System and method for TCP/IP offload independent of bandwidth delay product

• US 20040042464A1
• Filed: 08/29/2003
• Published: 03/04/2004
• Est. Priority Date: 08/30/2002
• Status: Active Grant

• Current Assignee: Avago Technologies General IP PTE Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Elzur, Uri, McDaniel, Scott S., Fan, Frankie, Lindsay, Steven B.
• Granted Patent: US 7,313,623 B2
• Time in Patent Office: Days
• US Class Current: 370/395.52
• CPC Class Codes: H04L 47/193 at the transport layer, e.g. TCP related
• CPC Class Codes: H04L 47/2441 relying on flow classification, e.g. using integrated services [IntServ]
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9063 Intermediate storage in different physical parts of a node or terminal
• CPC Class Codes: H04L 69/10 Streamlined, light-weight or high-speed protocols, e.g. express transfer protocol [XTP] or byte stream
• CPC Class Codes: H04L 69/12 Protocol engines
• CPC Class Codes: H04L 69/16 Implementation or adaptation of Internet protocol [IP], of transmission control protocol [TCP] or of user datagram protocol [UDP]
• CPC Class Codes: H04L 69/161 Implementation details of TCP/IP or UDP/IP stack architecture; Specification of modified or new header fields
• CPC Class Codes: H04L 69/162 involving adaptations of sockets based mechanisms secure socket layer H04L63/168
• CPC Class Codes: H04L 69/163 In-band adaptation of TCP data exchange; In-band control procedures
• CPC Class Codes: H04L 69/166 IP fragmentation; TCP segmentation

Abstract

Aspects of the invention may provide TCP offload, which may include acquiring TCP connection variables from a host and managing at least one TCP connection using the acquired TCP connection variables. At least a portion of the acquired TCP connection variables may be updated and at least some of the updated TCP connection variables may be transferred back to the host. In an aspect of the invention, the TCP connection variables may be variables that are independent of bandwidth delay product. At least a portion of the updated TCP connection variables may be utilized by the host to process the TCP connection or another TCP connection. The host may push the variables onto the stack and the TOE may pull the variables from the stack. Also, updated TCP connection variables may be pushed on the stack by the TOE and pulled from the stack by the host.

Claims

1. A system for providing TCP/IP offload, comprising:

a host; and

a TCP/IP offload engine (TOE) coupled to said host, wherein said host transfers control of at least a portion of TCP connection variables to said TOE and said TOE provides updated TCP variables back to said host.

2. The system according to claim 1, wherein said host transfers control of segment-variant TCP connection variables to said TOE and said TOE provides updated TCP segment-variant TCP connection variables back to said host.

3. The method according to claim 2, wherein said TCP segment-variant TCP connection variables further comprises:

IP packet identifier;

time remaining for retransmission;

time remaining for delay acknowledgement;

time remaining for keep alive;

congestion window variables comprising;

congestion window (SND_CWIN); and

slow start threshold (SSTHRESH);

round trip time variables comprising;

smoothed round trip time (RTT);

smoothed delta (DELTA); and

time remaining for PUSH; and

TCP state and timestamp send and receive sequence variables comprising;

sequence number for first un-ACK'"'"'d data (SND_UNA);

sequence number for next send (SND_NXT);

maximum sequence number ever sent (SND_MAX);

maximum send window (MAX_WIN);

sequence number for next receive (RCV_NXT); and

receive window size (RCV_WND).

4. The system according to claim 1,

wherein said host provides said TOE with a snapshot of at least one of connection-invariant TCP connection variables and segment-invariant TCP connection variables, said TOE transferring updated at least one of connection-invariant TCP connection variables and segment-invariant TCP connection variables back to said host;

and

wherein said TOE utilizes transferred segment-variant TCP connection variables and said snapshot of said at least one of said connection-invariant TCP connection variables and said segment-invariant TCP connection variables to process at least one of incoming and outgoing TCP segments.

5. The system according to claim 4, wherein said TOE utilizes said transferred segment-variant TCP connection variables and a snapshot of at least one of connection-invariant TCP connection variables and segment-invariant TCP connection variables to independently process incoming TCP segments.

6. The system according to claim 1, wherein said host provides said TOE with a snapshot of connection-invariant TCP connection variables and segment-invariant TCP connection variables.

7. The system according to claim 1, wherein said host provides said TOE with a snapshot of TCP connection variables that are not segment-variant TCP connection variables.

8. The system according to claim 1, wherein said host posts at least one buffer that is utilized by any TCP connection, a buffer that is dedicated to one or more TCP connections and an application buffer.

9. The system according to claim 1, wherein said TOE manages said TCP connection.

10. The system according to claim 1, wherein said TOE manages at least one of segmentation, acknowledgement processing, windowing and congestion avoidance.

11. The system according to claim 1, wherein said TOE maintains exclusive read-write access to offloaded segment-variant variables.

12. The system according to claim 1, wherein said TOE exclusively updates offloaded segment-variant variables.

13. The system according to claim 1, wherein said host maintains read-write access to segment-invariant variables.

14. The system according to claim 1, wherein said TOE has read-only access to segment-invariant variables.

15. The system according to claim 1, wherein:

said host sends a message to said TOE concerning a change in a particular TCP connection variable whose control was not transferred to said TOE, and

said TOE updates said particular TCP connection variable.

16. The system according to claim 1, wherein said TCP connection is an ESTABLISHED state.

17. The system according to claim 1, wherein said TCP connection variables are TCP connection variables that are independent of bandwidth delay product.

