Intelligent demand driven recognition of URL objects in connection oriented transactions

• US 7,228,350 B2
• Filed: 08/03/2001
• Issued: 06/05/2007
• Est. Priority Date: 08/04/2000
• Status: Expired due to Term

• Current Assignee: Citrix Systems, Inc. (Cloud Software Group)
• Original Assignee: Avaya Technology Corporation Miami Lakes FLA US
• Inventors: Jaswa, Vijay, Chu, Albert Bonyao, Hong, Jack
• Primary Examiner(s): Flynn; Nathan J.
• Assistant Examiner(s): PATEL, ASHOKKUMAR B
• Application Number:
  US09/921,458
• Publication Number:
  US 20020048269A1
• Time in Patent Office: 2,132 Days
• Field of Search: 709/203, 709/226, 709/238, 711/120, 711/121, 711/122, 711/123, 711/119, 711/118, 711/154, 711/124, 711/144, 711/147, 711/163, 711/168, 370/389
• US Class Current: 709/226
• CPC Class Codes: H04L 2463/102 applying security measure for e-commerce data processing systems or methods, specially adapted for e-commerce G06Q30/00
• CPC Class Codes: H04L 45/566 Routing instructions carried by the data packet, e.g. active networks
• CPC Class Codes: H04L 61/30 Managing network names, e.g. use of aliases or nicknames name-to-address mapping H04L61/45
• CPC Class Codes: H04L 61/301 Name conversion
• CPC Class Codes: H04L 61/5014 using dynamic host configuration protocol [DHCP] or bootstrap protocol [BOOTP]
• CPC Class Codes: H04L 63/0428 wherein the data content is protected, e.g. by encrypting or encapsulating the payload
• CPC Class Codes: H04L 63/0464 using hop-by-hop encryption, i.e. wherein an intermediate entity decrypts the information and re-encrypts it before forwarding it
• CPC Class Codes: H04L 63/12 Applying verification of the received information cryptographic mechanisms or cryptographic arrangements for data integrity or data verification H04L9/32
• CPC Class Codes: H04L 63/166 at the transport layer
• CPC Class Codes: H04L 67/02 based on web technology, e.g. hypertext transfer protocol [HTTP]
• 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 67/1012 based on compliance of requirements or conditions with available server resources
• CPC Class Codes: H04L 67/1014 based on the content of a request
• CPC Class Codes: H04L 67/1017 based on a round robin mechanism
• CPC Class Codes: H04L 67/1023 based on a hash applied to IP addresses or costs
• CPC Class Codes: H04L 67/1027 Persistence of sessions during load balancing
• CPC Class Codes: H04L 67/288 Distributed intermediate devices, i.e. intermediate devices for interaction with other intermediate devices on the same level
• CPC Class Codes: H04L 67/2895 : Intermediate processing functionally located close to the data provider application, e.g. reverse proxies
• CPC Class Codes: H04L 67/34 : involving the movement of software or configuration parameters network booting or remote initial program loading [RIPL] G06F9/4416
• CPC Class Codes: H04L 67/561 : Adding application-functional data or data for application control, e.g. adding metadata
• CPC Class Codes: H04L 67/563 : Data redirection of data network streams
• CPC Class Codes: H04L 67/564 : Enhancement of application control based on intercepted application data
• CPC Class Codes: H04L 67/568 : Storing data temporarily at an intermediate stage, e.g. caching
• 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 67/63 : Routing a service request depending on the request content or context
• CPC Class Codes: H04L 69/329 : in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 : Network security protocols

Abstract

The present invention is directed to a network switch that determines when specific content is hot and directs flow to one or more cache servers. The architecture of the present invention can include a cache and a digest generator to store predetermined objects in the cache based on the digest generated by the digest generator.

Claims

1. An arrangement for serving information requests, comprising:

a plurality of information servers connected to a communications network, all of the information servers having a common address on the communications network and serving a set of information to clients, each of the information servers being configured to receive a transaction request associated with an individual transaction and to provide a response to each transaction request; and

a content director connecting the information servers to the communications network and distributing transaction requests among the information servers comprising;

a flow switch that selects an appropriate information server to service each transaction request and thereafter forwards at least portions of the transaction request to a selected one of the information servers;

a cache processor that accesses a cache;

the cache that stores, in a hot locator table identifying information frequently requested from the information servers and including, for each locator identifying corresponding information, a hit counter indicating a number of direct transaction requests, received by the plurality of servers over a determined time interval, requesting the corresponding information;

a digest generator that generates, when the hit counter for a locator indicates at least a threshold transaction request receipt frequency but not when the hit counter fails to indicate at least a threshold transaction receipt frequency, a digest value pointing to the location in the hot locator table where the corresponding entry is stored; and

a digest store that stores the digests corresponding to frequently requested content.

