JP2004312501A - Packet receiving method and packet receiver - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a packet receiving method and a packet receiver capable of suppressing the disturbance in the reproduced audio and video without requiring an additional protocol in a transmission terminal, even if a bit error occurs in the head packet of the fragments or a long packet larger than a packet length defined by a protocol is received, in a packet communication network in which bit errors in packets are unavoidable. <P>SOLUTION: This receiver is provided with an inspection bit check means 410, a detected bit error notifying means 411, a packet transmitting means 412, a video/audio data check means 413 for determining whether or not the video/audio data check means has transmitted video audio data to a received packet having a bit error. Since the video/audio data can be taken out from the received packet in this way, only a receiving terminal can suppress the disturbance of the reproduced video and audio. Accordingly, when a bit error occurs in a UDP packet for transmitting video/audio data, the packet is usually discarded, and the problem that the reproduced video/audio has a large disturbance can be solved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to data reception using a packet communication network. In particular, the present invention relates to a packet-type terminal that receives and reproduces video and audio data in real time using UDP (User Datagram Protocol) via a communication network in which bit errors in the packet cannot be avoided. The present invention relates to a receiving method and a receiving apparatus capable of suppressing disturbance of reproduced video and audio undesired for a viewer even when it occurs, and particularly to a MAC layer protocol.
[0002]
[Prior art]
Conventionally, when a packet loss of a UDP packet or a bit error of a packet occurs, a method of requesting a retransmission from a reception side to a transmission terminal, and the transmission terminal retransmitting the data of the loss portion to compensate for the lost data is known. (For example, see Patent Document 1).
[0003]
[Patent Document 1]
JP 2001-136195 A
[Problems to be solved by the invention]
However, in the conventional method for compensating for UDP packets, a retransmission mechanism is added to a UDP that does not have a retransmission mechanism. Therefore, although there is an advantage that it can be completely compensated except for the problem related to retransmission delay, lost data is retransmitted. Therefore, there is a problem that complicated control is required, and it cannot be realized only by the receiving terminal, and the transmitting terminal also needs a retransmission mechanism.
[0005]
Further, in a packet communication network, communication protocols are hierarchized, and an OSI (Open System Interconnection) reference model defined by ISO (International Organization for Standardization) is often used for describing the protocol. Here, the features of UDP / IP / Ethernet (R) will be described in comparison with the OSI reference model.
[0006]
UDP is a protocol located at the transport layer (fourth layer) in the OSI reference model, and is unreliable communication without a retransmission mechanism for packet loss and packet bit errors. Since the protocol processing can be executed at a higher speed than a TCP (transmission control protocol) having a retransmission mechanism by a protocol, the use thereof has been widespread in streaming distribution in which video and audio data are simultaneously reproduced while being received.
[0007]
IP is a protocol located at the network layer (third layer) in the OSI reference model, and has a role of transmitting data from a transmitting terminal to a receiving terminal beyond a node (packet relay device), but there is no compensation that can be reliably reached. A protocol that provides unreliable communication.
[0008]
The Ethernet (R) protocol is a protocol located in the data link layer (second layer) in the OSI reference model. A protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address is called a MAC (media access control) protocol, and Ethernet (R) is one of the MAC layer protocols. In addition, there are a MAC layer protocol for wireless communication and a MAC layer protocol for ATM (asynchronous transfer mode). Note that the physical address is also called a MAC address. Ethernet (R) also defines the electrical characteristics and connectors of the communication medium classified as the physical layer of the OSI reference model, but does not relate to the present invention, and a description thereof will be omitted.
[0009]
Each layer packet is composed of a header for storing control information and a payload for storing data to be transmitted. A UDP packet is composed of a UDP header and a UDP payload. The IP layer is one layer below the UDP layer, and is composed of an IP header and an IP payload. The payload stores a UDP packet. Ethernet (R) is one layer below the IP layer, and is composed of an Ethernet (R) header and an Ethernet (R) payload, and an IP packet is stored in the payload.
[0010]
Here, the protocol of each layer specifies the maximum packet size, and if the packet size of the upper layer exceeds the maximum packet size of the lower layer during transmission, it is divided into multiple packets so that it fits in the maximum packet size of the lower layer. Is done. This division is called a fragment, and the divided packet is called a fragment packet.
