Abstract:
The invention deploys a message-based data transport platform, in which a communication engine controls the delivery of server or other backup data or other large quantity data to a remote site based on message objects as fundamental units. Data sessions from one or more servers or other data sources may be buffered over established pipes for delivery to a remote data host which likewise contains messaging control. Relatively large message units may wait for communication over the channel in a queue, and be released when prior messaging is complete. Completion port or other polling or other mechanisms may indicate that connections have become open for use. In embodiments the message objects may be signed, or encrypted to safeguard against alteration or unauthorized viewing. The communication engine may rely upon TCP or other underlying transport mechanisms to effect lower level transmission.

Description:
PRIORITY 
       [0001]    This application is a divisional of U.S. patent application Ser. No. 10/608,191, Attorney Docket No. MS#303128.01/MFCP.103654, entitled “MESSAGE-BASED SCALABLE DATA TRANSPORT PROTOCOL,” filed 30 Jun. 2003, which is incorporated by reference herein. 
       CROSS-REFERENCE TO RELATED APPLICATION 
       [0002]    The subject matter of this application is related to the subject matter of U.S. patent application Ser. No. 10/608,192, Attorney Docket No. MS#303129.01/MFCP.103653, entitled “SYSTEM AND METHOD FOR MESSAGE-BASED SCALABLE DATA TRANSPORT,” having the same inventor as this application, assigned or under obligation of assignment to the same entity as this application, and which application is incorporated by reference herein. 
     
