How to design a wcf service for specific requirement

Question

i have 2 question on wcf.

 

1) suppose some one develop a bus booking service using wcf and expose the same service over 2 different endpoint like tcp and http but i like to know what would be the advantage of having 2 or more endpoint for single service ? in what kind of situation people use this trick? discuss in details.

 

 2) how can i offer some extra functionality for tcp client. suppose my service has 5 function but http client can call only 2 and tcp client can call all. how do i design wcf service in this way. any idea would be appreciated. thanks