JPH1084347A - Address resolution method and address converter for lan emulation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an address resolution method for the LAN emulation in which number of packets to be sent is reduced in the case of execution of an address solution protocol. SOLUTION: An IP/MAC-ARP in a terminal equipment 1 started to acquire a medium access control(MAC) address of a destination terminal equipment 3 generates a predetermined dummy MAC address and processes the dummy MAC address by regarding it as a MAC address of the terminal equipment replied from the terminal equipment 3. Furthermore, an IP/ATM-ARP client in the terminal equipment 1 started to acquire the ATM address of the destination terminal equipment 3 sends an ATM address acquisition request including the destination IP of the terminal equipment 3 sends the IP/ATM-ARP server of a terminal equipment 2, and the IP/ATM-ARP server of a terminal equipment 2 retrieves the ATM address acquisition request corresponding to the destination IP address included in the ATM address acquisition request and replies it to the IP/ATM-ARP client in the terminal equipment 1. Thus, the terminal equipment 1 acquires the destination ATM address of the terminal equipment 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an address resolution method in LAN emulation on an ATM network and an address translation device applied to an ATM network using the address resolution method.

[0002]

2. Description of the Related Art In an ATM network, high-layer protocols of a LAN (Local Area Network) already constructed widely in a company or the like are accommodated without change by using LAN emulation.

An address resolution protocol (ARP) is one of the high-layer protocols of the existing LAN.
ution Protocol). For example, as a data link protocol, CSMA / CD (Carrier Sense Multiple Access
th Collision Detection) and LAN using IP (Internet Protocol) as the network layer protocol
In MAC, a MAC (Media Access Cd) which is a physical address for identifying a terminal connected on the same coaxial cable
Ontrol) addresses are used, and IP addresses, which are logical addresses, are used to identify terminals connected on different coaxial cables. Therefore, each terminal has a MAC address and an IP address.

[0004] However, since each terminal manages the IP address of the other terminal but does not manage the MAC address, it is necessary to acquire the MAC address in order to communicate with the other terminal. Therefore, for example, the terminal 1
When acquiring the MAC address, the terminal 1 transmits an IP address acquisition request including the IP address of the terminal 2 to all terminals. Each terminal sees the IP address, and if it is its own IP address, transmits a reply including its own MAC address to the terminal 1. The terminal 1 has acquired the MAC address of the terminal 2 by such a series of procedures (IP / MAC-ARP).

When an existing LAN is realized on an ATM network, it is necessary that the above-mentioned IP / MAC-ARP can be accommodated as it is, and at the same time, it is an address on the ATM network in addition to the IP address and the MAC address. ATM address required. The mechanism for obtaining the ATM address usually employs a client / server system in accordance with the standard of the ATM Forum, and includes a client and a server. For example, when the client of the terminal 1 acquires the ATM address of the terminal 3, the client of the terminal 1 transmits an ATM address acquisition request including the MAC address of the terminal 3 to the server of the terminal 2. The server of the terminal 2
MA of terminal 3 using MAC address / ATM address correspondence table
Search for ATM address corresponding to C address
The reply including the ATM address is transmitted to the client of the terminal 1. Through such a series of procedures (MAC / ATM-ARP), the client of the terminal 1 has acquired the ATM address of the terminal 3.

[0006]

However, in the conventional LAN emulation described above, it is necessary to activate two address resolution protocols, IP / MAC-ARP and MAC / ATM-ARP, in order to obtain an ATM address. there were. As a result, the number of packets sent to the ATM network during the execution of the address resolution protocol increases compared to the existing LAN where only IP / MAC ARP needs to be activated to obtain the MAC address. As a result, there is a disadvantage that the probability of causing packet congestion increases.

[0007] The present invention solves the above-mentioned drawbacks of the prior art, and an LA on an ATM network in which the number of packets transmitted to the network during execution of an address resolution protocol is small.
It aims to provide an address resolution method in N emulation.

[0008]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, an address resolution method according to the present invention provides a LAN which emulates a LAN application on an ATM network.
Address resolution method in emulation,
In this method, a terminal generates a MAC address acquisition request including a destination IP address and a dummy answer including a predetermined dummy MAC address, and the terminal corresponding to the IP address responds to the MAC address acquisition request with the dummy answer. The terminal sends the ATM address acquisition request including the destination IP address to the server, assuming that the answer includes the MAC address sent by the terminal, and uses the dummy MAC address extracted from the dummy answer as the destination MAC address. The ATM address corresponding to the IP address included in the ATM address acquisition request is searched for using the IP address / ATM address
An answer including the M address is transmitted to the terminal, and the ATM address acquired by the terminal extracting from the answer is used as a destination ATM address.

