As per the MCSE guide to Windows XP Professional second edition pg. 317 the answer is FTP.
tcp based protocols,internet protocol,sometimes file transfer protocol also supported by tcp wrappers. tcp is reliable and connection oriented.
The protocol is FTP and the port number 21 conquerorthecomputer.blogspot.com
TCP
TCP/IP is the standard default.
The SFTP port is used for secure logins, secure file transfer and port forwarding. It can be found on port 22 of the TCP protocol. The name of this port stands for Secure File Transfer Protocol.
When we send any data with the help of FTP over the internet , it usually transmit in plain text ....it means no encrption & anybody can easily read it .. But in SFTP , all the data encrypt & then transmit... Ftp works on port number 20 & 21 where 20 use for data & 21 use for control while SFTP works on port number 115. There are actually three SFTP protocols. 1. Serial File Transfer Protocol, a protocol used to transfer files between a PC and an embedded device using RS-232 or similar serial protocols. This protocol doesn't use a tcp/ip stack. 2. Simple File Transfer Protocol, an unsecured and rarely-used file transfer protocol from the early days of the Internet. This protocol uses tcp port 115. 3. Secure File Transfer Program, a network protocol designed to provide secure file transfer and manipulation facilities over SSH. This protocol uses tcp port 22 and is the more common meaning when using "SFTP".
You can use either TCP or UDP. If you need reliable connection use TCP otherwise UDP.
tcp/ip
Ftp is a file transfer protocol use with TCP/IP Protocol to transfer files directly to a server through the internet.
That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.That depends on the protocols used. TCP provides reliability, but if TCP is not used, higher-level protocols can include the reliability instead. That is to say, if a packet is not received, the higher-level protocol will take the responsibility of sending (or requesting) the packet again.For example, TFTP (Trivial File Transfer Protocol) uses UDP, and automatically resends a packet when an acknowledgement is not received after a certain time.
TCP (also sometimes called TCP/IP)
the protocol used for email is simple mail transfer protocol and the layer is transport layer.