Switches, routers, and wireless access points are the basic elements of a network. A network uses these tools to connect devices and allows communication through them. These essential components perform very different functions and function akin to the human body. Each component is vital to ensure free flow of information.
Switches are the foundation of most business networks. A switch acts as a controller, connecting computers, printers, and servers to a network in a building or a campus. Switches allow devices on your network to communicate with each other, as well as with other networks, creating a network of shared resources, thus saving time and money.
Routers connect multiple networks together. They also connect computers on those networks to the Internet. Routers enable all networked computers to share a single Internet connection, which saves money. A router acts a dispatcher. It analyzes data being sent across a network, chooses the best route for data to travel, and sends it on its way.
An access point allows devices to connect to the wireless network without cables. Access points also act as amplifiers for a network. While a router provides the bandwidth, an access point extends that bandwidth so that the network can support many devices, and those devices can access the network from farther away.
Understanding network layout and topology
There are many ways network nodes can be connected together. Network topology assumes significance when the network gets bigger and new systems are added to it. Technologies like Bluetooth, Wi-Fi etc. are designed to work using specific topologies.
Some of the most common network topologies are:
* Bus: In bus topology, there is a main cable and all the devices are connected to this main cable through drop lines. There is a device called tap that connects the drop line to the main cable. Since all the data is transmitted over the main cable, there is a limit of drop lines and the distance a main cable can have.
* Ring: In ring topology, each device is connected with the two devices on either side of it. There are two dedicated point to point links a device has with the devices on the either side of it. If a device wants to send data to another device, then it sends the data in one direction. Each device in ring topology has a repeater, if the received data is intended for other device then repeater forwards this data until the intended device receives it.
* Mesh: In mesh topology, each device is connected to every other device on the network through a dedicated point-to-point link.
* Star: In star topology, each device in the network is connected to a central device called hub. Unlike mesh topology, star topology doesn’t allow direct communication between devices. Devices have to communicate via the hub.
* Hybrid: A combination of two or more topologies is known as hybrid topology. This topology is very versatile and allows scalability. Devices can be connected to other computer networks with existing networks having different topologies.
Networks also vary considerably in terms of the roles and responsibilities of the computers on that network and the relationships that tie those machines together.
Let’s take a look at some of the basic network variants:
When several computers are interconnected, but no computer occupies a privileged position, the network is usually referred to as a peer-to-peer network. In this type of network, every computer can communicate with all the other machines on the network, but, in general, each one stores its own files and runs its own applications.
With a client-server network, one or more servers will perform critical functions on behalf of the other machines (the clients) on the network. These functions might include user authentication, data storage, and the running of large, shared, resource-intensive applications such as databases and Client Relationship Management (CRM) software. Typically, both peer-to-peer and client-server networks rely on a shared Internet connection for access to external resources of these basic network structures.
This network model involves recruiting a third-party vendor to host data, applications and other resources on servers and manages those resources via a web browser. This network isn’t advisable for organizations that handle and store sensitive data like client information, financial, or health records. A cloud-based network is a simpler, greener, and cheaper alternative to a client-server network or a peer-to-peer network. Organizations using this network do not have to pay for the purchase, functioning, and maintenance of the servers.
Understanding standards and protocols
Protocols, also known as standards, are essential parts of many modern technologies. A protocol defines a set of rules that govern how computers talk to each other. Most networking protocols are fairly obscure, and you only need to worry about them if something goes wrong.
There are three sets of network protocols that are considered standard.
1. In local area networks, Ethernet over twisted pair (also known as 10 BASE T, twisted-pair Ethernet, or IEEE 802.3) is the accepted standard for wired networking.
2. For wireless network, 802.11b/g/n (or Wi-Fi) is the accepted standard.
3. The TCP/IP protocol stack is a standard component of almost all modern networks, especially when those networks expect to communicate on the Internet. TCP/IP networks are most common and considered most important.
Understanding network addressing
An Internet Protocol address (IP address) is a numerical label assigned to each device (e.g., computer, printer) participating in a computer network that uses the Internet Protocol for communication. Every device attached to a network, and the Internet has an IP address.
