JP2003085063A - Communication relay device and communication method - Google Patents

Abstract

(57) [Summary] [Problem] To enable relay using IP masquerade in communication using the H.323 protocol. A monitor unit (104) includes a packet transmitting / receiving unit (1).
Monitor the message content of the packet output from 01. Then, when a session is set in a layer higher than the transport layer and a port number is set, the monitor unit 104 notifies the updating unit 105 of the port number. When a session is set in a layer higher than the transport layer and a port number is set, the updating unit 105
In the IP masquerade table 106, the combination of the own address of the packet and the port number and the combination of the destination address and the port number are associated with each other.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a communication relay device and a communication method, and more particularly to a communication relay device and a communication method suitable for use in packet communication handling streaming data.

[0002]

2. Description of the Related Art In recent years, local area networks (LA
N: Local Area Network) has advanced network technology such as wide band, and personal computer (PC) has multiple functions and CPU (Ce) applied to PC.
PC including speedup of ntral processor unit)
As the technology advances, it has become practical to transmit voice information at high speed between PCs on a plurality of LANs.

Due to these technological advances, application software for executing conventional voice communication by telephone between PCs connected to the Internet using IP (Internet Protocol), and a hardware system incorporating this software. Are rapidly entering the market.

The H.264 standard is one of the standards for voice communication using IP. There are 323 protocols. H. The H.323 protocol is a protocol used for audiovisual communication operating on a QOS (Quality of Service) non-guaranteed LAN. FIG. It is a schematic diagram which shows the structure of 323 protocol.

H. In the H.323 protocol, the configuration below the transport layer is not specified, but the configuration above the session layer above the transport layer is specified. H. The H.323 protocol is used for packetizing multimedia information, synchronization, and RAS (Registration Admission Status).
tus), which defines call control. 225.0 protocol,
H.264 that defines control between terminals. 245 protocol.

In the following, H. A communication procedure using the H.323 protocol will be described. FIG. It is a sequence diagram which shows an example of the communication procedure using the H.323 protocol.
In FIG. 11, the originating IP communication terminal 11 requests voice communication from the terminating IP communication terminal 12 and requests RTP (Real-time Transpo
The procedure for establishing voice communication using the rt Protocol is shown below.

[0007] First, the originating IP communication terminal 11 uses the SETUP
The message is transmitted to the incoming IP communication terminal 12. This SE
The packet including the TUP message includes the sender's own address, own port number, destination address, and destination port number.

In FIG. 11, XI indicates the own address of the originating IP communication terminal 11, and XP indicates a port number used by the originating IP communication terminal 11 for controlling the voice communication. Further, YI indicates the address of the incoming IP communication terminal 12, and YP indicates the port number used by the incoming IP communication terminal 12 in controlling the voice communication.

Since the SETUP message is a message transmitted from the originating IP communication terminal 11 to the terminating IP communication terminal 12, the packet's own address is XI, its own port number is XP, the destination address is YI, and the destination port number is YP. It is set and sent. Similarly, a packet transmitted from the source IP communication terminal 11 to the destination IP communication terminal 12 is transmitted with its own address set to XI, its own port number set to XP, the destination address set to YI, and the destination port number set to YP. .

When the terminating IP communication terminal 12 receives the SETUP message, the terminating IP communication terminal 12 performs an incoming call process, and the originating IP communication terminal 1
Reply ALERT message to 1. The ALERT message is
Since this is a message sent from the incoming IP communication terminal 12 to the outgoing IP communication terminal 11, its own address is YI, its own port number is YP, the destination address is XI, and the destination port number is X.
It is transmitted in a packet in which P is set. Similarly, the packet transmitted from the incoming IP communication terminal 12 to the outgoing IP communication terminal 11 is YI for its own address and Y for its own port number.
P, XI is set in the destination address, and XP is set in the destination port number, and the packet is transmitted.

Then, the incoming IP communication terminal 12 sends a CONNECT message to the outgoing IP communication terminal 11 after preparation for response is completed. The originating IP communication terminal 11 is CONNEC
When the T message is received, it is determined that communication with the incoming IP communication terminal 12 is possible, and a TerminalCapabilitySet message is sent to the incoming IP communication terminal 12 to convey the capability of the terminal. Then, the incoming IP communication terminal 12 is the TerminalCapa
The bilitySetAck message is transmitted to the originating IP communication terminal 11 to convey the capability of the terminal.

After transmitting the capabilities of both terminals, a logical channel for transmitting a voice signal is set and transmitted to the other terminal.
Here, when transmitting an audio signal, RTP (Real Tim
e Transport Protocol) is used. RTP is a packet format for multimedia data streams, and is defined in H.264. Used for the data part of the H.323 protocol.

Specifically, the originating IP communication terminal 11 is
An enLogicalChannel message is sent to the incoming IP communication terminal 12, and the outgoing IP communication terminal 11 sends the incoming IP communication terminal 1
2 requests the setting of the logical channel used when transmitting a voice signal. The incoming IP communication terminal 12 is OpenLogica.
The lChannelAck message is returned to the originating IP communication terminal 11 and the port number used when transmitting the RTP packet is transmitted.

Further, the incoming IP communication terminal 12 is an OpenLogi
A calChannel message is sent to the originating IP communication terminal 11, and a request is made to set a logical channel used when a voice signal is transmitted from the terminating IP communication terminal 12 to the originating IP communication terminal 11. The originating IP communication terminal 11 is an OpenLogicalCha
The nnelAck message is returned to the incoming IP communication terminal 12,
Tells the port number to use when sending RTP packets.

