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SSL or Secure Sockets Layer
I've always considered it to operate at the transport layer as it;s simply an encrypted version of TCP. However, Wikipedia OSI-model lists it as operating at the presentation layer, as it's concerned with the transformation of data between the application and transport layers.
UDP and TCP sockets are layer 4 ports which are associated with certain services, ie TCP80 refers to the HTTP (web) protocol, TCP443 refers to the HTTPS (SSL) secure protocol and TCP/UDP53 refers to DNS.
HTTPS ( Hypertext Transfer Protocol over SSL/TLS)
Use httpsThe game doesn't load if your TCP/IP connection is being reset all the time, which can be for a variety of reasons. An SSL connection (http over SSL = https) persists over many broken TCP/IP connections.
tftp
TELNET operates at Application Layer in TCP/IP Model. It's an Application to establish a connection to TCP Port Number 23, where a Telnet server application (telnetd) is listening.
2^16 bytes - size of TCP header
UDP does not require as much resources as TCP but in the same time, it does not insure delivery of packets.
The Application layer The Presentation layer The Session layer
UDP: DNS, TFTP, DHCP... TCP: SMTP, HTTP, HTTPS, DNS, FTP, SHH, Telnet...