JPH11298501A - Transmitter for resolving atm address - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a transmitter that resolves an ATM address in a system where inter-terminal communication is conducted by using a layer 3 address via an asynchronous transfer mode ATM switch network. SOLUTION: A switching HUB, e.g. 10-1, receives a layer 3 address and a layer 2 address of a terminal connecting to itself, registers them to a table, receives its ATM address and a layer 3 address of other terminal from other switching HUB, e.g. 10-2 and registers them to the table. While referring to the table based on the layer 3 address of a destination terminal received from the terminal connecting to itself an ATM address of the other corresponding switching HUB 10-2 is acquired and sends a cell to the destination via the other switching HUB 10-2. Furthermore, while referring to the table based on the layer 3 address of the destination terminal received from a terminal connecting to the other switching HUB 10-2 the layer 2 address of the terminal connecting to itself is acquired and sends the received data to the terminal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a network system for performing terminal-to-terminal communication through an ATM (Asynchronous Transfer Mode) switch network, and more particularly to a method for resolving an ATM address between a terminal device and an ATM switch network. And a transmission device that performs

[0002]

2. Description of the Related Art Existing LAN (Local Area N)
network and an ATM switch network, LAN emulation and IPover ATM
(IP over ATM). The LAN emulation method is a method of emulating an existing LAN such as Ethernet or Token Ring, and converting a MAC address on the existing LAN into an ATM address. Also IP
The over ATM method is a method for converting an IP address on an IP (Internet Protocol) network into an ATM address. The LAN emulation method is described in, for example, "Picture Time ATM Network Bible" (Ohm, P.111-P.115). Regarding the IPover ATM method, IE
TF (Internet Engineering T
RFC (Requests) created by ask Force
ts For Comments) 1577 and RFC
1755.

FIG. 18 is a diagram for explaining an address resolution method of the LAN emulation method. The ATM switch network includes LEC (LAN emulation client), LECS (LAN emulation configuration server), LES (LAN emulation server) and BUS (broadcast and
(Unknown server) are connected. LEC
S, LES, and BUS are server devices that provide an address resolution service. LEC has an existing LAN interface and ATM interface.
This is a device that acts as a bridge interposed between the switch network and the existing LAN together with the terminal device.

[0004] LEC-A which is an ATM end device is LE
The procedure for acquiring the CB ATM address is as follows. LEC-A is connected to LES A at initialization such as power-on.
A connection is established with the LECS managing the TM address, and the ATM address of the LES is acquired (). The LES manages a correspondence table (address management table) between the MAC address of the LEC and the ATM address. When the LEC-A receives the frame from the terminal, the LEC-A establishes a connection with the LES using the acquired ATM address of the LES, and based on the destination MAC address in the frame, the ATM of the LEC-B which is the data transfer destination. Inquire the address to the LES (). If the ATM address corresponding to the MAC address of LEC-B is registered in the address management table of LES, LES
-Return the ATM address of LEC-B to A (). LE
If the ATM address corresponding to the MAC address of LEC-B is not registered in the address management table of S,
The LES queries the BUS for the ATM address. The BUS inquires of all the LECs connected to the ATM switch network about the ATM address by broadcast (). The resulting ATM address of LEC-B is returned to LES. The LES registers the MAC address of the LEC-B and the ATM address in association with each other in the address management table, and returns the ATM address of the LEC-B to the LEC-A. The LEC-A establishes a connection with the LEC-B using the obtained ATM address, generates a cell from the frame received from the terminal, and transmits the cell to the LEC-B ().

FIG. 19 is a view for explaining an IP over ATM address resolution method. An ATM-ARP (Address Resolution Protocol) server is provided in the ATM switch network. ATM clients
A device that acts as a router between the existing LAN and the ATM switch network.
Is configured.

The procedure for the ATM client A, which is the ATM end device, to obtain the ATM address of the ATM client B is as follows. ATM clients A and A
At the time of initialization such as power-on, the TM client B
-Establish a connection with the ARP server. Then A
The TM-ARP server is composed of ATM client A and AT
An inquiry about the IP address is made to each of the M clients B, and each ATM client returns its own IP address to the ATM-ARP server (). The ATM-ARP server uses the IP address of each ATM client and the ATM
Create an address correspondence table (address management table). Upon receiving the IP packet from the terminal, the ATM client A receives the ATM of the ATM client B to which the IP packet is transferred based on the destination IP address in the IP packet.
The address is inquired to the ATM-ARP server (). The ATM-ARP server searches the address management table based on the IP address, and returns the ATM address of the ATM client B to the ATM client A (). The ATM client A establishes a connection with the ATM client B using the obtained ATM address, generates a cell from the IP packet received from the terminal, and transmits the cell to the ATM client B ().

