H3C Technologies H3C S12500-X Series Switches - Manual (Page 38)

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in the packet is higher, or the priority in the packet is the same and the WWN is smaller, the switch
replaces the locally-record principal switch information with the principal switch information
recorded in the packet, and notifies the other switches. Finally, all switches in the network make an
agreement on which switch is the principal switch.
3. When the PSST times out, if the locally-recorded principal switch information is the local switch, the
switch becomes the principal switch.
After the principal switch is selected, the WWN of the principal switch becomes the fabric name.
NOTE:
During the principal switch selection process, if a switch receives a packet that updates the principal switch
information, the switch must record the E_Port receiving the packet. The link relevant to this E_Port is called
the "upstream principal link."
Domain ID assignment
A domain represents a switch and all N_Ports connected to the switch. Each domain must have a domain
ID.
An FCF switch can automatically assign domain IDs. Alternatively, you can manually configure static
domain IDs.
• If you manually configure static domain IDs, you must assign a unique domain ID to each switch in
the fabric.
• If domain IDs are dynamically assigned, the fabric configuration process is performed to select a
principal switch and assign domain IDs. After the principal switch is selected, the principal switch
assigns domain IDs to all switches in the fabric. After the fabric configuration process, each switch
has a unique domain ID.
The dynamic domain ID assignment process is as follows:
1. The principal switch assigns a domain ID to itself. If the principal switch has been configured with
a desired domain ID, the principal switch assigns the domain ID to itself. Otherwise, the principal
switch assigns the smallest available domain ID to itself. After the principal switch assigns a
domain ID to itself, it notifies its downstream switches to request domain IDs from it.
2. After a downstream switch receives the notification, it starts to request a domain ID from the
principal switch. If the downstream switch is configured with a desired domain ID, it requests the
desired domain ID from the principal switch.
3. After the principal switch receives the domain ID request from the downstream switch, it assigns a
domain ID to it and notifies the downstream switch. The principal switch assigns domain IDs
following these rules:
{
If the downstream switch requests a desired domain ID that is available, the principal switch
assigns the domain ID to the downstream switch.
{
If the downstream switch does not request a desired domain ID or the desired domain ID is not
available, the principal switch assigns the smallest available domain ID to the downstream
switch.
{
If all available domain IDs have been assigned, the principal switch notifies the downstream
switch that no domain ID can be assigned to it.
4. After the downstream switch receives the domain ID assignment notification from the principal
switch, it works following these rules: