JP2000183891A - Method and system for automatically participating in multicast group - Google Patents

Abstract

PROBLEM TO BE SOLVED: To actualize a method for automatically participating in a desired multicast group without changing the setting of configuration information, etc., on a host side. SOLUTION: For ATM-LAN, an MARS(multicast address resolution server) is mounted on a router node in network environment composed of subnets and when the MARS receives a multicast registration request message that an MARS client sends to an AnyCast address of the MARS, the message is transferred to another MARS managing the pertinent network according to a transmission source IP address and routing information if the multicast registration request message is not of a network managed by the MARS. Then the MARS sends an answer message to the registration request message back to the MARS client, which once receiving the answer message, sends a request for participation in the multicast group to the other MARS.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and system for multicast communication, and more particularly to a method and system for joining a host to a multicast group in ATM-LAN multicast communication.

[0002]

2. Description of the Related Art In a multicast, one packet is simultaneously transmitted from a transmission source to a plurality of destinations.
In (Internet Protocol) multicasting, a host, for example, uses IGMP (Internet Group Management).
Protocol) to join a multicast group in the subnet to which it belongs.

[0003] Regarding IP multicast on ATM (Asynchronous Transfer Mode), for example, RFC2022 [Support for I
P Multicast Over UNI 3.0 / 3.1 Based ATM Netw
roks], the multicast address resolution server (Mult
It describes the use of ATM Multicast Server (MCS) support and ATM point-to-multipoint VC support by icast Address Resolution Server (referred to as "MARS"). MARS is ATM A
It is an extension of the RP (Address Resolution Protocol) server that manages point-to-multipoint VCs for all endpoints that need masticcast support.

A server performing an Anycast service directly registers its own AnyCast address (also referred to as a "functional address") in a switch to be connected, and the switch registers a server to be accommodated in a routing table. To access the server, the function address of the server is specified in the Anycast address format. When the switch detects the Anycast address, the switch searches its routing table and routes to the server.

[0005]

SUMMARY OF THE INVENTION MARS AnyCa
The use of the st address eliminates the need to set the MARS ATM address.
To connect to the st address, you can only participate in the nearest, that is, MARS on the same subnet as your own node,
I could not join another MARS beyond the subnet.

Accordingly, the present invention has been made in view of the above problems, and has as its object the purpose of
It is an object of the present invention to provide a method and a system capable of automatically joining a multicast group to be joined without changing the settings such as configuration information of an RS client.

[0007]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a method of transmitting a MARS protocol message between MARSs so that an MARS address can be used as a MARS address.
When the yCast address is set, the MARS client is automatically registered in the optimum MARS and can join the multicast group.

[0008]

Embodiments of the present invention will be described. The present invention provides a LAN (local area network) (ATM-LAN) using an ATM by implementing MARS on a router node under a network environment composed of a plurality of subnets.
MARS Client (MARS Client)
When the MARS receives the multicast registration request message transmitted to the Anycast address of MARS, the multicast registration request message is
If the network is not managed by the RS, it is transferred to another MARS managing the network in accordance with the source IP address and the routing information,
The other MARS returns a response message to the registration request message to this MARS client,
Upon receiving the response message, the ARS client transmits a join request message for joining the multicast group to the other MARS.

In another MARS, upon receiving a request message to join a multicast group from a MARS client, the response message is notified to all MARS clients through the cluster control VC.

[0010]

An embodiment of the present invention will be described. FIG.
FIG. 2 is a diagram showing a configuration of one embodiment of the present invention. Referring to FIG. 1, in the present embodiment, three subnets A, B,
C (101, 102, 103), a first router 13 interconnecting subnets A and B, and a first router 13
Switch 11 connected to the first switch 11 and the first switch 11
Hosts 1, 2, and 3 connected to
C, a second router 14 interconnecting the C, a second switch 12 connected to the second router 14, a host 4 connected to the second switch 12, and first and second routers 13. , 14 mounted on the first MARS 15,
And a second MARS 16.

At this time, the first MARS 15 manages the subnet A, the second MARS 16 manages the subnet C, and the hosts 1, 2, and 3 belong to the subnet A. As the MARS client, the first router 13 It is registered with the above first MARS 15 and forms a multicast group A (20).

Also, the first router 13 has a second MAR
The ATM address of S16 and the ATM address of the first MARS 15 are preset in the second router 14, respectively, and the AnyCast address to the MARS 15 and 16 is set in the first and second switches 11 and 12, respectively. Have been.

FIG. 2 is a flowchart for explaining the operation of one embodiment of the present invention. The operation of the embodiment of the present invention will be described in detail with reference to FIGS.

