Dynamic multipath channel interface for input/output channels

• US 5,699,532 A
• Filed: 05/01/1996
• Issued: 12/16/1997
• Est. Priority Date: 06/01/1994
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Barrett, Linda, Stagg, Arthur James, Long, Lynn Douglas, Menditto, Louis Frank, Ward, Raymond Edward
• Primary Examiner(s): Amsbury, Wayne
• Assistant Examiner(s): ROBINSON, GRETA LEE
• Application Number:
  US08/641,593
• Time in Patent Office: 594 Days
• Field of Search: 395/200.12, 395/309, 395/821, 395/861, 395/200.01, 395/200.2, 364/931.45, 364/222.2, 375/260
• US Class Current: 710/305
• CPC Class Codes: G06F 13/122 where hardware performs an I/O function other than control of data transfer
• CPC Class Codes: G06F 13/385 for adaptation of a particular data processing system to different peripheral devices
• CPC Class Codes: H04L 1/1809 Selective-repeat protocols
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

A multi-path channel interface for computer input-output systems includes the ability to define and activate unbalanced groups of unidirectional communications sub-channels for a user application. Protocol independent exchange identifications permit not only unbalanced transmission groups but also allow user-controlled extensions for negotiating the values of transmission parameters at the time the transmission group is activated. When error correcting re-transmissions force the re-segmenting of data blocks, second level sub-segment indexing assure the proper order of delivery of the various segments and sub-segments. The exchange identifications include an identification of the user protocol being supported and thus permit interfacing with any user protocol.

Claims

1. An input and output communications subsystem for general purpose digital computer system comprising

at least one user application operating in said computer system according to a predetermined communications protocol to communicate blocks of data to a remote data utilization system over a communications channel capable of supporting multipath groups of sub-channels of limited transmission capacity;

means for dynamically allocating and activating each said group of sub-channels for transmission of said blocks of data in only one direction on each of said sub-channels prior to the transmission of said blocks of data, said means for dynamically allocating and activating said groups of sub-channels comprising;

means for transmitting one or more identification exchange messages between the two ends of said communications channel to negotiate agreed upon values of transmission parameters for said communications channel, said identification exchange messages including fields specifying the size and direction of transmission of each said sub-channel, the protocol of said user application, and a message extension field specifying the maximum capacity of a local data handling facility;

means responsive to the contents of said fields for activating a sub-channel having the specified size and direction;

means responsive to the contents of said extension field for segmenting data blocks from said user application into segments conforming to said maximum capacity, and

means for de-allocating any one said sub-channels when said one subchannel fails.

2. The input and output communications subsystem according to claim 1 further comprising,

means in said message for selectively identifying said predetermined communications protocol.

3. The input and output communications subsystem according to claim 1 further comprising,

means in said message for testing the security of said sub-channel.

4. A method for input and output communications in a general purpose digital computer system comprising

executing at least one user application in said computer system according to a predetermined communications protocol to communicate blocks of data to a remote data utilization system over a communications channel capable of supporting multipath groups of sub-channels of limited transmission capacity;

dynamically allocating and activating each said group of sub-channels for transmission of said blocks of data in only one direction on each of said sub-channels prior to the transmission of said blocks of data, side step of dynamically allocating and activating said groups of sub-channels comprising the steps of;

transmitting one or more identification exchange messages between the two ends of said communications channel to negotiate agreed upon values of transmission parameters for said communications channel, said identification exchange messages including fields specifying the size and direction of transmission of each said sub-channel, the protocol of said user application, and a message extension field specifying the maximum capacity of a local data handling facility;

in response to the contents of said fields, activating a sub-channel having the specified size and direction;

in response to the contents of said extension field, segmenting data blocks from said user application into segments conforming to said maximum capacity; and

de-allocating any one of said sub-channels when said one subchannel fails.

5. The method according to claim 4 further comprising the step of

selectively identifying said predetermined communications protocol in a portion of said message.

6. The method according to claim 4 further comprising the step of

utilizing one or more fields of said message for testing the security of said sub-channel.

