1. Which two characteristics describe Ethernet technology? (Choose two.)
- It typically uses an average of 16 Mb/s for data transfer rates.
- It uses a ring topology.
- It uses the CSMA/CD access control method.
- It is supported by IEEE 802.3 standards.
- It is supported by IEEE 802.5 standards.
Explanation: The 802.3 Ethernet standard specifies that a network implement the CSMA/CD access control method.
2. What are two services provided by the OSI network layer? (Choose two.)
- performing error detection
- routing packets toward the destination
- encapsulating PDUs from the transport layer
- placement of frames on the media
- collision detection
Explanation: The OSI network layer provides several services to allow communication between devices:
- addressing
- encapsulation
- routing
- de-encapsulation
Error detection, placing frames on the media, and collision detection are all functions of the data ink layer.
3. How do hosts ensure that their packets are directed to the correct network destination?
- They always direct their packets to the default gateway, which will be responsible for the packet delivery.
- They send a query packet to the default gateway asking for the best route.
- They search in their own local routing table for a route to the network destination address and pass this information to the default gateway.
- They have to keep their own local routing table that contains a route to the loopback interface, a local network route, and a remote default route.
Explanation: Hosts must maintain their own local routing table to ensure that network layer packets are directed to the correct destination network. This local table typically contains a route to the loopback interface, a route to the network that the host is connected to, and a local default route, which represents the route that packets must take to reach all remote network addresses.
4. A technician uses the ping 127.0.0.1 command. What is the technician testing?
- physical connectivity of a particular PC and the network
- connectivity between a PC and the default gateway
- connectivity between two PCs on the same network
- the TCP/IP stack on a network host
- connectivity between two adjacent Cisco devices
Explanation: 127.0.0.1 is the local loopback address on any TCP/IP network device. By pinging this address, the technician is verifying the TCP/IP protocol stack on that particular device.
5. What is the correct compressed format of the IPv6 address 2001:0db8:eeff:000a:0000:0000:0000:0001?
- 2001:db8:eeff:a:::1
- 2001:db8:eeff:a::1
- 2001:db8:eeff:a::0001
- 2001:db8:eeff:a:1
Explanation: There are two rules for IPv6 address compression. Rule 1: leading zeros in any hextet can be removed. Rule 2: contiguous hextets of all zeros can be compressed to a double colon. Rule two can only be applied once.
6. Which function or operation is performed by the LLC sublayer?
- It is responsible for media access control.
- It communicates with upper protocol layers.
- It performs data encapsulation.
- It adds a header and trailer to a packet to form an OSI Layer 2 PDU.
Explanation: The Ethernet LLC sublayer has the responsibility to handle communication between the upper layers and the lower layers of the protocol stack. The LLC is implemented in software and communicates with the upper layers of the application to transition the packet to the lower layers for delivery.
7. How many usable IP addresses are available on the 192.168.1.0/27 network?
- 32
- 30
- 16
- 62
- 254
- 256
Explanation: A /27 mask is the same as 255.255.255.224. This leaves 5 host bits. With 5 host bits, 32 IP addresses are possible, but one address represents the subnet number and one address represents the broadcast address. Thus, 30 addresses can then be used to assign to network devices.
8. Refer to the exhibit. Consider the IP address configuration shown from PC1. What is a description of the default gateway address?
- It is the IP address of the ISP network device located in the cloud.
- It is the IP address of the Router1 interface that connects the company to the Internet.
- It is the IP address of the Router1 interface that connects the PC1 LAN to Router1.
- It is the IP address of Switch1 that connects PC1 to other devices on the same LAN.
Explanation: The default gateway is used to route packets destined for remote networks. The default gateway IP address is the address of the first Layer 3 device (the router interface) that connects to the same network.
9. What is the command netstat -r used for?
- to display the TCP sockets
- to release the assigned IP address
- to display the host routing table
- to renew the default gateway
Explanation: The command netstat -r displays the host routing table to verify the routes and costs that a computer uses to communicate to certain networks.
10. A device has an IPv6 address of 2001:0DB8:75a3:0214:0607:1234:aa10:ba01 /64. What is the host identifier of the device?
- ba01
- 2001:0DB8:75a3
- 0607:1234:aa10:ba01
- 2001:0DB8
Explanation: An IPv6 address is made up of 128 bits that are represented as eight blocks of four hexadecimal digits that are called hextets. Because each hexadecimal digit represents four bits, each hextet represents 16 bits. The /64 network prefix indicates that the first 64 bits, or first four hextets, represent the network portion of the address. Because there are 128 bits in an IPv6 address, this leaves the last 64 bits, or last four hextets, to represent the host identifier. The value for the last four hextets is 0607:1234:aa10:ba01.
11. Which statement describes a MAC address?
- It identifies the source and destination addresses of hosts on the Internet.
- It is 128-bits in length.
- It is a physical address assigned to an Ethernet NIC by the manufacturer.
- It contains two portions, the network portion and the host portion.
Explanation: The Media Access Control (MAC) address is a physical address assigned to each Ethernet NIC by manufacturers. It is 48-bits in length. The MAC address is used to identify the source and destination on a local Ethernet network. It cannot be routed to remote networks.
12. Why does a Layer 3 device perform the ANDing process on a destination IP address and subnet mask?
- to identify the broadcast address of the destination network
- to identify faulty frames
- to identify the host address of the destination host
- to identify the network address of the destination network
Explanation: ANDing allows us to identify the network address from the IP address and the network mask.
13. What are two characteristics of IP? (Choose two.)
- retransmits packets if errors occur
- does not require a dedicated end-to-end connection
- operates independently of the network media
- guarantees delivery of packets
- re-assembles out of order packets into the correct order at the receiver end
Explanation: The Internet Protocol (IP) is a connectionless, best effort protocol. This means that IP requires no end-to-end connection nor does it guarantee delivery of packets. IP is also media independent, which means it operates independently of the network media carrying the packets.
14. Which three IP addresses are private ? (Choose three.)
- 172.32.5.2
- 192.167.10.10
- 172.16.4.4
- 192.168.5.5
- 10.1.1.1
- 224.6.6.6
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