a) Describe the simple message ordering in HTTP. [53] b) In HTTP, can the server transmit if it has not received a request message from the client? [53] c) Describe the three-step handshake in TCP connection openings. [53-55] d) What kind of message does the destination host send if it does not receive a segment during a TCP connection? [54-55] e) What kind of message does the destination host send if it receives a segment that has an error during a TCP connection? [54-55] f) Under what conditions will a source host TCP process retransmit a segment? [55] g) Describe the four-step handshake in TCP connection closes. [56] h) After a side initiates the close of a connection by sending a FIN segment, will it send any more segments? Explain. [56] i) In Figure 2-7, suppose Host A had already sent A6 before it realized that it would need to resend A5. When it then resent A5, A6 would arrive before A5. How would Host B be able to put the information in the two segments back in order? [55-56] 4. a) What are the three general parts of messages? [57-58] b) What does the data field contain? [58] c) What is the definition of a header? [58] d) Is there always a data field in a message? [58] e) What is the definition of a trailer? [58] f) Are trailers common? [58] g) Distinguish between headers and header fields. [58] h) Distinguish between octets and bytes. [58] 5. a) How long are Ethernet MAC addresses? [60] b) What devices read Ethernet destination MAC addresses? [59] c) If the receiver detects an error on the basis of the value in the Frame Check Sequence field, what does it do? [60] d) Ethernet does error detection but not error correction. Is Ethernet a reliable protocol? Explain. [60] 8. a) Why are sequence numbers good? [62] b) What are 1-bit fields called? [61] c) If someone says that a flag field is set, what does this mean? [61] d) If the ACK bit is set, what other field must have a value? [61, 63] e) What is the purpose of the acknowledgment number field? [61, 63] 9. a) What are the four fields in a UDP header? [43] b) Describe the third. [43] c) Describe the fourth. [43] d) Is UDP reliable? Explain. [43] 11. a) What is the syntax of a socket? [65] b) In Figure 2-13, when the client transmits to the webserver host, what is the source port number? [65] c) What is the destination port number? [65] d) What is the source socket? [65] e) What is the destination socket? [65] f) When the SMTP server transmits to the client host, what is the source port number? [65] g) What is the destination port number? [65] h) What is the source socket? [65] i) What is the destination socket? [65] 12. a) Is the application layer standard always HTTP? [65-66] b) Which layer has the most standards? [65] c) At which layer would you find standards for voice over IP? (The answer is not explicitly in this section.) [65-66] d) Are all application layer standards simple like HTTP? [67] e) In HTTP response headers, what is the syntax of most lines (which are header fields)? [67] f) In HTTP request and response message, how is the end of a field indicated? [67] g) Do HTTP request messages have headers, data fields, and trailers? h) Do HTTP response messages that deliver files have headers, data fields, and trailers? [67] 18. a) What is encapsulation? [72] b) Why is encapsulation necessary for there to be communication between processes operating at the same layer but on different hosts, routers, or switches? [72] c) After the internet layer process in Figure 2-19 receives the TCP segment from the transport layer process, what two things does it do? [72-73] d) After the data link layer process in Figure 2-19 receives the IP packet from the internet layer process, what two things does it do? [72-73] e) After the physical layer process receives a frame from the data link layer process, what does the physical layer process do? [72-73] f) If encapsulation occurs on the source host, what analogous process do you think will occur on the destination host? (The answer is not in the text.) [72-73] 19. a) What does a network standards architecture do? [75] c) What are the two dominant network standards architectures? [75] d) What is the dominant network standards architecture in most real firms today? [75] e) Are the two network standards architectures competitors? [75] 23. a) Which layers of the hybrid TCP/IP–OSI standards architecture use OSI standards? [80] b) Which layers use TCP/IP standards? [80] c) Do wireless LAN standards come from OSI or TCP/IP? Explain. (The answer is not explicitly in this section.) [80] d) Do switched WAN standards come from OSI or TCP/IP? Explain. (Again, the answer is not explicitly in this section.) [80] *24. a) At which layers do OSI standards dominate usage? [80] b) Name and describe the functions of OSI Layer 5. [82] c) Name and describe the intended use of OSI Layer 6. [81] d) How is the OSI presentation layer actually used? [81] e) Beginning with the physical layer (Layer 1), give the name and number of the OSI layers. [80-81]