2. The arrangement of claim 1, wherein the flow switch parses plain text transaction requests to locate selected fields and wherein the content director further comprises:

a cryptographic module that decrypts, prior to parsing and information server selection by the flow switch, cipher text transaction requests and provides plain text transaction requests to the flow switch, wherein, prior to decryption, the cipher text transaction requests have not been routed by another flow switch.

3. The arrangement of claim 2, wherein, first and second encrypted transaction requests are received from different clients having a common electronic address and served substantially simultaneously by different information servers, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the flow switch to service transaction requests from the client, and wherein the flow switch uses at least one of an locator, a cookie, and a tag in the parsed plain text equivalent of each transaction request to select an appropriate information server to service each of the first and second transaction requests.

4. The arrangement of claim 1, wherein each in the hot table further has a corresponding timestamp indicating when the respective entry was last updated, and a tag identifying a corresponding information server providing the corresponding information.

5. The arrangement of claim 1, wherein the digest store includes a digest value for each frequently requested.

6. The arrangement of claim 5, wherein, when the hit counter for an indicates at least a threshold transaction request receipt frequency, the information corresponding to the locator is served by a cache information server and not an origin information server.

7. The arrangement of claim 6, wherein, when the hit counter for a locator falls below a threshold transaction request receipt frequency, the information corresponding to the locator is served by an origin information server and not a cache information server.

8. The arrangement of claim 1, wherein the digest value is determined according to the following equation:

L=h(K), where 0≦

L≦

M for all keys K, where K is at least a portion of the locator, h is the hash function, L is the location of K in the hot locator table, and M is the size of the hot locator table.

9. The arrangement of claim 1, further comprising:

at least one traffic manager located between the content director and one or more clients to effect load balancing across a plurality of content directors.

10. The arrangement of claim 1, wherein the content director includes a current connection table listing active connections between servers and clients, the current connection table comprising, for a selected locator, a session identifier identifying a session with a client, a persistency timestamp indicating when a last transaction request was received from the respective client for the selected locator, and cookie name and value.

11. The arrangement of claim 1, wherein the flow switch is operable to tag a transaction response, the tag identifying an information server generating the transaction response.

12. The arrangement of claim 11, wherein at least some of the responses include a cookie, wherein the cookie was previously generated by the information server previously assigned by the flow switch to service transaction requests from the client, and wherein the cookie is different from the tag.

13. The arrangement of claim 12, wherein the tag is concatenated to the cookie.

14. The arrangement of claim 13, wherein, during a first time interval, the flow switch is in a tagging mode in which the switch generates and appends tags to transaction responses and, during a second different time interval, the switch operates in a digesting mode in which digests are generated, locator hotness is monitored, and transaction requests are routed to information servers based on requested locator hotness and/or cookie, wherein, in the tagging mode, locator hotness is not monitored, and wherein, in the digesting mode, tags are not generated and appended to transaction responses.

15. In an arrangement comprising a plurality of information servers connected to a communications network, each of the information servers having a common address on the communication network, serving a set of information to clients, and being configured to receive a transaction request associated with an individual transaction and to provide a response to each transaction request, a method for serving transaction requests from clients comprising:

providing a content director connecting the information servers to the communications network and comprising at least one flow switch selecting an appropriate information server to service each transaction request and thereafter forward at least portions of the transaction request to a selected one of the information servers;

maintaining a hot locator table in a cache store of the content director, identifying information frequently requested from the information servers, the hot locator table including, for each locator identifying corresponding information, a hit counter indicating a number of direct transaction requests, received by the plurality of information servers over a determined time interval, requesting the corresponding information;

generating by a digest generator, when the hit counter for a selected locator indicates at least a threshold transaction request receipt frequency but not when the hit counter fails to indicate at least a threshold receipt frequency, a digest value pointing to the location in the hot table where the entry corresponding to the selected locator is stored; and

accessing a digest store comprising the digest values to select an information server to service a transaction request for frequently requested information.

16. The method of claim 15, further comprising:

a cryptographic module decrypting a cipher text transaction request to provide a plain text transaction request to a first flow switch;

the first flow switch parsing the plain text transaction request to locate one or more selected fields;

the first flow switch, based on the one or more selected fields, selecting an appropriate information server to service the transaction request; and

the first flow switch thereafter forwarding at least portions of the plain text transaction request to a selected one of the information servers, wherein the cipher text transaction request is decrypted prior to the parsing and selecting steps and wherein, prior to the decrypting step, the cipher text transaction request has not been directed to a flow switch other than the first flow switch.

