Technique for content delivery over the internet

• US 20020169890A1
• Filed: 05/08/2001
• Published: 11/14/2002
• Est. Priority Date: 05/08/2001
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Wang, Steve Y., Vernick, Michael, Hofmann, Markus, Beaumont, Leland R.
• Granted Patent: US 6,959,333 B2
• Time in Patent Office: Days
• US Class Current: 709/245
• CPC Class Codes: H04L 61/4511 using domain name system [DNS]
• 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
• CPC Class Codes: H04L 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1038 Load balancing arrangements to avoid a single path through a load balancer

Abstract

A content delivery system for a content provider that comprises at least two content delivery servers for delivering contents, a preference database for storing an estimated distance between each of the at least two content delivery servers and a client, and a content provider domain name server for mapping the name of the content provider to the at least two content delivery servers and selecting one of the content delivery servers to deliver the content, that has a shortest estimated distance to the client in the preference database.

Claims

1. A server for responding to a request to map an input name into an address from a requester, the server comprising:

(a) a receiver for receiving the request; and

(b) a processor for selecting one of the working addresses mapped to the input name, that is best to the requester.

2. The server of claim 1 wherein the best working address is one that is closest to the requester.

3. The server of claim 2 further comprising a memory for storing a mapping database for mapping a name into an address wherein at least one name is mapped to more than one address.

4. The server of claim 3 wherein the memory stores a preference database for assigning a preference number associated with an address and a requester identifier wherein at least one requester identifier is associated with more than one address and one preference number, and wherein the processor selects one of the mapped addresses based on preference numbers associated with the requester identifier in the preference database.

5. The server of claim 4 wherein the processor selects the mapped address having the highest preference number.

6. The server of claim 5 wherein if the processor has selected the same mapped address for a pre-defined number of times and there is one mapped address that does not have a corresponding preference number in the preference table, the processor selects the mapped address that does not have a corresponding preference number in the preference table.

7. The server of claim 4 wherein if the corresponding preference number for one mapped address is not present in the preference table, the processor selects that mapped address.

8. The server of claim 4 wherein the processor selects one of the mapped addresses having a corresponding preference number exceeding a threshold.

9. The server of claim 4 wherein a preference number is an estimated distance between the address and the requester associated with the preference number.

10. The server of claim 4 wherein the processor dynamically assigns a time-to-live (TTL) value to the selected mapped address associated with the requester identifier.

11. The server of claim 4 wherein the processor assigns a TTL value to the selected address associated with the requester identifier before the selected mapped address is selected.

12. The server of claim 4 wherein the requester identifier is a prefix of an address identifying the requester.

13. The server of claim 4 wherein the requester identifier is an address identifying the requester.

14. The server of claim 4 wherein the preference number is entered manually.

15. The server of claim 1 wherein the best working address is one that has the fewest number of lost packets.

16. The server of claim 1 wherein the best working address is one that has the fewest number of connections.

17. The server of claim 1 wherein the best working address is determined according to a function of at least two factors.

18. The server of claim 17 wherein the at least two factors are:

distance to the requester from each mapped working address, number of lost packets at each mapped working address, number of connections at each mapped working address, and a pre-assigned number for each mapped working address.

20. The computer program product of claim 19 wherein the selecting program code segment selects one of the retrieved mapped addresses having the highest retrieved preference number.

21. The computer program product of claim 19 further comprising an assigning program code segment for dynamically assigning a time-to-live (TTL) value to each entry in the preference database associated with the requester identifier.

22. The computer program product of claim 19 further comprising an assigning program code segment for dynamically assigning a TTL value to the entry in the preference database associated with the selected retrieved mapped address.

23. The computer program product of claim 22 wherein the assigning program code segment dynamically assigns a TTL value to an entry in the preference database table as a function of the preference number in that entry.

24. The computer program product of claim 22 wherein the assigning program code segment assigns a TTL value to an entry in the preference database table directly related to the preference number of that entry.

25. A computer program product of claim 19 wherein a preference number associated with a retrieved mapped address is an estimated distance between the retrieved mapped address and the requester.

27. The method of claim 26 wherein a retrieved mapped address with the highest retrieved preference number is selected.

28. The method of claim 26 wherein a preference number associated with a retrieved mapped address is an estimated distance between the retrieved mapped address and the requester.

29. The method of claim 26 further comprising the step of assigning a time-to-live (TTL) value to the entry in the preference table associated with each retrieved mapped address and the requester identifier.

30. The method of claim 26 further comprising the step of assigning a time-to-live (TTL) value to the entry in the preference table associated with the selected retrieved mapped address and the requester identifier.

31. The method of claim 30 where in the response further comprising the assigned TTL value.

19. A computer program product having a computer readable medium having computer program logic recorded thereon for mapping an input name into an address upon a request from a requester, the computer program product comprising:

(a) a receiving program code segment for causing a computer to receive the input name from the request;

(b) a mapping program code segment for causing the computer to map the input name against a mapping database for mapping a name to an address wherein at least one name is mapped to more than one address, the mapping program code segment also for causing the computer to retrieve from the mapping database all addresses mapped to the input name;

(c) a selecting program code segment for causing the computer to retrieve a preference number from a preference database associated with each retrieved mapped address and the input name, each entry of the preference database comprising an address, a requester identifier, and a preference number, wherein the requester is identified by the requester identifier and at least one requester identifier is listed in more than one entry, the selecting program code segment also for causing the computer to select one of the retrieved mapped addresses based on the retrieved preference numbers; and

(d) a returning program code segment for causing the computer to return to the requester a response comprising the selected retrieved mapped address.

26. A method for mapping an input name into an address upon request from a requester, the method comprising the steps of:

(a) retrieving from a mapping table all addresses mapped to the input name, each entry in the mapping table mapping a name to an address wherein at least one name is mapped to more than one address;

(b) retrieving from a preference table a preference number associated with each retrieved mapped address and the input name, each entry of the preference table comprising an address, a requester identifier, and a preference number, wherein at least one requester identifier is listed in more than one entry;

(c) selecting one of the retrieved mapped addresses based on the retrieved preference numbers; and

(d) returning a response comprising the selected address.

32. A system for delivering content from a content provider identified by a name to a client upon request from the client, the request comprising the name identifying the content provider, the system comprising:

(a) at least two content delivery servers for delivering the content, each content delivery server identified by a different address;

(b) a map retriever for mapping the name identifying the content provider to all addresses identifying the at least two content delivery servers, and

(c) a selector for selecting one of the mapped addresses that is closest to the requesting client to deliver the content.

33. The system of claim 32 wherein the selector further comprises a preference database for storing a preference number associated with the address identifying each of the at least two content delivery servers and the client.

34. The system of claim 33 wherein the selector retrieves from the preference database a preference number associated with each mapped address and the client and selecting one of the mapped addresses based on the retrieved preference numbers.

35. The system of claim 34 wherein the selector selects one of the mapped addresses, that has the highest retrieved preference number.

36. The system of claim 32 wherein a preference number associated with an address identifying a content delivery server and the client is an estimated distance between the content delivery server and the client.

37. The system of claim 36 wherein an estimated distance associated with an address identifying a content delivery server and the client is measured during a three-way handshake between the client and the content delivery server.

38. The system of claim 32 further comprising at least one content providing server for providing the content to the at least two content delivery servers.

39. The system of claim 38 wherein the at least two content delivery servers cache the content from the at least one content providing server.

40. The system of claim 32 further comprising means for dynamically assigning the selected content delivery server a time-to-live (TTL) value.