Transport layer and Application Layer
Slide 1
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Addressing and Protocols
Application Layer
Port Address
Logical Address
Physical Address
Michael Chai; Behrouz Forouzan
Transport Layer
Network Layer
DNS, FTP,TFTP, SNMP,
HTTP
SCTP, TCP, UDP
ICMP, IGMP, ARP, RARP
Physical and Data
Link Layers
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Transport Layer
Application Layer
Port Address
Logical Address
Physical Address
Michael Chai; Behrouz Forouzan
Transport Layer
Network Layer
DNS, FTP,TFTP, SNMP,
HTTP
SCTP, TCP, UDP
ICMP, IGMP, ARP, RARP
Physical and Data
Link Layers
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Transport 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
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Transport Layer
Domain of Transport Protocol
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
IP address versus Port address
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Socket Address
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
User 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)

Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
UDP Port addresses
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
TCP – Handling many connections
The addition of connect instance id codes makes multiple simultaneous connections
possible.
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Transmission 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

Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
TCP Ports
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Application Layer
Application Layer
Port Address
Logical Address
Physical Address
Michael Chai; Behrouz Forouzan
Transport Layer
Network Layer
DNS, FTP,TFTP, SNMP,
HTTP
SCTP, TCP, UDP
ICMP, IGMP, ARP, RARP
Physical and Data
Link Layers
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Domain 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.
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
DNS
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Domains
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Domain Name and Label
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
DNS Server

Stores domain name space information within its
domain/sub-domain.
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
File 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.
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
FTP
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
FTP Mechanism
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
Simple 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.

Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing
IADCN - Week 5
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.

Slide 25
Michael Chai; Behrouz Forouzan
13/04/2015
Staffordshire University
School of Computing