Dell PowerConnect B-RX Configuration Manual page 500

15
VSRP and MRP signaling
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 81
To ensure that MRP is informed of the topology change and to achieve convergence rapidly, there is
a signaling process that controls the interaction between VSRP and MRP. 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 process continues until the Master MRP node's 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 82
428
VSRP on MRP rings that failed over
Path 1
MRP
Master
MRP
MRP
Member
MRP Member
VSRP Backup
VSRP
X
Device 1
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 address 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.
New path established
Path 1
MRP
Master
MRP
MRP
Member
MRP Member
VSRP Backup
VSRP
X
Device 1
Figure 81.
MRP
Host
Member
MRP Member
VSRP Master
(Figure 82).
MRP
Host
Member
MRP Member
VSRP Master
Path 2
MRP
Member
MRP MRP
Member
Member
MRP Master
MRP Member
VSRP Backup
VSRP Master
VSRP
X
Device 1
Path 2
MRP
Member
MRP MRP
Member
Member
MRP Master
MRP Member
VSRP Backup
VSRP Master
VSRP
X
Device 1
BigIron RX Series Configuration Guide
MRP
Host
MRP
Host
53-1001810-01