Network system comprising a plurality of lans connected to an ISDN via a plurality of routers, each capable of automatically creating a table for storing router information

• US 5,351,237 A
• Filed: 06/04/1993
• Issued: 09/27/1994
• Est. Priority Date: 06/05/1992
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ito, Yuji, Shinohara, Takahiro
• Primary Examiner(s): Safourek, Benedict V.
• Application Number:
  US08/071,776
• Time in Patent Office: 480 Days
• Field of Search: 370/16, 370/58.2, 370/60, 370/94.1, 370/94.3, 370/110.1, 370/85.13, 370/58.3, 379/220, 379/221
• US Class Current: 370/392
• CPC Class Codes: H04L 12/4612 LAN interconnection over narrowband networks, e.g. N-ISDN, PSTN, X.25
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/42 Centralised routing
• CPC Class Codes: H04Q 11/0428 Integrated services digital network, i.e. systems for transmission of different types of digitised signals, e.g. speech, data, telecentral, television signals

Abstract

In a network system including a plurality of LANs connected to an ISDN via a plurality of routers each of which includes a table for router information, each router sets local router information and main/sub setting information. Each sub-router sets main router information which is written in said table. Each sub-router sends an enquiry packet including the local router information to the main router. The main router receives the enquiry packet, enters the local router information in the table, and sends, to each sub-router, a reply packet including the local router information stored in the table. Each sub-router receives the reply packet and enters the local router information in the table. On the basis of the router information stored in the table, each router renews routing information.

Claims

1. In a network system comprising a plurality of LANs (Local Area Networks) connected to an ISDN (Integrated Services Digital Network) via first through N-th routers where N represents a predetermined natural number which is not less than three, said LANs being divided into first through N-th LAN groups which are connected to said first through said N-th routers, respectively, each of said first through said N-th LAN groups comprising at least one of said LANs, an n-th router being for connecting an n-th LAN group through said ISDN with at least one of said first through said N-th LAN groups except for said n-th LAN group, where n represents each of 1 through N, said n-th router including a table for storing router information, in connection with all of said first through said N-th routers except for said n-th router, the improvement wherein said n-th router comprises:

local router information setting means for receiving local router setting, information indicative of an n-th router IP (Internet Protocol) address and an n-th router telephone number both of which are assigned to said n-th router; and

main/sub setting means for receiving n-th main/sub setting information indicating whether said n-th router should be operable as either a main router or one of sub-routers, whereby a particular one of said first through said N-th routers is operable as said main router while remaining routers except for said main router are operable as said sub-routers.

2. A network system as claimed in claim 1, wherein each of said sub-routers comprises:

main router information setting means for setting main router information indicative of a main router IP address and a main router telephone number both of which are assigned to said main router; and

main router information writing means, connected to said main router information setting means and said table, for writing said main router information in said table.

3. A network system as claimed in claim 2, wherein each of said sub-routers comprises enquiry packet sending means, connected to said local router information setting means and said table, for sending an enquiry packet including said local router information to said main router on the basis of said main router information stored in said table,

said main router comprising:

enquiry packet receiving means for receiving said enquiry packet from each of said sub-routers;

main entering means, connected to said enquiry packet receiving means and said table, for entering the local router information included in said enquiry packet in said table; and

reply packet sending means, connected to said table, for sending, to each of said sub-routers, a reply packet including the local router information stored in said table;

each of said sub-routers further comprising;

reply packet receiving means for receiving said reply packet from said main router; and

local entering means, connected to said reply packet receiving means and said table, for entering the local router information included in said reply packet in said table.

4. A method of creating a table included in each of first through N-th routers for connecting a plurality of LANs (Local Area Networks ) via an ISDN ( Integrated Services Digital Network) in a network system where N represents a predetermined natural number which is not less than three, said LANs being divided into first through N-th LAN groups which are connected to said first through said N-th routers, respectively, each of said first through said N-th LAN groups comprising at least one of said LANs, an n-th router being for connecting an n-th LAN group through said ISDN with at least one of said first through said N-th LAN groups except for said n-th LAN group, where n represents each of 1 through N, the table of said n-th router being for storing router information in connection with all of said first through said N-th routers except for said n-th router, said method comprising the steps of:

setting, in said n-th router, local router information indicative of an n-th router IP (Internet Protocol) address and an n-th router telephone number both of which are assigned to said n-th router;

setting, in said n-th router, n-th main/sub setting information indicating that said n-th router should be operable as either a main router or one of sub-routers, whereby a particular one of said first through said N-th routers is operable as said main router while remaining routers except for said main router are operable as said sub-routers;

setting, in each of said sub-routers, main router information indicative of a main router IP address and a main router telephone number both of which are assigned to said main router;

writing, each of said sub-routers, said main router information in said table;

sending, from each of said sub-routers to said main router, an enquiry packet including said local router information on the basis of said main router information stored in said table;

receiving, in said main router, said enquiry packet from each of said sub-routers;

entering, in said main router, the local router information included in said enquiry packet in said table;

sending, from said main router to each of said sub-routers, a reply packet including the local router information stored in said table;

receiving, in each of said sub-routers, said reply packet from said main router; and

entering, in each of said sub-routers, the local router information included in said reply packet in said table.