Explain how a local area network differs from a wide area network in terms of the services it provides, the infrastructure it employs, and the way it is managed. Elucidate your familiarity with demarcation points like DTEs, CPEs, and DCEs by citing relevant real-world scenarios.

Elaborate on the functions of bridges in the OSI model and their role in connecting different network segments.

A broadcast network is one in which a transmission from any one attached station is received by all other attached stations over a shared medium. Examples are a bus topology local area network, such as Ethernet, and a wireless radio network. Discuss the need or lack of need for a network layer (OSI layer 3) in a broadcast network.