CISCO CCNA Exam – Q138

Refer to the exhibit.
CISCO CCNA Exam – Q138

In this VLSM addressing scheme, what summary address would be sent from router A?

A. 172.16.0.0 /16
B. 172.16.0.0 /20
C. 172.16.0.0 /24
D. 172.32.0.0 /16
E. 172.32.0.0 /17
F. 172.64.0.0 /16

Correct Answer: A

Explanation:
Router A receives 3 subnets: 172.16.64.0/18, 172.16.32.0/24 and 172.16.128.0/18.
All these 3 subnets have the same form of 172.16.x.x so our summarized subnet must be also in that form.
The smallest subnet mask of these 3 subnets is /18 so our summarized subnet must also have its subnet mask equal or smaller than /18.
Only answer A has these 2 conditions .

CISCO CCNA Exam – Q137

How is an EUI-64 format interface ID created from a 48-bit MAC address?

A. by appending 0xFF to the MAC address
B. by prefixing the MAC address with 0xFFEE
C. by prefixing the MAC address with 0xFF and appending 0xFF to it
D. by inserting 0xFFFE between the upper three bytes and the lower three bytes of the MAC address
E. by prefixing the MAC address with 0xF and inserting 0xF after each of its first three bytes

Correct Answer: D

Explanation:
The modified EUI-64 format interface identifier is derived from the 48-bit link-layer (MAC) address by inserting the hexadecimal number FFFE between the upper three bytes (OUI field) and the lower three bytes (serial number) of the link layer address.

CISCO CCNA Exam – Q136

Refer to the exhibit.
CISCO CCNA Exam – Q136

What is the most efficient summarization that R1 can use to advertise its networks to R2?

A.
172.1.0.0/22
B.
172.1.0.0/21
C.
172.1.4.0/22
D.
172.1.4.0/24
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24
E.
172.1.4.0/25
172.1.4.128/25
172.1.5.0/24
172.1.6.0/24
172.1.7.0/24

Correct Answer: C

Explanation:
The 172.1.4.0/22 subnet encompasses all routes from the IP range 172.1.4.0 – 172.1.7.255.

CISCO CCNA Exam – Q135

Which option is a valid IPv6 address?

A. 2001:0000:130F::099a::12a
B. 2002:7654:A1AD:61:81AF:CCC1
C. FEC0:ABCD:WXYZ:0067::2A4
D. 2004:1:25A4:886F::1

Correct Answer: D

Explanation:
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:). An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The leading 0’s in a group can be collapsed using ::, but this can only be done once in an IP address.

CISCO CCNA Exam – Q134

Which three are characteristics of an IPv6 anycast address? (Choose three.)

A. one-to-many communication model
B. one-to-nearest communication model
C. any-to-many communication model
D. a unique IPv6 address for each device in the group
E. the same address for multiple devices in the group
F. delivery of packets to the group interface that is closest to the sending device

Correct Answers: B, E, F

Explanation:
A new address type made specifically for IPv6 is called the Anycast Address. These IPv6 addresses are global addresses, these addresses can be assigned to more than one interface unlike an IPv6 unicast address. Anycast is designed to send a packet to the nearest interface that is a part of that anycast group.
The sender creates a packet and forwards the packet to the anycast address as the destination address which goes to the nearest router. The nearest router or interface is found by using the metric of a routing protocol currently running on the network. However in a LAN setting the nearest interface is found depending on the order the neighbors were learned. The anycast packet in a LAN setting forwards the packet to the neighbor it learned about first.

CISCO CCNA Exam – Q133

A national retail chain needs to design an IP addressing scheme to support a nationwide network. The company needs a minimum of 300 sub-networks and a maximum of 50 host addresses per subnet. Working with only one Class B address, which of the following subnet masks will support an appropriate addressing scheme? (Choose two.)

A. 255.255.255.0
B. 255.255.255.128
C. 255.255.252.0
D. 255.255.255.224
E. 255.255.255.192
F. 255.255.248.0

Correct Answers: B,E

Explanation:
Subnetting is used to break the network into smaller more efficient subnets to prevent excessive rates of Ethernet packet collision in a large network. Such subnets can be arranged hierarchically, with the organization’s network address space (see also Autonomous System) partitioned into a tree-like structure. Routers are used to manage traffic and constitute borders between subnets.
A routing prefix is the sequence of leading bits of an IP address that precede the portion of the address used as host identifier. In IPv4 networks, the routing prefix is often expressed as a “subnet mask”, which is a bit mask covering the number of bits used in the prefix. An IPv4 subnet mask is frequently expressed in quad-dotted decimal representation, e.g., 255.255.255.0 is the subnet mask for the 192.168.1.0 network with a 24-bit routing prefix (192.168.1.0/24).

CISCO CCNA Exam – Q132

Refer to the exhibit.
CISCO CCNA Exam – Q132

A network administrator is adding two new hosts to SwitchA. Which three values could be used for the configuration of these hosts? (Choose three.)

A. host A IP address: 192.168.1.79
B. host A IP address: 192.168.1.64
C. host A default gateway: 192.168.1.78
D. host B IP address: 192.168.1.128
E. host B default gateway: 192.168.1.129
F. host B IP address: 192.168.1.190

Correct Answers: A,C,F

Explanation:
It’s a “router-on-a-stick” configuration. Which means each host in the VLAN must corresponds with the VLAN configured on the sub-interfaces.
VLAN 10 is configured on fa0/0.10 and VLAN 20 on fa0/0.20. So each hosts in VLAN 10 must use fa0/0.10 IP address as their default gateway, each hosts must also be in the same subnet as fa0/0.10 IP – same with hosts in VLAN 20.
So find out the usable IP addresses on each sub-interfaces – for 192.168.1.78 /27: 192.168.1.65 – .94 and for 192.168.1.130 /26: 192.168.1.128 – .190.
Host A (using port 6 – VLAN 10) must use IP 192.168.1.79, default gateway 192.168.1.78.
Host B (using port 9 – VLAN 20) must use IP 192.168.1.190, default gateway 192.168.1.130.

CISCO CCNA Exam – Q130

Refer to the exhibit.
CISCO CCNA Exam – Q130

Which address range efficiently summarizes the routing table of the addresses for router Main?

A. 172.16.0.0./21
B. 172.16.0.0./20
C. 172.16.0.0./16
D. 172.16.0.0/18

Correct Answer: B

Explanation:
The 172.16.0.0./20 network is the best option as it includes all networks from 172.16.0.0 – 172.16.16.0 and does it more efficiently than the /16 and /18 subnets. The /21 subnet will not include all the other subnets in this one single summarized address.

CISCO CCNA Exam – Q129

Which IPv6 address is valid?

A. 2001:0db8:0000:130F:0000:0000:08GC:140B
B. 2001:0db8:0:130H::87C:140B
C. 2031::130F::9C0:876A:130B
D. 2031:0:130F::9C0:876A:130B

Correct Answer: D

Explanation:
An IPv6 address is represented as eight groups of four hexadecimal digits, each group representing 16 bits (two octets). The groups are separated by colons (:). An example of an IPv6 address is 2001:0db8:85a3:0000:0000:8a2e:0370:7334. The leading 0’s in a group can be collapsed using ::, but this can only be done once in an IP address.