In network TCP IP address plays major roles. Without TCP even network will not work. To access the internet we need TCP address. TCP is required to send an email or chatting software or VPN connectivity. To get access or connect computer or desktop or workstation TCP plays major roles.
To send an email id we need from address and to address at the same time to send mail we need TCP and their router systems. To check whether we are connected to network router we use PING command in DOS MODE for that TCP IP address is required.