1. THE TRANSPORT LAYER
Scott Garland
COSC 352

2. WHAT IS IT? Under the TCP/IP Model Under the OSI Model
2ND highest layer in the TCP/IP model.
Responds to service requests from the Application Layer
Issues requests to the Internet Layer
Under the OSI Model
4th layer of the OSI Model
Responds to service requests from the Session Layer
Issues service requests to the Network Layer

3. OVERALL FUNCTIONS RECALL UPPER LEVEL LAYER FUNCTIONS**
TRANSPORT LAYER FUNCTIONS**
Doesn’t care about the “nuts and bolts”
Acts as a liaison
Enables communication between software applications on different computers.
Makes sure many different applications can all send and receive data.

4. Transfer protocol Typical protocols within Transport Layer
TCP (Transmission Control Protocol):
provides reliable, in-order delivery of a stream of bytes.**
UDP (User Diagram Protocol):
programs on networked computers can send short messages known as datagrams (packets) to one another.**
DCCP (Datagram Congestion Control Protocol:
works with timing constraints on the delivery and reliable in-order delivery.**
SCTP (Stream Control Transmission Protocol):
conserves message boundaries by operating on whole messages instead of single bytes.**

5. SERVICES UNDER TCP/IP MODEL
Same Order Delivery
Connection-Oriented
Reliable Data
Flow Control
Congestion Avoidance
Byte Orientation
Ports

6. SERVICES UNDER OSI MODEL
Flow Control/Connection-Oriented
Segmentation/Desegmentation
Error Control

7. Citations
ntro_to_networking/c4412.htm
Guide to Networking Essentials, Greg Tomsho