Many distributed applications have to be integrated into a customer's or corporation's existing network infrastructure. Requiring a specific network protocol would require an upgrade of all potential clients, which is simply unacceptable in most situations. Application developers have to take care in keeping the application as independent as possible of the underlying network infrastructure.
DCOM provides this abstraction transparently: DCOM can use any transport protocol, including TCP/IP, UDP, IPX/SPX and NetBIOS. DCOM provides a security framework on all of these protocols, including connectionless and connection-oriented protocols.
Developers can simply use the features provided by DCOM and be assured that their application is completely protocol-neutral.