88 ??
No
RADIUS requires port-based authentication.
TCP Port 88
Yes, RADIUS requires port-based authentication.
No, physically they are different numbers. Logically, however, both port 80 and port 8080 listen for HTTP traffic, so logically they are the same. Port 80 is the standard, production port for HTTP traffic. Port 8080 is a 'test' port for HTTP traffic.
Port-based authentication is a form of "security by obscurity" wherein any device connecting to a system via the selected port is assumed to have authority to access said system. This can be dangerous if the port is randomly guessed, or shared by an someone who has previously been authorized. In this way, port-based authentication is equivalent to using a weak (or even default) password.
The busiest port in the world is contested by several ports around the world as there is no standard measure of performance or volume of traffic. The main contenders are: Rotterdam Singapore Shanghai.
HTML itself doesn't use a port. You can transfer an HTML document over any port you'd like. The Hyper-text Transfer Protocol (HTTP) however, does have a standard, non-secure port: 80. Web servers listen by default at :80. If they're configured to listen for secure HTTPS connections, they will also listen on :443. Configuring the server to listen on a different port is often used to run two sites over the same domain name, and is pretty common on intranets.
LDAP uses port 389 for encrypted traffic.
RADIUS server
port 389
Port Authentication