Which suite of protocols is used to transmit data

The experimental network was so successful that many of the organizations attached to it began to use it for daily data communications. In the ARPAnet was converted from an experimental network to an operational network, and the responsibility for administering the network was given to the Defense Communications Agency DCA.

NSF wanted to extend the network to every scientist and engineer in the United States. To accomplish this, in NSF created a new, faster backbone and a three-tiered network topology that included the backbone, regional networks, and local networks.

Today the Internet is larger than ever and encompasses hundreds of thousands of networks worldwide. It is no longer dependent on a core or backbone network or on governmental support. National network providers, called tier-one providers, and regional network providers create the infrastructure.

The Internet has grown far beyond its original scope. The original networks and agencies that built the Internet no longer play an essential role for the current network. The Internet has evolved from a simple backbone network, through a three-tiered hierarchical structure, to a huge network of interconnected, distributed network hubs. It has grown exponentially since —doubling in size every year.

Originally it was used only as the name of the network built upon IP. Now internet is a generic term used to refer to an entire class of networks. The Internet protocols are often used for local area networking even when the local network is not connected to the Internet. They met an important need worldwide data communication at the right time, and they had several important features that allowed them to meet this need.

These features are:. Open protocol standards, freely available and developed independently from any specific computer hardware or operating system. Independence from specific physical network hardware.

Protocols are formal rules of behavior. In international relations, protocols minimize the problems caused by cultural differences when various nations work together. Similarly, when computers communicate, it is necessary to define a set of rules to govern their communications. In data communications, these sets of rules are also called protocols. But homogeneous networks are like the culture of a single country—only the natives are truly at home in it. Everyone is free to develop products to meet these open protocol specifications.

RFCs contain a wide range of interesting and useful information, and are not limited to the formal specification of data communications protocols.

Creating an official Internet standard is a rigorous process. Standards track RFCs pass through three maturity levels before becoming standards:. This is a protocol specification that is important enough and has received enough Internet community support to be considered for a standard.

The specification is stable and well understood, but it is not yet a standard and may be withdrawn from consideration to be a standard. This is a protocol specification for which at least two independent, interoperable implementations exist. A draft standard is a final specification undergoing widespread testing. It will change only if the testing forces a change. A specification is declared a standard only after extensive testing and only if the protocol defined in the specification is considered to be of significant benefit to the Internet community.

There are two categories of standards. A Technical Specification TS defines a protocol. An Applicability Statement AS defines when the protocol is to be used. There are three requirement levels that define the applicability of a standard:. This standard is optional. It is up to the software vendor to implement it or not. Two other requirements levels limited use and not recommended apply to RFCs that are not part of the standards track.

A protocol is " not recommended " when it has limited functionality or is outdated. There are three types of non-standards track RFCs:. An experimental RFC is limited to use in research and development. A historic RFC is outdated and no longer recommended for use. An informational RFC provides information of general interest to the Internet community; it does not define an Internet standard protocol. But there are several interesting FYI documents available. BCPs formally document techniques and procedures.

BCPs that provide operational guidelines are often of great interest to network administrators. There are now more than 3, RFCs.

As a network system administrator, you will no doubt read several. It is as important to know which ones to read as it is to understand them when you do read them.

To understand what you read, you need to understand the language of data communications. RFCs contain protocol implementation specifications defined in terminology that is unique to data communications. To discuss computer networking, it is necessary to use terms that have special meaning.

Even other computer professionals may not be familiar with all the terms in the networking alphabet soup. As is always the case, English and computer-speak are not equivalent or even necessarily compatible languages. Although descriptions and examples should make the meaning of the networking jargon more apparent, sometimes terms are ambiguous. A common frame of reference is necessary for understanding data communications terminology. An architectural model developed by the International Standards Organization ISO is frequently used to describe the structure and function of data communications protocols.

This architectural model, which is called the Open Systems Interconnect OSI Reference Model , provides a common reference for discussing communications. The OSI Reference Model contains seven layers that define the functions of data communications protocols. Each layer of the OSI model represents a function performed when data is transferred between cooperating applications across an intervening network.

Figure identifies each layer by name and provides a short functional description for it. Looking at this figure, the protocols are like a pile of building blocks stacked one upon another. Because of this appearance, the structure is often called a stack or protocol stack. A layer does not define a single protocol—it defines a data communications function that may be performed by any number of protocols.

Therefore, each layer may contain multiple protocols, each providing a service suitable to the function of that layer. For example, a file transfer protocol and an electronic mail protocol both provide user services, and both are part of the Application Layer.