    
     FIELD OF THE INVENTION 
       [0003]    The invention relates to the field of information technology, and more particularly to a protocol designed to initiate and process large-scale network and other data backups or transfers via efficient message-based sessions. 
       BACKGROUND OF THE INVENTION 
       [0004]    The increased demand for data enterprise and other storage solutions has fueled corresponding demand in data backup and management tools. Companies, government and scientific organizations and others may require the reliable backup of gigabytes or terabytes of data, or more for archival and other purposes. While physical storage media such as storage area networks, optical storage media, redundant arrays of inexpensive disk (RAID) and other platforms have increased the total archival capacity available to data managers, the ability to efficiently harvest large data backups to host facilities has not always similarly progressed. 
         [0005]    For instance, a network administrator may periodically wish to extract the data updates stored to network storage, such as server drives on a local area network (LAN), and transport that data to a secure backup repository at a remote site. However, scheduling and executing that type of large-scale data transport is not always efficient using current technology. For instance, in the case of storing LAN data to a remote site, the administrator may attempt to move that quantity of data using a conventional network protocol, such as the Transfer Control Protocol (TCP). 
         [0006]    However, TCP as one transport solution may prove to be a difficult vehicle to communicate the data backup to the remote host, in part because TCP tends to decompose data into comparatively small packets, on the order of a few tens of bytes to a few thousands of bytes. When attempting to drive gigabytes of original or update data to a remote host, that scale will not suffice for efficient transport. Moreover, when performing data flow control on the channel, TCP may pause to seek available bandwidth or capacity on the channel as small as a few thousand bytes, stop and fill that available space in the pipe, and then wait for additional open slots. Again, pushing data on the order of megabytes, gigabytes or more through an intermittent channel at those scales is not efficient when using the granularity of TCP API. Better large-scale and other data backup technologies are desirable. Other problems exist. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention overcoming these and other problems in the art relates in one regard to a system and method for message-based scalable data transport, in which one or more individual servers or other nodes communicate data backups and other information to a remote storage host via a communication engine. In embodiments, the communication engine may interface to an underlying transport layer, such as TCP or other protocols, and mediate the data flow from the nodes to the remote store. The communication engine may decompose the data awaiting transport into a set of message objects which are buffered out over connections bundled into established data pipes. The encapsulation of the data into fundamental message objects permits more continuous delivery of the data payload, since the messaging continues as long as the connection is not occupied and is clear, in contrast for instance to pure TCP transport which may exhibit stop-and-go or “chatter” type behavior. In embodiments, one originating session may transmit data over more than one connection, to maximize channel utilization. The communication engine may perform traffic control based on the polling of completion ports to indicate message completion, or other channel mechanisms, but in general not requiring acknowledgment of individual packets or other comparatively smaller data objects. High throughput through the inventive platform and protocol may be achieved. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates an illustration of an overall network arrangement for processing data backups or other transfers, according to an embodiment of the invention. 
           [0009]      FIG. 2  illustrates an architecture for message-based data transfer, according to an embodiment of the invention. 
           [0010]      FIG. 3  illustrates a state diagram for message-based data transfer, according to an embodiment of the invention. 
           [0011]      FIG. 4  illustrates a flow diagram of message-based data transfer and associated protocol, according to an embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0012]      FIG. 1  illustrates an architecture in which a system and method for message-based scalable data transport may operate, according to an embodiment of the invention. As illustrated in that figure, in embodiments a set of data sources  102  may communicate with each other and with remote resources via network  104 . In embodiments, the set of data sources  102  may include, for instance, individual servers, clients or other nodes or assets having hard disk, magnetic tape, optical or other storage media. Network  104  may in embodiments be or include a local area network (LAN) such as an Ethernet network, a wide area network (WAN), or other network type or topology. Network  104  may in further embodiments be or include a dedicated network for purposes of data backup, a shared network utilized periodically to effect data transport, the Internet, or other networks or facilities. However, in general one or more of the data sources in the set of data sources  102  may have a requirement to backup data in whole or part, on a periodic or other basis and in comparatively large amounts. 
         [0013]    As illustrated, when data backups or other data transfers are generated, in embodiments the data transmitted by one or more of the data sources in the set of data sources  102  may be communicated to a storage server  106 , which in turn communicates the data to storage  108 . Storage  108  may in embodiments be or include hard disk resources such as RAID banks, optical media such as rewritable CD-ROMs or DVD-ROMs or others, magnetic tape drives, electronic storage capacity such as random access memory, flash memory or other electronic components, or other storage media. In embodiments, storage  108  may likewise be, include or interface to data storage resources such as storage area networks (SANs) or other assets. In embodiments, storage  108  may be equipped to accept and store relatively large-scale amounts of data backup, for instance megabytes, gigabytes, terabytes or more for enterprise and other purposes. 
         [0014]    As illustrated in  FIG. 2 , according to an embodiments of the invention each of the sources within the set of data sources  102  may communicate with communication engine  110  to initiate, manage and complete a data transport session to data server  106  or other remote or local destination. Communication engine  110  may include or interface to an application programming interface (API)  112  which may expose variables, calls and other interface parameters to the set of data sources  102  to carry out effective data transfer. In the embodiment as shown, each of the data sources in the set of data sources  102  may generate or be associated with a corresponding session within a set of sessions  114 . The set of sessions  104  may contain a queue of input/output buffers  116 , with one or more input/output buffer being allocated to each session. Other arrangements of sessions, queues, buffers and other resources are possible. An example of illustrative code which may in embodiments instantiate a new session from a session object class follows: 
         [0000]    
       
         
               
             
               
               
             
               
             
               
               
             
           
               
                 TABLE 1 
               
               
                   
               
             
             
               
                 CSession Object: 
               
             
          
           
               
                 typedef enum { 
                   
               
               
                   CE_SS_SEND_SYNC, 
                 // NEED to send sync 
               
               
                   CE_SS_APP_CONFIRM_ACCEPT_ACK, 
                 // NEED to send ACK from app 
               
               
                   CE_SS_APP_CLOSE_SESSION, 
                 // NEED to send FIN 
               
               
                   CE_SS_ACTION_REQUIRING_STATE, 
               
               
                   CE_SS_NULL, 
                 // null 
               
               
                   CE_SS_SENDING_SYNC, 
                 // Sending SYNC 
               
               
                   CE_SS_WAITING_ACK, 
                 // Waiting for ACK from machine Z 
               
               
                   CE_SS_WAITING_FOR_ACCEPT_ACK, 
                 // Waiting for ACK from app 
               
               
                   CE_SS_SENDING_APP_SESSION_ACK, 
                 // Sending ACK from machine Z to A 
               
