System and method for sending and receiving frames between a public device and a private device

• US 6,401,128 B1
• Filed: 08/06/1999
• Issued: 06/04/2002
• Est. Priority Date: 08/07/1998
• Status: Expired due to Fees

• Current Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Original Assignee: Brocade Communications Systems, Inc. (Broadcom, Inc.)
• Inventors: Guan, Vincent W., Griffith, Eric, Wu, Ding Long, Stai, Jeffery, Banks, David C., Zhu, Jieming
• Primary Examiner(s): WILEY, DAVID ARMAND
• Application Number:
  US09/370,095
• Time in Patent Office: 1,033 Days
• Field of Search: 709/236, 709/301, 710/4, 712/1, 370/230, 370/349, 370/352, 370/351, 395/831
• US Class Current: 709/236
• CPC Class Codes: H04L 2101/645 Fibre channel identifiers
• CPC Class Codes: H04L 61/00 Network arrangements, protocols or services for addressing or naming
• CPC Class Codes: H04L 61/2596 Translation of addresses of the same type other than IP, e.g. translation from MAC to MAC addresses

Abstract

A system and method for sending frames between a public device and a private device comprise a phantom device mapping, an address translation, a frame payload translation, and a CRC regeneration. The system and method assign a phantom AL_PA for the public device and establishes a phantom device mapping between the phantom AL_PA and the public device'"'"'s Port_ID. With the phantom device mapping, the present invention directs all communication between the public device and the private loop device as if the communication were between a phantom device and the private device. Specifically, the system and method comprise a public-to-private address translation in one direction and a private-to-public address translation in the other direction. During the public-to-private address translation process, the source address of the frame is converted to a phantom AL_PA. The public-to-private address translation uses a Port_ID to phantom AL_PA mapping table and finds an entry where the Port_ID matches the source address. The public-to-private address translation replaces the source address of the frame with the phantom AL_PA of the matched entry, and the destination address with the AL_PA only of the destination device. The private-to-public address translation replaces the destination address of the frame with the Port_ID of the matched entry, and the source address with the fabric assigned address of the private device.

Claims

1. An apparatus disposed in a communication system including a fabric, at least one public device coupled to the fabric, and at least one loop device coupled to a loop, the apparatus comprising:

a frame receiving component for receiving a plurality of frames from the at least one public device to be sent to the at least one loop device and a plurality of frames from the at least one loop device to be sent to the at least one public device, each frame including a source address and a destination address; and

an address translation module, communicatively coupled to the frame receiving component, for (a) determining if the at least one loop device is a public or private device and if private, performing a public-to-private address translation on at least one of the plurality of frames received from the at least one public device and if public, forwarding the plurality of frames without address translation, and for (b) determining if the destination address provided by the at least one loop device is to a public or private device and if public, performing a private-to-public address translation on at least one of the plurality of frames received from the at least one private device and if private, forwarding the plurality of frames without address translation.

2. The apparatus of claim 1 wherein the address translation module assigns a phantom address to the plurality of frames received from the at least one public device.

3. The apparatus of claim 1 wherein the address translation module comprises a public-to-private address translation mapping having a plurality of fabric assigned addresses and a plurality of corresponding phantom addresses.

4. The apparatus of claim 1 wherein the address translation module converts the source address of the frame received from the at least one public device into a phantom address and the address translation module converts the destination address of the frame received from the at least one public device to a fabric-assigned private loop address.

5. The apparatus of claim 1 wherein the address translation module translates the phantom address of a frame received from the at least one loop device to an actual fabric-assigned address for the at least one public device.

6. The apparatus of claim 1 wherein the destination address o the frame received from the at least one loop device is converted from a phantom address to a fabric assigned address for the at least one public device, and the source address of the frame received from the at least one loop device is converted from a private loop address to a fabric-assigned address.

7. The apparatus of claim 1 wherein the address translation module converts a private loop address of the information frames from the at least one loop device to a fabric assigned address.

8. A method for transmitting a frame received from a public device to a loop device, the method comprising the steps of:

receiving a frame from the public device, the frame having a source address and a destination address;

determining if the destination address indicates a private loop device or a public loop device;

if the destination address indicates a private loop device, performing a public-to-private address translation on the frame received from the public device and transmitting the frame to the private loop device; and

if the destination address indicates a public loop device, transmitting the frame to the public loop device without performing an address translation.

9. The method of claim 8 wherein the public device has a Port_ID.

10. The method of claim 9 wherein the step of performing a public-to-private address translation on the frame received from the public device comprises the substep of:

assigning a phantom AL_PA to the public device for establishing a mapping between the phantom AL_PA and the Port_ID of the public device.

11. The method of claim 8 further comprising the steps:

prior to transmitting the frame to the private loop device converting the source address into a phantom address if the destination address indicates a private loop device.

12. An address translation module for use in a communication system for sending a plurality of frames across a fabric between at least one loop device coupled to a local loop and at least one public device coupled to the fabric, each frame having a source address and a destination address, the address translation module comprising:

a destination device determination for determining if the destination device is a public or private device;

a public-to-private address translation mapping for performing a public-to-private address translation on at least one of the plurality of frames received from the at least one public device if the destination device is a private device; and

a private-to-public address translation mapping for performing a private-to-public address translation on at least one of the plurality of frames received from the at least one loop device if the destination device is a public device.

13. The module of claim 12 wherein the public-to-private address translation mapping stores a plurality of fabric-assigned addresses and a plurality of corresponding phantom addresses.

14. The module of claim 12 wherein the public-to-private address translation mapping is used to convert the source address of at least one of the plurality of frames to a phantom address.

15. The module of claim 12 wherein the private-to-public address translation mapping is used to convert the source address of at least one of the plurality of frames to a fabric-assigned address.

16. A method for transmitting a frame received from a private loop device, the method comprising the steps of:

receiving a frame from the private loop device, the frame having a source address and a destination address;

determining if the destination address is to a public or private device;

performing a private-to-public address translation on the frame received from the private loop device if the destination address is to a public device; and

transmitting the frame to the public device.

17. The method of claim 16 wherein the public device has a Port_ID.

18. The method of claim 17 wherein the step of performing a private-to-public address translation on the frame received from the private loop device comprises the substeps of:

converting the source address from a private loop address to a fabric-assigned address for the private loop device; and

converting the destination address from a phantom address to a public address.