Network system and method of controlling multicast group participation of mobile host

• US 6,477,149 B1
• Filed: 01/27/1999
• Issued: 11/05/2002
• Est. Priority Date: 01/30/1998
• Status: Expired due to Term

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Okanoue, Kazuhiro
• Primary Examiner(s): Chin, Wellington
• Assistant Examiner(s): PHAN, MAN U
• Application Number:
  US09/238,781
• Time in Patent Office: 1,378 Days
• Field of Search: 370/312, 370/346, 370/347, 370/280, 370/238, 370/235, 370/408, 370/390, 370/335, 455/414, 455/426, 455/432, 455/433, 455/500, 455/518, 455/519
• US Class Current: 370/312
• CPC Class Codes: H04L 12/185 with management of multicast group membership
• CPC Class Codes: H04L 12/189 in combination with wireless systems selective distribution or broadcast in wireless communication networks H04W4/06
• CPC Class Codes: H04W 4/08 User group management
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 88/16 Gateway arrangements
• CPC Class Codes: H04W 92/02 Inter-networking arrangements

Abstract

Mobile hosts have a direct participation multicast group managing unit for managing a multicast group in which the mobile hosts participate in a form of conducting multicast communication directly from a network out of a plurality of networks in which the mobile hosts themselves currently exist, an indirect participation multicast group managing unit for managing a multicast group in which the mobile hosts participate in a form of conducting multicast communication through nodes for supporting communication with the mobile hosts themselves, and a control unit for transmitting a group report message constructed of only multicast groups managed by the direct participation multicast group managing unit when receiving the group inquiry message.

Claims

1. A network system in which a plurality of networks are connected to each other through a repeater, said plurality of networks include mobile hosts capable of moving while conducting communication between said plurality of networks, fixed hosts that do not move, and mobile host supporting nodes for supporting communication with said mobile hosts, said mobile host supporting nodes are defined in said mobile hosts, respectively, said mobile hosts, when conducting multicast communication, participate in a multicast group in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts currently exist and in a form of conducting multicast communication through said nodes for supporting communication with said mobile hosts, said repeater transmits a group inquiry message for inquiring a multicast group in which said mobile hosts, said fixed hosts and said mobile host supporting nodes in said networks connected to said repeater participate, and said mobile hosts, said fixed hosts and said mobile host supporting nodes transmit a group report message in response to said inquiry message, said mobile hosts comprising:

a) direct participation multicast group managing means for managing a multicast group in which said mobile hosts participate in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts themselves currently exist;

b) indirect participation multicast group managing means for managing a multicast group in which said mobile hosts participate in a form of conducting multicast communication through said nodes for supporting communication with said mobile hosts themselves; and

c) control means for transmitting a group report message constructed of only multicast groups managed by said direct participation multicast group managing means when receiving said group inquiry message.

2. A network system according to claim 1, wherein said control means includes:

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input.

3. A network system in which a plurality of networks are connected to each other through a repeater, said plurality of networks include mobile hosts capable of moving while conducting communication between said plurality of networks, fixed hosts that do not move, and mobile host supporting nodes for supporting communication with said mobile hosts, said mobile host supporting nodes are defined in said mobile hosts, respectively, said mobile hosts, when conducting multicast communication, participate in a multicast group in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts currently exist and in a form of conducting multicast communication through said nodes for supporting communication with said mobile hosts, said repeater transmits a group inquiry message for inquiring a multicast group in which said mobile hosts, said fixed hosts and said mobile host supporting nodes in said networks connected to said repeater participate, and said mobile hosts, said fixed hosts and said mobile host supporting nodes transmit a group report message in response to said inquiry message, said mobile host supporting nodes include:

a) mobile host participation multicast group managing means for managing a multicast group in which said mobile hosts to be supported participate in a form of conducting multicast communication through said mobile host supporting nodes themselves; and

b) control means for transmitting a group report message constructed of only multicast groups managed by said mobile host participation multicast group managing means when receiving said group inquiry message.

4. A network system according to claim 3, wherein said control means includes:

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input.