[0011]
The maximum packet size for UDP and IP is 65535 octets, and the maximum payload size for Ethernet® is 1500 octets. Therefore, when the packet size of the IP packet storing the UDP packet in the payload exceeds 1500 octets, the UDP packet is divided into a plurality of pieces to generate a plurality of IP packets of 1500 octets or less. Here, the first fragment packet has a UDP header, but the second and subsequent fragment packets do not have a UDP header. The transmitting / receiving terminal identifies the communication channel of the packet using the IP address and the port number of the UDP header. The second and subsequent fragmented packets do not have a UDP header, but non-fragmented packets have different IP header IDs for each IP packet, whereas fragmented packets have the same IP header ID within the same fragmented packet. , The UDP header can be known from the first packet of the same fragment by using the ID, so that the communication channel of the second and subsequent fragment packets can be identified.
[0012]
According to such a UDP / IP protocol specification, when a bit error or loss occurs in the first packet of a fragment, the communication channel of the packet cannot be identified because the UDP header of the same fragment packet cannot be known, and the fragment 2 The subsequent packets are discarded.
[0013]
On the other hand, when transmitting video and audio data by UDP, the size of the video and audio data is generally larger than the maximum payload size of Ethernet (R), and thus, fragments often occur. Therefore, when the first packet of the fragment is discarded by the MAC layer protocol because a bit error occurs or the packet exceeds a predetermined packet size, not only the first packet but also the second and subsequent fragment packets are included. There is a problem that a large amount of data is discarded, and a large disturbance occurs in reproduction of video and audio.
[0014]
The present invention solves such a problem, and in a packet communication network in which a bit error of a packet cannot be avoided, an additional protocol is not required for a transmitting terminal, and when a bit error occurs in a leading packet of a fragment, It is another object of the present invention to provide a packet receiving method and a packet receiving apparatus that can suppress disturbance of video / audio reproduction even when a long packet exceeding a predetermined packet length of a protocol is received.
[0015]
[Means for Solving the Problems]
In order to solve the above problem, a packet receiving method according to the present invention (claim 1) has a video / audio data determining step, and even when a check bit error occurs, a packet is discarded without discarding the packet. It is transmitted to the upper protocol execution step. With this configuration, if the packet in which the bit error has occurred is transmitting video and audio data, the video and audio data can be transmitted to the upper protocol execution step.
[0016]
The packet receiving method according to the present invention (claim 2) includes a long packet determining step and a packet transmitting step of transmitting a packet to an upper layer when a long packet is detected. The packet is transmitted to the upper protocol execution step without being discarded. With this configuration, if the long packet is transmitting video and audio data, the video and audio data can be transmitted to the upper protocol execution step.
[0017]
The packet receiving method according to the present invention (claim 3) has an upper header extracting step of extracting a header of a protocol of a higher layer than the MAC layer, and transmits the header of the protocol of the upper layer to an upper protocol execution step. With this configuration, even when a bit error occurs in the first packet of the fragment packet, the attributes of the second and subsequent packets of the same fragment packet can be determined by extracting the upper header of the first packet. The second and subsequent packets can be used without being discarded.
[0018]
The packet receiving apparatus according to the present invention (claim 4) has a video / audio data determining unit, and transmits a packet to a higher-level protocol executing unit without discarding the packet even when a check bit error occurs. With this configuration, if the check bit error packet is transmitting video and audio data, the video and audio data can be transmitted to the higher-level protocol execution unit.
[0019]
The packet receiving apparatus according to the present invention (claim 5) has a long packet determining means and a packet transmitting means for transmitting a packet to an upper layer when a long packet is detected. The packet is transmitted to the upper protocol execution step without discarding the packet. With this configuration, if the long packet is transmitting video and audio data, the video and audio data can be transmitted to the upper protocol execution step.
[0020]
The packet receiving apparatus according to the present invention (claim 6) has an upper-layer protocol extracting unit that extracts a header of a protocol of an upper layer than the MAC layer, and transmits the header of the upper-layer protocol to an upper-layer protocol executing unit. . With this configuration, even when a bit error occurs in the first packet of the fragment packet, the attributes of the second and subsequent packets of the same fragment packet can be determined by extracting the upper header of the first packet. The second and subsequent packets can be used without being discarded.
