JP2004320341A - Packet relaying method and system between networks - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To relay packets in cooperation with a network interconnector and a signal processor, even if address information are dynamically determined during communication. <P>SOLUTION: A network interconnector 30 requests a signal processor 40 to process packets, as specified, if some of the packets meet conditions of a condition information table 34. Each entry of the condition information table 34 is added, if a processing condition flag involved in a registration request message about the address from the signal processor 40 is on. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a technology in which an inter-network connecting device interconnecting a plurality of packet networks relays a packet in cooperation with a signal processing device, and in particular, an inter-network connecting device relays a packet related to communication including a plurality of flows. About technology.
[0002]
[Prior art]
An inter-network connecting device that connects a plurality of packet networks may not only relay a packet but also have various functions such as address conversion and packet filtering. Hereinafter, a conventional technique will be described by taking an example of an inter-network connection device having an address translation function.
[0003]
When receiving a packet from one packet network, the conventional network connecting device rewrites the source address or the destination address described in the packet in accordance with a conversion table stored in a storage device, and converts this IP packet into another IP address. Relay to packet network. The translation table has a set of a source address and a destination address as one entry. If there is no entry in the translation table at the time of relaying, a new translation address is paid out and this address is added to the translation table. I do. In the above description, the “address” is a pair of an IP address and a UDP port number for a UDP / IP packet, a pair of a TCP / IP packet IP address and a TCP port number, and is used for other IP packets. IP address. The above technology is called NAPT (Network Address Port Translation) or IP masquerade. According to the network connecting device, it is possible to effectively use the IP address resources and to conceal the computers under the network connecting device.
[0004]
By the way, in such an inter-network connection device, as for a packet related to a higher-level protocol in which an IP address or a port number is embedded in a message stored in a TCP packet or a UDP packet, only the address information of the IP header, the TCP header, and the UDP header Is converted, there is a problem that an address mismatch occurs when an upper layer protocol exchanges an IP address or a port number. For example, in SIP (Session Initiation Protocol / RFC3261 and RFC2543), since the IP address and the UDP port number are described in the SIP message, the above problem appears when performing VoIP (Voice over IP) communication by SIP. Therefore, conventionally, a technique for converting an address described in a TCP payload or a UDP payload has been proposed.
[0005]
However, since the address conversion process of the upper layer protocol is complicated, there is a problem that it is difficult to improve the throughput in the conventional network connection device. Therefore, a system has been developed in which an address conversion of an IP header / UDP header is processed by an inter-network connecting device, and a conversion of an address in an SIP message is requested to a separately provided signal processing device. In this system, whether or not a packet is a SIP message related packet is distinguished by determining whether or not a specific address / port number is used (see Non-Patent Document 1).
[0006]
[Non-patent document 1]
Kazuhito Hayashi and four others, "A Study on Management Method of Address Translation Entry in SIP Application Level Gateway (SIP-ALG)", IEICE, IEICE, December 2002, NS2002-188, PS2002. -62, p. 25-28
[0007]
[Problems to be solved by the invention]
However, such a conventional network connection has the following problems.
[0008]
For example, when performing VoIP communication by SIP, a message that does not pass through the SIP server is not sent to the signal processing device. At first, consider a case where a message exchange between terminal A and SIP server and terminal B is exchanged, and a message exchange between terminal A and terminal B is switched halfway. In this case, the port numbers used in the communication between the terminal A and the terminal B are dynamically determined in order to notify each other at the time of communication via the SIP server.
[0009]
Here, before the communication path is switched, if the SIP server communicates with a specific port number, a packet whose port number is the originating port number or the destination port number may be sent to the signal processing device. However, after the communication path is switched, it is not expected to use the specific port number, so the packet is not sent to the signal processing device, and the address conversion in the upper layer protocol cannot be performed.
