[2021-New] Cisco 100-105 Dumps With Update Exam Questions (41-50)

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Q1. - (Topic 5)

An administrator has connected devices to a switch and, for security reasons, wants the dynamically learned MAC addresses from the address table added to the running configuration.

What must be done to accomplish this?

A. Enable port security and use the keyword sticky.

B. Set the switchport mode to trunk and save the running configuration.

C. Use the switchport protected command to have the MAC addresses added to the configuration.

D. Use the no switchport port-security command to allow MAC addresses to be added to the configuration.

Answer: A

Explanation:

http://www.cisco.com/en/US/docs/switches/lan/catalyst6500/ios/12.2SX/configuration/guide

/port_sec.pdf

One can configure MAC addresses to be sticky. These can be dynamically learned or manually configured, stored in the address table, and added to the running configuration. If these addresses are saved in the configuration file, the interface does not need to dynamically relearn them when the switch restarts, hence enabling security as desired.

Q2. - (Topic 3)

Which statement describes the process ID that is used to run OSPF on a router?

A. It is globally significant and is used to represent the AS number.

B. It is locally significant and is used to identify an instance of the OSPF database.

C. It is globally significant and is used to identify OSPF stub areas.

D. It is locally significant and must be the same throughout an area.

Answer: B

Explanation:

The Process ID for OSPF on a router is only locally significant and you can use the same number on each router, or each router can have a different number-it just doesn't matter. The numbers you can use are from 1 to 65,535. Don't get this confused with area numbers, which can be from 0 to 4.2 billion.

Q3. - (Topic 3)

Which three approaches can be used while migrating from an IPv4 addressing scheme to an IPv6 scheme? (Choose three)

A. static mapping of IPv4 address to IPv6 addresses

B. configuring IPv4 tunnels between IPv6 islands

C. use DHCPv6 to map IPv4 addresses to IPv6 addresses

D. use proxying and translation (NAT-PT) to translate IPv6 packets into IPv4 packets

E. configure IPv6 directly

F. enable dual-stack routing

Answer: B,D,F

Explanation:

Connecting IPv6 islands with tunnels An IPv6 island is a network made of IPv6 links directly connected by IPv6 routers. In the early days of IPv6 deployment, there are many IPv6 islands. IPv6 in IPv4 tunnels are used to connect those islands together. In each island, one (or more) dual stack routers are designated to encapsulate and decapsulate IPv6 packets within IPv4 packets. Different mechanisms have been developed to manage tunnels: automatic tunnels3, configured tunnels3, tunnel brokers3, 6over43, 6to43,... Reference 2: http://www.petri.co.il/ipv6-transition.htm Network Address Translation - Protocol Translation (NAT-PT) The NAT-PT method enables the ability to either statically or dynamically configure a translation of a IPv4 network address into an IPv6 network address and vice versa. For those familiar with more typically NAT implementations, the operation is very similar but includes a protocol translation function. NAT-PT also ties in an Application Layer Gateway (ALG) functionality that converts Domain Name System (DNS) mappings between protocols.

Dual Stack The simplest approach when transitioning to IPv6 is to run IPv6 on all of the devices that are currently running IPv4. If this is something that is possible within the organizational network, it is very easy to implement. However, for many organizations, IPv6 is not supported on all of the IPv4 devices; in these situations other methods must be considered.

Reference: http://www.opus1.com/ipv6/howdoitransitiontoipv6.html

Q4. - (Topic 2)

Refer to the exhibit.

All devices attached to the network are shown. How many collision domains are present in this network?

A. 2

B. 3

C. 6

D. 9

E. 15

Answer: E

Explanation:

A switch uses a separate collision domain for each port so there are a total of 9 for each device shown. In addition to this, the switch to switch connections (3) are a separate collision domain. Finally, we add the switch to router connections (2) and the router to router connection (1) for a total of 15.

Q5. - (Topic 1)

Which two statements describe the operation of the CSMA/CD access method? (Choose two.)

A. In a CSMA/CD collision domain, multiple stations can successfully transmit data simultaneously.

B. In a CSMA/CD collision domain, stations must wait until the media is not in use before transmitting.

C. The use of hubs to enlarge the size of collision domains is one way to improve the operation of the CSMA/CD access method.

D. After a collision, the station that detected the collision has first priority to resend the lost data.

E. After a collision, all stations run a random backoff algorithm. When the backoff delay period has expired, all stations have equal priority to transmit data.

F. After a collision, all stations involved run an identical backoff algorithm and then synchronize with each other prior to transmitting data.