[0007]

As described above, A
In order to resolve the TM address, the LAN emulation method requires a server such as LECS, LES and BUS, and the IPover ATM method requires ATM-A.
Requires an RP server. Further, when a failure occurs in any of these servers, the ATM address cannot be resolved, so that there is a problem that communication between the ATM end devices cannot be performed. In addition, there is a problem that access is concentrated on the server for address resolution and response time is reduced. In addition, the ATM client of the IPover ATM method has a problem that the communication with the server in the Internet layer referred to in the TCP / IP protocol system is inevitably a software process, and an overhead due to the software process is generated, thereby deteriorating the performance. is there.

An object of the present invention is to solve an ATM address by using an ATM end device without using a server.

[0009]

SUMMARY OF THE INVENTION According to the present invention, a terminal device and an A
The transmission device interposed between the TM switch network and the AT
The M address is resolved. This transmission apparatus receives, from another transmission apparatus, an ATM address of another transmission apparatus and a layer 3 address of a terminal apparatus connected to the other transmission apparatus, and registers it in a table. This table is referred to based on the layer 3 address of the data transmission destination terminal, and the ATM address of the corresponding other transmission device is acquired. Based on the acquired ATM address, the communication device communicates with another transmission device and communicates with the other transmission device. Means for transmitting a cell including the layer 3 address information. The present invention also provides
A network system including such a transmission device is characterized. The terminal device and the transmission device form a network such as an existing LAN that performs communication using a layer 2 address, and the transmission device performs communication using an ATM address.
A TM network is configured, and a network such as an IP network that communicates between terminals using a layer 3 address is configured.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a configuration diagram of a network system according to the present embodiment. The ATM switch network 24 is constituted by ATM switches 26-1 and 26-2 and transmits cells. Switching hubs (HUBs) 10-1 and 10-2 are connected to the ATM switch network 24. Existing L
The AN 22 is configured by a network that connects the switching HUB 10 and the terminal 20, and the switching HU
A frame is transmitted between B10 and terminal 20. The switching HUB 10 generally includes an ATM switch network 24.
A transmission / reception port 14 for transmitting / receiving cells to / from the ATM switch network 24, and a frame transmission / reception port 13 for transmitting / receiving frames to / from the terminal 20. Switching HUB
In () of the terminal 10 and the terminal 20, addresses of the terminal device are illustrated in the order of the ATM address, the MAC address, and the layer 3 address. In the present embodiment, the switching HUB 1
0 has no layer 3 address, but may have a layer 3 address. The terminal 20 does not have an ATM address.

The switching HUBs 10-1 and 10-
2 is referred to as a switching HUB 10. Frame transmission / reception port 13, cell transmission / reception port 1
4 and the terminal 20.

FIG. 2 is a diagram showing the internal configuration of the switching hub 10. Switching HUB 10 is a CPU
11, a main memory (memory) 12, a frame transmission / reception port 13, and a cell transmission / reception port 14. On the memory 12, an address management table 15, a terminal registration processing unit 16, an address exchange processing unit 17, a frame reception processing unit 18, and a cell reception processing unit 19 are provided. The address management table 15 is a table for registering address information of the terminal 20 connected to the own switching HUB 10 and the other switching HUB 10. Terminal registration processing unit 1
6 is a terminal 20 connected to the self-switching HUB 10
And the address information of the terminal 20 that has responded is registered in the address management table 15. The address exchange processing unit 17 registers the address information in the address management table 15 when receiving the address information from another switching HUB 10, and the terminal 2 connected to the own switching HUB 10.
When the address information of 0 is registered in the address management table 15, it is transmitted to another switching hub 10. The frame reception processing unit 18 receives a frame from the terminal 20 via the frame transmission / reception port 13, generates a cell having the ATM address of the switching HUB 10 to which the destination terminal 20 is connected with reference to the address management table 15. The cell is transmitted to the destination switching hub 10 via the cell transmission / reception port 14. The cell reception processing unit 19
Other switching HUB 1 via cell transmission / reception port 14
A cell is received from 0, a frame having the MAC address of the destination terminal 20 is generated with reference to the address management table 15, and the frame is transmitted to the destination terminal 20 via the frame transmission / reception port 13. Frame reception processing unit 18
The cell reception processing unit 19 is configured as hardware (firmware), and is executed by the CPU 11. Terminal registration processing unit 16 and address exchange processing unit 17
Performs effective processing only when registering the address information of a new terminal 20 or switching HUB 10 in the address management table 15 and has a small load on the CPU 11, so that it can be configured as software (program).

FIG. 3 is a diagram showing the data structure of the address management table 15. Each entry of the address management table 15 has an ATM address 31 and a MAC address 3
2, data items of the layer 3 address 33 and the connection port 34, and are provided corresponding to the terminal 20.
31 is a terminal 2 connected to the self-switching HUB 10
0, it does not apply, but other switching HUB1
In the case of the terminal 20 connected to 0, the ATM address of the switching HUB 10 to which the terminal 20 is connected is set. 32 has M as a layer 2 address of the terminal 20.
In the AC address 33, a layer 3 address of the terminal 20, such as an IP address, is set. In the field 34, the port number of the frame transmission / reception port 13 is set for the terminal 20 connected to the own switching HUB 10, and the port number of the cell transmission / reception port 14 is set for the terminal 20 connected to another switching HUB 10. Is set. In an initial state such as when the power of the switching hub 10 is turned on, the address management table 15 is empty.

