Ccna certification Practice Tests

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Appendix 

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  Answers to Practice Test Questions

 89.  B.  Hubs do not participate in IEEE negotiation, and therefore the speed will be detected. 

However, since duplex cannot be negotiated, 10 Mb/s and 100 Mb/s connections will be 

half-duplex and 1000 Mb/s connections will be full-duplex. Therefore the switch interface 

will be set to 100 Mb/s half-duplex.

 90. C. The 

show interfaces status command will display the port number, description, 

connected status, VLAN, duplex, speed, and type of interface. The command 

show run is 

incorrect. The command 

show interfaces counters is incorrect. The command show 

counters interfaces is incorrect.

 91.  A.  The Transport layer is responsible for flow control via the TCP/IP protocols of TCP 

and UDP. The Network layer is responsible for logical addressing of network nodes. The 

Data Link layer is responsible for the framing of data and the physical addressing of local 

nodes. The Session layer is responsible for the setup of the dialog between two hosts.

 92.  C.  User Datagram Protocol (UDP) does not guarantee segments are delivered. Therefore, 

the programmer must account for segments that are never received or out of order. Sockets 

Layer (SSL) is a protocol used to encrypt a network transmission. Transmission allows  

for the network to automatically deal with lost segments because TCP guarantees 

segments are delivered. Network management station (NMS) is a term used with Simple 

Network Management Protocol (SNMP) to describe the collecting host for SNMP 

messages.

 93.  D.  TCP is a connection-based protocol via the three-way handshake. It is not faster than 

UDP. However, it allows for the retransmission of lost segments because of sequences and 

acknowledgments. TCP does not allow or account for error correction, only the detection 

of errors and lost or missing segments.

 94.  A.  The sender allocates a port dynamically above 1024 and associates it with the request 

through a process called a handle. This way, if a web browser creates three requests for 

three different web pages, the pages are loaded to their respective windows. The receiver 

will respond back to the requesting port dynamically allocated to the request (over 1024); 

these ports are also known as ephemeral ports. Dynamic allocation is always over 1024, 

not below 1024, and it is always the responsibility of the sender, not the receiver.

 95.  D.  The Simple Mail Transfer Protocol (SMTP) uses TCP port 25 to send mail. The Trivial 

File Transfer Protocol (TFTP) uses UDP/69 for communications. The Dynamic Host 

Configuration Protocol (DHCP) uses UDP/68 for communications. The Domain Name 

protocol uses UDP/53 for communications.

 96.  D.  TCP guarantees delivery of segments with sequence and acknowledgment numbers. 

At the Transport layer, each segment is given a sequence number that is acknowledged by 

the receiver. The source and destination ports are used for the delivery of segments, but 

they do not guarantee delivery. TCP checksums are used to detect errors in segments but 

do not guarantee delivery. Window size is used to adjust buffer size on the sending and 

receiving hosts.

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Chapter 1: Network Fundamentals (Domain 1)