JPH04341033A - Lan-fmbs connection system - Google Patents

Abstract

PURPOSE:To attain high speed data communication by realizing LAN-ISDN communication with respect to the LAN-FMBS connection system in which the interconnection between the LAN and the FMBS being the ISDN packet mode service is attained. CONSTITUTION:A MAC address and a virtual subaddress are assigned to LAN terminal equipments 4,5, and a virtual MAC address and a subaddress are allocated to an ISDN terminal equipment 6. Repeaters 7,8 interconnect the LANs 1,2 and the ISDN3 of the FMBS system based on the MAC address or the subaddress designated as a communication destination address. In this interconnection, the repeaters 7,8 convert the frame format of the LAN and the frame format of the ISDN mutually independently of the path, i.e., the ISDN communication path.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to FM, which is an ISDN packet mode service for realizing high-speed data communication.
BS (Frame Mode Bearer Serv)
LA standardized by ice) and IEEE802.2
The present invention relates to a LAN-FMBS connection method that realizes interconnection with N (Local Area Network), and particularly relates to a LAN-FMBS connection method that defines addressing, frame conversion, and address data mapping.

FMBS is a high-speed packet service that realizes high-speed data transmission by simplifying the functions of ISDN layer 2 and making a part of layer 2 and layers 3 and above transparent. FMBS includes frame relay and frame switching, and the present invention assumes the case of frame relay.

[0003] In FMBS frame relay, layer 1
is similar to conventional ISDN, but Layer 2 has basic functions such as frame identification, consistency checking, frame multiplexing, frame disassembly, zero bit insertion/extraction, and transmission error detection (LA
PD core function, Link AccessProcedu
re on the D-channel), and does not support functions such as flow control and frame retransmission control due to errors. Correspondingly, high-speed transmission within the network is possible, and end-to-end throughput can be greatly improved compared to packet exchange.

[0004] Furthermore, in FMBS, part of layer 2 (LA
Layer 2
A part of the layer 3 and layers 3 and above are transparent between nodes, and therefore high transparency can be achieved.

[0005] By interconnecting this FMBS and LAN,
Performs communication between an AN terminal and a remote LAN terminal, and
The present invention is useful when realizing communication between an N terminal and a remote ISDN terminal at the same time.
A relay device IWU (Inter Wor
King Unit).

[0006]

[Prior Art] Conventionally, when realizing a LAN-WAN-LAN connection, a gateway is used as a relay device, and a WA
N (Wide Area Network) was connected via a dedicated line, DDX network, ISDN network, etc. However, leased lines are expensive, packets on DDX and ISDN networks are slow, and line switching on DDX and ISDN networks is based on an hourly billing system, so charges are incurred regardless of whether data is transferred or not, making it expensive. For these reasons, it is not easy to achieve economically satisfactory high-speed data transmission, and therefore there has been a demand for economical and high-speed data transmission.

On the other hand, in recent years, as the quality of transmission paths has improved, the probability of transmission path errors occurring has become extremely small. Furthermore, the mainstream belief is that communication protocols such as flow control are more efficient in transmission if users independently support them in higher layers than the network layer. Therefore, the FMBS frame does not perform node-to-node flow control or error control at the layer 2 level, which was done in conventional ISDN packet networks, and improves throughput to achieve high-speed data transmission. A relay was considered.

FIG. 13 is a diagram showing a conventional FMBS frame relay protocol stack when LAN terminals are connected via a LAN and an FMBS. In the figure, 11 and 12 indicate the protocol stack of the LAN terminal.
3,14 is the protocol stack in LAN, 15,1 is
6, 17, and 18 indicate protocol stacks in FMBS. As shown in Figure 13, in FMBS frame relay,
The functions up to the LAPD core of Layer 2 are matched, and upper layers of Layer 2 and above are transmitted transparently within the network.

