H3C Technologies H3C S10500 Series Switches - Manual (Page 86)

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Pairwise
Typically, servers do not need to access each other, and storage devices do not need to access each
other. Without the Pairwise feature, an access entry is generated for any pair of members in a zone.
The Pairwise feature allows a member to access only members with a different role in the same zone.
The following roles are defined for zone members:
• Initiator—Typically a server.
• Target—Typically a storage device.
When the Pairwise feature is enabled, access entries are not generated for initiator-initiator pairs or
target-target pairs, which saves hardware resources.
The Pairwise feature runs on a per-zone basis. A member can have different roles in different zones.
When the Pairwise feature is disabled for a zone, member roles do not take effect in that zone.
When a member acts as an initiator, it can access target members. When a member acts as a target, it
can access initiator members. When a member acts as both an initiator and a target, it can access both
target members and initiator members.
Zone distribution in basic zoning mode
Zone distribution occurs when a switch distributes its zone database to all the other devices in the same
fabric. The distributing switch is called a manager switch, and all other switches are called managed
switches.
In basic zoning mode, the following distribution types are provided:
• Complete distribution—Distributes both the active zone set and the zone database.
• Incomplete distribution—Distributes only the active zone set.
Zone distribution methods
You can distribute zones by using one of the following methods:
• Activate a zone set as the active zone set on a switch by using the zoneset activate command. At the
time of activation, the active zone set is distributed to all the other switches.
If the size of the zone set exceeds the system limit, the activation fails.
This method determines whether to carry the zone database according to the configured
distribution type.
• Distribute the active zone set and the zone database directly by using the zoneset distribute
command on a switch.
This method performs a complete distribution regardless of the configured distribution type.
Managed switches replace their respective active zone sets or zone databases with the received data,
regardless of the distribution types configured on them. If a managed switch receives only the zone
database, the managed switch does not retain its active zone set (if present) after replacement.
Zone distribution process
The manager switch completes data synchronization with each managed switch by using the following
packets:
• Acquire Change Authorization (ACA).
• Stage Fabric Configuration Update (SFC).