Methods and devices for transmitting data between storage area networks

• US 20040146054A1
• 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 7,738,493 B2
• Time in Patent Office: Days
• US Class Current: 370/395.52
• 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 69/329 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, a “slim” TCP stack is provided which eliminates the socket layer found in a conventional TCP stack, thereby eliminating socket buffers and the associated buffer-to-buffer copying. Moreover, by eliminating the socket layer, one eliminates the listen state. This condition allows TCP processing in an interrupt context instead of client/server operation with a listen state. Accordingly, some aspects of the invention provide for transmitting data between SANs in an interrupt context.

Claims

1. A TCP stack embodied in a machine-readable medium for controlling data transmitted between storage area networks, the TCP stack comprising:

an application layer for encapsulating outgoing frames from a first storage area network and de-encapsulating incoming frames from a second storage area network;

a TCP layer that receives outgoing frames directly from the application layer;

an IP layer that interacts with the TCP layer; and

a link layer that interacts with the IP layer, wherein the TCP stack does not include a socket layer.

2. The TCP stack of claim 1, wherein the application layer comprises an FCIP layer.

3. The TCP stack of claim 1, wherein the link layer comprises an Ethernet layer.

4. The TCP stack of claim 1, wherein the TCP stack performs processing in an interrupt context.

5. A method for controlling data transmitted between storage area networks, comprising:

receiving a first FCIP packet;

adding a TCP header to the first FCIP packet; and

transmitting the first FCIP packet to the Internet, wherein the receiving, adding and transmitting steps are all performed in an interrupt context.

6. The method of claim 5, wherein the interrupt context assigns a higher priority to command packets than to data packets.

7. The method of claim 5, further comprising:

receiving a second FCIP packet; and

determining whether the second FCIP packet may be sent in the interrupt context.

8. The method of claim 7, wherein it is determined that the second FCIP packet may be sent in the interrupt context, further comprising:

adding a TCP header to the second FCIP packet; and

transmitting the second FCIP packet to the Internet, wherein the adding and transmitting steps are performed in the interrupt context.

9. The method of claim 7, wherein the determining step comprises determining whether a maximum time has elapsed during the interrupt context.

10. The method of claim 7, wherein the determining step comprises determining whether a maximum number of FCIP packets has been sent prior to receiving an acknowledgement packet during the interrupt context.

11. The method of claim 7, wherein the determining step comprises determining whether a maximum number of bytes has been sent prior to receiving an acknowledgement packet during the interrupt context.

12. The method of claim 7, wherein the steps of receiving, adding and transmitting comprise a loop and wherein the determining step comprises determining whether a maximum number of loops has occurred during the interrupt context.

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

receiving a first FCIP packet;

adding a TCP header to the first FCIP packet; and

transmitting the first FCIP packet to the Internet, wherein the receiving, adding and transmitting steps are all performed in an interrupt context.

14. The computer program of claim 13, wherein the interrupt context assigns a higher priority to command packets than to data packets.

15. The computer program of claim 13, wherein the computer program further comprises instructions for controlling the network device to perform the following steps:

receiving a second FCIP packet; and

determining whether the second FCIP packet may be sent in the interrupt context.

16. The computer program of claim 15, wherein the network device determines that the second FCIP packet may be sent in the interrupt context and wherein the computer program further comprises instructions for controlling the network device to perform the following steps:

adding a TCP header to the second FCIP packet; and

transmitting the second FCIP packet to the Internet, wherein the adding and transmitting steps are performed in the interrupt context.

17. The computer program of claim 15, wherein the determining step comprises determining whether a maximum time has elapsed during the interrupt context.

18. The computer program of claim 15, wherein the determining step comprises determining whether a maximum number of FCIP packets has been sent prior to receiving an acknowledgement packet during the interrupt context.

19. The computer program of claim 15, wherein the determining step comprises determining whether a maximum number of bytes has been sent prior to receiving an acknowledgement packet during the interrupt context.

20. The computer program of claim 15, wherein the steps of receiving, adding and transmitting comprise a loop and wherein the determining step comprises determining whether a maximum number of loops has occurred during the interrupt context.

21. An apparatus for controlling data transmitted between storage area networks, the apparatus configured to perform the steps of:

receiving a first FCIP packet;

adding a TCP header to the first FCIP packet; and

transmitting the first FCIP packet to the Internet, wherein the receiving, adding and transmitting steps are all performed in an interrupt context.

22. The apparatus of claim 21, wherein the interrupt context assigns a higher priority to command packets than to data packets.

23. The apparatus of claim 21, wherein the apparatus is further configured to perform the steps of:

receiving a second FCIP packet; and

determining whether the second FCIP packet may be sent in the interrupt context.

24. The apparatus of claim 21, wherein the apparatus comprises a router.

25. The apparatus of claim 21, wherein the apparatus comprises a switch.

26. The apparatus of claim 21, wherein the apparatus comprises a fiber channel port adapter card.

27. The apparatus of claim 23, wherein it is determined that the second FCIP packet may be sent in the interrupt context, further comprising:

adding a TCP header to the second FCIP packet; and

transmitting the second FCIP packet to the Internet, wherein the adding and transmitting steps are performed in the interrupt context.

28. The apparatus of claim 23, wherein the determining step comprises determining whether a maximum time has elapsed during the interrupt context.

29. The apparatus of claim 23, wherein the determining step comprises determining whether a maximum number of FCIP packets has been sent prior to receiving an acknowledgement packet during the interrupt context.

30. The apparatus of claim 23, wherein the determining step comprises determining whether a maximum number of bytes has been sent prior to receiving an acknowledgement packet during the interrupt context.

31. The apparatus of claim 23, wherein the steps of receiving, adding and transmitting comprise a loop and wherein the determining step comprises determining whether a maximum number of loops has occurred during the interrupt context.