Functions of the Transport layer
- Error Control
- Flow Control
- Addressing
- Segmentation and Resembling
- Duplication & Loss Control
Error Control
Error control is performed end-to-end in the transport layer to ensure that the receiving transport layer gets the message without any error. The transport layer performs the error correction through retransmission.
Flow Control
Flow control keeps the sender from sending too much data to the recipient. When a receiver is overwhelmed with data, it discards packets and requests for retransmission of that packet. As a result, network congestion grows, lowering system performance. The transport layer handles flow control. It employs the sliding window protocol, which improves data transmission efficiency while controlling data flow to avoid overloading the receiver. Instead of being frame-oriented, the sliding window protocol is byte-oriented.
Addressing
In many protocol session layers, the presentation and application layers are combined into a single layer known as the application layer. Delivery to the session layer in these circumstances implies delivery to the application layer. Data generated by one machine's process must be sent to the correct process on another device. The transport layer is responsible for addressing in this case. The transport layer attaches a header that contains the service point address (port address) to ensure that packet is delivered to the correct process.
Segmentation and Resembling
A message is broken down into segments that can be transmitted. Each segment has a sequence number that allows the transport layer to reassemble the message. When the message arrives at its destination, it is reconstructed correctly, and packets lost during transmission are replaced.
Duplication & Loss Control
The transport layer ensures that no duplicate data arrive at the destination. Sequence numbers are used to identify missing packets and identify and delete identical segments by the transport layer at the receiver end.
You can read related articles such as Congestion Control in Computer Networks here.
Must Read Subnetting in Computer Networks
Frequently Asked Questions
List all layers of the TCP/IP model?
There are seven layers in the OSI model. They are:
Physical layer
Data link layer
Network layer
Transport layer
Application layer
What is the Simplex mode?
The communication is unidirectional in Simplex mode. Only one of the devices on a link can be a sender, and the other can only receive.
What is Half-duplex and Full-duplex mode?
Both the devices can act as a sender or receiver in half-duplex mode. But at a time only one device can transmit data over the link.
Full-duplex mode is bi-directional, i.e. both devices can send or receive data at the same time.
List most common network topologies?
Some of the most common network topologies are:
Mesh topology
Bus topology
Star topology
Ring topology
Conclusion
Cheers if you reached here!!
In this article, we discussed the Transport layer in computer networks. We also looked at the various service provided by the transport layer.
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