200-150 · Question #192
Which two descriptions of fibre Channel WWNs are true? (Choose two.)
The correct answer is B. 64 or 128 bits long E. allocated to manufacturers by IEEE. Fibre Channel World Wide Names (WWNs) are 64-bit or 128-bit globally unique identifiers whose manufacturer prefixes are allocated by the IEEE, following a structure similar to Ethernet OUI assignments.
Question
Which two descriptions of fibre Channel WWNs are true? (Choose two.)
Options
- A48 bits long
- B64 or 128 bits long
- C96 bits long
- Dmanually configured on each device by an administrator
- Eallocated to manufacturers by IEEE
How the community answered
(36 responses)- A3% (1)
- B94% (34)
- D3% (1)
Why each option
Fibre Channel World Wide Names (WWNs) are 64-bit or 128-bit globally unique identifiers whose manufacturer prefixes are allocated by the IEEE, following a structure similar to Ethernet OUI assignments.
48 bits is the length of an Ethernet MAC address, not a Fibre Channel WWN; WWNs require at least 64 bits to provide sufficient address space for global uniqueness.
WWNs come in two sizes: the standard 64-bit WWN (8 bytes) and the extended 128-bit WWNx (16 bytes), both used to uniquely identify nodes and ports in a Fibre Channel fabric.
96 bits is not a defined or valid WWN length in the Fibre Channel specification; only 64-bit and 128-bit formats are standardized.
WWNs are factory-assigned by manufacturers using their IEEE-allocated OUI prefix and are burned into the device hardware, not manually configured by administrators.
The IEEE assigns Organizationally Unique Identifiers (OUIs) to Fibre Channel device manufacturers, which are embedded into WWNs to guarantee global uniqueness across all SAN environments, the same mechanism used for Ethernet MAC addresses.
Concept tested: Fibre Channel WWN structure and IEEE OUI allocation
Source: https://www.cisco.com/c/en/us/td/docs/storage/san_switches/mds9000/sw/rel_8_x/config/guide/b_Cisco_MDS_9000_NX-OS_FC_Alias_and_Zone_Configuration_Guide_8x/b_Cisco_MDS_9000_NX-OS_FC_Alias_and_Zone_Configuration_Guide_8x_chapter_011.html
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