FIG. 4 is a flowchart showing the flow of the processing of the terminal registration processing section 16. The terminal registration processing unit 16
Execution is started when the power of the switching hub 10 is turned on, and the processing is continued until the power is turned off. The terminal registration processing unit 16 starts a terminal registration timer (step 42), and performs frame negotiation on all ports of the terminals 20 connected to the frame transmission / reception port 13 whose terminals (MAC addresses) are not registered in the address management table 15. Polling is performed via the transmission / reception port 13 (step 43). If there is a response from the terminal 20 to the polling (step 44 YES), the terminal 20 that has returned the response
MAC address, layer 3 address and its terminal 2
The number of the port to which 0 is connected is stored in the address management table 1
5, one entry of MAC address 32,
It is registered in the layer 3 address 33 and the connection port 34 (step 45). Next, it is determined whether or not the terminal registration timer has timed out (step 46). If the timeout has not occurred (NO in step 46), the process waits in step 46 until the terminal registration timer times out. When the terminal registration timer times out (step 46YE
S), reset the terminal registration timer (step 47),
Return to step 42. When there is no response from the terminal 20 to the polling (step 44 NO), the process goes to step 46. Generally, it is sufficient to inquire of the terminal 20 to which the switching HUB 10 is connected for address information, or to transmit the address information from the connected terminal 20 to the switching HUB 10, and it is not limited to the polling means of the switching HUB 10. Absent.

FIG. 5A shows a switching HUB 10-.
1 shows a data example of the address management table 15 of FIG. The terminal 20 responds to the polling of the switching HUB 10-1.
1 shows address information registered in the address management table 15 when the terminal 20-1 and the terminal 20-2 return a response. FIG.
(B) shows a data example of the address management table 15 of the switching hub 10-2. Switching HUB1
The address information registered in the address management table 15 when the terminal 20-3 returns a response to the polling of 0-2.

FIG. 6 shows a switching HUB 10-1 and a switching HUB 10- via an ATM switch network 24.
FIG. 3 is a diagram showing a data format of a cell that contains address information transmitted between the cell and the cell. The transmission source ATM address and the MAC of the connected terminal 20 are stored in the 48-byte cell data portion.
An address and a layer 3 address are set.

FIG. 7 is a flowchart showing the flow of the processing of the address exchange processing unit 17. The processing of the address exchange processing unit 17 is performed when new address information is registered in the address management table 15 and when another switching HU is used.
This is executed when address information is received from B10.
First, another switching H through the cell transmission / reception port 14
It is determined whether the address information is received from the UB 10 (step 52). If the address information is received from another switching hub 10 (step 52 YES), the transmitted address information is registered as one entry of the address management table 15 (step 53). The connection port 34 includes the cell transmission / reception port 1 that has received the address information.
4 is set. However, if the same entry is already registered in the address management table 15, it is discarded. The terminal 20 is newly added to the address management table 15.
When the address information is registered (step 52 NO and step 54 YES), polling is performed from all the ports of the cell transmission / reception port 14 to the other switching hubs 10 via the ATM switch network 24 (step 55). When there is a response to the polling (step 56 YES), the ATM address of the own device and the M of the entry newly registered in the address management table 15 are obtained.
The AC address 32 and the layer 3 address 33 are transmitted to the switching HUB 10 that has responded (step 5).
7). If there is no response to polling (step 5
6NO), and terminate the process. Address management table 15
If the address information of the terminal 20 has not been newly registered (NO in step 54), the process ends. It responds when polling is received from another switching hub 10. In general, other switching HUB1
The address information may be obtained by inquiring the address information to 0, or may be obtained by broadcasting the address information, and is not limited to the polling means.

FIG. 8A shows a switching HUB 10-.
2 has been registered in the address management table 15 of the terminal 20-3, the switching HUB
The address information of the terminal 20-3 added to the address management table 15 of 10-1 is shown. FIG. 8B shows the address management table 15 of the switching hub 10-1.
3 shows the address information of the terminal 20-1 and the terminal 20-2 added to the address management table 15 of the switching HUB 10-2 because the address information of the terminal 20-1 and the terminal 20-2 are registered. The MAC address 3 of the terminal 20 connected to another switching hub 10
2 is not referred to, but is registered according to the format of the address management table 15 in the present embodiment. MA of terminal 20 connected to another switching hub 10
It is not necessary to acquire the C address and thus not to register.

FIG. 9 shows address information when the terminal 20-4 is additionally registered when the registered contents of the address management table 15 of the switching HUB 10-2 are as shown in FIG. 8B.

FIG. 10 shows that the switching HUB 10-2 is registered when the address information of the terminal 20-4 is registered in the address management table 15 of the switching HUB 10-2.
1 terminal 20- added to the address management table 15
4 shows address information.

