PACE-IT: The Transport Layer Plus ICMP

The transport layer plus ICMP.

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.

Brian K. Ferrill, M.B.A.


– TCP and UDP.

– ICMP (Internet Control Message Protocol).

PACE-IT.

TCP and UDP.The transport layer plus ICMP.

TCP and UDP.

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

Interconnection (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.


OSI Model

Layer 7 Application

Layer 6 Presentation

Layer 5 Session

Layer 4 Transport

Layer 3 Network

Layer 2 Data link

Layer 1 Physical

TCP and UDP.

– 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 three-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.


TCP and UDP.

– 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 stream 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.


TCP and UDP.

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 for communication


to be held up while waiting for packets to arrive in the right order (VoIP communication can survive the occasional dropped packet).

ICMP (Internet Control Message Protocol).The transport layer plus ICMP.

ICMP (Internet Control Message Protocol).

ICMP works at Layer 3, or the network layer, of the OSI model and it is used by IP (Internet Protocol) to perform several services.

As a messaging service for IP, its packets are carried as encapsulated IP datagrams. It provides information about networking issues.

The ping utility uses ICMP to test for end-to-end connectivity between two devices using ICMP echo request packets.

The tracert utility uses a combination of ICMP echo requests and destination unreachable packets to map the actual route between two endpoints.


If a router’s memory buffers are full, it will send out an ICMP Buffer Full message until the congestion has been reduced, allowing other routers to slow down to avoid packet loss.

What was covered.The transport layer plus ICMP.

The transport layer is the fourth layer of the OSI reference model. This layer is responsible for the delivery of network packets. The two main protocols used by the transport layer are TCP and UDP. TCP is a reliable delivery protocol that uses a variety of methods to ensure that the packets sent are delivered. UDP is an unreliable delivery protocol that transports network packets without regard to them being received.

Topic

TCP and UDP.

Summary

ICMP is a network layer protocol and functions as a messaging service and management protocol for IP. ICMP messages are encapsulated as IP datagrams. Both the ping and tracert utilities use ICMP to fulfill their functions. A router that is suffering from a full memory buffer will also use ICMP messages to inform other routers of the issue.

ICMP (Internet Control Message Protocol).

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 any information on linked sites and including, but not limited to, accuracy of the information or its completeness, timeliness, usefulness, adequacy, continued availability or ownership. Funded by the Department of Labor, Employment and Training Administration, Grant #TC-23745-12-60-A-53.

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PACE-IT: The Transport Layer Plus ICMP

Education

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