IP Routing Quiz 2

Refer to the exhibit. A router reserved these five routes from different routing information sources. Which two routes does the router install in its routing table? (Choose two)

• RIP route 10.0.0.0/30

• iBGP route 10.0.0.0/30

• OSPF route 10.0.0.0/30

• EIGRP route 10.0.0.1/32

• OSPF route 10.0.0.0/16

Answer explanation

In the five above routes, there are only three different routes which are 10.0.0.0/30 and 10.0.0.0/16 and 10.0.0.1/32. Since each of these routes has a different prefix length (subnet mask), they’re considered different destinations, and they will all be installed in the routing table.

The prefix 10.0.0.0/30 was learned from three different routing protocols IBGP, RIP and OSPF so the route with lowest AD would be chosen. The AD of IBGP is 200 and the AD of RIP is 120 so for the prefix 10.0.0.0/30, only the OSPF route has the lowest AD (110) and it would be chosen to install into the routing table.

A packet is destined for 10.10.1.22. Which static route does the router choose to forward the packet?

• ip route 10.10.1.0 255.255.255.240 10.10.255.1

• ip route 10.10.1.16 255.255.255.252 10.10.255.1

• ip route 10.10.1.20 255.255.255.252 10.10.255.1

• ip route 10.10.1.20 255.255.255.254 10.10.255.1

Answer explanation

The subnet 10.10.1.20/30 covers the destination 10.10.1.22 as this subnet ranges from 10.10.1.20 to 10.10.1.23 so it is the correct answer.

Refer to the exhibit. Router R1 Fa0/0 cannot ping router R3 Fa0/1. Which action must be taken in router R1 to help resolve the configuration issue?

• set the default network as 20.20.20.0/24

• set the default gateway as 20.20.20.2

• configure a static route with Fa0/1 as the egress interface to reach the 20.20.20.0/24 network

• configure a static route with 10.10.10.2 as the next hop to reach the 20.20.20.0/24 network

Refer to the exhibit. Router R1 is running three different routing protocols. Which route characteristic is used by the router to forward the packet that it receives for destination IP 172.16.32.1?

• longest prefix

• metric

• cost

• administrative distance

Answer explanation

A router evaluates routes in the following order.
1. Prefix Length – The longest-matching route is preferred first. Prefix length trumps all other route attributes.
2. Administrative Distance – In the event there are multiple routes to a destination with the same prefix length, the route learned by the protocol with the lowest administrative distance is preferred.
3. Metric – In the event there are multiple routes learned by the same protocol with same prefix length, the route with the lowest metric is preferred. (If two or more of these routes have equal metrics, load balancing across them may occur.)

Router R1 must send all traffic without a matching routing-table entry to 192.168.1.1. Which configuration accomplishes this task?

• R1#config t R1(config)#ip routing R1(config)#ip route default-route 192.168.1.1

• R1#config t R1(config)#ip routing R1(config)#ip route 192.168.1.1 0.0.0.0 0.0.0.0

• R1#config t R1(config)#ip routing R1(config)#ip route 0.0.0.0 0.0.0.0 192.168.1.1

• R1#config t R1(config)#ip routing R1(config)#ip default-gateway 192.168.1.1

Refer to the exhibit. How does router R1 handle traffic to 192.168.12.16?

• It selects the IS-IS route because it has the shortest prefix inclusive of the destination address

• It selects the EIGRP route because it has the lowest administrative distance

• It selects the OSPF route because it has the lowest cost

• It selects the RIP route because it has the longest prefix inclusive of the destination address

R1 has learned route 10.10.10.0/24 via numerous routing protocols. Which route is installed?

• route with the lowest cost

• route with the next hop that has the highest IP

• route with the shortest prefix length

• route with the lowest administrative distance

What are two reasons for an engineer to configure a floating static route? (Choose two)

• to automatically route traffic on a secondary path when the primary path goes down

• to route traffic differently based on the source IP of the packet

• to enable fallback static routing when the dynamic routing protocol fails

• to support load balancing via static routing

• to control the return path of traffic that is sent from the router

Answer explanation

Floating static routes are static routes that have an administrative distance greater than the administrative distance (AD) of another static route or dynamic routes. By default a static route has an AD of 1 then floating static route must have the AD greater than 1. Floating static route has a manually configured administrative distance greater than that of the primary route and therefore would not be in the routing table until the primary route fails.

Refer to the exhibit. A packet is being sent across router R1 to host 172.16.3.14. To which destination does the router send the packet?

• 207.165.200.246 via Serial0/1/0

• 207.165.200.254 via Serial0/0/0

• 207.165.200.254 via Serial0/0/1

• 207.165.200.250 via Serial0/0/0

Refer to the exhibit. Which route type is configured to reach the internet?

• host route

• default route

• floating static route

• network route

Answer explanation

R1 uses the last entry (B* 0.0.0.0/0 …) to reach the Internet. The symbol * means this is a default route.