Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 74.  C.  Cat5e can support up to 1 Gb/s via the 1000Base-T specification. Since 10Base-T, 

100Base-T, and 1000Base-T can be run up to 100 meters in length, it allows for 

interchangeability with speeds. It was very common when Cat5e came out 20 years ago 

for installers to future-proof wiring installations with it. 10 Gb/s requires Category 6 or 

6a cable to operate at speeds of 10 Gb/s. All other answers are incorrect.

 75.  D.  Crossover cables are wired with the 568B specification on one side, and on the other 

side, the 568A specification is used. This change in wiring delivers the TX pair on pins 3 

and 6 to the RX pair on pins 1 and 2. Straight-through cables are wired with the 568B 

specification on both sides.

 76.  C.  The exhibit shows an example of a debug of outgoing packets, and therefore, the 

configuration problem is on this router. This router’s username must match the adjacent 

router’s hostname and both passwords must match. PAP is already configured on this 

router, as seen in the exhibit. PPP is also already configured on this router, as seen in the 

exhibit. This local router will not verify the remote username matches on the adjacent 

router; the adjacent router will verify when this router transmits its locally configured 

username and password.

 77.  B.  The provider edge (PE) router is responsible for adding the MPLS label to a packet. 

The customer edge (CE) router is passed the MPLS packet with the label stripped off. The 

customer premise switch is the customer’s local switching device and has no relation to 

MPLS. The term label switch router (LSR) is used to describe the internal switching of 

the MPLS network.

 78.  D.  The demarc, or demarcation point, is the end of the provider’s responsibility for the 

connection and the point where the customer’s responsibility begins. This point is often a 

physical location where the provider can test their connection and hand off the service to 

the customer. Customer premises equipment (CPE) is the router or ancillary equipment used 

to facilitate the connection to the wide area network (WAN). The central office (CO) is a 

physical location where all of the customer connections on the local loop meet up and WAN 

services are delivered. The CO is also sometimes referred to as the point of presence (POP).

 79.  C.  The speed of a DS1 connection is 1.544 Mb/s; it is also referred to as a T1 connection. 

The speed of a European DS1 called an E1 is 2.048 Mb/s. The speed of DS3 line is 44.736 

Mb/s, and this line is also referred to as a T3. The speed of an optical carrier (OC-12) 

WAN connection is 622.08 Mb/s.

 80.  C.  When you’re checking for speed and/or duplex issues, the 

show interface status 

command will detail all of the ports with their negotiated speed and duplex.  

The command 

show speed is incorrect. The command show duplex is incorrect. The 

command 

show diagnostics is incorrect.

 81.  C.  Although cabling could create an issue similar to this, it would not disable the interface. 

The most probable cause is that there is a duplex mismatch since there are a large number 

of late collisions. The most probable scenario is that the far end is set to half-duplex and 

the interface is set to full-duplex, or the opposite might also be true. The interface is not 

shut down because the exhibit would state that the interface was administratively disabled. 

There is no evidence in the exhibit that the interface has negotiated at half-duplex. The 

exhibit also shows no evidence that the cable is shorted on the interface.

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Chapter 1: Network Fundamentals (Domain 1)