Router operates in which layer of OSI reference model?

The router operates in which layer of OSI reference model?

(A). Session Layer

(B). Network Layer

(C). Presentation Layer

(D). Transport Layer

Correct Answer: Transport Layer

which of the following OSI layer is
which of the following OSI layer is

 Layers of the OSI Model

Layer Responsibility
7. Application Layer
  • Allows users to send data, access data, and use networks.
  • End User layer
  • Protocols:
    • File Transfer Protocol (FTP)
    • Simple Mail Transfer Protocol (SMTP)
    • Domain Name System (DNS)
    • IRC, HTTP
    • SSH, DNS
6. Presentation Layer
  • Presenting the data to the application layer Syntax layer
  • Data conversion
  • Character code translation
  • Data compression
  • Encryption and decryption


5. Session Layer
  • Responsible for opening sessions, ensuring they remain open and functional while data is being transferred, and closing them when communication ends.
  • Synch & send to port
  • WinSock, API’s, Sockets
  • Protocols:
    • Remote procedure call protocol (RPC)
    • Point-to-Point Tunneling Protocol (PPTP)
    • Session Control Protocol (SCP)
    • Session Description Protocol (SDP)


4. Transport Layer
  • Controls the reliability of a given link through flow control, segmentation and desegmentation, and error control.
  • End-to-end connections
  • Protocols: TCP, UDP
  • error control
  • flow control
  • congestion control
3. Network Layer
  • routing the data via the best physical path
  • Packets
  • Protocols: IPSec, ICMP, IGMP, IP, IPv4, IPv6.
  • Best available path
  • traffic controls
  •  congestion of data packets
  •  encapsulation and fragmentation
2. Data Link Layer


  • Responsible for multiplexing data streams, data frame detection, medium access, and error control.
  • Frames
  • Switch, PPP, Bridge, Ethernet
  • Media Access Control (MAC) Layer


1. Physical Layer


  • Responsible for the communication of the unstructured raw data streams over a physical medium
  • Hardware: Coaxial cable, Fiber optic cable, Repeaters, Wireless, Hubs
  • Topologies: Bus, Ring, Star, and Mesh topology
  • Communication modes: Simplex, Half Duplex, Full Duplex, etc
  • Data transmission performance: Bit Rate and Bit Synchronization