Answer: B,E

Explanation:

Ethernet networking uses Carrier Sense Multiple Access with Collision Detect (CSMA/CD), a protocol that helps devices share the bandwidth evenly without having two devices transmit at the same time on the network medium. CSMA/CD was created to overcome the problem of those collisions that occur when packets are transmitted simultaneously from different nodes. And trust me, good collision management is crucial, because when a node transmits in a CSMA/CD network, all the other nodes on the network receive and examine that transmission. Only bridges and routers can effectively prevent a transmission from propagating throughout the entire network! So, how does the CSMA/CD protocol work? Like this: when a host wants to transmit over the network, it first checks for the presence of a digital signal on the wire. If all is clear (no other host is transmitting), the host will then proceed with its transmission. But it doesn’t stop there. The transmitting host constantly monitors the wire to make sure no other hosts begin transmitting. If the host detects another signal on the wire, it sends out an extended jam signal that causes all nodes on the segment to stop sending data (think, busy signal). The nodes respond to that jam signal by waiting a while before attempting to transmit again. Backoff algorithms determine when the colliding stations can retransmit. If collisions keep occurring after 15 tries, the nodes attempting to transmit will then time out.

Q6. - (Topic 3)

ROUTER# show ip route

192.168.12.0/24 is variably subnetted, 9 subnets, 3 masks C 192.168.12.64 /28 is directly connected, Loopback1 C 192.168.12.32 /28 is directly connected, Ethernet0 C 192.168.12.48 /28 is directly connected, Loopback0 O 192.168.12.236 /30 [110/128] via 192.168.12.233, 00:35:36, Serial0 C 192.168.12.232 /30 is directly connected, Serial0 O 192.168.12.245 /30 [110/782] via 192.168.12.233, 00:35:36, Serial0 O 192.168.12.240 /30 [110/128] via 192.168.12.233, 00:35:36, Serial0 O 192.168.12.253 /30 [110/782] via 192.168.12.233, 00:35:37, Serial0 O 192.168.12.249 /30 [110/782] via 192.168.12.233, 00:35:37, Serial0 O 192.168.12.240/30 [110/128] via 192.168.12.233, 00:35:36, Serial 0

To what does the 128 refer to in the router output above?

A. OSPF cost

B. OSPF priority

C. OSPF hop count

D. OSPF ID number

E. OSPF administrative distance

Answer: A

Explanation:

The first parameter is the Administrative Distance of OSPF (110) while the second parameter is the cost of OSPF.

Q7. - (Topic 1)

Refer to the exhibit.

The output is from a router in a large enterprise. From the output, determine the role of the router.

A. A Core router.

B. The HQ Internet gateway router.

C. The WAN router at the central site.

D. Remote stub router at a remote site.

Answer: D

Explanation:

Since the routing table shows only a single default route using the single interface serial 0/0, we know that this is most likely a remote stub site with a single connection to the rest of the network. All the other answer options would mean that this router would have more connections, and would contain more routes.

Q8. - (Topic 3)

Refer to the exhibit.

The internetwork is using subnets of the address 192.168.1.0 with a subnet mask of

255.255.255.224. The routing protocol in use is RIP version 1. Which address could be assigned to the FastEthernet interface on RouterA?

A. 192.168.1.31

B. 192.168.1.64

C. 192.168.1.127

D. 192.168.1.190

E. 192.168.1.192

Answer: D

Explanation:

Subnet mask 255.255.255.224 with CIDR of /27 which results in 32 hosts per.

192.168.1.31 is the broadcast address for sunbet '0'

192.168.1.64 is the network address for subnet '2'

192.168.1.127 is the broadcast address for subnet '3'

192.168.1.192 is the network address for subnet '6'

Q9. - (Topic 5)

Why would a network administrator configure port security on a switch?

A. to prevent unauthorized Telnet access to a switch port

B. to prevent unauthorized hosts from accessing the LAN

C. to limit the number of Layer 2 broadcasts on a particular switch port

D. block unauthorized access to the switch management interfaces

Answer: B

Explanation:

You can use the port security feature to restrict input to an interface by limiting and identifying MAC addresses of the stations allowed to access the port. When you assign secure MAC addresses to a secure port, the port does not forward packets with source addresses outside the group of defined addresses. If you limit the number of secure MAC addresses to one and assign a single secure MAC address, the workstation attached to that port is assured the full bandwidth of the port. If a port is configured as a secure port and the maximum number of secure MAC addresses is reached, when the MAC address of a station attempting to access the port is different from any of the identified secure MAC addresses, a security violation occurs. Also, if a station with a secure MAC address configured or learned on one secure port attempts to access another secure port, a violation is flagged.

Q10. - (Topic 1)

Refer to the exhibit.

Mary is sending an instant message to Robert. The message will be broken into a series of packets that will traverse all network devices. What addresses will populate these packets as they are forwarded from Router1 to Router2?

A. Option A

B. Option B

C. Option C

D. Option D

E. Option E

Answer: B

Explanation:

The Source and Destination IP address is not going to change. Host 1 IP address will stay

as being the source IP and the Host 2 IP address will stay the destination IP address.

Those two are not going to change.

For the MAC address it is going to change each time it goes from one hope to another.

(Except switches... they don't change anything)

Frame leaving HOST 1 is going to have a source MAC of Host 1 and a destination MAC of

Router 1.

Router 1 is going to strip that info off and then will make the source MAC address of Router1's exiting interface, and making Router2's interface as the destination MAC address. Then the same will happen... Router2 is going to change the source/destination info to the source MAC being the Router2 interface that it is going out, and the destination will be Host2's MAC address.