Configuring World Wide Names; Allocating Flat Fc Ids - Cisco DS-C9216I-K9 Configuration Manual

Chapter 31 Advanced Features and Concepts

Configuring World Wide Names

The world wide name (WWN) in the switch is equivalent to the Ethernet MAC address. As with the MAC
address, you must uniquely associate the WWN to a single device. The principal switch selection and
the allocation of domain IDs rely on the WWN. The WWN manager, a process-level manager residing
on the switch supervisor module, assigns WWNs to each switch. This WWN is independent of other
WWNs on each switch. This centralized control of WWN has the following advantages:
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•
Cisco MDS 9000 Family switches support three network address authority (NAA) address formats.
Table 31-1
NAA Address
IEEE 48-bit address
IEEE extended
IEEE registered
Caution Changes to the worldwide names should be made by an administrator or individual who is completely
familiar with switch operations.

Allocating Flat FC IDs

Fibre Channel standards require a unique FC ID to be allocated to a N port attached to a Fx port in any
switch. To conserve the number of FC IDs used, Cisco MDS 9000 Family switches use a special
allocation scheme.
Based on the assigned FC ID, some HBAs assume that no other ports have the same area bits and domain.
When a target is assigned with a FC ID that has the same area bits, but different port bits, the HBA fails
to discover these targets. To isolate these HBAs in a separate area, switches in the Cisco MDS 9000
Family follow a different FC ID allocation scheme. By default, the FC ID allocation mode is auto. In
the auto mode, only HBAs without interop issues are assigned FCIDs with specific ports bits. All other
HBAs are assigned FC IDs with a whole area (port bits set to 0).
The three options to allocate FCID are auto (default), none, and flat.
Changes to FC IDs should be made by an administrator or individual who is completely familiar with
Caution
switch operations.
OL-7753-01
Efficient sharing of WWN space
Centralized support across switches
Standardized NAA WWN Formats
NAA Type
Type 1 = 0001b
Type 2 = 0010b
Type 5 = 0101b
WWN Format
000 0000 0000b
Locally assigned
IEEE company ID: 24
bits
Cisco MDS 9000 Fabric Manager Switch Configuration Guide
Configuring World Wide Names
48-bit MAC address
48-bit MAC address
VSID: 36 bits
31-5