable boundaries in packets or frames
• CPC Class Codes: H04L 2012/6481 Speech, voice
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/2416 Real-time traffic
• CPC Class Codes: H04L 47/2433 Allocation of priorities to traffic types
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 8/04 Registration at HLR or HSS [Home Subscriber Server]

Abstract

An apparatus and method for processing packets makes use of a double queue, manages medium access control(MAC) addresses of real-time service terminals through a link list, and assigns a priority to real-time service packets, so that when packet service is provided, the real-time service packets are processed in preference, and then when the real-time service packets are completely processed, data packets are processed. Thus, it is possible to guarantee the Quality of Service(QoS) of voice or moving image packets. In addition, when the real-time service packets are only the voice packets, a fragmentation threshold value is provided to the data terminals from which the data packets are transmitted, and when the data packets transmitted from the data terminals are processed, the maximum permissible delay time of the voice packets is calculated, and then each data packet is inserted between the voice packets. Thereby, it is possible to enhance throughput for traffic of each data terminal.

Claims

1. An apparatus for processing packets comprising:

a reception queue, including a first reception queue processing at least one real-time service packet and a second reception queue processing at least one data packet, for processing at least one of said real-time service and data packets received from at least one service terminal and for transmitting the processed packet to an Internet protocol network, said real-time service packet accommodating image and voice packet;

a transmission queue, including a first transmission queue processing at least one real-time service packet and a second transmission queue processing at least one data packet, for processing at least one of said real-time service and data packets received from said Internet protocol network and for transmitting the processed packet to the at least one service terminal; and

a packet processor for controlling transmission of said real-time service and data packets stored in said reception and transmission queues to any one of the Internet protocol network and the service terminal in accordance with a preset priority.

2. The apparatus of claim 1, wherein said service terminal includes at least one of:

at least one real-time service terminal for processing said real-time service packet to provide real-time voice and image services; and

at least one data terminal for processing the data packet to provide data communication service.

3. The apparatus of claim 1, further comprising:

a pre-processing controller for setting a priority to process at least one of transmitted/received packets according to kinds of the transmitted/received packets; and

a storage unit for storing information on the priority to compare and analyze kinds of the transmitted/received packets.

4. The apparatus of claim 3, wherein the priority information includes information on a medium access control address of said real-time service terminal.

5. The apparatus of claim 4, wherein the packet processor compares the medium access control addresses of the real-time service terminals stored in said storage unit with a source address of any one of transmitted and received packets to confirm whether to be matched with the source address, determines any one of the transmitted and received packets to be the real-time service packet when the matched medium access control address exists in said storage unit, and stores the result in any one of the first transmission and reception queues, and determines any one of the transmitted and received packets to be the data packet when the matched medium access control address does not exist in said storage unit and stores the result in any one of the second transmission and reception queues.

6. The apparatus of claim 5, wherein said packet processor includes:

a reception controller for preferentially processing the real-time service packet stored in said first reception queue, transmitting the processed packet to the Internet protocol network, and when the real-time service packets are all transmitted, transmitting the data packet stored in the second reception queue to the Internet protocol network; and

a transmission controller for preferentially processing the real-time service packet stored in said first transmission queue to transmit the packet to a real time service terminal, transmitting the processed packet to the Internet protocol network, and when the real-time service packets are all transmitted, transmitting the data packet stored in said second transmission queue to the service terminal.

7. The apparatus of claim 6, wherein said reception controller is holding transmission of the data packet when at least one new real-time service packet is coming in said first reception queue while the data packet stored in said second reception queue is processed and transmitted to the Internet protocol network, and after the new real-time service packets coming in said first reception queue are all transmitted to the Internet protocol network, transmitting the held data packet to the Internet protocol network.

8. The apparatus of claim 6, wherein said transmission controller is holding transmission of the data packet when at least one new real-time service packet is coming in said first transmission queue while the data packet stored in said second transmission queue is processed and transmitted to a data terminal of said service terminals, and after the new real-time service packets coming in said first transmission queue are all transmitted to the service terminals, transmitting the held data packet to a real-time service terminal of the service terminals.

9. The apparatus of claim 3, wherein when the real-time service packet is a voice packet, a fragmentation threshold value is calculated using an average permissible transmission delay time of the voice packet and the number of voice over Internet protocol and data terminals of the service terminals connected to a system and provides the result to the data terminal.

