Datagram Transport Service - Computer Network - Lecture Slides, Slides of Computer Networks

Download Datagram Transport Service - Computer Network - Lecture Slides and more Slides Computer Networks in PDF only on Docsity!

COMPUTER

NETWORKS

Lecture-

Review Lecture 33

ICMP Message Transport

Using ICMP to Test Reachability

Using ICMP to Trace a Route

The Address Printed by Trace-route

Using ICMP for Path MTU Discovery

Terminology

 IP

Provides computer-to-computer communication Source and destination addresses are computers Called machine-to-machine

 Transport protocols

Provide application-to-application communication Need extended addressing mechanisms to identify applications Called end-to-end

Introduction

UDP: The first of the Transport Protocols in TCP/IP protocol suite

UDP protocol allows applications on the computers to send and receive datagrams.

UDP Packet Format

UDP uses best effort delivery service.

The User Datagram Protocol

TCP/IP contains two transport protocols:

UDP TCP

UDP- Less Complex and easier to understand

UDP- Does not provide the type of service a typical application expects

Characteristics of UDP

 End-to-end

 Connectionless

 Message-Oriented

 Best Effort Delivery

 Arbitrary Interaction

 Operating System Independent

Message-Oriented Interface

UDP offers application programs a

Message-Oriented Interface.

Does not divide messages into packets

for Transmission.

Does not combine messages for

delivery.

Message-Oriented Interface

Advantages:

Applications can depend on protocol to preserve data boundaries.

Disadvantage:

Each UDP message must fit into a single IP Datagram. Can result to an inefficient use of the underlying network.

Arbitrary Interaction

UDP follows four types of interaction:

1-to-

1-to- many

Many-to-

Many-to-many

Support for Unicast, Multicast,

and Broadcast

UDP allows multicast 1-to-many

interaction using multicast or a broadcast.

Sender uses a broadcast address as the

destination address to interact with MANY applications.

Especially useful for Ethernet Networks.

Endpoint Identification with

Protocol Port Numbers

UDP defines a set of identifiers called “Protocol Ports”.

Independent of the underlying operating system.

Each computer using UDP provides a mapping between the protocol port number and the program identifiers of its operating system.

Endpoint Identification with

Protocol Port Numbers

The address and protocol port

specifications of an application define the type of communication.

To engage in a 1-to-1 communication, the application specifies:

The Local Port Number

Remote IP Address

The Remote Port Number