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8. Definition of Protocol (Chapter 8)

8. Understand network protocols.  

8.1 Define network protocol. 

8.2 Describe the main elements of protocol.  

8.3 Describe the characteristics of protocol. 

8.4 Describe the functions of protocol. 

8.5 List different types of network protocols. 

8.6 State the function of TCP/IP protocol. 


8.1 Definition of Protocol

Protocol. A protocol is a standard set of rules that allow electronic devices to communicate with each other. These rules include what type of data may be transmitted, what commands are used to send and receive data, and how data transfers are confirmed. 

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প্রোটোকল কি

যে পদ্ধতির মাধ্যমে কমিউনিকেশন সিস্টেমে কম্পিউটার এবং বিভিন্ন ডিভাইস বা ডেটা ট্রান্সমিট পদ্ধতি সফটওয়্যারের মাধ্যমে নিয়ন্ত্রণ করা হয় তাকে প্রোটোকল বলে। বিভিন্ন প্রতিষ্ঠান বিভিন্ন ধরণের প্রোটোকল তৈরি করেছে। যেমনঃ FTP (File Transferr Protocol), NETBUEI, AppleTalk,TCP/IP ইত্যাদি। এদের মধ্যে ইন্টারনেট ব্যবহৃত প্রোটোকল হচ্ছে TCP/IP (Transmission Control Protocol / Internet Protocol). )


8.2 Describe the main elements of protocol.  

The key elements of a protocol are syntax, semantics, and timing.

Key Elements of Protocol

  1. Syntax,
  2. Semantics, and
  3. Timing.

1. Syntax

The term syntax refers to the structure or format of the data, meaning the order in which they are presented.

For example, a simple protocol might expect the first 8 bits of data to be the address of the sender, the second 8 bits to be the address of the receiver, and the rest of the stream to be the message itself.

2. Semantics

The word semantics refers to the meaning of each section of bits. How is a particular pattern to be interpreted, and what action is to be taken based on that interpretation?

For example, does an address identify the route to be taken or the final destination of the message?

3. Timing

The term timing refers to two characteristics: when data should be sent and how fast they can be sent.

For example, if a sender produces data at 100 Mbps but the receiver can process data at only 1 Mbps, the transmission will overload the receiver and some data will be lost.


8.3 DESCRIBE THE CHARACTERISTICS OF PROTOCOL.

Some important characteristics of a protocol are as  follows

  1. Direct/indirect
  2. Monolithic/structured
  3. Symmetric/asymmetric
  4. Standard/nonstandard

Chapter 2 Protocols and Architecture - ppt download

8.4 DESCRIBE THE FUNCTIONS OF PROTOCOL.

We can group protocal functions into the following categories

  1. Encapsulation
  2. Segmentation and reassembly
  3. Conncetion  Control
  4. Ordered delivery
  5. Flow control
  6. Error control
  7. Addressing
  8. Multiplexing
  9. Transmission


8.5 List different types of network protocols. 

There are various types of protocols that support a major and compassionate role in communicating with different devices across the network. These are:

1.     Transmission Control Protocol (TCP)

2.     Internet Protocol (IP)

3.     User Datagram Protocol (UDP)

4.     Post office Protocol (POP)

5.     Simple mail transport Protocol (SMTP)

6.     File Transfer Protocol (FTP)

7.     Hyper Text Transfer Protocol (HTTP)

8.     Hyper Text Transfer Protocol Secure (HTTPS)

9.     Telnet

10. Gopher

Let's discuss each of them briefly:

1.     Transmission Control Protocol (TCP): TCP is a popular communication protocol which is used for communicating over a network. It divides any message into series of packets that are sent from source to destination and there it gets reassembled at the destination.

2.     Internet Protocol (IP): IP is designed explicitly as addressing protocol. It is mostly used with TCP. The IP addresses in packets help in routing them through different nodes in a network until it reaches the destination system. TCP/IP is the most popular protocol connecting the networks.

3.     User Datagram Protocol (UDP): UDP is a substitute communication protocol to Transmission Control Protocol implemented primarily for creating loss-tolerating and low-latency linking between different applications.

4.     Post office Protocol (POP): POP3 is designed for receiving incoming E-mails.

5.     Simple mail transport Protocol (SMTP): SMTP is designed to send and distribute outgoing E-Mail.

6.     File Transfer Protocol (FTP): FTP allows users to transfer files from one machine to another. Types of files may include program files, multimedia files, text files, and documents, etc.

7.     Hyper Text Transfer Protocol (HTTP): HTTP is designed for transferring a hypertext among two or more systems. HTML tags are used for creating links. These links may be in any form like text or images. HTTP is designed on Client-server principles which allow a client system for establishing a connection with the server machine for making a request. The server acknowledges the request initiated by the client and responds accordingly.