5. A method of controlling multicast group participation of mobile hosts in a network system in which a plurality of networks are connected to each other through a router, each of said networks include mobile hosts capable of moving while conducting communication between said networks, and mobile host supporting nodes for supporting communication with said mobile hosts, and each of said mobile hosts, when conducting multicast communication, can participate in a multicast group in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts themselves currently exist and in a form of conducting multicast communication through said mobile host supporting nodes for supporting communication with said mobile hosts themselves, said method comprising:

a) a step in which an originator issues a multicast announce message including multicast addresses that are used for a multicast group to a scope defined by said originator;

b) a step in which said mobile hosts that exist in said scope receive said multicast announce message, and store in first group managing means of said mobile hosts themselves a multicast address of a group out of said issued multicast addresses, in which said mobile hosts participate;

c) a step in which said mobile host supporting nodes that exist in said scope receive said multicast announce message, and send notification of said issued multicast addresses to all mobile hosts that said nodes themselves support;

d) a step in which said mobile hosts that receive said notification from said mobile host supporting nodes store in second group managing means of said mobile hosts themselves a multicast address of a group out of said issued multicast addresses, and send notification of said multicast address to said mobile host supporting nodes;

e) a step in which said mobile host supporting nodes that receive said notification from said mobile hosts store said notified multicast address in group managing means of said nodes themselves;

f) a step in which said router periodically issues a group inquiry message for inquiring a participation group to a network to be connected to said router itself, and controls transfer of multicast communication in accordance with a multicast address of said participation group obtained in response thereto;

g) a step in which said mobile hosts that exist in said scope receive said group inquiry message, and issue a response message including said multicast address stored in said first group managing means of said mobile hosts themselves on condition that said mobile hosts do not receive the same contents of a response message until time of a timer for counting random time from reception of said group inquiry message is up; and

h) a step in which said mobile host supporting nodes receive said group inquiry message, and issue a response message including said multicast address stored in said group managing means of said nodes themselves on condition that said mobile host supporting nodes do not receive the same contents of a response message until time of a timer for counting random time from reception of said group inquiry message is up.

6. A network system in which a plurality of networks are connected to each other through a repeater, said plurality of networks include mobile hosts capable of moving while conducting communication between said plurality of networks, fixed hosts that do not move, and mobile host supporting nodes for supporting communication with said mobile hosts, said host supporting nodes are defined in said mobile hosts, respectively, said mobile hosts, when conducting multicast communication, participate in a multicast group in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts currently exist and in a form of conducting multicast communication through said nodes for supporting communication with said mobile hosts, said repeater issues a group inquiry message for inquiring a multicast group in which said mobile hosts, said fixed hosts and said mobile host supporting nodes in said networks connected to said repeater participate, and said mobile hosts, said fixed hosts and said mobile host supporting nodes issue a group report message in response to said group inquiry message, said mobile hosts comprising a computer and a mechanically readable recording medium which makes said computer function as:

a) direct participation multicast group managing means for managing a multicast group in which said mobile hosts participate in a form of conducting multicast communication directly from a network out of said plurality of networks in which said mobile hosts themselves currently exist;

b) indirect participation multicast group managing means for managing a multicast group in which said mobile hosts participate in a form of conducting multicast communication through said nodes for supporting communication with said mobile hosts themselves; and

c) first control means for issuing a group report message constructed of only multicast groups managed by said direct participation multicast group managing means when receiving said group inquiry message, on condition that said first control means does not receive the same contents of a group report message until time of a timer for counting random time from reception of said group inquiry message is up,

and said mobile host supporting nodes comprising a computer and a mechanically readable recording medium which makes said computer function as;

d) mobile host participation multicast group managing means for managing a multicast group in which said mobile hosts to be supported participate in a form of conducting multicast communication through said mobile host supporting nodes themselves; and

e) second control means for issuing a group report message constructed of only multicast groups managed by said mobile host participation multicast group managing means when receiving said group inquiry message, on condition that said second control means does not receive the same contents of a group report message until time of a timer for counting random time from reception of said group inquiry message is up.

7. A network system according to claim 6, wherein said timer of said first control means includes a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto, and said first control means includes:

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input.

8. A network system according to claim 6, wherein said timer of said second control means includes a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto, and said second control means includes:

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input.

9. A network system according to claim 6, wherein said timer of said first control means includes a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto, and said first control means includes:

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input, and

said timer of said second control means includes a timer for measuring random time and outputting a time-out pulse when said inquiry message reception pulse is input thereto, and

said second control means includes;

inquiry message detecting means for detecting said group inquiry message and outputting an inquiry message reception pulse;

group report message detecting means for detecting said group report message and outputting said group report message;

multicast identifier extracting means for receiving said group report message, extracting an identifier of a multicast group included in said group report message, and outputting said identifier as a reported multicast group identifier; and

group report message forming means for receiving said reported multicast group identifier, said time-out pulse, and said inquiry message reception pulse and multicast identifier to be reported, for starting when said inquiry message reception pulse is input, and after forming said group report message as a group report message to be reported based on said multicast identifier to be reported, if said reported multicast group identifier is a multicast group identifier same as said group report message to be reported, for discarding said group report message to be reported which is formed based on said same multicast group identifier, and for outputting said group report message to be reported which is not discarded when said time-out pulse is input.