Method and system for addressing network host interfaces from a cable modem using DHCP

• US 6,058,421 A
• Filed: 02/04/1998
• Issued: 05/02/2000
• Est. Priority Date: 02/04/1998
• Status: Expired due to Term

• Current Assignee: Hewlett Packard Enterprise Development LP (Hewlett-Packard Enterprise Company)
• Original Assignee: 3Com Corporation (HP Inc.)
• Inventors: Robinson, Philip T., Beser, Nurettin B., Fijolek, John G.
• Primary Examiner(s): Asta, Frank J.
• Assistant Examiner(s): Prieto, Beatriz
• Application Number:
  US09/018,784
• Time in Patent Office: 818 Days
• Field of Search: 709/224, 709/203, 709/202, 709/217, 709/218, 709/219, 709/226, 709/227, 709/231, 709/238, 709/245, 711/200, 370/312, 370/352, 370/389, 370/432, 370/475, 364/705.05, 348/6, 348/734, 359/164, 359/165
• US Class Current: 709/225
• CPC Class Codes: H04L 12/2801 Broadband local area networks
• CPC Class Codes: H04L 61/103 across network layers, e.g. resolution of network layer into physical layer addresses or address resolution protocol [ARP]
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Abstract

A method and system are provided to allow a cable modem to discover an address of a network host interface on a cable television network to connect the cable modem to a data network (e.g., the Internet). The cable modem is used in a data-over-cable system with telephony return. The cable modem is connected to a cable television network over a downstream cable data channel and connected to a public switched telephone network over a serial telephone line. The method provides a way for the cable modem to determine the address of network host interfaces (e.g., Internet Protocol hosts) available on the cable television system via the upstream channel connected to public switched telephone network. The method includes using existing Dynamic Host Configuration Protocol ("DHCP") messages and message fields to discover network host interfaces available on the cable television system even though the cable modem only has downstream connection from the cable television network. The method and are used without changes to DHCP and can also be used in a data-over-cable system without telephony return.

Claims

1. In a data-over-cable system with telephony return including a plurality of network devices, a method of addressing network host interfaces, the method comprising the following steps:

receiving upon initialization on a first network device on a downstream cable connection from a second network device on a first network, an information message including a first network address used to identify a downstream cable connection from the second network device, wherein the first network device receives data on the downstream cable connection from the second network device and sends data on an upstream telephony connection to a third network device on a second network;

creating a first message with a first message type with a network address allocation protocol on the first network device, the first message having the first network address from the information message in a first message field, wherein the first message is used to request a second network address for communicating with a third network;

sending the first message from the first network device on the upstream telephony connection to the third network device on the second network;

forwarding the first message from the third network device on the second network to a plurality of network host interfaces available on the first network using the first network address from the first field in the first message;

creating a plurality of second messages with a second message type using the network address protocol with the first network address from the first message in a first message field and a second network address in a second message field, on the plurality of network host interfaces available on the first network in response to the first message forwarded from the first network by the second network;

forwarding the plurality of second messages from the first network via the second network device over the downstream connection to the first network device using the first network address from the first message field to identify the downstream connection to the first network device from the second network device;

selecting on the first network device, a second network address from one of the plurality of second messages from one of the network host interfaces available on the first network and thereby establishing a virtual connection between the third network and the first network device,

wherein the virtual connection includes receiving data from the third network on the second network address on the second network device on the first network, and forwarding the data from the second network device over the downstream cable connection to the first network device, and sending data including the second connection address from the first network device to the third network over the upstream telephony connection via the third network device on the second network.

2. A computer readable medium having stored therein instructions for causing a central processing unit to execute the method of claim 1.

3. The method of claim 1 wherein the first network device is a cable modem, the first network is a cable television network, the second network is a public-switched telephone network and the third network is a data network.

4. The method of claim 3 wherein the data network is any of Internet or an intranet.

5. The method of claim 1 wherein the downstream cable connection is a cable television connection, and the upstream telephony connection is a serial line connection.

6. The method of claim 1 wherein the first message is a Dynamic Host Configuration Protocol discover message and the first message field is a Dynamic Host Configuration Protocol message giaddr-field including an Internet protocol address for a downstream cable channel on a downstream cable connection from a cable modem termination system on the first network.

7. The method of claim 1 wherein the information message is a cable modem termination system information message sent by the first network to report first network information to the first network device.

8. The method of claim 1 wherein the first network includes a telephony remote access concentrator and the second network includes a cable modem termination system.

9. The method of claim 1 wherein the plurality of network host interfaces include a plurality of Internet Protocol addresses.

10. The method of claim 1 wherein the Internet Protocol address used to identify a downstream cable connection from the second network device includes an Internet Protocol address used to identify an individual downstream cable channel on the downstream cable connection.

11. In a data-over-cable system with a plurality of network devices, a method of discovering network interfaces, the method comprising the following steps:

receiving on an upstream telephony connection on a third network device on a second network a first message from a first network device on a first network to discover network host interfaces available on the second network device on the first network, wherein the first message includes a first message field with a first network address for a downstream cable connection from the second network device to the first network device;

broadcasting the first message from the third network device to a plurality of protocol proxies on the second network;

forwarding the first message from the plurality of protocol proxies on the second network to a plurality of protocol servers on the first network using the first network address for the downstream cable connection from the second network device, the plurality of protocol servers providing services for the second network device to a plurality of network host interfaces associated with the second network device;

creating a plurality of second messages with a second network address on the plurality of network host interfaces associated with the second network device, wherein the plurality of second network addresses are available network addresses on the second network device for communicating with a third network;

receiving the plurality of second messages on the second network device from the plurality of protocol servers using the first network address in the first message field from the first message, wherein the plurality of second messages include a second connection address field for a plurality of available network addresses; and

forwarding the plurality of second messages from the second network device over the downstream cable connection to the first network device,

wherein the first network device selects a second network address from one of the plurality of second messages to establish a virtual connection with the third network.