There are two versions of IP, they are IPv4 and IPv6. IPv4 has been in use since the start of the Internet, and is deployed across the Internet, and home/corporate networks. IPv4 uses 32 bits for addressing, however due to the rapid growth of the Internet, all IPv4 addresses have been allocated (as of 2013).
However, IPv4 will eventually be replaced by IPv6, which uses 128 bits for the address, and so can accommodate many more hosts (computers/devices). The roll out of IPv6 across the Internet is happening slowly, and IPv4 will be with us for quite some time. In the meanwhile, as IPv6 rolls out they will also be a need to operate with two addresses until migration is complete, and IPv4 is phased out.
IP address of any device is not fixed. Most modern networks use automatic IP address assignment via DHCP with manual assignment only being done in special cases. For home networks, the Internet router or hub usually provides DHCP services for the network. For larger networks, a dedicated DHCP server is normally used.
ICMP (Internet Control Message Protocol)
ICMP is used to send messages between devices to indicate the availability or error conditions. These packets are used in a variety of network diagnostic tools, such as ping and traceroute.
TCP (Transmission Control Protocol)
TCP is implemented in the transport layer of the IP/TCP model and is used to establish reliable connections. TCP is the protocol of choice for many of the most popular uses for the internet, including WWW, FTP, SSH, and email. The Internet we see today would not be the same without TCP.
UDP (User Datagram Protocol)
UDP is a popular companion protocol to TCP and is also implemented in the transport layer. The fundamental difference between UDP and TCP is that UDP offers unreliable data transfer. It does not verify that data has been received on the other end of the connection.
HTTP (Hypertext Transfer Protocol)
It is a protocol defined in the application layer that forms the basis for communication on the web. HTTP defines a number of functions that tell the remote system what a user requesting. For instance, GET, POST, and DELETE all interact with the requested data in a different way.
FTP (File Transfer Protocol)
FTP allows transferring of files from one host to another. Inherently insecure and is not recommended for any externally facing network unless used as a public, download-only resource.
DNS (Doman Name System)
DNS is an application layer protocol that provides a user friendly nomenclature system for resources on the internet.
SSH (Secure Shell)
SSH is an encrypted protocol implemented in the application layer that can be used to communicate with a remote server in a secure way. Many additional technologies are built around this protocol because of its end-to-end encryption and ubiquity.
Understanding the Internet
The Internet is by definition a global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols. Data is transmitted through computer networks that transmit data by packet switching using the standard Internet Protocol.
Origin of the Internet
The Internet’s origin has its roots in a military project—the Semi-Automatic Ground Environment (SAGE) program, which networked country-wide radar systems together for the first time. This was created around 1958 as part of an attempt to regain the lead in technology from the Soviet Union which had launched Sputnik. This was the beginning of the Advanced Research Projects Agency Network (ARPANET) which was one of the key networks which the Internet is based on.
Although the basic applications and guidelines that make the Internet possible had existed for almost a decade, the network did not gain public face until the 1990s. On August 6, 1991, the European Organization for Nuclear Research, (CERN), which straddles the border between France and Switzerland, publicized the new World Wide Web project. The web was invented by English scientist Tim Berners-Lee in 1989.
The world as it is today can’t be imagined without a network. Internet users now make up 57% of the global population. On average, people spend 6 hours and 42 minutes online each day. By 2021, a projected 73% of all ecommerce sales will come from mobile. Organizations are utilizing resources optimally and the demand for networks, strengthening and maintaining them will be one of their priorities.
D’autres effets secondaires, tels que les maux de tête, la diarrhée, l’insomnie et la fatigue, sont survenus, mais beaucoup moins fréquemment. En général, une utilisation combinée avec les psycho-pharmaceutiques et les antidépresseurs est essentielles. Demandez conseil à un médecin avant d’acheter le Priligy. cialispascherfr24.com Nous utilisons les cookies pour améliorer votre expérience.