CISCO CCNA Exam – Q153

Refer to the exhibit.
CISCO CCNA Exam – Q153

If the router Cisco returns the given output and has not had its router ID set manually, what value will OSPF use as its router ID?

A. 192.168.1.1
B. 172.16.1.1
C. 1.1.1.1
D. 2.2.2.2

Correct Answer: D

Explanation:
If a router-id is not configured manually in the OSPF routing process the router will automatically configure a router-id determined from the highest IP address of a logical interface (loopback interface) or the highest IP address of an active interface. If more than one loopback interfaces are configured, the router will compare the IP addresses of each of the interfaces and choose the highest IP address from the loopbacks.

CISCO CCNA Exam – Q152

What OSPF command, when configured, will include all interfaces into area 0?

A. network 0.0.0.0 255.255.255.255 area 0
B. network 0.0.0.0 0.0.0.0 area 0
C. network 255.255.255.255 0.0.0.0 area 0
D. network all-interfaces area 0

Correct Answer: A

Explanation:
Example 3-1 displays OSPF with a process ID of 1 and places all interfaces configured with an IP address in area 0. The network command network 0.0.0.0 255.255.255.255 area 0 dictates that you do not care (255.255.255.255) what the IP address is, but if an IP address is enabled on any interface, place it in area 0.

CISCO CCNA Exam – Q151

Which statement describes the process ID that is used to run OSPF on a router?

A. It is globally significant and is used to represent the AS number.
B. It is locally significant and is used to identify an instance of the OSPF database.
C. It is globally significant and is used to identify OSPF stub areas.
D. It is locally significant and must be the same throughout an area.

Correct Answer: B

Explanation:
The Process ID for OSPF on a router is only locally significant and you can use the same number on each router, or each router can have a different number-it just doesn’t matter. The numbers you can use are from 1 to 65,535. Don’t get this confused with area numbers, which can be from 0 to 4.2 billion.

CISCO CCNA Exam – Q150

Refer to the exhibit.
CISCO CCNA Exam – Q150

All of the routers in the network are configured with the ip subnet-zero command. Which network addresses should be used for Link A and Network A? (Choose two.)
A. Network A – 172.16.3.48/26
B. Network A – 172.16.3.128/25
C. Network A – 172.16.3.192/26
D. Link A – 172.16.3.0/30
E. Link A – 172.16.3.40/30
F. Link A – 172.16.3.112/30

Correct Answers: B, D

Explanation:
Only a /30 is needed for the point to point link and sine the use of the ip subnet-zero was used, 172.16.3.0/30 is valid. Also, a /25 is required for 120 hosts and again 172.16.3.128/25 is the best, valid option.

CISCO CCNA Exam – Q149

The network administrator needs to address seven LANs. RIP version 1 is the only routing protocol in use on the network and subnet 0 is not being used. What is the maximum number of usable IP addresses that can be supported on each LAN if the organization is using one class C address block?

A. 8
B. 6
C. 30
D. 32
E. 14
F. 16

Correct Answer: C

Explanation:
Since there is one class C network that means 256 total IP addresses. Since we need 7 LAN blocks and we cannot use the first one (subnet 0) we take 256/8=32 hosts.
However, since we need to reserve the network and broadcast addresses for each of these subnets, only 30 total IP addresses are usable.

CISCO CCNA Exam – Q148

What will happen if a private IP address is assigned to a public interface connected to an ISP?

A. Addresses in a private range will not be routed on the Internet backbone.
B. Only the ISP router will have the capability to access the public network.
C. The NAT process will be used to translate this address to a valid IP address.
D. A conflict of IP addresses happens, because other public routers can use the same range.

Correct Answer: A

Explanation:
Private RFC 1918 IP addresses are meant to be used by organizations locally within their own network only, and cannot be used globally for Internet use.

CISCO CCNA Exam – Q147

Which two benefits are provided by using a hierarchical addressing network addressing scheme? (Choose two.)

A. reduces routing table entries
B. auto-negotiation of media rates
C. efficient utilization of MAC addresses
D. dedicated communications between devices
E. ease of management and troubleshooting

Correct Answers: A,E

Explanation:
Here are some of the benefits of hierarchical addressing:

Reduced number of routing table entries — whether it is with your Internet routers or your internal routers, you should try to keep your routing tables as small as possible by using route summarization. Route summarization is a way of having a single IP address represent a collection of IP addresses; this is most easily accomplished when you employ a hierarchical addressing plan. By summarizing routes, you can keep your routing table entries (on the routers that receive the summarized routes) manageable, which offers the following benefits:

  • More efficient routing
  • A reduced number of CPU cycles when recalculating a routing table or sorting through the routing table entries to find a match
  • Reduced router memory requirements
  • Reduced bandwidth required to send the fewer, smaller routing updates
  • Faster convergence after a change in the network
  • Easier troubleshooting
  • Increased network stability

Efficient allocation of addresses — Hierarchical addressing lets you take advantage of all possible addresses because you group them contiguously.

CISCO CCNA Exam – Q146

What is the alternative notation for the IPv6 address B514:82C3:0000:0000:0029:EC7A:0000:EC72?

A. B514 : 82C3 : 0029 : EC7A : EC72
B. B514 : 82C3 :: 0029 : EC7A : EC72
C. B514 : 82C3 : 0029 :: EC7A : 0000 : EC72
D. B514 : 82C3 :: 0029 : EC7A : 0 : EC72

Correct Answer: D

Explanation:
There are two ways that an IPv6 address can be additionally compressed: compressing leading zeros and substituting a group of consecutive zeros with a single double colon (::). Both of these can be used in any number of combinations to notate the same address. It is important to note that the double colon (::) can only be used once within a single IPv6 address notation. So, the extra 0’s can only be compressed once.

CISCO CCNA Exam – Q145

Refer to the diagram.

All hosts have connectivity with one another. Which statements describe the addressing scheme that is in use in the network? (Choose three.)

A. The subnet mask in use is 255.255.255.192.
B. The subnet mask in use is 255.255.255.128.
C. The IP address 172.16.1.25 can be assigned to hosts in VLAN1
D. The IP address 172.16.1.205 can be assigned to hosts in VLAN1
E. The LAN interface of the router is configured with one IP address.
F. The LAN interface of the router is configured with multiple IP addresses.

Correct Answers: B,C,F

Explanation:
The subnet mask in use is 255.255.255.128: This is subnet mask will support up to 126 hosts, which is needed.
The IP address 172.16.1.25 can be assigned to hosts in VLAN1: The usable host range in this subnet is 172.16.1.1-172.16.1.126
The LAN interface of the router is configured with multiple IP addresses: The router will need 2 subinterfaces for the single physical interface, one with an IP address that belongs in each VLAN.

CISCO CCNA Exam – Q144

Which two statements describe characteristics of IPv6 unicast addressing? (Choose two.)

A. Global addresses start with 2000::/3.
B. Link-local addresses start with FE00:/12.
C. Link-local addresses start with FF00::/10.
D. There is only one loopback address and it is ::1.
E. If a global address is assigned to an interface, then that is the only allowable address for the interface.

Correct Answers: A, D

Explanation:
Below is the list of common kinds of IPv6 addresses:
CISCO CCNA Exam – Q144