JPH10322382A - Network repeating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To convert the addresses of multiple terminals in a network only by means of preparing few conversion addresses by permitting a network repeating device connected to the different type of LAN to allocate a high-order identifier in data and translating the address. SOLUTION: A routing control part 11 operates a routing packet from a local side network A and an address conversion part 12 executes address conversion. The address translation part 12 coverts an IP address into a virtual address allocated from the address allocated to a remote side network B. An address translation table 13 is referred to and the existence of an entry having the same virtual address and port ID as the packet is retrieved. When it exists, the port ID of the packet is rewritten into the virtual port ID of the address translation table 13 so as to output it. When it does not exist, the virtual address is added to the address translation table 13 and port ID is rewritten and outputted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a relay device between networks, and more particularly, to a relay device between different networks.

[0002]

2. Description of the Related Art In a network, various computers are connected via a LAN using a coaxial cable, an optical fiber cable or the like as a common transmission line, and countless communications are simultaneously performed between the computers. Relay devices between these network terminals are classified as follows according to what level of protocol is executed.

FIG. 4 shows a relay device between terminals of a network and the levels of their protocols. FIG. 5 shows the layers of the data communication protocol. (A) is the OSI protocol, and (B) is the TCP / IP protocol. For example, in the case of using IP over Ethernet, the repeater performs bit-level relay and does not recognize it as data (a set of bits).

[0004] The upper bridge relays a frame which is a data unit on the transmission path. Based on the MAC address (Ethernet address) stored in the header of the MAC (Media Access Control) frame which is data of the data link layer, it is determined whether or not to execute the relay. It doesn't care about the protocol above the network layer. The router performs IP header processing based on the IP protocol and performs relaying at the network layer level, and can perform relaying even if the data link layer and the like, such as the MAC system and the line interface, are different. Since router route control is performed on a network basis, M
AC address is not relevant.

[0005] For this reason, it is used for a wide range of purposes such as a trunk LAN node device, heterogeneous LAN connection, wide area network connection, and dual path. By the way, in the relay between different networks, that is, in the heterogeneous LAN connection, the source address is usually not prepared in the destination network. For example, when a LAN is constructed with a private address, communication is not possible even if connected on a global network because there is no routing information. Therefore, when transmitting to a partner network by a relay device between networks, that is, a router, the address conversion table is converted into a global address in the router and converted into a source address that can be remoted from a terminal of the partner network and transmitted. I do. FIG. 6 shows an example of address conversion, in which a plurality of addresses to be converted, for example, n addresses are prepared, and the addresses are sequentially assigned and converted. In FIG. 6, X1 to Xn are source addresses, and B1 to Xn.
Bn is a destination address. Source addresses X1 to Xn
Is not available on the receiving network,
The address is converted into an address A1 to An that can be remoted from the terminal of the partner network.

[0006]

In the above case, if all the n addresses prepared for the conversion are allocated, it becomes impossible to perform further address conversion.
When the number of addresses for translation is small, the number of address translations from one network to another network is limited. For example, in the extreme case, when only one address is prepared, the address is used for the address conversion of the packet from the router itself, and the address conversion service cannot be provided to the network terminal. In recent years, as networks have become larger,
There is also a problem that access between different networks is frequent, and therefore, a translation table for address translation becomes enormous. In addition, the above address conversion has a problem that two or more networks cannot be converted and relayed.

An object of the present invention is to solve the above problems and to provide a network relay device capable of performing address translation of a large number of terminals in a network by preparing only a small number of translated addresses. is there.

[0008]

The present invention has the following means to solve the above problems.

According to the first aspect of the present invention, when data is transmitted from a terminal of one network to a terminal of the other network, the address of the terminal of one network is converted to the address of the other network. A network relay device of a heterogeneous LAN connection, wherein the address is converted by assigning a higher-order identifier in the data.

According to a second aspect of the present invention, when the protocol of the network layer of one of the networks is IP, the network relay device assigns a port identifier of the transport layer as an upper identifier and performs conversion. .

According to a third aspect of the present invention, in the case where an application program of one network is OSI, an ID identifier of a transport layer is assigned as an upper identifier and converted.

According to the network relay device of the first aspect of the present invention, since the address is converted by assigning the upper identifier in the data, the address after the address conversion is
For example, even if it is one IP address, this one IP address
It can be added to the address as many as the upper protocol identifier has. As a result, it is possible to convert the number of network terminals having the higher-order protocol identifier by one IP address.

