Cisco 100-101 Exam Real Dumps Questions

100-101 Exam Question 26:


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 back off algorithm. When the back off delay period has expired, all stations have equal priority to transmit data.
F. After a collision, all stations involved run an identical back off algorithm and then synchronize with each other prior to transmitting data.


Correct Answer: BE
Explanation/Reference:
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.

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Question 25

A switch receives a frame on one of its ports. There is no entry in the MAC address table for the destination MAC address. What will the switch do with the frame?

A. drop the frame
B. forward it out of all ports except the one that received it
C. forward it out of all ports
D. store it until it learns the correct port

Correct Answer: B
Explanation:
Understanding this concept is prime for understanding that when switch receives the data frame from the host not having the MAC address already in the MAC table, it will add the MAC address to the source port on the MAC address table and sends the data frame. If the switch already has the MAC address in it's table for the destination, it will forward the frame directly to the destination port.If it was not already in it's MAC table, then they frame would have been flooded out all ports except for the port that it came from.

New Cisco 100-101 Exam Dumps Question

QUESTION 24

To what type of port would a cable with a DB-60 connector attach?

A. Serial port
B. Console port
C. Ethernet port
D. Fibre optic port

Correct Answer: A

Cisco 100-101 Exam Questions & Answers

QUESTION 23

Which two characteristics apply to Layer 2 switches? (Choose two.)

A. Increases the number of collision domains
B. Decreases the number of collision domains
C. Implements VLAN
D. Decreases the number of broadcast domains
E. Uses the IP address to make decisions for forwarding data packets

Correct Answer: AC
Explanation:
Layer 2 switches offer a number of benefits to hubs, such as the use of VLANs and each switch port is in its own separate collision domain, thus eliminating collisions on the segment.

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Question 22

What are two common TCP applications? (Choose two.)

A. TFTP
B. SMTP
C. SNMP
D. FTP
E. DNS

Correct Answer: B,D
Explanation:
SMTP uses TCP port 25, while FTP uses TCP ports 20 and 21. http://pentestlab.wordpress.com/2012/03/05/common-tcpip-ports/

Cisco 100-101 Exam Questions

Question 21
 Refer to the exhibit.

Host A is sending a packet to Host B for the first time. What destination MAC address will Host A use in the ARP request?

A. 192.168.0.1
B. 172.16.0.50
C. 00-17-94-61-18-b0
D. 00-19-d3-2d-c3-b2
E. ff-ff-ff-ff-ff-ff
F. 255.255.255.255

Correct Answer: E
Explanation/Reference:
http://www.technicalhowto.com/protocols/arp/arp.html
For the initial communication, Host A will send a broadcast ARP (all F's) to determine the correct address to use to reach the destination.
ARP sends an Ethernet frame called an ARP request to every host on the shared link-layer legmen. The Ethernet header includes the source host MAC address and a destination address of all Fs representing a broadcast frame. The ARP request contains the sender's MAC and IP address and the target (destination)IP address. The target's MAC address is set to all 0s.ARP Request

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100-101 Question 20

A workstation has just resolved a browser URL to the IP address of a server. What protocol will the workstation now use to determine the destination MAC address to be placed into frames directed toward the server?

A. HTTP
B. DNS
C. DHCP
D. RARP
E. ARP

Correct Answer: E
Explanation/Reference:The RARP protocol is used to translate hardware interface addresses to protocol addresses. The RARP message format is very similar to the ARP format. When the booting computer sends the broadcast ARP request, it places its own hardware address in both the sending and receiving fields in the encapsulated ARP data packet. The RARP server will fill in the correct sending and receiving IP addresses in its response to the message. This way the booting computer will know its IP address when it gets the message from the RARP server.