CCNA 640-802 Exam

QUESTION 91:
Certkiller .com has the following addressing scheme requirements:
-uses a Class B IP address
-currently has 60 subnets
-has a maximum of 1000 computers on any network segment
-needs to leave the fewest unused addresses in each subnet
-uses RIP v1 Which subnet mask is appropriate to use in this network?
A. 255.255.252.0
B. 255.255.248.0
C. 255.255.255.0
D. 255.255.255.128
E. 255.255.255.248
F. 255.255.240.0

Explanation:
A subnet mask of 255.255.255.252 (/22) will result in 6 bits for the network portion and 10 bits for the host portion. This will allow for 2^6 = 64 IP subnets (62 usable), with each one supporting 2^10 = 1024 hosts (1022 usable IP addresses). This meets the requirements of 60 subnets with 1000 maximum hosts per subnet.

In this diagram, OSPF is used as the routing protocol between the corporate office and the offices on the left side of the diagram. An ISDN link provides connectivity from the central corporate router to the remote sales office on the right side of the diagram. Which type of route should the corporate office use to reach the router on the right side of the diagram if the overhead on the ISDN link is to be kept to a minimum?
A. A RIP route
B. An OSPF route
C. A static route
D. A default route
E. A dynamic route
F. None of the above

Explanation:
A static route uses the least amount of overhead because no routing protocol information will be exchanged over the ISDN link. As long as the ISDN link is up, the static route will always remain in the routing table of the corporate router.

Incorrect Answers:
A. This will not only provide additional overhead on the ISDN link as the RIP information is passed from one side to the other, but it will add additional overhead and complexity to the corporate router because now two routing protocols will need to be running. With this choice, RIP and OSPF will need to be configured on the corporate router.
B. This will add the overhead of LSP information being passed between the two routers over the ISDN link.
D. Although a default route can be a type of static route, in this case a default route will be a poor choice because then traffic destined to the Internet will go to remote office on the right side, instead of towards the ISP on the left.
E. All dynamic routing protocols will add some level of overhead. Static routes will not increase the traffic level at all over the ISDN link.

QUESTION 94:
You are a network administrator and you need to implement a routing protocol on your network that provides:
* Scalability
* VLSM support
* Minimal overhead
* Support for connecting networks using routers of multiple vendors Which of the following routing protocol would best serve your needs?
A. VTP
B. RIP version 1
C. EIGRP
D. OSPF
E. IGRP
F. CDP

Explanation:
Since one of the requirements is that the routing protocol must support other vendors, our only choices are RIP and OSPF. Since RIP version 1 does not support VLSM, OSPF is the only choice.

Incorrect Answers:
A. VTP is the VLAN Trunking Protocol. This is not a routing protocol.
B. RIP version one does not support VLSM. Note that RIPv2 does support VLSM, and would be a valid choice.
C, E: EIGRP and IGRP are Cisco proprietary routing protocols, and are not supported by other vendors.
F. CDP is the Cisco Discovery Protocol, which is used to exchange information between Cisco devices. It can only be used between Cisco routers and switches, and it is not a routing protocol.

QUESTION 95:
You need to configure a single router into load balancing traffic across 4 unequal cost paths. Which routing protocols can satisfy this requirement? (Select two)
A. RIP v1
B. RIP v2
C. IGRP
D. EIGRP
E. OSPF
F. IS-IS

Explanation:
In general, load balancing is the capability of a router to distribute traffic over all its network ports that are the same distance from the destination address. Load balancing increases the utilization of network segments, thus increasing effective network bandwidth. There are two types of load balancing: equal cost path and unequal cost path. Every routing protocol supports equal cost path load balancing. In addition to that, IGRP and EIGRP also support unequal cost path load balancing, which is known as variance. The variance command instructs the router to include routes with a metric less than n times the minimum metric route for that destination, where n is the number specified by the variance command. The variable n can take a value between 1 and 128, with the default being 1, which means equal cost load balancing (variance for example.
Traffic is also distributed proportionally among unequal cost links, with respect to the metric.

QUESTION 96:
You need to choose a routing protocol for a new Certkiller network. This network will be running IP, IPX, and Appletalk, and you wish to utilize only one routing protocol. Which one would be the best choice?
A. OSPF
B. EIGRP
C. RIP v2
D. IGRP
E. RIP v1

Explanation:
Only EIGRP provides routing protocol support for IP, IPX, and Appletalk networks.

QUESTION 97:
Which of the routing protocols shown below support both VLSM and route summarization? (Select three)
A. IGRP
B. EIGRP
C. RIP v1
D. RIP v2
E. OSPF
F. VTP
G. CDP

Explanation:
EIGRP and OSPF support Variable Length Subnet Masks (VLSM) and provide for both automatic and manual route summarization configurations. RIPv2 is an enhanced version of RIP, and overcame some of the limitations of RIP by introducing support for VLSM.

Incorrect Answers:
A, C: IGRP and RIP are relatively old and simplistic routing protocols that were developed before the concepts of VLSM and route summarization.
F. VTP is the VLAN Trunking Protocol, used in switched LAN environments to carry VLAN information. It is not a routing protocol.
G. CDP is the Cisco Discovery Protocol, used between neighboring Cisco devices to automatically discover information. It is not a routing protocol.

QUESTION 98:
Which of the following routing protocols support the use of VLSM (Variable Length Subnet Masking)? (Select three)
A. RIPv1
B. EIGRP
C. OSPF
D. IGRP
E. RIPv2

Explanation:
Static routing, OSPF, IS-IS, EIGRP, BGP, and RIP version 2 all support VLSM.

Incorrect Answers:
A, D: RIPv1 and IGRP do not support VLSM.
Reference: Sybex CCNA Study Guide edition 4, Page 123

QUESTION 99:
Which of the following routing protocols do NOT support VLSM (variable length subnet masking)? (Choose all that apply).
A. RIPv1
B. IGRP
C. EIGRP
D. OSPF
E. IS-IS
F. RIPv2

Explanation:
RIP version 1 and IGRP are classful IP routing protocols. They do not support variable length subnet masks. Incorrect Answers:
C, D, E, F. Static routing, OSPF, IS-IS, EIGRP, BGP, and RIP version 2 all support
VLSM.

QUESTION 100:
You need to implement the use of a routing protocol that meets the following requirements:
1. Converges quickly
2. Supports VLSM, CIDR, IP, and IPX.
3. Uses minimal bandwidth for routing updates.
Which one of the following routing protocols would be the best choice?
A. RIPv1
B. RIPv2
C. IGRP
D. OSPF
E. EIGRP

Explanation:
EIGRP would be the best choice as it provides support for VLSM and CIDR, has faster convergence times than other protocols, is scalable, and supports IP, IPX, and Appletalk.
EIGRP is a Cisco proprietary routing protocol, so it will not work with other vendors.
However, the requirements of the question made no mention of the use of non-Cisco routers, so it will not be an issue in this case.

Incorrect Answers:
A, C: Both of these routing protocols do not support VLSM.
B. While RIPv2 supports VLSM, it provides no support for IPX. The IPX RIP protocol is similar in function to RIP version 1. Both versions of RIP also consume more bandwidth than EIGRP.
D. OSPF does not support IPX.