Brocade FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide - Manual (Page 118)

FIGURE 17 Two data paths from host on an MRP ring to a VSRP-linked device
If a VSRP failover from master to backup occurs, VSRP needs to inform MRP of the topology change;
otherwise, data from the host continues along the obsolete learned path and never reach the VSRP-
linked device, as shown in the following figure.
FIGURE 18 VSRP on MRP rings that failed over
A signaling process for the interaction between VSRP and MRP ensures that MRP is informed of the
topology change and achieves convergence rapidly. When a VSRP node fails, a new VSRP master is
selected. The new VSRP master finds all MRP instances impacted by the failover. Then each MRP
instance does the following:
• The MRP node sends out an MRP PDU with the mac-flush flag set three times on the MRP ring.
• The MRP node that receives this MRP PDU empties all the MAC entries from its interfaces that
participate on the MRP ring.
• The MRP node then forwards the MRP PDU with the mac-flush flag set to the next MRP node that
is in forwarding state.
The process continues until the Master MRP node secondary (blocking) interface blocks the packet.
Once the MAC address entries have been flushed, the MAC table can be rebuilt for the new path from
the host to the VSRP-linked device as shown in the following figure.
Metro Features
118 FastIron Ethernet Switch Platform and Layer 2 Switching Configuration Guide
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