[0010]
The present invention has been made in view of the above circumstances, and an object of the present invention is to enable a network connection device and a signal processing device to cooperate with each other even when address information is dynamically determined during communication. An object of the present invention is to provide a method and a system for relaying packets between networks that can perform relaying.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an inter-network connecting device stores predetermined processing condition information for determining whether a processing request is required for a signal processing device in a storage device, If the packet received from the other packet network and satisfies the processing conditions stored in the storage device, a request for processing the packet is transmitted to the signal processing device, and the signal processing device And performs a predetermined process on the packet related to the processing request from the server, transmits a registration request message including at least address information to the network connection device, and the network connection device is included in the registration request message received from the signal processing device. The address information is stored in the storage device, and the packet is relayed based on the address information. Characterized by adding a processing condition information in the storage device in a predetermined condition based on the received registration request message.
[0012]
According to the present invention, a processing condition of which packet is to be processed by the signal processing device is added according to the content of the registration request message from the signal processing device that performs processing on the packet. Even when the address information is determined in a specific manner, the packet can be relayed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
A method and system for relaying packets between networks according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a network configuration diagram in the present embodiment of the present invention.
[0014]
In the following description, the address indicates a pair of an IP address and a UDP port number for a UDP packet, a pair of an IP address and a TCP port number for a TCP packet, and an IP address for other IP packets. I do.
[0015]
As shown in FIG. 1, the packet relay system includes a first packet network 10 to which a plurality of terminals 11-1 to 11-n are connected, and a first packet network to which a plurality of terminals 21-1 to 21-m are connected. An inter-network connection device 30 that connects the two packet networks 20 to each other, and a signal processing device 40 that cooperates with the inter-network connection device 30 to perform predetermined signal processing described later.
[0016]
In the present embodiment, the network connection device 30 and the signal processing device 40 cooperate to perform packet address conversion. That is, the network connection device 30 performs address conversion on the IP header and the TCP or UDP header of the packet, while the signal processing device 40 performs address conversion on the address embedded in a message of a higher protocol than TCP or UDP. In this embodiment, SIP will be described as such a higher-level protocol. Specifically, it is assumed that the terminal 11 in the first packet network 10 performs VoIP communication with the terminal 21 in the second packet network 20, and the call control of the VoIP communication is performed in the second packet network 20. Is performed by the SIP server 50 installed in the server.
[0017]
As shown in FIG. 2, the network connection device 30 includes a packet relay unit 31 that relays a packet received from one packet network to another packet, and an address conversion unit that converts the address of the relayed packet as necessary. 32, a conversion table 33 used for address conversion in the address conversion unit 32, and a condition information table 34 storing condition information for determining whether to request the signal processing device 40 to perform the address conversion. I have. In the present embodiment, the address conversion unit 32 converts the incoming / outgoing address of the first packet network 10 into an address that can be used on the second packet network 20 side. It uses technology.
[0018]
When the received packet matches any of the conditions stored in the condition information table 34, the packet relay unit 31 requests the signal processing device 40 to perform an address conversion process of the upper-level protocol message, and The address conversion unit 32 further performs address conversion on the converted packet received from the device 40, and then relays the packet. The packet to be processed by the signal processing device 40 is encapsulated and exchanged between the packet relay unit 31 and the signal processing device 40. On the other hand, if the received packet does not match any of the conditions stored in the condition information table 34, the address conversion is performed by the address conversion unit 32 without requesting the signal processing device 40 to perform the address conversion. And then relay the packet.
[0019]
In addition, when the packet relay unit 31 receives a registration request message described later from the signal processing device 40 and further includes an entry registration request to the condition information table 34 in the registration request message, The condition information on the address described in the registration request message is added to the condition information table 34.
[0020]
FIG. 3 shows an example of the condition information table 34. In the present embodiment, as shown in FIG. 3, the entry of the condition information table 34 is a set of a protocol type and an IP address and a port number of the first packet network 10 (in FIG. 3, the “first packet network side”). Is described as "inside" .- A set of an IP address and a port number on the second packet network 20 side (in FIG. 3, "the second packet network side" is described as "outside"). Have been. The condition information table 34 stores an entry relating to preset initial condition information and an entry added thereafter.
[0021]
The entry according to the initial condition matches the first packet in a series of packets to be converted by the signal processing device 40. In other words, the signal processing unit 40 starts signal processing of a series of packets triggered by a packet that matches the entry of the initial condition. In the present embodiment, since a packet relating to SIP communication is relayed, the initial condition is "a packet whose destination port number is a predetermined port number used in SIP".