               
                   CE_SS_SESSION_WAITING_FOR_SYNC_COMPLETE, 
                 // Waiting for WRITE complete 
               
               
                   
                  // after WRITE (SYNC) 
               
               
                   CE_SS_SENDING_FIN, 
                 // Sending FIN 
               
               
                   CE_SS_SESSION_CLOSED, 
                 // Session is CLOSED 
               
               
                   CE_SS_SESSION_READY, 
                 // Session is ready 
               
               
                 } CE_SESSION_STATE; 
               
             
          
           
               
                 Client Thread: 
               
             
          
           
               
                 CSession *pSes = new CSession; 
                   
               
               
                 hr=pSes-&gt;Init (L“175.1.1.10”, 
                 // IP address of backup LAN or just DNS name 
               
               
                     33701, 
                 // TCP port 
               
               
                     L“DLS_SERVER_1”, 
                 // principal&#39;s name 
               
               
                     2*1024*1024, 
                 // Output queue length 2MB 
               
               
                     4*1024*1024, 
                 // Input queue length 4 MB 
               
               
                     pSesContext, 
                  // points to “GUID_REPLICA” 
               
               
                     dwSesContextLen 
               
               
                     ); 
               
               
                 hr=pCE-&gt;CreateSession (pSes); 
                  // completes immediately, response on IOCP 
               
               
                   
               
             
          
         
       
     