[0009] The address translation device according to the present invention comprises:
An address translation device in an ATM network in which a data packet to which a predetermined dummy MAC address is added as a destination MAC address by applying LAN emulation is transmitted. This device inputs a dummy MAC address of an input data packet. The data packet is converted into a MAC address corresponding to a destination ATM address of the data packet.

In this case, the MA corresponding to the destination ATM address
For the C address, the address translation device sends a MAC address acquisition request including the destination ATM address to the server, and the server uses the ATM address / MAC address correspondence table to check the MAC address corresponding to the ATM address included in the MAC address acquisition request.
It is preferable that the address is retrieved, a response including the MAC address is transmitted to the address translator, and the MAC address acquired by the address translator extracting from the response is used.

The MAC address corresponding to the destination ATM address is preferably a MAC address searched using an ATM address / MAC address correspondence table provided in the address translation device in advance.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an address resolution method and an address translation device in LAN emulation on an ATM network according to the present invention will be described in detail with reference to the accompanying drawings.

First, an embodiment of an address resolution method according to the present invention will be described. Originally, in ATM-LAN routing, matching between IP address and ATM address is sufficient, and MAC address is not required. However, a MAC address is required to use IP / MAC-ARP in the existing LAN as it is. The address resolution method of this embodiment eliminates packets sent to the ATM network by adopting a dummy MAC address in this IP / MAC ARP, and executes the ATM network when executing the address resolution protocol for obtaining the MAC address and the ATM address. To reduce the number of packets sent to the network, thereby reducing the probability of causing packet congestion.

FIG. 1 is a block diagram showing an embodiment of an ATM network to which an address resolution method according to the present invention is applied. FIG. 1A shows the operation of IP / MAC-ARP, and FIG. FIG. 9 is a diagram for explaining an operation of IP / ATM-ARP described later. FIG.
In (a), terminals 1 to 3 are apparently operating as LAN terminals by LAN emulation, each of which has an IP / MAC-ARP, and a cable concentrator (ATM HUB) by a cable. 4 is connected. The concentrator 4 has a plurality of ports, and relays a data packet from a terminal connected to a certain port to each terminal connected to another port. In this embodiment, three terminals are connected by one concentrator for convenience of explanation.
An ATM network is taken as an example, but the present invention is not limited to this configuration.

Further, in the present embodiment, the IP address
Address resolution protocol (IP /
ATM-ARP) shall have a client / server configuration in accordance with the standards of the ATM Forum.
IP / ATM-ARP client and IP / ATM-ARP server exist. In the present embodiment, as shown in FIG. 1 (b), the terminal 1 and the terminal 2 have IP / ATM-ARP clients, and the terminal 3 has an IP / ATM-ARP client.
It is assumed that each TM-ARP server is located.

Next, the operation of this embodiment will be described.

For example, when the terminal 1 communicates with the terminal 3 by LAN emulation, as described above, the terminal 1
Needs to obtain the MAC address and ATM address of the terminal 3. Therefore, the terminal 1 first sets the MAC of the terminal 3
As shown in Fig. 1 (a), IP / M
Start AC-ARP. The activated IP / MAC-ARP generates a MAC address acquisition request including the IP address of the terminal 3 to be transmitted to each terminal, and generates a predetermined dummy MA.
Generate a dummy answer containing the C address.

Then, the IP / MAC-ARP does not actually transmit the generated MAC address acquisition request to each terminal, but transmits the generated dummy answer to the terminal 3 when the MAC address acquisition request is transmitted to each terminal. Is assumed to include the MAC address of the terminal 3 to be transmitted from the terminal, and a dummy MAC address is extracted from the dummy answer, and the dummy MAC address is extracted.
Processing is performed assuming that the C address is the MAC address of the terminal 3.

As a result, the terminal 1 activates the IP / MAC-ARP and acquires the MAC address (a dummy MAC address) of the terminal 3 as in the case of the existing LAN. It does not send out packets on the network and does not receive packets. Therefore, the probability of occurrence of packet congestion in the ATM network can be reduced as compared with the conventional case. Further, as described above, since the MAC address is not required for the ATM-LAN routing, using the dummy MAC address in place of the MAC address of the destination terminal 3 does not cause any problem in the present embodiment. .