7. In an input and output communications subsystem for general purpose computers, a remote data utilization system for communicating with said general purpose digital computer over said subsystem, said remote data utilization system comprising

means at said remote data utilization system for communicating blocks of date to said general purpose computer according to a predetermined protocol over a communication channel capable of supporting multipath groups of sub-channels of limited transmission capacity,

means at said remote data utilization system for dynamically allocating and activating each said group of sub-channels for transmission of said blocks of data in only one direction on each of said sub-channels prior to the transmission of said blocks of data, said means for dynamically allocating and activating said groups of sub-channels comprising

means at said remote utilization system for transmitting one or more identification exchange messages between the two ends of said communication channel to negotiate agreed upon values of transmission parameters for said communications channel, said identification exchange messages including fields specifying the size and direction of transmission of each of said sub-channels, the protocol of said remote data utilization system, and a message extension field specifying the maximum capacity of a local data handling facility,

means at said remote utilization system, responsive to the contents of said fields, for activating a sub-channel having the specified size and direction,

means at said remote utilization system, responsive to the contents of said extension field for segmenting data blocks into segments conforming to said maximum capacity, and

means at said remote data utilization system for de-allocating any one of said sub-channels when said one subchannel fails.

8. The remote data utilization system according to claim 7 further comprising

means in said message for selectively identifying said predetermined communications protocol.

9. The remote data utilization system according to claim 7 further comprising

means in said message for testing the security of said sub-channel.

10. In an input and output communications subsystem for general purpose computers, a method for communicating from a remote data utilization system comprising the steps of

communicating, from said remote data utilization system, blocks of date to said general purpose computer according to a predetermined protocol over a communication channel capable of supporting multipath groups of sub-channels of limited transmission capacity,

dynamically allocating and activating each said group of sub-channels for transmission of said blocks of data in only one direction on each of said sub-channels prior to the transmission of said blocks of data, said step of dynamically allocating and activating said groups of sub-channels comprising

transmitting one or more identification exchange messages between the two ends of said communication channel to negotiate agreed upon values of transmission parameters for said communications channel, said identification exchange messages including fields specifying the size and direction of transmission of each of said sub-channels, the protocol of said remote data utilization system, and a message extension field specifying the maximum capacity of a local data handling facility,

in response to the contents of said fields, activating a sub-channel having the specified size and direction,

in response to the contents of said extension field, segmenting data blocks into segments conforming to said maximum capacity, and

de-allocating any one said sub-channels when said one subchannel fails.

11. The method according to claim 10 further comprising

selectively identifying, in said message, said predetermined communications protocol.

12. The method according to claim 10 further comprising the step of

testing the security of said sub-channel.

13. A program storage device readable by a general purpose computer and embodying a program of instructions executable by said general purpose computer to perform a method for communicating from a remote data utilization system to said general purpose computer, said method comprising the steps of

communicating, from said remote data utilization system, blocks of date to said general purpose computer according to a predetermined protocol over a communication channel capable of supporting multipath groups of sub-channels of limited transmission capacity,

dynamically allocating and activating each said group of sub-channels for transmission of said blocks of data in only one direction on each of said sub-channels prior to the transmission of said blocks of data, said step of dynamically allocating and activating said groups of sub-channels comprising

transmitting one or more identification exchange messages between the two ends of said communication channel to negotiate agreed upon values of transmission parameters for said communications channel, said identification exchange messages including fields specifying the size and direction of transmission of each of said sub-channels, the protocol of said remote data utilization system, and a message extension field specifying the maximum capacity of a local data handling facility,

in response to the contents of said fields, activating a sub-channel having the specified size and direction,

in response to the contents of said extension field, segmenting data blocks into segments conforming to said maximum capacity, and

de-allocating any one said sub-channels when said one subchannel fails.

14. The program storage device according to claim 13 wherein said method further comprises the step of

selectively identifying, in said message, said predetermined communications protocol.

15. The program storage device according to claim 13 wherein said method further comprises the step of

testing the security of said sub-channel.

