CCNA Chapter 7-11 Exam Review

计算机网络 CCNA

创建时间:2019-01-20 06:59

字数:1.1k 阅读:

📚📚 设计可变长子网Designing VLSM addressing scheme
📚📚 实际就是按需分配子网，根据所需主机数量来分配

An IPv4 address is divided into two parts: a network portion – to identify the specific network on which a host resides, and a host portion – to identify specific hosts on a network. A subnet mask is used to identify the length of each portion.

What are three characteristics of multicast transmission?

A single packet can be sent to a group of hosts.
Multicast transmission can be used by routers to exchange routing information.
The range of 224.0.0.0 to 224.0.0.255 is reserved to reach multicast groups on a local network.

Explanation:The private IP addresses are within these three ranges:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255

Which three IP addresses are private ? (Choose three.)

The private IP addresses are within these three ranges:
10.0.0.0 – 10.255.255.255
172.16.0.0 – 172.31.255.255
192.168.0.0 – 192.168.255.255
Which two IPv4 to IPv6 transition techniques manage the interconnection of IPv6 domains? (Choose two.)

dual stack
Network Address Translation 64 (NAT64)
tunneling

Explanation:There are three techniques to allow IPv4 and IPv6 to co-exist on a network. Dual stack allows IPv4 and IPv6 to coexist on the same network segment. Dual stack devices run both IPv4 and IPv6 protocol stacks simultaneously. Tunneling is a method of transporting an IPv6 packet over an IPv4 network. The IPv6 packet is encapsulated inside an IPv4 packet, similar to other types of data. Network Address Translation 64 (NAT64) allows IPv6-enabled devices to communicate with IPv4-enabled devices using a translation technique similar to NAT for IPv4.

What type of address is automatically assigned to an interface when IPv6 is enabled on that interface?

link-local

Explanation:When IPv6 is enabled on any interface, that interface will automatically generate an IPv6 link-local address.

What are two types of IPv6 unicast addresses? (Choose two.)

loopback
link-local

Explanation:Multicast, anycast, and unicast are types of IPv6 addresses. There is no broadcast address in IPv6. Loopback and link-local are specific types of unicast addresses

What are three parts of an IPv6 global unicast address? (Choose three.)

an interface ID that is used to identify the local host on the network
a global routing prefix that is used to identify the network portion of the address that has been provided by an ISP
a subnet ID that is used to identify networks inside of the local enterprise site

An administrator wants to configure hosts to automatically assign IPv6 addresses to themselves by the use of Router Advertisement messages, but also to obtain the DNS server address from a DHCPv6 server. Which address assignment method should be configured?

stateless DHCPv6

Explanation:Stateless DHCPv6 allows clients to use ICMPv6 Router Advertisement (RA) messages to automatically assign IPv6 addresses to themselves, but then allows these clients to contact a DHCPv6 server to obtain additional information such as the domain name and address of DNS servers. SLAAC does not allow the client to obtain additional information through DHCPv6, and stateful DHCPv6 requires that the client receive its interface address directly from a DHCPv6 server. RA messages, when combined with an EUI-64 interface identifier, are used to automatically create an interface IPv6 address, and are part of both SLAAC and stateless DHCPv6.

Which protocol supports Stateless Address Autoconfiguration (SLAAC) for dynamic assignment of IPv6 addresses to a host?

ICMPv6

What is the purpose of ICMP messages?

to provide feedback of IP packet transmissions

What is indicated by a successful ping to the ::1 IPv6 address?

IP is properly installed on the host.

Explanation：The IPv6 address ::1 is the loopback address. A successful ping to this address means that the TCP/IP stack is correctly installed. It does not mean that any addresses are correctly configured.

What field content is used by ICMPv6 to determine that a packet has expired?

Hop Limit field

Explanation:ICMPv6 sends a Time Exceeded message if the router cannot forward an IPv6 packet because the packet expired. The router uses a hop limit field to determine if the packet has expired, and does not have a TTL field.

Match each description with an appropriate IP address.

Link-Local addresses are assigned automatically by the OS environment and are located in the block 169.254.0.0/16.
The private addresses ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16.
TEST-NET addresses belong to the range 192.0.2.0/24.
Experimental addresses are reserved in the block 240.0.0.0 to 255.255.255.254.
Loopback addresses belong to the block 127.0.0.0/8.

What is a result of connecting two or more switches together?

The size of the broadcast domain is increased.

If a network device has a mask of /28, how many IP addresses are available for hosts on this network?
- 14
  Explanation:A /28 mask is the same as 255.255.255.240. This leaves 4 host bits(32-28=4 host bits). With 4 host bits, 16 IP addresses are possible, but one address represents the subnet number and one address represents the broadcast address. 14 addresses can then be used to assign to network devices. $2^4-2=16$

How many host addresses are available on the network 172.16.128.0 with a subnet mask of 255.255.252.0?
- 1022
  Explanation:
  A mask of 255.255.252.0 is equal to a prefix of /22. A /22 prefix provides 22 bits for the network portion and leaves 10 bits for the host portion. The 10 bits in the host portion will provide 1022 usable IP addresses (210 – 2 = 1022).
![](/Users/junyi/jooeys.github.io/source/pics/subnetting example2.png)

16.

转载请注明来源，欢迎对文章中的引用来源进行考证，欢迎指出任何有错误或不够清晰的表达。可以在下面评论区评论，也可以邮件至 jyzh@yahoo.com