Network OS Administration Guide

Supporting Network OS 6.0.1a

Part Number: 53-1003768-04

Brocade VCS Fabric formation

Brocade VCS Fabric technology uses RBridge identifiers (IDs) to discover fabric creation problems, such as duplicate IDs. The RBridge ID of a cluster unit is equal to the domain ID of an FC switch. RBridge ID assignment is implemented by leveraging the domain ID assignment protocols in the FC SANs. Request for Domain ID (RDI) and Domain ID Assignment (DIA) protocols ensure that a single switch (the principal switch) is centrally allocating the domain IDs for every RBridge in the fabric and detecting any domain ID conflicts in the fabric. In case of conflict, the conflicting node is segmented from the fabric. You must take action to resolve the conflict

Network OS 5.0.1 and later support a maximum of 48 RBridges in a single Brocade VCS Fabric, depending on the hardware mix. However, Brocade recommends using only 24 RBridges per fabric.

The following sequence of events describes the Brocade VCS Fabric formation process:

  • Each Brocade VCS Fabric is identified by a VCS ID.
  • All Brocade VCS Fabric-capable switches are configured with a factory default VCS ID of 1.
  • The switch software searches for the value for the "VCS enable" attribute setting and verifies it is set to "enabled".
  • Assuming the switch is Brocade VCS Fabric-enabled, the switch software invokes a series of protocols:
    • Brocade Link Discovery Protocol (BLDP) attempts to discover if a Brocade VCS Fabric-capable switch is connected to any of the edge ports. Refer to Neighbor discovery for more information.
    • BLDP attempts to merge the adjacent Brocade switch into the Brocade VCS Fabric environment at the link level.
  • A series of FC fabric formation protocols (RDI, DIA, and FSPF) are initiated once a link level relationship has been established between two neighbor switches. Refer to Fabric formation for more information.
  • The "Merge and Join" protocol invokes a merge of switch configuration between the cluster units once the fabric has successfully formed.