According to the second and third aspects of the present invention, the upper identifier assigned to the address after the address conversion is the upper identifier of the application program of the transmission source network.
Even if the response packet from the transmission destination is, for example, one IP address, the address reverse conversion can search the terminal of the transmission source network by the upper identifier.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the network relay device according to the present invention will be described below in more detail with reference to FIGS. FIG. 1 is a block diagram showing one embodiment of the network relay device of the present invention. In FIG.
Is a network relay device, 11 is a routing control unit,
12 is an address conversion unit, 13 is an address conversion table,
Reference numeral 14 denotes a virtual address virtual port / ID assigning unit, A is a local network, and B is a remote network.

A routing packet input from the local network A is subjected to a packet operation for routing by the routing control unit 11. The packet whose packet operation has been completed by the routing control unit 11 is subjected to address conversion by the address conversion unit 12.
In the present embodiment, the application program will be described using an example of the TCP / IP protocol. However, in the case of the OSI protocol, the description will be omitted by replacing the terms in parentheses (for example, the port with (ID)). .

FIG. 2 shows a packet format of the TCP / IP protocol. The address conversion unit 12 converts the IP address from the address assigned to the remote network B to one assigned virtual address. The translated virtual address is referred to the address translation table 13, and the same virtual address and UDP / T
A search is performed to determine whether an entry having a CP (ICMP) port (ID) exists. If the same entry exists, the UDP / TCP / ICMP port (ID) of the packet is set to the UDP / TCP of the address conversion table 13.
/ ICMP rewrite output to virtual port (ID). If the translated virtual address does not exist in the address translation table 13, the address translation table 1
3 is added, and based on the information, the UDP / TCP / ICMP port (ID) of the packet is rewritten and output.

The virtual address is assigned by the virtual address virtual port (ID) allocating unit 14 to the address conversion table 1.
When adding to 3, the virtual port (ID) of UDP / TCP / ICMP is assigned a unique value. The routing packet input from the remote side network B is searched by the address conversion unit 12 for the existence of the IP address of the packet and the virtual port (ID) of UDP / TCP / ICMP of the packet. As a result of the search, if there is no address translation table 13 having the same IP address and virtual port (ID), the packet is discarded and not output.

If there is one having the same IP address and port (ID) information, the IP address and the UDP / TC
The port (ID) of the P / ICMP is converted, the routing is performed by the routing control unit 11, and output to the local network B.

The address conversion will be described more specifically based on the address conversion table 13 shown in FIG. In the address conversion table 13 shown in FIG.
The P address and A1 are virtual IP addresses. In FIG. 3, the source IP address is one virtual IP address A
Converted to 1 and the source port (ID) identifiers 100 to n00
Is assigned, and the virtual port (I
Rewrite as D). Although the source IP address is converted into one virtual IP address A1 in FIG. 3, the number of virtual IP addresses is not limited to one, but may be a plurality of virtual IP addresses.
Obviously, the addresses may be aggregated.

[0020]

As described above, according to the network relay device of the first aspect of the present invention, since the address is converted by assigning the upper identifier in the data, the address after the address conversion is, for example, 1 Even one IP address can be added to this one IP address by the number of upper-layer protocol identifiers. As a result, it is possible to convert the number of network terminals having the higher-order protocol identifier by one IP address.

According to the network relay device of the present invention, the upper identifier assigned to the address after the address conversion is the upper identifier of the application program of the transmission source network.
Even if the response packet from the transmission destination is, for example, one IP address, the address reverse conversion can search the terminal of the transmission source network by the upper identifier.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of a network relay device of the present invention.

FIG. 2 shows T used in the network relay device of the present invention.
FIG. 3 is an explanatory diagram showing a packet format of a CP / IP protocol.

FIG. 3 is an explanatory diagram showing a specific example of an address conversion table used in the network relay device of the present invention.

FIG. 4 is an explanatory diagram showing a relay device between terminals of a network and a protocol level thereof;

FIG. 5 shows the layers of a data communication protocol,
(A) is an explanatory diagram of the OSI protocol, and (B) is an explanatory diagram of the TCP / IP protocol.

FIG. 6 is an explanatory diagram showing an example of an address translation table used in a conventional network relay device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Network relay device 11 Routing control unit 12 Address conversion unit 13 Address conversion table 14 Virtual address virtual port / ID A Local network B Remote network

Claims (3)

[Claims] 1. A heterogeneous LAN connection network relay device for converting an address of a terminal of one network into an address of another network when transmitting data from a terminal of one network to a terminal of the other network. The network relay device, wherein the conversion of the address is performed by assigning a higher-order identifier in the data. 2. The network relay device according to claim 1, wherein when a network layer protocol of one of the networks is IP, a port identifier of a transport layer is assigned and converted as an upper identifier. 3. The network relay device according to claim 1, wherein when the application program of one of the networks is OSI, an ID identifier of a transport layer is assigned and converted as an upper identifier.