privilage level 15 indicates the level of access permitted by the enable password. which means the moment you type the telnet password, you need not have to type "enable" it will directly take you to # prompt.
login indicate which prompt the "login" prompt
"transport input telnet ssh", indicates that the interface will accepts both the telnet & ssh(secure shell login) which is more secure that the "telnet", so it is better to accept only the "ssh"
& finally line vty 0 4 indicates that the vty(virtual terminal) "0" means the interface number & "4" the maximum number of session to be opened for this interface, you can also have more that 4, which means concurrent sessions of this particular which will be opened. eg. if you say line vty 0 10, it can accept maximum of 11 concurrent sessions, bcoz the number starts from 0 to 10 = 11.
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...