Cable modem system

• US 6,651,092 B1
• Filed: 12/23/1999
• Issued: 11/18/2003
• Est. Priority Date: 12/24/1998
• Status: Expired due to Fees

• Current Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Original Assignee: Kabushiki Kaisha Toshiba (Toshiba Corporation)
• Inventors: Muraoka, Kazuhiko
• Primary Examiner(s): Thompson, Marc D.
• Application Number:
  US09/471,421
• Time in Patent Office: 1,426 Days
• Field of Search: 709/227, 709/228, 709/221, 709/245, 709/242, 709/220, 709/222, 709/250, 370/338, 370/340, 370/409, 370/475, 370/401, 710/10
• US Class Current: 709/220
• CPC Class Codes: H04L 61/5007 Internet protocol [IP] addresses
• CPC Class Codes: H04L 61/5038 for local use, e.g. in LAN or USB networks, or in a controller area network [CAN]
• CPC Class Codes: H04L 61/5053 Lease time; Renewal aspects

Abstract

A system and method are disclosed for managing an assignment of IP addresses in a cable modem system. According to the disclosed system and method, an IP address of a specific kind is assigned to a client according to the classification of the client. A private IP address is issued in case of the client being a cable modem and a global IP address is issued in other cases so that the number of global addresses needed in the cable modem system can be reduced.

Claims

1. A cable modem system, comprising:

at least one cable modem (CM);

at least one user computer connected to the cable modem;

a cable modem terminate system (CMTS);

a cable via which the at least one cable modem and the CMTS are connected; and

means coupled to the CMTS for assigning, in response to a request from a client, a private IP address to the client when the client is a cable modem and a global IP address to the client when the client is a user computer, said IP address assigning means including;

means for determining whether the request is a first request from the client,

means for issuing to the client, when the request is the first request, a temporary IP address having a term of validity of a sufficient duration to enable the IP address assigning means to determine whether or not the client is a cable modem before said term of validity expires, and

inquiring means for sending an inquiry, including a media access control (MAC) address of the client, to the CMTS to determine whether the client is a cable modem.

2. The system of claim 1, wherein the IP address assigning means includes means for dividing requests according to a number of requests from the same client before the request.

3. The system of claim 1, wherein the CMTS includes:

a CM information file; and

means for responding which determines if the client is cable modem using the CM information file in response to the inquiry from the inquiring means.

4. The system of claim 1, wherein the private and global IP addresses are nontemporary IP addresses.

5. A method for managing an assignment of IP addresses in a cable modem system, comprising the steps of:

a. issuing, by a client, a first request for an IP address to a server;

b. issuing, via the server, a temporary IP address to the client in response to the first request;

c. determining, via the server, whether the client is a cable modem after issuing the temporary IP address to said client;

d. issuing, by the client, a subsequent request for an IP address to the server; and

e. issuing, via the server and in response to the subsequent request, a non-temporary private IP address to the client when the client is determined to be a cable modem and a non-temporary global IP address to the client when the client is determined not to be a cable modem,

wherein step e. comprises;

establishing a threshold number;

issuing the non-temporary private or public IP address when the subsequent request is a request issued after issuance of the threshold number of requests by the client; and

issuing a temporary IP address to the client when the subsequent request is a request issued before said threshold number of requests are issued.

6. A method for managing an assignment of IP addresses in a cable modem system, comprising:

issuing, by a client, a first request for an IP address to a server;

issuing, via the server, a temporary IP address to the client in response to the first request;

determining, via the server, whether the client is a cable modem after issuing the temporary IP address to said client;

issuing, by the client, a subsequent request for an IP address to the server; and

issuing, via the server and in response to the subsequent request, a non-temporary private IP address to the client when the client is determined to be a cable modem and a non-temporary global IP address to the client when the client is determined not to be a cable modem,

wherein said issuing, via the server, a temporary IP address comprises issuing a temporary IP address having a term of validity of a sufficient duration to enable the server to determine whether or not the client is a cable modem before said term of validity expires.

7. The method of claim 6, further comprising checking how many requests were issued before the subsequent request from the client.

8. The method of claim 6, wherein determining whether the client is a cable modem comprises determining whether the client is a cable modem using a MAC address of the client.

9. The method of claim 6, wherein the subsequent request for an IP address is issued by the client before expiration of the term of validity of the temporary IP address.

10. An apparatus for assigning an IP address in response to a request from a client, comprising:

means for dividing requests according to the number of requests from the same client before the request;

means for issuing a temporary IP address when the request is a first request from the client;

means for issuing a nontemporary IP address when the request is a subsequent request from the client according to a classification of the client; and

means for inquiring as to whether the client is a cable modem using a media access control (MAC) address of the client,

wherein the means for issuing a nontemporary IP address issues a private IP address when the client is a cable modem and issues a global address when the client is not a cable modem, and wherein the temporary IP address has a term of validity of a sufficient duration to enable the inquiring means to determine whether or not the client is a cable modem before said term of validity expires.