Next, the terminal 1 activates an IP / ATM-ARP client as shown in FIG. 1 (b) to obtain the ATM address of the terminal 3. The activated IP / ATM-ARP client issues an ATM address acquisition request including the IP address of the terminal 3.
(request) to the IP / ATM-ARP server of the terminal 2. When the server of the terminal 2 receives the ATM address acquisition request from the terminal 1 transmitted through the line concentrator 4, the ATM
The ATM address corresponding to the IP address of the terminal 3 included in the address acquisition request is searched for each terminal using the IP address / ATM address correspondence table in which the ATM address corresponding to the IP address is recorded.

Then, the server of the terminal 2 transmits a reply including the ATM address of the terminal 3 obtained by the search to the client of the terminal 1. The client of the terminal 1 receives this response and acquires the ATM address of the terminal 3. Next, the terminal 1 establishes a virtual channel with the terminal 3 based on the acquired ATM address of the terminal 3 and performs communication.

As described above, according to the present embodiment, two ARPs, IP / MAC-ARP and IP / ATM-ARP, are activated in the same manner as in the prior art. Since a dummy MAC address generated by itself is used as a destination MAC address, neither a packet is transmitted nor a packet is received to acquire a MAC address. Therefore, IP / M
When executing AC-ARP and IP / ATM-ARP, the number of packets sent to the ATM network is reduced compared to the conventional case.
The probability of causing packet congestion is reduced.

Next, an address translation device according to the present invention will be described. FIG. 2 shows the use of this address translator.
FIG. 2 is a configuration diagram illustrating an example of an ATM network. In this embodiment, a MAC is provided to a concentrator 4 to which terminals 1 to 3 shown in FIG.
The bridge 6 is connected to expand the network. Here, the MAC address translator 5 receives the input ATM
Assembling the cell into a data packet, converting the MAC address of the data packet to a predetermined destination MAC address,
After that, it is again decomposed into ATM cells and output. The MAC bridge 6 interconnects the ATM networks and controls whether the data packet is passed or discarded by checking the MAC address of the received data packet.

A data packet to which a dummy MAC address is added is transmitted to the ATM network shown in FIG. 2, as in the embodiment shown in FIG. Therefore, MA
In order for the C bridge 6 to operate normally, the destination added to the data packet input to the MAC bridge 6
The MAC address needs to be replaced with the original destination MAC address instead of the dummy MAC address. Therefore, in the present embodiment, the MAC address translator 5 is provided, and the dummy data packet transmitted to the MAC bridge 6 is provided.
It converts the MAC address to the original destination MAC address.

In this embodiment, the MAC / ATM-ARP for acquiring the MAC address has a client / server configuration.
There is an ATM-ARP server. The location where the client and server are present is not particularly limited, but in the present embodiment, as shown in FIG. 2, the MAC / ATM-ARP client is used for the MAC address translator 5 and the MAC / ATM-ARP server is used for It is placed in each of the concentrators 4.

Next, the operation of this embodiment will be described.

First, when terminals communicate with each other in the ATM network shown in FIG. 2, for example, IP / MAC-ARP and IP / ATM when terminals 1 and 3 communicate with each other.
The operation of -ARP is the same as that of the embodiment shown in FIG.
Next, when communicating with another network, for example, when the terminal 1 communicates with a terminal 4 (not shown) in another network connected to the MAC bridge 6, a data packet transmitted from the terminal 1 to the terminal 4 , The MAC address conversion device 5 converts the MAC address.

More specifically, the MAC address translator 5 transmits the address transmitted from the terminal 1 to the terminal 4 through the concentrator 4.
Receives ATM cells and once assembles them into data packets. Then, a MAC / ATM-ARP client is started to obtain the destination MAC address of the terminal 4. The activated MAC / ATM-ARP client transmits a MAC address acquisition request (request) including the ATM address of the terminal 4 (the ATM address of the received ATM cell) to the server of the hub 4. Upon receiving the MAC address acquisition request, the server of the hub 4 receives the MAC address corresponding to the ATM address of the terminal 4 included in the request and replaces the MAC address / ATM in which the MAC address corresponding to the ATM address is recorded for each terminal. Search using the address correspondence table. Then, a reply including the searched MAC address is transmitted to the client of the MAC address translator 5.

