JP2002009774A - Network load distribution method and system in lan emulation environment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a system and a method that can relive a load of each BUS(Broadcast Unknown Server) by avoiding broadcast packets from intensively flowing to one BUS. SOLUTION: The broadcast unknown servers(BUS) are mounted on an ATM network in the case of communication between LAN emulation clients(LEC) and the BUS is assigned to each communication protocol used for the communication by each LAN emulation client.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a LAN emulation technology for connecting to an M network, and more particularly to a network load distribution technology for a LAN emulation environment.

[0002]

2. Description of the Related Art ATM (Asynchronous Transfer Mod)
e; Asynchronous transfer mode) existing LAN (L
ocal Area Network), the BU which is a server for broadcast
Prepare S (Broadcast and Unknown Server)
We are broadcasting. In the network environment setting system built in LAN emulation version 1 (ATM forum), one BUS
Is connected to the ATM network, and the client participating in the LAN emulation broadcasts the frame to be transmitted to the entire LAN emulation by the BUS.
The BUS has an ATM connection for broadcast transmission and relay for all clients in the LAN emulation. The BUS that has received the broadcast frame transmits the frame to all LAN emulation clients in the LAN emulation that have established an ATM connection for broadcast relay.

[0003]

SUMMARY OF THE INVENTION As described above, LA
In the N emulation environment, the broadcast unknown server (BUS) is an ELAN (Emulated LAN)
It is assigned to each.

[0004] Multicast (multicast)
For packets, Selective BUS (Selective BUS)
Became available in version 2 of LAN emulation, but all Broadcast packets of all protocols used in ELAN are
The data was intensively transmitted to one BUS, and the transfer processing was performed by the BUS. As a result, due to the load of a large amount of data,
Processing may not be able to keep up, and a failure such as packet delay / discard may occur.

As a technique related to a LAN emulation environment, for example, Japanese Patent Laid-Open Publication No. H11-46206 discloses a technique of distributing a BUS load and increasing
As a method to prevent the emulation function from deteriorating, each BU
S for each LAN emulation client (LE
C) is divided into a plurality of groups, each BUS is responsible for broadcasting the LECs in the same group, and all the LECs are broadcasted.
And a method of establishing a multicast relay ATM connection and transmitting a broadcast frame from the LEC of the same group to all LECs in the system.

Accordingly, the present invention has been made in view of the above problems, and an object of the present invention is to reduce the load on each BUS by preventing broadcast packets from being concentrated on one BUS. To provide a system and method.

[0007]

According to the present invention, a LAN emulation client (LAN emulation client) is provided.
For the communication between lation clients), the broadcast / unknown server (Broadc
AST and Unknown Server, referred to as “BUS”), and a separate BUS for each communication protocol communicated by each of the LAN emulation clients.
Is assigned.

[0008]

Embodiments of the present invention will be described. The present invention relates to a communication between LAN emulation clients (hereinafter referred to as "LEC") in an ATM LAN emulation network, wherein the ATM network includes a broadcast / unknown server.
rver, “BUS”), and the BUS is assigned to each communication protocol communicated by each LEC.

With this configuration, the load on each BUS is reduced by preventing broadcast packets from being concentrated on one BUS.

In the present invention, as a means for identifying a BUS, a LAN emulation address resolution protocol (LE_ARP) request message exchanged between the LEC and a LAN emulation server (hereinafter referred to as “LES”) is used. Expand,
The identification of the BUS (the request for acquiring the BUS ATM address and the value of the protocol type) is realized.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an embodiment of the present invention; FIGS. 1 to 3 are diagrams for explaining the configuration and operation of one embodiment of the present invention.

The ATM switch (X) 21 has a LAN emulation configuration server (LAN)
Emulation Configuration Server, referred to as “LECS”), LES, and BUS (1).

The ATM switch (Y) 22 has a BU
Only S (2) is mounted and the ATM switch (Z) 23
Is simply for relaying data.