16. A multipath channel interface for either end of transmission media used for computer input/output operations, said multipath channel interface comprising

means, for each user facility using said transmission media, for defining a plurality of sub-channels in said transmission medium, a first subplurality of said subchannels extending in one direction on said media and a second subplurality of said subchannels extending in the other direction on said media,

means for dynamically allocating and activating one of said first and second subpluralities for the transmission of blocks of data in one direction on one of said subpluralities,

means for transmitting an identification exchange message on an allocated and activated subchannel, said message including the size and direction of transmission of each subchannel of said allocated and activated subchannels, the protocol of said user facility and the maximum capacity of said user facility,

means responsive to said message for allocating and activating one of said first and second subpluralities for the transmission of blocks of data in the other direction on the other of said subpluralities,

means responsive to said message for determining the ability of said user facility and said computer to conform to said maximum capacity,

means responsive to said message for disabling said first and second subpluralities when said user facility and said computer do not conform to said maximum capacity, and

means for substituting a replacement subchannel in either of said subpluralities in response to a failure in one of said subchannels.

17. The multipath channel interface according to claim 16 further comprising

means for transmitting at least one more identification exchange message on said transmission media for the purpose of negotiating the transmission parameters for each of said allotted and activated subchannels.

18. The multipath channel interface according to claim 16 further comprising

means for dividing data from said computer or from said user facility among the subchannels of said first or second subplurality, respectively.

19. A method for interfacing either end of transmission media used for computer input/output operations, said method for interfacing comprising the steps of

for each user facility using said transmission media, defining a plurality of subchannels in said transmission medium, a first subplurality of said subchannels extending in one direction on said media and a second subplurality of said subchannels extending in the other direction on said media,

dynamically allocating and activating one of said first and second subpluralities for the transmission of blocks of data in one direction on one of said subpluralities,

transmitting an identification exchange message on an allocated and activated subchannel, said message including the size and direction of transmission of each subchannel of said allocated and activated subchannels, the protocol of said user facility, and the maximum capacity of said user facility,

in response to said message for allocating and activating one of said first and second subpluralities, transmitting blocks of data in the other direction on the other of said subpluralities,

in response to said message, determining the ability of said user facility and said computer to conform to said maximum capacity,

in response to said message, disabling said first and second subpluralities when said user facility and said computer do not conform to said maximum capacity.

20. The method according to claim 19 further comprising the step of

transmitting at least one more identification exchange message on said transmission media for the purpose of negotiating the transmission parameters for each of said allotted and activated subchannels.

21. The method according to claim 19 further comprising the step of

substituting a replacement subchannel in either of said subpluralities in response to a failure in one of said subchannels.

22. The method according to claim 19 further comprising the step of

dividing data from said computer or from said user facility among the subchannels of said first or second subplurality, respectively.

23. A program storage device readable by a general purpose computer and embodying a program of instructions executable by said general purpose computer to perform a method for interfacing either end of transmission media used for computer input/output operations, said method comprising the steps of

for each user facility using said transmission media, defining a plurality of subchannels in said transmission medium, a first subplurality of said subchannels extending in one direction on said media and a second subplurality of said subchannels extending in the other direction on said media,

dynamically allocating and activating one of said first and second subpluralities for the transmission of blocks of data in one direction on one of said subpluralities,

transmitting an identification exchange message on an allocated and activated subchannel, said message including the size and direction of transmission of each subchannel of said allocated and activated subchannels, the protocol of said user facility, and the maximum capacity of said user facility,

in response to said message for allocating and activating one of said first and second subpluralities, transmitting blocks of data in the other direction on the other of said subpluralities,

in response to said message, determining the ability of said user facility and said computer to conform to said maximum capacity,

in response to said message, disabling said first and second subpluralities when said user facility and said computer do not conform to said maximum capacity.

24. The program storage device according to claim 23 wherein said method further comprises the step of

transmitting at least one more identification exchange message on said transmission media for the purpose of negotiating the transmission parameters for each of said allotted and activated subchannels.