After the port number used in RTP is set, voice communication is performed. Specifically, the originating IP communication terminal 11 sets the destination port number to VYP and transmits the voice signal as an RTP packet to the terminating IP communication terminal 12. Further, the incoming IP communication terminal 12 sets the destination port number to VXP and transmits the voice signal as an RTP packet to the outgoing IP communication terminal 11.

In this way, H.264 When voice communication is performed in accordance with the H.323 protocol, the port number used for communication until the voice communication is different from the port number used for voice communication.

Here, the terminals between different networks are H.264. When performing voice communication according to the H.323 protocol, changing the port number may make communication impossible. For example, IP masquerade (NAPT: Network Add
When relaying communication between two networks using ress Port Translation), TCP (Transmission Control Protocol) or UDP (U
ser Datagram Protocol) port number is converted.

FIG. It is a sequence diagram which shows an example of the communication procedure using the H.323 protocol. In FIG. 12, an outgoing IP communication terminal 21 is a terminal connected to a private LAN, and an incoming IP communication terminal 22 is a terminal connected to the Internet. Here, the private LAN and the Internet are connected by using the communication relay device 23 as a relay device.

IP masquerade is a private LAN
It is used when you want to communicate at the same time with a smaller number of Internet addresses (global addresses) than the number of addresses assigned to the terminals inside. If the number of simultaneous sessions is larger than the global address, the port number is changed for each session.

Hereinafter, with reference to FIG. 12, the originating IP communication terminal 21 receives the incoming IP communication terminal 2 via the communication relay device 23.
A procedure for requesting the voice communication from the user 2 and establishing the voice communication will be described. In FIG. 12, the address of the source IP communication terminal 21 is XI, the global address of the destination IP communication terminal 22 is YI, and the global address of the communication relay device 23 is X.
I '.

First, the originating IP communication terminal 21 sets up SETUP
The message is transmitted to the incoming IP communication terminal 22. This SE
The TUP message is sent from the outgoing IP communication terminal 21 to the incoming IP.
Since the message is sent to the communication terminal 22, its own address is XI, its own port number is XP, and the destination address is YI.
It is transmitted in a packet in which YP is set in the destination port number. Similarly, a packet transmitted from the originating IP communication terminal 21 to the terminating IP communication terminal 22 will have X at its own address.
I, XP is set to the own port number, YI is set to the destination address, and YP is set to the destination port number.

From the packet destination address, the communication relay device 23 determines that the packet of the SETUP message is not the packet for the terminal in the private LAN but the packet for the Internet. Then, the communication relay device 23 replaces the own address of the packet of the SETUP message with XI ', which is the address of the communication relay device 23, and replaces the own port number of the SETUP message with the port number XP not used by the communication relay device 23. Replace with ´.

Then, the communication relay device 23 transmits to the destination IP communication terminal 22 a SETUP message packet in which its own address and its own port number are replaced. Also, the communication relay device 23 uses the combination of the address and the port number (X
I, XP) and (XI ′, XP ′) are associated with each other
Remember in the masquerade table.

When the incoming IP communication terminal 22 receives the SETUP message, it performs incoming call processing. Since the own address of the packet of the SETUP message is the global address XI 'of the communication relay device 23, the incoming IP communication terminal 22 returns the ALERT message to the communication relay device 23.

Since the ALERT message is a message transmitted from the incoming IP communication terminal 22 to the communication relay device 23, the packet's own address is YI, its own port number is YP, the destination address is XI ', and the destination port number is XP
'Is set and transmitted. Similarly thereafter, the packet transmitted from the incoming IP communication terminal 22 to the communication relay device 23 is transmitted with YI set to its own address, YP set to its own port number, XI ′ set to the destination address, and XP ′ set to the destination port number. It

The communication relay device 23 refers to the IP masquerading table and searches for a combination corresponding to the destination address and the destination port number of the packet of the received ALERT message.

In the IP masquerading table, combinations of addresses and port numbers (XI, XP) and (XI ', X
P ′) is associated with the communication relay device 2
3 is the destination address of the packet of the ALERT message is X
I'is replaced by XI, and the destination port number of the ALERT message is replaced by XP 'by XP.

Then, the communication relay device 23 transmits the ALERT message in which the destination address and the destination port number are replaced to the originating IP communication terminal 21 in the private LAN. Similar to the ALERT message, the CONNECT message is also transmitted from the incoming IP communication terminal 22 to the outgoing IP communication terminal 21 through the communication relay device 23.

After that, the communication relay device 23 sets I to the own address and the own port number of the packet of the message transmitted from the originating IP communication terminal 21 to the terminating IP communication terminal 22.
The P masquerade table is referred to, converted, and transmitted to the incoming IP communication terminal 22 via the Internet.

Further, the communication relay device 23 sets I to the destination address and destination port number of the packet of the message transmitted from the incoming IP communication terminal 22 to the communication relay device 23.
The P masquerade table is referred to, converted, and transmitted to the originating IP communication terminal 21 in the private LAN.

By the above processing, TerminalCapabilitySet
Message, TerminalCapabilitySetAck Message, Op
enLogicalChannel message and OpenLogicalChannel
The Ack message is converted from the address and port number of the packet exchanged between the originating IP communication terminal 21 and the terminating IP communication terminal 22.