17. The method of claim 16, further comprising:

receiving first and second encrypted transaction requests from different clients having a common electronic address, the requests being served substantially simultaneously by different information servers, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the first flow switch to service transaction requests from the client, and wherein the first flow switch uses at least one of an locator, a cookie, and a tag in the parsed plain text equivalent of each transaction request to select an appropriate information server to service each of the first and second transaction requests.

18. The method of claim 15, wherein each locator in the hot table further has a corresponding timestamp indicating when the respective entry was last updated, and a tag identifying a corresponding information server providing the corresponding information.

19. The method of claim 15, wherein a digest value is generated for each frequently requested.

20. The method of claim 19, further comprising:

when the hit counter for an indicates at least a threshold transaction request receipt frequency, directing a transaction request for information associated with the locator to a cache information server.

21. The method of claim 20, further comprising:

when the hit counter for an locator falls below a threshold transaction request receipt frequency, directing a transaction request for information associated with the locator to an origin information server.

22. The method of claim 15, wherein the digest value is determined according to the following equation:

L=h(K), where 0≦

L≦

M, for all keys K, where K is at least a portion of the locator, h is the hash function, L is the location of K in the hot locator table, and M is the size of the hot locator table.

23. The method of claim 15, wherein at least one traffic manager is located between the content director and one or more clients to effect load balancing across a plurality of content directors.

24. The method of claim 15, further comprising:

maintaining a current connection table listing active connections between servers and clients, the current connection table comprising, for a selected locator, a session identifier identifying a session with a client, a persistency timestamp indicating when a last transaction request was received from the respective client for the selected locator, and cookie name and value.

25. The method of claim 15, further comprising:

during a first time interval, the first flow switch tagging a transaction response, the tag identifying an information server generating the transaction response.

26. The method of claim 25, wherein at least some of the responses include a cookie, wherein the cookie was previously generated by the information server previously assigned by the first flow switch to service transaction requests from the client, wherein the tag is appended to the cookie, and wherein the cookie is different from the tag.

27. The method of claim 26, wherein the tag is concatenated to the cookie.

28. The method of claim 25, further comprising:

during a second different time interval, generating a digest value for frequently requested information, the digest value indicating a location where an object associated with the frequently requested information is stored;

monitoring the frequency of transaction requests for information; and

directing transaction requests to information servers based on the frequency of request of information and/or a cookie included in at least some of the transaction requests, wherein, in the first time interval, locator hotness is not monitored, and wherein, in the second time interval, tags are not generated and appended to transaction responses.

29. A computer readable medium comprising processor executable instructions to perform the steps of claim 15.

30. An arrangement for serving information requests, comprising:

a plurality of information servers connected to a communications network, all of the information servers having a common address on the communications network and serving a set of information to clients, each of the information servers being configured to receive a transaction request associated with an individual transaction and to provide a response to each transaction request; and

content director means for connecting the information servers to the communications network and distributing transaction requests among the information servers comprising;

first flow switching means for parsing plain text transaction requests to locate selected fields, selecting an appropriate information server to service each transaction request, and thereafter forwarding at least portions of the parsed transaction requests to a selected one of the information servers;

cache processing means for accessing a plurality of objects in response to communications received from the first flow switching means;

cache means for storing, in a hot locator table, the plurality of objects including locators identifying information frequently requested from the information servers and including, for each locator identifying corresponding information, a hit counter indicating a number of direct transaction requests, received by the plurality of information servers over a determined time interval, requesting the corresponding information;

digest generator means for generating, when the hit counter for a locator indicates at least a threshold transaction request receipt frequency but not when the hit counter fails to indicate at least a threshold transaction receipt frequency, a digest value pointing to the location in the hot locator table where the corresponding entry is stored; and

digest store means for storing the digests corresponding to frequently requested content.

31. The arrangement of claim 30, wherein the content director means further comprises:

decrypting means for decrypting, prior to parsing and information server selection by the first flow switching means, cipher text transaction requests and providing plain text transaction requests to the first flow switching means, wherein, prior to the decrypting function, the cipher text transaction request has not been directed to a flow switching means other than the first flow switching means.

32. The arrangement of claim 31, wherein, first and second encrypted transaction requests are received from different clients having a common electronic address and served substantially simultaneously by different information servers, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the first flow switching means to service transaction requests from the client, and wherein the first flow switching means uses at least one of an locator, a cookie, and a tag in the parsed plain text equivalent of each transaction request to select an appropriate information server to service each of the first and second transaction requests.

33. The arrangement of claim 30, wherein, when the hit counter for a locator indicates at least a threshold transaction request receipt frequency, the information corresponding to the locator is served by a cache information server and not an origin information server and wherein, when the hit counter for an locator falls below a threshold transaction request receipt frequency, the information corresponding to the locator is served by an origin information server and not a cache information server.