A terminal (X) 11, a terminal (Y) 12, and a terminal (Z) 13 are connected to the ATM switches (X), (Y), and (Z), respectively. , LEC (X)-(Z) mounted network interface card ("NI
C ").

In the example shown in FIG. 1, the terminal (X) 11 has an Internet Protocol (Internet Protocol).
"IP") and Internetwork Packet eXchange, "I
PX ”), the terminal (Y) 12 is bound with IP and IPX, and the terminal (Z) 13 is bound with only IP.

The operation of one embodiment of the present invention will be described. One embodiment of the present invention reduces a load on each BUS by distributing broadcast packets concentrated on a single BUS by allocating a BUS for each protocol in communication between LECs in an ATM LAN emulation network environment. Things.

LES (LAN emulation server)
Now, as shown in FIG. 1, A of the BUS on the network
A BUS address management table (1) that associates a TM address with a protocol is provided.

Terminal (X) 11, terminal (Y) 12, terminal (Z) 13
A description will be given of an example in which communication is performed by LEC between the two.

First, a procedure for joining the LAN emulation network is usually performed in order for the LEC to start communication. The LEC first starts with a LAN emulation configuration server (LAN Emulation Configuration Server) that manages the configuration of the LAN emulation.
Server; “LECS”), establish a VC (virtual connection), send a configuration request (LEConfigure Request) using the VC,
Emulated LAN (Emul)
ated LAN, called "ELAN")
The ATM address of S is obtained (see (2) in FIG. 1).

Next, a VC is established with the LES based on the ATM address (see (3) in FIG. 1).

After that, the LEC executes a LAN emulation ARP (LE_ARP) to open a VC with the BUS.
The request sends a BUS ATM address resolution request to the LES. However, at this time, the LE_ARP request is not extended (see (4) in FIG. 1).

The LES that has received the request message sends B
Default BUS from US address management table
The ATM address of (1) is unconditionally returned to the LEC (see (5) of FIG. 1).

The LEC that has acquired the default BUS ATM address establishes a VC with BUS (1) based on this address (see (6) in FIG. 1).

The LEC has now completed the subscription procedure and is now in a state (OPERATIONAL) where communication can be performed.

Next, the communication procedure of the terminal (Y) 12 using IPX will be described.

In the terminal (Y) 12, each time the LEC receives transmission data from the upper layer protocol, the LEC
22.3 (Ethernet (registered trademark)) header is analyzed. FIG. 4A shows a part of a LAN emulation frame format for IEEE802.3. A 2-byte LE header is provided before the destination MAC (Media Access Control) address field.

In this embodiment, LLC (Logical Link C)
ontrol) shall not be encapsulated (LLC / SNAP
Not encapsulated).

The method of analyzing the header is as follows. First, it is determined whether or not the destination address field is for broadcast (all destination bits are on, see FIG. 4B).

If the destination is broadcast, the type field is checked to determine the type of protocol. In the case of this embodiment,
In this field, a protocol number indicating IPX (0x81
37) is stored. In the case of IP, a protocol number (0x0800) is stored (see FIG. 4C).

The LEC uses LE_ARP (LAN Emulation Address R) to resolve the BUS address dedicated to IPX.
esolution Protocol) request to the LES. In FIG. 2, the LE_ARP request is the L of the terminal (Y) 12.
It is transmitted from the EC to the LES of the ATM switch 22 ((1) and (2) in FIG. 2).

At this time, the LE_ARP request includes a type (Type) indicating a request to acquire an ATM address of a BUS dedicated to IPX and a value (Type of Length) indicating its protocol.
th Value, “TLV”) is added (FIG. 4)
(D)).

The LES that receives the LE_ARP request from the LEC recognizes that the request is an address analysis request of the BUS for each protocol by confirming that the TLV is added, and checks the BUS address management table of its own device. Make a reference.

The LES detects the ATM address of the BUS (2) dedicated to IPX registered in the BUS address management table in advance, and, as a response to the LE_ARP request, the type (Type) indicating the return of the ATM address of the BUS by protocol. The ATM address of the BUS is L
Return to EC ((3) in FIG. 2).