[0022]
The address translator 32 translates the address of a packet to be relayed using the IP masquerade technique. Specifically, based on the entry in the conversion table 33, the conversion of the set of the IP address of the IP header and the port number of the UDP or TCP header is performed. The entry of the conversion table 33 is provided when there is an entry registration request from the signal processing device 40, or when communication is started under a predetermined condition even when there is no entry registration request from the signal processing device 40, A new address is issued, and this is registered as an entry. Here, when an address is issued based on an entry registration request from the signal processing device 40, the address information is notified to the signal processing device 40. FIG. 4 shows an example of the conversion table 33. As shown in FIG. 4, the entry of the conversion table 33 is a set of a protocol type and an IP address and a port number on the first packet network 10 side (in FIG. 4, “first packet network side” is described as “inside”). It is composed of a set of an IP address and a port number of the second packet network 20 (“the second packet network side” is described as “outside” in FIG. 4).
[0023]
The signal processing device 40 decapsulates the encapsulated packet received from the network connection device 30, converts the address included in a message of a higher protocol than TCP / UDP of the packet, encapsulates the converted packet, and encapsulates the converted packet. Return to connection device 30. At the time of this address conversion, first, an address is sent out to the network connection device 30 so as to issue an address for the address before the conversion and register the entry in the conversion table 33. Then, address conversion is performed using the payout address notified from the network connection device 30.
[0024]
The above-mentioned registration request message is added with a processing condition flag item indicating whether or not the packet matching the entry is to be processed by the signal processing device 40. The signal processing device 40 turns on the processing condition flag if it is to be processed by itself, and turns off the processing condition flag if it is not to be processed by the signal processing device 40. Whether or not to be processed by the signal processing device 40 is determined based on the contents of a message of a higher-level protocol based on the TCP / UDP of the packet. For example, in the case of SIP, the processing condition flag is turned on for a packet relating to the first SIP signaling in a series of flows from calling, voice communication, and termination of a call, and the processing condition flag is turned off for subsequent packets. do it. The determination as to whether or not it is the first SIP signaling may be performed by analyzing the SIP message (for example, whether or not it is “INVITE”).
[0025]
Next, the operation of the network connection device 30 will be described with reference to the flowchart of FIG.
[0026]
Upon receiving a packet from the first packet network 10 or the second packet network 20, the internetwork connection device 30 first determines whether the packet is registered in the condition information table 34 (step S1). If it is registered, it requests the signal processing device 40 to process the packet (step S2).
[0027]
Next, when there is a registration request message from the signal processing device 40 (step S3), a new address is paid out, and the address and the address information included in the registration request message are registered in the conversion table 33 (step S4). The issued address is notified to the signal processing device 40 (step S5). Next, when the processing condition flag included in the registration request message is on (step S6), the processing condition is entry-registered in the condition information table 34 for the address information included in the registration request message (step S7). Thereafter, the processed packet is received from the signal processing device 40 (step S8), and the packet is subjected to an address translation process based on the translation table 33 (step S9). Then, the packet after the address conversion is relayed (step S10).
[0028]
Next, the operation of the signal processing device 40 will be described with reference to the flowchart in FIG.
[0029]
When receiving the encapsulated packet from the network connection device 30, the signal processing device 40 first decapsulates the packet and then describes the packet in a higher-level protocol than TCP / UDP of the packet (that is, the packet is described in the payload). Address information is extracted (step S11). Next, it is determined about a predetermined condition (for example, whether or not this packet is the first packet of a series of communications) (step S12). The one with the flag turned on is transmitted to the inter-network connection device 30 (step S13). If the condition is not satisfied, a registration request message with the processing condition flag turned off is transmitted to the inter-network connection device 30 (step S14). . Then, in step S5, the delivery address from the inter-network connecting device 30 is received (step S15), and a conversion process for rewriting address information described in the payload of the packet is performed based on the delivery address (step S16). Next, the converted packet is encapsulated and returned to the internetwork connection device 30 (step S17).
[0030]
Next, a flow when the terminal 11 in the first packet network 10 performs VoIP communication with the terminal 21 in the second packet network 20 using the relay system of the present embodiment will be described with reference to FIG. . FIG. 7 is a diagram for explaining a series of flows in the VoIP communication.
