UGC NET CSE | December 2013 | Part 3 | Question: 45

Question

Which layer of OSI reference model is responsible for decomposition of messages and generation of sequence numbers to ensure correct re-composition from end to end of the network?

• A. Physical
• B. Data-link
• C. Transport
• D. Application

Answer 1

ans is C transport layer

Transport layer is the fourth layer in OSI Reference Model. It responds to service requests from Session layer and issues service requests to Network layer. Transport Layer is responsible for delivering messages between hosts. In Transport layer, data travels in the form of segments. Transport layer is responsible for creating an end to end connection between source IP and the destination IP. For establishing this end to end connection, Transport layer is using two major protocols TCP and UDP. TCP is connection oriented protocol where UDP is connection less protocol. So by using TCP we can create an end to end reliable connection between source and destination hosts. Transport layer is called host-to-host transport layer in TCP/IP model.

Comments

hahahaha u r very true

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 The Network Layer :

1. It routes the signal through different channels from one node to other.
2. It acts as a network controller. It manages the Subnet traffic.
3. It decides by which route data should take.
4. It divides the outgoing messages into packets and assembles the incoming packets into messages for higher levels

see this

http://www.studytonight.com/computer-networks/complete-osi-model

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"Correct recomposition from end to end" is asked -- Ans should be Transport Layer