Networking Essentials - Exam 2 (Chapter 5-8)

What is the purpose of protocols in data communications?

• specifying the bandwidth of the channel or medium for each type of communication
• specifying the device operating systems that will support the communication
• providing the rules required for a specific type of communication to occur
• dictating the content of the message sent during communication

Answer explanation

• Protocols provide rules that define how a message is transmitted across a network. Implementation requirements such as electronic and bandwidth details for data communication are specified by standards. Operating systems are not specified by protocols, but will implement protocols. Protocols determine how and when to send a message but they do not control the contents of a message.

Which two OSI model layers have the same functionality as two layers of the TCP/IP model? (Choose two.)

• data link
• network
• physical
• session
• transport

Answer explanation

• The OSI transport layer is functionally equivalent to the TCP/IP transport layer, and the OSI network layer is equivalent to the TCP/IP internet layer. The OSI data link and physical layers together are equivalent to the TCP/IP network access layer. The OSI session layer (with the presentation layer) is included within the TCP/IP application layer.

Which three layers of the OSI model map to the application layer of the TCP/IP model? (Choose three.)

• application
• presentation
• session
• data link
• transport

Answer explanation

• The application layer of the TCP/IP model maps to the top three layers of the OSI model, which are the application, presentation, and session layers.

Which type of network model describes the functions that must be completed at a particular layer, but does not specify exactly how each protocol should work?

• TCP/IP model
• protocol model
• reference model
• hierarchical design model

Answer explanation

• There are two common types of network communication models:
  

  • Protocol model - This model closely matches the structure of a particular protocol suite and describes the functions that occur at each layer of protocols within the suite. The TCP/IP model is an example of a protocol model.

  • Reference model - The primary purpose is to aid in a clearer understanding of the functions and processes necessary for network communications.This type of model does not specify exactly how a function should be accomplished. The OSI model is an example of a reference model.

The Institute of Electrical and Electronics Engineers is responsible for standards in which two areas? (Choose two.)

• TCP/IP technologies
• the OSI reference model
• wireless LANs
• peer-to-peer application compliance
• Ethernet media access control

Answer explanation

• Among the many standards for which the IEEE is responsible, the two major standards are IEEE 802.3 and IEEE 802.11. The IEEE 802.3 standard defines media access control (MAC) for wired Ethernet. The 802.11 standard defines a group of standards for implementing wireless local area networks (WLANs). The other options are standards that are developed and maintained by other standards organizations.

Which statement is true about MAC addresses?

• MAC addresses are implemented by software.
• A NIC only needs a MAC address if connected to a WAN.
• The first three bytes are used by the vendor assigned OUI.
• The ISO is responsible for MAC addresses regulations.

Answer explanation

• A MAC address is composed of 6 bytes. The first 3 bytes are used for vendor identification and the last 3 bytes must be assigned a unique value within the same OUI. MAC addresses are implemented in hardware. A NIC needs a MAC address to communicate over the LAN. The IEEE regulates the MAC addresses.

What is indicated by the 100 in the 100BASE-T standard?​

• meters
• feet
• megabits per second
• twists per meter

Answer explanation

• 100BASE-T is an Ethernet standard that translates to 100 megabits per second, baseband transmission, and twisted pair cable​.​

What process is used to place one message inside another message for transfer from the source to the destination?

• access control
• decoding
• encapsulation
• flow control

Answer explanation

• Encapsulation is the process of placing one message format into another message format. An example is how a packet is placed in its entirety into the data field as it is encapsulated into a frame.

Which logical address is used for delivery of data to a remote network?

• destination MAC address
• destination IP address
• destination port number
• source MAC address
• source IP address

Answer explanation

• The destination IP address is used for end-to-end delivery of data to a remote network. The destination MAC address is used for delivery on a local network. The destination port number identifies the application that should process the data at the destination. Source addresses identify the sender of the data.

What are the three layers of a hierarchical network design model? (Choose three.)

• Internet
• access
• core
• application
• distribution

Answer explanation

• The Cisco hierarchical network design model divides the network into three distinct layers. The access layer provides connectivity for the users. The distribution layer is used to forward traffic from one local network to another. The core layer represents a high-speed backbone layer between networks. The network layer is part of the OSI model. The Internet layer is part of the TCP/IP model. The application layer is part of both the OSI and TCP/IP models.