Dell PowerConnect B-RX BigIron RX Series Configuration Guide v02.8.00 - Page 482

14 How ring breaks are detected and healed How ring breaks are detected and healed Figure 67 Shows the ring forwarding state following a link break. MRP quickly heals the ring and preserves connectivity among the customer networks. FIGURE 67 Metro ring - ring break Customer A F F F Switch B F F Customer A Switch C F Master Switch A Node F F Customer A Switch D F F Customer A 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's 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 67. • Forwarding interfaces - Each member interface remains in the Forwarding state. 406 BigIron RX Series Configuration Guide 53-1002253-01