JP3529329B2 - Network load distribution method and system in LAN emulation environment - Google Patents

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 particularly to a network load balancing technology for a LAN emulation environment.

[0002]

2. Description of the Related Art ATM (Asynchronous Transfer Mod)
e; Asynchronous transfer mode) network with existing LAN (L
In an environment that emulates an ocal area network (BU), which is a broadcast (broadcast) server
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
To connect to the ATM network and participate in the LAN emulation, the client who wants to broadcast and transmit the entire LAN emulation has the above BUS.
The BUS has ATM connections for broadcast transmission and relay to 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 ATM connections for broadcast relay.

[0003]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention As mentioned above, LA
In the N emulation environment, the broadcast unknown server (BUS) is an ELAN (Emulated LAN).
It is assigned to each.

Multicast (Selective Broadcast)
For packets, selective BUS (Selective BUS)
Became available with version 2 of the LAN emulation, but all protocol Broadcast packets used in the ELAN are
It was sent centrally to one BUS and was transferred by the BUS. As a result, because of the load of a large amount of data,
Processing may not catch up, and failures such as packet delay / drop may occur.

As a technique related to a LAN emulation environment, for example, Japanese Patent Laid-Open No. 11-46206 discloses a LAN for the increase of LEC by distributing the load of BUS.
As a method of preventing the emulation function from degrading, each BU
LAN emulation client (LE
C) is divided into a plurality of groups, each BUS shares the LEC broadcast within the same group, and all LECs
And a multicast relay ATM connection is established so that a broadcast frame from the LEC of the same group is transmitted to all LECs in the system.

Therefore, the present invention has been made in view of the above problems, and an object thereof is to reduce the load on each BUS by preventing broadcast packets from flowing in a single BUS. System and method.

[0007]

SUMMARY OF THE INVENTION The present invention for achieving the above object includes a LAN emulation client (LAN Emu
For communication between relation clients, the broadcast unknown server (Broadcas
t and Unknown Server, and mounting a plurality of) of "BUS", the each communication protocol communicated by the LAN emulation client, which assign BUS individually, on the network of the BUS
Management table that associates ATM addresses with protocols
LAN emulation server ( LAN Emu
lation Server ) to the LAN emulation
LAN emulation sent from the client
Address resolution protocol ( LAN Emulation Addres
s ResolutionProtocol ) The request message
Thailand showing acquisition of BUS ATM address by rotocol
And a value indicating the protocol are added to the LAN emulation.
Address resolution protocol request
The acquired LAN emulation server is
Refer to Bull, AT of BUS of specified protocol
M address is acquired and the LAN emulation
In response to the dress resolution protocol request, the LAN
From the emulation server to the LAN emulation
Response message sent to the client
Indicates return of BUS ATM address by protocol.
Type and BUS ATM address are added .

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described. The present invention relates to communication between LAN emulation clients (LAN Emulation Clients, referred to as “LECs”) in an ATM LAN emulation network by using a broadcast unknown server (Broadcast and Unknown Se).
rver, referred to as "BUS"), and the BUS is assigned to each communication protocol communicated by each LEC.

With this configuration, the load of each BUS is reduced by preventing broadcast packets from flowing in one BUS.

In the present invention, as a means for identifying the BUS, a LAN emulation address resolution protocol (LE_ARP) request message exchanged between the LEC and the LAN emulation server (LAN Emulation Server, called "LES") is transmitted. Extended,
The identification of the BUS (the request for acquiring the ATM address of the BUS and the value of the protocol type) is realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings in order to explain the embodiment of the present invention in more detail. 1 to 3 are views for explaining the configuration and operation of one embodiment of the present invention, respectively.

The ATM switch (X) 21 has a LAN emulation configuration server (LAN
Emulation Configuration Server, "LECS"), LES, and BUS (1) are implemented.

The ATM switch (Y) 22 has a BU
Only S (2) is installed, and ATM switch (Z) 23
Is just 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, and each of the terminals 11 to 13 is connected. , LEC (X) to (Z) are installed on the network interface card ("NI
(Referred to as “C”) is implemented.

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

The operation of one embodiment of the present invention will be described. According to an embodiment of the present invention, in the inter-LEC communication in the ATM LAN emulation network environment, by assigning a BUS for each protocol, the broadcast packets concentrated in a single BUS are dispersed to reduce the load on each BUS. It is a thing.

LES (LAN emulation server)
Then, as shown in Fig. 1, A of BUS on the network
A BUS address management table (1) that associates TM addresses with protocols is provided.

