わくわくIT資格勉強記

Which of the following is not a transport layer protocol?
　A. TP4
　B. TCP
　C. RTP
　D. UDP

TP4: OSI highest level of service Transport protocol

TP0: OSI lowest level of service Transport protocol

Which of the following statements about transport layer protocols is false?
　A. Most Internet applications use a transport layer protocol.
　B. Transport layer protocols can provide both reliable and unreliable services.
　C. Transport layer protocols provide end-to-end services for applications.
　D. Transport layer protocols require that additional software be added to your operating system.

Which of the following is not a characteristic of the TCP protocol?
　A. Reliable data transfer
　B. Connectionless operation
　C. Flow control supported
　D. Full-duplex operation

Which of the following is not a characteristic of the UDP protocol?
　A. Reliable data transfer
　B. Connectionless operation
　C. No flow control
　D. Appropriate for real-time traffic

Which of the following TCP flags is not matched with the correct definition?
　A. SYN -- Indicates the start of a TCP connection.
　B. ACK -- Acknowledges that a TCP segment has been received.
　C. FIN -- Indicates the closing of a TCP session.
　D. RST -- Re-sets the sequence number for a TCP session.

PSH: 1=バッファせずに直ちに上位アプリケーションにデータを渡す。Telnetなど

A TCP sequence or acknowledgment number consists of bits.
　A. 30
　B. 64
　C. 24
　D. 32

After a client initiates a connection request to a server with the SYN bit set, the server usually responds with a packet that has the bit set.
　A. SYN
　B. ACK
　C. SYN and ACK
　D. SYN, ACK, and URG

Which of the following TCP bits is set to indicate that an application wishes to close an open connection?
　A. RST
　B. FIN
　C. URG
　D. ACK

When operating in slow start mode, which of the following describes the mechanisms to throttle the amount of data sent?
　A. The receiver's advertised window size
　B. The sender's congestion window and the sender's advertised window size
　C. The sender's congestion window and the receiver's advertised window size
　D. The maximum segment size and the URG pointer

Which of the following are possible mechanisms by which a TCP sending process could recognize that packets it sent to a receiver had been dropped by the network?
　A. An RSND bit from the receiving TCP process
　B. Duplicate ACK numbers
　C. An advertised window size of 0
　D. An ICMP source quench message

Given the values MSS=1000 bytes, cwnd value=6, window size=5000, and sender's SN=5000, what will be the ACK number from the receiving station after the sender sends its next set of segments to the receiving station?
　A. 6000
　B. 11001
　C. 11000
　D. 10000

Which of the following types of applications would be least likely to use the UDP protocol?
　A. A "request-response" application
　B. An application that is sensitive to packet loss
　C. An application that is sensitive to delay
　D. A real-time application

DNS, RPC, RTP, SNMP, DHCP etc

TCP provide many advanced features missing from UDP.
Which of the following is an advantage that UDP has over TCP?
　A. It provides reliable data transfer.
　B. It can recover gracefully from packet loss.
　C. It reacts to network congestion.
　D. It adds little overhead to the data transfer.

Which of the following is least likely to be used as an ephemeral port?
　A. 1025
　B. 53212
　C. 1487
　D. 65938

DNS is a unique protocol in terms of its transport selection because simple name lookups use UDP, while "zone transfers" that transfer a large amount of name resolution information from one DNS server to another use TCP.
What is the least likely reason for using this approach?
　A. Name lookups are simple request-response.
　B. TCP is a reliable protocol.
　C. An unreliable zone transfer could result in serious name resolution discrepancies in network.
　D. UDP cannot be used for bulk file transfers.