The client of the MAC address translator 5 receives this response and knows the destination MAC address of the terminal 4. The MAC address translator 5 replaces the dummy MAC address of the previously assembled data packet with the destination MAC address of the terminal 4 obtained from the server 4. Next, the data packet is decomposed again into ATM cells, and each ATM cell is transmitted to the MAC bridge 6. Upon receiving the data packet from the MAC address translator 5, the MAC bridge 6 checks whether the MAC address is a predetermined address. For example, a data packet to which the MAC address of the terminal 4 is added passes Let it.

As described above, according to the present embodiment, a MAC address conversion device for converting a dummy MAC address into a destination MAC address is provided, and therefore, as shown in the embodiment shown in FIG. MAC bridges can also be used in ATM networks where the added data packets are sent.

When the address is translated by the MAC address translator, the packet based on the MAC / ATM ARP is sent to the ATM network as described above. But the existing LA
In N, generally, the number of MAC
Since the number of bridges is small, the number of packets reduced by assigning a dummy MAC address during IP / MAC-ARP operation of the terminal is much smaller than the number of packets transmitted by MAC / ATM-ARP. It is thought that there are many. Therefore, even in an ATM network in which a MAC bridge is installed, applying the address resolution method according to the present invention is effective in reducing the number of packets and the probability of occurrence of congestion.

Note that the MAC / ATM-AR
If you put P client and MAC / ATM-ARP server, MAC
The load on the address translator itself increases, but MAC / ATM
-ARP eliminates packets sent to the ATM network, thereby reducing the probability of packet congestion.

[0033]

As described above, according to the present invention, the IP / MAC-ARP is used for obtaining the destination MAC address and the destination ATM address in LAN emulation on the ATM network.
IP / ATM-ARP and IP / ATM-ARP, but the IP / MAC-ARP returns the generated dummy MAC address to itself and does not actually send the packet over the ATM network. -The number of packets can be reduced and the probability of packet congestion can be reduced as compared with the conventional address resolution protocol that actually sends packets over an ATM network when ARP is executed.

According to the above-mentioned IP / MAC-ARP and IP / ATM-ARP, a data packet to which a dummy MAC is added as a destination MAC address is transmitted to the ATM network. A MAC bridge can be used by providing an address translator for translating addresses. In other words, even in an ATM network in which a MAC bridge is installed, by using an address translation device, the address resolution method according to the present invention using a dummy MAC address in IP / MAC-ARP is applied, and the Decrease the number,
The probability of causing packet congestion can be reduced.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of an ATM network to which an address resolution method in LAN emulation according to the present invention is applied.

FIG. 2 shows an ATM to which an address translation device according to the present invention is applied.
FIG. 2 is a configuration diagram illustrating an example of a network.

[Explanation of symbols]

 1, 2, 3 terminals 4 ATM concentrator 5 MAC address converter 6 MAC bridge

Claims (4)

[Claims] 1. An address resolution method in LAN emulation for emulating a LAN application on an ATM network, the method comprising: a terminal acquiring a MAC address including a destination IP address; and a predetermined dummy MAC address. And a terminal that corresponds to the IP address transmits the dummy response in response to the MAC address acquisition request.
Considering the answer including the C address, the dummy MAC address extracted from the dummy answer is used as the destination MAC address, the terminal transmits an ATM address acquisition request including the destination IP address to the server, and the server transmits the ATM address. Using the ATM address correspondence table, search for the ATM address corresponding to the IP address included in the ATM address acquisition request, and
An address resolution method in LAN emulation, wherein an answer including an M address is transmitted to the terminal, and the ATM address obtained by the terminal extracting from the answer is used as a destination ATM address. 2. The destination by applying LAN emulation
An address translation device in an ATM network to which a data packet to which a predetermined dummy MAC address is added as a MAC address is transmitted, wherein the device converts the dummy MAC address of an input data packet to a destination of the input data packet. An address translation device for translating a MAC address corresponding to an ATM address. 3. The address translation device according to claim 2, wherein the MAC address corresponding to the destination ATM address is transmitted to the server by the address translation device transmitting a MAC address acquisition request including the destination ATM address. But
MAC corresponding to the ATM address included in the MAC address acquisition request using the ATM address / MAC address correspondence table
An address translator characterized by being a MAC address obtained by retrieving an address, transmitting a response including the MAC address to the address translator, and extracting the address from the response by the address translator. 4. The address translation device according to claim 2, wherein the MAC address corresponding to the destination ATM address is a MAC address retrieved using an ATM address / MAC address correspondence table provided in advance in the address translation device. An address translation device, characterized in that: