Switching method and switch device

• US 20030097454A1
• Filed: 11/01/2002
• Published: 05/22/2003
• Est. Priority Date: 11/02/2001
• Status: Active Grant

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Yamakawa, Satoshi, Ishikawa, Jun, Torii, Takashi
• Granted Patent: US 7,725,588 B2
• Time in Patent Office: Days
• US Class Current: 709/229
• CPC Class Codes: H04L 61/10 of different types
• CPC Class Codes: H04L 61/2596 Translation of addresses of the same type other than IP, e.g. translation from MAC to MAC addresses
• CPC Class Codes: H04L 61/457 containing identifiers of data entities on a computer, e.g. file names
• CPC Class Codes: H04L 67/1001 for accessing one among a plurality of replicated servers
• 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 67/1025 Dynamic adaptation of the criteria on which the server selection is based
• CPC Class Codes: H04L 67/1034 Reaction to server failures by a load balancer
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC

Abstract

A switch device has an object ID rewrite unit and a file access control unit. The object ID rewrite unit, when an original object ID is contained in a reply to be transferred, rewrites the original object ID to an information entraining object ID by inserting server identification information into the original object ID, while when the information entraining object ID is contained in a reply to be transferred, restores the information entraining object ID to the original object ID. The file access control unit includes a table for managing a combination of address information of a server and server identification information, estimating address information of a server corresponding to sever identification information contained in an information entraining object of a request to be transferred with reference to the table, and determines a destination of the request on the basis of the address information.

Claims

1. A switching method, at a switch device which is logically disposed between at least one client and at least one server for managing at least one object, for transferring a request on said object transmitted from said client to said server which manages said object, and for transferring a reply against said request from said server to said client which is a source of said request, said switching method comprising the steps of:

rewriting, when in the transferred reply an original object ID which is generated by the server is contained for identifying said object, the original object ID to an information entraining object ID by inserting server identifying information for identifying the server for managing an object corresponding to said original object ID from other servers;

restoring said information entraining object to said original object ID when said information entraining object ID is contained in the transferred request;

estimating address information of the server corresponding to said server identification information contained in the information entraining object ID of the transferred request with reference to a first table for managing a combination of said address information of said server and said server identification information; and

determining a destination of said request based upon said address information.

2. The switching method according to claim 1, wherein a common object unit identification information is contained in said server identification information for identifying a common object unit which is an unit for objects exported to public.

3. The switching method according to claim 1, comprising the steps of:

estimating address information corresponding to a transaction ID contained in the transferred reply with reference to a second table which associated said request and said reply and manages a combination of the transaction ID and address information of the client, said transaction ID being provided for discriminating said request and said reply between said client and said server; and

determining a destination of said reply on the basis of said address information is further provided.

4. The switching method according to claim 1, comprising the steps of:

estimating address information of a client to which the reply should be transferred with reference to a classification table which associates said request and said reply, and manages a combination of tag information of Layer 4 or lower of OSI model and address information of the client, said tag information being useable for uniquely specifying a combination of said client and said server; and

determining a destination of said reply based upon said address information.

5. The switching method according to claim 1, comprising the steps of:

estimating address information of the client to which the reply should be transferred with reference to a classification table which associates said request and said reply and manages a combination of a communication session port number with said server and address information of the client, said communication session port number being useable for uniquely specifying a combination between said client and said server; and

determining a destination of said reply on the basis of said address information.

6. The switching method according to claim 1, wherein a pseudo file system is employed for combining directory trees of objects exported to the public from the server and managing them as one integrated directory tree.

7. The switching method according to claim 6, further comprising the steps of:

referring to a second table for managing a combination of an object ID of an object corresponding to a joint of directory trees in respective common object units in said integrated directory tree and instruction information which is associated With said object ID and requires accesses to a plurality of destinations; and

executing a file system control processing of dividing, when a combination of the object ID and the instruction information both contained in a transferred request is entered into the second table, said request to requests transferred to said respective destinations, and assembling all the requests received from said respective destinations as a request transferred to said client.

8. The switching method according to claim 7, wherein the object ID registered in the second table is said information entraining object ID.

9. The switching method according to claim 6, further comprising the steps of:

referring to a second table for managing a combination of a movement source object ID, when an object exported to public by said server is moved, the just-mentioned object before the movement, a movement destination object ID of the foregoing object after the movement, and movement destination server identification information which is identification information of the movement destination server;

moving the foregoing object based upon a predetermined criteria with reference to the integrated directory tree managed by said pseudo file system, and entering in said second table a movement source object ID, a movement destination object ID and movement destination server identification information of said object; and

altering, when an object ID contained in a transferred request is coincident with the movement source object ID in the second table, said object ID to a movement destination object ID corresponding to said coincident movement source object ID, and further determining a destination server based upon movement destination server identification information corresponding to said movement source object ID.

10. The switching method according to claim 9, wherein said information entraining object ID is entered in said second table as the movement source object ID.

11. The switching method according to claim 9, further comprising the steps of:

referring to a second table for managing a combination with instruction information required for a specific operation in management of said integrated directory tree; and

transmitting, when a combination of an object ID and instruction information both contained in transferred request is entered into said second table, said request by making use of a communication session port represented by a port number X different from other requests, identifying a request received from said respective destinations from the other replies with an aid of said port number X, and further performing a specific processing for a return passage as a reply transmitted to said client.

12. The switching method according to claim 11, further comprising the steps of:

referring to a third table for managing a combination of an object ID of an object corresponding to a joint of directory trees in respective common object units in said integrated directory tree, and instruction information which is associated with said object ID and requires access to a plurality of destinations; and

when a combination of an object ID and instruction information both contained in a transferred request is entered into said third table, executing a file system control processing of dividing said request to requests transferred to said respective destinations, transmitting said divided requests using a port number corresponding to a communication session port different from other requests, and identifying all replies received from said respective destinations based upon said port numbers from other replies, and assembling all the replies as a reply transferred to said client.

13. The switching method according to claim 6, further comprising the steps of:

referring to a second table for managing a combination with instruction information required for a specific operation in management of said integrated directory tree; and

executing a file system control processing of adding, when a combination of an object ID and instruction information both contained in a request requiring the specific operation is entered in the second table, tag information capable of judgment in Layer 4 or lower of an OSI model to said request and transmitting the tag information, identifying a reply received from said respective destinations with an aid of said tag information, and executing a specific processing of a return path as a reply transferred to said client.

14. The switching method according to claim 6, further comprising the steps of:

referring to a second table for managing a combination of an object ID of an object corresponding to a joint of directory trees in respective common object units in said integrated directory tree, and instruction information which is associated with said object ID and requires access to a plurality of destinations; and

executing file system control processing for dividing, when a combination of an object ID and instruction information both contained-in a request to be transferred is contained in said second table, said request to requests to be transferred to said each destination, adding tag information capable of judgment in Layer 4 or lower of an OSI model to said divided request and transmitting the divided requests, and identifying all responses received from said each destination with an aid of said tag information, and further assembling said all responses as a reply to be transferred to said client.

15. The switching method according to claim 7, further comprising the steps of:

recording in an attribute of an object corresponding to a joint between directory trees in each common object unit in said integrated directory tree an attribute indicating that said object is a joint; and

joint processing judgment means of transmitting an instruction requiring an access to a plurality of destinations concerning said object without dividing said instruction and checking an attribute value of a reply corresponding to the instruction, and updating the processing to said step for executing file system control processing when there is an attribute value indicating that said object is said joint.

16. The switching method according to claim 7, further comprising the step of rewriting information in said second table such that when there is a movement request of the object including the joint of the directory tree in each common object unit in said integrated directory tree, actual movement of object at said joint and lower is not executed, and it forces the client to see that the object at the joint and lower are moved to a desired position.

17. The switching method according to claim 6, further comprising the steps of:

referring to a second table for managing a combination of an advancement state of movement processing of all moving objects upon processing where an object group which are exported to the public by said server are moved to another server, updating information required from the client in the processing of the movement, an movement source object ID of said object before the movement, a movement destination object ID of said object after the movement, and movement destination server identification information being identification information of a server at a movement destination;

referring to said pseudo file system, moving said object based upon a predetermined criteria, and entering in said second table the advancement state of the movement processing, updating log in a copying processing, the movement source ID of said object, the movement destination object ID, and the movement destination server identification information; and

altering a transfer destination of a method of transferring a request to the moved object from the client upon executing the movement processing on the basis of the advancement state registered in said second table and contents of said request, and hiding that the operation is in the movement processing.

18. The switching method according to claim 17, further comprising the step of altering information of an advancement state of the movement processing of said second table concerning a portion of objects of said group of the objects when copying of data to a movement destination is finished for the object group in said movement processing, and altering mapping information in said pseudo file system from the object of the movement source to the object of the movement destination.

19. The switching method according to claim 18, further comprising the step of judging whether or not a request is by an object ID associated with a movement source object with respect to an object for which the mapping is altered to a movement destination object to result in the movement being finished, and rewriting and transferring said movement source object ID to the movement destination object ID.