Here, the source IP communication terminal 21 and the destination IP
The communication terminal 22 uses the OpenLogicalChannel message and the Op
By exchanging enLogicalChannelAck messages, R
The partner terminal is notified of the port number used when transmitting the TP packet.

The originating IP communication terminal 21 sets the destination port number to VYP and transmits the voice signal as an RTP packet to the terminating IP communication terminal 22 via the communication relay device 23. The communication relay device 23 converts the own address of the RTP packet from XI to XI ′, the own port number from XP to XP ′, and transmits the RTP packet to the incoming IP communication terminal 22.

Then, the incoming IP communication terminal 22 sets the destination port number to VXP and transmits the voice signal to the communication relay device 23 as an RTP packet. The communication relay device 23 is
Received RTP by referring to the IP masquerade table
Search for a combination that corresponds to the destination address and destination port number of the packet.

[0035]

However, since the data corresponding to the combination of the address and the port number (XI ', VXP) is not registered in the IP masquerading table, the communication relay device 23 determines that the RTP packet The destination cannot be determined and is discarded.

As described above, in the conventional device, the
In communication using the H.323 protocol, there is a problem that relay using IP masquerade cannot be performed.

The present invention has been made in view of the above point, and is described in H.264. IP in communication using the H.323 protocol
An object of the present invention is to provide a communication relay device and a communication method capable of relaying using masquerade.

[0038]

A communication relay apparatus of the present invention stores a session table in which a session used in a first network and a session used in a second network are associated with each other, and according to the session table. , Conversion means for converting sessions used in the first and second networks to each other, monitoring means for monitoring session information set in a layer above the transport layer, and a layer above the transport layer When the set session is monitored, the session table is updated as a session having the session as a service common to the first and second networks, and an updating unit that updates the session table.

According to this configuration, the information of the session set in the layer above the transport layer is reflected in the conversion of the session performed in the transport layer, so that the H.264 standard is reflected. In communication using the H.323 protocol, relay using IP masquerade can be performed.

In the communication relay device of the present invention, the monitor means is
A configuration is adopted in which the received packet is monitored and session information set in a layer above the transport layer is extracted.

According to this configuration, by reflecting on the session conversion performed in the transport layer, based on the session setting information notified from the communication terminal device,
H. In communication using the H.323 protocol, relay using IP masquerade can be enabled.

In the communication relay device of the present invention, the storage means stores the combination of the address and port number used in the first network and the combination of the address and port number used in the second network in the session table, and the conversion means is , The addresses and port numbers used in the first and second networks are mutually converted according to the session table, and the monitoring means monitors information of a session set in a layer higher than the transport layer,
The updating unit adopts a configuration in which the port number used in the first network and the port number used in the second network are associated with the same number for the session and updated.

According to this configuration, the information in the layers above the transport layer is monitored, and the destination port number used in the transport layer when transmitting a packet is detected,
When the packet to be relayed uses this destination port, the H.264 packet is converted by performing the address conversion without converting the port number. In communication using the H.323 protocol, relay using IP masquerade can be enabled.

The communication terminal device of the present invention comprises second monitor means for monitoring session information set in a layer above the transport layer for received packets, and a layer set above the transport layer. And transmitting means for transmitting information of the session to the communication relay device.

According to this structure, when the received packet includes the information for notifying the destination port number used in the transport layer, it is possible to notify the communication relay device that the destination port is used. .

According to the communication method of the present invention, in communication for converting information defining a session and relaying a packet exchanged between two networks, a service is provided to a session set in a layer higher than a transport layer. The information defining the address is not converted, but the information defining the address is converted and the packet is relayed.

According to this method, the information of the session set in the layer higher than the transport layer is reflected in the conversion of the session performed in the transport layer, so that the H.264 standard is reflected. In communication using the H.323 protocol, relay using IP masquerade can be performed.

[0048]

BEST MODE FOR CARRYING OUT THE INVENTION When transmitting stream data such as RTP in packets in communication using the H.323 protocol, a session is set in a layer higher than the transport layer, and a destination port number for identifying a service used in the transport layer is a transport layer. The present invention has been completed, paying attention to the fact that notification is made by higher layers.

That is, the essence of the present invention is to reflect the session information set in a layer higher than the transport layer in the session conversion performed in the transport layer, specifically, by using IP masquerade. When translating an address and a port number, by registering the destination port number notified by a layer higher than the transport layer in the IP masquerade table and setting it as the target of the address translation, the destination address of the packet is translated. is there.

(Embodiment 1) The communication relay apparatus according to the present embodiment monitors information in layers above the transport layer and detects a destination port number used in the transport layer when transmitting a packet. . Then, when using this destination port, the communication relay device of the present embodiment relays the packet by translating the address without translating the port number.

FIG. 1 is a block diagram showing the configuration of the communication relay apparatus according to the first embodiment of the present invention. The communication relay device 100 of FIG. 1 is a device such as a router or a gateway that converts an address and a port number of a packet exchanged between two networks. The communication relay device 100 of FIG.
Is a packet transmission / reception unit 101 and an address conversion unit 102.
The packet transmission / reception unit 103, the monitor unit 104, the update unit 105, and the IP masquerade table 106 are mainly included.

In FIG. 1, the packet transmitting / receiving unit 101
Receives a packet transmitted from the source IP communication terminal, outputs a header including control data to the address conversion unit 102, and outputs a payload, which is a field for transmitting actual data, to the packet transmission / reception unit 103. The packet transmitting / receiving unit 101 also outputs the packet transmitted from the originating IP communication terminal to the monitor unit 104.

