Extreme Networks Px Series, Installation And Configuration Manual

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Px Series Application Switch Installation and Configuration Guide 8-1
8 Configuring Redundancy
This chapter describes how to configure redundancy for the Px series application
switch. For the SummitPx1, you use the industry standard VRRP. For the PxM, you use
the Extreme Standby Router Protocol (ESRP).
The chapter contains the following sections:
• Using VRRP with the SummitPx1 on page 8-1
•
Configuring Redundancy for the PxM on page 8-6
• Configuring a Default Gateway on page 8-8
Using VRRP with the SummitPx1
To reduce downtime, the SummitPx1 supports the deployment of redundant systems
using VRRP, an industry standard failover mechanism (RFC 2338). In the event of the
failure of the primary active system, the secondary system automatically takes over for
the failed system.
VRRP uses a “phantom MAC” address at layer 2, which is negotiated using an election
protocol. After one of the application switches is elected “active,” the application
switches exchange keep-alive messages to ensure that the active system remains up. If
the redundant system loses connectivity for 3 seconds, the redundant system assumes
the active system is dead and it assumes traffic-forwarding duties. It promiscuously
sends ARP responses to poison the layer 2 forwarding information for the previously
active system and begin accepting traffic for the phantom MAC.