Digital network modem with an integrated DHCP server

• US 20060206625A1
• Filed: 02/24/2006
• Published: 09/14/2006
• Est. Priority Date: 10/30/1998
• Status: Active Grant

• Current Assignee: Sangoma US, Inc. (Sangoma Technologies Corporation)
• Original Assignee: Dialogic, Inc. (Enghouse Systems Limited)
• Inventors: Moineau, Gilbert
• Granted Patent: US 7,636,775 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: H04L 12/4612 LAN interconnection over narrowband networks, e.g. N-ISDN, PSTN, X.25
• CPC Class Codes: H04L 45/02 Topology update or discovery
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5076 Update or notification mechanisms, e.g. DynDNS
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

The digital network modem has a built-in Dynamic Host Configuration Protocol (DHCP) mechanism for dynamically assigning network addresses to clients on the local network. To prevent confusion with a potentially existing DHCP server on the local network, an autosense mechanism is provided to detect the existence of a DHCP server and disable the internal, built-in DHCP mechanism. At power-on, the modem has no knowledge of clients on the local network, and the addresses in use are checked prior to operation. Addresses in use are placed in a list in a store of unknown addresses, and are not assigned to clients requesting DHCP addresses. When a DHCP client requests an address and has as its current address one of the addresses on the list, the current address is removed from the list. The list of unusable addresses is thus minimized and the same address will not be used for two clients.

Claims

1. A network modem device comprising an integrated mechanism for dynamically assigning network addresses on a network. The network modem device comprises a controller circuit detecting a presence of a dynamic address assignment server on the network;

an interrupter disabling the integrated mechanism when the controller circuit detects the server; and

a memory store of unknown used addresses. The integrated mechanism comprises a start-up mechanism checking the availability of addresses on the network and placing used addresses in the memory store of unknown used addresses and an address manager selecting new addresses not included in the store of unknown used addresses, and removing addresses from the store of unknown used addresses when a client having one of the addresses in the store of unknown used addresses requests a dynamically assigned address.

2. The device according to claim 1, wherein said device is a digital network modem.

3. The device according to claim 2, wherein said device is an ISDN modem.

4. The device according to one of claims 1 to 3, wherein said integrated mechanism provides a DHCP server function.

5. The device according to claim 4, wherein said controller circuit broadcasts a DHCP discover message on the network and listens to a response to detect said presence of said server.

6. A method of enabling/disabling a mechanism for dynamically assigning network addresses on a network, the mechanism being integrated into a network modem device. The method comprises detecting a presence of a dynamic address assignment server on the network;

and disabling the integrated mechanism when the server is detected;

checking the availability of addresses on the network after power on and loss of memory of previously dynamically assigned addresses;

storing the used addresses in a store of unknown used addresses;

selecting new addresses not stored in response to a request for a dynamically assigned address; and

removing an address from the store of unknown used addresses when a client having one of the addresses in the store of unknown used addresses requests a dynamically assigned address.

7. The method according to claim 6, wherein said device is a digital network modem.

8. The method according to claim 7, wherein said device is an ISDN modem.

9. The method according to one of claims 6 to 8, wherein said integrated mechanism provides a DHCP server function.

10. The method according to claim 9, wherein said detecting comprises broadcasting from said device onto said network a DHCP discover message and listening to a response to detect said presence of said server.