The address conversion unit 102 refers to the IP masquerade table 106 to convert the own address and the own port number included in the header output from the packet transmission / reception unit 101, and converts the converted header into the packet transmission / reception unit 1
Output to 03. Further, the address translation unit 102 uses the IP
By referring to the masquerading table 106, the own address and the own port number included in the header output from the packet transmitting / receiving unit 103 are converted, and the converted header is output to the packet transmitting / receiving unit 101.

The packet transmitting / receiving unit 103 adds the header output from the address converting unit 102 to the payload output from the packet transmitting / receiving unit 101 to generate a packet, and outputs the packet to the incoming IP communication terminal. It also receives a packet output from the incoming IP communication terminal, outputs a header including control data to the address conversion unit 102, and outputs a payload, which is a field for transmitting actual data, to the packet transmission / reception unit 101.

The monitor unit 104 includes a packet transmitting / receiving unit 10
The message contents of the packet output from 1 are monitored. Then, when the session is set in a layer higher than the transport layer and the port number is set, the monitor unit 104 notifies the updating unit 105 of the port number.

For example, if the message is ASN. 1 (Abstra
ct Syntax Notation One), the monitor unit 104 determines that the ASN. Parses the message according to the encoding rule of 1.

When the session is set in a layer higher than the transport layer and the port number is set, the updating unit 105 determines the combination of the own address and the port number of the packet, the destination address and the port number. The combinations are associated and stored in the IP masquerade table 106.

The IP masquerade table 106 is a session table for storing the session of the network to which the originating IP communication terminal belongs and the session of the network to which the terminating IP communication terminal belongs in association with each other. Specifically, the IP masquerade table 106 stores the combination of the address and port number of the network to which the originating IP communication terminal belongs and the combination of the address and port number of the network to which the terminating IP communication terminal belongs.

FIG. 2 is a diagram showing an example of the conversion table provided in the communication relay device according to the present embodiment. The conversion table of FIG. 2 is a conversion table used by the IP masquerade table 106 of the communication relay device 100. In the conversion table of FIG. 2, a combination of a private LAN network address number and a port number is associated with a one-to-one correspondence with a combination of the Internet address number and a port number.

In FIG. 2, the combination of the address 192.168.0.50 and the port number 49152 in the private LAN,
Corresponds to the combination of the address 133.52.26.100 and the port number 61952 on the Internet. For example, when the combination of the own address and the own port number of the packet transmitted from the private LAN to the Internet is the address 192.168.0.50 and the port number 49152 registered in the conversion table, the address conversion unit 102 determines that It replaces its own port number with the address 133.52.226.100 and port number 61952 and sends the packet to the Internet.

Further, from the Internet, the communication relay device 1
The combination of the destination address and the destination port number of the packet transmitted to 00 is registered in the conversion table.133.
When the port number is 52.26.100 and the port number is 61952, the address conversion unit 102 sets the destination address and the destination port number to the address.
Replace 192.168.0.50 with port number 49152 and send the packet to the private LAN.

Then, the monitor unit 104 monitors the message content of the packet, and if the session is set in a layer higher than the transport layer and the port number is set, the own address of the packet and the port number of the packet are set. The combination and the combination of the destination address and the port number are associated and stored in the conversion table.

In FIG. 2, a combination of the address 192.168.0.50 and the port number 65535 in the private LAN,
Corresponds to the combination of the address 133.52.26.100 and the port number 65535 on the Internet.

For example, when the combination of the own address and the own port number of the packet transmitted from the private LAN to the Internet is the address 192.168.0.50 and the port number 65535 registered in the conversion table, the address conversion unit 102 Own address is 133.52.26.210
Replace it with 0 and send the packet to the Internet without changing its own port number as 65535.

Next, the operation of the communication relay device 100 will be described. FIG. 3 is a flowchart showing an example of the operation of the communication relay device according to the present embodiment. Here, an example will be described in which a packet transmitted from a source IP communication terminal in a private LAN is transmitted to the Internet.

In FIG. 3, in step (hereinafter referred to as “ST”) 301, the packet transmission / reception unit 101 causes the transmission I
It is determined whether there is a packet transmitted from the P communication terminal.
If there is a packet transmitted from the originating IP communication terminal, the process proceeds to ST302 and the packet is analyzed. S
At T302, the message content of the packet received by the monitor unit 104 is analyzed.

In ST303, it is determined whether or not the message content of the packet includes a notification of a port number used for real-time transmission of a voice signal or the like. If the message contents of the packet include notification of the port number, ST
In step 304, the conversion table is updated. If the message content of the packet does not indicate the port number, the process proceeds to ST305 and the packet address and port number are converted.

In ST304, updating section 105 updates IP masquerade table 106 based on the port number information included in the packet message. ST30
In 5, the address conversion unit 102 refers to the IP masquerade table and obtains correspondence information of the combination of the private LAN address and port number and the Internet address and port number.

In ST306, the address conversion unit 102
However, whether the combination of the destination address of the packet received by the packet transmitting / receiving unit 103 and the destination port number matches the reference content of the IP masquerade table 106, that is, whether the packet address and port number are converted. Judge whether or not. Packet address,
If the port number is to be converted, proceed to ST307. If the packet address and port number are not to be converted, ST30
Proceed to 9.

In ST307, address translation section 102 translates the packet address and port number. ST30
In 8, the packet transmission / reception unit 101 transmits the packet with the converted address and port number to the private LAN, and the processing ends. In ST309, the packet transmitting / receiving unit 1
01 discards the packet and does not send it. Then, the process ends.

