Communication via TCP instead of HTTP for web services

Question

Hi all, I need help regarding WCF....  I have read that in we can WCF we can do communication in protocol independent manner i.e. we can use TCP instead of HTTP for web services...


Before reading WCF my concept was TCP is used for inter network communication and HTTP is used for accessing web sites, web services over the internet and intranet....

can some body tell me in which situation we need to use TCP rather then HTTP and what benefits we can achieve via this change??


any help in this regards would be heighly appreciated

thanks in advance.