Methods and devices for transmitting data between storage area networks

• US 20040146063A1
• Filed: 01/23/2003
• Published: 07/29/2004
• Est. Priority Date: 01/23/2003
• Status: Active Grant

• Current Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Original Assignee: Cisco Technology, Inc. (Cisco Systems, Inc.)
• Inventors: Golshan, Ali, Janakiraman, Venkatesh, Kolli, Madhuri, Mehta, Neelima, Krishnamoorthy, Pags, Ivaturi, Devi Prasad
• Granted Patent: US 7,957,409 B2
• Time in Patent Office: Days
• US Class Current: 370/428
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 12/4633 Interconnection of networks using encapsulation techniques, e.g. tunneling
• 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 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 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]
• CPC Class Codes: H04L 9/40 Network security protocols

Abstract

Methods and devices are provided for efficient transmission of data between storage area networks. According to some aspects of the invention, novel methods are provided for processing data packets sent by, or received from, a storage area network. Some such aspects of the invention involve storing a packet (or a portion of a packet) in a single memory location during an encapsulation or de-encapsulation process. Instead of repeatedly copying the packet during processing, pointer information is passed along that indicates the single memory location. In some aspects of the invention, the segment boundaries of a packet are retained after data transmission. If data in the packet need to be re-transmitted, the packet is re-transmitted with the same segment boundaries.

Claims

1. A method of transmitting data between storage area networks, comprising:

receiving a packet from a first storage area network;

storing the packet as a segment having segment boundaries in a memory location;

preparing the packet for transmission across an Internet Protocol network;

transmitting the packet across the Internet Protocol network; and

retaining the segment and the segment boundaries in the memory for a predetermined time after the transmitting step.

2. The method of claim 1, wherein the segment and the segment boundaries are retained in the memory location until an acknowledgement is received indicating reception of the packet.

3. The method of claim 1, further comprising:

re-transmitting the packet with the same segment boundaries if no acknowledgement is received indicating reception of the packet within a predetermined time.

4. The method of claim 1, wherein the storing step comprises reserving memory space within the memory location for a header, and wherein the preparing step comprises adding a first header in the reserved memory space.

5. The method of claim 1, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

6. The method of claim 4, wherein the following steps are performed if no acknowledgement is received indicating reception of the packet within a predetermined time:

adding a second header in the reserved memory space; and

re-transmitting the packet with the same segment boundaries and the second header.

7. A method of transmitting data between storage area networks, comprising:

receiving a packet from a first storage area network;

storing the packet as a segment in a first memory location;

preparing the packet for transmission across an Internet Protocol network without making copies of the packet in a second memory location; and

transmitting the packet across the Internet Protocol network.

8. The method of claim 7, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

9. The method of claim 7, wherein the preparing step comprises transmitting pointer information from a fiber channel driver to a Transmission Control Protocol module and wherein the pointer information indicates the first memory location.

10. The method of claim 9, wherein at least some of the pointer information is deleted after the transmitting step.

11. A method of transmitting data between fiber channel networks, comprising:

receiving a packet from a first fiber channel network, wherein the packet has been transmitted via an Internet Protocol network;

storing the packet as a segment in a first memory location;

preparing the packet for reception by a second fiber channel network without making copies of the packet in a second memory location; and

transmitting the packet to the second fiber channel network.

12. The method of claim 11, wherein the preparing step comprises transmitting pointer information from an Internet Protocol driver to a Transmission Control Protocol module, wherein the pointer information indicates the first memory location.

13. The method of claim 11, wherein the packet is encapsulated according to Transmission Control Protocol format and wherein the preparing step comprises de-encapsulating the packet.

14. A computer program embodied in a machine-readable medium for transmitting data between storage area networks, the computer program comprising instructions for controlling a network device to perform the following steps:

receiving a packet from a first storage area network;

storing the packet as a segment having segment boundaries in a memory location;

preparing the packet for transmission across an Internet Protocol network;

transmitting the packet across the Internet Protocol network; and

retaining the segment and the segment boundaries in the memory for a predetermined time after the transmitting step.