10. The apparatus of claim 6, wherein said packet processor:

controls the reception queue such that, when a voice packet is received from a voice over Internet protocol terminal of the service terminals, the received voice packet is preferentially processed and that the data packet transmitted from a data terminal of said service terminals is processed within an average permissible transmission delay time of the voice packet; and

processes the voice packet to be transmitted to the voice over Internet protocol terminal in preference and then the data packet to be transmitted to the data terminal within the average. permissible transmission delay time of the voice packet.

11. The apparatus of claim 9, wherein the average permissible transmission delay time of the voice packet in said pre-processing controller is calculated using at least one of:

the number of the voice over Internet protocol terminals connected to the system,

the number of the data terminals connected to the system,

a first time which it takes the voice over Internet protocol terminal to successfully complete transmission of one voice packet after acquisition of a channel,

a first lapse time consumed until the voice over Internet protocol terminal fails to transmit the voice packet,

a second time which it takes the data terminal to successfully complete transmission of one data packet after acquisition of a channel,

a second lapse time consumed until the data terminal fails to transmit the data packet,

a first probability of packet transmission by any one of the voice over Internet protocol terminal and the data terminal,

a second probability of packet transmission failure by any one of the voice over Internet protocol terminal and the data terminal,

a first average payload size of data packets,

a second average payload size of voice packets,

the maximum number of backoff stages, and

a data transmission rate of the system.

12. A method for processing packets comprising:

when any one of at least one real-time service packet and at least one data packet is received from an Internet protocol network, storing the received packets in different transmission queues respectively based on kinds of the received packets, the real-time service packet accommodating image and voice packet; and

processing the real-time service packets stored in said transmission queues in preference, transmitting the processed real-time service packets to at least one real-time service terminal, processing the data packets stored in said transmission queues after transmission of the real-time service packets is completed, and transmitting the processed data packets to at least one data terminal.

13. The method of claim 12, wherein the step of storing the received packets in different transmission queues includes comparing previously stored medium access control addresses of said real-time service terminals with a source address of a packet received from the Internet protocol network to confirm whether to be matched with the source address, determining the received packet to be the real-time service packet when the matched medium access control address is present, and storing the result in a real-time service packet transmission queue of said transmission queues, determining the received packet to be the data packet when the matched medium access control address is not present, and storing the result in a data transmission queue of said transmission queues.

14. The method of claim 12, wherein the step of processing the real-time service packets and transmitting the real-time service and data packets stored in said transmission queues includes holding transmission of the data packet when at least one new real-time service packet is coming in a real-time service packet transmission queue of said transmission queues while the data packet stored in a data transmission queue of said transmission queues is processed and transmitted to said data terminal, and after the new real-time service packets coming in said real-time service packet transmission queue are all transmitted to said real-time service terminal, transmitting the held data packet to said data terminal.

15. The method of claim 12, further comprising:

when any one of the real-time service packet and the data packet is received from any one of said real-time service terminal and the data terminal, storing the received packets in different reception queues respectively based on kinds of the received packets, the real-time service packet accommodating image and voice packet; and

processing the real-time service packets stored in said reception queues in preference, transmitting the processed real-time service packets to the Internet protocol network, processing the data packets stored in said reception queues after transmission of the real-time service packets is completed, and transmitting the processed data packets to the Internet protocol network.

16. The method of claim 15, wherein the step of storing the received packets in different reception queues respectively based on kinds of the received packets includes comparing previously stored medium access control addresses of said real-time service terminals with a source address of a packet received from any one of said real-time service terminal and said data terminal to confirm whether to be matched with the source address, determining the received packet to be the real-time service packet when the matched medium access control address is present, and storing the result in a real-time service packet reception queue of the reception queues, determining the received packet to be the data packet when the matched medium access control address is not present, and storing the result in a data reception queue of the reception queues.

17. The method of claim 15, wherein said step of processing the real-time service and data packets stored in said reception queues, and transmitting the processed real-time service packets and data packets to the Internet protocol network, includes holding transmission of the data packet when at least one new real-time service packet is coming in a real-time service packet reception queue of the reception queues while the data packet stored in a data reception queue of the reception queues is processed and transmitted to the Internet protocol network, and after the new real-time service packets coming in the real-time service packet reception queue are all transmitted to the Internet protocol network, transmitting the held data packet to the Internet protocol network.