FIG. 11 is a diagram showing the network hierarchy of the terminal 20 and the data structure of transmission data created in each layer. In this example, ftp (file transfer protocol) is used as an application layer protocol, TCP is used as a transport layer protocol, IP (Internet layer) is used as a network layer protocol, and Ethernet (Ethernet) is used as a data link layer protocol.
Is used. In ftp, f
The tp header is added to generate ftp data. T
In CP, a TCP header is added to ftp data,
P data is generated. In IP, IP data (IP packet) is generated by adding an IP header to TCP data. In Ethernet, a frame is generated by adding a frame header and a trailer to IP data.

FIG. 12 shows that a source IP address (for example, α1) and a destination IP address (for example, β2) are included in an IP header.
It is a figure showing that is set.

FIG. 13 shows the transmission source MAC in the frame header.
It is a figure showing that an address (for example, c) and a destination MAC address (for example, a) are set.

FIG. 14 is a diagram showing the network layer of the switching HUB 10 and the structure of data created or transmitted / received at each layer. In the data link layer Ethernet, frames are transmitted and received.
P data (IP packet) is generated, and AAL (ATM adaptation layer: ATMA) of the data link layer is generated.
A cell is generated in the (Daption Layer), and the cell is transmitted and received in the ATM layer.

FIG. 15 is a flowchart showing the processing procedure of the frame reception processing unit 18. Upon receiving a frame from the terminal 20 via the frame transmission / reception port 13, the frame reception processing unit 18 determines whether or not the transmission destination MAC address in the frame header matches its own MAC address (step 62). If they match (step 62 YES), an IP packet is extracted from the frame (step 63). Next, the address management table 15 is searched based on the destination IP address in the IP header (step 64). IP that matches the destination IP address
If there is an entry for the terminal 20 having the address (YES in step 65), the switching HUB 10 having the ATM address of the transmission destination can be specified, so that it is determined whether an ATM connection has been established with the switching HUB 10 having the ATM address. (Step 6
6). If the ATM connection has not been established (NO in step 66), a VPI (Virtual Path Ide) is negotiated with the partner switching HUB 10 using the ATM address of the entry.
ntifier and VCI (Virtual Chan)
(Nel Identifier), establish an ATM connection (step 67), and go to step 68. If the ATM connection has been established (step 66 YES), the VPI and VC are immediately added to the cell header.
I is set (step 68), and the IP packet in the received frame is divided every 48 bytes and set in the cell data part (step 69). Steps 68 and 69 are AAL processing. Next, a cell is transmitted from a port among the cell transmission / reception ports 14 registered in the connection port 34 of the entry in the address management table 15 (step 70). If the destination MAC address in the frame header does not match the own MAC address (NO in step 62), and if there is no entry of the terminal 20 having the IP address matching the destination IP address in the address management table 15 (NO in step 65), The processing of the frame reception processing unit 18 ends.

FIG. 16 is a flowchart showing the flow of the processing of the cell reception processing section 19. Cell reception processing section 19
Is the partner switching H via the cell transmission / reception port 14.
When a cell is received from the UB 10, an IP packet is assembled from at least one cell data (step 7).
2). Next, the address management table 15 is searched based on the destination IP address in the IP header (step 7).
3). If there is an entry for terminal 20 having an IP address that matches the destination IP address (step 74YE
S) Since the terminal 20 having the transmission destination MAC address can be specified, the MAC address is set to the transmission destination MAC address in the frame header (step 75). Next, the own MAC is added to the source MAC address in the frame header.
An address is set (step 76). For example, FIG.
The MAC address is set as shown in FIG. Next, an IP packet is set in the data portion of the frame (step 7).
7). Next, the generated frame is stored in the address management table 1
5 is transmitted from a port among the frame transmission / reception ports 13 registered in the connection port 34 of the entry (step 78). Destination IP in the address management table 15
If there is no entry of the terminal 20 having the IP address that matches the address (NO in step 74), the processing of the cell reception processing unit 19 ends.

The terminal 20 that has received the frame from the switching hub 10 recognizes that the frame is addressed to itself because the destination MAC address in the frame header matches the own MAC address. The received frame is sequentially passed to the upper layer, and finally ftp receives data. The same applies to other protocols such as telnet and SMTP as application layer protocols.

According to the present embodiment, the terminal registration processing unit 16
Performs effective processing only on terminals that have not been registered in the address management table 15, so that the CPU load is small. Further, the address exchange processing unit 17 involves communication with another switching HUB 10 via the ATM switch network 24. The processing is performed when the address information of the new terminal is registered in the address management table 15 and in the initial state. This is executed when the address information is received from the switching HUB 10 and the processing load is small, so that the CPU load is small. The frame reception processing unit 18 and the cell reception processing unit 19 perform processing related to the Internet layer which is a network layer, but can execute address resolution only by referring to the address management table 15, and use an ATM switch network for address resolution. Since no communication is performed via the H.24, it can be configured by hardware and its CPU overhead is small.