34. The arrangement of claim 30, wherein the digest value is determined according to the following equation:

L=h(K), where 0≦

L≦

M for all keys K, where K is at least a portion of the locator, h is the hash function, L is the location of K in the hot table, and M is the size of the hot table.

35. The arrangement of claim 30, wherein the first flow switching means tags a transaction response, the tag identifying an information server generating the transaction response, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the first flow switching means to service transaction requests from the client, wherein the cookie is different from the tag, and wherein the tag is concatenated to the cookie.

36. In an arrangement comprising a plurality of information servers connected to a communications network, the information servers having a common address on the communication network and serving a set of information to clients, each of the information servers being configured to receive a transaction request associated with an individual transaction and to provide a response to each transaction request, a method for serving transaction requests from clients comprising:

providing a flow switch in a content director for parsing plain text transaction requests to locate selected fields, select an appropriate information server to service each transaction request, and forward at least portions of the parsed transaction request to a selected one of the information servers;

maintaining a hot locator table in a cache store at the content director, identifying information frequently requested from the information servers, the hot locator table including, for each locator identifying corresponding information, a hit counter indicating a number of direct transaction requests, received by the plurality of servers over a determined time interval, requesting the corresponding information;

qenerating, when the hit counter for a selected locator indicates at least a threshold receipt frequency but not when the hit counter fails to indicate at least a threshold receipt frequency, a digest value pointing to a location in the hot locator table where the corresponding entry is stored;

when the hit counter for a locator indicates at least a threshold transaction request receipt frequency, locating the information associated with the locator at a cache information server and thereafter directing a transaction request for information associated with the locator to a cache information server; and

when the hit counter for a locator falls below a threshold transaction request receipt frequency, directing a transaction request for information associated with the locator to an origin information server.

37. The method of claim 36, further comprising:

a cryptographic module decrypting a cipher text transaction request to provide a plain text transaction request to a first flow switch;

the first flow switch parsing the plain text transaction request to locate one or more selected fields;

the first flow switch, based on the one or more selected fields, selecting an appropriate information server to service the transaction request; and

the first flow switch thereafter forwarding at least portions of the plain text transaction request to a selected one of the information servers, wherein the cipher text transaction request is decrypted prior to the parsing and selecting steps and wherein, prior to the decrypting step, the cipher text transaction request has not been directed to a flow switch other than the first flow switch.

38. The method of claim 37, further comprising:

receiving first and second encrypted transaction requests from different clients having a common electronic address, the requests being served substantially simultaneously by different information servers, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the first flow switch to service transaction requests from the client, and wherein the first flow switch uses at least one of an locator, a cookie, and a tag in the parsed plain text equivalent of each transaction request to select an appropriate information server to service each of the first and second transaction requests.

39. The method of claim 37, further comprising:

accessing tile hot locator table to select an information server to service a transaction request for frequently requested information.

40. The method of claim 39, wherein a digest value is generated for each frequently requested locator.

41. The method of claim 36, wherein each locator in the hot locator table further has a corresponding timestamp indicating when the respective entry was last updated, and a tag identifying a corresponding information server providing the corresponding information.

42. The method of claim 39, wherein the digest value is determined according to the following equation:

L=h(K), where 0≦

L≦

M for all keys K, where K is at least a portion of the locator, h is the hash function, 1, is the location of K in the hot locator table and M is the size of the hot locator table.

43. The method of claim 36, wherein at least one traffic manager is located between the content director and one or more clients to effect load balancing across a plurality of content directors.

44. The method of claim 36, further comprising:

maintaining a current connection table listing active connections between servers and clients, the current connection table comprising, for a selected locator, a session identifier identifying a session with the respective client, a persistency timestamp indicating when a last transaction request was received from a client for the selected locator, and cookie name and value.

45. The method of claim 36, further comprising:

during a first time interval, the first flow switch tagging a transaction response, the tag identifying an information server generating the transaction response.

46. The method of claim 45, wherein at least some of the responses include a cookie, wherein the cookie is generated by the information server previously assigned by the first flow switch to service transaction requests from the client, and wherein the cookie is different from the tag.

47. The method of claim 46, wherein the tag is concatenated to the cookie.

48. The method of claim 45, further comprising:

during a second different time interval, generating a digest value for frequently requested information, the digest value indicating a location where an object associated with the frequently requested information is stored;

monitoring the frequency of transaction requests for information; and

directing transaction requests to information servers based on the frequency of request of information and/or a cookie included in at least some of the transaction requests, wherein, in the first time interval, locator hotness is not monitored, and wherein, in the second time interval, tags are not generated and appended to transaction responses.

49. A computer readable medium comprising processor executable instructions to perform the steps of claim 36.