KR100264349B1 - How to handle B.U.S in LAN emulation - Google Patents

Abstract

PURPOSE: A BUS(Broadcasting and Unknown Server) processing method in LAN emulation is provided to improve the performance of system by eliminating procedures in a system consumed for broadcasting and unnecessary data in a terminal. CONSTITUTION: Data transmitted to BUS while a source LEC(LAN Emulation Client) waits for a response from LES(LAN Emulation Server) are stored in a BUS buffer by a BUS manager. When an output port/VPI/VCI is a hold-state, all inputted data are temporarily stored in the BUS buffer. The LES acquires an ATM address of the opposite LEC, sets Multicast Forward VCC of BUS connected to the opposite LEC, transfers all data stored in the buffer to the opposite LEC, and transmits an LE-ARP.resp to the source LEC. The source LEC stops transmitting the data and sends a flash request frame, and accordingly the opposite LEC sends a flash response frame to the LES and sends them to the source LEC again. The source LEC restarts to transmit data through Data Direct VCC.

Description

How to handle B.U.S in LAN emulation

The present invention relates to a LAN emulation that connects an Asynchronous Transfer Mode (ATM) and a Local Area Network (LAN). In particular, the signal processing of the BUS (Broadcasting and Unknown Server) constituting the LAN emulation is more briefly described. It relates to a bus processing method in LAN emulation.

Asynchronous Transfer Mode (ATM) is a key technology for efficiently transmitting B-ISDN, which is to transmit voice, data, and video traffic efficiently through a single network regardless of information traffic characteristics. This was adopted.

These ATMs support flexible and efficient data transmission using dynamic bandwidth allocation and point-to-point connections. These ATMs are strengthening their position as next-generation networks, and their projects are actively promoted at national and international levels. There is.

On the other hand, the emerging broadband multimedia applications are the main factors driving the broadband integrated communication network. However, the development of ATM specific application programming interface (API) and higher application software using the same have not been completed. Data communication applications and protocols are still the main services of ATM networks.

In addition, by interworking existing LANs such as Ethernet or Token Ring, which form the infrastructure of current data communication with ATM network, application of existing LAN in mixed environment of ATM network and existing LAN Local Area Network (Emulation) Emulation has been proposed to provide natural support for mobile devices, that is, to accommodate existing Transmission Control Protocol / Internet Protocol (TCP / IP) services in existing ATM networks.

This local area network (LAN) emulation provides a Media Access Control (MAC) layer service that emulates existing connectionless LAN services in an ATM network so that a vast amount of existing LAN application software can be used in an ATM network. .

The LAN emulation described above forms an emulated network, which is a logical overlay network, on the ATM network. The LAN emulation service is a set of LAN emulation clients (LECs) installed in each end system of the emulated LAN, and three logical Service elements. These three logical service elements are called LAN Emulation Construction Server (LECS), LAN Emulation Server (LES), and Broadcast and Unknown Server (BUS), and LEC uses the services provided by these three servers. It supports interworking with existing LAN and ATM network and transparent communication between LAN applications in ATM network.

In addition, each ATM end system constituting the emulated LAN has an LEC, and three logical LE service elements may be centrally implemented in one physical network entity or distributed in multiple physical network entities. . The LECs in each end system provide existing LAN services to upper-tier applications by utilizing the services provided by the three logical LESs.These LAN emulation services enable ATM end systems and existing LAN terminations over ATM networks. A virtual logical emulated LAN consisting of the system is formed.

FIG. 1 is a diagram for explaining data transmission between LECs, LESs, BUSs, and LECs through three transmission paths, and LESs and BUSs.

The LEC is a component located in the end system that uses the services of the LES to provide upper layer applications with control for data forwarding, address resolution and other LAN emulation services. In order to communicate with other hosts on the emulated LAN, the upper layer application forwards the frame to be sent to the LEC as if it were using the MAC service on the existing LAN. In addition, the LEC uses the ATM Ad Apartment Layer (AAL) -5 service to communicate with the remote LEC, and the UNI signaling control to set and release the VCC required for such communication.

