Hsrp Overview; Chapter 19 Configuring Hsrp - Cisco Nexus 7000 Series Configuration Manual

Information About HSRP
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .
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HSRP Overview

When you use HSRP, you configure the HSRP
the IP address of the actual router). The virtual IP address is an IP address that is shared among a group
of routers that run HSRP.
When you configure HSRP on a network segment, you provide a
address for the HSRP group. You configure the same virtual address on each HSRP-enabled interface in
the group. You also configure a unique IP address and MAC address on each interface that acts as the
real address. HSRP selects one of these interfaces to be the
routes packets destined for the virtual MAC address of the group.
HSRP detects when the designated active router fails. At that point, a selected
control of the virtual MAC and IP addresses of the HSRP group. HSRP also selects a new standby router
at that time.
HSRP uses a priority mechanism to determine which HSRP-configured interface becomes the default
active router. To configure an interface as the active router, you assign it with a priority that is higher
than the priority of all the other HSRP-configured interfaces in the group. The default priority is 100, so
if you configure just one interface with a higher priority, that interface becomes the default active router.
Interfaces that run HSRP send and receive multicast User Datagram Protocol (UDP)-based hello
messages to detect a failure and to designate active and standby routers. When the active router fails to
send a hello message within a configurable period of time, the standby router with the highest priority
becomes the active router. The transition of packet forwarding functions between the active and standby
router is completely transparent to all hosts on the network.
You can configure multiple HSRP groups on an interface.
Figure 19-1
address, two or more interfaces can act as a single
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
19-2
HSRP Messages, page 19-4
HSRP Load Sharing, page 19-4
Object Tracking and HSRP, page 19-5
vPC and HSRP, page 19-5
High Availability and Extended Non-Stop Forwarding, page 19-6
Virtualization Support, page 19-6
shows a network configured for HSRP. By sharing a virtual MAC address and a virtual IP
virtual IP address as the host's default router (instead of
virtual MAC address
active router. The active router receives and
virtual router.
Chapter 19 Configuring HSRP
and a virtual IP
standby router assumes
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