642-813 Q&A – Implement High Availability (1-5)

Section 5 – Implement High Availability, given a network design and a set of requirements

QUESTION NO: 1
In which three HSRP states do routers send hello messages? (Choose three.)
A.standby
B.learn
C.listen
D.speak
E.active
Answer: A D E

Explanation:
When HSRP is configured on an interface, the router progresses through a series of states before becoming active. This forces a router to listen for others in a group and see where it fits into the pecking order. The HSRP state sequence is Disabled, Init, Listen, Speak, Standby, and, finally, Active.
Only the standby (second highest priority) router monitors the hello messages from the active router. By default, hellos are sent every 3 seconds. If hellos are missed for the duration of the holdtime timer (default 10 seconds, or 3 times the hello timer), the active router is presumed down.
The standby router is then clear to assume the active role. If other routers are sitting in the Listen state, the next-highest priority router is allowed to become the new standby router.

QUESTION NO: 2
Drag and drop question. Drag the items to the proper locations.

Answer:

QUESTION NO: 3
Which two characteristics apply to Cisco Catalyst 6500 Series Switch supervisor redundancy using NSF? (Choose two.)
A. supported by RIPv2, OSPF, IS-IS, and EIGRP
B. dependent on FIB tables
C. supports IPv4 and IPv6 multicast
D. prevents route flapping
E. independent of SSO
F. NSF combined with SSO enables supervisor engine load balancing
Answer: BD
Explanation:
The purpose of NSF is to enable the Layer 3 switch to continue forwarding packets from an NSFcapable neighboring router when the primary route processor (RP) is failing and the backup RP is taking over. So it prevents the route flapping and it depends on FIB (Forwarding Information Base)
table.

QUESTION NO: 4
HSRP has been configured between two Pass4sure devices. Which of the following describe reasons for deploying HSRP? (Select all that apply)
A. HSRP provides redundancy and fault tolerance
B. HSRP allows one router to automatically assume the function of the second router if the second router fails
C. HSRP allows one router to automatically assume the function of the second router if the second router starts
D. HSRP provides redundancy and load balancing
Answer: ABD
Explanation:
One way to achieve near-100 percent network uptime is to use HSRP, which provides network redundancy for IP networks, ensuring that user traffic immediately and transparently recovers from first hop failures in network edge devices or access circuits.
By sharing an IP address and a MAC (Layer 2) address, two or more routers can act as a single "virtual" router. The members of the virtual router group continually exchange status messages.
This way, one router can assume the routing responsibility of another, should it go out of commission for either planned or unplanned reasons. Hosts continue to forward IP packets to a consistent IP and MAC address, and the changeover of devices doing the routing is transparent.
Through the use of multiple HSRP standby groups, traffic can be load balanced between the HSRP routers. For example, users on one VLAN could use one router as the primary HSRP router, and users on another VLAN can use the other HSRP router as the primary.

QUESTION NO: 5
Refer to the exhibit and the partial configuration on routers R1 and R2. Hot Standby Routing
Protocol (HSRP) is configured on the network to provide network redundancy for the IP traffic. The network administrator noticed that R2 does not become active when the R1 serial0 interface goes down. What should be changed in the configuration to fix the problem?

A.R2 should be configured with a HSRP virtual address.
B.R2 should be configured with a standby priority of 100.
C.The Serial0 interface on router R2 should be configured with a decrement value of 20.
D.The Serial0 interface on router R1 should be configured with a decrement value of 20.
Answer: D
Explanation:
You can configure a router to preempt or immediately take over the active role if its priority is the highest at any time. Use the following interface configuration command to allow preemption:

Switch(config-if)# standby group preempt [delay seconds]

By default, the router can preempt another immediately, without delay. You can use the delay keyword to force it to wait for seconds before becoming active. This is usually done if there are routing protocols that need time to converge.