20. The switching method according to claim 17, wherein when a data write request is issued from the client to an object for which copying is finished during said movement processing, the write request is transferred to the movement source and the movement destination.

21. The switching method according to claim 17, wherein when a data write request is issued from the client to an object for which copying is being executed, the position of write data is registered as updating information in said second table, and thereafter the write request is transferred to the movement source, and after said copying processing is finished, data of updated portion is read out from the movement source and is written into an object of the movement destination.

22. The switching method according to claim 18, wherein when a data write request comes from the client to an object for which copying is being executed in said movement processing, updating data contained in the write request, and the position of the write data are registered as the updating information in said second table, and thereafter the write request is transferred to the movement source, and after said copying processing is finished, writing is executed into the object at the movement source.

23. A switching method, at a switch device which is logically disposed between at least one client and at least one server for managing at least one object, for transferring a request on said object transmitted from said client to said server which manages said object, and for transferring a reply against said request from said server to said client which is a source of said request, said switching method comprising the steps of:

estimating server identification information corresponding to an object ID contained in the request with reference to a first table for managing a combination of said object ID and server identification information for identifying a server for managing an object corresponding to said original object ID from other servers;

estimating address information of a server corresponding to said sever identification information with reference to a second table for managing a combination of address information of said server and said server identification information; and

determining a destination of said request based upon said address information.

24. The switching method according to claim 23, wherein when in said first table an object ID having the same data train as that of the object ID already entered is entered, a data train of the object ID is rewritten to another data train, and said rewritten data train is then entered in said first table.

25. The switching method according to claim 23, wherein a plurality of said tables each for managing said object ID are employed, corresponding to a protocol used and a version of the same.

26. A switch device disposed logically between at least one client and at least one server for managing at least one object, in which a request on said object transmitted from said client is transferred to said server for managing said object, and in which a reply to said request from said server is transferred to a client being the source of the transmission, said switch device comprising:

object ID rewrite means for rewriting, when an original object ID generated in said server for a purpose of identifying said object is contained in the request to be transferred, said original object ID to an information entraining object ID by inserting server identification information for identifying an object corresponding to said original object ID, and for restoring, when said information entraining object ID is contained in the request to be transferred, said information entraining object ID to said original object ID;

a first table for managing a combination of address information of said server and said server identification information; and

transfer means for estimating address information of a server corresponding to said server identification information contained in the information entraining object ID of the request to be transferred with reference to said first table, and determining a transfer destination based upon said address information.

27. The switch device according to claim 26, wherein common object unit identification information for identifying a common object unit being a unit where an object is exported to public is contained in said server identification information.

28. The switch device according to claim 26, further comprising:

a second table for associating said request and said reply, and managing a combination of a transaction ID provided for discriminating said request and said reply in said client and said sever and address information of the client; and

second transfer means for estimating address information corresponding to a transaction ID contained in the reply to be transferred with reference to said second table, and determining a destination of said reply based upon said address information.

29. The switch device according to claim 26, further comprising:

a classification table for associating said request and said reply, and managing a combination of tag information in an OSI model layer 4 or lower useable for uniquely specifying a combination of said client and said server and address information of the client; and

second transfer means for estimating address information of the client to which a reply should be transferred, and determining a destination of said reply based upon said address information.

30. The switch device according to claim 26, further comprising:

a classification table for associating said request and said reply, and managing a combination of a communication session/port number with a server useable for uniquely specifying a combination of said client and said server and address information of the client; and

second transfer means for estimating address information of the client to which a reply should be transferred with reference to said port number and said classification table, and determining a destination of said reply on the basis of said address information.

31. The switch device according to claim 26, wherein said object ID rewrite means comprises:

a second table for managing a combination of algorithm identification information for identifying an algorithm upon rewriting said original object ID to said information entraining object and restoring information for restoration of said original object ID;

reply processing means for rewriting said server identification information and said algorithm identification information to said information entraining object ID by inserting said server identification information and said algorithm identification information into said original object ID, and registering said algorithm identification information and said restoring information in said second table; and

request processing means for estimating restoring information corresponding to algorithm identification information contained in said information entraining object ID with reference to said second table, and restoring said information entraining object ID to said original object ID on the basis of said restoring information.

32. The switch device according to claim 31, wherein in said restoring information there are contained data deleted from said original object ID and a position of said data.

33. The switch device according to claim 32, wherein said reply processing means, when a data length of said original object ID is a fixed length, deletes part of said original object ID, and generates said information entraining object ID by inserting said algorithm identification information and said server identification information at a deleted position.