FIG. 20 is a diagram showing the internal configuration of a switching hub 10 'in another embodiment. The difference from the switching hub 10 is that the terminal registration processing unit 16 ′
And an address exchange processing unit 17 '. Other points are the same as those of the switching hub 10.

FIG. 21 shows the switching HUB 10'-1 and the switching HUB 1 via the ATM switch network 24.
It is a figure which shows the data format of the cell which accommodates the address information transmitted between 0'-2. Hereinafter, this cell is called an address exchange cell. The 48-byte cell data section includes a registration / deletion identification bit section, an address request bit section, an ATM address section, a MAC address section, and a layer 3 address section. The registration / deletion identification bit part is a bit for identifying whether the transmitted address exchange cell requests registration of an address or requests deletion of an address. In the case of registration, 1 is deleted. 0 in case
Set. In the address request bit portion, 1 is set when requesting transmission of address information possessed by the switching HUB 10 'of the transmission destination, and 0 is set when requesting transmission of address information is not requested.

FIG. 22, FIG. 23, FIG. 24 and FIG. 25 are flowcharts showing the processing flow of the terminal registration processing section 16 ′. In FIG. 22, the terminal registration processing unit 16 'starts executing when the power of the switching HUB 10' is turned on, and continues processing until the power is turned off. The terminal registration processing section 16 'starts a terminal registration timer (step 1).
01), polling is performed from all ports of the frame transmission / reception port 13 (step 102). When there is a response from the terminal 20 to the polling (step 103YE
S), it is determined whether (the MAC address of) the terminal 20 that has returned the response is already registered in the address management table 15 (step 104). If not registered (step 104 NO), the MAC address of the terminal that returned the response, the layer 3 address, and the number of the port to which the terminal 20 is connected are set as one entry of the address management table 15, and the MAC address 32 and the layer 3 respectively. Register in the address 33 and the connection port 34 (step 1
05).

It is determined whether or not an entry of another terminal exists in the address management table 15 (step 106).
If there is (YES in step 106), the process proceeds to FIG. 23, where 1 is set in the registration / deletion identification bit portion of the address exchange cell.
, The address request bit is set to 0, the ATM address is set to the own ATM address, and the MAC address and the layer 3 address of the terminal registered in the MAC address and the layer 3 address are set (step 107). Polling is performed from all of the cell transmission / reception ports 14 to the other switching hubs 10 'via the ATM switch network 24 (step 108). If there is a response to the polling (step 109, YES), the address exchange cell created in step 107 is transmitted to the switching HUB 10 'that has returned the response (step 110), and step 1 is executed.
Go to 21. If there is no response to the polling (step 109 NO), the process proceeds to step 121.

If there is no entry of another terminal in the address management table 15 (step 106 NO), the contents of the address management table 15 are empty when the power of the switching HUB 10 ′ is turned on. 1 in the registration / deletion identification bit of the exchange cell
Is set in the address request bit, the ATM address of the terminal registered in the MAC address part and the layer 3 address part in the ATM address part, and the layer 3 address (step 111). Polling is performed from all of the cell transmission / reception ports 14 to the other switching HUB 10 'via the ATM switch network 24 (step 112). If there is a response to the polling (step 113 YES), the address exchange cell created in step 111 is transmitted to the switching HUB 10 'that has returned the response (step 114), and step 1 is executed.
Go to 21. If there is no response to the polling (NO in step 113), the process proceeds to step 121.

When there is no response from terminal 20 to polling performed from frame transmission / reception port 13 (step 103)
NO), since the terminal 20 has been disconnected from the connection of the switching HUB 10 ', the process proceeds to FIG. 25 to determine whether or not there is an entry in the connection port 34 of the address management table 15 in which a port with no response is registered. Is determined (step 115 YES), the entry in which the port not responding is registered is deleted from the address management table 15 (step 116). 0 in the registration / deletion identification bit portion of the address exchange cell, 0 in the address request bit, own ATM address in the ATM address portion, MAC address of the terminal to be deleted in the MAC address portion and the layer 3 address portion, layer 3 address Is set (step 117). Polling is performed from all of the cell transmission / reception ports 14 to the other switching HUBs 10 'via the ATM switch network 24 (step 118). If there is a response to the polling (step 119 YES), the switching HUB that has returned the response
The address exchange cell created in step 117 is transmitted to 10 '(step 120), and the procedure goes to step 121. When there is no response to polling (step 119N
O), go to step 121; Address management table 1
It is determined whether or not there is an entry in which a non-response port is registered in the connection port 34 of No. 5 (step 115: NO). It should be noted that one response to polling of terminal 20
May be deleted from the address management table 15 when there is no response to a predetermined number of polls.