The LEC receiving the response is the ATM
A VC is opened based on the address ((4) in FIG. 2).
Transfer to US (2) ((5) in FIG. 2).

Finally, every time there is a data transmission request of the upper protocol, the LEC (Y) 12 should transmit the data by determining whether the destination of the data is a broadcast packet and further which protocol it is. BUS
To determine.

At this time, if the corresponding BUS is not found, the LES returns the default BUS (1) ATM address.

When the LEC (Y) 12 transmits an IP broadcast packet, as in the case of the IPX, the LEC (Y) 12 inquires the LES as to which BUS to transfer. Has no information about the IP, the LES returns the default BUS (1) ATM address.

In the LEC receiving this response,
An IP broadcast packet is transmitted to the default BUS (1) ((6) in FIG. 2). As described above, in the present embodiment, an IP broadcast packet, which is a protocol without a dedicated BUS, is transmitted using BUS (1).

As a result, the IP broadcast packet and the IPX broadcast packet are shown in FIG.
As shown by a solid line and a broken line, data is distributed via BUS (1) and BUS (2) corresponding to each communication protocol.

When the LEC of the present invention subscribes to a normal LAN emulation environment, it performs a normal subscribing operation, and all broadcast packets are transmitted.
It will be sent to a single BUS. At this time, the TLV added to the LE_ARP request is discarded without being interpreted by the normal LES. Therefore, no problem occurs.

[0041]

As described above, according to the present invention,
This has the effect of reducing the load of intensive broadcast packets on one BUS and preventing delays and discards of data transfer in network communication.

The reason is that, in the present invention, a plurality of BUSs are mounted on a network, and the BUS is assigned to each protocol.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining an embodiment of the present invention.

FIG. 2 is a diagram for explaining an embodiment of the present invention.

FIG. 3 is a diagram for explaining an embodiment of the present invention.

FIG. 4 is a diagram for explaining a header format and an extension of an LE_ARP request in one embodiment of the present invention.

[Explanation of symbols]

 11-13 Terminal 21-23 ATM switch

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Masahiro Tsuda 3-18-21 Shibaura, Minato-ku, Tokyo NEC Engineering F-term (reference) 5K030 HA10 HB16 HB18 HC15 HD09 KA01 KA05 LD02 LE03

Claims (10)

