418 BigIron RX Series Configuration Guide53-1001986-01Overview of Virtual Switch Redundancy Protocol (VSRP)15Following Master election (described below), one of the Brocade devices becomes the Master forthe VRID and sets the state of all the VLAN’s ports to Forwarding. The other device is a Backup andsets all the ports in its VRID VLAN to Blocking.If a failover occurs, the Backup becomes the new Master and changes all its VRID ports to theForwarding state.Other Brocade devices can use the redundant paths provided by the VSRP devices. In this example,three Brocade devices use the redundant paths. A Brocade device that is not itself configured forVSRP but is connected to a Brocade device that is configured for VSRP, is VSRP aware. In thisexample, the three Brocade devices connected to the VSRP devices are VSRP aware. A Brocadedevice that is VSRP aware can failover its link to the new Master in sub-second time, by changingthe MAC address associated with the redundant path.When you configure VSRP, make sure each of the non-VSRP Brocade devices connected to theVSRP devices has a separate link to each of the VSRP devices.When using the BigIron RX in conjunction with a FastIron Edge Switch, FastIron GS Series Switch,FastIron LS Series Switch, FastIron Edge Switch X Series Switch, or the FastIron Edge Switch XSeries Switch as the VSRP-aware switches, the vsrp-aware vrid tc-vlan-flush command isrequired to be configured on the non-BigIron RX devices. Refer to the FastIron Configuration Guidefor additional information.Layer 2 and Layer 3 redundancyYou can configure VSRP to provide redundancy for Layer 2 only or both for Layer 2 and Layer 3:• Layer 2 only – The Layer 2 links are backed up but specific IP addresses are not backed up.• Layer 2 and Layer 3 – The Layer 2 links are backed up and a specific IP address is also backedup. Layer 3 VSRP is the same as VRRPE. However, using VSRP provides redundancy at bothlayers at the same time.Master election and failoverEach VSRP device advertises its VSRP priority in Hello messages. During Master election, the VSRPdevice with the highest priority for a given VRID becomes the Master for that VRID. After Masterelection, the Master sends Hello messages at regular intervals to inform the Backups that theMaster is healthy.If there is a tie for highest VSRP priority, the tie is resolved as follows:• The device whose virtual routing interface has a higher IP address becomes the master.• If no IP address is configured, the device’s base MAC address is used.VSRP failoverEach Backup listens for Hello messages from the Master. The Hello messages indicate that theMaster is still available. If the Backups stop receiving Hello messages from the Master, the electionprocess occurs again and the Backup with the highest priority becomes the new Master.
