Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 82)

FIGURE 8 Metro ring - ring break
If a break in the ring occurs, MRP heals the ring by changing the states of some of the ring interfaces:
• Blocking interface - The Blocking interface on the Master node has a dead timer. If the dead time
expires before the interface receives one of its ring RHPs, the interface changes state to
Preforwarding. Once the secondary interface changes state to Preforwarding:
‐ If the interface receives an RHP, the interface changes back to the Blocking state and
resets the dead timer.
‐ If the interface does not receive an RHP for its ring before the Preforwarding time expires,
the interface changes to the Forwarding state, as shown in
Figure 8 .
• Forwarding interfaces - Each member interface remains in the Forwarding state.
When the broken link is repaired, the link interfaces come up in the Preforwarding state, which allows
RHPs to travel through the restored interfaces and reach the secondary interface on the Master node:
Metro Features
82 FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide
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