13/09/2015 Michael Chai; Behrouz Forouzan Staffordshire University School of Computing Transport layer and Application Layer Slide 1

19/04/23Michael Chai; Behrouz Forouzan Staffordshire UniversitySchool of Computing

Transport layer and Application Layer

Slide 1


IADCN - Week 5Addressing and Protocols

DNS, FTP,TFTP, SNMP, HTTP

SCTP, TCP, UDP

ICMP, IGMP, ARP, RARP

Port Address

Logical Address

Physical Address

Application Layer

Transport Layer

Network Layer

Physical and Data Link Layers


IADCN - Week 5


IADCN - Week 5Transport Layer


SCTP, TCP, UDP


Port Address

Logical Address

Physical Address

Application Layer

Transport Layer

Network Layer




Starts and stops the connection of the transmission.– At the transmitter, it is responsible for chopping the stream

of data into transportable datagrams, numbering them and then sending them one by one.

– At the receiver, it is responsible for waiting until all datagrams have arrived, checking for errors and then processing as a stream.

Provides connection mechanism between two or more running application programs.– Transmission control protocol (TCP) with flow control

– User datagram protocol (UDP) with no flow control



Domain of Transport Protocol


IADCN - Week 5IP address versus Port address


IADCN - Week 5Socket Address


IADCN - Week 5User Datagram Protocol (UDP)

Simple protocol and limited overhead as compared to IP packet.

No additional services added into the IP packet, apart from starting and stopping the connection.

Connectionless and “unreliable” transport protocol. Independent datagram - not numbered Suitable for simple request-response communication

(Refer to the port number table for more info)


IADCN - Week 5UDP Port addresses


IADCN - Week 5TCP – Handling many connections

The addition of connect instance id codes makes multiple simultaneous connections possible.


IADCN - Week 5Transmission Control Protocol (TCP)

Connection-oriented protocol and reliable transport protocol.

Create a virtual connection between two application programs to send data.

Virtual connection – connected as in the transport layer


IADCN - Week 5


IADCN - Week 5TCP Ports


IADCN - Week 5Application Layer


SCTP, TCP, UDP


Port Address

Logical Address

Physical Address

Application Layer

Transport Layer

Network Layer



IADCN - Week 5Domain Name System (DNS)

Each terminal in network has an unique IP address and a name (name space).

A name space maps IP address to a unique name in either flat or hierarchical method.

DNS is used for designing hierarchical name space– Example of hierarchical name space: www.staffs.ac.uk,

www.fcet.staffs.ac.uk, gawains.staffs.ac.uk, blackboard.staffs.ac.uk

Maximum of 128 levels with maximum 63 characters in each node of the tree.


IADCN - Week 5DNS


IADCN - Week 5Domains


IADCN - Week 5Domain Name and Label


IADCN - Week 5DNS Server

Stores domain name space information within its domain/sub-domain.


IADCN - Week 5File Transfer Protocol

Standard protocol for copying a file from one host to another.

It standardises the data format and structure. Uses two TCP connections

– Port 21 for control connection

– Port 20 for data connection

Trivial File Transfer Protocol (TFTP) is used in simple and quickly copy file protocol that uses the UDP services.


IADCN - Week 5FTP


IADCN - Week 5FTP Mechanism


IADCN - Week 5Simple Network Management Protocol (SNMP)

A framework for managing devices in network using TCP/IP protocol suite.– Manager – SNMP client program installed in the server

– Agent – SNMP server program installed in the router or host

The SNMP client program can perform actions for monitoring and maintaining the performance of the network.

uses UDP services at port 161 and 162 for agent and manager respectively.


IADCN - Week 5

Slide 25

Conclusion We have discussed the major protocols in transport

and application layers of TCP/IP protocol suite. TCP and UDP are used for the connection mechanism

between two or more running application programs. The application layer components such as DNS, FTP,

TFTP and SNMP are the major components for networking programming.

Other components discussed in the previous week were Javascript, ASP script and Applet.

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13/09/2015 Michael Chai; Behrouz Forouzan Staffordshire University School of Computing Transport layer and Application Layer Slide 1