Terminal (X) 11, terminal (Y) 12, terminal (Z) 13
An example will be described in which communication is performed between LECs.

First, in order for the LEC to start communication, a procedure for joining the LAN emulation network is usually performed. The LEC is a LAN emulation configuration server (LAN Emulation Configuration Server) that manages the LAN emulation configuration.
Server; "LECS") and VC (virtual connection) is opened, and the configuration request (LEConfigure Request) is transmitted using the VC,
The emulated LAN (Emul) you want to join
LE that manages ated LAN and "ELAN")
The ATM address of S is acquired (see (2) in FIG. 1).

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

Thereafter, the LEC establishes a VC with the BUS by LAN emulation ARP (LE_ARP).
Send a BUS ATM address resolution request by request to LES. However, at this time, the LE_ARP request is not expanded (see (4) in FIG. 1).

The LES receiving the request message is B
From the US address management table, the default BUS
The ATM address in (1) is unconditionally returned to the LEC (see (5) in FIG. 1).

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

At this point, the LEC has completed the joining procedure and is now in a state of being able to communicate (OPERATIONAL).

Next, an IPX communication procedure in the terminal (Y) 12 will be described.

In the terminal (Y) 12, the LEC receives the transmission data from the upper layer protocol, the IEEE 8
The header of 02.3 (Ethernet (registered trademark)) is analyzed. FIG. 4A shows a part of the 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) Not 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 the destination bits are on, see FIG. 4B).

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

LEC uses LE_ARP (LAN Emulation Address R) to resolve the BUS address dedicated to IPX.
esolution Protocol) request to LES. In FIG. 2, the LE_ARP request is 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, in the LE_ARP request, the type (Type) indicating the acquisition request of the ATM address of the BUS dedicated to IPX and the value (Type of Leng) indicating the protocol thereof.
th Value, "TLV") is added (Fig. 4
(See (d)).

The LES, which has received this LE_ARP request from the LEC, recognizes that it is the address analysis request of the BUS for each protocol by confirming that the TLV is added, and recognizes that it is 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 which is registered in advance in the BUS address management table, and as a response of the LE_ARP request, the type (Type) indicating the return of the ATM address of the BUS for each protocol. The ATM address of the BUS is L
Return to EC ((3) in Figure 2).

Upon receiving the response, the LEC sends the ATM
A VC is opened based on the address ((4) in FIG. 2), and thereafter, for the IPX broadcast packet, B
Transfer to US (2) ((5) in FIG. 2).

Finally, the LEC (Y) 12 should transmit each time there is a data transmission request of the upper layer protocol by judging whether the destination of the data is a broadcast packet or which protocol. BUS
To decide.

At this time, when the corresponding BUS cannot be found, the LES returns the default BUS (1) ATM address.

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

At the LEC which receives this response,
An IP broadcast packet is transmitted to the default BUS (1) ((6) in FIG. 2). As described above, in this 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 the solid line and the broken line, the data is distributed via BUS (1) and BUS (2) corresponding to the respective communication protocols.

When the LEC of the present invention joins a normal LAN emulation environment, it performs a normal joining operation and all broadcast packets are
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,
It is possible to reduce the load of concentrated broadcast packets on one BUS and prevent delays and discards of data transfer in network communication.

The reason is that, in the present invention, a plurality of BUSs are installed in the network and the BUSs are assigned for each protocol.

[Brief description of drawings]

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

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

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

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

[Explanation of symbols]

11-13 terminals 21-23 ATM switch

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-11-46206 (JP, A) JP-A-11-27320 (JP, A) JP-A-8-274802 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H04L 12/56 H04L 12/46 H04L 12/66

Claims (9)