25. The program storage device according to claim 23 wherein said method further comprises the step of

substituting a replacement subchannel in either of said subpluralities in response to a failure in one of said subchannels.

26. The program storage device according to claim 23 wherein said method further comprises the step of

dividing data from said computer or from said user facility among the subchannels of said first or second subplurality, respectively.

30. The interface means of claim 25 wherein the program storage device further comprises

means for transmitting over each subchannel of the group to the interface means at the other end of the channel system a second identification exchange message confirming the buffer size and protocol to be used in transmitting data blocks on the subchannel over which the second identification message is transmitted.

31. The interface means of claim 30 wherein each first identification exchange message further includes a random number field and the means for transmitting a second identification exchange message further comprises

means for examining the contents of the random number field of a first identification exchange message to determine if the remote data utilization system transmits the second identification exchange message.

32. The interface means of claim 31 wherein the means for examining the random number field of the first identification exchange message further comprises

means for comparing the contents of the random number field of the first identification exchange field to the value of a locally generated random number.

27. For use with an input and output channel subsystem between a computer and a utilization device, interface means at either end of the channel subsystem for communicating data blocks over the channel subsystem via subchannels of the channel subsystem, said interface means comprising

means for allocating a group of subchannels to an application, and

means for activating the group of subchannels prior to the transmission of said blocks of data, said means for activating comprising

means for transmitting first identification exchange messages over each said subchannel of the group to the other end of the channel subsystem, each first identification message including, for the subchannel over which it is transmitted, a direction field specifying the direction of transmission of the subchannel, a protocol field specifying the protocol to be used for data block transmission, and a buffer field specifying the maximum capacity of a buffer for communicating data blocks over the subchannel,

means responsive to the first identification exchange messages for activating each said subchannel having the specified buffer size, transmission direction and protocol, and

means for receiving said first identification exchange messages over each subchannel of the group from the other end of the subchannel system,

means for determining if prescribed fields of each of the received first identification exchange messages contain identical information, and

means for deallocating the group of subchannels if the corresponding identification exchange messages are not identical.

28. The interface means of claim 27 further comprising

means for receiving said first identification exchange messages over each subchannel of the group from the other end of the channel system,

means for examining each first identification exchange message to determine the ability to conform to the requirements of the protocol field, and

means for the deallocating said subchannels when the remote data utilization system is unable to conform to the requirements of the protocol field.

29. The interface means of claim 27 further comprising

means for examining the buffer field of each first identification exchange message to determine the ability to allocate a buffer of size specified in the first identification exchange message to the subchannel over which the first identification exchange message is received, and

means for transmitting a second exchange identification message to the interface means at the other end of the channel system specifying a buffer size that can be allocated to the associated sub-channel in the event that the buffer size in the first identification exchange message cannot be allocated.

33. For use with an input and output channel subsystem between a computer and a utilization device, an interfacing method to be used at either end of the channel subsystem for communicating data blocks over the channel subsystem via subchannels of the channel subsystem, said interfacing method comprising the steps of

allocating a group of subchannels to an application, and

activating the group of subchannels prior to the transmission of said blocks of data, said step of activating comprising the sub-steps of

transmitting first identification exchange messages over each said subchannel of the group to the other end of the channel subsystem, each first identification message including, for the subchannel over which it is transmitted, a direction field specifying the direction of transmission of the subchannel, a protocol field specifying the protocol to be used for data block transmission, and a buffer field specifying the maximum capacity of a buffer for communicating data blocks over the subchannel,

in response to the first identification exchange messages, activating each said subchannel having the specified buffer size, transmission direction and protocol, receiving said first identification exchange messages over each subchannel of the group from the other end of the subchannel system,

determining if prescribed fields of each of the received first identification exchange messages contain identical information, and

deallocating the group of subchannels if the corresponding identification exchange messages are not identical.

34. The interfacing method of claim 33 further comprising the steps of

receiving said first identification exchange messages over each subchannel of the group from the other end of the channel system,

examining each first identification exchange message to determine the ability to conform to the requirements of the protocol field, and

deallocating said subchannels when the remote data utilization system is unable to conform to the requirements of the protocol field.