18. The system according to claim 1, wherein said host provides connection setups.

19. The system according to claim 18, wherein the system provides resistance to DoS attacks by allowing said host to handle said connection setups.

20. The system according to claim 1, wherein said host handles all TCP states exclusive of an ESTABLISHED state which may be offloaded to said TOE.

21. The system according to claim 1, wherein said TOE handles only connections that are in performance sensitive states.

22. The system according to claim 1, wherein said host processes resource utilization statistics in helping to determine which connections to offload and which connections to upload.

23. The system according to claim 1, wherein said host determines which connections to offload and which connections to upload.

24. The system according to claim 1, wherein at least one of said TOE and a device driver software for said TOE determines at least one of TCP connections to offload and TCP connections to upload.

25. A system for providing connection offload, comprising:

a host; and

a network interface card (NIC) coupled to said host, wherein, for a particular connection offloaded to said NIC, control of state information is split between said host and said NIC and said NIC uploads at least a portion of updated connection variables for said particular connection to said host.

26. The system according to claim 25, wherein said particular connection employs a connection-oriented transport layer protocol (TLP).

27. The system according to claim 26, wherein said connection-oriented TLP comprises a TCP.

28. The system according to claim 25, wherein said host transfers control of segment variant variables corresponding to said particular connection to said NIC.

29. A method for providing TCP/IP offload, comprising:

deciding to offload a particular TCP connection from a host to a TOE;

transferring control of connection variables of said particular TCP connection from said host to said TOE and transferring a snapshot of remaining connection variables whose control was not transferred to said TOE;

managing said particular TCP connection via said TOE using said at least a portion of said connection variables transferred to said TOE and at least a portion of said snapshot; and

updating at least a portion of said connection variables and a portion of said snapshot and transferring said updated at least said portion of said connection variables and said portion of said snapshot back to said host.

30. The method according to claim 29, wherein said one or more connection variables of said particular TCP connection transferred to said TOE comprise at least one segment-variant variables of said particular TCP connection.

31. The method according to claim 29, wherein said connection variables of said particular TCP connection transferred to said TOE lacks segment-invariant variables of said particular TCP connection.

32. The method according to claim 29, wherein said connection variables of said particular TCP connection transferred to the TOE lacks segment-invariant variables and connection-invariant variables of said particular TCP connection.

33. The method according to claim 29, further comprising:

determining if at least one of said connection variables controlled by said host have changed;

notifying said TOE of changes in said at least one connection variables controlled by said host that has changed; and

updating said connection variables in said TOE in accordance with said notified changes.

34. A method for providing TCP/IP offload, comprising:

deciding to offload an established TCP connection from a host to a TOE;

transferring control of segment-variant variables to said TOE from said host;

sending a snapshot of segment-invariant variables and connection-invariant variables to said TOE;

independently processing incoming TCP packets via said TOE based upon said segment-variant variables and said snapshot; and

updating at least a portion of said sent snapshot and at least a portion of said segment-variant variables and transferring at least a portion of said updated at least said portion of said sent snapshot and at least said portion of said updated segment-variant variables back to said host.

35. A method for processing a TCP connection, comprising:

establishing the TCP connection; and

sharing a control plane for said TCP connection between a host and a TOE; and

communicating updated TCP connection variables from said TOE back to said host.

36. The method according to claim 35, wherein said sharing of said control plane comprises transferring control of segment-variant variables corresponding to said TCP connection to said TOE.

37. The method according to claim 35, further comprising uploading said TCP connection to said host from said TOE.

38. The method according to claim 37, wherein uploading said TCP connection comprises transferring control of segment-variant variables corresponding to said TCP connection to said host.

39. The method according to claim 37, further comprising offloading said uploaded TCP connection to said TOE from said host.

40. The method according to claim 37, wherein offloading said uploaded TCP connection comprises transferring said control of said segment-variant variables corresponding to said uploaded TCP connection to said TOE.

41. A method for TCP offload, the method comprising:

acquiring TCP connection variables from a host;

managing at least one TCP connection using said acquired TCP connection variables;

updating at least a portion of said acquired TCP connection variables; and

transferring said updated at least a portion of said acquired TCP connection variables back to said host.

42. The method according to claim 41, wherein said TCP connection variables are independent of bandwidth delay product.

43. The method according to claim 41, further comprising utilizing at least a portion of said updated at least said portion of said acquired TCP connection variables to process said at least said at least one TCP connection by said host.

44. The method according to claim 41, further comprising pulling said TCP connection variables from a stack.

45. The method according to claim 41, further comprising pushing said updated at least a portion of said acquired TCP connection variables onto a stack.

46. A machine-readable storage, having stored thereon, a computer program having at least one code section for providing TCP offload, the at least one code section being executable by a machine for causing the machine to perform steps comprising:

acquiring TCP connection variables from a host;

managing at least one TCP connection using said acquired TCP connection variables;

updating at least a portion of said acquired TCP connection variables; and

transferring said updated at least a portion of said acquired TCP connection variables back to said host.

47. The machine-readable storage according to claim 46, wherein said TCP connection variables are independent of bandwidth delay product.

48. The machine-readable storage according to claim 46, further comprising code for utilizing at least a portion of said updated at least said portion of said acquired TCP connection variables to process said at least said at least one TCP connection by said host.

49. The machine-readable storage according to claim 46, further comprising code for pulling said TCP connection variables from a stack.

50. The machine-readable storage according to claim 46, further comprising code for pushing said updated at least a portion of said acquired TCP connection variables onto a stack.