200-301 test

200-301 test.Tip: Medium to large enterprise networks are struggling to find a balance between Kor-availability features and available budget. The Cisco website has a number of design documents that discuss the tradeoffs of high availability design. If you are interested in learning more, search for "High Availability Campus Network Design" at cisco.com.The Need for First-Hop Redundancy ProtocolsNow we return to the topic of this chapter. So far, the only design given in this chapter has two routers on the LAN on the left side of the diagram, specifically the same VLAN and subnet, as the design in Figure 6-3. Despite the benefits of having redundant routers on the same subnets, the network still needs to use FHRP when these redundant devices exist0To understand the need and benefits of using FHRP, first think about how hosts in VLAN10/subnet 10.1.1.0/24 use these redundant devices as default routers. The host logic remains the same, with each host having a single default router setting. In this way, some of the design options for that default router setting contain the following.2.2 Base Content 130All hosts in the subnet use Rl (10.1.1.9) as their default router, and if R1 fails, reconfigure their default router setting to R2's l0.l.l29o All hosts in the subnet use R2 (10.1.1.129) as their default router, and if R2 fails, reconfigure their default router setting by statically The setting is 10.1.1.9 for R1. Half of the hosts use R1, and the other half use R2, as their respective default routers, and if either router fails, then that half of the users reconfigure their default router settings by static means.To ensure that this concept is clear, Figure 6-4 gives a third design option, with half of the hosts using R1 and the other half using R2O To show this concept more clearly, all LAN switches have been removed from the figure. Hosts A and B use R1 as the default router, and hosts C and D use R2 as the default router.VLAN10,subnet 10.1.1.0/24Figure 6-4 Traffic balancing by assigning different default routers to different clientsThere is a problem with all of these design options: users have to take action. They have to know out of the blue, they have to know how to reconfigure the default router settings, and they have to know when to change back to the initial settings. the FHRP makes this design option work much more smoothly. The two routers look like a single default router. Users never have to do anything: their default router settings stay the same, and even their ARP tables stay the same.