18. An apparatus for processing packets comprising:

a reception queue for sequentially storing any one of at least one real-time service packet and at least one data packet which are received from at least one service terminal;

a transmission queue for storing at least one real-time service packet and at least one data packet which are received from an Internet protocol network in different queues respectively; and

a transmission/reception controller for controlling transmission of the real-time service and data packets stored in said transmission queue to the Internet protocol network in accordance with a preset priority and transmission of the packets stored in said reception queue through a sequential processing operation.

19. The apparatus of claim 18, further comprising:

a pre-processing controller for setting a priority to process the packets according to kinds of the packets received from the Internet protocol network; and

a storage unit for storing information on the priority to compare and analyze the kinds of packets received from the Internet protocol network.

20. The apparatus of claim 19, wherein the priority information includes information on a medium access control address of the real-time service terminal.

21. The apparatus of claim 18, wherein the transmission/reception controller compares the medium access control addresses of the real-time service terminals stored in said storage unit with a source address of at least one packet received from the Internet protocol network to confirm whether to be matched with the source address, determines the received packet to be the real-time service packet when the matched medium access control address exists in said storage unit, and stores the result in a real-time service packet transmission queue of said transmission queue, and determines the received packet to be the data packet when the matched medium access control address does not exist in the storage unit and stores the result in a data transmission queue of said transmission queue.

22. The apparatus of claim 18, wherein the transmission/reception controller includes:

a transmission controller for sequentially processing any one of the real-time service and data packets stored in said reception queue according to a first in first out discipline and for transmitting the processed result to the Internet protocol network; and

a reception controller for preferentially processing the real-time service packet stored in a real-time service packet transmission queue of said transmission queue, transmitting the processed result to a real-time service terminal of the service terminals, and when the real-time service packets are all transmitted, transmitting the data packet stored in a data transmission queue of the transmission queue to a data terminal of the service terminal.

23. The apparatus of claim 22, wherein said transmission controller is holding transmission of the data packet when at least one new real-time service packet is coming in said real-time service packet transmission queue while the data packet stored in the data transmission queue is processed and transmitted to the data terminal, and after the new real-time service packets coming in the real-time service packet transmission queue are all transmitted to the real-time service terminal, transmitting the held data packet to the data terminal.

24. A method for processing packets comprising:

when any one of at least one real-time service packet and at least one data packet is received from an Internet protocol network, storing the received packets in a real-time service packet transmission queue and a data transmission queue respectively based on the kinds of received packets, and sequentially storing any one of at least one real-time service packet and at least one data packet which are received from at least one service terminal in a reception queue, real-time service packet accommodating image and voice packet; and

processing the real-time service packets stored in said real-time service packet transmission queue in preference, transmitting the processed real-time service packets to at least one real-time service terminal, processing the data packets stored in said data transmission queue after transmission of the real-time service packets is completed, and transmitting the processed data packets to at least one data terminal,

sequentially transmitting at least one of the real-time service packets and the data packets which are sequentially stored in said reception queue to the Internet protocol network.

25. The method of claim 24, wherein the step of storing the received packets in said real-time service packet transmission queue and said data transmission queue and sequentially storing any one of at least one real-time service packet and at least one data packet in a reception queue, includes comparing previously stored medium access control addresses of said real-time service terminals with a source address of a packet received from the Internet protocol network to confirm whether to be matched with the source address, determining the received packet to be the real-time service packet when the matched medium access control address is present, and storing the received packet in said real-time service packet transmission queue, determining the received packet to be the data packet when the matched medium access control address is not present, and storing the received packet in said data transmission queue.

26. The method of claim 24, wherein the step of processing the real-time service packets stored in said real-time service packet transmission queue in preference, transmitting the processed real-time service packets to at least one real-time service terminal, processing the data packets stored in said data transmission queue after transmission of the real-time service packets is completed, and transmitting the processed data packets to at least one data terminal, includes holding transmission of the data packet when at least one new real-time service packet is coming in said real-time service packet transmission queue while the data packet stored in said data transmission queue is processed and transmitted to said data terminal, and after the new real-time service packets coming in the real-time service packet transmission queue are all transmitted to the real-time service terminal, transmitting the held data packet to said data terminal.

