Selecting network address offered by a plurality of servers based on server identification information

• US 7,200,678 B1
• Filed: 09/04/2002
• Issued: 04/03/2007
• Est. Priority Date: 09/04/2002
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Malhotra, Pankaj, Bettadahalli, Sundar
• Primary Examiner(s): Lin; Wen-Tai
• Application Number:
  US10/235,114
• Time in Patent Office: 1,672 Days
• Field of Search: None
• US Class Current: 709/245
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]

Abstract

A method of dynamically obtaining a network address for a client includes transmitting a request for a network address. A plurality of network address offers can be received from a plurality of servers in response to the request. One of the plurality of offers can then be selected by the client using information contained in one or more of the offers. In one embodiment, a network comprises a client configured to dynamically obtain a network address from one of a plurality of servers. The client sends a discover message including a client identifier to the network. The servers receive the discover message and respond with offers including proposed network addresses. One or more of the offers further include a server identifier. The client preferably only accepts an offer containing an appropriate server identifier.

Claims

1. A method of obtaining a network address for a client, comprising:

transmitting a request for a network address, where the request contains client identification information;

configuring only a certain server or class of servers to recognize the client identification information in the request and to respond with a corresponding offer signal including server identification information responsive to the client identification information;

receiving a plurality of network address offers from a plurality of servers including the certain server and the class of servers, where at least one of the offers is the offer signal including the server identification information; and

selectively accepting the offer signal including the server identification information, wherein the client identification information is a client class identifier provided in a vendor class identifier field in the request and wherein the server identification information is a server class identifier provided in a vendor specific information field of the offer.

2. A method according to claim 1, wherein the request is a Dynamic Host Confirmation Protocol (DHCP) request and wherein the offers are DHCP offers.

3. A method according to claim 2, wherein server identification information is included in a vendor specific information field of the DHCP offer.

4. A method according to claim 3, wherein the server identification information is included in tag “

66”

within option field “

43”

of the vendor specific information field of the DHCP offer.

5. A method according to claim 2, further comprising including the information used in selecting the offer in one or more tags in the DHCP offer.

6. A method according to claim 2, wherein selectively accepting one of the plurality of DHCP offers comprises accepting an offer from a server providing predetermined server identification information in its DHCP offer.

7. A network device comprising:

an output port configured to transmit a request for a network address, the request comprising a network device identifier that identifies a type of network device making the request;

an input port configured to receive a plurality of offers to establish a network address from a plurality of servers, wherein at least one of the offers includes a server identifier identifying a type of server configured to recognize the client identifier in the request and encode the server identifier in the at least one offer; and

a processing unit configured to accept the at least one offer based on the server identifier.

8. A device according to claim 7, wherein the device is a client, and wherein the request comprises a Dynamic Host Confirmation Protocol (DHCP) discover request having a client identifier.

9. A device according to claim 8, wherein the client identifier is provided in a vendor class identifier field in the DHCP discover request.

10. A device according to claim 8, wherein one or more server identifiers are provided in a vendor specific information field of a corresponding DHCP offer.

11. A device according to claim 8, wherein the request for a network address comprises a Dynamic Host Confirmation Protocol (DHCP) discover request having a client identifier embedded therein, and wherein the offer comprises a DHCP offer having a server identifier embedded therein.

12. A method of selectively accepting a network address offer, said method comprising:

transmitting a network address request signal from a client, where the request contains client identification information identifying a type of client;

configuring a certain server or class of servers to recognize the client identification information in the request and to respond with an offer including server identification information identifying a type of client;

responding to the network address request signal with a plurality of offers from a plurality of servers, wherein at least one of the offers is the offer including the server identification information;

distinguishing among the plurality of offers in the client according to the server identification information; and

selectively accepting the at least one offer based on the server identification information contained in the offer to establish a network address for the client.

13. A method according to claim 12, wherein the network address request signal comprises a Dynamic Host Confirmation Protocol (DHCP) discover request having a DHCP client identifier.

14. A method according to claim 13, further comprising configuring one or more of the servers to recognize the DHCP client identifier in the discover request.

15. A method according to claim 12, wherein selectively accepting one of the offers comprises accepting a DHCP offer containing an appropriate server identifier.

16. An electronic medium containing code for obtaining a network address for a client, said code, when executed, causing a computer to:

transmit a request for a network address from a client, wherein the request includes client identification information;

configure a certain server or class of servers to recognize the client identification information in the request and to respond with an offer including server identification information;

receive a plurality of network address offers from a plurality of servers into the client, wherein at least one of the offers is the offer including the server identification information; and

selectively accepting the offer including the server identification information, wherein the client identification information is a client class identifier provided in a vendor class identifier field in the request and wherein the server identification information is a server class identifier provided in a vendor specific information field of the offer.

17. A device for obtaining a network address for a client, comprising:

means for transmitting a request for a network address, where the request includes client identification information;

means for configuring a certain server or class of servers to recognize the client identification information in the request and to respond to the request with an offer including server identification information;

means for receiving a plurality of network address offers from a plurality of servers, wherein at least one of the offers is the offer including server identification information; and

means for selectively accepting the at least one offer including the server identification information.