(57) [Claims] 1. A LAN emulation client ( LA
N Emulation Regarding communication between Clients ), ATM ( As
ynchronous Transfer Mode ) Network, blow
Broadcast Unknown Server ( Broadcast and Un
known Server , called "BUS")
Used for communication of each LAN emulation client
A LAN that is transmitted from the LAN emulation client to a LAN emulation server (LAN Emulation Server) that allocates a BUS for each protocol and holds a management table that associates the ATM address of the BUS with the protocol on the network. LAN Emulation Address Resolution Protocol
l) A type indicating the acquisition of the BUS ATM address for each protocol and a value indicating the protocol are added to the request message, and the LAN emulation server receiving the LAN emulation / address resolution protocol request refers to the management table. , The ATM address of the BUS of the specified protocol is acquired, and the BU for each protocol is included in the response message transmitted from the LAN emulation server to the LAN emulation client in response to the LAN emulation address resolution protocol request.
Type indicating return of ATM address of S and AT of BUS
A network load balancing method in a LAN emulation environment, wherein an M address is added. 2. The L according to claim 1 , wherein a broadcast packet of a protocol having no dedicated BUS is transmitted using the default BUS.
A network load balancing method for an AN emulation environment. 3. The LAN emulation client determines a BUS to be transmitted by determining whether the destination of the data is a broadcast packet or a protocol each time there is a data transmission request from the upper layer protocol. , At this time, if the corresponding BUS is not found, the LAN emulation server uses the default B
The network load balancing of the LAN emulation environment according to claim 1 or 2 , wherein US is notified to the LAN emulation client, and the LAN emulation client transmits the broadcast packet using the default BUS. Method. 4. The LAN emulation client is an Internet Protocol (referred to as "IP"),
Alternatively, a LAN emulation address resolution protocol request is transmitted to the LAN emulation server in order to resolve the address of the BUS for internetwork packet exchange (referred to as "IPX"), and at this time, the LAN emulation address is transmitted. A step of adding information indicating a request for acquiring the ATM address of the BUS for IP or IPX to the resolution protocol request, and the LAN emulation server receiving the request to which the information is added, the ATM address analysis request of the BUS for each protocol It recognizes that the BUS's ATM address registered in advance in the management table is detected and the BUS's ATM address is detected as a response.
Returning 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. Opening a virtual connection (VC) on the basis of the returned ATM address, and thereafter transferring an IP or IPX broadcast packet to the BUS of the corresponding protocol, respectively. The network load balancing method for a LAN emulation environment according to claim 1 . 5. In a LAN emulation system, a LAN emulation client (LAN Emulati
ATM (Asynchronous)
Transfer Mode) A network with a broadcast unknown server (Broadcast and Unknown Ser
ver., called "BUS"), LAN emulation server
A management table in which a US ATM address and a protocol are associated with each other is provided, and the LAN emulation client acquires the BUS ATM address for each communication protocol from the LA.
The LAN emulation server includes means for requesting the N emulation server, and the LAN emulation server that receives the request from the LAN emulation client refers to the management table, and the AT of the BUS for each communication protocol
The LAN emulation environment is characterized in that it comprises means for returning the type indicating the return of the M address and the ATM address of the BUS to the LAN emulation client, and assigns the BUS individually for each communication protocol between the LAN emulation clients. Network load balancing system. 6. A LAN emulation address resolution protocol 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 the protocol are added, and the LAN emulation server receiving the LAN emulation / address resolution protocol request stores the management table By referring, the ATM address of the BUS of the specified protocol is acquired, and in the response message of the address resolution protocol request transmitted from the LAN emulation server to the LAN emulation client, the B for each protocol is added.
Type indicating return of US ATM address and BUS A
6. The network load balancing system in a LAN emulation environment according to claim 5 , wherein the TM address is added and returned. 7. The L according to claim 6 , wherein a broadcast packet of a protocol having no dedicated BUS is transmitted using the default BUS.
Network load balancing system for AN emulation environment. 8. The LAN emulation client determines a BUS to be transmitted by determining whether the destination of the data is a broadcast packet or a protocol every time there is a data transmission request from the upper layer protocol, At that time, if the corresponding BUS is not found,
Wherein from a LAN emulation server, default ATM address BUS is returned, the LAN-emulation client using default BUS transmits the broadcast packet, claimed in any one of claims 5 to 7, characterized in Network load balancing system for LAN emulation environment. 9. The LAN emulation client is an Internet Protocol (referred to as "IP"),
Alternatively, a LAN emulation address resolution protocol request is transmitted to a LAN emulation server for resolving an address of a BUS for internetwork packet exchange (referred to as "IPX"), and at that time, the LAN emulation address resolution protocol is transmitted. Request is B for IP or IPX only
The LAN emulation server, to which the information indicating the acquisition request of the ATM address of the US is added, receives the LAN emulation / address resolution protocol request to which the information is added, recognizes the ATM address analysis of the BUS for each protocol, and the server itself The IP registered in advance in the management table is referred to by referring to the management table held.
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.
When the dedicated BUS ATM address does not exist in the management table, a means for returning the default BUS ATM address to the LAN emulation client is provided, and the LAN emulation client that receives the response is based on the ATM address. , the opened virtual connection (VC), thereafter, the IP or IPX broadcast packets, respectively, and transfers to the BUS of the corresponding protocol, and wherein the claim 5
A network load balancing system in the LAN emulation environment described.