Method for domain name service (DNS) in a wireless ad hoc network

• US 20060013158A1
• Filed: 07/19/2004
• Published: 01/19/2006
• Est. Priority Date: 07/19/2004
• Status: Active Grant

• Current Assignee: Motorola Solutions, Inc.
• Original Assignee: Motorola, Inc. (Motorola Solutions, Inc.)
• Inventors: Narayanan, Vidya, Kumar, Surender, Ahuja, Ramandeep
• Granted Patent: US 7,317,918 B2
• Time in Patent Office: Days
• US Class Current: 370/328
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• 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 a wireless ad hoc network comprising a plurality of nodes, a primary node receives a domain name service (DNS) query from a node. The primary node determines whether the query can be resolved based on cached information. If the DNS query can be resolved based on cached information, the primary node sends a response to the node. If the DNS query cannot be resolved based on cached information, the primary node sends the DNS query outside the ad hoc network for resolution.

Claims

1. In a wireless ad hoc network comprising a plurality of nodes, a method comprising the steps of:

at a first primary node;

receiving a domain name service (DNS) query from a node;

determining whether the query can be resolved based on cached information; and

if the DNS query can be resolved based on cached information, sending a response to the node;

otherwise, sending the DNS query outside the ad hoc network for resolution.

2. The method of claim 1 further comprising the steps of, if the DNS query cannot be resolved based on cached information:

receiving a response to the DNS query from outside the ad hoc network;

caching the response at the first primary node; and

sending the response to the DNS query to the node.

3. In a wireless ad hoc network comprising a plurality of nodes, a method comprising the steps of:

receiving a broadcast of a DNS database from a primary node;

periodically receiving a broadcast of a delta change to the DNS database from the primary node; and

if unable to resolve a DNS query, sending the DNS query to the primary node for resolution.

4. The method of claim 3 further comprising the step of, if the primary node becomes unavailable, participating in a process to elect a new primary node.

5. The method of claim 3 wherein the primary node becomes unavailable if the primary node leaves the ad hoc network or if the primary node becomes non-responsive for a predetermined amount of time.

6. In a wireless ad hoc network comprising a plurality of nodes and a plurality of virtual local area networks (VLANs), wherein each VLAN has a primary node, a method comprising the steps of:

at a first primary node within a first VLAN;

receiving a domain name service (DNS) query from a node;

determining whether the DNS query can be resolved at the first primary node; and

if the DNS query can be resolved at the first primary node, sending a response to the DNS query to the node;

otherwise, sending the DNS query to a second primary node within a second VLAN for resolution.

7. The method of claim 6 further comprising the steps of:

receiving a response to the DNS query from the second primary node;

caching the response at the first primary node; and

sending the response to the DNS query to the node.

8. The method of claim 7 wherein the second primary node sent the DNS query outside the ad hoc network to obtain the response to the DNS query.

9. The method of claim 7 wherein the second primary node resolved the DNS query at the second primary node based on cached information.

10. The method of claim 6 further comprising the step of, if a response to the DNS query is not received from the second primary node after a predetermined amount of time has lapsed, sending the DNS query outside the ad hoc network for resolution.

11. The method of claim 10 wherein the step of sending the DNS query outside the ad hoc network for resolution comprises one of the following steps:

sending the DNS query outside the ad hoc network directly;

sending the DNS query outside the ad hoc network indirectly via at least one node belonging to the first VLAN; and

instructing the second primary node to send the DNS query outside the ad hoc network.

12. The method of claim 6 further comprising the steps of:

periodically sending a first message to at least a portion of the primary nodes in the ad hoc network if a node in a first VLAN has connectivity outside the ad hoc network; and

periodically receiving a second message from at least a portion of the primary nodes in the ad hoc network if a node in another VLAN has connectivity outside the ad hoc network.

13. The method of claim 6 further comprising the steps of:

sending a first broadcast of a DNS database to a plurality of nodes within the first VLAN;

periodically sending a second broadcast of a delta change of the DNS database to the plurality of nodes in the first VLAN; and

if a node belonging to the first VLAN is unable to resolve a DNS query, sending the DNS query to the first primary node for resolution.

14. In a wireless ad hoc network comprising a plurality of nodes, a method comprising the steps of:

electing a first primary node and a first secondary node from the plurality of nodes, wherein the first primary node comprises a domain name service (DNS) database, and the first secondary node mirrors the DNS database at the first primary node;

routing domain name service queries from the plurality of nodes to the first primary node for resolution; and

if the first primary node becomes unavailable, appointing the first secondary node as a second primary node, electing a second secondary node, and routing subsequent domain name service queries from the plurality of nodes to the second primary node for resolution, wherein the second secondary node mirrors the DNS database at the second primary node.

15. The method of claim 14 wherein the first primary node becomes unavailable if the first primary node leaves the ad hoc network or if the first primary node becomes non-responsive for a predetermined amount of time.

16. The method of claim 14 wherein the steps of electing is performed by the plurality of nodes implementing an election algorithm.