Cisco CCNA OSI and TCP/IP Models 5

Question 1

Which OSI layer is responsible for establishing, maintaining, and terminating sessions between applications?

Accepted Answer

Session (Layer 5)

Answer

The Session layer (Layer 5) controls the establishment, management, and termination of communication sessions between applications.

Question 2

In the context of the OSI model, what is a 'service data unit' (SDU)?

Accepted Answer

The data passed from a higher layer to a lower layer for encapsulation

Answer

A Service Data Unit (SDU) is the payload (data) that a layer receives from the layer above it before adding its own header to form a PDU.

Question 3

Which of the following correctly maps OSI layers to their corresponding TCP/IP model layers?

Accepted Answer

OSI Data Link + Physical = TCP/IP Network Access

Answer

The TCP/IP Network Access layer combines both the OSI Physical (Layer 1) and Data Link (Layer 2) layers into a single layer.

Question 4

When a host sends data using TCP, at which OSI layer is the segment header added?

Accepted Answer

Layer 4 - Transport

Answer

TCP is a Transport layer (Layer 4) protocol, and the TCP header (containing source/destination ports, sequence numbers, etc.) is added at Layer 4.

Question 5

Which statement best describes the advantage of the layered OSI model?

Accepted Answer

It allows changes in one layer without affecting other layers

Answer

The layered OSI model allows each layer to be updated or changed independently (e.g., switching from IPv4 to IPv6 at Layer 3) without impacting other layers.

Cisco CCNA Practice Test

Cisco CCNA Practice Test

Cisco CCNA OSI and TCP/IP Models 5