Without applications, the network is not too useful. The applications are software programs that used to communicate over the network or process that giving access to the network. The application has two types, network application and application layer services.
The network applications are uses to communicate over the network. Some end-user applications apply application layer protocols and are able to communicate straight with the lower layers of the protocol stack. For example, Email clients is a network application.
Application Layer Services
Network print spooling and file transfer over the network is requisite application layer services to use network resources. These services are the software programs that interface with the network and organize the data for transfer. Several types of data e.g. text, graphics audio, and video are wanted different network services to make sure that the data is perfectly ready for processing.
Each application or network service uses protocols, which describe the standards and formats for data. There is no way to format data without common network protocols. Before understanding the role of network services, the understanding of protocols is very important. In the Windows operating system, we can view the current application, services, and running process as shown in the above figure. Following are the common protocols uses in networking:-
DNS was created to change the numeric address into a simple, recognizable name. The DNS is short for Domain Name System (or Service or Server).
Telnet is a service that allows network administrators to log in to a host remotely and control the host just like they are working locally.
SMTP, POP3, or IMAP are used to send email messages from clients to servers over the Internet.
DHCP is the service that assigns the IP address, subnet mask, default gateway, and other information to clients automatically.
Web server is transferring information and data between web clients and web servers. The majority of websites are accessing through HTTP (Hypertext Transfer Protocol)
The FTP service allows download and uploads files between a client and server
Voice and Video Applications
Streaming media is too much important for businesses to communicate with customers as well as their business partners. The network administrators must care about the equipment configuration, installation and it’s meet the requirements of real-time applications. The administrator also determines whether the present switches and cabling can support the traffic that will be added in the near future.
VOIP stands for Voice Over Internet Protocol. In common terms, VOIP is call service over the Internet.
VOIP is required a quality Internet connection for getting phone service through an Internet connection instead of the local phone company. We can also use VoIP with traditional phone service because VOIP service providers typically give low call rates than traditional phone services.
We can also use a traditional phone set using ATA (analogue telephone adapter) which converts the analogue signal into digital IP packets and vice versa. The administrator can attach the device between a traditional analogue phone and the Ethernet switch. VoIP is too much less expensive than an integrated IP telephony solution, but the quality does not meet the same standards
In IP telephony the ATA adapter is no more required because the IP phone itself performs the voice-to-IP conversion. The IP phones also use a separate server for call control and signalling.
A real-time application is a software program that works within a time frame that the user senses as current. This kind of software uses the Real-Time Transport Protocol (RTP) as well as Real-Time Transport Control Protocol (RTCP).
The QoS mechanism controls the latency of less than a defined value, which usually measured in seconds. For example, video conferencing application, online gaming, and video chatting are Real-time applications