FIG. 14 shows the conventional FMBS frame relay protocol stack shown in FIG.
It is a diagram showing E (User Plane, which corresponds to B channel) and C-PLANE (Control Plane, which corresponds to D channel). 19,20
is the protocol stack of U-PLANE, and 21
, 22 is the protocol stack of C-PLANE. In the case of a LAN-FMBS-LAN connection as shown in FIG.
Since the communication is to a network (ANWS), communication between LAN terminals can be realized using conventional connection technology such as a remote bridge as long as a communication path (virtual circuit) on the WAN (ISDN) is established. In other words, the address that specifies the other terminal from the LAN terminal can be unified to the MAC address, and the MAC frame and D
LCI (DataLink Connection I)
Conversion of the ``dentifier'' frame can also be performed simply by encapsulation.

0010

[Problems to be Solved by the Invention] However, when attempting to realize a connection between a LAN terminal and an ISDN terminal as shown in FIG. 15, rather than between LAN terminals, the following problems arise. Figure 15 shows a conventional LAN terminal and ISDN
FIG. 3 is a diagram showing a protocol stack in connection with a terminal.

(1) Since the address system used in the LAN 25 and the address system in the ISDN 26 are different, the communication partner is specified from the LAN terminal 27 to the ISDN terminal 28 or vice versa using the conventional addressing method. That was impossible.

(2) Therefore, in order to specify the communication partner, in the relay device IWU 29, from the LAN 25 to the IS
There is a MAC (Media Access) in the DN26 direction.
In addition to inputting a control frame, it is also necessary to specify the route (ISDN number) through which the signal should be sent. Also, from ISDN26 to LAN25, DLCI
and the route to send the signal (ISDN
number) had to be specified.

(3) Since the frame format of LAN25 and the frame format of ISDN26 are different, in relay device IWU29, LAN25 and I
When interconnecting with SDN26, it was necessary to convert the frame format.

The present invention has been made in view of the above points, and is applicable not only to LAN-WAN-LAN communication, but also to
It is an object of the present invention to provide a LAN-FMBS connection method that simultaneously realizes LAN-ISDN communication and enables data transmission that takes advantage of the high-speed characteristics of FMBS frame relay.

Another object of the present invention is to manage real addresses and virtual addresses assigned to LAN terminals and ISDN terminals in the same table, and to enable address searches and frame searches with a smaller memory capacity. The purpose of the present invention is to provide a LAN-FMBS connection method.

[0016]

[Means for Solving the Problems] According to the present invention, in order to achieve the above object, as shown in FIG. In the method, the LAN1,
LAN terminals 4 and 5 connected to ISDN 2 and assigned a MAC address and a virtual subaddress, and ISDN terminal 6 connected to the ISDN 3 and assigned a virtual MAC address and subaddress, designated as the communication partner address. A LAN-FMBS connection system is provided, which is characterized in that it has relay devices 7 and 8 that interconnect the LANs 1 and 2 and the FMBS ISDN 3 based on the MAC address or sub-address.

[0017] Furthermore, the relay devices 7 and 8 are connected to the LAN
and the ISDN frame format depending on the route. Further, the relay devices 7 and 8 have a table for mutually converting the LAN frame format and the ISDN frame format.

Furthermore, the table is searched by a hashing method that allows access using multiple search keys.

[0019]

[Operation] The LAN terminals 4 and 5 are assigned a MAC address and a virtual subaddress, and the ISDN terminal 6 is assigned a MAC address and a virtual subaddress.
Since a virtual MAC address and a subaddress are assigned, the relay devices 7 and 8 perform LA based on the MAC address or subaddress specified as the communication partner address.
N1, 2 and FMBS ISDN 3 are interconnected.

[0020] For this interconnection, the relay devices 7,
8 mutually converts the LAN frame format and the ISDN frame format depending on the route, that is, the ISDN communication path.

