Automatic reconfiguration of layer 3 device to layer 2 device upon detection of upstream NAT/NAPT device

• US 20060291443A1
• Filed: 06/13/2005
• Published: 12/28/2006
• Est. Priority Date: 06/13/2005
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Harrington, Kendra S., Huotari, Allen J., Brenes, Manrique
• Granted Patent: US 8,619,765 B2
• Time in Patent Office: Days
• US Class Current: 370/351
• CPC Class Codes: H04L 45/60 Router architectures
• CPC Class Codes: H04L 49/602 Multilayer or multiprotocol switching, e.g. IP switching
• CPC Class Codes: H04L 61/2514 between local and global IP addresses
• CPC Class Codes: H04L 61/2546 Arrangements for avoiding unnecessary translation
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Abstract

In one embodiment, a network device is provided that includes a DHCP server; a NAT/NAPT facility; and a logic engine configured to detect a presence of an upstream NAT/NAPT service, the logic engine being further configured to disable the DHCP server and the NAT/NAPT facility in response to detecting the presence of the upstream NAT/NAPT service.

Claims

1. A network device, comprising:

a DHCP server;

a NAT/NAPT facility; and

a logic engine configured to detect a presence of an upstream NAT/NAPT service, the logic engine being further configured to disable the DHCP server and the NAT/NAPT facility in response to detecting the presence of the upstream NAT/NAPT service.

2. The network device of claim 1, wherein the logic engine comprises a STUN client.

3. The network device of claim 2, wherein the logic engine is configured to detect the presence of the upstream NAT/NAPT service by comparing an IP address and port number for a binding request and a corresponding binding response.

4. The network device of claim 1, wherein the network device comprises a router having a plurality of LAN ports, and wherein the DHCP server is configured to assign temporary IP addresses to client devices coupled through the plurality of LAN ports if the logic engine does not detect the presence of the upstream NAT/NAPT service.

5. The router of claim 4, wherein the logic engine comprises a microprocessor.

6. The network device of claim 1, wherein the logic engine comprises a UPnP client, the logic engine being configured to detect the presence of the upstream NAT/NAPT service by detecting the presence of an upstream UPnP Internet Gateway Device (IGD).

7. The network device of claim 6, wherein the network device comprise a router having a plurality of LAN ports, and wherein the DHCP server is configured to assign temporary IP addresses to client devices coupled through the plurality of LAN ports if the logic engine does not detect the presence of an upstream UPnP IGD.

8. The router of claim 7, wherein the router is configured to function as an IEEE 802.11 access point (AP) if the logic engine does not detect the presence of an upstream UPnP IGD.

9. A method of configuring a router, comprising:

powering up the router;

in response to powering up the router, detecting whether there is NAT/NAPT service upstream to the router;

if upstream NAT/NAPT service is detected, disabling a DHCP server and a NAT/NAPT facility within the router.

10. The method of claim 9, wherein the router includes a STUN client, and wherein the detection of whether there is an upstream NAT/NAPT service comprises comparing STUN messages from the STUN client and from a STUN server.

11. The method of claim 10, wherein the comparison of the STUN messages comprises:

issuing a binding request from the STUN client to the STUN server;

in response to receiving the binding request at the STUN server, receiving a binding response at the STUN client;

comparing an IP address and port for the binding request and the binding response; and

if the comparison determines that the IP address and port for the binding request and binding response differ, indicating the presence of the upstream NAT/NAPT service.

12. The method of claim 9, wherein the router includes a UPnP client, and wherein the detection of whether there is an upstream NAT/NAPT service comprises determining if there is an upstream UPnP Internet Gateway Device (IGD).

13. The method of claim 12, further comprising:

in response to not detecting the presence of an upstream UPnP IGD, configuring the router to be a UPnP IGD.

14. The method of claim 9, further comprising:

if the upstream NAT/NAPT service is not detected, enabling the DHCP server to issue a plurality of temporary IP addresses to a corresponding plurality of LAN clients and enabling the NAT/NAPT facility to perform IP address translations for the plurality of LAN clients.

15. A network device, comprising:

a DHCP server;

a NAT/NAPT facility;

detecting means for detecting a presence of an upstream NAT/NAPT service, and

means for disabling the DHCP server and the NAT/NAPT facility in response to the detecting means detecting the presence of the upstream NAT/NAPT service.

16. The network device of claim 15, wherein the means for detecting the presence of upstream NAT/NAPT service comprises a STUN client.

17. The network device of claim 16, wherein the STUN client is configured to detect the presence of the upstream NAT/NAPT service by comparing an IP address and port number for a binding request and a corresponding binding response.

18. The network device of claim 15, wherein the network device comprise a router having a plurality of LAN ports, wherein the DHCP server is configured to assign temporary IP addresses to client devices coupled through the plurality of LAN ports if the detecting means does not detect the presence of the upstream NAT/NAPT service.

19. A network device, comprising:

a DHCP server;

a NAT/NAPT facility, wherein the router is configured such that the DHCP server and the NAT/NAPT facility are disabled after power-up of the router; and

a logic engine configured to detect whether upstream NAT/NAPT service exists, the logic engine being further configured to enable operation of the DHCP server and the NAT/NAPT facility in response to detecting the absence of upstream NAT/NAPT service.

20. The network device of claim 19, wherein the logic engine comprises a STUN client.