35. The interfacing method of claim 33 further comprising the steps of

examining the buffer field of each first identification exchange message to determine the ability to allocate a buffer of size specified in the first identification exchange message to the subchannel over which the first identification exchange message is received, and

transmitting a second exchange identification message to the interface means at the other end of the channel system specifying a buffer size that can be allocated to the associated sub-channel in the event that the buffer size in the first identification exchange message cannot be allocated.

36. The interfacing method of claim 33 further comprising the steps of

at said remote data utilization system, transmitting over each subchannel of the group to the other end of the channel system a second identification exchange message confirming the buffer size and protocol to be used in transmitting data blocks on the subchannel over which the second identification message is transmitted.

37. The interfacing method of claim 36 further including the steps of

including in each first identification exchange message a random number field, and

the step of transmitting a second identification exchange message further comprises the step of

examining the contents of the random number field of a first identification exchange message to determine if the remote data utilization system transmits the second identification exchange message.

38. The interfacing method of claim 37 wherein the step of examining the random number field of the first identification exchange message further comprises the step of

comparing the contents of the random number field of the first identification exchange field to the value of a locally generated random number.

39. For use with an input and output channel subsystem between a computer and a utilization device, a program storage device readable by said computer and embodying a program executable by said computer to perform an interfacing method to be used at either end of the channel subsystem for communicating data blocks over the channel subsystem via subchannels of the channel subsystem, said interfacing method comprising the steps of

allocating a group of subchannels to an application, and

activating the group of subchannels prior to the transmission of said blocks of data, said step of activating comprising the sub-steps of

transmitting first identification exchange messages over each said subchannel of the group to the other end of the channel subsystem, each first identification message including, for the subchannel over which it is transmitted, a direction field specifying the direction of transmission of the subchannel, a protocol field specifying the protocol to be used for data block transmission, and a buffer field specifying the maximum capacity of a buffer for communicating data blocks over the subchannel, and

in response to the first identification exchange messages, activating each said subchannel having the specified buffer size, transmission direction and protocol.

40. The program storage device of claim 39 wherein said interfacing method further comprises the steps of

receiving said first identification exchange messages over each subchannel of the group from the other end of the channel system,

determining if prescribed fields of each of the received first identification exchange messages contain identical information, and

deallocating the group of subchannels if the corresponding ones of the prescribed fields in all of the received first identification exchange messages are not identical.

41. The program storage device of claim 39 wherein said interfacing method further comprises the steps of

receiving said first identification exchange messages over each subchannel of the group from the other end of the channel system,

examining each first identification exchange message to determine the ability to conform to the requirements of the protocol field, and

deallocating said subchannels when the remote data utilization system is unable to conform to the requirements of the protocol field.

42. The program storage device of claim 39 wherein said interfacing method further comprises the steps of

examining the buffer field of each first identification exchange message to determine the ability to allocate a buffer of size specified in the first identification exchange message to the subchannel over which the first identification exchange message is received, and

transmitting a second exchange identification message to the interface means at the other end of the channel system specifying a buffer size that can be allocated to the associated sub-channel in the event that the buffer size in the first identification exchange message cannot be allocated.

43. The program storage device of claim 39 wherein said interfacing method further comprises the steps of

at said remote data utilization system, transmitting over each subchannel of the group to the other end of the channel system a second identification exchange message confirming the buffer size and protocol to be used in transmitting data blocks on the subchannel over which the second identification message is transmitted.

44. The program storage device of claim 43 wherein said interfacing method further includes the steps of

including in each first identification exchange message a random number field, and

the step of transmitting a second identification exchange message further comprises the step of

examining the contents of the random number field of a first identification exchange message to determine if the remote data utilization system transmits the second identification exchange message.

45. The program storage device of claim 44 wherein the step of examining the random number field of the first identification exchange message in said interfacing method further comprises the step of

comparing the contents of the random number field of the first identification exchange field to the value of a locally generated random number.