[0021]
With this configuration, the method and apparatus described above can be realized only by the receiving terminal without requiring a special additional protocol at the transmitting terminal.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0023]
FIG. 4 is a diagram illustrating an overall image of the packet receiving method according to the first, second, or third embodiment of the present invention.
[0024]
In FIG. 4, a MAC layer protocol execution step 100 is a step of executing a protocol in a MAC layer of a received packet, an upper protocol execution step 200 is a step of executing a protocol of an upper layer than the MAC layer, and a network layer protocol execution step 210 is The step of executing the network layer protocol in the upper protocol execution step 200, and the step of executing the transport layer protocol 220 are the steps of executing the transport layer protocol in the upper protocol execution step 200.
[0025]
FIG. 8 is a diagram illustrating an overall image of the packet receiving device according to the fourth, fifth, or sixth embodiment of the present invention.
[0026]
In FIG. 8, a MAC layer protocol executing means 400 executes a protocol in a MAC layer of a received packet, an upper protocol executing means 500 executes a protocol in an upper layer than the MAC layer, and a network layer protocol executing means 510 includes: The means for executing the network layer protocol in the upper protocol execution step 500 and the transport layer protocol execution means 520 are means for executing the transport layer protocol in the upper protocol execution means 500.
[0027]
(Embodiment 1)
FIG. 1 is a diagram illustrating a packet receiving method according to a second embodiment of the present invention (claim 1).
[0028]
In FIG. 1, a packet reception determination step 110 is a step of determining whether a packet has been received, a check bit determination step 111 is a step of determining whether the check bits of a received packet are normal, and a check bit error notification step 112 is The step of notifying the upper protocol execution step 200 of the occurrence of the check bit error, the step of determining audio / video data 113 checks the headers of the MAC layer, the IP layer and the UDP layer, and determines whether the received packet transmits the audio / video data. The packet transmission step 114 is a step of transmitting a received packet to the upper protocol execution step 200, and the termination determination step 115 is a step of determining whether or not to end the operation.
[0029]
In the video / audio data determination step 113, the source IP address of the IP header matches the IP address of the video / audio data transmitting station, the destination IP address of the IP header matches the IP address of its own station, and The upper protocol field indicates UDP, the source port number in the UDP header matches the port number used by the video / audio data transmitting station to transmit video / audio data, and the destination port number in the UDP header is the local station. If the received packet matches the port number for receiving the video / audio data, it is determined that the received packet is a video / audio packet.
[0030]
Also, in the case of Ethernet (R), the total size of the Ethernet (R) header, the IP header, and the UDP header is 42 octets when there is no IP header option, and therefore, the ratio of the header to the maximum packet size of 1500 octets. Is only 2.8%. The video and audio data is considered to be sufficiently large with respect to 1500 octets, and the payload size of the Ethernet (R) packet transmitting the video and audio data is considered to be a large value closer to 1500 octets. Therefore, the probability that an abnormality has occurred in the video and audio data is much higher than the probability that an abnormality has occurred in the header including the upper layer protocol when a check bit error has occurred. In addition, the error occurrence portion does not extend to all data of the payload, but may occur for some data. Therefore, when the video and audio data is processed without regarding to discarding the packet and assuming that the header is normal, the disturbance in the reproduced video and audio is reduced.
[0031]
According to this configuration, when the check bit error packet is received, the MAC layer also checks the headers of the IP layer and the UDP layer to determine whether or not the data being transmitted is video / audio data. In the case of a voice packet, the packet can be transmitted to an upper protocol execution step without discarding the packet.
[0032]
(Embodiment 2)
FIG. 2 illustrates a packet receiving method according to the second embodiment of the present invention (claim 2).
[0033]
2, the same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and description thereof is omitted. The long packet determination step 116 is a step for determining whether or not the received packet is a long packet. The long packet notification step 117 is a step for notifying the upper protocol execution step 200 that the long packet has been received.
[0034]
According to this configuration, when the long packet is received, the MAC layer also checks the headers of the IP layer and the UDP layer to determine whether the data being transmitted is video / audio data. In this case, the packet can be transmitted to the upper protocol execution step without discarding the packet.
[0035]
(Embodiment 3)
FIG. 3 is a diagram for explaining a packet receiving method according to the third embodiment of the present invention (claim 3).