[Claims] 1. A LAN emulation client (LA)
ATM (As) for communication between N Emulation Clients
(Broadcast and Unknown server)
2. A method of distributing network load in a LAN emulation environment, comprising: providing a plurality of known servers (referred to as "BUS"); and assigning a BUS to each protocol used for communication between the LAN emulation clients. 2. A LAN emulation server (LAN emulation server) holding a management table in which a bus ATM address and a protocol on a network are associated with each other.
rver), the LAN emulation address resolution protocol (LAN Emulation Address Resolut) transmitted from the LAN emulation client.
(Ion Protocol) request message, a type indicating acquisition of a BUS ATM address for each protocol and a value indicating a protocol are added, and the LAN emulation server that has received the LAN emulation / address resolution protocol request refers to the management table. And obtains an ATM address of a BUS of a designated protocol, and in response to the LAN emulation / address resolution protocol request, a response message transmitted from the LAN emulation server to the LAN emulation client includes a BU for each protocol.
Type indicating return of ATM address of S and AT of BUS
2. The method according to claim 1, wherein an M address is added. 3. The method according to claim 1, wherein a broadcast packet of a protocol having no dedicated BUS is transmitted using a default BUS. 4. The LAN emulation client, every time there is a data transmission request from a higher-level protocol, determines whether the destination of the data is a broadcast packet or to which protocol, and determines a BUS to be transmitted. At this time, if the corresponding BUS is not found, the LAN emulation server sets the default B
4. The LAN emulation environment according to claim 1, wherein the LAN emulation client notifies the LAN emulation client of the US, and the LAN emulation client transmits a broadcast packet using the default BUS. 5. Network load balancing method. 5. The LAN emulation client comprises an Internet Protocol ("IP"),
Or transmitting a LAN emulation address resolution protocol request to the LAN emulation server to resolve a BUS address for an internetwork packet exchange (referred to as "IPX"), wherein the LAN emulation address is transmitted. Adding, to the resolution protocol request, information indicating a request to acquire an ATM address of a BUS for IP or IPX; and a LAN emulation server receiving the request to which the information has been added, comprising: It refers to the management table held by the server itself, detects the ATM address of the BUS dedicated to IP or IPX registered in advance in the management table, and uses the ATM address of the BUS as a response,
Returning the LAN emulation client to the LAN emulation client, and returning a default BUS ATM address to the LAN emulation client if the dedicated BUS ATM address does not exist in the management table; and the LAN emulation client receiving the response. Establishing a virtual connection (VC) based on the returned ATM address, and thereafter, transferring an IP or IPX broadcast packet to a BUS of a corresponding protocol, respectively. 3. The network load distribution method for a LAN emulation environment according to claim 2, wherein 6. A LAN emulation system, comprising: a LAN emulation client;
on Client), ATM (Asynchronous)
Transfer Mode) network with a broadcast and unknown server
ver, “BUS”), and the LAN emulation server
A management table in which a US ATM address and a protocol are associated with each other, wherein the LAN emulation client acquires the BUS ATM address for each communication protocol by the LA
N LAN emulation server, the LAN emulation server having received a request from the LAN emulation client refers to the management table, and refers to the management table to check the BUS AT for each communication protocol.
Means for returning a type indicating the return of the M address and an ATM address of the BUS to the LAN emulation client, wherein a BUS is individually assigned for each communication protocol between the LAN emulation clients. Network load balancing system. 7. A LAN emulation address resolution protocol (LAN Emulation Address Resolution) transmitted from the LAN emulation client.
Protocol; LE_ARP) request message, a type indicating acquisition of a BUS ATM address for each protocol and a value indicating a protocol indicating the protocol are added. The LAN emulation server receiving the LAN emulation / address resolution protocol request, With reference to the management table, an ATM address of the BUS of the designated protocol is acquired, and the response message of the address resolution protocol request transmitted from the LAN emulation server to the LAN emulation client includes a B for each protocol.
Type indicating return of US ATM address and BUS A
7. The network load balancing system according to claim 6, wherein the network load is returned after adding a TM address. 8. The network load distribution system in a LAN emulation environment according to claim 6, wherein a broadcast packet of a protocol having no dedicated BUS is transmitted using a default BUS. 9. The LAN emulation client, every time there is a data transmission request from a higher-level protocol, determines whether the destination of the data is a broadcast packet or to which protocol, and determines a BUS to be transmitted. At that time, if the corresponding BUS is not found,
9. The LAN emulation server according to claim 6, wherein a default BUS ATM address is returned from the LAN emulation server, and the LAN emulation client transmits a broadcast packet using a default BUS. Network load distribution system for LAN emulation environment. 10. The LAN emulation client may include a LAN emulation address for resolving a BUS address for Internet Protocol ("IP") or internetwork packet exchange ("IPX"). A resolution protocol request is transmitted to the LAN emulation server. At this time, the LAN emulation address resolution protocol request is added with information indicating a request to acquire an ATM address of a BUS dedicated to IP or IPX, and the information is added. Upon receiving the LAN emulation / address resolution protocol request, the LAN emulation server recognizes the analysis as the ATM address analysis of the BUS for each protocol, refers to the management table held by its own server, and Registered in advance in the management table
Alternatively, the ATM address of the BUS dedicated to IPX is detected, and the ATM address of the BUS is returned to the LAN emulation client as a response.
Means for returning a default BUS ATM address to the LAN emulation client when the dedicated BUS ATM address does not exist in the management table, wherein the LAN emulation client having received the response is based on the ATM address. 7. A virtual connection (VC) is opened, and thereafter, an IP or IPX broadcast packet is transferred to a BUS of a corresponding protocol, respectively.
A network load distribution system for a LAN emulation environment as described in the above.