34. The switch device according to claim 32, wherein said reply processing means

generates, when a data length of said original object ID is a variable length, a total sum of said original object ID, said algorithm identification information, and said server identification information does not exceed a maximum data length, said information entraining object ID by adding said algorithm identification information and said server identification information to said original object ID;

and

deletes, when the total sum of the data lengths of said original object ID, said algorithm identification information, and said server identification information exceeds the maximum data length, part of said original object ID, and generates said information entraining object ID by inserting said algorithm identification information and said sever identification information to a deleted position.

35. The switch device according to claim 32, wherein insertion positions of said algorithm identification information and said server identification information in an information entraining object ID contained in all requests and replies are same.

36. The switch device according to claim 35, wherein data lengths of said algorithm identification information and said server identification information in an information entraining object ID contained in all requests and replies are same.

37. The switch device according to claim 26, further comprising a pseudo file system in which directory trees of an object exported to public from said server are combined for managing them as one integrated directory tree.

38. The switch device according to claim 37, further comprising:

a second table for managing a combination of an object ID of an object corresponding to a joint of directory trees in each common object unit in said integrated directory tree and instruction information which is associated with said object ID and requires an access to a plurality of destinations; and

file system control processing means for dividing, when a combination of an object ID and instruction information both contained in a request to be transferred is entered in said second table, said request to request transferred to said each destinations, and assembling all requests received from said each destination as a reply transferred to said client.

39. The switch device according to claim 38, wherein the object ID registered in said second table is said information entraining object ID.

40. The switch device according to claim 37, further comprising:

a second table for managing a combination of a movement source object ID, when an object exported to public by said server is subjected to movement, of said object before the movement, a movement destination object ID of said object after the movement, and movement destination server identification information being identification information for a server at a movement destination;

data movement processing means for moving said object based upon a predetermined criteria with reference to an integrated directory tree managed by said pseudo file system, and entering the movement source object ID, the movement destination object ID and the movement destination server identification information of said object in said second table; and

movement hiding means for altering, when an object ID contained in a request to be transferred is coincident with the movement source object ID in said second table, said object ID to a movement destination object ID corresponding to the coincident said movement source object ID, and determining a transmission destination server based upon movement destination server identification information corresponding to said movement source object ID.

41. The switch device according to claim 40, wherein in said second table said information entraining object ID is entered as the movement source object ID.

42. The switch device according to claim 40, wherein

said object ID rewrite means assembles a data movement flag indicative of a fact that data moves to the information entraining object ID, and sets, when an object ID contained in a request to be transferred is coincident with the movement source object ID in said second table, said data movement flag to be true;

said movement hiding means retrieves said second table only if said data movement flag is true.

43. The switch device according to claim 40, wherein in said second table a sub table is prepared for each generation number to which one generation is added for one time data movement;

said object ID rewrite means assembles, when an object ID contained in a request to be transferred is coincident with the movement source object ID, said generation number in said information entraining object ID; and

said movement hiding means retrieves only the sub table to which said generation number is added among respective sub tables in said second table.

44. The switch device according to claim 37, further comprising:

a second table for managing a combination with instruction information for which a specific operation is necessary in said integrated directory tree control; and

file system control processing means for transmitting, when the combination of an object ID and instruction information both contained in a request to be transferred is entered in said second table, said request using a transmission session port represented by a port number X different from other requests, identifying a reply received from said each destination from other replies, and executing a specific processing for a return passage as a reply transferred to said client.

45. The switch device according to claim 37, further comprising:

a second table for managing a combination of an object ID of an object corresponding to a joint between directory trees in each common object unit in said integrated directory tree, and instruction information which is associated with said object ID and requires an access to a plurality of destinations; and

file system control processing means for dividing, when the combination of the object ID and instruction information both contained in the request to be transferred is entered in said second table, said request to requests transferred to said respective destinations, transmitting said divided requests using a port-number corresponding to communication session ports different from other requests, identifying all replies received from said respective destinations with an aid of said port number from other replies, and assembling said received all replies as a reply to be transmitted to said client.

46. The switch device according to claim 37, further comprising:

a second table managing a combination with instruction information requiring specific operation in said integrated directory tree; and

file system control processing means for adding, when a combination of an object ID and instruction information both contained in a request requiring specific operation is entered in said second table, tag information capable of judgment in an OSI model layer 4 or lower to said request and transmitting it to respective destinations, identifying a reply received from said each destination with an aid of said tag information, and executing a specific processing for a return passage as a reply transmitted to said client.