8.     Hyper Text Transfer Protocol Secure (HTTPS): HTTPS is abbreviated as Hyper Text Transfer Protocol Secure is a standard protocol to secure the communication among two computers one using the browser and other fetching data from web server. HTTP is used for transferring data between the client browser (request) and the web server (response) in the hypertext format, same in case of HTTPS except that the transferring of data is done in an encrypted format. So it can be said that https thwart hackers from interpretation or modification of data throughout the transfer of packets.

9.     Telnet: Telnet is a set of rules designed for connecting one system with another. The connecting process here is termed as remote login. The system which requests for connection is the local computer, and the system which accepts the connection is the remote computer.

10. Gopher: Gopher is a collection of rules implemented for searching, retrieving as well as displaying documents from isolated sites. Gopher also works on the client/server principle.


8.6 State the function of TCP/IP protocol. 

TCP/IP, or the Transmission Control Protocol/Internet Protocol, is a suite of communication protocols used to interconnect network devices on the internet. TCP/IP can also be used as a communications protocol in a private computer network 

The two main protocols in the Internet Protocol suite serve specific functions. TCP defines how applications can create channels of communication across a network. It also manages how a message is assembled into smaller packets before they are then transmitted over the internet and reassembled in the right order at the destination address.

IP defines how to address and route each packet to make sure it reaches the right destination. Each gateway computer on the network checks this IP address to determine where to forward the message.

TCP/IP functionality is divided into four layers, each of which include specific protocols:

  • The application layer provides applications with standardized data exchange. Its protocols include the HTTP, FTP, Post Office Protocol 3 (POP3), Simple Mail Transfer Protocol (SMTP) and Simple Network Management Protocol (SNMP). At the application layer, the payload is the actual application data.
  • The transport layer is responsible for maintaining end-to-end communications across the network. TCP handles communications between hosts and provides flow control, multiplexing and reliability. The transport protocols include TCP and User Datagram Protocol (UDP), which is sometimes used instead of TCP for special purposes.
  • The network layer, also called the internet layer, deals with packets and connects independent networks to transport the packets across network boundaries. The network layer protocols are the IP and the Internet Control Message Protocol (ICMP), which is used for error reporting.
  • The physical layer, also known as the network interface layer or data link layer, consists of protocols that operate only on a link -- the network component that interconnects nodes or hosts in the network. The protocols in this lowest layer include Ethernet for local area networks (LANs) and the Address Resolution Protocol (ARP).


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TCP/IP

টিসিপি/আইপি হলো ইন্টারনেট ব্যবহারের জন্য প্রটোকল স্যুট ।  এই প্রটোকল স্যুটে দুটি প্রটোকলের নাম দেওয়া হয়েছে। এই প্রটোকল দুটি হলো : ট্রান্সমিশন কন্ট্রোল প্রটোকল (TCP) ও ইন্টারনেট প্রটোকল (IP)। TCP ব্যবহৃত হয় কানেকশন-অরিয়েন্টেড নির্ভরযোগ্য ট্রান্সমিশন সার্ভিসের জন্য, আর IP ব্যবহৃত হয় ওই নেটওয়ার্কের প্রতিটি হোস্টের এড্রেস নির্ধারণের জন্য।

টিসিপি কি?

টিসিপি হলো ট্রান্সমিশন কন্ট্রোল প্রটোকল । ইহা কানেকশন ওরিয়েন্টেড একটি একুনলেজ সিগন্যাল এর মাধ্যাম কানেকশন তৈরি করে থাকে।


টিসিপি হলো ট্রান্সমিশন কন্ট্রোল প্রটোকল । ইহা কানেকশন ওরিয়েন্টেড একটি একুনলেজ সিগন্যাল এর মাধ্যাম কানেকশন তৈরি করে থাকে।




টিসিপি/আইপি হলো ইন্টারনেট ব্যবহারের জন্য প্রটোকল স্যুট ।  এই প্রটোকল স্যুটে দুটি প্রটোকলের নাম দেওয়া হয়েছে। এই প্রটোকল দুটি হলো : ট্রান্সমিশন কন্ট্রোল প্রটোকল (TCP) ও ইন্টারনেট প্রটোকল (IP)। TCP ব্যবহৃত হয় কানেকশন-অরিয়েন্টেড নির্ভরযোগ্য ট্রান্সমিশন সার্ভিসের জন্য, আর IP ব্যবহৃত হয় ওই নেটওয়ার্কের প্রতিটি হোস্টের এড্রেস নির্ধারণের জন্য।












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