27. An apparatus for processing packets, comprising:

a pre-processing controller for calculating a fragmentation threshold value and for providing the calculated fragmentation threshold value to at least one service terminal;

a reception queue, including a voice reception queue processing at least one voice packet and a data reception queue processing at least one data packet, for processing at least one packet received from said service terminal and for transmitting the processed packet to an Internet protocol network;

a transmission queue, including a voice transmission queue processing at least one voice packet and a data transmission queue processing at least one data packet, for processing at least one packet received from the Internet protocol network and for transmitting the processed packet to said service terminal; and

a transmission/reception controller for controlling transmission of the real-time service and data packets stored in the reception and transmission queues to any one of the Internet protocol network and the service terminal in accordance with a preset priority.

28. The apparatus of claim 27, wherein said service terminal includes at least one of:

at least one voice over Internet protocol terminal for processing the voice packet to provide voice service; and

at least one data terminal for processing the data packet to provide data communication service.

29. The apparatus of claim 27, wherein the transmission/reception controller includes:

a reception controller for controlling the reception queue so that the voice packet transmitted from a voice over Internet protocol terminal of said service terminals is preferentially processed and that the data packet transmitted from a data terminal of the service terminals within an average permissible transmission delay time of the voice packet; and

a transmission controller for controlling the transmission queue accommodating the voice packet to be transmitted to the voice over Internet protocol terminal is preferentially processed and the data packet to be transmitted to the data terminal is within the average permissible transmission delay time of the voice packet.

30. The apparatus of claim 27, wherein the pre-processing controller calculates the fragmentation threshold value using the average permissible transmission delay time of the voice packet and the number of voice over Internet protocol and data terminals of the service terminals when the number of the voice over Internet protocol terminals is changed.

31. The apparatus of claim 30, wherein the average permissible transmission delay time of the voice packet is calculated using at least one of:

the number of the voice over Internet protocol terminals connected to the system,

the number of the data terminals connected to the system,

a first time which it takes the voice over Internet protocol terminal to successfully complete transmission of one voice packet after acquisition of a channel,

a first lapse time consumed until the voice over Internet protocol terminal fails to transmit the voice packet,

a second time which it takes the data terminal to successfully complete transmission of one data packet after acquisition of a channel,

a second lapse time consumed until the data terminal fails to transmit the data packet,

a first probability of packet transmission by any one of the voice over Internet protocol terminal and the data terminal,

a second probability of packet transmission failure by any one of the voice over Internet protocol terminal and the data terminal,

a first average payload size of data packets,

a second average payload size of voice packets,

the maximum number of backoff stages, and

a data transmission rate of the system.

32. A method for processing packets comprising:

when the number of voice over Internet protocol terminals is changed, calculating a fragmentation threshold value and transmitting the calculated fragmentation threshold value to at least one data terminal connected to a system;

when any one of at least one voice packet and at least one data packet is received from any one of said voice over Internet protocol terminal and said data terminal, storing the received packet in a corresponding queue according to a kind of the received packet; and

processing the voice packet stored in the queue in preference, transmitting the processed voice packet to the Internet protocol network, processing the data packet within an average permissible transmission delay time (X), and transmitting the processed data packet to the Internet protocol network.

33. The method of claim 32, wherein the step of storing the received packet in said corresponding queue according to a kind of the received packet, includes storing the voice packet in a voice reception queue of the queue when the received packet is the voice packet, and storing the data packet in a data reception queue of the queue when the received packet is the data packet.

34. The method of claim 32, wherein the step of calculating the fragmentation threshold value and transmitting the calculated fragmentation threshold value to at least one data terminal connected to said system, includes:

detecting whether the number of the voice over Internet protocol terminals connected to the system is changed or not;

calculating the average permissible transmission delay time (X) when the number of the voice over Internet protocol terminals is changed; and

calculating the fragmentation threshold value using the calculated average permissible transmission delay time and the number of voice over Internet protocol and data terminals connected to the system and transmitting the calculated fragmentation threshold value to the data terminal.

35. The method of claim 34, wherein the average permissible transmission delay time of the voice packet is calculated using at least one of:

the number of the voice over Internet protocol terminals connected to the system,

the number of the data terminals connected to the system,

a first time which it takes the voice over Internet protocol terminal to successfully complete transmission of one voice packet after acquisition of a channel,

a first lapse time consumed until the voice over Internet protocol terminal fails to transmit the voice packet,

a second time which it takes the data terminal to successfully complete transmission of one data packet after acquisition of a channel,

a second lapse time consumed until the data terminal fails to transmit the data packet,

a first probability of packet transmission by any one of the voice over Internet protocol terminal and the data terminal,

a second probability of packet transmission failure by any one of the voice over Internet protocol terminal and the data terminal,

a first an average payload size of data packets,

a second average payload size of voice packets,

the maximum number of backoff stages, and

a data transmission rate of the system.

