nx.os.and.cisco.nexus.switching.2nd.edition.1587143046

HSRP
• Virtual Router Redundancy Protocol (VRRP)
• Gateway Load Balancing Protocol (GLBP)
HSRP is a Cisco innovation introduced to the networking world in 1998 and described in
RFC 2281. HSRP enables two or more routers to provide first-hop redundancy services for
IP traffic. In HSRP, a virtual IP address is configured and is “owned” by one of the routers
participating in the HSRP group to represent the default gateway for a given subnet. If that
router fails or is taken out of service, the second router assumes the role of the default
gateway using the same Media Access Control (MAC) address. This prevents the hosts on
the network from needing to send an Address Resolution Protocol (ARP) for the new
gateway’s MAC address, and traffic is passed with minimal to no disruption.
HSRP is supported on both the Nexus 7000 and 5500 series switches. The examples in this
chapter focus on HSRP configuration for the Nexus 7000.
HSRP Configuration
The first step to configure HSRP is to enable it in global configuration mode using the
feature command, as demonstrated in Example 3-88. With the modular nature of NX-OS,
using the feature command loads the HSRP modular code into memory for execution.
Without the feature enabled, it would not be resident in memory.
Figure 3-11 illustrates the topology used in Examples 3-100 through 3-110.
Figure 3-11. Network Topology for HSRP Configuration
Example 3-100. Enabling the HSRP Feature
Click here to view code image
Congo# config t
Enter configuration commands, one per line. End with
CNTL/Z.
Congo(config)# feature hsrp
Congo(config)# end
Congo# show run hsrp
!Command: show running-config hsrp
!Time: Sun Oct 11 21:44:42 2009