Returning to FIG. 22, the frame transmission / reception port 13
If (the MAC address of) the terminal 20 responding to the polling performed from is already registered in the address management table (YES in step 104), the process proceeds to step 121. Next, it is determined whether or not the terminal registration timer has timed out (step 121). If the timeout has not occurred (NO in step 121), the process waits in step 121 until the terminal registration timer times out. When the terminal registration timer times out (step 121 YES), the terminal registration timer is reset (step 122), and the process returns to step 101.

FIG. 26 is a flow chart showing the flow of processing of the address exchange processing section 17 '. The process of the address exchange processing unit 17 'is executed when address information is received from another switching hub 10'. First, another switching HUB 1 is transmitted via the cell transmission / reception port 14.
It is determined whether the received cell is an address exchange cell received from 0 '(step 201). If the cell is an address exchange cell received from another switching hub 10 '(step 20)
1YES), it is determined whether or not 1 is entered in the registration / deletion bit portion of the received address exchange cell (step 2).
02). When 1 is entered in the registration / deletion bit portion (step 202, YES), the received address information is registered as one entry of the address management table 15 (step 203). The connection port 34 sets the port number of the cell transmission / reception port 14 that has received the address information. Next, it is determined whether or not 1 is set in the address request bit portion of the received address exchange cell. If 1 is set (step 204 YES), 1 is set in the registration / deletion bit portion, and 0 is set in the address request bit portion. Then, an address exchange cell is created in which the ATM address is set in the ATM address part, the MAC address part, and the MAC address and the layer 3 address of each terminal directly connected to the terminal are set in the layer 3 address part (step 205). The created address exchange cell is transmitted to the switching HUB 10 'that transmitted the address information in step 201 (step 20).
6), end the address exchange processing. Since one cell contains address information of one terminal, the address exchange processing unit 17 'transmits cells by the number of directly connected terminals. When 1 is not included in the address request bit portion of the received address exchange cell (step 204N)
O), the address exchange processing ends. When 1 is not included in the registration / deletion bit portion of the received address exchange cell (step 202 NO), the same entry as the received address information is deleted from the address management table 15 (step 207), and the address exchange processing is ended. . However, if the same entry as the received address information does not exist in the address management table 15, it is discarded.

According to the other embodiment, the terminal 20 that does not respond to the polling can be deleted from the address management table 15 of the self-switching HUB 10 'and also from the address management table 15 of the other switching HUB 10'. Thus, the terminal 20 can be removed from the connection of the switching HUB 10 ′ and can cope with the movement of the terminal 20 connected to another port or another switching HUB 10 ′. Also, when the switching HUB 10 'is turned on after being turned on, the address information can be collected from the other switching HUB 10' which has been started before.

FIGS. 27 and 28 are flow charts showing the flow of processing of the terminal registration processing section 16 'in still another embodiment. The terminal registration processing unit 16 'executes a terminal registration addition process and a terminal registration deletion process.

The flow of the terminal registration addition process will be described with reference to FIG. When the frame transmission / reception port 13 of the switching HUB 10 ′ detects a new electrical connection by the terminal 20, the terminal registration addition process is started, and address information is transmitted to the terminal 20 connected to the port that has detected the electrical connection. Request (step 1001). The MAC address of the terminal 20 that has returned the address information, the layer 3 address, and the port number to which the terminal 20 is connected are registered as one entry of the address management table 15 in the MAC address 32, the layer 3 address 33, and the connection port 34, respectively. (Step 1002). If the same M
If the entry of the AC address 32 has already been registered, the entry is updated with the received address information. Next, it is determined whether or not an entry of another terminal exists in the address management table 15 (step 100).
3) If an entry of another terminal exists (step 1)
003 YES), 1 in the registration / deletion identification bit part of the address exchange cell, 0 in the address request bit, own ATM address in the ATM address part, MAC address part,
MAC address of the terminal registered in the layer 3 address part,
A layer 3 address is set (step 1007). Polling is performed from all of the cell transmission / reception ports 14 to the other switching HUBs 10 'via the ATM switch network 24 (step 1008). If there is a response to polling (step 1009 YES),
Step 10 returns to the switching hub 10 'that has returned the response.
07 is transmitted (step 1).
010), the terminal registration adding process ends. If there is no response to the polling (step 1009 NO), the terminal registration adding process ends.

When there is no entry of another terminal in the address management table 15 (step 1003 NO), the contents of the address management table 15 are empty when the power of the switching HUB 10 ′ is turned on. Set 1 in the deletion identification bit, set 1 in the address request bit, set its own ATM address in the ATM address, and set the MAC address and layer 3 address of the terminal registered in the MAC address and the layer 3 address (step 1011). ). Polling is performed from all ports of the cell transmission / reception port 14 to another switching HUB 10 'via the ATM switch network 24 (step 1012). If there is a response to the polling (step 1013 YES), the switching H that has returned the response
The address exchange cell created in step 1011 is transmitted to the UB 10 '(step 1014), and the terminal registration adding process ends. If there is no response to the polling (step 1013 NO), the terminal registration adding process ends.

