Layer 2 And Layer 3 Redundancy; Master Election And Failover - Dell PowerConnect B-RX Configuration Manual

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Overview of Virtual Switch Redundancy Protocol (VSRP)
Following Master election (described below), one of the Brocade devices becomes the Master for
the VRID and sets the state of all the VLAN's ports to Forwarding. The other device is a Backup and
sets 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 the
Forwarding 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 for
VSRP but is connected to a Brocade device that is configured for VSRP, is VSRP aware. In this
example, the three Brocade devices connected to the VSRP devices are VSRP aware. A Brocade
device that is VSRP aware can failover its link to the new Master in sub-second time, by changing
the MAC address associated with the redundant path.
When you configure VSRP, make sure each of the non-VSRP Brocade devices connected to the
VSRP 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 X
Series Switch as the VSRP-aware switches, the vsrp-aware vrid <num> tc-vlan-flush command is
required to be configured on the non-BigIron RX devices. Refer to the FastIron Configuration Guide
for additional information.

Layer 2 and Layer 3 redundancy

You can configure VSRP to provide redundancy for Layer 2 only or both for Layer 2 and Layer 3:
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•

Master election and failover

Each VSRP device advertises its VSRP priority in Hello messages. During Master election, the VSRP
device with the highest priority for a given VRID becomes the Master for that VRID. After Master
election, the Master sends Hello messages at regular intervals to inform the Backups that the
Master is healthy.
If there is a tie for highest VSRP priority, the tie is resolved as follows:
•
•
VSRP failover
Each Backup listens for Hello messages from the Master. The Hello messages indicate that the
Master is still available. If the Backups stop receiving Hello messages from the Master, the election
process occurs again and the Backup with the highest priority becomes the new Master.
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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 backed
up. Layer 3 VSRP is the same as VRRPE. However, using VSRP provides redundancy at both
layers at the same time.
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.
BigIron RX Series Configuration Guide
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