Next, a procedure for establishing voice communication via the communication relay device 100 described above will be described. Figure 4
FIG. 6 is a sequence diagram showing an example of signal exchange of the communication relay device according to the present embodiment.

In FIG. 4, the source IP communication terminal 401 has an address XI, the destination IP communication terminal 402 has a global address YI, and the communication relay device 100 has a global address XI '.

First, the originating IP communication terminal 401 is set to SETU.
The P message is transmitted to the incoming IP communication terminal 402. Since this SETUP message is a message transmitted from the originating IP communication terminal 401 to the terminating IP communication terminal 402,
The packet to be transmitted is transmitted with its own address set to XI, its own port number set to XP, the destination address set to YI, and the destination port number set to YP. Similarly thereafter, the originating IP communication terminal 4
The packet transmitted from 01 to the incoming IP communication terminal 402 has its own address set to XI, its own port number set to XP, the destination address set to YI, and the destination port number set to YP.

The communication relay device 100 determines from the destination address of the packet of this SETUP message that the packet is not for the terminals in the private LAN but for the Internet. Then, the communication relay device 100 determines that the own address of the SETUP message packet is XI ', which is the address of the communication relay device 100.
, And replaces its own port number in the SETUP message with a port number XP ′ that is not used by the communication relay device 100.

Then, the communication relay device 100 transmits the packet of the SETUP message in which the own address and the own port number are replaced to the incoming IP communication terminal 402. Further, the communication relay device 100 stores the combination (XI, XP) of the address and the port number and (XI ′, XP ′) in association with each other in the IP masquerade table.

After that, the communication relay device 100 analyzes the content of the message transmitted from the source IP communication terminal 401 to the destination IP communication terminal 402, and informs the partner terminal of the port number used when transmitting the RTP packet in the message. Determine whether the content is included. Specifically, in the communication relay device 100, the content of the packet transmitted from the originating IP communication terminal 401 to the terminating IP communication terminal 402 is Open.
Determine if it is a LogicalChannelAck message.

When the incoming IP communication terminal 402 receives the SETUP message, it performs incoming call processing. Since the own address of the SETUP message is the global address XI ′ of the communication relay device 100, the incoming IP communication terminal 402 returns the ALERT message to the communication relay device 100.

Here, since the ALERT message is a message transmitted from the incoming IP communication terminal 402 to the communication relay device 100, the own address of the packet to be transmitted is YI,
The self port number is set to YP, the destination address is set to XI ', and the destination port number is set to XP', and then transmitted. Similarly after that,
The packet transmitted from the incoming IP communication terminal 402 to the communication relay device 100 is YI for its own address, YP for its own port number, XI 'for the destination address, and XP' for the destination port number.
Is set and sent.

The communication relay device 100 refers to the IP masquerade table and searches for a combination corresponding to the destination address and the destination port number of the packet of the received ALERT message. The combination of address and port number (XI, XP) in the IP masquerade table,
(XI ′, XP ′) are associated with each other, the communication relay device 100 replaces the destination address of the packet of the ALERT message from XI ′ to XI, and sets the destination port number of the packet of the ALERT message from XP ′. Replace with XP.

Then, the communication relay device 100 transmits the packet of the ALERT message in which the destination address and the destination port number are replaced, to the originating IP communication terminal 4 in the private LAN.
Send to 01. Similar to the ALERT message, the CONNECT message is also transmitted from the incoming IP communication terminal 402 to the communication relay device 1
00 is relayed and transmitted to the originating IP communication terminal 401.

After that, the communication relay device 100 refers to the IP masquerade table for conversion of the own address and the own port number of the packet of the message transmitted from the originating IP communication terminal 401 to the terminating IP communication terminal 402, and converts it to the Internet. To the incoming IP communication terminal 402 via.

Further, the communication relay device 100 converts the destination address and the destination port number of the packet of the message transmitted from the incoming IP communication terminal 402 to the communication relay device 100 by referring to the IP masquerade table to convert the private LAN. To the originating IP communication terminal 401.

By the above processing, TerminalCapabilitySet
Message, TerminalCapabilitySetAck Message, Op
enLogicalChannel message and OpenLogicalChannel
Regarding the Ack message, the address and port number of the packet exchanged between the originating IP communication terminal 401 and the terminating IP communication terminal 402 are converted.

Here, the source IP communication terminal 401 and the destination I
The P communication terminal 402 notifies the partner terminal of the port number used when transmitting the RTP packet by exchanging the OpenLogicalChannel message and the OpenLogicalChannelAck message.

The originating IP communication terminal 401 sets the destination port number to VYP and transmits the voice signal as an RTP packet to the terminating IP communication terminal 402 via the communication relay device 100. The communication relay device 100 converts the own address of the RTP packet from XI to XI ′, the own port number from XP to XP ′, and the RTP packet to the incoming IP.
It is transmitted to the communication terminal 402.

Then, the incoming IP communication terminal 402 sets the destination port number to VXP and transmits the voice signal to the communication relay device 100 as an RTP packet. The communication relay device 100 refers to the IP masquerading table and searches for a combination corresponding to the destination address and the destination port number of the received RTP packet.

The communication relay device 100 converts the destination address of this RTP packet from XI 'to XI. Then, the communication relay device 100 does not change the destination port number as VXP. The communication relay device 100 transmits the RTP packet whose destination address has been changed to the originating IP communication terminal 401 in the private LAN.

