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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.