A description will be given of the operation in the case where the host 4 which originally belongs to the subnet A and has joined the multicast group A is connected to another subnet C, and in this state, rejoins the original multicast group A.

First, when the host 4 joins the multicast group A, the Any4 of the second MARS 16
A SETUP (setup) message is transmitted to the st address, a VC (virtual channel) is opened with the second router 14, and a registration request message is transmitted using this VC (step S1).

The second MARS 16, which has received the registration request message from the host 4, checks the source protocol address of the message (in this case, the IP address of the host 4) to determine which subnet of the multicast group Determine if you are participating in
(Step S2).

In the second MARS 16, if this IP address does not belong to the subnet managed by itself,
By looking at the routing table of P, it forwards to MARS on the adjacent router (step S3).

By repeating the processing of steps S2 and S3, the first MARS 15 supporting the IP address of the transmission source of the registration request message
Will receive a registration request message.

The first MARS 15 sends a ClusterControl VC (cluster control VC,
“CCVC”), and returns a response message to the registration request message to the host 4 (step S4).

When the host 4 receives the response message from the first MARS 15, the host 4 next sends a MARS request message for joining the multicast group A.
Send to

Here, MARS is the first MARS1.
5, if a REDIRECT_MAP (redirect map) message is received and the ATM address of the first MARS 15 is known, it is the first MARS 15.

Otherwise, it is the second MARS 16 and the participation request message is delivered to the first MARS 15 by repeating the processing from step S1 to step S3 (step S5).

When the first MARS 15 receives the request message to join the multicast group A from the host 4, it sends a response message to all MARS clients via CCVC (step S6).

The response message from the second MARS 16 is received by all MARS clients.

Each MARS client checks whether it is related to the multicast group in which it is participating (step S7).

The host 4 uses the member list included in the response message to point-to-multipoint (Point-to-MultiPoint, referred to as "P2MP") to the hosts 1, 2, and 3 belonging to the same multicast group A.
Open a VC.

Similarly, the hosts 1, 2, and 3 establish a P2MP VC with respect to the host 4 (step [S8]).

By the above procedure, the host 4 can join the multicast group A of the original subnet A and transmit the multicast data to the members of the multicast group.

[0029]

As described above, according to the present invention,
By setting the AnyCast address of MARS in the switch, it is possible to automatically join the multicast group that the user wants to join without changing the settings such as the configuration information of the MARS client.

The reason is that the MARS client
A VC is attached to the AnyCast address of the RS, a join request message is transmitted using this VC, and the MARS receiving this message is forwarded to the MARS managing the corresponding network according to the source IP address and the routing information. This is because it was configured to perform

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a network configuration according to an embodiment of the present invention.

FIG. 2 is a flowchart for explaining the operation of one embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 1st switch 12 2nd switch 13 1st router 14 2nd router 15 1st MARS 16 2nd MARS 20 Multicast group 101-103 Subnet

Claims (5)

[Claims] 1. By transmitting a MARS protocol message between MARS (multicast address resolution servers), Anycast is transmitted as a MARS address.
If (anycast) address is set, M
A method for joining a multicast group, wherein an ARS client is automatically registered in an optimal MARS and can join a multicast group. 2. A network system comprising a router interconnecting subnets and one or more hosts having the subnets and switches connected to the hosts and the routers, wherein MARS (multicast) is provided on a router node connected to the switches. Address switch), the switch sets the MARS AnyCast address, the host opens a VC (virtual channel) to the MARS AnyCast address, and joins the multicast group using the VC. In the MARS that transmitted the request message and received the join request message, from the source IP (Internet Protocol) address,
The multicast registration request message is the MARS
And transmitting the participation request message to a neighboring MARS managing the corresponding network according to the routing information if the network does not belong to the subnet managed by the multicast communication system. 3. The MARS managing the network.
Returns a response message to the registration request message to the MARS client. When the MARS client receives the response message, the MARS client sends a join request message for joining the multicast group to MARS managing the network. In the MARS that transmits and manages the network,
3. The multicast communication system according to claim 2, wherein upon receiving a request message to join the multicast group from the ARS client, the response message is notified to a subordinate MARS client through the cluster control VC. 4. The multicast communication system according to claim 2, wherein said router holds an address of MARS on another router node in a subnet interconnected via said router. 5. A MARS (multicast address resolution server) provided on a router node of a network system comprising a router interconnecting subnets, and one or more hosts having subnets and a switch connected to the host and the router. ), When the host opens a VC (virtual channel) to the Anycast address of the MARS and sends a request message to join a multicast group using the VC, the MARS sends the join request message Receive,
When it is determined from the source IP address that the multicast registration request message does not belong to the subnet managed by the MARS, according to the routing information, the neighboring MARS managing the corresponding network is A MARS device for forwarding a participation request message.