Data communication coordination with sequence numbers

• US 20060271692A1
• Filed: 07/15/2005
• Published: 11/30/2006
• Est. Priority Date: 05/25/2005
• Status: Active Grant

• Current Assignee: Microsoft Technology Licensing LLC (Microsoft Corporation)
• Original Assignee: Microsoft Corporation
• Inventors: Raman, Balan Sethu, Kruse, David, Mohamed, Ahmed
• Granted Patent: US 8,316,129 B2
• Time in Patent Office: Days
• US Class Current: 709/229
• CPC Class Codes: G06F 16/182 Distributed file systems
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 63/123 received data contents, e.g. message integrity
• CPC Class Codes: H04L 67/01 Protocols
• CPC Class Codes: H04L 67/06 specially adapted for file transfer, e.g. file transfer protocol [FTP]
• CPC Class Codes: H04L 67/1097 for distributed storage of data in networks, e.g. transport arrangements for network file system [NFS], storage area networks [SAN] or network attached storage [NAS]
• CPC Class Codes: H04L 67/14 Session management for real-time applications in data packet communications networks H04L65/1066
• CPC Class Codes: H04L 67/147 Signalling methods or messages providing extensions to protocols defined by standardisation
• CPC Class Codes: H04L 69/02 Protocol performance
• CPC Class Codes: H04L 69/14 Multichannel or multilink protocols
• CPC Class Codes: H04L 69/18 Multiprotocol handlers, e.g. single devices capable of handling multiple protocols
• CPC Class Codes: H04L 69/24 Negotiation of communication capabilities
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: Y02D 30/50 in wire-line communication networks, e.g. low power modes or reduced link rate

Abstract

Described are sequence numbers for client-server communication, to control a client'"'"'s use of server resources. A server grants the client credits, and the client consumes a credit for sending each command to the server. Each credit corresponds to a sequence number, with the set of sequence numbers forming a valid command window. The server enforces that for each received command, the command includes a sequence number that is within the valid command window and that the sequence number has not been used with another command. The server may also maintain a maximum window size, such that clients with credits cannot send a command with a sequence number that beyond a maximum sequence number. When incorporated into a data communication protocol, quality of service, combating denial of service, detection of message loss, division of server resources, secure message signing, and other numerous benefits result.

Claims

1. In a network computing environment having a client and server, a method comprising:

granting the client at least one credit, each credit corresponding to a sequence number that the client can use for sending a command to the server, the set of one or more sequence numbers forming a valid command window; and

enforcing that for each received command, the command includes a sequence number that is within the valid command window and that the sequence number has not been used with another command.

2. The method of claim 1 further comprising, maintaining a maximum window size such that a client that has credits cannot send a command with a sequence number beyond a maximum sequence number corresponding to the maximum window size.

3. The method of claim 1 further comprising, in response to receiving a command, returning an unused sequence number to the client that adjusts the window.

4. The method of claim 3 wherein the unused sequence number is a monotonically increased value relative to a last number in the valid command window.

5. The method of claim 1 wherein each sequence number is a fixed size value 32 bits in length or greater.

6. The method of claim 1 further comprising, granting the client at least one blocking operation credit, and enforcing at the server that the client does not exceed a maximum number of blocking operation credits used.

7. The method of claim 6 further comprising, receiving a command corresponding to a blocking operation credit, returning data indicating that the blocking operation is in progress, along with an identifier for that operation that will be returned upon completion of the blocking operation.

8. The method of claim 7 further comprising, returning an unused sequence number to the client that adjusts the window in response to receiving the blocking operation command.

9. The method of claim 1 further comprising, receiving a request for an additional credit from the client, and denying the request to reduce the number of credits available to the client.

10. The method of claim 1 further comprising, revoking at least one credit previously granted to the client.

11. The method of claim 10 further comprising, informing the client that at least one credit will be revoked unless used prior to revoking.

12. At least one computer-readable medium having computer-executable instructions, which when executed perform steps, comprising:

granting a client a plurality of credits, each credit corresponding to a sequence number that the client uses for sending a command to a server, the sequence numbers forming a valid command window; and

upon receiving a command from the client;

verifying that the sequence number is within the window and has not been used before;

eliminating the corresponding sequence number from among those that the client can use and consuming one credit; and

determining whether to grant the client at least one other credit.

13. The computer-readable medium of claim 12 wherein the server determines to grant the client at least one other credit, and adjusts the valid command window with corresponding sequence numbers based on each credit granted.

14. The computer-readable medium of claim 12 wherein the server determines to not grant the client another credit thereby dynamically reducing the credits available to the client.

15. The computer-readable medium of claim 12 wherein the server determines to not grant the client another credit by evaluating a maximum window size.

16. The computer-readable medium of claim 12 having further computer executable instructions, comprising, revoking at least one credit previously granted to the client.

17. The computer-readable medium of claim 16 having further computer executable instructions, comprising informing the client that at least one credit will be revoked unless used prior to revoking.

18. In a network computing environment having a client and server, a server-side system comprising:

a mechanism for limiting use of server resources by controlling a number of credits granted to the client, the mechanism including;

a valid operation window, containing a unique number for each credit granted to the client;

an enforcement mechanism that ensures that to allow further server operations on a received command, the command includes a sequence number that is within the valid operation window and that the unique number has not been used with another command; and

an allocation mechanism that controls credits granted to the client and the unique numbers within the valid operation window.

19. The system of claim 18 wherein the mechanism for limiting use of server resources is associated with a server message block protocol driver.

20. The system of claim 18 wherein the mechanism includes means for revoking at least one credit previously granted to the client.