[0021] This conversion uses a table that can be searched by a hash method that can be accessed using a plurality of search keys.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 is a network diagram of a LAN and an FMBS-based ISDN in which two LAN terminals and an ISDN terminal are connected. LAN terminal (LANWS) 31, 32
are connected to LANs 33 and 34, respectively, and LAN 33 is connected to an FMBS ISD via a relay device (IWU) 35.
The LAN 34 is connected to the ISDN 36 via a relay unit (IWU) 37. The relay devices 35 and 37 are
For example, it consists of a workstation. An ISDN terminal (ISDNWS) 38 is further connected to the ISDN 36. Although only one terminal 31, 32, and 38 are shown in the figure, in reality, a plurality of each terminal exists. Route a is LA
The communication route between N terminals 31 and 32 is shown, and route b is L.
A communication route between the AN terminal 31 and the ISDN terminal 38 is shown.

[0023] Generally, in order to specify a LAN terminal as a communication partner, M
Use AC address. ISDN terminals do not have this MAC address. Therefore, a virtual MA is installed on the ISDN terminal.
Assign C address. This makes it possible to specify an ISDN terminal as if it were a LAN terminal. On the other hand, the ISDN subaddress Sd is one DSU (Digital Service Uni
t) is commonly used to identify multiple ISDN terminals connected to a bus; LAN terminals do not have this. Therefore, a virtual subaddress is assigned to the LAN terminal. This allows the LAN terminal to behave as if it were an ISDN.
It becomes possible to specify it as if it were a terminal.

Sub-addresses and MAC addresses, including virtual sub-addresses and virtual MAC addresses, are managed for each relay device and stored in the relay device as a table.

FIG. 3 is a diagram showing this table.
Two tables are stored for each relay device. FIG. 3A shows a local management table 41 that stores data regarding LAN terminals connected to the LAN on the relay device side. That is, for example, if this table is stored in the relay device 35, the MAC address 411 and virtual sub-address (Sd) 412 of this local management table 41 are stored in the LAN terminal 31 (actual address) connected via the LAN 33. There are multiple M in
An AC address and a virtual sub-address are each registered in advance. FIG. 3(b) shows a remote management table 42 that stores data regarding LAN terminals or ISDN terminals connected to the LAN on the other side of the relay device. That is, for example, if this table is stored in the relay device 35, the MA of this remote management table 42 is
C address 421, ISDN number Dn 422, and subaddress (Sd) 423 include ISDN 36, LAN terminal 32 (actually there are multiple) connected via LAN 34, and ISDN terminal connected via ISDN 36. M regarding 38 (actually there are multiple)
AC address, ISDN number D that serves as the communication route (route)
n and a subaddress (Sd) are each registered in advance. In the case of a LAN terminal, the real MA is set to MAC address 421.
C address is stored as a virtual subaddress in subaddress (Sd) 423, while in the case of an ISDN terminal,
A virtual MAC address is stored in the MAC address 421, and a real subaddress is stored in the subaddress (Sd) 423.

[0026] Also, whether the remote terminal is a LAN terminal or an ISD
There is a flag 424 to distinguish whether it is an N terminal. When the flag stored in this flag 424 is 0, it indicates that the remote terminal is a LAN terminal, and therefore indicates that the MAC address 421 is a real MAC address and the subaddress 423 is a virtual subaddress. on the other hand,
When this flag is 1, it indicates that the remote terminal is an ISDN terminal, and therefore indicates that the MAC address 421 is a virtual MAC address and the subaddress 423 is a real subaddress.

FIG. 3(c) is a diagram showing the entry table 43 stored in each relay device. The relay device is LA
When communication between the N and the FMBS is requested, the DLCI, which is the data link identification number of the FMBS, is associated with the MAC address, as described later, and registered in the entry table 43 in FIG. 3(c).

FIGS. 4 and 5 are flowcharts illustrating the entry table registration procedure and the transmission signal sending procedure performed by the relay device. The flowchart shown in FIG.
1 to the ISDN terminal 38 along route b, the procedure for registering an entry table and sending a signal to the FMBS is shown. The number following S indicates the step number.

