Draft tutorial for IEEE company_id based FC-PH identifiers

Bob Snively bob.snively at Eng.Sun.COM
Wed Nov 27 13:09:59 PST 1996


* From the SCSI Reflector (scsi at symbios.com), posted by:
* bob.snively at Eng.Sun.COM (Bob Snively)
*

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Use of the IEEE Registration Authority assigned "company_id" with the 
ANSI X3.230 FC-PH Fibre Channel specification and its extensions

Bob Snively						Nov 27.1996

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Caution:

The IEEE administers the assignments of 24-bit company_id values.  The
assignments of these values are public, so that a user of an identifer 
defined by ANSI X3.230 can identify the manufacturer that provided the value.
The IEEE/RAC has no control over the assignments of the vendor-specified
fields and assumes no liability for assignments of duplicate identifiers.

A company shall use the same IEEE company_id
for all its IEEE Registration Authority based identifiers until the
identifier spaces using that company_id are substantially exhausted.

1.0  Introduction

The IEEE Registration Authority assigned "company_id" is the "IEEE
company identifier" defined in the Fibre Channel Standard, 
ANSI X3.230-1994.  Two formats are defined within FC-PH, while two
additional formats are defined in the proposal dated November 11, 1996
entitled Proposal for Fibre Channel world-wide name formats.

In the context of Fibre Channel, a set of unique word-wide identifiers 
is exchanged as part of the login process.  A unique identifier is
determined for each communicating node and for the port on each node
through which the login is performed.  Fibre Channel uses the NAA 
Name Address Authority) field to select among several alternative 
registration authorities and to identify the format of the world-wide
identifier.  The NAA field, defined and controlled by X3.230-1994,
occupies the high order 4 bits (bits 60-63) of the unique world-wide 
identifier, assuring that the identifier is unique even if the 60-bit
patterns derived using the registered IEEE company_id happen to be identical.
The complete 64-bit or 128-bit pattern, including the NAA bits, shall
be unique world wide.

The following FC-PH formats use the IEEE company identifer as the 
direct or indirect basis for their unique values. 

     NAA Bits     |   FC-PH format name         |  IEEE basis for
                  |                             |    format
   63  62  62  60 |                             |
  ________________|_____________________________|______________
                  |                             |
    0   0   0   1 |   IEEE                      | IEEE 803.2 48-bit identifier
    0   0   1   0 |   IEEE EXTENDED             | IEEE 803.2 48-bit identifier
    0   1   0   1 |   IEEE Registered Name      | IEEE company_id
    0   1   1   0 |   IEEE Registered Extended  | IEEE company_id


1.1   Glossary

Identified Company:  The company that has purchased and is identified by
	a particular value of the IEEE company_id.

2.0  Formats of FC-PH identifiers

The first two examples use the IEEE 802.3 48-bit identifier based on the
IEEE company_id value.  The second two examples use the IEEE
company_id value more directly.  

An example is provided for each format, showing how all fields are derived.

2.1  IEEE 48-bit identifier format 

This format is defined by ANSI X3.230-1994.

The FC-PH IEEE 48-bit world-wide identifier uses the 48-bit IEEE 802.1
universal LAN MAC address (ULA), which in turn is constructed from the
IEEE company_id.  This value is typically used to uniquely identify
a Fibre Channel node.  The format is shown in the following figure:

|   first byte    |                 |                 |                |
|63             56|55             48|47             40|39            32|
|________|________|________|________|_______|_________|________|_______|
| NAA =  |          Reserved        | ULA Byte 0| 0| 0|   ULA Byte 1   |
|        |                          |                 |                |
|  0001  |  0000  |  0000     0000  |11             04|03    00|35   32|
|________|________|_________________|_________________|________|_______|


|                 |                 |                 |    last byte   |
|31             24|23             16|15             08|07            00|
|________|________|________|________|________|________|________|_______|
|    ULA Byte 2   |    ULA Byte 3   |    ULA Byte 4   |   ULA Byte 5   |                                                       |                 |                 |                 |                |
|31             24|23             16|15             08|07            00|
|_________________|_________________|_________________|________________|


Bit 40 is the Individual/Group ID bit.  The bit shall be zero when
used with the FC-PH IEEE 48-bit address.

Bit 41 is the Universally Administered / Locally Administered Address
bit.  The bit shall be zero when used with the FC-PH IEEE 48-bit address.

ULA Bytes 0, 1, and 2 are generated using the IEEE company_id.  ULA Bytes
3, 4, and 5 represent a unique value provided by the identified company.

This format has been in common usage in X3.230 compliant Fibre Channel devices.

2.1.1  Example of IEEE 48-bit identifier format

In this example, the IEEE company_id value used is:

			AC DE 48

which has a binary representation of:

	    1010 1100   1101 1110   0100 1000

this value is combined with a value generated by the identified company 
of 00 00 80 to create a ULA of:

		  AC DE 48 00 00 80

The bit order is not changed for the Fibre Channel identifier as it
would be if transmitting a LAN address on a LAN link.

