Ad hoc network of mobile hosts using link table for identifying wireless links and destination addresses

• US 6,307,843 B1
• Filed: 07/17/1998
• Issued: 10/23/2001
• Est. Priority Date: 07/18/1997
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Okanoue, Kazuhiro
• Primary Examiner(s): Hsu, Alpus H.
• Assistant Examiner(s): Qureshi, Afsar M.
• Application Number:
  US09/118,758
• Time in Patent Office: 1,194 Days
• Field of Search: 370/312, 370/329, 370/331, 370/338, 370/349, 370/351, 370/390, 370/401, 370/469, 709/222, 455/450, 455/453, 455/445
• US Class Current: 370/312
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04W 40/248 Connectivity information update
• CPC Class Codes: H04W 40/30 for proactive routing
• CPC Class Codes: H04W 8/26 Network addressing or numbering for mobility support
• CPC Class Codes: H04W 84/18 Self-organising networks, e.g. ad-hoc networks or sensor networks

Abstract

In an ad hoc network of mobile hosts interconnectable by a number of wireless links, each mobile host includes a link table having a multiple entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address. Each of the mobile hosts comprises a link table having a plurality of entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address. Each mobile host is responsive to an entered destination host name for making a search through the link table, transmitting a frame containing the network layer and data link layer addresses of an entry of the link table on one of the wireless links which is indicated by the link identifier of this entry if this entry contains the destination host name. If the link table does not contain the destination host name, the mobile host scans the wireless links, broadcasts a link table request message on one of the scanned wireless links, receives a remote link table containing the destination host name, and transmits a frame containing network layer and data link layer addresses of the received link table on the wireless link on which the remote link table was received.

Claims

1. An ad hoc network comprising:

a plurality of mobile hosts interconnectable by a plurality of wireless links, each of the mobile hosts comprising;

a link table comprising a plurality of entries each containing a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address,

each of the mobile hosts being responsive to an entered destination host name for detecting one of the entries in which the destination host name is contained, transmitting a frame containing the network layer and data link layer addresses of said one entry on one of the wireless links which is indicated by the link identifier of said one entry.

2. An ad hoc network comprising:

a plurality of mobile hosts interconnectable by a plurality of wireless links, each of the mobile hosts comprising;

a link table having a plurality of entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address; and

the mobile host being responsive to an entered destination host name for making a search through the link table, transmitting a frame containing the network layer and data link layer addresses of one of the entries on one of the wireless links which is indicated by the link identifier of said one entry if said one entry contains the destination host name, scanning the wireless links if the link table does not contain the destination host name, broadcasting a link table request message on one of the scanned wireless links, receiving a remote link table containing the destination host name, and transmitting a frame containing network layer and data link layer addresses of the received link table on one of the scanned wireless links on which the remote link table was received.

3. An ad hoc network as claimed in claim 2, wherein each of the mobile hosts is arranged to:

start measuring a time lapse,

broadcast the link table of the mobile host when the measured time lapse equals a random value, and

stop measuring the time lapse and receive a broadcast link table from another mobile host if the broadcast link table arrives before the time lapse equals the random value.

4. An ad hoc network as claimed in claim 3, wherein each of the mobile hosts is arranged to:

set a timeout value into an entry of the link table when the link table is updated, and

delete the entry from the link cable if the timeout value of the entry expires.

5. An ad hoc network as claimed in claim 2, wherein each of the mobile hosts is arranged to:

establish a wireless link to a wired network,

receive a router advertisement message from the wired network at periodic intervals,

update a routing table with data of the received router advertisement message;

make a search through the link table in response to the entered destination host name,

transmit a frame according to data of an entry of the link table if the entry contains the destination host name, and

transmit a frame according to the routing table if no frame is transmitted to other mobile hosts of the ad hoc network.

6. An ad hoc network as claimed in claim 5, wherein each of the mobile hosts is arranged to:

set a timeout value into an entry of the routing table when the routing table is updated, and

delete the entry from the routing table if the timeout value of the entry expires.

7. A method of operating an ad hoc network, wherein the network comprises a plurality of mobile hosts interconnectable by a plurality of wireless links, and each of the mobile hosts includes a link table having a plurality of entries each comprising a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address, the method comprising the steps of:

detecting one of the entries in which an entered destination host name is contained; and

transmitting a frame containing the network layer and data link layer addresses of said one entry on one of the wireless links which is indicated by the link identifier of said one entry.

8. A method of operating an ad hoc network, wherein the network comprises a plurality of mobile hosts interconnectable by a plurality of wireless links, and each of the mobile hosts includes a link table comprising a plurality of entries each containing a host name, a link identifier indicating one of the wireless links, a network layer address and a data link layer address, the method comprising the steps of:

making a search through the link table in response to a destination host name entered on a mobile host of the plurality of mobile hosts;

transmitting, from the mobile host, a frame containing network layer and data link layer addresses of one of the entries if said one entry contains the destination host name;

scanning the wireless links if the link table does not contain the destination host name; and

broadcasting a link table request message on one of the scanned wireless links, receiving a link table of the destination host name, and transmitting a frame containing network layer and data link layer addresses contained in an entry of the received link table on one of the scanned wireless links on which the link table was received.

9. The method of claim 8, further comprising the steps of:

a) starting a random-interval timer at each of the mobile hosts;

b) broadcasting entry data of the mobile host when the timer expires;

c) stopping the timer and receiving a broadcast link table from another mobile host if the broadcast link table arrives before the timer expires;

d) updating the link table of the mobile host with the received link table;

e) introducing a fixed time interval; and

f) repeating steps (a) to (d).

10. The method of claim 8, further comprising the steps of:

setting a timeout value into an entry of the link table when the link table is updated by step (d), and

deleting the entry from the link table if the timeout value of the entry expires.

11. The method of claim 8, further comprising the steps of:

establishing a wireless link to a wired network;

receiving a router advertisement message from the wired network at periodic intervals;

updating a routing table with the received router advertisement message; and

transmitting a frame according to the routing table if no frame is transmitted to other mobile hosts of the ad hoc network.

12. The method of claim 11, further comprising the steps of:

setting a timeout value into an entry of the routing table when the routing table is updated, and

deleting the entry from the routing table if the timeout value of the entry expires.

13. The method of claim 8, further comprising the steps of:

a) establishing a wireless link to at least one mobile host;

b) starting a random-interval timer;

c) broadcasting a link table request message onto the wireless link when the timer expires and receiving a link table from another mobile host;

d) updating the link table with the received link table;

e) introducing a fixed time interval;

f) stopping the random-interval timer and receiving a link table request message from another mobile host if the link table request message arrives before the timer expires;

g) starting the random-interval timer,

h) broadcasting a link table when the timer expires;

i) stopping the timer and receiving a broadcast link table from another mobile host if the broadcast link table arrives before the timer expires; and

j) repeating steps (d) to (i).