Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 529)

Multi-Service IronWare Switching Configuration Guide 499
53-1003036-02
MRP Phase 2
14
Flow when a link breaks
Referring to Figure 123 if the link between S1 and S2 fails, the secondary interface on the ring 1
master node changes to a forwarding state.
The RHPs from the master for ring 2 reach S2 and a copy of the RHP is forwarded out of e 2/1. This
RHP traverses the ring 1 master and continues around ring 1 until it reaches S1. After S1 the RHP
is back on ring 2 and is finally received by the master for ring 2 which keeps its secondary interface
in blocking mode.
It should now be clear how the flow of lower priority RHPs over the higher priority ring ensure that
both ring masters do not transition to forwarding and create a loop condition.
FIGURE 123 Flow of RHP packets when a link for shared interfaces breaks
Ring 2 RHPs follow this path until the link is restored. Once the link is restored the ring 1 master will
transition its secondary ring interface to blocking and the ring 2 RHP flow is as shown in
Figure 122 .
NOTE
There should always be a layer 2 protocol configured in the default vlan when MRP is configured with
all dual mode ports.