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]