The flow of the terminal registration deletion processing will be described with reference to FIG. When the change from the electrical connection to the disconnection is detected at the frame transmission / reception port 13 of the switching HUB 10 ′, the terminal registration deletion process starts, and the address information of the terminal 20 connected to the port that has detected the disconnection of the electrical connection. Is deleted from the address management table 15 (step 2001). 0 in the register / delete identification bit part of the address exchange cell, 0 in the address request bit, and AT
The ATM address of the terminal to be deleted and the layer 3 address of the terminal to be deleted are set in the M address section and the MAC address section and the layer 3 address section (step 200).
2). AT from all ports of cell transmission / reception port 14
Another switching HUB 1 via the M switch network 24
Polling is performed on 0 '(step 2003).
If there is a response to polling (step 2004)
YES), the address exchange cell created in step 2002 is transmitted to the switching HUB 10 'that has returned the response (step 2005), and the terminal registration deletion processing ends.
When there is no response to polling (step 2004)
NO), end the terminal registration deletion process.

Referring to FIG. 29, switching HUB 10 '
An example of detection of electrical connection and disconnection at the frame transmission / reception port 13 will be described. When the terminal connected to the frame transmission / reception port is activated, the NIC (Network
(orkInterfaceCard) starts transmitting a heartbeat signal. When detecting the start of transmission of the heartbeat signal, the connection recognition circuit of the switching hub 10 'interrupts the CPU 11. The CPU 11 that has received the interrupt starts the terminal registration adding process. Further, the connection recognition circuit of the switching hub 10 'is connected to the terminal 20.
When the CPU 11 detects no heartbeat signal from the
Interrupt Upon receiving the interrupt, the CPU 11 starts the terminal registration deletion process.

According to still another embodiment shown in FIGS. 27 to 29, the terminal registration processing unit 16 'removes and connects the terminal 20 to the switching hub 10' without performing polling processing on the terminal 20. Can be detected, CPU1
1 overhead can be reduced. Further, it is possible to detect removal and connection of the terminal 20 to the switching HUB 10 ′ in real time without being affected by the polling interval, and to delete and add the address management table 15.

[0045]

As described above, according to the present invention, a transmission device such as a switching hub interposed between a terminal device and an ATM switch network resolves an ATM address. , And an economical and highly reliable network system can be constructed.
Further, this transmission device can avoid software overhead for address resolution, and can reduce the conventional IPo.
A high-performance transmission device can be provided as compared with a verATM ATM client.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a network system according to an embodiment.

FIG. 2 is a diagram illustrating an internal configuration of a switching hub 10 according to the embodiment.

FIG. 3 is a diagram illustrating a data configuration of an address management table 15 according to the embodiment.

FIG. 4 is a flowchart illustrating a processing flow of a terminal registration processing unit 16 according to the embodiment.

FIG. 5 is a diagram showing a data example of an address management table 15;

FIG. 6 is a diagram showing a data format of a cell transmitting address information according to the embodiment.

FIG. 7 is a flowchart illustrating a processing procedure of an address exchange processing unit 17 according to the embodiment.

FIG. 8 is a diagram showing an example of address information added to the address management table 15;

FIG. 9 is a diagram illustrating an example of address information added to the address management table 15;

FIG. 10 is a diagram illustrating an example of address information added to the address management table 15 of the other switching HUB 10;

FIG. 11 is a diagram illustrating a network hierarchy of a terminal 20 and a configuration of transmission data created in each layer.

FIG. 12 is a diagram illustrating an example of address information of an IP header.

FIG. 13 is a diagram illustrating an example of address information of a frame header.

FIG. 14 is a diagram showing a network layer of the switching hub 10 and a configuration of data created or transmitted / received in each layer.

FIG. 15 is a flowchart illustrating a processing procedure of a frame reception processing unit 18 according to the embodiment.

FIG. 16 is a flowchart illustrating a processing procedure of a cell reception processing unit 19 according to the embodiment.

FIG. 17 is a diagram illustrating an example of address information of a frame header.

FIG. 18 is a diagram illustrating a LAN emulation address resolution method.

FIG. 19 is a view for explaining an address solution method of the IPover ATM system.

FIG. 20 is a diagram illustrating an internal configuration of a switching HUB 10 ′ of another embodiment.

FIG. 21 is a diagram illustrating a data format of a cell transmitting address information according to another embodiment.

FIG. 22 is a flowchart illustrating a flow of processing of a terminal registration processing unit 16 ′ of another embodiment.

FIG. 23 is a flowchart (continued) showing the processing flow of the terminal registration processing unit 16 ′ of another embodiment.

FIG. 24 is a flowchart (continued) showing the flow of the process of the terminal registration processing unit 16 ′ of another embodiment.

FIG. 25 is a flowchart (continued) showing the flow of processing of the terminal registration processing unit 16 ′ of another embodiment.

FIG. 26 is a flowchart showing a processing procedure of an address exchange processing unit 17 'of another embodiment.

FIG. 27 is a flowchart illustrating a flow of a terminal registration adding process of a terminal registration processing unit 16 ′ of another embodiment.

