High performance memory based communications interface

• US 7,773,630 B2
• Filed: 09/26/2006
• Issued: 08/10/2010
• Est. Priority Date: 11/12/2005
• Status: Active Grant

• Current Assignee: III Holdings 1, LLC (Intellectual Ventures LLC)
• Original Assignee: Liquid Computing Corporation
• Inventors: Kemp, Michael F., Huang, Kaiyuan
• Primary Examiner(s): Yao; Kwang B
• Assistant Examiner(s): Rutkowski; Jeffrey M
• Application Number:
  US11/535,258
• Publication Number:
  US 20070223483A1
• Time in Patent Office: 1,414 Days
• Field of Search: None
• US Class Current: 370/474
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/245 using preemption
• CPC Class Codes: H04L 47/35 by embedding flow control information in regular packets, e.g. piggybacking
• CPC Class Codes: H04L 49/90 Buffering arrangements
• CPC Class Codes: H04L 49/9021 Plurality of buffers per packet
• CPC Class Codes: H04L 49/9042 Separate storage for different parts of the packet, e.g. header and payload
• CPC Class Codes: H04L 49/9094 Arrangements for simultaneous transmit and receive, e.g. simultaneous reading/writing from/to the storage element

Abstract

Embodiments of the present invention include enhanced functionalities and components within a Communication Endpoint Processor (CEP) that act as an interface between computational and communications domains. The embodiments disclosed herein deliver a complete memory mapped high performance interface that has the ability to support the simultaneous transmission of multiple frames of multiple sizes, and that has the ability to interrupt the transmission of lower priority frames in order to send higher priority frames.

Claims

1. A method for transmitting a data packet to a communications medium, the data packet including a header and a payload, the method comprising the steps of:

segmenting the data packet into one or more segments, each of the segments including a plurality of fragments stored in non-contiguous portions of a computer memory;

generating a segment descriptor for each segment, each segment descriptor including a fragment descriptor for each of the plurality of fragments in a respective segment such that one of the generated fragment descriptors is exclusively associated with the header and at least one other of the generated fragment descriptors is associated with at least a portion of the payload;

storing the generated fragment descriptors for each segment descriptor in contiguous portions of the computer memory;

sending the plurality of fragment descriptors for each segment descriptor across an interface;

retrieving the fragment descriptors from the interface;

reassembling each segment of the data packet by retrieving the header and the payload associated with the retrieved fragment descriptors for a respective segment descriptor from the computer memory, and

transmitting the reassembled data packet segments to the communications medium.

2. The method of claim 1, wherein the segmenting, generating, storing and sending steps are carried out by a communications endpoint processor (CEP) kernel.

3. The method of claim 1, wherein the segmenting, storing and sending steps are carried out in protected kernel space.

4. The method of claim 1, wherein the segmenting, storing and sending steps are carried out in user space.

5. The method of claim 2, wherein at least some of the functionality of the CEP kernel is carried out by software.

6. The method of claim 1, wherein the retrieving, reassembling and transmitting steps are carried out by a CEP engine.

7. The method of claim 6, wherein at least some of the functionality of the CEP engine is carried out by hardware.

8. The method of claim 1, wherein the segmenting step is carried out such that each fragment descriptor includes a data structure that defines a physical address in the computer memory of its corresponding fragment.

9. The method of claim 1, wherein the segmenting step is carried out such that each fragment descriptor includes a pointer to a physical address in the computer memory of its corresponding fragment, a length field indicating a length in bytes of its corresponding fragment, a flag field indicating whether its corresponding fragment is a last fragment of the payload, and an instance ID field.

10. The method of claim 9, wherein the segmenting step is carried out such that each fragment descriptor of each fragment into which the data packet is segmented stores a same instance ID in the instance ID field.

11. The method of claim 1, further comprising generating a segment descriptor that is associated with all of the fragment descriptors of the fragments into which the data packet is segmented.

12. The method of claim 1, wherein the data packet has a size greater than a predetermined maximum size and is segmented into a plurality of segments, and wherein at least one segment descriptor is stored in a portion of contiguous memory that is not contiguous to any portion of memory in which any other segment descriptor for the data packet is stored.

13. The method of claim 1, wherein the segmenting step segments the data packet into at least two segments whose size is equal to or less than a predetermined maximum size.

