Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 148)

NOTE
Brocade VDX Data Center switches are shipped with factory-programmed world wide names (WWNs)
that are unique.
NOTE
In a logical chassis cluster, you can select the principal node by using the command line interface. For
more information, refer to
Selecting a principal node for the cluster on page 77.
RBridge ID allocation
RBridge ID assignment is implemented by leveraging proven Domain ID assignment protocols from
FC SANs. Request for Domain ID (RDI) and Domain ID Assignment (DIA) protocols ensure that a
single switch (the principal switch) centrally allocates the domain IDs for every RBridge in the fabric
and detects and resolves any domain ID collisions in the fabric. Brocade VCS Fabric supports up to 24
RBridge IDs.
Only the principal switch can allocate RBridge IDs (domain IDs) for all other switches in the fabric. The
principal switch starts the allocation process by allocating an RBridge ID for itself (using the ID value
supplied by the user), and initiates the DIA messages on all ports.
Other switches, which are now in subordinate mode, upon receiving the DIA frames respond with an
RDI message towards the principal switch. The process continues until all the switches in the fabric
have been allocated a unique ID.
Fabric routing protocol
After a RBridge ID is assigned to a switch, the Fabric Shortest Path First (FSPF) link state routing
protocol begins to form adjacencies and collects topology and inter-connectivity information with its
neighbors. Brocade VCS Fabric uses FSPF to calculate and elect a loop-free multicast tree rooted at
the multicast root RBridge. The multicast tree is calculated after the unicast routes are computed.
Configuring a Brocade VCS Fabric
Refer to the following tables for commands and examples used in configuring a Brocade VCS Fabric.
For command details, refer to the Network OS Command Reference.
The following lists command examples for enabling Brocade VCS logical chassis cluster mode:
Command examples for enabling logical chassis cluster mode TABLE 22
Command Command Behavior
switch# vcs logical-chassis enable
The VCS ID becomes the default
value of 1, the RBridge ID is not
changed, and Brocade VCS
logical chassis cluster mode is
enabled.
RBridge ID allocation
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