Chapter 8 TCP/IP Internetworking I

18) For 100,000 addresses, which will have fewer rows? A) a routing table B) an Ethernet switching table C) Both will be about the same length.

Answer: A

2) When a router forwards incoming packets closer to their destination hosts, this is ________. A) routing B) switching C) bridging D) relaying

Answer: A

21) In a routing table, Rows 47 and 3497 both match the destination IP address of an arriving packet's IP address. Which row will the router look at first when trying to find matches? A) 1 B) 47 C) 3497 D) the default row

Answer: A

23) Row 2707 has the mask /16 and the cost metric 20. Row 4400 has the mask /14 and the cost metric 10. Which row will the router choose if both are matches? A) 2707 B) 4400 C) either A or B D) The router will choose the default row.

Answer: A

24) Row 2707 has the mask /16 and the reliability metric 20. Row 4400 has the mask /16 and the reliability metric 10. Which row will the router choose if both are matches? A) 2707 B) 4400 C) either A or B D) The router will choose the default row

Answer: A

28) According to the IETF standards, if a router receives a series of packets from the same IP address to the same IP address, it should ________. A) go through the entire process for each packet B) cache the decision made for the first packet and use this decision on subsequent packets C) skip the first step in the routing process but go through other steps for each subsequent packet D) none of the above

Answer: A

29) Compared to normal routing, decision caching is ________. A) faster B) less dangerous C) both A and B

Answer: A

3) Which of the following is one of the three parts of an IPv4 address? A) subnet part B) mask C) both A and B D) neither A nor B

Answer: A

31) What does a router do with Address Resolution Protocol request messages? A) It broadcasts them. B) It sends them directly to the destination host. C) It sends them to a next-hop router. D) It sends them to the default next-hop router.

Answer: A

46) How many fields are there in an IPv6 address written for human reading? A) 8 B) 16 C) 32 D) 128

Answer: A

47) If I simplify the address 2001:0000:0000:00fe:0000:0000:0000:cdef, I get ________. A) 2001:::fe::::cdef B) 2001::fe::::cdef C) 2001:::fe::cdef D) 2001::00fe:::cdef

Answer: A

48) If I simplify the address 2001:0ed2:056b:00d3:000c:abcd:0bcd:0fe0, I get ________. A) 2001:ed2:56b:d3:c:abcd:bcd:fe0 B) 2001:ed2:56b:d3:c:abcd:bcd:fe C) either A or B D) neither A nor B

Answer: A

52) Which of the following allows routers to check for errors in the header when a packet arrives? A) IPv4 B) IPv6 C) both A and B D) neither A nor B

Answer: A

56) If someone says that a 1-bit flag is not set, this means that its value is ________. A) 0 B) 1 C) blank D) We cannot say.

Answer: A

57) A TCP ________ segment is a request to close a connection. A) FIN B) ACK C) Close D) Disconnect

Answer: A

58) Four-way closes use ________ segments. A) FIN B) RST C) either A or B D) neither A nor B

Answer: A

61) Which of the following can handle an application message that is one megabyte in size? A) TCP B) UDP C) both A and B D) neither A nor B

Answer: A

7) An internal router only connects different IP ________. A) subnets B) networks C) both A and B D) neither A nor B

Answer: A

9) In a network mask, the 1s correspond to the ________. A) network part B) subnet part C) host part D) none of the above

Answer: A

15) For a given volume of traffic, which are more expensive? A) switches B) routers C) Both of the above are about equally expensive.

Answer: B

16) Routers usually are connected in a ________ topology. A) point-to-point B) mesh C) hierarchical D) bus

Answer: B

17) There is a row for each individual Ethernet address in a(n) ________. A) Router table B) Ethernet switching table C) both A and B D) neither A nor B

Answer: B

19) A(n) ________ must find the best-matching row in its ________ table by comparing multiple row matches. A) Ethernet switch, switching B) router, routing C) both A and B D) neither A nor B

Answer: B

22) The first step in the routing process involves ________. A) selecting the best match row B) comparing the packet's destination IP address to all rows C) comparing the packet's destination IP address to matching rows D) selecting an interface

Answer: B

34) ARP operates at ________. A) Layer 2 B) Layer 3 C) both A and B D) neither A nor B

Answer: B

35) The main version of Internet Protocol in use today is IP version ________. A) 1 B) 4 C) 5 D) 6

Answer: B

37) A router will discard a packet if the Time to Live (TTL) value in an arriving packet is ________. A) 0 B) 1 C) 254 D) 256

Answer: B

43) For human reading, IPv6 address is written in ________ notation. A) decimal B) hexadecimal C) binary D) runic

Answer: B

49) If I simplify the address 2001:0000:0000:00fe:0000:0000:abcd:13ef, I get ________. A) 2001:::fe:::abcd:13ef B) 2001::fe:::abcd:13ef C) 2001:::fe::abcd:13ef D) 2001::fe::abcd:13ef

Answer: B

51) In IPv6, the payload length gives the number of octets in the ________. A) entire packet B) entire packet minus the main header C) entire packet minus the main and extension headers D) entire packet minus the extension headers

Answer: B

55) One-bit fields are called ________ fields. A) SYN B) flag C) ACK D) none of the above

Answer: B

59) An abrupt close uses a(n) ________ segment. A) FIN B) RST C) either A or B D) neither A nor B

Answer: B

60) Which of the following segments is not acknowledged? A) FIN B) RST C) Both of the above are acknowledged. D) Neither A nor B is acknowledged.