Every protocol communicates with its peers. A peer is an implementation of the same protocol in the equivalent layer on a remote system; i. Peer-level communications must be standardized for successful communications to take place. In the abstract, each protocol is concerned only with communicating to its peers; it does not care about the layers above or below it. However, there must also be agreement on how to pass data between the layers on a single computer, because every layer is involved in sending data from a local application to an equivalent remote application.

The upper layers rely on the lower layers to transfer the data over the underlying network. Data is passed down the stack from one layer to the next until it is transmitted over the network by the Physical Layer protocols. At the remote end, the data is passed up the stack to the receiving application. The individual layers do not need to know how the layers above and below them function; they need to know only how to pass data to them. Isolating network communications functions in different layers minimizes the impact of technological change on the entire protocol suite.

New applications can be added without changing the physical network, and new network hardware can be installed without rewriting the application software. The InterNIC coordinates the registration of domain names through a group of worldwide registries. Most network protocol suites are structured as a series of layers, sometimes collectively referred to as a protocol stack. Each layer is designed for a specific purpose. Each layer exists on both the sending and receiving systems.

A specific layer on one system sends or receives exactly the same object that another system's peer process sends or receives. These activities occur independently from activities in layers above or below the layer under consideration. In essence, each layer on a system acts independently of other layers on the same system. Each layer acts in parallel with the same layer on other systems. Most network protocol suites are structured in layers.

The OSI model describes a structure with seven layers for network activities. One or more protocols is associated with each layer. The layers represent data transfer operations that are common to all types of data transfers among cooperating networks. The OSI model lists the protocol layers from the top layer 7 to the bottom layer 1. The following table shows the model. The OSI model defines conceptual operations that are not unique to any particular network protocol suite.

Other network protocols, such as SNA, add an eighth layer. The OSI model describes idealized network communications with a family of protocols. The table lists the layers from the topmost layer application to the bottommost layer physical network. Each system that is involved in a communication transaction runs a unique implementation of the protocol stack.

The physical network layer specifies the characteristics of the hardware to be used for the network. For example, physical network layer specifies the physical characteristics of the communications media. The Internet layer, also known as the network layer or IP layer , accepts and delivers packets for the network. IP is responsible for the following:. Host-to-host communications — IP determines the path a packet must take, based on the receiving system's IP address.

Packet formatting — IP assembles packets into units that are known as datagrams. Fragmentation — If a packet is too large for transmission over the network media, IP on the sending system breaks the packet into smaller fragments. IP on the receiving system then reconstructs the fragments into the original packet.

It is critical, since the packets travel individually following the most optimum path available. Each packet must include information about the sender, the receiver, the type of transmitted data and TTL to limit the lifetime of packet when attempting to contact an address.

In simple terms, that is how the data are transmitted in the computer networks. Physical layer - network access. The main layer receiving data from the next internet layer. It transmits data as a string of bits.

In practice, the physical layer is a network adaptor or a modem with drivers installed in the operating system.

It transport data packets from the server to the target device and vice versa. Key procedures related to establishing the connection between the devices are carried out in this layer. It does not guarantee correct data transfer. It provides communication between user applications. It controls the information flow and provides uninterrupted transfer of packets in a specific order. The data are divided into packets and identified with the sender, receiver and data type information. The receiving device sends a confirmation to the server after all packets are received.

Otherwise, the server will attempt to send the data package again. This layer is used by internet apps, e. The highest layer that allows applications to access the services of the other layers.

Correct functioning of the entire system also requires correct IP addressing. Each device connected to the internet must have a unique IP address. It applies to all the devices with direct access to the internet, e. IP addresses are divided into 5 classes and assigned depending on the type and application.

A protocol suite is a collection of protocols that are designed to work together. Protocol Stacks It is possible to write a single protocol that takes data from one computer application and sends it to an application on another computer. The approach used in networking is to create layered protocol stacks.

Lets take an example of a parcel service between two offices. The task is simple — send parcels between people in each office. We will divide the task into two distinct processes as follows: Take a package, wrap it and address it. Send it to the destination at the receiving end Receive the package Deliver it to the recipient Typically you would have an internal mail man that: Collects the parcels from the senders and takes then to a mail dispatch room. The parcels are placed in a van by the dispatcher and then driven to the remote office.

Please rate? And use Comments to let me know more. Best Kevin. Can you clarify on Which tools are used? Rgds Steve. Yes it can but it is more difficult to do. Hi steve, Thanks for the great explanation. Good Article. Everyone can get good explanation from the article. Leave a Reply Cancel reply Your email address will not be published. Leave this field empty.

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