Content delivery and global traffic management network system

• US 20020052942A1
• Filed: 07/19/2001
• Published: 05/02/2002
• Est. Priority Date: 07/19/2000
• Status: Active Grant

• Current Assignee: Akamai Technologies, Inc.
• Original Assignee: Speedera Networks, Inc.
• Inventors: Gupta, Ajit K., Swildens, Eric Sven-Johan, Day, Richard David
• Granted Patent: US 6,754,699 B2
• Time in Patent Office: Days
• US Class Current: 709/223
• CPC Class Codes: G06F 2209/5016 Session
• CPC Class Codes: G06F 9/505 considering the load
• CPC Class Codes: H04L 12/14 Charging , metering or billing arrangements for data wireline or wireless communications
• CPC Class Codes: H04L 41/5029 Service quality level-based billing, e.g. dependent on measured service level customer is charged more or less
• CPC Class Codes: H04L 41/5064 Customer relationship management
• CPC Class Codes: H04L 41/5083 wherein the managed service relates to web hosting
• CPC Class Codes: H04L 41/509 wherein the managed service relates to media content delivery, e.g. audio, video or TV
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/0829 Packet loss
• CPC Class Codes: H04L 43/0852 Delays
• CPC Class Codes: H04L 43/12 Network monitoring probes
• CPC Class Codes: H04L 43/55 Testing of service level quality, e.g. simulating service usage
• 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 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• CPC Class Codes: H04L 67/10015 Access to distributed or replicated servers, e.g. using brokers
• CPC Class Codes: H04L 67/1006 with static server selection, e.g. the same server being selected for a specific client
• 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 67/1021 : based on client or server locations
• CPC Class Codes: H04L 67/1027 : Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/1034 : Reaction to server failures by a load balancer
• CPC Class Codes: H04L 67/1038 : Load balancing arrangements to avoid a single path through a load balancer
• CPC Class Codes: H04L 67/1095 : Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/142 : Managing session states for stateless protocols; Signalling session states; State transitions; Keeping-state mechanisms
• CPC Class Codes: H04L 67/289 : Intermediate processing functionally located close to the data consumer application, e.g. in same machine, in same home or in same sub-network
• CPC Class Codes: H04L 67/56 : Provisioning of proxy services store-and-forward switching systems in data switching networks H04L12/54
• CPC Class Codes: H04L 67/5681 : Pre-fetching or pre-delivering data based on network characteristics
• CPC Class Codes: H04L 67/5682 : Policies or rules for updating, deleting or replacing the stored data
• CPC Class Codes: H04L 69/329 : in the application layer [OSI layer 7]

Abstract

A content delivery and global traffic management network system provides a plurality of caching servers connected to a network. The caching servers host customer content that can be cached and stored, and respond to requests for Web content from clients. If the requested content does not exist in memory or on disk, it generates a request to an origin site to obtain the content. A DNS Server (SPD) load balances network requests among customer Web servers and directs client requests for hosted customer content to the appropriate caching server which is selected by choosing the caching server that is closest to the user, is available, and is the least loaded. SPD also supports persistence and returns the same IP addresses, for a given client. The entire Internet address space is broken up into multiple zones. Each zone is assigned to a group of SPD servers. If an SPD server gets a request from a client that is not in the zone assigned to that SPD server, it forwards the request to the SPD server assigned to that zone. Servers write information about the content delivered to log files that are picked up by a log server.

Claims

1. A process for a content delivery and global traffic management network, comprising the steps of:

providing a plurality of caching servers connected to said network;

wherein said caching servers host customer content that can be cached and stored;

wherein said caching servers respond to requests for said hosted customer content;

providing traffic management means for load balancing network requests among customer Web servers;

wherein said traffic management means directs client requests for hosted customer content to the appropriate caching server; and

wherein said hosted customer content includes, but is not limited to;

images, video, text, and/or software.

2. The process of claim 1, further comprising the steps of:

providing at least one DNS server; and

wherein said traffic management means is resident on said DNS server.

3. The process of claim 2, wherein said DNS server returns the same IP addresses for requests from a given client if the connection is a persistent one.

