Quick Reference Guide

PowerConnect B-Series TI24X Configuration Guide 243
53-1002269-02
Virtual Switch Redundancy Protocol (VSRP)
8
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 Figure 51.
FIGURE 51 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 (Figure 52).
FIGURE 52 New path established
X
X
Path 1
Path 2
MRP
Member
MRP
Master
MRP
Member
MRP
Member
MRP
MRP Member
VSRP Backup
VSRP
Host
MRP Member
VSRP Master
MRP
Member
MRP
Member
MRP
MRP Master
VSRP Backup
VSRP
MRP Member
VSRP Master
Device 1
Device 1
Host
X
X
Path 1
Path 2
MRP
Member
MRP
Master
MRP
Member
MRP
Member
MRP
VSRP Backup
VSRP
Host
VSRP Master
MRP
Member
MRP
Member
MRP
VSRP Backup
VSRP
VSRP Master
Device 1
Device 1
Host
MRP
Member
MRP
Member
MRP
Master
MRP
Member