9. Introduction to IP Routing

Question 1

1. Which is not a routing protocol?
   a. RIP
   b. RIPv2
   c. RIPv3
   d. EIGRP

Answer 1

c. Yep, you got it. RIP, RIPv2 and EIGRP are all examples of routing protocols. RIPv3 is nonexistant.

Question 2

2. Which of these best describes dynamic routing?
   a. All network addresses must be hand typed into the routing table.
   b. Only a portion of the network addresses must be hand-typed into the routing table.
   c. Routing tables are updated automatically when changes occur in the network.
   d. A and B

Answer 2

c. In dynamic routing, routers update each other about all the networks they know about and place this information into the routing table. This is possible because a protocol on one router communicates with the same protocol running on neighbour routers. If changes occur in the network, a dynamic routing protocol automatically informs all routers about the events.

Question 3

3. Which is true regarding dynamic routing?
   a. Static routes are best in large networks and thus better to use than dynamic routing protocols.
   b. Static routes are automatically added to the routing table but dynamic routes must be added by hand.
   c. You must use a DNS and WINS server when configuring dynamic routing.
   d. Dynamic routes are automatically added to the routing table.

Answer 3

d. Dynamic routing scales well in large networks and routes are automatically added into the routing table. Static routing is done by hand, one route at a time into each router.

Question 4

4. Which of the following is true of MAC addresses?
   a. MAC addresses are never local on the LAN and always pass through a router.
   b. MAC addresses are always local on the LAN and never go through or past a router.
   c. MAC addresses will always be the IP address of the Fa0/0 interface.
   d. None of the above.

Answer 4

b. Media Access Control (MAC) addresses are always local on the LAN and never go through or past a router.

Question 5

5. What is it called when protocols update their forwarding tables after changes have occurred?
   a. Name resolution
   b. Routing
   c. Convergence
   d. ARP resolution

Answer 5

c. Routing convergence is the time required by the routing protocols to update the routing tables (forwarding tables) on all routers in the network.

Question 6

6. What command would be used to view the ARP cache on your host?
   a. C:> show ip route
   b. C:> show ip arp
   c. C:> show protocols
   d. C:> arp -a

Answer 6

d. The arp -a command will show the ARP cache on your host.

Question 7

7. What happens when a router receives a packet for a network that isn’t listed in the routing table?
   a. It forwards the packet to the next available router.
   b. It holds the packet until the address is updated in the routing table.
   c. The router will use RIP to inform the host that it can’t send the packet.
   d. None of the above.

Answer 7

d. Hope you answered d! A router will not send a broadcast looking for the remote network - the router will discard the packet.

Question 8

8. Which of the following is not a distance vector protocol?
   a. RIPv1
   b. RIPv2
   c. OSPF
   d. IGRP

Answer 8

c. RIPv1 and 2 and IGRP are all distance vector (DV) protocols. Routers using a DV protocol send all or parts of their routing table in a routing update message at a regular interval to each of their neighbour routers.

Question 9

9. Which two of the following are link-state protocols?
   a. RIPv1
   b. RIPv2
   c. OSPF
   d. IS-IS
   e. IGRP

Answer 9

c, d. Open Shortest Path First (OSPF) and Intermediate System-to-Intermediate System (IS-IS) are link-state (LS) routing protocols.

Question 10

10. Which of the following is a hybrid routing protocol?
    a, RIPv2
    b. EIGRP
    c. IS-IS
    d. IGRP

Answer 10

b. The only protocol you could select is Enhanced Interior Gateway Routing Protocol (EIGRP).

Question 11

11. What does the acronym EIGRP stand for?
    a. Enhanced Interior Gateway Routing Protocol
    b. Enhanced Inside Gateway Redundancy Protocol
    c. Enhanced Interior Group Reliability Protocol
    d. Enhanced Interior Gateway Redundancy Protocol

Answer 11

a. Interior Gateway Routing Protocol is a distance-vector (DV) interior gateway protocol.

Question 12

12. What EGP protocol is used on the Internet?
    a. GGP
    b. EGP
    c. BGP
    d. IGP

Answer 12

c. Border Gateway Protocol (BGP) is the most popular choice for ISPs or really large corporates.

Question 13

13. What are the two categories of IGP protocols? (choose two)
    a. Link state
    b. Static
    c. Distance vector
    d. EGP

Answer 13

a, c. Distance-vector (DV) and link-state (LS) are the two routing protocols to remember.

Question 14

14. What two pieces of information does a router require to make a routing decision? (choose two)
    a. Destination network (address)
    b. Destination MAC address
    c. Application layer protocol
    d. Neighbour router

Answer 14

a, d. A frame uses a local MAC address (router) to send a packet on the LAN. The frame will take the packet to either a host on the LAN or a router’s interface if the packet is destined for a remote network, which would be sent to the neighbour router.

Question 15

15. Where does a frame have to carry a packet to if it is destined for a remote network?
    a. Default gateway
    b. Neighbour host
    c. Switch
    d. Hub

Answer 15

a. I hope you said A! Packets specifically have to be carried to a router in order to be routed through a network.

Question 16

16. Where along the IP routing process does a packet get changed?
    a. Router
    b. Host A
    c. Destination device
    d. Host B

Answer 16

c. Remember that the frame changes at each hop but that the packet is never changed in any way until it reaches the destination device.

Question 17

17. When all routers in a network agree about the path from one point to another, the network is said to be what?
    a. Dynamic
    b. Static
    c. Happy
    d. Converged

Answer 17

d. When the routing tables are complete because they include information about all networks in the internetwork, they are considered converged.

Question 18

18. What type of request must a client send if it does not know the destination MAC address?
    a. ARP broadcast
    b. Multicast
    c. ICMP redirect
    d. Reverse ARP

Answer 18

a. This is step 6 in the IP routing process. If the hardware address isn’t in the ARP cache of the host, an ARP broadcast is sent out on to the local network to search for the hardware address.

Question 19

19. You need to perform maintenance on a router in your corporate office. It is important that the network does not go down. What can you do to accomplish your goal?
    a. Configure BGP on the router
    b. Implement NAT on the router
    c. Configure on your router a static route that temporarily reroutes traffic through another office.
    d. Implement convergence on the router.

Answer 19

c. The best answer is to reroute traffic using a temporary static route until the maintenance is complet on the router.

Question 20

20. When are you most likely to see a Request Timed Out message?
    a. When an unknown error has occurred.
    b. When you have used the arp -a command incorrectly
    c. When a known error has occurred
    d. When you are using a hybrid routing protocol.

Answer 20

a. You are most likely to see a Request Timed Out message when (if) a packet is lost on the way back to the originating host for an unknown error. Remember, if the error occurs because of a known issue, you are likely to see a Destination Unreachable message.