The LES is the server responsible for address resolution of the emulated LAN. There is one LES for each emulated LAN. To register for an emulated LAN, the LEC provides its LES with its own address information (ATM address, MAC address). . The LES maintains the ATM address information of the registered LEC. When the source LEC sends an LE-ARP (Address Resolution Protocol) request to find the ATM address of the destination LEC to which the data is to be communicated, the LES processes it. In addition, the LES responds directly to the LEC's request for address resolution if it knows the ATM address corresponding to the destination MAC address specified by the LE-ARP request; otherwise it finds it from other LECs and responds.

BUS is a server that supports broadcast and forwards unknown frames to all LECs on the emulated LAN. This BUS has two functions. The first function is to support ATM with the broadcast function provided by the LAN using the shared media, and transmits the MAC address data interpreted by LAN emulation to the corresponding LEC. The second function is used to send unicast traffic while the LEC participates in the address resolution process.

On the other hand, when the BUS transmits unicast traffic while the LEC participates in the address resolution process, first, when the LEC transmits a frame to another LEC whose address is not known, address resolution and connection establishment with the destination LEC are necessary. This allows simulating that the connectionless service on the LAN initiates data transfer without delay for connection establishment by allowing all LECs to start the transmission without waiting for it to finish, and the LES is ultimately unable to resolve ATM addresses. In the case of LECs (for example, the host of an existing LAN), this is for transmitting data. Ultimately, all LECs on an emulated LAN must establish a point-to-point connection with the BUS to participate in the emulated LAN.

On the other hand, and as described above, the path for transmitting data in the emulated LAN is used for data transmission between LECs is used for Data Direct virtual channel connection (VCC) and data transmission between LEC and BUS. There are three types of Multicast Send VCCs and Multicast Forward VCCs. In addition, the data transmission step is a step of transmitting an encapsulated LE-SDU (Service Data Unit) in the form of an AAL-5 frame that the LEC can transmit, and accepting the AAL-5 frame and accepting the decapsulation.

In other words, there are two types of frames transmitted by LAN emulation, unicast frame and broadcast frame. In the case of unicast frame, LEC sets Data Direct VCC to ATM address of destination LEC and transmits the frame.

In addition, as described above, when attempting to unicast data to an LEC that does not know an ATM address, the LEC first sends an address resolution request frame (LE-ARP.req) to the LES and sends a response (LE-ARP.resp). While waiting for a response (LE-ARP. Resp) to come, the LEC may start the transmission of a data frame over the BUS. On the other hand, after that, when a response to the LE-ARP (LE-ARP. Resp) waited from the LES comes, the LEC sets up a Data Direct VCC with a destination LEC and starts data frame transmission through this connection.

That is, while LEC sends an address resolution request frame (LE-ARP. Req) to LES and waits for a response (LE-ARP. Resp), the LEC may start transmitting the data frame over the BUS. Since they are transmitted through two paths, as shown in FIG. 1, a flush protocol for maintaining the order of data frames, that is, a flush request frame should be used. In addition, when a response (LE-ARP. Resp) arrives, the LEC stops data transmission and transmits a flush request frame through the Multicast Send VCC once it is transmitting via BUS while waiting for a response.

Accordingly, it is learned that data frames are no longer transmitted to the counterpart LEC receiving the flush request frame through the BUS, and data frames to be transmitted later will be transmitted through the Data Direct VCC. The LEC then sends a flush response frame to the LES, which sends it back to the LEC that sent the flush request frame.

Accordingly, the LEC receiving the flush response frame has confirmed that the other LEC has received the data frame transmitted through the BUS, and from this time, data transmission is resumed through the Data Direct VCC.

However, in the above-described method, when the BUS does not know the ATM address of the LEC to transmit data, the network resources are used more than necessary because the data is transmitted to all LECs, and the processing procedure is very complicated. There was a problem such as difficulty in constructing.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to reduce the increase in network usage due to duplication of data transmission of BUS in processing LAN emulation and to simplify the complicated processing. To provide a way to handle BUS in a LAN emulation.