15. The computer program of claim 14, wherein the computer program controls the network device to retain the segment and the segment boundaries in the memory location until an acknowledgement is received indicating reception of the packet.

16. The computer program of claim 14, further comprising instructions for controlling the network device to re-transmit the packet with the same segment boundaries if no acknowledgement is received indicating reception of the packet within a predetermined time.

17. The computer program of claim 14, wherein the storing step comprises reserving memory space within the memory location for a header, and wherein the preparing step comprises adding a first header in the reserved memory space.

18. The computer program of claim 14, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

19. The method of claim 14, wherein the computer program controls the network device to perform the following steps if no acknowledgement is received indicating reception of the packet within a predetermined time:

adding a second header in the reserved memory space; and

re-transmitting the packet with the same segment boundaries and the second header.

20. A computer program embodied in a machine-readable medium for transmitting data between storage area networks, the computer program comprising instructions for controlling a network device to perform the following steps:

receiving a packet from a first storage area network;

storing the packet as a segment in a first memory location;

preparing the packet for transmission across an Internet Protocol network without making copies of the packet in a second memory location; and

transmitting the packet across the Internet Protocol network.

21. The computer program of claim 20, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

22. The computer program of claim 20, wherein the preparing step comprises transmitting pointer information from a fiber channel driver to a Transmission Control Protocol module and wherein the pointer information indicates the first memory location.

23. The computer program of claim 22, wherein at least some of the pointer information is deleted after the transmitting step.

24. A network device for transmitting data between storage area networks, the network device configured to perform the following steps:

receiving a packet from a first storage area network;

storing the packet as a segment having segment boundaries in a memory location;

preparing the packet for transmission across an Internet Protocol network;

transmitting the packet across the Internet Protocol network; and

retaining the segment and the segment boundaries in the memory for a predetermined time after the transmitting step.

25. The network device of claim 24, wherein the segment and the segment boundaries are retained in the memory location until an acknowledgement is received indicating reception of the packet.

26. The network device of claim 24, wherein the network device is configured to re-transmit the packet with the same segment boundaries if no acknowledgement is received indicating reception of the packet within a predetermined time.

27. The network device of claim 24, wherein the storing step comprises reserving memory space within the memory location for a header and wherein the preparing step comprises adding a first header in the reserved memory space.

28. The network device of claim 24, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

29. The network device of claim 28, wherein the network device is configured to perform the following steps if no acknowledgement is received indicating reception of the packet within a predetermined time:

adding a second header in the reserved memory space; and

re-transmitting the packet with the same segment boundaries and the second header.

30. A network device for transmitting data between storage area networks, wherein the network device is configured to perform the following steps:

receiving a packet from a first storage area network;

storing the packet as a segment in a first memory location;

preparing the packet for transmission across an Internet Protocol network without making copies of the packet in a second memory location; and

transmitting the packet across the Internet Protocol network.

31. The network device of claim 30, wherein the first storage area network is a fiber channel network, wherein the packet is received in fiber channel format and wherein the preparing step comprises encapsulating the packet according to Transmission Control Protocol.

32. The network device of claim 30, wherein the preparing step comprises transmitting pointer information from a fiber channel driver to a Transmission Control Protocol module and wherein the pointer information indicates the first memory location.

33. The network device of claim 32, wherein at least some of the pointer information is deleted after the transmitting step.

34. An apparatus for transmitting data between storage area networks, comprising:

means for receiving a packet from a first storage area network;

means for storing the packet as a segment having segment boundaries in a memory location;

means for preparing the packet for transmission across an Internet Protocol network;

means for transmitting the packet across the Internet Protocol network; and

means for retaining the segment and the segment boundaries in the memory for a predetermined time after the transmitting step.

35. The apparatus of claim 34, wherein the segment and the segment boundaries are retained in the memory location until an acknowledgement is received indicating reception of the packet.

36. The apparatus of claim 34, further comprising:

means for re-transmitting the packet with the same segment boundaries if no acknowledgement is received indicating reception of the packet within a predetermined time.