4. The process of claim 3, wherein said DNS server maintains a table containing the IP address given out for a given hostname to a client;

wherein said table is created dynamically in response to incoming requests and is synchronized across all the DNS servers responsible for a given zone; and

wherein if the same client tries to resolve a given hostname against a different DNS server in the future, said different DNS server will give the same result.

5. The process of claim 2, wherein the entire network address space is broken up into multiple zones and each zone is assigned to a group of DNS servers.

6. The process of claim 5, wherein if a DNS server gets a request from a client that is not in the zone assigned to that DNS server, it forwards the request to the DNS server assigned to that zone.

7. The process of claim 5, wherein DNS servers need to keep latency and persistence information only for the clients that fall in the zone assigned to the DNS server.

8. The process of claim 7, wherein the DNS servers only need to synchronize the persistence information with the DNS servers responsible for that zone, not all the DNS servers in the network.

9. The process of claim 5, wherein when a DNS server has to forward the DNS request to DNS servers in another zone, it selects the server with the best (lowest) latency value thereby performing dynamic load balancing between the DNS servers in the same zone.

10. The process of claim 2, further comprising the step of:

providing hostname mapping means resident on a DNS server for dynamically mapping hostname entries to second tier domain names to increase the number of DNS servers in said network to more than the maximum allowed for .com domains.

11. The process of claim 2, wherein a customer either delegates a DNS name to said DNS server using a CNAME or by directly delegating the domain or is assigned a host domain name.

12. The process of claim 11, wherein some portion of the customer'"'"'s Web site is associated with said assigned host domain name.

13. The process of claim 11, wherein when the host server for said assigned host domain name gets a hit for content it does not contain, it will hit the appropriate content on the customer'"'"'s Web site to pick up and store that content, otherwise, said host server fulfills the hit from its cache.

14. The process of claim 1, wherein said traffic management means selects the appropriate caching server by choosing the caching server that is closest to the user, is available, and is the least loaded.

15. The process of claim 1, wherein said caching servers make requests back to the origin customer server site at specified intervals to check to see if the content said caching server has cached is fresh.

16. The process of claim 1, wherein said caching servers look at expiry headers in the HTTP content it retrieves from the origin customer server site to ensure freshness.

17. The process of claim 1, wherein every server in said network that needs configuration information has a copy of the appropriate current configuration file;

wherein the configuration file that a server receives contains all the configuration information for the particular portion of the network; and

wherein the data contained in the configuration file includes, but is not limited to;

a list of servers allowed to change the configuration, a list of domains the network is responsible for, a list of services the machines in each POP supports, and/or a list of probes that perform latency checks at each POP.

18. The process of claim 17, wherein a system administrator can, at any time, push a new configuration file to all machines that need it.

19. The process of claim 1, wherein if the requested content does not exist in memory or on disk on said designated caching server, said designated cache server generates a request to a customer Web server to obtain said requested content and store it in memory or on disk.

20. The process of claim 1, further comprising the steps of:

providing a log server; and

providing a database server.

21. The process of claim 20, wherein caching servers write information about any content delivered to log files;

and wherein said log files that are picked up and maintained by said log server.

22. The process of claim 20, wherein said log server collects log files from the appropriate servers in said network;

and wherein said log files are then processed by said log server and sent to said database server.

23. The process of claim 22, wherein said database server stores said log files generated by said log servers as tables for later extraction for purposes such as cache hit statistics, billing etc.

24. The process of claim 20, further comprising the step of:

providing log file distributors located on select servers within said network;

wherein said log file distributors determine the log server IP address to send said log files to by querying said DNS server;

wherein if multiple IP addresses are returned to said log file distributors, any random IP address will be selected from said multiple IP addresses;

wherein if the connection to the selected IP address fails, then all other IP addresses in said multiple IP addresses will be tried in sequence until a connection is established or all IP addresses have been tried; and

wherein upon successful connection, the log file distributor compresses the log file and sends it to said log server.

26. The method of claim 25, further comprising the steps of:

providing at least one DNS server; and

wherein said traffic management means is resident on said DNS server.

27. The method of claim 26, wherein said DNS server returns the same IP addresses for requests from a given client if the connection is a persistent one.

28. The method of claim 27, wherein said DNS server maintains a table containing the IP address given out for a given hostname to a client;

wherein said table is created dynamically in response to incoming requests and is synchronized across all the DNS servers responsible for a given zone; and

wherein if the same client tries to resolve a given hostname against a different DNS server in the future, said different DNS server will give the same result.

