DISTRIBUTED SERVICES FOR MESH NETWORKS

• US 20070140239A1
• Filed: 12/19/2006
• Published: 06/21/2007
• Est. Priority Date: 12/21/2005
• Status: Active Grant

• Current Assignee: SRI International, Inc.
• Original Assignee: PacketHop, Inc. (SRI International, Inc.)
• Inventors: Du, Fan, Bauer, Fred
• Granted Patent: US 7,808,987 B2
• Time in Patent Office: Days
• US Class Current: 370/389
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4552 Lookup mechanisms between a plurality of directories; Synchronisation of directories, e.g. metadirectories
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 61/58 Caching of addresses or names
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04W 4/00 Services specially adapted for wireless communication networks; Facilities therefor
• CPC Class Codes: H04W 74/00 Wireless channel access
• CPC Class Codes: H04W 80/04 Network layer protocols, e.g. mobile IP [Internet Protocol]
• CPC Class Codes: H04W 84/14 WLL [Wireless Local Loop]; RLL [Radio Local Loop]

Abstract

Nodes in a mesh network are configured to access centralized Internet Protocol (IP) services whenever the Internet infrastructure is accessible and then dynamically switch to providing the IP services locally in the mesh network when the Internet infrastructure is not accessible and operate through collaborative cooperation. In one embodiment, a Reported Node Time Server (RNTS) is elected when the mesh network is disconnected. In another embodiment, a Mesh Network Name Cache (MNNC) protocol pre-provisions each mesh node with the names and addresses of all other mesh nodes. In another embodiment, a Mesh Address Allocation Protocol (MAAP) provides DHCP services for DHCP clients in the mesh network.

Claims

1. A node in a mesh network, comprising:

a processor configured to access centralized Internet Protocol (IP) operational services in an Internet infrastructure and then further configured to dynamically switch to providing similar IP operational services to other nodes in the mesh network when the mesh network is disconnected from the Internet infrastructure.

2. The node according to claim 1 wherein the IP operation services dynamically provided by the processor include any one of a Network Time Protocol (NTP) service, Domain Name System (DNS) service, or Dynamic Host Configuration Protocol (DHCP) service.

3. The node according to claim 1 wherein the processor is further configured to automatically relay time or IP address information for the IP operational services to the other nodes in the mesh network that also dynamically switch to providing the IP operational services when the mesh network is disconnected from the Internet infrastructure.

4. The node according to claim 1 wherein the processor participates in an election process for operating as a master clock server for other nodes in the mesh network when the mesh network does not have access to a Network Time Protocol (NTP) server in the Internet infrastructure.

5. The node according to claim 4 wherein the election process dynamically selects one of the nodes in the mesh network as the master clock server according to how central the nodes are to the other nodes in the mesh network.

6. The node according to claim 4 wherein the election process dynamically selects one of the nodes in the mesh network as the master clock server according to the clock times reported by the nodes or according to what alternative access the nodes have to other clock references.

7. The node according to claim 4 wherein the processor dynamically switches from using the elected master clock server in the mesh network to using the NTP server when the mesh network reconnects to the Internet infrastructure.

8. The node according to claim 1 including a cache used by the processor to dynamically start operating a Mesh Address Allocation Protocol (MAAP) or Mesh Network Name Cache (MNNC) protocol whenever the mesh network cannot communicate with an Internet DNS server or Internet DHCP sever, respectively, in the Internet infrastructure, the processor also configured to dynamically switch back to using the Internet DNS server or Internet DHCP server when the mesh network reestablishes communication with the Internet infrastructure.

9. The node according to claim 8 wherein the processor is configured to receive a DNS or DHCP request from another node in the mesh network and reply with any DNS or DHCP information in the cache associated with the DNS or DHCP request, the processor further configured to forward the DNS or DHCP request to a next node in the mesh network when the cache does not contain information responsive to the DNS or DHCP request.

10. The node according to claim 9 wherein the processor is configured to assign a new IP address to a new node entering the mesh network, update the cache with a new DNS mapping including the new IP address, and then forward the cache updates to other nodes in the mesh network.

11. The node according to claim 10 wherein the processor drops a connection with the new node when the new IP address conflicts with an existing IP address assigned to another node causing the new node to reconnect to the mesh network for assignment of another new IP address.

12. A method, comprising:

operating as a node in a mesh network;

accessing centralized Internet Protocol (IP) operational services from an Internet infrastructure that include any combination of an Internet Network Time Protocol (NTP) service, Internet Domain Name System (DNS) service, or Internet Dynamic Host Configuration Protocol (DHCP) service; and

accessing corresponding IP operational services locally in the mesh network when the IP operation services are no longer accessible from the Internet infrastructure.

13. The method according to claim 12 including using a clock from an Internet NTP server in the Internet infrastructure when accessible and using a master clock provided by one of the nodes in the mesh network when the Internet NTP server is not accessible.

14. The method according to claim 13 including participating in an election process with other nodes in the mesh network for providing the master clock for the mesh network.

15. The method according to claim 12 including using domain name mappings and IP addresses provided by an Internet DNS server or Internet DHCP server when the Intent infrastructure is accessible and using domain name mappings or IP addresses provided by nodes in the mesh network when the Internet infrastructure is not accessible.

16. The method according to claim 15 including:

operating a cache that contains the domain name mappings;

receiving a DNS request from another node in the mesh network;

returning DNS mappings from the cache corresponding to the DNS request;

forwarding the DNS request to another node in the mesh network when the cache does not contain a domain name mapping corresponding with the DNS request; and

updating the cache with any new domain name mappings received from other nodes in the mesh network.

17. The method according to claim 15 including:

receiving a DHCP request from a new node connecting to the mesh network;

forwarding the DHCP request to an Internet DHCP server when the mesh network is connected to the Internet infrastructure; and

responding to the DHCP request by assigning an IP address to the new node when the mesh network is not connected to the Internet infrastructure.

18. The method according to claim 17 including:

forwarding the new assigned IP address to other nodes in the mesh network;

determining if the new IP address conflicts with any other IP addresses in the mesh network;

forcing one of the nodes having conflicting IP addresses to disconnect from the mesh network; and

assigning a different new IP address to the node forced to disconnect from the mesh network when the node reconnects to the mesh network.

19. A mesh network, comprising:

multiple different nodes configured to communicate directly with each other and also configured to forward certain communications to other nodes in the mesh network and to devices in an Internet infrastructure, the nodes further configured to access centralized Internet Protocol (IP) services when the mesh network has access to the Internet infrastructure and then dynamically convert to providing local IP services when the mesh network does not have access to the Internet infrastructure.

20. The mesh network according to claim 19 wherein the nodes are further configured to provide a reference clock, domain name mappings, and IP addresses to other nodes in the mesh network.

21. The mesh network according to claim 20 wherein the IP services include an Internet Network Time Protocol (NTP) service, Internet Domain Name System (DNS) service, and an Internet Dynamic Host Configuration Protocol (DHCP) service.