Protocols and Application Layer Protocols

Protocols

1

• Ethernet

• TCP

• IP

• UPD

• FTP

• SSH

• Telnet

• POP

• IMAP

• SMTP

• HTTP

• HTTPS

Describe a range of different protocols accessed by the application layer of the TCP/IP model

Give practical examples of how the different application layer protocols are used by network users.

Protocols 2

To improve the efficiency of transferring information over a shared communication line, messages are divided into fixed-sized, numbered packets

Network devices called routers are used to direct packets between networks

Protocols 3

A protocol is a set of rules to govern

communication within and between computers on a

network.

The main functions of protocols:

•Identifying errors

•Compressing the data

•Deciding how data is to be sent

•Addressing data

•Deciding how to announce sent and received data

Protocols used for browsing the web, sending and receiving e-mail, and

transferring data files.

Protocols 4

Network protocols are layered such that each one relies on the protocols that underlie it

Sometimes referred to as a protocol stack

Protocols 15-5

Protocols 6

Application Application

Network Network

Presentation Presentation

Data Link Data Link

Session Session

Transport Transport

Physical Physical

The International Organization for Standardization (ISO) established the Open Systems Interconnection (OSI) Reference Model

Each layer deals with a particular aspect of network communication

Protocols 15-7

Proprietary system A system that uses technologies kept private by a particular commercial vendor

One system couldn’t communicate with another, leading to the need for………….

Interoperability The ability of software and hardware on multiple machines and from multiple commercial vendors to communicate

Leading to…………….

Open systems Systems based on a common model of network architecture and a suite of protocols used in its implementation

Protocols 8

The TCP/IP (transport control protocol/internet protocol) cuts the 7 layers of the OSI model down to 4,

The protocol allows data packets to be routed and allows intercommunication between LANs and WANs,

All communication on the internet makes use of the TCP/IP protocol.

Protocols 9

Transport Transport

Network Network

Application Application

Link Link

TCP stands for Transmission Control Protocol

TCP software breaks messages into packets, hands them off to the IP software for delivery, and then orders and reassembles the packets at their destination

IP stands for Internet ProtocolIP software deals with the routing of packets through the maze of interconnected networks to their final destination

Protocols 10

Protocols 11

If IP routes the packets……

UDP stands for User Datagram Protocol

It is an alternative to TCP

The main difference is that TCP is highly reliable, at the cost of decreased performance, while UDP is less reliable, but generally faster

Protocols 15-

12

Other protocols build on the foundation established by the TCP/IP protocol suite

Simple Mail Transfer Protocol (SMTP)

File Transfer Protocol (FTP)

Telnet

Hyper Text Transfer Protocol (http)

Protocols 15-

13

Related to the idea of network protocols and standardization is the concept of a file’s MIME type

MIME stands for Multipurpose Internet Mail Extension

Based on a document’s MIME type, an application program can decide how to deal with the data it is given

Protocols 15-

14

15-

15

Describe a range of different protocols accessed by the application layer of the TCP/IP model

Give practical examples of how the different application layer protocols are used by network users.

Protocols 16

Protocol Research, give the full name, OSI layer and a brief description.

TCP

IP

UDP

HTTP

FTP

DNS

SSH

POP

IMAP

SMTP

Protocols 17

Protocols 18

Protocol Research and give a description

TCP Transmission control protocol. It is implemented in the transport layer of the IP/TCP

model and is used to establish reliable connections.

IP Internet Protocol addresses are unique on each network and they allow machines to

address each other across a network. It is implemented on the internet layer in the IP/TCP

model.

UDP User datagram protocol. It is a popular companion protocol to TCP and is also

implemented in the transport layer.

HTTP Hypertext transfer protocol. It is a protocol defined in the application layer that forms

the basis for communication on the web.

FTP File transfer protocol. It is also in the application layer and provides a way of transferring

complete files from one host to another.

DNS Domain name system. It is an application layer protocol used to provide a human-friendly

naming mechanism for internet resources.

SSH Secure shell. It is an encrypted protocol implemented in the application layer that can be

used to communicate with a remote server in a secure way.

POP A protocol used to download email messages from an email server.

IMAP A protocol used to download email messages from an email server.

SMTP A protocol used to send mail in a TCP/IP network.