[S1] The relay device 35 receives an M from the LAN terminal 31 in which the MAC address of the communication partner should be written.
An AC frame (45 in FIG. 6, which will be described later) is received. [S2] Determine whether the received MAC frame is a frame that should be relayed to the ISDN 36. This determination is
Local management table 41 stored in relay device 35
[Figure 3(a)] shows the MAC in the received MAC frame.
This is done depending on whether the address is included (filtering). If it is included (registered) in the local management table 41, it is not a signal that should be sent to the ISDN 36, and the process proceeds to step S11, which will be described later.On the other hand, if it is not included (registered), the frame is It is determined that the signal should be relayed, and the process proceeds to step S3.

[S3] MA in received MAC frame
C address is registered in entry table 43 (entry)
Determine whether or not. That is, the received MA
It is determined whether a communication route (path) for relaying C frames has been established. If there is no entry,
Steps S4 to S8 are executed to secure a communication path for relaying the MAC frame and register it in the entry table 43. On the other hand, if an entry has been made, steps S4 to S8 are skipped and the process proceeds to step S9.

[S4] MAC address DA of communication partner
is registered in the remote management table 42. If it is not registered, it is determined that the terminal to be the communication partner does not exist and connection is impossible, and the process proceeds to step S11. On the other hand, if it is registered, the process proceeds to step S5.

[S5] Refer to the remote management table 42 to find a MAC address that matches the destination address DA, and find the ISDN of the destination corresponding to that MAC address.
The number Dn and subaddress Sd are detected.

[S6] ISD detected in step S5
Based on the N number Dn and subaddress Sd, the ISDN Q. Call setup is performed according to the G.93X procedure.

[S7] As a result of the call setting in step S6, F
Obtain the data link identification number DLCI of the MBS. [S8] Perform DLCI entry. That is, the DLCI obtained in step S7 is stored in the DLCI 431 of the entry table 43 [FIG. 3(c)], the destination address DA is stored in the remote MAC address 434, and the MAC address S of the source LAN terminal 31 is stored in the local MAC address 433.
A, conversion type 432, destination address DA is real M
0 for AC address, 1 for virtual MAC address
Register. The conversion type 432 copies the value of the flag 424 in the remote management table 42 corresponding to the MAC address in the MAC address 421 that matches the destination address DA in the remote management table 42 as is.

[S9] According to the conversion type 432 of the entry table 43, convert the MAC frame to the DLCI frame (
47) in FIG. 6, which will be described later, is created. [S10] The DLCI frame created in step S9 is sent to the FMBS 36.

[S11] The received MAC address is discarded.

The flowchart shown in FIG.
5 shows the procedure for registering an entry table and sending a signal to the LAN when communication is performed from the ISDN terminal 38 to the LAN terminal 31 along route b. The number following S indicates the step number.

Steps S21 to S27 are performed on the D channel (C
-PLANE), and steps S31 to S35 are the procedures when a data frame is received on the B channel (U-PLANE).

[S21] Receive the D channel signal from ISDN. [S22] It is determined whether the D channel signal received in step S21 includes a subaddress of the source. If there is no subaddress of the originator, the process proceeds to step S27, the call is disconnected, and the process returns to the READY state. On the other hand, if there is a subaddress of the sender, the process advances to step S23.

[S23] It is determined whether the subaddress of the source in the D channel signal received in step S21 is registered in the subaddress 423 of the remote management table 42. If registered, MAC address 4
The source address SA is read out from 21, and the process proceeds to the corresponding step S24. On the other hand, if it is not registered, the process proceeds to step S27.

[S24] A call is established and a DLCI is obtained. [S25] The destination sub-address in the D channel signal received in step S21 is stored in the local management table 41.
Search from the virtual sub-address 412 of MAC address 4
The destination address DA is read from 11.