36. The method of claim 32, wherein the step of processing the voice packet stored in the queue in preference, transmitting the processed voice packet to the Internet protocol network, processing the data packet within an average permissible transmission delay time (X), and transmitting the processed data packet to the Internet protocol network, further comprises:

checking whether the voice packet exists in a corresponding reception queue within the average permissible transmission delay time; and

as a result of the checking, when the voice packet exists in the corresponding reception queue within the average permissible transmission delay time, processing the data packet and transmitting the processed data packet to the Internet protocol network.

37. The method of claim 32, further comprising:

when the data packets or the voice packets are received from the Internet protocol network, storing the received packets in different transmission queues respectively based on the kinds of received packets; and

processing the voice packets stored in said transmission queues in preference, transmitting the processed voice packets to said voice over Internet protocol terminals, processing the data packets within the average permissible transmission delay time, and transmitting the processed data packets to said data terminals.

38. The method of claim 37, wherein the step of processing the voice packets stored in said transmission queues in preference, transmitting the processed voice packets to said voice over Internet protocol terminals, processing the data packets within the average permissible transmission delay time, and transmitting the processed data packets to said data terminals, further comprises:

checking whether the voice packet to be processed within the average permissible transmission delay time exists in said transmission queue; and

as a result of the checking, when the voice packet to be processed within the average permissible transmission delay time does not exist, processing the data packets and transmitting the processed data packets to said data terminals.

39. The method of claim 32, wherein the average permissible transmission delay time (X) of the voice packet is determined by the following:

X=T_srcnode+T_uplink+T_AP+T_downlink+T_dstnode≦

150 milliseconds,

where T_srcnode represents a packet transmission delay time at the service terminals intended to transmit the packets, T_uplink represents a packet transmission delay time between the service terminals of the voice over Internet protocol terminal and data terminal, intended to transmit the packets and the system, T_AP represents a packet transmission delay time at the system, T_downlink represents a packet transmission delay time between the service terminals of the voice over Internet protocol terminal and data terminal, intended to receive the packets and the system, T_dstnode represents a transmission delay time at the service terminals receiving the packets.

40. The method of claim 39, wherein the T_srcnode is determined by the following:

T_srcnode=(coding)+(packetization)+(buffering)+(I/O processing),

where T_srcnode has a fixed value allocated according to the kinds of coding patterns, and the time values of the packetization, buffering, and the input and output processing are previously given by vendors.

41. The method of claim 39, wherein the T_uplink is determined by the following:

T_uplink=((N_V*T_Vcoll*P)+(N_V*T_Vsucc*(1−

P)))+((N_V*T_Dcoll*P)+(N_V*T_Dsucc*(1−

P))),

where N_V is the number of the voice over Internet protocol terminals connected to the system, N_D is the number of the data terminals connected to the apparatus, T_Vcoll is a time consumed until the voice over Internet protocol terminal fails to transmit the voice packet, T_Vsucc represents a time which it takes the voice over Internet protocol terminal to completely transmit one voice packet after acquisition of a channel, T_Dcoll is a time consumed until the data terminal fails to transmit the data packet, T_Dsucc is a time which it takes the data terminal to completely to transmit the data packet after acquisition of a channel, and P is the probability of packet transmission failure or collision of any one of the voice over Internet protocol terminal and the data terminal.

42. The method of claim 41, wherein the T_uplink, the transmission delay time between the voice over Internet protocol and data terminals and the system, at a certain time being identical to the maximum standby time T_vi lapsing, by one voice over Internet protocol terminal, from after transmitting a current packet to before transmitting the next packet, where the T_vi is a time of waiting for to transmit the next packet after all service terminals connected to the system each transmit packets at least once when one voice over Internet protocol terminal is about to transmit a new one next to a current packet in a distributed coordination function (DCF) mode.

43. The method of claim 39, wherein the T_AP is determined by the following:

T_AP=(I/O processing)+(queuing)+(packet processing)

where T_AP is a fixed value because the time values of the input and output processing, queuing and packet processing are previously given by vendors.