47. The switch device according to claim 37, further comprising:

a second table for managing a combination of an object ID of an object corresponding to a joint between directory trees in each common object unit in said integrated directory tree and instruction information which is associated with said object ID and requires an access to a plurality of destinations; and

file system control processing means for dividing, when a combination of an object ID and instruction information both contained in a request to be transferred is entered in said second table, said request to a request transmitted to said each destination, adding tag information capable of judgment in an OSI model layer 4 and lower to said divided requests and transmitting them to said destinations, identifying all replies received from said respective destinations with an aid of said tag information, and assembling said all replies as a reply transferred to said client.

48. The switch device according to claim 38, further comprising:

pseudo file system control means for recording to attribute of an object corresponding to a joint between directory trees in each common object unit in said integrated directory tree, attribute indicative of a fact that said object is a joint; and

joint processing judgment means for transmitting an instruction associated with said object ID and requiring an access to a plurality of destinations without dividing said instruction, and checking an attribute of a reply thereof, and delivering, when there is an attribute indicative of said joint, the processing to said file system control processing means.

49. The switch device according to claim 35, further comprising a pseudo file system in which directory trees of an object exported to public from said server are combined and are managed as one integrated directory tree, wherein said pseudo file system comprises a merging agent for reading information of the integrated directory tree managed by other kinds of OS or protocols and reflecting it on the directory tree file system.

50. The switch device according to claim 38, further comprising high speed object movement means for rewriting information in the second table of the file system-control processing means for managing joints such that a client looks at, when there is a movement request for the object including joints of a directory tree in each common object unit in said integrated directory tree, the object as if the object at said joint or lower is moved to a desired position without executing actual movement of the object at said joint or lower.

51. The switch device according to claim 37, comprising:

a second table for managing a combination of an advancement status of a movement processing for moving all objects upon executing a processing in which a group of objects exported to public by said server to another server, update information required during the movement processing from the client, a movement source object ID of said object before the movement, a movement destination object ID of said object after the movement, and movement destination server identification information being identification information of a movement destination server;

movement processing control means for moving said object on the basis of a predetermined criteria with reference to said pseudo file system, and entering an advancement status of the movement processing, update log in a copying processing, a movement source ID of said object, a movement destination object ID, and movement destination server identification information into said second table; and

means for altering a transfer destination of a method of transferring a request to the moved object from the client upon executing the movement processing on the basis of the advancement state registered in said second table and contents of said request, and hiding that the operation is in the movement processing.

52. The switch device according to claim 51, comprising mapping information altering means for altering information of an advancement state of the movement processing of said second table concerning a portion of objects of said group of the objects when copying of data to a movement destination is finished for the object group in said movement processing, and altering mapping information in said pseudo file system from the object of the movement source to the object of the movement destination.

53. The switch device according to claim 52, further comprises object ID rewrite means for altering the mapping to the movement destination object by said mapping information alteration means, judging by said second table whether or not there is a request by an object ID associated with the movement source object for the object which movement is finished, and rewriting and transferring said movement source object ID to a movement destination object ID.

54. The switch device according to claim 51, wherein when write request for data from a client to an object where copying is finished during said movement processing, the write request is transferred to a movement source and to a movement destination, and synchronization is kept unchanged.

55. The switch device according to claim 51, wherein when a data write request comes from a client to an object in the copying processing during said movement processing, a position of the write data is registered in said second table as the update information, and thereafter the write request is transferred to the movement source, and after said copying processing is finished data of the updated portion is read from the movement source and is written in the movement destination object.

56. The switch device according to claim 51, wherein when a data write request comes from a client to an object in the copying processing during said movement processing, update data contained in the write request and a position of the write data are registered in the second table as the update information, and thereafter the write request is transferred to the movement source, and after said copying processing is finished, writing into a movement destination object is executed using said update information.

57. A switch device disposed logically between at least one client and at least one server for managing at least one object, in which a request on said object transmitted from said client is transferred to said server for managing said object, and in which a reply to said request from said server is transferred to a client being the source of the transmission, said switch device comprising:

a first table for managing a combination of said object ID and server identification information for identifying a server for managing an object corresponding to said original object ID from other servers;

a second table for managing a combination of address information of said server and said server identification information; and

transfer means for estimating server identification Information corresponding to an object ID contained in the request with reference to said table, and estimating address information of a server corresponding to said server identification information with reference to said second table, and determining a destination base upon said address information.

58. The switch device according to claim 57, wherein when in said first table an object ID having same data train as an already entered abject ID is entered, a data train of the object ID is rewritten to another data train, and the data train written in said first table is entered.

59. The switch device according to claim 57, wherein a plurality of the tables for managing said object ID are provided corresponding to used protocols and their versions.