[0036]
The same components as those in FIGS. 1 and 4 are denoted by the same reference numerals, and description thereof is omitted. The upper header extraction step 118 extracts a header higher than Ethernet (R), the upper header transmission step 119 transmits the extracted upper header to the upper protocol execution step, and the packet discard step 120 discards the packet. It is.
[0037]
According to such a configuration, not only the check bit error packet is simply discarded, but also the upper header is extracted and transmitted to the upper protocol execution step 200. Therefore, even if a bit error occurs in the first packet of the fragment, The upper protocol execution step 200 can determine the attributes of the second and subsequent packets.
[0038]
When a check bit error occurs, the upper header is extracted and the upper header is transmitted to the upper protocol execution step. However, regardless of whether a check bit error occurs, the upper header is always extracted and transmitted. May be.
[0039]
(Embodiment 4)
FIG. 5 is a diagram for explaining a packet receiving method according to the fourth embodiment of the present invention (claim 4).
[0040]
In FIG. 5, check bit determination means 410 determines whether the check bit of the received packet is normal, check bit error notification means 411 notifies upper protocol execution means 500 that a check bit error has occurred, The video / audio data determining means 413 examines the header of the transport layer from the MAC layer, and determines whether or not the received packet transmits the video / audio data. The packet transmitting means 412 transmits the received packet to the upper-layer protocol executing means 500. Means for transmitting the
[0041]
The video / audio data determination means 413 determines that the source IP address of the IP header matches the IP address of the video / audio data transmitting station, the destination IP address of the IP header matches the IP address of the own station, and The upper protocol field indicates UDP, the source port number in the UDP header matches the port number used by the video / audio data transmitting station to transmit video / audio data, and the destination port number in the UDP header is the local station. If the received packet matches the port number for receiving the video / audio data, it is determined that the received packet is a video / audio packet.
[0042]
According to this configuration, when the check bit error packet is received, the MAC layer also checks the headers of the IP layer and the UDP layer to determine whether or not the data being transmitted is video / audio data. In the case of a voice packet, a device for transmitting the packet to the upper protocol execution step without discarding the packet can be realized.
[0043]
(Embodiment 5)
FIG. 6 is a diagram for explaining a packet receiving method according to the fifth embodiment of the present invention (claim 5).
[0044]
The same components as those in FIGS. 5 and 8 are denoted by the same reference numerals, and description thereof is omitted. The long packet determining unit 414 is a unit that determines whether the received packet is a long packet, and the long packet notifying unit 415 is a unit that notifies the upper protocol executing unit 500 that the long packet has been received.
[0045]
According to this configuration, when the long packet is received, the MAC layer also checks the headers of the IP layer and the UDP layer to determine whether the data being transmitted is video / audio data. In this case, the packet can be transmitted to the upper protocol execution step without discarding the packet.
[0046]
(Embodiment 6)
FIG. 7 illustrates a packet receiving method according to the sixth embodiment of the present invention (claim 6).
[0047]
The same components as those in FIGS. 5 and 8 are denoted by the same reference numerals, and description thereof is omitted. The upper header extracting unit 416 is a unit for extracting a header higher than Ethernet (R), and the upper header transmitting unit 417 is a unit for transmitting the extracted upper header to the upper protocol executing unit.
[0048]
According to such a configuration, in addition to not transmitting the packet to the upper-level protocol execution unit 500 for the check bit error packet, the upper-level header is extracted and transmitted to the upper-level protocol execution unit 500. Even when an error occurs, the upper-layer protocol executing unit 500 can determine the attributes of the second and subsequent packets.
[0049]
When a check bit error occurs, the upper header is extracted and the upper header is transmitted to the upper protocol execution step. However, regardless of whether a check bit error occurs, the upper header is always extracted and transmitted. May be.
[0050]
In Embodiments 1 to 6, Ethernet (R) has been described as an example of the MAC layer protocol, but the present invention may be applied to MAC layer protocols other than Ethernet (R).
[0051]
In the first to sixth embodiments, a method and an apparatus have been described in which the Ethernet (R) header, the IP header, and the UDP header of a packet in which a check bit error has occurred are considered to be normal, but the IP header has a header. There is a checksum for confirming the reliability of the packet, and the received packet or the upper header is transmitted to the upper protocol execution step or the upper protocol execution means only when the IP header is correct using the checksum. Good.