44. The method of claim 41, wherein the T_Vcoll is determined by the following:

Basic mode;

T_Vcoll=(E[VoIP]/λ

)+DIFS,RTS/CTS mode;

T_Vcoll=RTS+DIFS,

where E[VoIP] is an average payload size of voice packets, DIFS stands for distributed coordination function integer frame space and is the longest time interval between delay packets/frames, RTS stands for ready to send is a time lapsing for transferring a signal indicating that the system is prepared to receive data, λ

is the transmission rate of the system, and the CTS represents clear to send and is a time for transferring a signal informing all of peripheral terminals connected to a corresponding system that the service terminals of the voice over Internet protocol terminal and data terminal, are prepared to receive data.

45. The method of claim 41, wherein the T_Vsucc is determined by the following:

Basic mode;

T_Vsucc=(E[VoIP]/λ

)+SIFS+ACK+DIFS,RTS/CTS mode;

T_Vsucc=RTS+3SIFS+CTS+(E[VoIP]/λ

)+ACK+DIFS,

where CTS represents clear to send and is a time for transferring a signal informing all of peripheral terminals connected to a corresponding system that the service terminals of the voice over Internet protocol terminal and data terminal, are prepared to receive data, and the ACK represents acknowledgement and is a time for transferring an ACK packet informing a normal reception of a packet, and SIFS represents short inter frame space, is a short standby time used for the ACK, the CTS, and a polling operation, and is capable of spending the ACK or the CTS by a terminal prior to a terminal that should wait for the DIFS with the highest priority.

46. The method of claim 41, wherein the T_Dcoll is determined as follows:

Basic mode;

T_Dcoll=(E[D]/λ

)+DIFS,RTS/CTS mode;

T_Dcoll=RTS+DIFS,

where E[D] is an average payload size of data packets, DIFS represents distributed coordination function integer frame space and is the longest time interval between delay packets/frames, RTS represents ready to send and is a time lapsing for transferring a signal indicating that the system is prepared to receive data, λ

is the transmission rate of the system, CTS represents clear to send and is a time for transferring a signal informing all of peripheral terminals connected to a corresponding system that the service terminals of the voice over Internet protocol terminal and data terminal, are prepared to receive data.

47. The method of claim 41, wherein the T_Dsucc is determined as follows:

Basic mode;

T_Dsucc=(E([D]/λ

)+SIFS+ACK+DIFS,RTS/CTS mode;

T_Dsucc=RTS+3DIFS+CTS+(E[D]/λ

)+ACK+DIFS,

where E[D] is an average payload size of data packets, DIFS represents the distributed coordination function integer frame space and is the longest time interval between delay packets/frames, RTS represents ready to send and is a time lapsing for transferring a signal indicating that the system is prepared to receive data, λ

is the transmission rate of the system, CTS represents clear to send and is a time for transferring a signal informing all of peripheral terminals connected to a corresponding system that the service terminals of the voice over Internet protocol terminal and data terminal, are prepared to receive data, SIFS represents short inter frame space and is a short standby time used for the ACK, the CTS, and a polling operation, and ACK is a time for transferring an ACK packet informing a normal reception of a packet.

48. The method of claim 41, wherein the P is determined as follows:

P=1−

(1−

τ

)^n-1,

where the parameter τ

represents the probability of performing packet transmission by the voice over Internet protocol terminal or the data terminal in a randomly given slot time, the value of n is the number of packet transmission trials.

49. The method of claim 48, with the probability τ

is calculated by the following;

50. A computer-readable medium having computer-executable instructions for performing a method, comprising:

when any one of at least one real-time service packet and at least one data packet is received from an Internet protocol network, storing the received packets in different transmission queues respectively based on kinds of the received packets, the real-time service packet accommodating image and voice packet; and

processing the real-time service packets stored in said transmission queues in preference, transmitting the processed real-time service packets to at least one real-time service terminal, processing the data packets stored in said transmission queues after transmission of the real-time service packets is completed, and transmitting the processed data packets to at least one data terminal.

51. A computer-readable medium having stored thereon a data structure comprising:

a first field containing data representing, when the number of voice over Internet protocol terminals is changed, calculating a fragmentation threshold value and transmitting the calculated fragmentation threshold value to at least one data terminal connected to a system;

a second field containing data representing, when any one of at least one voice packet and at least one data packet is received from any one of said voice over Internet protocol terminal and said data terminal, storing the received packet in a corresponding queue according to a kind of the received packet; and

a third field containing data representing processing the voice packet stored in the queue in preference, transmitting the processed voice packet to the Internet protocol network, processing the data packet within an average permissible transmission delay time, and transmitting the processed data packet to the Internet protocol network.