According to a preferred embodiment of the present invention for achieving the above object, in the method for processing BUS (Broadcasting and Unknown Server) processing in LAN emulation, (A) the source LAN Emulation Client (LEC) is LES Storing the data transferred to the BUS in a predetermined buffer while waiting for a response to the LE-ARP from the LAN Emulation Server; (B) Search the input port / VPI / VCI and search the status of the output port / VPI / VCI to be connected through it.If the output port / VPI / VCI is 'hold', all the input data is temporarily stored in the BUS buffer. And (c) after step (b), the LES recognizes the ATM address of the counterpart LEC, sets the multicast forward VCC of the bus connected to the counterpart LEC, and transfers all data stored in the buffer to the counterpart LEC. Sending an LE-ARP.resp response to the source LEC; (D) The source LEC once stops transmitting data and transmits a flush request frame through the Multicast Send VCC of the BUS, whereby the counterpart LEC transmits a flush response frame to the LES, and the LES flushes the flush request frame again. Sending to the source LEC that sent the message; (E) the source LEC receiving the flush response frame confirms that the other LEC has received the data frame transmitted through the BUS, and then resumes data transmission through the Data Direct VCC.

1 is a view showing the operation of the conventional LAN emulation,

2 is a view for explaining the operation of the LAN emulation according to the BUS processing method in the LAN emulation according to the present invention;

3 is a block diagram illustrating a BUS processing apparatus for executing a BUS processing method in LAN emulation according to the present invention;

<Description of the code | symbol about the principal part of drawing>

10: LAN emulation database section

20: LES controller 30: access controller

40: BUS controller 50: BUS receiver

60: BUS manager 65: broadcasting table

70: BUS buffer 80: BUS transmitter

90: AAL-5 interface

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a view for explaining the operation of the LAN emulation by the BUS processing method according to the present invention, Figure 3 is a block diagram showing an apparatus for executing a BUS processing method in the LAN emulation according to the present invention.

First, according to the present invention, it is assumed that LAN emulation servers exist on the same system for convenience, and the LAN emulation server is composed of LECS, LES, and BUS as described above.

As shown in FIG. 3, the BUS processing apparatus for implementing the present invention includes a LAN emulation database unit 10, a LES controller 20, a connection controller 30, a BUS controller 40, and a BUS receiver. And 50, the BUS manager 60, the BUS buffer 70, the BUS transmitter 80, and the AAL-5 interface unit 90.

The LES controller 20 and the BUS controller 40, via the connection controller 30, control direct VCC from LEC to LES, bidirectional Control Distribute VCC between LES and LEC, multicast send VCC from LEC to BUS, and BUS and LEC Bidirectional Multicast Forward Four types of data channels can be set.

Meanwhile, the Control Direct VCC among the data channels that the LES controller 20 and the BUS controller 40 can set through the access controller 30 is for the LEC to request LAN emulation information to the LES, and the Control Distribute VCC is for It is used to transmit control information to all the LECs registered in the LAN emulation database unit 10.

In addition, Multicast Send VCC is used when LES transmits information to all LECs via BUS, and Multicast Forward VCC is used by BUS to deliver data to all LECs.

Meanwhile, the LAN emulation database unit 10 stores the information of the connected channel and the address of the LEC and the VPI / VCI information connected to the LEC, which are provided through the access controller 30 and the LES controller 20.

When data is transmitted from the LEC to the Control Direct VCC channel through the AAL-5 interface unit 90, the LES controller 20 receives and analyzes the transmitted data and determines that the data needs to be broadcast. 50).

In addition, the BUS controller 40 transmits data provided from the LEC through the AAL-5 interface unit 90 to the BUS receiver 50. All data input to the BUS controller 40 must be originally broadcast. to be.

All data transmitted to the BUS receiver 50 is provided to the BUS manager 60.