         [0015]    Other code, languages or modules or different APIs are possible. 
         [0016]    As shown, each of the sessions in the set of sessions  114  may in turn communicate with a dispatcher module in the set of dispatcher modules  118 . The set of dispatcher modules  118  may themselves secure connections to one or more of a set of connections  120 . The set of connections  120  (which may be one or more) may in embodiments use multiple possible underlying communications mechanisms like TCP via Winsock, pipes or others. Each connection in the set of connections  120  aggregated into a logical pipe  122  may communicate with storage server  106 , or other remote or local hosts or resources. In embodiments pipe  122  may be established before establishing the set of connections  120  within that structure, but other setup phases and configurations are possible. In embodiments, the invention may support or employ a large number of connections in one or more pipes, for instance on the order of 1000 simultaneous connections, or more or less depending on implementation. 
         [0017]    As illustrated, the storage server  106  may contain a destination input/output queue  124 , to buffer incoming and outgoing message traffic to the storage server  106  or other ultimate destination. More particularly, at fixed, periodic, selected or other times, one or more of the sources in the set of data sources  102  may initiate a data transfer to the storage server  106  via communication engine  110  and associated resources. The data transfer may be or include, for instance, the backup of a server hard disk or other storage, the capture of large-scale scientific or commercial data, or other data transport tasks. Communication engine  110  may decompose the resident data from the one or more sources in the set of sources  102  into a set of message objects, for more efficient queuing and transfer. 
         [0018]    As shown, the session illustrated as Session A in the set of sessions  114  may generate two messages, labeled Message  1  and Message  2 , for transfer to storage server  106 . Those and other messages may in embodiments be on the order of many megabytes, or larger or smaller, in size. Likewise illustrated Session B has generated a message labeled Message  3  for transport to storage server  106 . Session C is illustrated as receiving a message labeled Message  4 , on the intake side. 
         [0019]    Dispatcher modules in the set of dispatcher modules  118  may bind multiple message streams from the set of input/output buffers  116  to one or more connections in the set of connections  120  and multiplex messages from different sessions into the same pipe of connections. As illustrated, dispatcher module labeled D 1  communicates traffic from Session A including Message  1  and Message  2  to Connection  1 , while dispatcher module D 2  combines the message stream to and from Session B and Session for connection to Connection  2 . Other combinations are possible. As shown, communication engine  110  interacting with the set of sessions  114  and the set of dispatchers  118  and other resources may attempt to drive the greatest possible number of pending messages through the set of connections  120  of pipe  122 , to achieve the greatest possible utilization of available bandwidth to storage server  106 . In embodiments, individual sessions in the set of session  114  may specify different types of network connections, such as ports, sockets or other parameters, for different messages or sets of messages. 
         [0020]    Each of the data sources in the set of data sources  102 , as well as individual connections in the set of connections  120  and other links in the transport chain to storage server  106 , may have different available bandwidths or other transmission characteristics. The queue of input/output buffers  116  in conjunction with the other transmission resources permit buffering action to accommodate the slowest link or links in that chain and varying characteristics of traffic both on sender and receiver side, while driving data transport to the greatest possible utilization. The communication engine  110  may for instance continuously or periodically scan the set of connections  120  to determine whether they are occupied with an outgoing or incoming message stream. 
         [0021]    In embodiments those probes or scans may be made using the completion port facility available under the Microsoft Windows™ family of operating systems, according to which the GetQueuedCompletionStatus and other commands may return messages indicating the departure of a given message from queue, or not. Since the communication engine  110 , set of dispatchers  118  and other resources may rely upon a message object as the fundamental unit of data transfer, the overall operation of the invention in embodiments may be directed toward fast large-scale transfers, since there is no stop and go effect from the processing of individual pieces of data as in pure TCP transmission modes. Rather, according to the invention a comparatively large-scale message may be generated, entered into queue in the queue of input/output buffers  116 , and released for transmission to storage server  106  or other destination. 
         [0022]    In embodiments, each session in the set of sessions  114  or communication engine  110  may wait to replenish the queue until the session itself determines that the transmission of the message object is complete. Since the duty to confirm that status resides on the transmitter side, there is no feedback loop from the receiver end, and that type of overhead cost is avoided. The set of sessions  114  may instead wait for confirmation from the queue of input/output buffers  116  that space in queue has opened, to prepare the next message for transmission. The set of sessions  114  thus may not attempt to refill the queue until whole message units are processed. The set of sessions  114  may incorporate a timeout function, to remove a message from the queue of input/output buffers  116  if the corresponding input/output buffer does not confirm the departure of the message to the set of connections  120  within a fixed amount of time, such as 1 minute. The set of sessions  114  may use other timeout or other checking criteria, such as variable delay times, a fixed or variable number of repeat attempts to be made before retiring a message, or others. 
         [0023]    Each of the message objects themselves may be communicated via the connections in the set of connections  120  using TCP itself as a lower level protocol. Other protocols are possible. Because the communication engine  110  and its associated message-based protocols govern flow control at a higher level, TCP datagrams may flow without small-scale flow control, error checking or other processing which would tend to slow down large, scalable transfers of the type managed by embodiments of the invention. 
