Protocol: It is used to monitor the data transmission between the systems tcp/ip is a base protocol which is used to derive further protocols. Set of rules that Governs transmission of data.

TCP  - Transmission Control Protocol

FTP – File Transfer Protocol

SMTP - Simple Mail Transfer Protocol

HTTP – Hyper Text Transfer Protocol

HTTPS   - Secured Hyper Text Transfer Protocol (using SSL)

SOAP - Simple Object Access Protocol

WAP - Wireless Application Protocol

Port: It is a terminating/accessing/entry point to access the software/device/application.

http :  80/800

https : 443

SMTP : 25

ftp : 21 

The port number ranges between 0-65535. The application reserves the port number to avoid the port conflict. The ports and protocols are maintained in file/etc/services

Server: The system with high availability peripherals to serve the users is called a server. The operating system distinguishes between desktop and server version.

This server version provides a robust, scalable, consistent and reliable platform to host the applications, data bases etc.

Domain server: Used to host the domain in the company.

File server: It is used to provide file storage services in the company.

Mail server: Used to provide mail services for communication from internal and external users.

FTP server: Used to upload the files.

DHCP server: Used to release and renew IP addresses for all the systems that log on to the domain.

Web server: Provides web services in a company.

Print server: Used to host all the printers and provide collaborative print facilities to the users.

Client: It is a system which is used by end users to communicate with the servers.

Client can be a desktop/laptop/webtop/ device with installed software to communicate with server.

Ex: MS Outlook, outlook Express, internet Explorer, lotus notes, SAPGUI etc.

Client is software which contains a set of commands programs, executables, libraries that are used to communicate with servers. He is also referred as frontend to communicate with backend. Client requests and a server Responds. Client is referred as it service requester and server is referred as request processor. In a client server communication the clients are overloaded along with servers due to the following reasons.

1. There is no queue mechanism to process the request. The server has to handle the queue explicitly.
2. There's no inbuilt interpreters (client and server has to interpret separately). No intermediate interpreters.
3. There are no intermediate buffers/cache to reduce hits on the server. Every request hits server.
4. Every client is required DB client to communicate with server. There is a need to deploy and intermediate layer to address the above issues.

The above architecture is also referred as two tier architecture.