Why do we say the IP protocol in TCP/IP suite is connectionless?

Question

Why is the IP called a connectionless protocol? If so, what is the connection-oriented protocol then?

Thanks.

Update - 1 - 20:21 2010/12/26

I think, to b

Answer 1

TCP is the connection part of TCP/IP. IP's the addressing.

Or, as an analogy, IP is the address written on the envelope, TCP is the postal system which uses the address as part of the work of getting the envelope from point A to point B.