Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 525)

Multi-Service IronWare Switching Configuration Guide 495
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MRP Phase 2
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FIGURE 120 Expected switching path with shared interface
RHP processing in rings with shared interfaces
Interfaces on an MRP ring have one of the following states:
• Blocking (B) – The interface can process RHPs, but cannot forward data for the ring. Only the
secondary interface on the Master node can be blocking. If the interface receives RHP’s for
lower priority rings these RHPs will be discarded by this interface. This prevents RHP’s from
lower priority rings from looping in the topology.
• Preforwarding (PF) – The interface will forward RHPs but won’t forward data for the ring. All ring
interfaces start in this state when you enable MRP. A blocking interface transitions to
preforwarding when the preforwarding timer expires.
• Forwarding (F) – The interface will forward RHP’s and data for the ring. On member switches an
interface transitions from preforwarding to forwarding when the preforwarding time expires or
the interface receives an RHP with the forwarding bit set. A break in the ring is indicated if the
secondary interface on the master fails to receive an RHP within the preforwarding timer and
the interface transitions from blocking to forwarding to heal the ring. The preforwarding time is
the number of milliseconds the interface will remain in the preforwarding state before
changing to the Forwarding state, even without receiving an RHP.