[S26] Registration (entry) is performed in the entry table 43. That is, the DLCI acquired in step S24 is stored in the DLCI 431, the destination address DA read in step S25 is stored in the local MAC address 432, and the destination address DA read in step S25 is stored in the remote MAC address 434 in step S.
Register the source address DA read in step 23. Furthermore, the conversion type 432 indicates that the destination address DA is the real MAC.
If it is an address, register 0, if it is a virtual MAC address, register 1. Conversion type 432 is remote management table 4
2, the value of the flag 424 in the remote management table 42 corresponding to the MAC address in the MAC address 421 that matches the destination address DA is copied as is.

[S27] The call is disconnected and the process returns to the READY state.

Next, as mentioned above, the B channel (U-P
The procedure when a data frame is received in LANE) will be explained. In this embodiment, data transmission is performed on the B channel (U-PLANE).
) only.

[S31] A DLCI frame is received from ISDN.

[S32] DL received in step S31
The DLCI in the CI frame is D in the entry table 43.
It is determined whether or not it is registered in the LCI 431. If it is registered, the process advances to step S33; if it is not registered, the process advances to step S35.

[S33] A MAC frame (45 in FIG. 6) is created from the DLCI frame (47 in FIG. 6) according to the conversion type 432 of the entry table 43. [S34] The MAC frame created in step S33 is sent to the LAN 33.

[S35] Discard the DLCI frame and
Return to EADY state.

In this way, the relay device 35 is configured as shown in FIG. 3(a).
Address management, route control, and frame conversion can be performed by having static information as shown in FIG. 3(b) and dynamic information as shown in FIG. 3(c).

[0050] Note that in the relay device 35, the LAN terminal 3
1 to the LAN terminal 32 along route a, the MAC frame from the LAN 33 (45 in FIG.
) encapsulated frame (46 in Figure 6) is sent to FMBS
All you have to do is send it to 36.

In the above description, the relay operation in the relay device 35 was explained, but the relay operation in the relay device 37 is also the same as that in the relay device 35. Figure 6 shows the LA
FIG. 2 is a diagram showing frame formats on N and ISDN. There is one type of frame on the LAN, the MAC frame 45, but there are two types of frames on the ISDN, as shown at 46 and 47. 46 is a frame format when the remote terminal is a LAN terminal, and MAC frame 4
5 is encapsulated. 47 is the format of a DLCI frame when the remote terminal is an ISDN terminal, and compared to frame 46, it does not have a MAC header part.

FIG. 7 shows a frame on the LAN (45 in FIG. 6) and a frame on the ISDN (45 in FIG. 6) in the relay device.
6, 47) is a diagram showing a conversion pattern. Numbers 45 to 47 in the figure indicate frames 45 to 47 in FIG.

Patterns 51 and 52 are from LAN to ISD.
It shows conversion patterns in the N direction, pattern 51 is when the other party is a LAN terminal, pattern 52 is
This is the case when the other party is an ISDN terminal.

Patterns 53 and 54 are from ISDN to LA.
It shows conversion patterns in the N direction, pattern 53 is when the source is a LAN terminal, pattern 54 is
This is the case where the source is an ISDN terminal.

Here, patterns 51 and 53 are cases in which 0 is registered in the conversion type 432 of the entry table 43 in FIG. 3, and patterns 52 and 54 are cases in which 1 is registered in the conversion type 432 in the entry table 43 in FIG. This is the case if it is registered. In other words, if the conversion described above is divided into types, if the remote terminal is a LAN terminal (conversion type 0
) and when the remote terminal is an ISDN terminal (conversion type 1
), and to distinguish these conversion types, the conversion type 43 is displayed on the entry table 43.
2 is provided.