         [0024]    In embodiments, the communication engine  110 , API  112  and other resources may introduce layers of security protection to protect the data transported to the storage server  106  or other destination. For instance, each session in the set of sessions  114  or connection in the set of connections  120  may be authenticated via digital certificates such as Kerberos, X.509 or other objects, secure socket layers or other mechanisms, before being permitted to be aggregated into pipe  122 . Individual messages themselves may likewise be encrypted to deter interception or alteration of the data being moved to storage server  106 . Various security, encryption or other techniques, such as Microsoft™ Security Support Provider Interface (SSPI), public key such as RSA standards, private keys such as Digital Encryption System (DES) mechanisms, or others may be employed to protect message content or other aspects of the transmission process. In embodiments, authentication, encryption and related information may be exposed at the level of API  112 . 
         [0025]      FIG. 3  illustrates a set of state machines  126  representing successive states of communications processing, according to an embodiment of the invention. As illustrated in that figure, the API  112  may present an interface to invoke communications resources to effect message-based data transport, such as server backup, large-scale data taking such as scientific or commercial data capture, or other purposes. Delivery of messages via the set of sessions  114  may in embodiments be reliable, in the sense of individual messages either being transmitted in whole, or queued for retransmission. As shown, multiple sessions may be established to multiple destinations, illustratively Session  1  connecting to Destination  1 , Session  2  connecting to Destination  1 , and Session  3  connecting to Destination  3 . As shown, Session  1  and Session  2  may loop between states  1  and  2 , awaiting completion of transmission of respective messages to Destination  1  or other triggering events. Communication with Destination  1  may be via a Connection  1  state machine for Session  1 , and Connection  2  state machine for Session  2 . Each of Connection  1  and Connection  2  may communicate with associated encryption and authentication state machines, to safeguard against unauthorized viewing or alteration of message objects. Each of Connection  1  and Connection  2  may likewise communicate with a respective Socket I/O State Machine which regulates access to respective Socket  1  and Socket  2  connections to Destination  1 . Session  3  may communicate with similar state machines processing transmission, encryption, authentication and socket connections to Destination  3 . In embodiments, transmission of individual messages may be asynchronous, in that messages may be queued and released according to channel occupancy and other factors, rather than according to timed slots. The creation of individual connections and sessions may likewise in embodiments be asynchronous. Additional state machines and interconnections are possible, and other states are possible for each state machine or process. 
         [0026]    Overall data transport processing is illustrated in  FIG. 4 . In step  402 , one or more sessions in the set of sessions  114  may be generated. In step  404 , a session sync message may be transmitted from a data source in the set of data sources  102  and transmitted to the destination input/output buffer  124  of storage server  106 . In step  406 , a completion message for session sync may be posted to storage server  106 . In step  408 , the storage server  106  may accept the session request. 
         [0027]    In step  410 , a session sync acknowledgement message may be transmitted from the destination input/output buffer  124  of storage server  106  to the corresponding input/output buffer in the set of input/output buffers  114  for the requesting data source. In step  412 , a completion message for session acknowledgement may be posted to the originating data source in the set of data sources  102 . In step  414 , the transmitting data source may transmit a first message, denoted Message  1 , to its associated input/output buffer in the set of input/output buffers  114 . In step  416 , the transmitting data source may transmit a second message, denoted Message  2 , to its associated input/output buffer in the set of input/output buffers  114 . In step  418 , the transmitting data source may transmit a third message, denoted Message  3 , to its associated input/output buffer in the set of input/output buffers  114 . In step  420 , the data source may receive an error message indicating that the corresponding input/output buffer is full, so that Message  3  is not accepted into queue. In step  422 , Message  1  may be transmitted to the destination input/output buffer  124  of storage server  106 . In step  424 , a completion message for the transmission of Message  1  may be posted to storage server  106  or other destination. In step  426 , an acknowledgement message acknowledging receipt of Message  1  may be transmitted to the input/output buffer of the data source of that message. In step  428 , a completion message for Message  1  may be transmitted to the corresponding data source. 
         [0028]    In step  430 , Message  2  may be transmitted to the destination input/output buffer  120  of storage server  106  or other destination. In step  432 , a completion message for Message  2  may be posted to the storage server  106 . In step  434 , Message  3  may be retransmitted to the input/output buffer corresponding to the data source of that message. In step  436 , an acknowledgment message indicating receipt of Message  2  with a window size (WndSize) of zero units may be transmitted to the input/output buffer of the data source for that message. In step  438 , a completion message for Message  2  may be posted to that source. In step  440 , Message  4  may be transmitted from a data source among the set of data sources  102  to its corresponding input/output buffer among the queue of input/output buffers  116 . 
         [0029]    In step  442 , the client application or other resource to receive Message  1  retrieves Message  1  from the destination input/output buffer  124 . In step  444 , an acknowledgement message for Message  2  with a window size (WndSize) of 1 unit may be transmitted to the corresponding input/output buffer of the source of that message. In step  446 , Message  3  may be transmitted to the destination input/output buffer  124  of storage server  106 . In step  448 , processing may terminate, repeat, or return to a prior processing point. 
         [0030]    The foregoing description of the invention is illustrative, and modifications in configuration and implementation will occur to persons skilled in the art. For instance, while the invention has in embodiments been described in terms of multiple data sources communicating via one communications link to a remote host, in embodiments one or more nodes or sessions may communicate via separate physical or logical links to a remote data host or other destination. 
         [0031]    Similarly, while the invention has in embodiments been described as transporting backup data to a single remote host, in embodiments the data may be delivered to separate logical or physical hosts or media. Other hardware, software or other resources described as singular may in embodiments be distributed, and similarly in embodiments resources described as distributed may be combined. The scope of the invention is accordingly intended to be limited only by the following claims.