Methods and apparatus for content server selection

• US 7,062,562 B1
• Filed: 04/11/2001
• Issued: 06/13/2006
• Est. Priority Date: 04/11/2001
• Status: Expired due to Fees

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Baker, Frederick, Lueckenhoff, Bruce
• Primary Examiner(s): Etienne, Ario
• Assistant Examiner(s): Osman, Ramy M
• Application Number:
  US09/833,387
• Time in Patent Office: 1,889 Days
• Field of Search: 709/203, 709/223, 709/224, 709225-229, 709/232, 370/471, 370/472, 370/474, 370/476, 370/238, 718/105
• US Class Current: 709/227
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• CPC Class Codes: H04L 61/4541 Directories for service discovery
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/1008 based on parameters of servers, e.g. available memory or workload monitoring of computer activity G06F11/30
• CPC Class Codes: H04L 67/101 based on network conditions

Abstract

Methods and apparatus providing information about characteristics associated with a network are described. A network node associated with a client for selecting a server that can best provide content to a client transmits a request for a response. A plurality of content servers or content routing agents receive requests corresponding to the request from the network node associated with the client. The content servers provide a response and fragment and/or pad datagrams associated with the response. The content servers transmit these fragmented and/or padded datagrams to the network node associated with the client. The network node associated with the client can reassemble and/or trim the received datagrams and identify as optimal the server that first completes transmission of the response.

Claims

1. A method for providing information for selecting a content server to a network node associated with a client, the method comprising:

receiving a request for a response, wherein the request corresponds to a message transmitted by a network node associated with a client for selecting a content server;

providing a response datagram, the response datagram associated with the received request, wherein network requirements allow transmission of the response datagram to the network node without padding the response datagram;

providing a padded response datagram, wherein the padded response datagram is obtained by padding the response datagram with an arrangement of bits; and

transmitting the padded response datagram to the network node associated with the client for selecting a content server wherein reception of the padded response datagram by the network node provides information for selecting a content server.

2. The method of claim 1, wherein the request is a Boomerang Control Protocol message.

3. The method of claim 1, wherein the response is a DNS reply.

4. The method of claim 1, wherein the bits are randomly generated.

5. The method of claim 1, wherein the network node associated with the client for selecting a content server is a local domain name server.

6. A method for providing information associated with a network for selecting a content server, the method comprising:

receiving a request from the server selection system for a response message;

providing a response datagram, the response datagram corresponding to the response message, wherein the response datagram is associated with a network layer length, a transport layer length, and a network layer header length;

providing an altered response datagram, wherein the network layer length is greater than the sum of the transport layer length and the network layer header length;

transmitting the altered response datagram to a node responsible for selecting a content server, wherein receipt of the altered response datagram provides information on network characteristics to a server selection system.

7. The method of claim 6, wherein the request is a Boomerang Control Protocol message.

8. The method of claim 7, wherein the response is a DNS Reply.

9. The method of claim 6, wherein the altered response datagram is padded with data.

10. The method of claim 9, wherein the data is randomly generated.

11. A computer program product comprising a machine readable medium on which is provided program instructions for providing network information to a network node associated with a client, the computer program product comprising:

computer code for receiving a request for a response, wherein the request corresponds to a message transmitted by the network node associated with a client for selecting a content server;

computer code for providing a response datagram, the response datagram associated with the received request, wherein network requirements allow transmission of the response datagram to the network node without padding the response datagram;

computer code for providing a padded response datagram, wherein the padded response datagram is obtained by padding the response datagram with an arrangement of bits; and

computer code for transmitting the padded response datagram to the network node associated with the client for selecting a content server wherein reception of the padded response datagram by the network node provides information for selecting a content server.

12. The computer program product of claim 11, wherein the request is a Boomerang Control Protocol message.

13. The computer program product of claim 12, wherein the response is a DNS reply.

14. The computer program product of claim 13, wherein reception of the padded response datagram by the network node provides bandwidth availability information to the network node associated with the client.

15. The computer program product of claim 11, wherein the network layer length of the response datagram is increased while the transport layer length field is unmodified.

16. The computer program product of claim 11, wherein the arrangement of bits is randomly generated.

17. An apparatus for providing network information for selecting a content server to a network node associated with a client, the apparatus comprising:

memory;

an input interface for receiving a request for a response, wherein the request corresponds to a message transmitted by the network node associated with a client for selecting a content server;

one or more processors coupled with the memory, the processors configured to provide a response datagram, the response datagram corresponding to the received request, wherein the response datagram can be transmitted without padding and wherein the processors are configured to provide a padded response datagram, the padded response datagram obtained by padding the response datagram with an arrangement of bits;

an output interface for transmitting the padded response datagram to the network node associated with the client wherein reception of the padded response datagram by the network node provides information for selecting a content server.

18. The apparatus of claim 17, wherein the network node associated with the client is a local domain name server.

19. The apparatus of claim 17, wherein the network node associated with the client is a server selection system.

20. The apparatus of claim 17, wherein the request is a Boomerang Control Protocol message.

21. The apparatus of claim 17, wherein the response is a DNS Reply.

22. The apparatus of claim 17, wherein the padded response datagram can be trimmed to form a DNS Reply.

23. The apparatus of claim 17, wherein the response datagram correspond to a network layer length field and a transport layer let field.

24. The apparatus of claim 23, wherein the network layer length field is increased while the transport layer length field is unmodified.

25. The apparatus of claim 17, wherein the arrangement of bits is randomly generated.

26. A apparatus for providing information for selecting a content server to a network node associated with a client, the apparatus comprising:

means for receiving a request for a response, wherein the request corresponds to a message transmitted by a network node associated with a client for selecting a content server;

means for providing a response datagram, the response datagram associated with the received request, wherein the response datagram can be transmitted without padding;

means for providing a padded response datagram, wherein the padded response datagram is obtained by padding the response datagram with an arrangement of bits; and

means for transmitting the padded response datagram to the network node associated with the client for selecting a content server wherein reception of the padded response datagram by the network node provides information for selecting a content server.

27. The apparatus of claim 26, wherein the response datagram corresponds to a network layer length field and a transport layer length field.

28. The apparatus of claim 27, wherein the network layer length field is increased while the transport layer length field is unmodified.

29. The apparatus of claim 26, wherein the arrangement of bits is randomly generated.