As described above, according to the communication relay device of the present embodiment, the information of the layers above the transport layer is monitored, and the destination port number used in the transport layer when transmitting a packet is detected. , When the packet to be relayed uses this destination port, the H.264 packet is converted by performing the address conversion without converting the port number. In communication using the H.323 protocol, relay using IP masquerade can be enabled.

In this embodiment, the private L
Although an example of relaying between the AN and the Internet has been described, the present invention is not limited to this, and the same effect can be obtained as long as the packet is relayed between two networks.

(Embodiment 2) In the communication terminal apparatus of this embodiment, when the received packet includes information notifying the destination port number used in the transport layer,
The communication relay device of this embodiment is notified that this destination port will be used, and the communication relay device of this embodiment receives this notification, and when using this destination port, it converts the port number. Instead, it performs address translation and relays the packet.

FIG. 5 is a block diagram showing the configuration of the communication terminal apparatus according to Embodiment 2 of the present invention. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.

First, the originating IP communication terminal 500 will be described. In FIG. 5, the network interface unit 501 receives the packet transmitted from the communication relay device and outputs the content of the packet to the receiving unit 502. The receiving unit 502 analyzes the message included in the received packet and outputs the analysis result to the control unit 503.

The control unit 503 instructs the communication opening procedure of the RTP protocol according to the analysis result of the message output from the receiving unit 502, and outputs the content of the packet to be transmitted to the transmitting unit 504. Further, when the analysis result of the message includes the information of the destination port number used in the data streaming using RTP, the control unit 503 outputs the information of the destination port number to the port number information transmitting unit 50.
Output to 5.

The transmission unit 504 outputs the contents of the packet to be transmitted according to the instruction of the control unit 503 to the network interface unit 501.

The port number information transmitting unit 505 is the control unit 5
When the information about the destination port number is transmitted from 03, the destination port number is output to the communication relay device 700 via the network interface unit 501 as information indicating that the destination port number is used in data streaming using RTP.

The operation of the originating IP communication terminal 500 will be described using a flow chart. FIG. 6 is a flowchart showing the operation of the communication terminal apparatus according to this embodiment. Here, an example will be described in which a packet transmitted from a source IP communication terminal in a private LAN is transmitted to the Internet.

In FIG. 6, in ST601, network interface section 501 determines whether there is a packet transmitted from the communication relay device. Then, if there is a packet transmitted from the communication relay device, the process proceeds to ST302 and the packet is analyzed. In ST602, the message content of the packet received by receiving section 502 is analyzed.

In ST603, control section 503 determines whether or not the message contents of the packet include notification of a port number used for real-time transmission of a voice signal or the like. If the message content of the packet includes the notification of the port number, the process proceeds to ST604, and the communication relay device is notified of the port number. Also, in the message content of the packet,
If there is no notification of the port number, the process proceeds to ST605 and packet transmission is performed.

In ST604, port number information transmitting section 5
05 outputs the information of the destination port number used for the real-time transmission of the audio signal to the communication relay device via the network interface unit 501. In ST605, transmitting section 504 transmits the packet.

As described above, when the received packet includes the information notifying the destination port number used in the transport layer, the communication terminal apparatus of the present embodiment is It is possible to notify that this destination port will be used.

Next, the communication relay device of the present embodiment will be described. FIG. 7 is a block diagram showing the configuration of the communication relay device according to the present embodiment. However, the same components as those in FIG. 1 are denoted by the same reference numerals as those in FIG. 1, and detailed description thereof will be omitted.

The communication relay device 700 of FIG. 7 comprises a packet transmission / reception unit 701 and a port number information transmission unit 702, and based on the information of the use of the destination port notified from the originating IP communication terminal 500, this destination When using a port, perform address translation without performing port number translation,
The point that a packet is relayed is different from the communication relay device of FIG.

In FIG. 7, a packet transmission / reception unit 701.
Receives the packet transmitted from the originating IP communication terminal 500, and converts the header including the control data into the address conversion unit 1
02, and the payload, which is a field for transmitting actual data, is output to the packet transmitting / receiving unit 103. Also,
The packet transmitting / receiving unit 701 outputs the packet transmitted from the originating IP communication terminal 500 to the port number information transmitting unit 702.

The port number information transmitting section 702 extracts the information of the destination port number used for real-time transmission of the voice signal from the packet and outputs it to the updating section 105.

The updating unit 105 includes the port number information transmitting unit 7
When the information of the destination port number used for real-time transmission of the voice signal is output from 02, the IP masquerade table is created by associating the combination of the own address of the packet and the port number with the combination of the destination address and the port number. It is stored in 106.

The address conversion unit 102 refers to the IP masquerade table 106, converts the own address and the own port number included in the header output from the packet transmission / reception unit 701, and outputs them to the packet transmission / reception unit 103. Further, the address conversion unit 102 refers to the IP masquerade table 106, converts the own address and the own port number included in the header output from the packet transmission / reception unit 103, and outputs them to the packet transmission / reception unit 701.

The packet transmission / reception unit 103 adds the header output from the address conversion unit 102 to the payload output from the packet transmission / reception unit 701 to generate a packet, and outputs the packet to the incoming IP communication terminal. It also receives a packet output from the incoming IP communication terminal, outputs a header containing control data to the address conversion unit 102, and outputs a payload, which is a field for transmitting actual data, to the packet transmission / reception unit 701.

The IP masquerading table 106 stores the combination of the address and port number of the network to which the originating IP communication terminal belongs and the combination of the address and port number of the network to which the terminating IP communication terminal belongs.

