OSI Model interview questions and answers

OSI model is an important concept which is asked for network and security job interviews.Check out the list of OSI model interview questions and answers.

At which layer of the OSI model does ethernet frames come.

Ethernet frames comes at the data link layer of the OSI model.

What is the fundamental difference between TCP/IP and the OSI model.

The TCP/IP model is practically implemented. For example, operating systems have TCP/IP installed. OSI model is a theoretical reference model.

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Which layer in the OSI model is missing in the below image.

OSI MODEL IMAGE

The network layer is missing in the image.

A web browser is communicating with a web server. During this time a TCP connection is established. At which layer does this occur in the OSI model.

TCP connections occur at the transport layer. This is the layer where the connection establishment is done.

Provide an example where two layers in the OSI model is combined into one layer in the TCP/IP model.

The data link and physical layer in the OSI model is combined into the physical layer of the OSI model.

At which layer of the OSI model is the IP protocol implemented

IP protocol is implemented the network layer of the OSI model.

A user connects to a FTP server using FTP client on the PC. At which layer of the OSI model does this occur

The FTP client is an application which is installed on the PC. When the users connects to the FTP server using the client, application layer of the OSI model is in use.

Which layer in the TCP/IP model corresponds to the application layer in the OSI model

The application layer in the TCP/IP model corresponds to the application + presentation + session model in the OSI model.

Which layer in the OSI model does SSL VPN work

SSL VPN works at the application layer of the OSI model.

What is the name of the PDU in the data link layer of the OSI model

Frames.

What is the name of the PDU in the network layer of the OSI model

Packets.

At which layer of the OSI model does routers and switches work

Routers work at the network layer of the OSI model and switches work at the data link layer.

At which layer of the OSI model does hubs and access points work

Hubs work at the physical layer and access points work at the data link layer of the OSI model.

Name two protocols which work at the transport layer of the OSI model

TCP and UDP are two protocols which work at the transport layer. TCP is a connection oriented protocol and UDP is a connection less protocol.

Name two protocols which work at the network layer of the OSI model

IP and ICMP are two protocols which work at the network layer of the OSI model.

Which protocol does ping use at the network layer.

Ping uses ICMP at the network layer. IP is also used at the network layer for constructing the ping packets.

Which are the two common application layer protocols which are used by browsers.

Browsers use http and https protocols.

Which layer data in the OSI model is encrypted by SSL protocol

The application layer data in the OSI model is encrypted. SSL creates session keys which is used for encrypting the data.

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Which layer in the OSI model is responsible for delivery of data.

The network layer is used for delivery of data. Packets are used for this purpose.

A PC is connected to a switch using a cable. At which layer of the OSI model does the switch and PC come

The cable operates at the physical layer and the switch at the data link layer. The cable is used to provide physical connectivity with the switch whereas the switch is used to process frames.

How does the transport layer know to which application on the remote host the data has to be delivered

Protocols in the transport layer are predominantly TCP and UDP. The headers of these two protocols contains a field know as destination port. The destination port number identifies the application on the remote host to which the data has to be delivered. For example, a port number of 443 would indicate that the data has to be delivered to the web service on the remote host.

How does the network layer know the destination to be delivered.

The delivery at the network layer is done using packets. IP is the protocol which is used at the network layer. The IP header has a field which is the destination IP address. The value is this field will inform to which system the packet has to be delivered.

What is the PDU at the transport layer known as

The PDU at the transport layer is known as segments.

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