Next, an embodiment in which specific values are given to the above addresses will be described. Figure 8 shows LAN-FMBS
- shows a LAN interconnected network model; L
A LAN terminal 62, a LAN terminal 63, and a relay device (IWU) 64 are connected to the AN 61, and a LAN terminal 66 and a relay device (IWU) 67 are connected to the LAN 65. Relay device 6 is used for ISDN68 of FMBS system.
4 and 67 are connected, and an ISDN terminal 69 is also connected without going through a relay device. Each device is illustrated with its respective protocol stack. As can be seen from the illustrated protocol stack, each device commonly implements protocols above layer 2. Furthermore, the LAN terminal 62 is assigned a MAC address 111 and a virtual subaddress 01, and similarly, the LAN terminal 63
MAC address 222 and virtual subaddress 02,
The LAN terminal 66 has a MAC address 333 and virtual subaddress 03, and the ISDN terminal 69 has a subaddress 04.
and assigns a virtual MAC address 444. Further, the line between the relay device 64 and the ISDN 68 is assigned the ISDN number Dn1111, the line between the ISDN 68 and the ISDN terminal 69 is assigned the ISDN number Dn2222, and the line between the relay device 64 and the ISDN 68 is assigned the ISDN number Dn2222.
The line between 7 and ISDN68 has ISDN number Dn3.
Assign 333.

Based on the above address assignment, FIG.
The local management table and remote management table are registered in advance as shown in FIG. Table 71 is a table stored in relay device 64, 72 is a local management table, and 73 is a remote management table. Further, a table 74 is a table stored in the relay device 67, 75 is a local management table, and 76 is a remote management table.

[0058] Now, the LAN terminal 62 is connected to the LAN terminal 66,
A case where the LAN terminal 63 communicates with the ISDN terminal 69 at the same time will be described with reference to FIGS. 10 and 11 as well as FIGS. 8 and 9.

FIG. 10 is a diagram showing the route setting and frame conversion of the relay device at the time of call setting. In the figure, the numbers shown in the route column are the LAN terminals 62, 63, 66 and I of FIG.
This is the illustrated number of the SDN terminal 69.

FIG. 11 shows the entry table given specific numerical values, FIG. 11(a) shows the entry table stored in the relay device 64, and FIG. 11(b) shows the entry table stored in the relay device 6.
7 shows an entry table stored in FIG.

First, in the case 81 of the route from the LAN terminal 62 to the LAN terminal 66, the LAN terminal 62
sends a MAC frame with a MAC address of 333. In response to this, the relay device 64 determines whether the MAC address=333 is registered in the local management table 72. Since it is not registered, next refer to the remote management table 73.
MAC address registered in 3 = IS corresponding to 333
The DN number Dn=3333, subaddress=03, and flag=0 are read out, and a call is set up for the relay device 67 from these. As a result, the relay device 64 and the relay device 67 are
Having acquired LCI=54, the relay device 64 operates as shown in FIG. 11(a).
The relay device 67 makes an entry as in the Index 0 column of FIG. 11(b). When the call is established, relay device 64 sends a DLCI frame to relay device 67. The relay device 67 is
When receiving the LCI frame, it converts the DLCI frame into a MAC frame according to the entry table shown in FIG. 11(b), and sends the MAC frame with destination address DA=333 to the LAN terminal 66.

From the LAN terminal 66 shown in the case 82 to the LA
In the case of the route to the N terminal 62, the transmission is performed in a completely reverse procedure to the above case 81. LAN terminal 6 shown in case 83
3 to the ISDN terminal 69, the LAN terminal 63 has a MAC address with a virtual MAC address of 444.
Send a frame. In response to this, the relay device 64 determines whether MAC address=444 is registered in the local management table 72. Since it is not registered,
Next, referring to the remote management table 73, ISDN number Dn = 2222 corresponding to MAC address = 444 registered in the remote management table 73, sub address = 0.
4. Read the flag = 1, and from these read the ISDN terminal 6.
Call setup is performed for 9. As a result, the relay device 64
Obtain CI=89 and enter as in the Index 1 column of FIG. 11(a). Since the MAC frame is converted into a DLCI frame by the relay device 64 according to this conversion type, the ISDN terminal 69 can receive data without being aware of the type of the opposite terminal below the layer 3 level.

