Network+ OSI Layer 1-7

Question 1

What devices of the Layer 1 of the OSI model?

Answer 1

Layer 1: Physical layer
The physical layer is responsible for the transmission and reception of unstructured raw data between a device, such as a network interface controller, Ethernet hub, or network switch, and a physical transmission medium. It converts the digital bits into electrical, radio, or optical signals.

Question 2

What is the function of Layer 1 Physical Layer ?

Answer 2

The main function of Layer 1 is to convert digital data into physical signals.

Question 3

What is the function of Layer 2 of the OSI Model?

Answer 3

The data link layer (Layer 2) of the OSI moves data across a linked physical network. A layer 2 device on a computing network will transmit data to a destination according to Media Access Control (MAC) addresses, also known as Ethernet addresses.

which is responsible for managing access to physical media and managing data transmission between adjacent network nodes in a wide area network (WAN) or between nodes in an area network segment. same local (LAN). The process includes MAC (Media Access Control) and LLC (Logical Link Control).

Question 4

What is the device Layer 2 of the OSI Model?

Answer 4

A layer 2 device is a device that makes a forwarding decision on a physical address. Most commonly, you’ll find a bridge or a switch and the address they use is a MAC address.

Question 5

Which layer is responsible for detection of errors that occur over data transmission?

Answer 5

Additionally, the layer 2 can handle the detection and correction of errors that occur during data transmission. Checking is carried out using methods such as checksum or CRC (Cyclic Redundancy Check).

Question 6

Where does the Multilayer switch position in the OSI Layer?

Answer 6

Layer 3 Switch
It is also called a multilayer switch as it can work on Layer 2 and Layer 3, i.e., the data link layer and network layer of the OSI Model. Layer 3 switch can be configured to perform the routing function, which can also be used to route traffic between different VLANs or subnets within a VLAN.

Question 7

What is the Layer 3 of the OSI Model?

Answer 7

Layer 3 is the network layer. This is where we send information between and across networks through the use of routers. Instead of just node-to-node communication, we can now do network-to-network communication. Routers are the workhorse of Layer 3 - we couldn’t have Layer 3 without them.

Establishes, maintains and terminates network connections. Routes data packets across network segments. Translates logical addresses and names into physical addresses.

Question 8

What devices operate in Layer 3?

Answer 8

Routers, layer 3 (or IP) switches.

Question 9

What Protocol is used in Layer 3?

Answer 9

Distance Vector Multicast Routing Protocol (DVMRP)
Internet Group Management Protocol (IGMP)
Address Resolution Protocol (ARP)

Important Protocols at Network Layer include IPv4, IPv6, RIP, OSPF, BGP, ICMP, EIGRP, IPSec, IPX, NAT, GRE, HSRP & VRRP.

Question 10

What is the Layer 4 of the OSI model?

Answer 10

Layer 4 of the OSI model, also known as the transport layer, manages network traffic between hosts and end systems to ensure complete data transfers.

Question 11

What is the protocol used in Layer 4?

Answer 11

Transport-layer protocols such as TCP, UDP, DCCP, and SCTP are used to control the volume of data, where it is sent, and at what rate.

Question 12

What is the Layer 5 of the OSI model?

Answer 12

Session layer of OSI Model is designed to allow devices to establish and manage sessions so that multiple channels could be established between same terminals and hosts. Session Layer is the fifth layer in the 7-Layer OSI Model after Transport Layer. Session Layer is also called as ‘Port Layer’. The main function of Session Layer is to establish, maintain and synchronize the interaction between communicating systems and hosts like computers and servers. It allows information of different streams, originating from different sources, to be properly combined or synchronized.

Question 13

What are the functions and Duties of a Session Layer?

Answer 13

Sessions Management: It is Responsible for establishment, management and termination of sessions & connections between end user applications. It works in three phases:

• In the Session establishment phase, the service and the rules for communication between the two devices are proposed & agreed upon. For example, who transmits and when, how much data can be sent at a time etc.
• Once the rules are established, the data transfer phase begins.
• Finally, connection termination occurs when the session is
  complete, and communication ends gracefully.
• Duplex Control: Session Layer also controls that whether both sender/receiver of a session will communicate at same time or one will speak & other will listen
• Authentication (It is for Authentication b/w peer computers before the exchange happens e.g. simple username/password authentication
• Authorization (It confirms what a user is authorized to perform).

Question 14

What are the layer 5 Protocols?

Answer 14

SIP (Session Initiation Protocol)
PPTP - Point to point tunneling
H.245 (Call Control Protocol for Multimedia Communications)
PPTP/L2TP - Point to Point with Layer 2 Tunneling (VPN)
SMB (Server Message Block)
NFS (for Network File System)
PAP (Password Authentication Protocol)

Question 15

What are the Layer 5 Network Equipment?

Answer 15

Firewalls
Gateways
Computers
Load Balancers

Question 16

What is the Layer 6 of the OSI model?

Answer 16

Layer 6: presentation layer
Data formatting and encoding protocols apply at Layer 6 to ensure data is legible and presented properly in the application receiving it. Data compression is also a function of Layer 6. If necessary, data may be compressed to improve data throughput over network communication.

Converting data between different formats and ensuring end-to-end data integrity

If the devices are communicating over an encrypted connection, layer 6 is responsible for adding the encryption on the sender’s end as well as decoding the encryption on the receiver’s end so that it can present the application layer with unencrypted, readable data.

Question 17

What is the Layer 6 Protocols?

Answer 17

Protocols used include SSL/TLS, HTTPS, and SSH

Question 18

What is Layer 7 of the OSI Model?

Answer 18

Layer 7 - The Application Layer: The topmost layer of the OSI model, the application layer, serves as the interface for communication between users or processes and the network. It provides application-specific services such as HTTP requests, file transfer and email.

Responsible for providing end-user services, such as file transfer, web browsing, email, and chat.

Question 19

What application are used in Layer 7?

Answer 19

For the OSI model, let’s start at the top layer and work our way down. Layer 7 (Application): Most of what the user actually interacts with is at this layer. Web browsers and other internet-connected applications (like Skype or Outlook) use Layer 7 application protocols.