Routing Protocols

Question 1

Which of the following protocols support VLSM, summarization, and discontiguous networking? (Choose three.)

RIPv1

IGRP

EIGRP

OSPF

BGP

RIPv2

Answer 1

EIGRP

OSPF

RIPv2

RIPv1 and IGRP are true distance vector routing protocols and can’t do much, really—except build and maintain routing tables and use a lot of bandwidth! RIPv2, EIGRP, and OSPF build and maintain routing tables, but they also provide classless routing, which allows for VLSM, summarization, and discontiguous networking

Question 2

Which of the following are considered distance vector routing protocols? (Choose two.)

OSPF

RIP

RIPv2

IS-IS

Answer 2

RIP

RIPv2

RIP and RIPv2 are distance vector routing protocols. OSPF and IS-IS are link state

Question 3

Which of the following are considered link state routing protocols? (Choose two.)

OSPF

RIP

RIPv2

IS-IS

Answer 3

OSPF

IS-IS

RIP and RIPv2 are distance vector routing protocols. OSPF and IS-IS are link state

Question 4

Which of the following is considered a hybrid routing protocol? (Choose two.)

OSPF

BGP

RIPv2

IS-IS

EIGRP

Answer 4

BGP

EIGRP

RIP and RIPv2 are distance vector routing protocols. OSPF and IS-IS are link state. EIGRP uses qualities from both distance vector and link state to create a hybrid routing protocol. BGP can be used as an EGP and IGP, and the objectives consider BGP a hybrid routing protocol

Question 5

Why would you want to use a dynamic routing protocol instead of using static routes?

There is less overhead on the router.

Dynamic routing is more secure.

Dynamic routing scales to larger networks.

Answer 5

Dynamic routing scales to larger networks.

Dynamic routing is typically used in today’s networks because it scales to larger networks and takes less administrative work

Question 6

Which of the following is a vendor-specific FHRP protocol?

EIGRP

IS-IS

HSRP

Answer 6

HSRP

Hot Standby Router Protocol (HSRP) is Cisco’s FHRP

Question 7

RIP has a long convergence time and users have been complaining of response time when a router goes down and RIP has to reconverge. Which can you implement to improve convergence time on the network?

Replace RIP with static routes.

Update RIP to RIPv2.

Update RIP to OSPF using link state.

Answer 7

Update RIP to OSPF using link state.

Static routes may be a good solution, but remember that they are not dynamic, and if a piece of equipment goes down, new routes to remote networks will not automatically update, so OSPF is the best answer. It dynamically will update the routing tables with faster convergence than RIP

Question 8

What is the administrative distance of OSPF?

90

100

110

Answer 8

110

The administrative distance (AD) is a very important parameter in a routing protocol. The lower the AD, the more trusted the route. If you have IGRP and OSPF running, by default IGRP routes would be placed in the routing table because IGRP has a lower AD of 100. OSPF has an AD of 110. RIPv1 and RIPv2 both have an AD of 120, and EIGRP is the lowest at 90

Question 9

Which of the following protocols will advertise routed IPv6 networks?

RIP

RIPng

OSPFv2

Answer 9

RIPng

The routing protocols that have been upgraded to advertise IPv6 routes are RIPng, OSPFv3, and EIGRPv6. IS-IS can advertise IPv6 routes as well, but no upgrade was needed for IS-IS

Question 10

What is the difference between static and dynamic routing?

You use static routing in large, scalable networks.

Dynamic routing is used by a DNS server.

Dynamic routes are added automatically.

Answer 10

Dynamic routes are added automatically.

Dynamic routing protocols, like RIP, EIGRP and OSPF, automatically add route updates to the routing table. Static routes must be added by hand

Question 11

Which routing protocol has a maximum hop count of 15?

RIPv1

IGRP

EIGRP

Answer 11

RIPv1

The distance vector protocols RIPv1 and RIPv2 both have a maximum hop count of 15 (remember, 16 is unreachable). IGRP and EIGRP have a hop count of 255, and OSPF doesn’t have a maximum hop count

Question 12

Which of the following describes routing convergence time?

The time it takes for your VPN to connect

The time required by protocols to update their forwarding tables after changes have occurred

The time required for IDS to detect an attack

Answer 12

The time required by protocols to update their forwarding tables after changes have occurred

Routing convergence time is the time for all routers to update their routing tables (forwarding tables)

Question 13

What routing protocol is typically used to connect ASs on the Internet?

IGRP

RIPv2

BGP

Answer 13

BGP

BGP is used to connect autonomous systems together on the Internet because of its ability to make classless routing and summarization possible. This helps to keep routing tables smaller and more efficient at the ISP core

Question 14

RIPv2 sends out its routing table every 30 seconds just like RIPv1, but it does so more efficiently. What type of transmission does RIPv2 use to accomplish this task?

Broadcasts

Multicasts

Telecast

Answer 14

Multicasts

RIPv1 sends broadcasts every 30 seconds and has an AD of 120. RIPv2 sends multicasts (224.0.0.9) every 30 seconds and also has an AD of 120. RIPv2 sends subnet-mask information with the route updates, which allows it to support classless networks and noncontiguous networks. RIPv2 also supports authentication between routers; RIPv1 does not

Question 15

Which routing protocols have an administrative distance of 120? (Choose two.)

RIPv1

RIPv2

EIGRP

OSPF

Answer 15

RIPv1

RIPv2

Both RIPv1 and RIPv2 have an AD of 120. EIGRP has an AD of 90 and OSPF is 110

Question 16

Which of the following routing protocols uses AS-Path as one of the methods to build the routing tables?

OSPF

IS-IS

BGP

Answer 16

BGP

Border Gateway Protocol (BGP) attributes include the IP address to get to the next AS (the next-hop attribute) as well as an indication of how the networks at the end of the path were introduced into BGP (the origin code attribute). The AS path information is useful to construct a graph of loop-free autonomous systems and is used to identify routing policies so that restrictions on routing behavior can be enforced based on the AS path

Question 17

Which IPv6 routing protocol uses UDP port 521?

RIPng

EIGRPv6

OSPFv3

Answer 17

RIPng

RIPng, which uses port 521, has many of the same features as RIPv2: It’s a distance vector protocol; it has a max hop count of 15; and it uses split horizon, poison reverse, and other loop-avoidance mechanisms. And it still uses multicast to send its updates, too, but in IPv6, it uses FF02::9 for the transport address. For RIPv2, the multicast address was 224.0.0.9, so the address still has a 9 at the end in the new IPv6 multicast range

Question 18

What EIGRP information is held in RAM and maintained through the usage of hello and update packets? (Select all that apply.)

DUAL table

Neighbor table

Topology table

Successor route

Answer 18

Neighbor table

Topology table

EIGRP holds three tables in RAM: neighbor, topology, and routing. The neighbor and topology tables are built and also maintained with the use of hello packets

Question 19

Which is true regarding EIGRP successor routes?

Successor routes are stored in the DUAL table.

Successor routes are used only if the primary route fails.

A successor route is used by EIGRP to forward traffic to a destination

Answer 19

A successor route is used by EIGRP to forward traffic to a destination

A successor route (think “successful” rather than standby or backup) is used by EIGRP to forward traffic to a destination and is stored in the routing table. It is backed up by a feasible successor route that is stored in the topology table—if one is available. Remember that all routes are in the topology table

Question 20

Which of the following uses only hop count as a metric to find the best path to a remote network?

RIP

EIGRP

OSPF

Answer 20

RIP

RIP and RIPv2 use only hop count as a metric, with a maximum of 15 hops, to find the best path to a remote network