1) Comparing OSI Model Network Functions Flashcards
A systems engineer configures IP addresses for a SOHO router. In doing so, the engineer uses calculations to determine addresses for two subnets. Which value does the engineer determine the binary value of 1010 relates to in hexadecimal?
A. A
B. 0
C. FF
D. 10
A. A
The character A is the hexadecimal representation of the decimal value of 10 and the binary value of 1010.
The value of 0 is a decimal value that corresponds to a hexadecimal value of 0 and also to the binary value of 0000.
The character FF is the hexadecimal value of 255 in decimal notation. This would sometimes be written as 0xFF for clarity. The binary representation is 11111111.
The hexadecimal value for the decimal value of 10 is not also 10. The binary value for the decimal value of 10 is 1010.
A systems administrator wants to ensure that port numbers are being appropriately assigned for each type of network application. What layer of the OSI model should the administrator be reviewing to ensure these actions are taken?
A. Network
B. Transport
C. Session
D. Application
B. Transport
At the transport layer on the sending host, the system packages data from the upper layers as a series of layer 4 protocol data units (PDUs). It is critical at this layer that all types of network applications be assigned the correct port number.
The network layer (layer 3) is responsible for moving data around a system of networks, known as an internetwork or the Internet.
The session layer (layer 5) represents functions that administer the process of establishing a dialog, managing data transfer, and then ending (or tearing down) the session.
The application layer (layer 7) is at the top of the OSI stack. An application-layer protocol does not encapsulate any other protocols or provide services to any protocol.
A communications engineer notices that every time it rains the signal becomes very degraded. Which layer of the OSI model is the engineer most likely troubleshooting?
A. Physical
B. Data Link
C. Transport
D. Application
A. Physical
The physical layer (PHY) of the OSI model (layer 1) is responsible for the transmission and receipt of the signals that represent bits of data from one node to another node. Wireless is one medium.
The data link layer (layer 2) is responsible for transferring data between nodes on the same logical segment.
At the transport layer on the sending host, the system packages data from the upper layers as a series of layer 4 protocol data units (PDUs), referred to as segments.
The application layer (layer 7) is at the top of the OSI stack. An application-layer protocol does not encapsulate any other protocols or provide services to any protocol.
An application developer is attempting to troubleshoot issues with ASCII conversion for their application. At which layer of the OSI model are they troubleshooting?
A. Application
B. Session
C. Data link
D. Presentation
D. Presentation
The presentation layer of the OSI model transforms data between the format required for the network and the format required for the application.
The application layer (layer 7) is at the top of the OSI stack. An application-layer protocol does not encapsulate any other protocols or provide services to any protocol.
The session layer (layer 5) represents functions that administer the process of establishing a dialog, managing data transfer, and then ending (or tearing down) the session.
The data link layer (layer 2) is responsible for transferring data between nodes on the same logical segment.
A network engineer is analyzing a specific network protocol. Which of the following are the principal functions of a network protocol? (Select all that apply.)
A. Addressing
B. Encapsulation
C. Network layer
D. Presentation
A. Addressing
B. Encapsulation
Addressing describes where data messages should go. At each layer, there are different mechanisms for identifying nodes and rules on how they can send and receive messages.
Encapsulation describes how the system should package data messages for transmission. Encapsulation is like an envelope for a letter, with the distinction that each layer requires its own envelope.
The network layer is the part of the OSI model which forwards information between networks by examining the destination network-layer address or logical network address.
The presentation layer of the OSI model transforms data between the format required for the network and the format required for the application.
A security engineer implements port security on a hardware firewall. Which OSI model layer identifies the application ports to configure?
A. Layer 1
B. Layer 2
C. Layer 3
D. Layer 4
D. Layer 4
The transport layer (layer 4) manages end-to-end communications. At layer 4, a port number identifies each application, such as 80 for hypertext transfer protocol (HTTP) web traffic.
Layer 1 (the physical layer) uses physical ports and cabling to connect and create a local area network.
Ethernet switching by using hardware-based media access control (MAC) addresses and wireless to wired bridging make use of physical layer adapters at layer 2.
At layer 3, the network layer, the routing part of the router (such as a SOHO router), makes forwarding decisions between the local private network and the public Internet.
C. CPEA junior IT technician configures a purchased private computer network for a small bakery. What is a SOHO router considered to be once it is placed in the building?
A. IXP
B. PSTN
C. CPE
D. IANA
C. CPE - Customer Premises Equipment
Customer premises equipment (CPE) is equipment owned, managed, and supported by the customer as it falls beyond the demarcation point.
The major infrastructure (or the backbone) of the Internet consists of high bandwidth trunks connecting Internet eXchange Points (IXPs).
The public switched telephone network is where the customer premise equipment connects to gain Internet access. Historically, a PSTN provided access by dial-up, but fiber and broadband have since replaced it.
Internet Assigned Numbers Authority (IANA) is an organization that manages the allocation of IP addresses and maintenance of the top-level domain space. Internet Corporation for Assigned Names and Numbers (ICANN) currently runs IANA.
A networking engineer is troubleshooting issues with a router. At which layer of the OSI model is the engineer troubleshooting?
A. Data link
B. Transport
C. Network
D. Session
C. Network
The main appliance working at layer 3 is the router. The network layer (layer 3) is responsible for moving data around a system of networks, known as an internetwork or the Internet.
The data link layer (layer 2) is responsible for transferring data between nodes on the same logical segment.
At the transport layer on the sending host, the system packages data from the upper layers as a series of layer 4 protocol data units (PDUs), referred to as segments.
The session layer (layer 5) represents functions that administer the process of establishing a dialog, managing data transfer, and then ending (or tearing down) the session.
A network administrator configures a SOHO router for a small business. Which zone and IP address information is configured on the router for proper functionality for users to access all internal resources and the Internet?
A. Zone: private
Internal IP range 192.168.51.0/24
Zone: public
External IP 209.0.113.1
B. Zone: public
Internal IP range 149.167.1.0/24
Zone: private
External IP 20.0.11.1
C. Zone: private
Internal IP range 182.168.19.0/24
Zone: public
External IP 188.4.11.1
D. Zone: public
Internal IP range 192.168.6.0/24
Zone: private
External IP 212.8.1.9
A. Zone: private
Internal IP Range 192.168.51.0/24
Zone: public
External IP 209.0.113.1
For the SOHO router to function properly for both internal network communications and access to the Internet, a private zone would use a private IP address range while a public zone would use a public IP.
In this instance, the zone for an internal range should be private and use a private address range. The zones get flipped, and the internal range becomes a public range.
In this instance, the zones are acceptable, however, the internal IP range is a public range.
In this instance, the IP address configurations are acceptable, however, the zone types are flipped.