Next, the operation of communication relay apparatus 700 will be described. FIG. 8 is a flow chart showing an example of the operation of the communication relay device according to the present embodiment. Here, an example will be described in which a packet transmitted from a source IP communication terminal in a private LAN is transmitted to the Internet.

In ST801 in FIG. 8, packet transmitting / receiving section 701 determines whether there is a packet transmitted from originating IP communication terminal 500. If there is a packet transmitted from the originating IP communication terminal 500, ST8
In step 02, the packet is analyzed. In ST802,
The port number information transmitting unit 702 makes the originating IP communication terminal 500
Information of a destination port number used for real-time transmission of a voice signal or the like is taken out from the packet transmitted from and output to the port number information transmitting unit 702.

In ST803, it is determined whether or not the message contents of the packet include notification of a port number used for real-time transmission of a voice signal. If the message contents of the packet include notification of the port number, ST
In step 804, the conversion table is updated. If the message content of the packet does not indicate the port number, the process proceeds to ST805 and the packet address and the port number are converted.

In ST804, updating section 105 updates IP masquerading table 106 based on the information of the port number used in the message of the packet.
In ST805, address conversion section 102 refers to the IP masquerade table and obtains correspondence information of the combination of the private LAN address and port number and the Internet address and port number.

In ST806, the address conversion unit 102
However, whether the combination of the destination address of the packet received by the packet transmitting / receiving unit 103 and the destination port number matches the reference content of the IP masquerade table 106, that is, whether the packet address and port number are converted. Judge whether or not. Packet address,
If the port number is to be converted, proceed to ST807. If the packet address and port number are not to be converted, ST80.
Proceed to 9.

In ST807, address conversion section 102 converts the address and port number of the packet. ST80
In 8, the packet transmitting / receiving unit 701 transmits the packet in which the address and the port number are converted to the private LAN and ends the processing. In ST809, the packet transmitting / receiving unit 7
01 discards the packet and does not send it. Then, the process ends.

Next, a procedure for establishing voice communication via the communication relay device 700 described above will be described. Figure 9
FIG. 6 is a sequence diagram showing an example of signal exchange of the communication relay device according to the present embodiment.

In FIG. 9, the source IP communication terminal 500 has an address XI, the destination IP communication terminal 402 has a global address YI, and the communication relay device 700 has a global address XI '.

First, the originating IP communication terminal 500 sets the SETU
The P message is transmitted to the incoming IP communication terminal 402. Since this SETUP message is a message transmitted from the originating IP communication terminal 500 to the terminating IP communication terminal 402,
The packet is transmitted with its own address set to XI, its own port number set to XP, the destination address set to YI, and the destination port number set to YP. Similarly, thereafter, the packet transmitted from the originating IP communication terminal 500 to the terminating IP communication terminal 402 is XI for its own address, XP for its own port number, and Y for its destination address.
I, YP is set to the destination port number.

The communication relay device 700 sends a message from the destination address of this SETUP message to the private LA.
It is determined that the message is not for the terminals in N but for the Internet. Then, the communication relay device 7
00 indicates the own address of the packet of the SETUP message as X
I is replaced with XI ′ which is the address of the communication relay device 700, and the own port number of the packet of the SETUP message is a port number XP ′ that is not used by the communication relay device 700.
Replace with.

Then, the communication relay device 700 transmits a SETUP message in which the own address and the own port number are replaced to the incoming IP communication terminal 402. In addition, the communication relay device 7
00 is a combination of address and port number (XI, X
P) and (XI ′, XP ′) are associated with each other and stored in the IP masquerade table.

When the incoming IP communication terminal 402 receives the SETUP message, it performs incoming processing. Since the own address of the SETUP message is the global address XI ′ of the communication relay device 700, the incoming IP communication terminal 402 returns the ALERT message to the communication relay device 700.

Since the ALERT message is a message transmitted from the incoming IP communication terminal 402 to the communication relay device 700, YI is used as its own address and Y is used as its own port number.
P, XI 'is set in the destination address, and XP' is set in the destination port number, and the packet is transmitted. Similarly, a message transmitted from the incoming IP communication terminal 402 to the communication relay device 700 is transmitted with the own address set to YI, the own port number set to YP, the destination address set to XI ', and the destination port number set to XP'. It

The communication relay device 700 refers to the IP masquerading table and searches for a combination corresponding to the destination address and destination port number of the received ALERT message.

In the IP masquerade table, the combination of address and port number (XI, XP) and (XI ', X
P ′) is associated with the communication relay device 7
00 replaces the destination address of the ALERT message from XI ′ to XI and replaces the destination port number of the ALERT message from XP ′ to XP.

Then, the communication relay device 700 transmits the ALERT message in which the destination address and the destination port number are replaced to the originating IP communication terminal 500 in the private LAN. Similar to the ALERT message, the CONNECT message is also transmitted from the incoming IP communication terminal 402 to the outgoing IP communication terminal 500 through the communication relay device 700.

Thereafter, the communication relay device 700 refers to the IP masquerade table to convert the own address and the own port number of the message transmitted from the originating IP communication terminal 500 to the terminating IP communication terminal 402, and converts the message via the Internet. To the incoming IP communication terminal 402.

Further, the communication relay device 700 converts the destination address and the destination port number of the message transmitted from the incoming IP communication terminal 402 to the communication relay device 700 by referring to the IP masquerade table and converting the private L
It is transmitted to the originating IP communication terminal 500 in the AN.

