Method and system for LUN remapping in fibre channel networks
First Claim
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1. A Fibre Channel switch element in a Fibre Channel network, comprising:
- a port having (i) a receive segment for receiving a fibre channel frame;
(ii) a transmit segment for transmitting a fibre channel frame;
(iii) a control segment that stores an indicator value to identify whether an entire logical unit number (LUN) field in a FCP_CMND frame is to be replaced;
or an offset value is to be added or subtracted from the FCP_CMD frame; and
(iv) a hardware based LUN mapping cache that replaces the entire LUN field value in the FCP_CMND frame with the new LUN field value;
or adds the offset value to the FCP_CMND frame or subtracts the offset value from the FCP_CMND frame based on the indicator value, wherein for each replaced LUN field value in the FCP CMND frame;
a cyclic redundancy code (CRC) field value is replaced by a newly computed CRC value using the new LUN field value, and wherein the LUN Mapping cache generates the offset value that is either added to or subtracted from the LUN field value in the FCP CMND frame based on the indicator value.
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Abstract
A Fibre Channel switch element in a Fibre Channel network is provided. The Fibre Channel switch element includes a port that replaces a logical unit number (“LUN”) field value in a FCP_CMND frame. The port includes a LUN Mapping cache for replacing the LUN field value in a FCP_CMND frame. The LUN Mapping cache may also generate a value that is added to or subtracted from the LUN field value in the FCP_CMND frame. A control bit is used to activate LUN Mapping cache for mapping LUN values.
356 Citations
17 Claims
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1. A Fibre Channel switch element in a Fibre Channel network, comprising:
a port having (i) a receive segment for receiving a fibre channel frame;
(ii) a transmit segment for transmitting a fibre channel frame;
(iii) a control segment that stores an indicator value to identify whether an entire logical unit number (LUN) field in a FCP_CMND frame is to be replaced;
or an offset value is to be added or subtracted from the FCP_CMD frame; and
(iv) a hardware based LUN mapping cache that replaces the entire LUN field value in the FCP_CMND frame with the new LUN field value;
or adds the offset value to the FCP_CMND frame or subtracts the offset value from the FCP_CMND frame based on the indicator value, wherein for each replaced LUN field value in the FCP CMND frame;
a cyclic redundancy code (CRC) field value is replaced by a newly computed CRC value using the new LUN field value, and wherein the LUN Mapping cache generates the offset value that is either added to or subtracted from the LUN field value in the FCP CMND frame based on the indicator value.- View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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9. A storage area network (“
- SAN”
), comprising;a Fibre Channel switch element coupled to at least two network devices communicating with each other;
wherein the Fibre Channel switch element includes;
a port with (i) a receive segment for receiving a fibre channel frame;
(ii) a transmit segment for transmitting a fibre channel frame;
(iii) a control segment that stores an indicator value to identify whether an entire logical unit number (LUN) field in a FCP_CMND frame is to be replaced;
or an offset value is to be added or subtracted from the FCP_CMD frame; and
(iv) a hardware based LUN mapping cache that replaces the entire LUN field value in the FCP_CMND frame with the new LUN field value;
or adds the offset value to the FCP_CMND frame or subtracts the offset value from the FCP_CMND frame based on the indicator value, wherein for each replaced LUN field value in the FCP CMND frame;
a cyclic redundancy code (CRC) field value is replaced by a newly computed CRC value using the new LUN field value, and wherein the LUN Mapping cache generates the offset value that is either added to or subtracted from the LUN field value in the FCP CMND frame based on the indicator value. - View Dependent Claims (10, 11, 12, 13)
- SAN”
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14. A method for processing FCP_CMND frames in a storage area network having a fibre channel switch element, comprising:
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setting up a hardware based LUN mapping cache at a port of the fibre channel switch element, wherein the port includes a receive segment for receiving a fibre channel frame;
a transmit segment for transmitting a fibre channel frame; and
a control segment that stores an indicator value to identify whether an entire logical unit number (LUN) field in a FCP_CMND frame is to be replaced;
or an offset value is to be added or subtracted from the FCP_CMND frame; and
wherein the indicator value from the control segment activates the LUN mapping cache for mapping LUN values;comparing plural FCP_CMND frame fields with the LUN mapping cache entries; and
substituting a LUN field value in the FCP_CMND frame with a new LUN field value based on a LUN mapping cache entry;
wherein the LUN mapping cache replaces the entire LUN field value in the FCP_CMND frame with the new LUN field value;
adds the offset value to the FCP_CMND frame or subtracts the offset value from the FCP_CMND frame based on the indicator value, wherein for each replaced LUN field value in the FCP CMND frame;
a cyclic redundancy code (CRC) field value is replaced by a newly computed CRC value using the new LUN field value, and wherein the LUN Mapping cache generates the offset value that is either added to or subtracted from the LUN field value in the FCP CMND frame based on the indicator value. - View Dependent Claims (15, 16, 17)
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Specification