A worldwide name is a unique name that is composed of 16 hexadecimal digits that are allocated to a node, service, or port on the SAN.
A worldwide name that is allocated to a node is called a worldwide node name (WWNN). A worldwide name that is allocated to a port or other SAN service is referred to as a worldwide port name (WWPN).
Each node canister in a control enclosure is allocated a WWNN. The WWNN is also used as the basis for the unique WWPN assigned to each Fibre Channel port or service on the node canister.
The WWNN for each node is stored within the enclosure. When you replace a node canister, the WWPN of the ports and services in the enclosure, do not change.
It is necessary to know the WWNNs and WWPNs when you configure the SAN. These names are also useful if you need to troubleshoot SAN and system connectivity issues.