Users Guide

12
Using FlexAddress and FlexAdress Plus
Cards
This section provides information about FlexAddress and FlexAddress Plus cards, how to configure and
use these cards.
Related Links
About Flexaddress
About FlexAddress Plus
FlexAddress and FlexAddress Plus Comparison
About Flexaddress
If a server is replaced, the FlexAddress for the slot remains the same for the given server slot. If the server
is inserted in a new slot or chassis, the server-assigned WWN/MAC is used unless that chassis has the
FlexAddress feature enabled for the new slot. If you remove the server, it reverts to the server-assigned
address. You need not reconfigure deployment frameworks, DHCP servers, and routers for various fabrics
for identifying the new server.
Every server module is assigned unique WWN and/or MAC IDs as part of the manufacturing process.
Before FlexAddress, if you had to replace one server module with another, the WWN/MAC IDs changes
and Ethernet network management tools and SAN resources had to be reconfigured to identify the new
server module.
FlexAddress allows CMC to assign WWN/MAC IDs to a particular slot and override the factory IDs. Hence,
if the server module is replaced, the slot-based WWN/MAC IDs remain the same. This feature eliminates
the need to reconfigure Ethernet network management tools and SAN resources for a new server
module.
Additionally, the override action only occurs when a server module is inserted in a FlexAddress enabled
chassis; no permanent changes are made to the server module. If a server module is moved to a chassis
that does not support FlexAddress, the factory-assigned WWN/MAC IDs is used.
The FlexAddress feature card contains a range of MAC addresses. Before installing FlexAddress, you can
determine the range of MAC addresses contained on a FlexAddress feature card by inserting the SD card
into an USB Memory Card Reader and viewing the pwwn_mac.xml file. This clear text XML file on the SD
card contains an XML tag mac_start that is the first starting hex MAC address that is used for this unique
MAC address range. The mac_count tag is the total number of MAC addresses that the SD card allocates.
The total MAC range allocated can be determined by:
<mac_start> + 0xCF (208 - 1) = mac_end
where 208 is the mac_count and the formula is:
<mac_start> + <mac_count> - 1 = <mac_end>
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