12. A computer readable medium having stored therein instructions for causing a central processing unit to execute the method of claim 11.

13. The method of claim 11 wherein the first network is a cable television network, the second network is a public-switched telephone network and the third network is a data network.

14. The method of claim 11 wherein the plurality of first protocol proxies are Dynamic Host Configuration Protocol proxies, the plurality of first protocol servers are Dynamic Host Configuration Protocol servers and the first message field is a Dynamic Host Configuration Protocol message giaddr-field.

15. The method of claim 11 wherein the the third network is a data network.

16. The method of claim 15 wherein the data network is any of the Internet or an intranet.

17. The method of claim 11 wherein the second network device is a cable modem termination system, the third network device is a telephony return access concentrator and the first network device is a cable modem.

18. A data-over-cable system with telephony return, the system comprising in combination:

a plurality of Dynamic Host Configuration Protocol proxies associated with a telephony remote access concentrator, for forwarding requests for a network address for a data network to a plurality of Dynamic Host Configuration Protocol servers associated with a cable modem termination system using a network address for a downstream cable connection from the cable modem termination system to a cable modem;

a plurality of Dynamic Host Configuration Protocol servers associated with a cable modem termination system, for accepting network address requests from Dynamic Host Configuration Protocol proxies for network host interfaces using a network address for a downstream cable connection from the cable modem termination system to a cable modem;

a plurality of network host interfaces available on the cable modem termination system, for providing network addresses to a data network for a cable modem via the cable modem termination system; and

a virtual data connection, for connecting the cable modem to the data network, wherein the virtual data connection includes sending data from the data network via the cable modem termination system over a downstream cable connection on a cable television network to a cable modem, and sending data to the data network from the cable modem through the telephony return access concentrator over an upstream telephony connection via the public switched telephone network.

19. The system of claim 18 wherein the plurality of network host interfaces are Internet Protocol interfaces.

20. The system of claim 18 wherein the data network is any of the Internet or an intranet.

21. The system of claim 18 wherein the network addresses are Internet Protocol addresses.

22. In a data-over-cable system with a plurality of cable modems connected to a cable modem termination system on a cable television network with a downstream cable connection, and the cable modems connected to a telephony remote access concentrator on a public switched telephone network with an upstream telephony connection, the cable modem termination system and telephony remote access concentrator connected to data network, a method of discovering network host interfaces, the method comprising the following steps:

creating a Dynamic Host Configuration Protocol discover message on a first cable modem, the Dynamic Host Configuration Protocol message having a first Internet Protocol address in a first message field for the downstream cable connection from the cable modem termination system;

sending the Dynamic Host Configuration Protocol discover message from the first cable modem on the upstream telephony connection to telephony remote access concentrator;

broadcasting the Dynamic Host Configuration Protocol discover message from the telephony remote access concentrators to a plurality of Dynamic Host Configuration Protocol proxies associated with the telephony remote access concentrator using the first Internet Protocol address from the first field in the Dynamic Host Configuration Protocol discover message;

forwarding the Dynamic Host Configuration Protocol message from the plurality of Dynamic Host Configuration Protocol proxies to a plurality of Dynamic Host Configuration servers associated with a plurality of network host interfaces available on the cable modem termination system using the first Internet Protocol address from the first field in the Dynamic Host Configuration Protocol discover message;

creating one or more Dynamic Host Configuration Protocol offer messages on one or more of the plurality of Dynamic Host Configuration protocol servers in response to the Dynamic Host Configuration protocol discover message, wherein the Dynamic Host Configuration offer messages include a second Internet Protocol address available on the cable modem termination system for communicating with the third network;

forwarding the one or more Dynamic Host Configuration Protocol offer messages from one or more of the plurality of Dynamic Host Configuration protocol servers to the cable modem termination system using the first Internet Protocol address from the first field in the Dynamic Host Configuration Protocol discover message;

forwarding the one or more Dynamic Host Configuration Protocol offer messages received on the cable modem termination system from the cable modem termination system over the downstream cable connection to the first cable modem; and

selecting on the first cable modem, an Internet Protocol address from one of the Dynamic Host Configuration Protocol offer messages, thereby establishing a virtual connection from the data network to the first cable modem,

wherein the virtual connection includes receiving data from the data network on the second Internet Protocol address on the cable modem termination system, and sending the data from the cable modem termination system over the downstream cable connection to the first cable modem, and sending data including the second Internet Protocol address to the data network from the first cable modem through the telephony return access concentrator over an upstream telephony connection via the public switched telephone network.

23. A computer readable medium having stored therein instructions for causing a central processing unit to execute the method of claim 22.

24. The method of claim 22 wherein the data network is any of the Internet or an intranet.

25. The method of claim 22 wherein the first message field for the downstream cable connection from the cable modem termination system includes an Internet Protocol address for an individual downstream channel on the downstream cable connection.