On the other hand, according to the present invention, the BUS has a constant buffer, that is, the BUS buffer 70, which temporarily transmits data that has been broadcast to all LECs while the information of the other LEC, i.e., the ATM address, is unknown. If the LEC information on the other side of the data is found while storing the data, then the temporarily stored data is transmitted to the corresponding LEC to increase the efficiency of the network. The data is stored and output under the control of the BUS manager 60.

In addition, the BUS manager 60 analyzes the data transmitted from the BUS receiver 50 to indicate what state is in the broadcasting table 65. There are three states, the output port of the broadcasting table 65. Is written on. As shown in FIG. 3, 'all' indicates information to be broadcast to all LECs, that is, all relative LECs, and 'hold' indicates that information on the LEC is being searched. In this case, LEC The data transmitted from is temporarily stored in the BUS buffer 70, and after detecting the information of the opposite LEC, the data is transmitted only to the corresponding LEC. If the value of 'VPI / VCI' is determined as '2/0/105', the information of the other LEC is already obtained. In this case, the data is transmitted immediately to the corresponding LEC.

Hereinafter, the present invention will be described in detail with reference to FIG. 2.

First, data transferred to the BUS while the LEC waits for a response from the LES to the LE-ARP is stored by the BUS manager 60 in a separate memory of the BUS, that is, the BUS buffer 70.

The BUS manager 60 searches for the input port / VPI / VCI of the built-in broadcasting table 65 to search the state of the output port / VPI / VCI to be connected. As described above, when the output port / VPI / VCI is 'hold', the bus manager 60 is in a state where the LES is searching for the ATM address of the counterpart LEC. Temporarily save all.

Then, when the LES knows the ATM address of the other LEC, it sets the Multicast Forward VCC of the bus connected to the other LEC at the output port of the broadcasting table 65, and transfers all the data stored in the buffer 65 to the other LEC. The LE-ARP.resp response is sent to the source LEC and processed in the same manner as in the conventional procedure.

On the other hand, the source LEC once stops transmitting data and transmits a flush request frame through the Multicast Send VCC of the BUS. The other LEC receiving the flush request frame through the BUS recognizes that the data frame is no longer transmitted through the BUS, and that the frame to be transmitted later will be transmitted through the Data Direct VCC.

Then, the flush response frame is transmitted to the LES, and the LES transmits the flush response frame back to the LEC which sent the flush request frame. The LEC, which received the flush response frame, confirmed that the other LEC received all the data frames transmitted through the bus. From this time, data transmission is resumed through the Data Direct VCC.

That is, the present invention, in the LEC, the buffer is not transmitted until the LE-ARP.resp response is received to manage it or delay the generation of the data, and the buffer in the BUS simplifies the above procedure. It is to reduce network waste.

As described above, when the LAN emulation server is configured, the present invention can reduce the network occupancy of the broadcasted data as compared to the prior art, and continuously remove unnecessary data from the processing procedures and terminals of the system consumed for broadcasting. This has the effect of improving the performance of the system.

Claims (1)

In the method for processing BUS (Broadcasting and Unknown Server) processing in LAN emulation, (A) storing the data transferred to the BUS in a predetermined buffer while the source LAN Emulation Client (LEC) waits for a response from the LAN Emulation Server (LES) to the LE-ARP; (B) Search the input port / VPI / VCI and search the status of the output port / VPI / VCI to be connected through it.If the output port / VPI / VCI is 'hold', all the input data is temporarily stored in the BUS buffer. Storing; (C) After the step (b), the LES recognizes the ATM address of the counterpart LEC, sets the multicast forward VCC of the bus connected to the counterpart LEC, transfers all the data stored in the buffer to the counterpart LEC, and sends the LE-ARP. sending a .resp response to the source LEC; (D) The source LEC once stops transmitting data and transmits a flush request frame through the Multicast Send VCC of the BUS, whereby the counterpart LEC transmits a flush response frame to the LES, and the LES flushes the flush request frame again. Sending to the source LEC that sent the message; (E) BUS processing in the LAN emulation including the step of the source LEC receiving the flush response frame confirms that the other LEC has received the data frame transmitted through the BUS, and then resumes data transmission through the Data Direct VCC. Way.