[0031]
Since SIP is used as the call control protocol in the present embodiment, as shown in FIG. 7, VoIP communication is realized by a SIP signaling flow 61 that is a flow related to call control and a voice flow 62 that is related to voice communication. Is done. The SIP signaling flow 61 is a communication between the terminal 11 and the server 50 and a communication between the server 50 and the terminal 21, and the voice flow 62 is a communication between the terminal 11 and the terminal 21.
[0032]
A more specific procedure is as follows. That is, when the terminal 11 sends a connection request signal including the identifier of the terminal 21 to the server 50, the server 50 resolves the address of the terminal 21 from the identifier and sends a connection request signal to the terminal 211. The terminal 21 sends a connection response signal to the server 50, and the server 50 sends a connection response signal to the terminal 11. Since the connection request signal includes the voice packet receiving address of the terminal 11 and the connection response signal includes the voice packet receiving address of the terminal 21, the terminals 11 and 21 can send voice packets to each other. .
[0033]
Next, the flow when the terminal 11 performs VoIP communication with the terminal 21 will be described in more detail with reference to FIG. FIG. 8 is a sequence chart illustrating the flow of the VoIP communication. In FIG. 8, among the circle symbols attached to the start point and the end point of the arrow indicating the flow of the packet, the black circle symbol indicates that the packet is the start point or the end point, and the white circle indicates the start point or the end point of the packet. It means that there is no.
[0034]
As shown in FIG. 8, when the calling terminal 11 transmits a connection request to a predetermined port of the SIP server 50, the network connection device 30 encapsulates the packet and sends it to the signal processing device 40.
[0035]
The signal processing device 40 sends a registration request message in which the voice packet reception address and the SIP signaling reception address of the terminal 11 described in the packet are described to the internetwork connection device 30. At this time, since the packet is the first packet in a series of flows, the processing condition flag corresponding to the SIP signaling reception address is turned on, and the processing condition flag corresponding to the voice packet reception address is turned off.
[0036]
Upon receiving the registration request message, the network connection device 30 pays out the address held by the network 20 on the terminal 21 side, and stores the paid out address in the conversion table 33 in association with the address described in the registration request message. Note that the registration of the conversion table 33 here is for both voice flow and SIP signaling. Since the condition processing flag is turned on for the registration request related to the SIP signaling reception address of the registration request message, the registration request message is stored in the condition information table 34 in association with the issued address and the SIP signaling reception address. On the other hand, the paid out address is described in the response message and sent to the signal processing device 40.
[0037]
When the signal processing device 40 receives the response message, the signal processing device 40 rewrites the address of the terminal 11 described in the original SIP signaling packet to the address described in the response message, further encapsulates the address, and encapsulates the address. Send to
[0038]
Upon receiving the encapsulated message from the signal processing device 40, the network connection device 30 removes the encapsulation, performs address conversion according to the conversion table 33, and sends the address to the network 20 of the terminal 21.
[0039]
For the second and subsequent messages, there is no need to make an entry registration request for address information equal to the first message.
[0040]
If the second and subsequent messages do not pass through the server, the network connection device 30 detects that the address described in the header is registered in the condition information table 34 as an entry, and , A predetermined address translation is applied, the packet is encapsulated and sent to the signal processing device 40.
[0041]
When the voice packet flows, the network connection device 30 performs the address conversion according to the conversion table 33 because the address described in the header is not entered in the condition information table 34, and Send to network 20.
[0042]
As described above, according to the present invention, according to the content of the registration request message from the signal processing device 40 that performs processing on the packet, the processing condition of which packet is to be processed by the signal processing device 40 is set in the condition information table Even if the address information is dynamically determined during communication, which is added to the packet 34, the packet can be relayed.
[0043]
Although the embodiment of the present invention has been described in detail, the present invention is not limited to this. For example, in the above-described embodiment, the address conversion unit 32 converts a set of an IP address and a TCP / UDP port number. However, the present invention can be applied to a case where only the IP address of the IP header is converted. .
[0044]
Further, in the above embodiment, the conversion table 33 for storing the address conversion rules and the condition information table 34 for storing the processing conditions for requesting the signal processing device 40 to perform processing are provided separately. As shown in FIG. 4, since the management items are similar to each other, they may be implemented in one table.
