178
Chapter 3
Internet Protocols
Answers to Review Questions
1.
C. Internet Control Message Protocol (ICMP) is used to send
redirects back to an originating router.
2.
E. First start by using the 256 mask, which in this case is 256
- 240 = 16.
The first subnet is 16; the second subnet is 32. This host must be in the
16 subnet; the broadcast address is 31, and the valid host range is 17
-30.
3.
D. A Class B network is defined in the first octet with the numbers
128191.
4.
A, C, D, E, G. UDP is connectionless, TCP is connection-oriented
and uses windowing, and ARP is used to find a hardware address from
a known IP address.
5.
B, E. 172.16.25.11 is a Class B address, and the host portion is 25.11.
6.
B. Address Resolution Protocol (ARP) is used to find the hardware
address from a known IP address.
7.
A, B. The Ping program uses ICMP echo request and echo replies to
check a host on an internetwork.
8.
C. A Class C network address only has 8 bits for defining hosts.
2
8
- 2 = 254.
9.
C. The two subnets provided by this Class B mask are 64 and 128.
The broadcast address for the 128 subnet is 191.
10.
B. First start with 256 mask or, in this case, 256
- 192 = 64. 64 is the
first subnet; 128 is the second subnet. This host is in the 64subnet
range, the broadcast address is 127.255, and the valid host range is
64.1127.254.
11.
C. Take a look at the answers and see which subnet mask will give you
what you need for subnetting. 252 gives you 62 subnets, 248 gives
you 30 subnets, 240 gives you 14 subnets, and 255 is invalid. Only the
third option (240) gives you what you need.
12.
B, D. ICMP is used by both Ping and Traceroute.
13.
C. MAC addresses are a flat address scheme and used by bridges/
switches to make forwarding/filtering decisions. Routers use IP
addresses, which is a hierarchical address scheme, to make routing
decisions.
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