By the above processing, TerminalCapabilitySet
Message, TerminalCapabilitySetAck Message, Op
enLogicalChannel message and OpenLogicalChannel
For the Ack message, the address and port number of the packet of the message exchanged between the originating IP communication terminal 500 and the terminating IP communication terminal 402 are converted.

Here, the outgoing IP communication terminal 500 and the incoming call I
The P communication terminal 402 notifies the partner terminal of the port number used when transmitting the RTP packet by exchanging the OpenLogicalChannel message and the OpenLogicalChannelAck message.

Then, the originating IP communication terminal 500 transmits a message of information on the port number used in RTP to the communication relay device 700. The communication relay device 700 updates the IP masquerade table according to this message.

The originating IP communication terminal 500 sets the destination port number to VYP and transmits the voice signal as an RTP packet to the terminating IP communication terminal 402 via the communication relay device 700. The communication relay device 700 converts the own address of the RTP packet from XI to XI ′, the own port number from XP to XP ′, and the RTP packet to the incoming IP.
It is transmitted to the communication terminal 402.

Then, the incoming IP communication terminal 402 sets the destination port number to VXP and transmits the voice signal as an RTP packet to the communication relay device 700. The communication relay device 700 refers to the IP masquerade table and searches for a combination corresponding to the destination address and the destination port number of the received RTP packet.

The communication relay device 700 converts the destination address of this RTP packet from XI 'to XI. Then, the communication relay device 700 does not change the destination port number as VXP. The communication relay device 700 transmits the RTP packet with the destination address changed to the originating IP communication terminal 500 in the private LAN.

As described above, according to the communication relay device of the present embodiment, when this destination port is used based on the use information of the destination port notified from the communication terminal device,
By translating the address without translating the port number and relaying the packet, H.264. In communication using the H.323 protocol, relay using IP masquerade can be enabled.

In the present embodiment, private L
Although an example of relaying between the AN and the Internet has been described, the present invention is not limited to this, and the same effect can be obtained as long as the packet is relayed between two networks.

[0135]

As described above, according to the communication relay device and the communication method of the present invention, the session information set in the layer higher than the transport layer is reflected in the session conversion performed in the transport layer. By letting
H. In communication using the H.323 protocol, relay using IP masquerade can be performed.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of a communication relay device according to a first embodiment of the present invention.

FIG. 2 is an example of a conversion table provided in the communication relay device according to the above embodiment.

FIG. 3 is a flowchart showing an example of the operation of the communication relay device according to the above embodiment.

FIG. 4 is a sequence diagram showing an example of exchange of signals of the communication relay device according to the above embodiment.

FIG. 5 is a block diagram showing a configuration of a communication terminal apparatus according to Embodiment 2 of the present invention.

FIG. 6 is a flowchart showing the operation of the communication terminal apparatus according to the above embodiment.

FIG. 7 is a block diagram showing a configuration of a communication relay device according to the above embodiment.

FIG. 8 is a flowchart showing an example of the operation of the communication relay device according to the above embodiment.

FIG. 9 is a sequence diagram showing an example of exchange of signals of the communication relay device according to the above embodiment.

FIG. Schematic diagram showing the configuration of the H.323 protocol

11: H. Sequence diagram showing an example of a communication procedure using the H.323 protocol

FIG. 12: H. Sequence diagram showing an example of a communication procedure using the H.323 protocol

[Explanation of symbols]

101, 103, 701 Packet transmitter / receiver 102 address converter 104 monitor 105 Update Department 106 IP Masquerade Table 501 network interface section 502 Receiver 503 control unit 504 transmitter 505 and 702 Port number information transmitter

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuma Kobayashi             2640 Nishinoura, Renjima-cho, Kurashiki City, Okayama Prefecture Kurashiki Arts             Faculty of Industrial Science and Technology, University of Science F-term (reference) 5B085 AC11 BC00                 5B089 GA31 GB01 HB10 KB06 KC15                       KC53 KG03 KG05                 5K033 AA05 BA14 CB09 DB18 EA02                       EC04

Claims (5)

[Claims] 1. Storage means for storing a session table in which a session used in the first network and a session used in the second network are associated with each other, and sessions used in the first and second networks according to the session table. Conversion means for converting between each other, a monitoring means for monitoring information of a session set in a layer higher than the transport layer, and a session set in a layer higher than the transport layer, if the session concerned is monitored. And a means for updating the session table as a session having the service as a service common to the first and second networks. 2. The communication relay device according to claim 1, wherein the monitoring unit monitors the received packet and extracts information on a session set in a layer above the transport layer. 3. The first storage means is provided in the session table.
The combination of the address and the port number used in the network and the combination of the address and the port number used in the second network are stored, and the conversion means stores the address and the port number used in the first and second networks according to the session table. And the monitoring unit monitors information of a session set in a layer higher than the transport layer, and the updating unit uses the port number used in the first network and the second network for the session. The communication relay device according to claim 1 or 2, wherein the port number and the port number are associated with each other and updated. 4. The second monitoring means for monitoring the information of the session set in the layer above the transport layer for the received packet, and the information of the session set in the layer above the transport layer are communicated. A communication terminal device, comprising: a transmission unit that transmits to a relay device. 5. In communication for converting information defining a session and relaying packets exchanged between two networks, information defining a service is provided for a session set in a layer higher than a transport layer. A communication method characterized in that the information defining an address is converted and the packet is relayed without being converted.