[0045]
Furthermore, in the above-described embodiment, SIP has been exemplified as an upper protocol in which an IP address and a TCP / UDP port number are embedded, but the present invention can be implemented with other protocols. For example, H.264 in which address information is embedded in a protocol. H.323 and FTP.
[0046]
Furthermore, in the above-described embodiment, the address conversion is exemplified as the processing content in the signal processing device 40, but the present invention can be implemented even when performing other processing. For example, there is a case where packet filtering is performed in the network connection device 30. Specifically, the signal processing device 40 analyzes the address described in the message of the upper protocol and notifies the signal to the inter-network connecting device 30. The inter-network connecting device performs packet filtering setting based on the notified information. One that changes dynamically.
[0047]
【The invention's effect】
As described in detail above, according to the present invention, not only a message between a terminal and a server is processed by a signal processing device, but also a message between terminals that is not preset is processed by a signal processing device. . As a result, for example, SIP address conversion can be performed by an external device.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a network configuration. FIG. 2 is a diagram illustrating a configuration of a packet relay system between networks. FIG. 3 is a diagram illustrating an example of a conversion table. FIG. 4 is a diagram illustrating an example of a condition information table. FIG. 6 is a flowchart for explaining the operation of the signal processing device. FIG. 7 is a diagram for explaining a series of flows in the VoIP communication. FIG. 8 is a sequence chart for explaining the flow of the VoIP communication. [Explanation of symbols]
10, 20 packet network, 11, 21 terminal, 30 network connection device, 31 packet relay unit, 32 address conversion unit, 33 conversion table, 34 condition information table, 40 signal processing device, 41 ... Address conversion unit, 50 ... SIP server

Claims (5)

A method in which an inter-network connecting device that interconnects a plurality of packet networks relays a packet in cooperation with a signal processing device,
The network connecting device stores predetermined processing condition information for determining whether a processing request to the signal processing device is necessary in a storage device, and the packet received from one packet network to another packet network is stored in the storage device. If the processing condition stored in the storage device is satisfied, a request for processing the packet is transmitted to the signal processing device,
The signal processing device performs a predetermined process on a packet related to a processing request from the inter-network relay device, transmits a registration request message including at least address information to the inter-network connection device,
The network connection device stores the address information included in the registration request message received from the signal processing device in the storage device, performs a relay process of a packet based on the address information, and performs the registration request message received from the signal processing device. A method of relaying packets between networks, wherein processing condition information is added to the storage device on a predetermined condition based on the condition. The registration request message includes flag information indicating whether to add the processing condition information to the processing condition information, and the network connection apparatus determines whether to add the processing condition information based on the flag information included in the registration request message received from the signal processing device. 2. The method according to claim 1, wherein the packet is relayed. The predetermined process in the signal processing device includes an address translation process, and the network connection device performs an address translation process based on address information included in a registration request message received from the signal processing device at the time of a packet relay process. 3. The method according to claim 1, wherein the packet is relayed between networks. The packet network is composed of an IP (Internet Protocol) packet network, and the address is a pair of an IP address and a UDP port number for a UDP (User Datagram Protocol) / IP packet, and a TCP (Transmission Control Protocol) / IP packet IP address. 4. The method according to claim 1, wherein a pair of a TCP port number and a TCP port number is an IP address for another IP packet. In a system in which an inter-network connecting device that interconnects a plurality of packet networks relays a packet in cooperation with a signal processing device,
The network connection device includes a storage device that stores predetermined processing condition information for determining whether a processing request to the signal processing device is necessary, and a storage device that stores a packet received from one packet network to another packet network. Means for transmitting a processing request for the packet to the signal processing device when the processing condition stored in the storage device is satisfied, and storing the address information included in the registration request message received from the signal processing device in the storage device. Means for performing packet relay processing based on the address information, and means for adding processing condition information to the storage device under predetermined conditions based on a registration request message received from the signal processing device,
The signal processing device includes means for performing predetermined processing on a packet related to a processing request from the inter-network relay device and transmitting a registration request message including at least address information to the inter-network connection device. Packet relay system.

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