[0052]
Although the first to sixth embodiments have been described independently, they may be used in combination.
[0053]
【The invention's effect】
As described above, according to the packet receiving method and the packet receiving apparatus of the present invention, in a packet communication network in which a bit error of a packet is unavoidable, a bit error of a leading packet of a fragment is generated without requiring an additional protocol for a transmitting terminal. Thus, even if a long packet having a size exceeding the protocol default is received, a packet receiving method and a packet receiving apparatus capable of suppressing disturbance of reproduced video and audio can be realized.
[Brief description of the drawings]
1 is a flowchart of a packet receiving method according to Embodiment 1 of the present invention; FIG. 2 is a flowchart of a packet receiving method according to Embodiment 2 of the present invention; FIG. 3 is a flowchart of a packet receiving method according to Embodiment 3 of the present invention; FIG. 4 is a flowchart of a packet receiving method according to Embodiments 1 to 3 of the present invention. FIG. 5 is a block diagram of a packet receiving apparatus according to Embodiment 4 of the present invention. FIG. 7 is a block diagram of a packet receiving device according to Embodiment 6 of the present invention. FIG. 8 is a block diagram of a packet receiving device according to Embodiments 4 to 6 of the present invention. Diagram showing relationship between hierarchical structure of model and UDP / IP / Ethernet (R)
110 packet reception determination step 111 check bit determination step 112 check bit notification step 113 video / audio data determination step 114 packet transmission step 115 end determination step 116 long packet determination step 117 long packet notification step 118 upper header extraction step 119 upper header transmission step 120 Packet discarding step 121 Packet transmission step 100 MAC layer protocol execution step 200 Upper protocol execution step 210 Network layer protocol execution step 220 Transport layer protocol execution step 410 Check bit determination means 411 Check bit error notification means 412 Packet transfer means 413 Video / audio data Judgment means 414 long packet judgment means 415 long packet notification means 416 Upper header extracting means 417 Upper header transmitting means 400 MAC layer protocol executing means 500 Upper protocol executing means 510 Network layer protocol executing means 520 Transport layer protocol executing means

Claims (6)

A packet receiving method comprising: a MAC layer protocol executing step of receiving a packet from a packet communication network and executing a MAC (media access control) layer protocol; and an upper protocol executing step of executing a protocol in a layer higher than the MAC layer. So,
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol execution step,
A packet reception determining step of determining that a packet has been received;
A check bit determining step of determining whether a bit error has occurred in the received packet using a check bit added to the received packet;
A check bit error notification step of notifying an error to the upper protocol execution step,
A video / audio data determining step of determining whether or not the received packet is transmitting video / audio data by inspecting a header of a protocol of a higher layer than a MAC layer; and transmitting the received packet to the upper protocol executing step. A packet transmission step,
An end determination step of determining the end of the operation,
The check bit error notification step, when it is determined that a bit error has occurred in the received packet in the check bit determination step, notifies a check bit error to the upper protocol execution step,
The video and audio data determination step is to execute a packet transmission step when it is determined that the received packet in which the check bit error has occurred is transmitting video and audio data, and to determine that the video and audio data is not being transmitted. Comprises a step of executing an end determination step. A packet receiving method comprising: receiving a packet from a packet communication network and executing a MAC layer protocol for executing a MAC layer protocol; and an upper protocol executing step for executing a protocol of a higher layer than the MAC layer.
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol execution step,
A packet reception determining step of determining that a packet has been received;
A long packet determining step of determining whether the packet size of the received packet exceeds a maximum packet size defined by a MAC layer protocol;
A long packet notification step of notifying the upper protocol execution step of a long packet reception,
A video / audio data determining step of inspecting a header of a protocol higher than a MAC layer to determine whether or not the received packet transmits video / audio data;
A packet transmitting step of transmitting the received packet to the upper-layer protocol executing step;
An end determination step of determining the end of the operation,
The video and audio data determination step, when it is determined that the received packet determined to exceed the maximum size in the long packet determination step is transmitting video and audio data, executes the packet transmission step, A packet receiving method, wherein when it is determined in the long packet determining step that the maximum size is not exceeded, the end determining step is performed. A packet receiving method comprising: receiving a packet from a packet communication network and executing a MAC layer protocol for executing a MAC layer protocol; and an upper protocol executing step for executing a protocol of a higher layer than the MAC layer.