Using this ULA, the following 64-bit Fibre Channel IEEE 48-bit 
identifier format is created.

		10 00 AC DE   48 00 00 80

which would have a binary representation of:

         0001 0000   0000 0000   1010 1100   1101 1110 
         0100 1000   0000 0000   0000 0000   1000 0000

2.2	IEEE Extended identifier format

The IEEE extended identifier format allows the high order 12 bits that
are unused in the IEEE 48-bit format to be used as a
vendor specified field that extends the vendor specified
field contained in the ULA.  The identified company shall 
ensure that the combination of the 12-bit vendor specified field 
and the 3-byte vendor specified portion of the ULA  are unique 
company-wide.  Together with the NAA and IEEE company_id portion of the
ULA,  this guarantees that the  the overall FC-PH IEEE extended 
identifier shall be unique world wide.

Fibre Channel may use the vendor specified field to distinguish
different ports to a node.  The node may have an IEEE 48-bit FC-PH format
and each port may be distinguished by an IEEE Extended format that uses
the same ULA value as the node, but a unique vendor specified value for 
each port.

The vendor specified field may also be used by the identified company 
to extend the IEEE 48-bit ULA to a 60-bit field.  The identified company 
shall manage the fields such that every 64-bit value is unique world wide.

The format is shown in the following figure:

|   first byte    |                 |                 |                |
|63             56|55             48|47             40|39            32|
|________|________|________|________|_______|_________|________|_______|
| NAA =  |     Vendor Specified     | ULA Byte 0| 0| 0|   ULA Byte 1   |
|        |                          |                 |                |
|  0010  |        |        |        |11             04|03    00|35   32|
|________|________|________|________|_________________|________|_______|


|                 |                 |                 |    last byte   |
|31             24|23             16|15             08|07            00|
|________|________|________|________|________|________|________|_______|
|    ULA Byte 2   |    ULA Byte 3   |    ULA Byte 4   |   ULA Byte 5   |                                                       |                 |                 |                 |                |
|31             24|23             16|15             08|07            00|
|_________________|_________________|_________________|________________|


Bit 40 is the Individual/Group ID bit.  The bit shall be zero when
used with the FC-PH IEEE 48-bit address.

Bit 41 is the Universally Administered / Locally Administered Address
bit.  The bit shall be zero when used with the FC-PH IEEE 48-bit address.

This format has been in common usage in X3.230 compliant Fibre Channel devices.

2.2.1  Example of IEEE extended identifier format

In this example, the IEEE company_id value used is:

			AC DE 48

which has a binary representation of 

	    1010 1100 1101 1110 0100 1000

this value is combined with a value generated by the identified company 
of 00 00 80 to create a ULA of:

		  AC DE 48 00 00 80

The bit order is not changed for the Fibre Channel identifier as it
would be in transmitting a LAN address on a LAN link.

Using this ULA, the following 64-bit Fibre Channel IEEE extended identifier
can be created.  In this example, the vendor specified value selected
by the identified company is B17 hexadecimal, which has a binary 
representation of 1011 0001 0111.  The resulting Fibre Channel IEEE extended 
identifer is:

		2B 17 AC DE   48 00 00 80

which would have a binary representation of:

         0010 1011   0001 0111   1010 1100   1101 1110 
         0100 1000   0000 0000   0000 0000   1000 0000

2.3  IEEE Registered identifier format

The IEEE Registered identifier format provides a world-wide unique identifier 
typically used to identify any Fibre Channel object, including
ports, nodes, and fabrics.  This value is based directly on the
IEEE company_id, avoiding the requirement for the identified company
to maintain a 48-bit ULA registry. Instead, the identified company 
shall maintain a registry of vendor specified identifier values that
guarantees that all identifiers are unique world wide.  The registry
mechanism should guarantee that the identified company uses substantially
all of the identifiers that can be created with a single IEEE company_id 
before a new IEEE company_id is purchased and used. 

When the NAA value indicates that the format is IEEE registered, the 
identifier shall contain the 24-bit IEEE company_id 
followed by a 36-bit vendor specified identifier (VSID) which 
uniquely indicates a Node, an N_Port, an F_Port, a Fabric, or other  
object.

|   first byte    |                 |                 |                |
|63             56|55             48|47             40|39            32|
|________|________|________|________|________|________|________|_______|
| NAA =  |                IEEE company_id                      |  VSID |
|        |                                                     |
|  0101  |23    20|19             12|11             04|03    00|35   32|
|________|________|_________________|_________________|________|_______|


|                 |                 |                 |    last byte   |
|31             24|23             16|15             08|07            00|
|________|________|________|________|________|________|________|_______|
|                   Vendor Specified Identifier                        |
|                                                                      |
|31             24|23             16|15             08|07            00|
|_________________|_________________|_________________|________________|


2.3.1  Example of IEEE registered format

In this example, the IEEE company_id value used is:

			AC DE 48

which has a binary representation of 

	    1010 1100 1101 1110 0100 1000


In this example, the vendor specified value selected by the identified 
company is:

		 B 17 34 F6 2D

which has a binary representation of 

            1011  0001 0111  0011 0100  1111 0110  0010 1101
	  
The resulting IEEE registered format is:

		5A CD E4 8B 17 34 F6 2D

which would have a binary representation of:

         0101 1010   1100 1101   1110 0100   1000 1011 
         0001 0111   0011 0100   1111 0110   0010 1101

2.4    IEEE registered extended identifier format


The IEEE Registered Extended format provides a world-wide unique identifier 
typically used to identify any Fibre Channel objects that require
identifiers that are generated by the Fibre Channel node.  This value is 
based directly on the IEEE company_id, avoiding the requirement 
for the identified company to maintain a 48-bit ULA registry. Instead, the 
identified company shall maintain a registry of vendor specified identifier 
values that guarantees that all identifiers are unique world wide.

When NAA indicates that the format is IEEE registered extended, 
the identifier shall contain the 24-bit IEEE company_id , 
a 36-bit vendor specified identifier (VSID), and a 64-bit vendor specified
identifier extension which uniquely identifies the specified
object.  The identified company should use substantially
all of the identifiers that can be created with a single IEEE company_id 
and the VSID before a new IEEE company_id is purchased and used. The
vendor specified identifier extension may be used sparsely or assigned
by the identified object as long as uniqueness of the full 128-bit 
IEEE registered extended identifier is guaranteed.

The location of the vendor specified identifier extension is 
defined for each type of object.  At present, the only usage 
defined for this format is in the SCSI device identification page, 
where the IEEE registered extended format is recommended for uniquely 
identifying logical volumes in RAID systems and for similar uses.


|   first byte    |                 |                 |                |
|63             56|55             48|47             40|39            32|
|________|________|________|________|________|________|________|_______|
| NAA =  |                IEEE company_id                      |  VSID |
|        |                                                     |       |
|  0110  |23    20|19             12|11             04|03    00|35   32|
|________|________|_________________|_________________|________|_______|


|                 |                 |                 |                |
|31             24|23             16|15             08|07            00|
|________|________|________|________|________|________|________|_______|
|                                                                      |
|                   Vendor Specified Identifier                        |
|31             24|23             16|15             08|07            00|
|_________________|_________________|_________________|________________|

Vendor Specified Identifier Extension field

|                 |                 |                 |                |
|63             56|55             48|47             40|39            32|
|________|________|________|________|________|________|________|_______|
|                 Vendor Specified Identifier Extension                |
|                                                                      |
|63             56|55             48|47             40|39            32|
|_________________|_________________|_________________|________________|


|                 |                 |                 |    last byte   |
|31             24|23             16|15             08|07            00|
|________|________|________|________|________|________|________|_______|
|                                                                      |
|                 Vendor Specified Identifier Extension                |
|31             24|23             16|15             08|07            00|
|_________________|_________________|_________________|________________|


2.4.1  Example of IEEE registered extended format

In this example, the IEEE company_id value used is:

			AC DE 48

which has a binary representation of 

	    1010 1100 1101 1110 0100 1000


In this example, the vendor specified value selected by the identified
company is:

		 B 17 34 F6 2D

which has a binary representation of 

            1011  0001 0111  0011 0100  1111 0110  0010 1101

The vendor specified identifier extension, which may be selected by
the identified company or assigned uniquely by the object itself, has the
following value in this example:

		12 34 56 78 9A BC DE 31
	  
The resulting IEEE extended registered format is:

		6A CD E4 8B 17 34 F6 2D
                12 34 56 78 9A BC DE 31


which would have a binary representation of:

         0101 1010   1100 1101   1110 0100   1000 1011 
         0001 0111   0011 0100   1111 0110   0010 1101
         0001 0010   0011 0100   0101 0110   0111 1000
         1001 1010   1011 1100   1101 1110   0011 0001

3.0  Availability of references

Copies of the following documents can be obtained from ANSI: Approved ANSI 
standards, approved and draft international and regional standards (ISO, IEC, 
CEN/CENELEC, ITUT), and approved and draft foreign standards (including BSI, 
JIS, and DIN). For further information, contact ANSI Customer Service 
Department at 212-642-4900 (phone), 212-302-1286 (fax) or via the World Wide 
Web at http://www.ansi.org.

    ANSI X3.230-1995, Fibre Channel Physical and Signaling Interface (FC-PH)

Copies of these X3T10 draft documents are available for purchase from Global 
Engineering Documents. For further information, contact Global Engineering 
Documents at 800-854-7179 (phone) or 303-792-2181 (phone) or by mail at 15 
Inverness Way East, Englewood, CO 80122-5704.  The document is also available
on the SCSI web page at http://www.symbios.com/x3t10.

   Proposal for Fibre Channel world-wide name formats, R. Snively,
	November 27, 1996.


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