L from the ISDN terminal 69 shown in case 84
In the case of the route to AN terminal 63, ISDN terminal 69 makes a call to a remote terminal with ISDN number Dn=1111 and subaddress=02. When this call arrives, the relay device 64 obtains the MAC address = 222 of the local terminal to be relayed from the subaddress = 02 according to the local management table 72, and makes an entry as in the Index 1 column of Fig. 11(a). At this time, the conversion type is registered as type 1 by referring to the source subaddress=04 with the remote management table 73. Thereafter, in the information transfer phase, conversion between MAC frames and DLCI frames is performed according to the entry table of FIG. 11(a).

Next, a specific search method when referring to each of the above tables will be described. The relay device manages three tables: a local management table, a remote management table, and an entry table, but these tables are not always searched using one type of search key (hereinafter referred to as "key"). . For example, in the case of information retrieval regarding the entry table, the local M
Search for the AC address (when relaying from FMBS to LAN direction), or perform DLC using the remote MAC address as a key.
I (when relaying from LAN to FMBS).

Hashing is generally used as a method for extracting desired data from a table with a large amount of data.
An algorithm is used. This method uses one search key (
This is a method of finding the desired information from a key), and when searching a common table as described above, it required some ingenuity to be able to search from multiple keys. Therefore,
A method for searching a common table using multiple keys by extending the hash algorithm will be described below. In the following explanation, an entry table will be used as an example, but the above search method can also be applied to local management tables and remote management tables.

FIG. 12 is a diagram illustrating a method of searching an entry table using a plurality of keys. The common table 90, which is a hash table, corresponds to an entry table, and R
MAC indicates a remote MAC address, and LMAC indicates a local MAC address. The pointer table 91 is used when searching the entry table using the remote MAC address as a key, and the pointer table 92 is used when searching the entry table using the DLCI as the key.

First, the procedure for storing entry information in the common table 90 will be explained. Using the remote MAC address as a key (step S41), this remote MAC address (for example, 2) is converted by a hash function (step S42) to obtain the address P (for example, 2000) of the pointer table 91. If there is no conflict (confirm by comparing the remote MAC addresses), the address P is the first address P'' (
For example, 100) is stored. If there is a conflict, the address of the pointer table 90 is changed using the conventional chain method or the open address method, and the common table 9 is added thereto.
Stores the start address of the unstored portion of 0. Next, the entry information (DLCI
, local MAC address, translation type).

Furthermore, the DLCI of the entry information is used as a key (step S43), and this DLCI (for example, 1) is used as a key.
is converted by a hash function (step S44), and the address P' of the pointer table 92 (for example, 1000
). At this address P', pointer table 9
P'' (for example, 100) stored at address P of 1 is stored.

In this way, the value P'' of the pointer in the pointer table 91 of the related remote MAC address and the value P' of the pointer in the pointer table 92 of the DLCI
' By making them the same, the same entry information can be referenced from both the remote MAC address and DLCI.

Next, the remote MAC address and DLCI
The following describes the procedure for searching common entry information from and. In the case of a search from a remote MAC address, the address P (for example, 2000) of the pointer table 91 is searched from the remote MAC address (for example, 2) using a hash function.
get. Based on the address P'' (for example, 100) of the common table 90 stored in the address P of the pointer table 91, the common table 90 is referred to and entry information is obtained.

[0071] In the case of searching from DLCI, DLCI
(for example, 1), the address P' (for example, 1000) of the pointer table 92 is obtained by a hash function. The address P'' of the common table 90 stored at the address P' of the pointer table 92 (for example, 100
), the entry information is obtained by referring to the common table 90.

