Computed client identifier in DHCP

• US 7,757,000 B1
• Filed: 12/14/2006
• Issued: 07/13/2010
• Est. Priority Date: 12/14/2006
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Brown, James Timothy, Kinnear, Kenneth E. Jr., Littlefield, Joshua B.
• Primary Examiner(s): Maung; Zarni
• Application Number:
  US11/638,744
• Time in Patent Office: 1,307 Days
• Field of Search: 709/230, 709/245, 709217-218, 709/250
• US Class Current: 709/245
• 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 performed by a DHCP server. The method involves receiving a transformation instruction from a user or other command source. The method further involves in response to receiving a request from a client for a network address, applying the transformation instruction to the client request to generate a client identity pattern; and assigning a network address from a pool of network addresses to the client based on the client identity pattern. Apparatus for use in practicing the method are also claimed.

Claims

1. A method comprising:

receiving a transformation instruction from a command source;

in response to receiving a request from a client for a network address, applying the transformation instruction to the client request to generate a client identity pattern; and

assigning a network address from a pool of network addresses to the client based on the client identity pattern.

2. A method as in claim 1:

wherein the request from the client is a Dynamic Host Configuration Protocol (DHCP) packet received over a network;

wherein applying the transformation instruction to the client request to generate a client identity pattern comprises reading the contents of the DHCP packet and transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet, the output of the transformation being the client identity pattern, the contents of the DHCP packet remaining unchanged by the application of the transformation; and

wherein the network address is an IP address.

3. A method as in claim 2:

wherein receiving a transformation instruction from a command source comprises receiving an executable expression from the command source; and

wherein transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet comprises executing the executable expression on the DHCP packet.

4. A method as in claim 2:

wherein the DHCP packet includes information stored in fields;

wherein the transformation instruction identifies a series of fields to be extracted from the DHCP packet and a function on the contents of the series of fields; and

wherein transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet comprises executing the function on the contents of the series of fields within the DHCP packet to form the client identity pattern.

5. A method as in claim 4 wherein the function is to concatenate the contents of the fields in the order presented.

6. A method as in claim 1:

wherein the client is a first Dynamic Host Configuration Protocol (DHCP) client device;

wherein the request from the client is a DHCP packet received over a network; and

wherein the method further comprises;

after the first DHCP client device has operated for an amount of time using the assigned network address, receiving another client request for a network address from a second DHCP client device that has replaced the first DHCP client device;

in response to receiving the other client request, applying the transformation instruction to the other client request to generate a second client identity pattern, the second client identity pattern being identical to the first client identity pattern; and

assigning the network address to the other DHCP client device based on the second client identity pattern.

7. A method as in claim 1 wherein:

the client is a first machine of a plurality of machines coupled to a multi-port router, the plurality of machines comprising an assembly line, the multi-port router having a plurality of network ports;

each of the plurality of machines couples to the multi-port router by plugging into a network port of the plurality of network ports of the router;

the request from the client is a Dynamic Host Configuration Protocol (DHCP) Discover packet having a field inserted by a relay agent of the multi-port router, the field including an identification of the multi-port router and an indication of which network port the client is plugged into;

applying the transformation instruction to the client request includes concatenating the identification of the multi-port router and the indication of which network port the client is plugged into; and

assigning the network address from the pool of network addresses to the client based on the client identity pattern includes assigning the network address of a machine of the assembly line expected to be plugged into the multi-port router at the network port which the client is plugged into.

8. An apparatus comprising:

a user interface configured to receive a transformation instruction from a user;

a network interface configured to receive a request from a client for a network address;

logic configured to;

in response to receiving a request from a client for a network address, apply the transformation instruction to the client request to generate a client identity pattern, the application of the transformation instruction to the client request not modifying the client request; and

assign a network address from a pool of network addresses to the client based on the client identity pattern.

9. An apparatus as in claim 8:

wherein the request from the client is a Dynamic Host Configuration Protocol (DHCP) packet received over a network;

wherein the logic configured to apply the transformation instruction to the client request to generate a client identity pattern comprises logic configured to read the contents of the DHCP packet and transform the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet, the output of the transformation being the client identity pattern, the contents of the DHCP packet remaining unchanged by the application of the transformation; and

wherein the network address is an IP address.

10. An apparatus as in claim 9:

wherein the user interface configured to receive a transformation instruction from a user is configured to receive an executable expression from the user; and

wherein the logic configured to transform the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet comprises logic configured to execute the executable expression on the DHCP packet.