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol execution step,
A packet reception determining step of determining that a packet has been received;
A check bit determining step of determining whether a bit error has occurred in the received packet using a check bit added to the received packet;
An upper header extraction step of extracting a header of a protocol higher than the MAC layer;
An upper header transmission step of transmitting the upper header extracted in the upper header extraction step to the upper protocol execution step,
A packet discarding step of discarding the received packet;
A packet transmitting step of transmitting the received packet to the upper-layer protocol executing step;
An end determination step of determining the end of the operation,
If it is determined that a bit error has occurred in the check bit determination step, execute the upper header extraction step, the upper header transmission step, and the packet discard step,
A packet receiving method, wherein the packet transmitting step is performed when it is not determined in the check bit determining step that a bit error has occurred. A packet receiving apparatus comprising: a MAC layer protocol executing unit that receives a packet from a packet communication network and executes a MAC layer protocol; and an upper layer protocol executing unit that executes a higher layer protocol than the MAC layer.
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol executing means,
Check bit determining means for determining whether or not a bit error has occurred in the received packet using a check bit added to the received packet,
Check bit error notification means for notifying a bit error to the upper protocol execution step,
Video / audio data determining means for inspecting a header of a protocol higher than the MAC layer to determine whether the received packet transmits video / audio data,
A packet transmission step of controlling transmission of the received packet to the upper layer protocol execution means,
The check bit determination unit outputs a check bit error signal to a packet transmission unit when a bit error occurs in the received packet,
The check bit error notification unit, when receiving a check bit error signal from the check bit determination unit, notifies the upper-layer protocol execution unit of a check bit error,
The video / audio data determination unit outputs a signal for determining whether the received packet is video / audio data to the packet transmission unit,
The packet transmitting means, if the received packet has a check bit error, or if a check bit error has occurred, and if it is video and audio data, to transmit the received packet to the upper protocol execution means. Characteristic packet receiving device. A packet receiving apparatus comprising: a MAC layer protocol executing unit that receives a packet from a packet communication network and executes a MAC layer protocol; and an upper layer protocol executing unit that executes a higher layer protocol than the MAC layer.
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol executing means,
Long packet determining means for determining whether the packet size of the received packet exceeds a maximum packet size defined by a MAC layer protocol,
Long packet notification means for notifying the high-order protocol execution means of reception of a long packet,
Video / audio data determining means for inspecting a header of a protocol higher than the MAC layer to determine whether the received packet transmits video / audio data,
Packet transmitting means for transmitting the received packet to the upper protocol execution means,
The long packet determination unit outputs a long packet reception signal to the packet transmission unit when the received packet is a long packet,
The long packet notification unit, when receiving a long packet reception signal from the long packet determination unit, notifies the upper protocol execution unit of the reception of a long packet,
The video / audio data determination unit outputs a signal for determining whether the received packet is video / audio data to the packet transmission unit,
The packet receiving device, wherein the packet transmitting unit transmits the received packet to the upper-layer protocol executing unit when the received packet is not a long packet or when the received packet is a long packet and video / audio data. A packet receiving apparatus comprising: a MAC layer protocol executing unit that receives a packet from a packet communication network and executes a MAC layer protocol; and an upper layer protocol executing unit that executes a higher layer protocol than the MAC layer.
The MAC layer protocol is a protocol that defines a method of accessing a communication medium and realizes communication between adjacent nodes using a physical address,
In the MAC layer protocol executing means,
Check bit determining means for determining whether or not a bit error has occurred in the received packet using a check bit added to the received packet,
Upper header extracting means for extracting a header of a protocol higher than the MAC layer;
Upper header transmitting means for transmitting the upper header extracted by the upper header extracting means to the upper protocol executing means,
Packet transmission means for controlling transmission of the received packet to the upper protocol execution means,
The check bit determining unit outputs a check bit error signal to the packet transmitting unit and the upper header transmitting unit when a bit error occurs in the received packet,
The upper header transmission means, when receiving a check bit error signal from the check bit determination means, to transfer the upper header to the upper protocol execution means,
The packet receiving device, wherein the packet transmitting unit transmits the received packet to the higher-level protocol executing unit when a check bit error signal is not received from the check bit determining unit.

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