[0072] In the above, the case where there are two keys has been explained, but the above method can also be applied when there are multiple keys. According to the above-mentioned search method using a hash method using a plurality of keys, since a common table is used, there is no need to have a table for each key, and memory can be reduced. Therefore, the larger the size of the common table data, the greater the effect of this method.

Furthermore, when making an entry, the common table data only needs to be stored once, so the entry speed becomes faster. Furthermore, the occurrence of collision can be absorbed by the pointer table, and the conventional chain method or open address method can be applied.

[0074]

[Effects of the Invention] As explained above, in the present invention, the LAN
A MAC address and a virtual subaddress are assigned to a terminal, and a virtual MAC address and a subaddress are assigned to an ISDN terminal, so the relay device performs LAN communication based on the MAC address or subaddress specified as the communication partner address. and FMBS-based ISDN can be interconnected at layer 2, making it possible to transmit data by taking advantage of the high-speed characteristics of FMB frame relay.

[0075] Furthermore, in this interconnection, the relay device mutually converts the LAN frame format and the ISDN frame format depending on the route, that is, the ISDN communication path, so that the LAN terminal - FMB
In addition to connecting S-LAN terminals, LAN terminals - FM
Connection of BS-ISDN terminals can also be realized at the same time.

Furthermore, since this conversion uses a table that can be searched by a hash method that can be accessed using multiple search keys, the relay device between the LAN and FMBS can manage real addresses and virtual addresses using the same table.
Furthermore, the hashing method using multiple search keys enables address search and frame conversion with less storage capacity.

[Brief explanation of the drawing]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a LAN-FMBS network diagram.

FIG. 3 is a diagram showing a table stored in a relay device.

FIG. 4 is a diagram showing an entry table registration and transmission procedure to the FMBS during communication from the LAN to the FMBS.

FIG. 5 is a diagram showing an entry table registration and transmission procedure to the LAN during communication from the FMBS to the LAN.

FIG. 6 is a diagram showing frame formats on LAN and ISDN.

FIG. 7 is a diagram showing a frame conversion pattern.

FIG. 8 is a diagram showing a network model in which specific numerical values are assigned to addresses and the like.

FIG. 9 is a diagram showing a local management table and a remote management table based on specific numerical values.

FIG. 10 is a diagram showing route setting and frame conversion of a relay device at the time of call setting.

FIG. 11 is a diagram showing entry tables of two relay devices.

FIG. 12 is a diagram illustrating a method of searching an entry table using multiple keys.

FIG. 13 is a protocol stack diagram in a conventional FMBS frame relay.

FIG. 14 is a protocol stack diagram in conventional FMBS frame relay.

FIG. 15 is a protocol stack diagram of a conventional LAN terminal and an ISDN terminal.

[Explanation of symbols]

1, 2 LAN 3 FMBS type ISDN 4,5 LAN terminal 6 ISDN terminal 7, 8 Relay device

Claims (4)

[Claims] [Claim 1] LAN (1, 2) and FMBS system I
LAN-F for data communication by connecting with SDN (3)
In the MBS connection method, a LAN terminal (4, 5) connected to the LAN (1, 2) and assigned a MAC address and a virtual subaddress, and a LAN terminal (4, 5) connected to the ISDN (3) and assigned a virtual MAC address and a subaddress. and the ISDN terminal (6) assigned to the LAN (1, 2) and the FMBS ISD based on the MAC address or subaddress specified as the communication partner address.
A LAN-FMBS connection system characterized by having a relay device (7, 8) that interconnects N(3). 2. The relay device (7, 8) is connected to the LA
2. The LAN-FMBS connection system according to claim 1, wherein the frame format of the ISDN and the frame format of the ISDN are mutually converted depending on the route. 3. The relay device (7, 8) is connected to the LA
3. The LAN-FMBS connection system according to claim 2, further comprising a table for mutually converting the ISDN frame format and the ISDN frame format. 4. The LAN-FMBS connection system according to claim 3, wherein the table is searched by a hashing method that allows access using a plurality of search keys.