Configuration Guide User guide

656 FastIron Configuration Guide
53-1002494-02
VSRP
VSRP and MRP signaling
A device may connect to an MRP ring through VSRP to provide a redundant path between the
device and the MRP ring. VSRP and MRP signaling ensures rapid failover by flushing MAC
addresses appropriately. The host on the MRP ring learns the MAC addresses of all devices on the
MRP ring and VSRP link. From these MAC addresses, the host creates a MAC database (table),
which is used to establish a data path from the host to a VSRP-linked device. Figure 56 below
shows two possible data paths from the host to Device 1.
FIGURE 56 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 Figure 57.
FIGURE 57 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:
Path 1
Path 2
MRP
Member
MRP
Master
MRP
Member
MRP
Member
MRP
VSRP Master
VSRP
Host
VSRP Backup
MRP
Member
MRP
Member
MRP
VSRP Master
VSRP
VSRP Backup
Device 1
Device 1
Host
MRP
Member
MRP
Member
MRP
Master
MRP
Member
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