11. An apparatus as in claim 9

wherein the DHCP packet includes information stored in fields;

and

wherein the transformation instruction identifies a series of fields to be extracted from the DHCP packet and a function on the contents of the series of fields; and

wherein the logic configured to transform the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet comprises logic configured to execute the function on the contents of the series of fields within the DHCP packet to form the client identity pattern.

12. An apparatus as in claim 11 wherein the function is to concatenate the contents of the fields in the order presented.

13. An apparatus as in claim 8

wherein the client is a first Dynamic Host Configuration Protocol (DHCP) client device;

wherein the request from the client is a DHCP packet received over a network; and

wherein the logic is further configured to;

after the first DHCP client device has operated for an amount of time using the assigned network address, receive another client request for a network address from a second DHCP client device that has replaced the first DHCP client device;

in response to receiving the other client request, apply the transformation instruction to the other client request to generate a second client identity pattern, the second client identity pattern being identical to the first client identity pattern; and

assign the network address to the other DHCP client device based on the second client identity pattern.

14. An apparatus as in claim 8 wherein:

the client is a first machine of a plurality of machines coupled to a multi-port router, the plurality of machines comprising an assembly line, the multi-port router having a plurality of network ports;

each of the plurality of machines couples to the multi-port router by plugging into a network port of the plurality of network ports of the router;

the request from the client is a Dynamic Host Configuration Protocol (DHCP) Discover packet having a field inserted by a relay agent of the multi-port router, the field including an identification of the multi-port router and an indication of which network port the client is plugged into;

the logic configured to apply the transformation instruction to the client request includes logic configured to concatenate the identification of the multi-port router and the indication of which network port the client is plugged into; and

the logic configured to assign the network address from the pool of network addresses to the client based on the client identity pattern includes logic configured to assign the network address of a machine of the assembly line expected to be plugged into the multi-port router at the network port which the client is plugged into.

15. An apparatus comprising:

means for receiving a transformation instruction from a command source;

a network interface configured to receive a request from a client for a network address;

means for;

in response to receiving a request from a client for a network address, applying the transformation instruction to the client request to generate a client identity pattern, the application of the transformation instruction to the client request not modifying the client request; and

assigning a network address from a pool of network addresses to the client based on the client identity pattern.

16. An apparatus as in claim 15:

wherein the request from the client is a Dynamic Host Configuration Protocol (DHCP) packet received over a network;

wherein the means for applying the transformation instruction to the client request to generate a client identity pattern comprises means for reading the contents of the DHCP packet and transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet, the output of the transformation being the client identity pattern, the contents of the DHCP packet remaining unchanged by the application of the transformation; and

wherein the network address is an IP address.

17. An apparatus as in claim 16:

wherein the means for receiving a transformation instruction from a command source includes means for receiving an executable expression from the command source; and

wherein the means for transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet includes means for executing the executable expression on the DHCP packet.

18. An apparatus as in claim 16

wherein the DHCP packet includes information stored in fields;

and

wherein the transformation instruction identifies a series of fields to be extracted from the DHCP packet and a function on the contents of the series of fields; and

wherein the means for transforming the contents of the DHCP packet by applying the transformation instruction to the contents of the DHCP packet includes means for executing the function on the contents of the series of fields within the DHCP packet to form the client identity pattern.

19. An apparatus as in claim 18 wherein the function is to concatenate the contents of the fields in the order presented.

20. An apparatus as in claim 15

wherein the client is a first Dynamic Host Configuration Protocol (DHCP) client device;

wherein the request from the client is a DHCP packet received over a network; and

wherein the apparatus further comprises means for;

after the first DHCP client device has operated for an amount of time using the assigned network address, receiving another client request for a network address from a second DHCP client device that has replaced the first DHCP client device;

in response to receiving the other client request, applying the transformation instruction to the other client request to generate a second client identity pattern, the second client identity pattern being identical to the first client identity pattern; and

assigning the network address to the other DHCP client device based on the second client identity pattern.

21. An apparatus as in claim 15 wherein:

the client is a first machine of a plurality of machines coupled to a multi-port router, the plurality of machines comprising an assembly line, the multi-port router having a plurality of network ports;

each of the plurality of machines couples to the multi-port router by plugging into a network port of the plurality of network ports of the router;

the request from the client is a Dynamic Host Configuration Protocol (DHCP) Discover packet having a field inserted by a relay agent of the multi-port router, the field including an identification of the multi-port router and an indication of which network port the client is plugged into;

the means for applying the transformation instruction to the client request includes means for concatenating the identification of the multi-port router and the indication of which network port the client is plugged into; and

the means for assigning the network address from the pool of network addresses to the client based on the client identity pattern includes means for assigning the network address of a machine of the assembly line expected to be plugged into the multi-port router at the network port which the client is plugged into.