29. The method of claim 26, wherein the entire network address space is broken up into multiple zones and each zone is assigned to a group of DNS servers.

30. The method of claim 29, wherein if a DNS server gets a request from a client that is not in the zone assigned to that DNS server, it forwards the request to the DNS server assigned to that zone.

31. The method of claim 29, wherein DNS servers need to keep latency and persistence information only for the clients that fall in the zone assigned to the DNS server.

32. The method of claim 31, wherein the DNS servers only need to synchronize the persistence information with the DNS servers responsible for that zone, not all the DNS servers in the network.

33. The method of claim 29, wherein when a DNS server has to forward the DNS request to DNS servers in another zone, it selects the server with the best (lowest) latency value thereby performing dynamic load balancing between the DNS servers in the same zone.

34. The method of claim 26, further comprising the step of:

providing hostname mapping means resident on a DNS server for dynamically mapping hostname entries to second tier domain names to increase the number of DNS servers in said network to more than the maximum allowed for .com domains.

35. The method of claim 26, wherein a customer either delegates a DNS name to said DNS server using a CNAME or by directly delegating the domain or is assigned a host domain name.

36. The method of claim 35, wherein some portion of the customer'"'"'s Web site is associated with said assigned host domain name.

37. The method of claim 35, wherein when the host server for said assigned host domain name gets a hit for content it does not contain, it will hit the appropriate content on the customer'"'"'s Web site to pick up and store that content, otherwise, said host server fulfills the hit from its cache.

38. The method of claim 25, wherein said traffic management means selects the appropriate caching server by choosing the caching server that is closest to the user, is available, and is the least loaded.

39. The method of claim 25, wherein said caching servers make requests back to the origin customer server site at specified intervals to check to see if the content said caching server has cached is fresh.

40. The method of claim 25, wherein said caching servers look at expiry headers in the HTTP content it retrieves from the origin customer server site to ensure freshness.

41. The method of claim 25, wherein every server in said network that needs configuration information has a copy of the appropriate current configuration file;

wherein the configuration file that a server receives contains all the configuration information for the particular portion of the network; and

wherein the data contained in the configuration file includes, but is not limited to;

a list of servers allowed to change the configuration, a list of domains the network is responsible for, a list of services the machines in each POP supports, and/or a list of probes that perform latency checks at each POP.

42. The method of claim 41, wherein a system administrator can, at any time, push a new configuration file to all machines that need it.

43. The method of claim 25, wherein if the requested content does not exist in memory or on disk on said designated caching server, said designated cache server generates a request to a customer Web server to obtain said requested content and store it in memory or on disk.

44. The method of claim 25, further comprising the steps of:

providing a log server; and

providing a database server.

45. The method of claim 44, wherein caching servers write information about any content delivered to log files;

and wherein said log files that are picked up and maintained by said log server.

46. The method of claim 44, wherein said log server collects log files from the appropriate servers in said network;

and wherein said log files are then processed by said log server and sent to said database server.

47. The method of claim 46, wherein said database server stores said log files generated by said log servers as tables for later extraction for purposes such as cache hit statistics, billing etc.

48. The method of claim 44, further comprising the step of:

providing log file distributors located on select servers within said network;

wherein said log file distributors determine the log server IP address to send said log files to by querying said DNS server;

wherein if multiple IP addresses are returned to said log file distributors, any random IP address will be selected from said multiple IP addresses;

wherein if the connection to the selected IP address fails, then all other IP addresses in said multiple IP addresses will be tried in sequence until a connection is established or all IP addresses have been tried; and

wherein upon successful connection, the log file distributor compresses the log file and sends it to said log server.

25. A program storage medium readable by a computer, tangibly embodying a program of instructions executable by the computer to perform method steps for a content delivery and global traffic management network, comprising the steps of:

providing a plurality of caching servers connected to said network;

wherein said caching servers host customer content that can be cached and stored;

wherein said caching servers respond to requests for said hosted customer content;

providing traffic management means for load balancing network requests among customer Web servers;

wherein said traffic management means directs client requests for hosted customer content to the appropriate caching server; and

wherein said hosted customer content includes, but is not limited to;

images, video, text, and/or software.