Specifications

CHAPTER
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14-1
Cisco Nexus 3000 Series NX-OS Unicast Routing Configuration Guide, Release 5.0(3)U2(2)
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Configuring HSRP
This chapter describes how to configure the Hot Standby Router Protocol (HSRP) on the Cisco NX-OS
switch.
This chapter includes the following sections:
• Information About HSRP, page 14-1
• Licensing Requirements for HSRP, page 14-6
• Prerequisites for HSRP, page 14-6
• Guidelines and Limitations, page 14-6
• Default Settings, page 14-6
• Configuring HSRP, page 14-7
• Verifying the HSRP Configuration, page 14-16
• Configuration Examples for HSRP, page 14-16
• Additional References, page 14-16
• Feature History for HSRP, page 14-17
Information About HSRP
HSRP is a first-hop redundancy protocol (FHRP) that allows a transparent failover of the first-hop IP
router. HSRP provides first-hop routing redundancy for IP hosts on Ethernet networks configured with
a default router IP address. You use HSRP in a group of routers for selecting an active router and a
standby router. In a group of routers, the active router is the router that routes packets; the standby router
is the router that takes over when the active router fails or when preset conditions are met.
Many host implementations do not support any dynamic router discovery mechanisms but can be
configured with a default router. Running a dynamic router discovery mechanism on every host is not
feasible for a number of reasons, including administrative overhead, processing overhead, and security
issues. HSRP provides failover services to these hosts.
This section includes the following topics:
• HSRP Overview, page 14-2
• HSRP for IPv4, page 14-3
• HSRP Versions, page 14-4
• HSRP Authentication, page 14-4