FIG. 28 is a flowchart illustrating a flow of a terminal registration deletion process of a terminal registration processing unit 16 ′ of another embodiment.

FIG. 29 is a diagram illustrating an example of detection of electrical connection and disconnection at a frame transmission / reception port 13 of a switching HUB 10 ′ according to another embodiment.

[Explanation of symbols]

10: Switching HUB, 13: Frame transmission / reception port, 14: Cell transmission / reception port, 15: Address management table, 16: Terminal registration processing unit, 17: Address exchange processing unit, 18: Frame reception processing unit, 19: Cell reception processing unit , 31: ATM address, 32: MAC address, 3
3: Layer 3 address, 34: connection port

Continued on the front page (72) Inventor Kei Toga 890 Kashimada, Saiwai-ku, Kawasaki-shi, Kanagawa Prefecture Information Systems Division, Hitachi, Ltd.

Claims (7)

[Claims] An ATM switch is provided between a terminal device for performing terminal-to-terminal communication using a layer 3 address and an ATM switch network.
A transmission device for resolving an address, wherein the transmission device receives, from another transmission device, an ATM address of the other transmission device and a layer 3 address of a terminal device connected to the other transmission device, and registers in a table. Based on the layer 3 address of the data transmission destination terminal received from the connected terminal device, and referring to the table for the A of the corresponding other transmission device.
It acquires a TM address, communicates with another transmission device based on the acquired ATM address, and performs layer 3 of the data transmission destination terminal.
Means for transmitting a cell containing address information. A transmission apparatus for resolving an ATM address. 2. The transmission apparatus further comprises means for receiving a layer 3 address and a layer 2 address of a terminal apparatus to be connected and registering them in a table, and a terminal connected to another transmission apparatus via an ATM switch network. The layer 3 address of the connected terminal device is acquired by referring to the table based on the layer 3 address of the data transmission destination terminal received from the device, and the layer 3 address information received by the terminal device having the acquired layer 2 address 2. A transmission apparatus for resolving an ATM address according to claim 1, further comprising means for transmitting data including: 3. An ATM switch network, a terminal device for performing terminal-to-terminal communication using a layer 3 address, a terminal device and an ATM
A transmission device interposed between the switching device and a switching device, which constitutes a network for performing communication with a terminal device using a layer 2 address, and exchanges an ATM address with another transmission device via an ATM switching network. A network system comprising: a communication device that performs communication by using the transmission device to resolve an ATM address at the time of terminal-to-terminal communication, wherein the transmission device is configured to transmit an ATM address of another transmission device from another transmission device and another transmission device. Means for receiving the layer 3 address of the terminal device connected to the terminal device and registering it in the table, and referring to the table based on the layer 3 address of the data transmission destination terminal received from the connected terminal device, to correspond to another corresponding device. Acquires the ATM address of the transmission device, communicates with another transmission device based on the acquired ATM address, and transmits a cell including the layer 3 address information of the data transmission destination terminal. Network system characterized by a means that. 4. An ATM interposed between a terminal device for performing terminal-to-terminal communication using a layer 3 address and an ATM switch network.
A transmission device for resolving an address, wherein the transmission device receives a layer 3 address from a terminal device to be connected, registers the address in a table, and registers the ATM address of the transmission device with another transmission device as an ATM address of the transmission device. Means for transmitting the layer 3 address of the terminal device to be transmitted, and means for receiving the ATM address of the other transmission device and the layer 3 address of the terminal device connected to the other transmission device from another transmission device and registering them in a table. And obtains the ATM address of the corresponding other transmission device by referring to the table based on the layer 3 address of the data transmission destination terminal received from the connected terminal device, and performs another transmission based on the obtained ATM address. Means for communicating with the device and transmitting a cell including the layer 3 address information of the data transmission destination terminal.
A transmission device that performs address resolution. 5. The transmission apparatus is further connected with reference to the table based on a layer 3 address of a data transmission destination terminal received from a terminal apparatus connected to another transmission apparatus via an ATM switch network. Layer 3 applicable in the terminal device
5. A transmission apparatus for resolving an ATM address according to claim 4, further comprising means for transmitting data including the received layer 3 address information to a terminal apparatus having an address. 6. The transmission device further polls a connected terminal device and, when there is no response, deletes the layer 3 address of the terminal device that has not responded from the table and does not respond to another transmission device. 5. The transmission apparatus for resolving an ATM address according to claim 4, further comprising means for requesting deletion of the layer 3 address of the terminal device from the table. 7. The transmission device according to claim 1, further comprising: detecting an electrical connection with a terminal device to be further connected to the transmission device, the transmission device comprising:
Upon detecting an electrical disconnection between the address receiving means and the terminal device to be connected, the layer 3 address of the terminal device that has detected the disconnection is deleted from the table and the connection to another transmission device is disconnected. 5. The transmission apparatus for resolving an ATM address according to claim 4, further comprising means for requesting deletion of the layer 3 address of the terminal device from the table.