Answer: B

1) Router connectors are called ________. A) sockets B) plugs C) interfaces D) ports

Answer: C

11) In the mask 255.255.255.0, how many 1s are there? A) 8 B) 16 C) 24 D) We cannot say.

Answer: C

13) Express the mask /24 in dotted decimal notation. A) 255.0.0.0 B) 255.255.0.0 C) 255.255.255.0 D) none of the above

Answer: C

20) The default row ________. A) always has the mask /32 B) will always match the destination IP address of an incoming packet C) both A and B D) neither A nor B

Answer: C

25) Deciding what interface and to what device to send the packet back out is step ________ in the routing process. A) 1 B) 2 C) 3 D) 4

Answer: C

26) After selecting a row on a routing table, a router will send packets out to the ________. A) port B) socket C) interface D) plug

Answer: C

30) To deliver an arriving packet to a destination host on a subnet connected to a router, the router needs to know the destination host's ________ before the router can send the packet on to the destination host. A) IP address B) data link layer address C) both A and B D) neither A nor B

Answer: C

33) Address Resolution Protocol is used to find the destination data link layer destination addresses of ________. A) destination hosts B) routers C) both A and B D) neither A nor B

Answer: C

40) The new version of Internet Protocol that is coming into use is IP version ________. A) 1 B) 2 C) 6 D) 8

Answer: C

44) For human reading, symbols in IPv6 addresses are written in fields of ________ symbols. A) 1 B) 2 C) 4 D) 16

Answer: C

45) For human reading, IPv6 fields are separated by ________. A) dashes B) slashes C) colons D) none of the above

Answer: C

5) The total length of an IPv4 address is ________ bits. A) 8 B) 16 C) 32 D) We cannot say.

Answer: C

53) The encapsulating security protocol offers ________. A) confidentiality B) authentication C) both A and B D) neither A nor B

Answer: C

54) TCP messages are called ________. A) frames B) packets C) segments D) fragments

Answer: C

8) A mask has ________ bits. A) 8 B) 16 C) 32 D) We cannot say.

Answer: C

10) In a subnet mask, the 1s correspond to the ________. A) network part B) subnet part C) host part D) none of the above

Answer: D

12) In the mask /14, how many 1s are there? A) 8 B) 16 C) 24 D) none of the above

Answer: D

14) Express the mask /18 in dotted decimal notation. A) 255.0.0.0 B) 255.255.0.0 C) 255.255.255.0 D) none of the above

Answer: D

27) The router selects a row in which the next-hop router is labeled local. The router will send the packet to the ________. A) default router B) local next-hop router C) local host D) destination host

Answer: D

32) A router must use the Address Resolution Protocol process ________. A) when a new router comes online B) when a router goes offline C) whenever it forwards an IP packet D) whenever it forwards an IP packet to a host that is not in its ARP cache

Answer: D

36) Which IPv4 header field is used to specify quality of service? A) type of service B) version number C) ECN D) differentiated services control point

Answer: D

38) In an IPv4 packet, the ________ field value tells the type of message contained in the IP packet's data field. A) data B) next-hop C) next-header D) protocol

Answer: D

39) Which is a problem with IPv4 addresses? A) They cannot be used on wireless devices. B) They are too complex. C) Routers find it difficult to handle them. D) We have run out of them.

Answer: D

4) The network part of an IPv4 address is ________ bits long. A) 8 B) 16 C) 32 D) It is hard to say with limited information.

Answer: D

41) The main benefit of IPv6 over IPv4 is ________. A) two more bits in the IP address B) two more bytes in the IP address C) the ability to have quality-of-service guarantees D) the ability to support more possible hosts

Answer: D

42) What is pushing IPv6 adoption now? A) pressure from ISPs B) pressure from the IETF C) pressure from ISO D) none of the above

Answer: D

50) The version number field in IPv6 has the value ________. A) 0001 B) 0100 C) 0101 D) 0110

Answer: D

6) In the IPv4 address 1.2.3.4, what is the network part? A) 1 B) 1.2 C) 1.2.3 D) It is hard to say with limited information.

Answer: D