Pace IT - Introduction to the Transport Layer

Introduction to the transport layer.

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Instructor, PACE-IT Program – Edmonds Community College

Areas of Expertise Industry Certifications

PC Hardware

Network Administration

IT Project Management

Network Design

User Training

IT Troubleshooting

Qualifications Summary

Education

M.B.A., IT Management, Western Governor’s University

B.S., IT Security, Western Governor’s University

Entrepreneur, executive leader, and proven manger

with 10+ years of experience turning complex issues

into efficient and effective solutions.

Strengths include developing and mentoring diverse

workforces, improving processes, analyzing

business needs and creating the solutions

required— with a focus on technology.

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PACE-IT

– Introducing the transport layer.

– Introduction to TCP.

– Introduction to UDP.

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– The transport layer.» Most networking models follow the Open System

Interconnect (OSI) model.

• It is composed of seven different layers: application,

presentation, session, transport, network, data link, and

physical.

• The layers work together to create a system of

communication that allows different types of computing

systems or networks to communicate with each other.

» Layer 4, or the transport layer, receives data from the session

layer (Layer 5) and determines what method (or type) of

delivery is required for the data.

• The transport layer then hands the data (with the instructions

for method of delivery) to Layer 3 (the network layer), which is

responsible for determining where the data is going.

– The transport layer’s protocols.» There are two main protocols used by the transport layer.

• TCP and UDP.

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– Introduction to TCP (Transmission

Control Protocol).» A protocol that determines the type of delivery method

that will be used in network communication.

» TCP uses a reliable method to deliver network packets.

» TCP helps to set up the connection session.

» It establishes error control.

» It helps to tear down the network session.

– Reliable delivery method.» It uses a 3-way handshake.

• 1) requests the connection, 2) receives the response

from the other end, and 3) sends an acknowledgement

back that sets the sequence number that will be used.

» Every packet that gets sent must be acknowledged by

the receiver. If the sender doesn’t receive the

acknowledgement of a packet, the sender will resend the

packet.

» All packets are sent and received in order.

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– Introduction to UDP (User Datagram

Protocol).» A protocol that determines the type of delivery method that will

be used in network communication.

» UDP uses an unreliable method to deliver network packets.

» It doesn’t help to set up the connection session.

» It doesn’t establish error control.

» It doesn’t help to tear down the network session.

– Unreliable delivery method.» Could be better described as a “best effort” delivery method.

» It sends the data steam to the destination, trusting that the

destination is:

• A) listening for the data stream.

• B) willing to accept the data stream.

» The data steam flows with no acknowledgement of it being

received.

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Not all communication can be treated the same; that is why there are both reliable and unreliable delivery methods.

With TCP, the sender can be assured that the other end of the

line has received all of the packets that were sent and that the

packets were received in the proper order. This works well for

communication that is not sensitive to latency issues that are

associated with the overhead of reliable deliveries.

UDP strips off the overhead, but sacrifices reliability. It is well

suited for network communication in which speed is more

important than reliability. When using VoIP, it is more important


for the flow of packets to be continuous than to be held up

while waiting for packets to arrive in the right order (VoIP

communication can survive the occasional dropped packet).

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The transport layer is Layer 4 of the OSI model. It is responsible for

determining the method of delivery that will be used to send packets across

the network. The method may be reliable (TCP) or unreliable (UDP).

Topic

Introducing the transport

layer.

Summary

TCP is a reliable method of packet delivery. It helps to set up the

connection, it provides for error control, and it helps to tear down the

communication session. A 3-way handshake is used to establish a

connection and set the sequence number. Each packet that is sent must be

acknowledged or it is resent.

Introduction to TCP.

UDP is an unreliable (best effort) method of packet delivery. It assumes that

the receiver will be listening for and willing to accept the data stream. It

doesn’t care if packets get lost or arrive out of order. UDP is used because

some communications suffer due to TCP’s overhead.

Introduction to UDP.


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THANK YOU!

This workforce solution was 100 percent funded by a $3 million grant awarded by the

U.S. Department of Labor's Employment and Training Administration. The solution was

created by the grantee and does not necessarily reflect the official position of the U.S.

Department of Labor. The Department of Labor makes no guarantees, warranties, or

assurances of any kind, express or implied, with respect to such information, including

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or ownership. Funded by the Department of Labor, Employment and Training

Administration, Grant #TC-23745-12-60-A-53.

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