14. The method of claim 13, wherein each of the at least two segments is associated with a respective segment descriptor and wherein each of the at least two segments includes a same header and a plurality of fragments, the header and the plurality of fragments each being associated with a respective fragment descriptor.

15. The method of claim 14, wherein the segmenting step includes a chaining step to chain the respective segment descriptors associated with the at least two segments.

16. The method of claim 15, wherein chaining step includes generating a first segment chain descriptor that includes a start address field configured to store a start address of a first fragment descriptor of a first fragment of a first one of the at least two segments and at least one second segment chain descriptor between other ones of the at least two segments.

17. The method of claim 14, wherein each respective segment descriptor includes an instance ID field and wherein the segmenting step includes storing unique and sequentially numbered instance IDs in the respective instance ID fields.

18. A computer communications interface for transmitting a data packet to a communications medium, the data packet including a header and a payload, comprising:

a communications endpoint processor (CEP) interface;

a CEP kernel coupled to the CEP interface, the CEP kernel being configured to segment the data packet into one or more segments, each of the segments including a plurality of fragments stored in non-contiguous portions of a computer memory, to generate a segment descriptor for each segment, each segment descriptor including a fragment descriptor for each of the plurality of fragments in a respective segment such that one of the generated fragment descriptors is exclusively associated with the header and at least one other of the generated fragment descriptors is associated with at least a portion of the payload, to store the fragment descriptors for each segment descriptor in contiguous portions of the computer memory and to send the plurality of fragment descriptors for each segment descriptor across the CEP interface, and

a CEP engine coupled to the CEP interface, the CEP engine being configured to retrieve the fragment descriptors from the interface, to reassemble each segment of the data packet by retrieving the header and the payload associated with the fragment descriptors for a respective segment descriptor from the computer memory, and to transmit the reassembled data packet segments to the communications medium.

19. The computer communications interface of claim 18, wherein at least some of the functionality of the CEP kernel is implemented in software.

20. The computer communications interface of claim 18, wherein at least some of the functionality of the CEP engine is implemented in hardware.

21. The computer communications interface of claim 18, wherein each fragment descriptor includes a data structure that defines a physical address in the computer memory of its corresponding fragment.

22. The computer communications interface of claim 18, wherein each fragment descriptor includes a pointer to a physical address in the computer memory of its corresponding fragment, a length field indicating a length in bytes of its corresponding fragment, a flag field indicating whether its corresponding fragment is a last fragment of the payload and an instance ID field.

23. The computer communications interface of claim 22, wherein each fragment descriptor of each fragment into which the data packet is segmented stores a same instance ID in the instance ID field.

24. The computer communications interface of claim 18, wherein the CEP kernel is further configured to generate a segment descriptor that is associated with all of the fragment descriptors of the fragments into which the data packet is segmented.

25. The computer communications interface of claim 18, wherein the data packet exceeds a predetermined maximum size and is segmented into a plurality of segments, and wherein at least one segment descriptor is stored in a portion of contiguous memory that is not contiguous to any portion of memory in which any other segment descriptor for the data packet is stored.

26. The computer communications interface of claim 18, wherein the CEP kernel is further configured to segment a data packet whose size exceeds a predetermined maximum size such that the data packet is segmented into at least two segments whose size is equal to or less than the predetermined maximum size.

27. The computer communications interface of claim 26, wherein each of the at least two segments is associated with a respective segment descriptor and wherein each of the at least two segments includes a same header and a plurality of fragments, the header and the plurality of fragments each being associated with a respective fragment descriptor.

28. The computer communications interface of claim 27, wherein the CEP kernel is further configured to chain the respective segment descriptors associated with the at least two segments.

29. The computer communications interface of claim 28, wherein the CEP kernel is further configured to generate a first segment chain descriptor that includes a start address field configured to store a start address of a first fragment descriptor of a first fragment of a first one of the at least two segments and at least one second segment chain descriptor between other ones of the at least two segments.

30. The computer communications interface of claim 27, wherein each respective segment descriptor includes an instance ID field and wherein the segmenting step includes storing unique and sequentially numbered instance IDs in the respective instance ID fields.

31. The computer communications interface of claim 18, wherein the CEP kernel runs in protected kernel space.

32. The computer communications interface of claim 18, wherein the CEP kernel runs in user space.