Q&A

Q1:	What types of services are defined at the Network Access layer?
A1:	The Network Access layer includes services and specifications that manage the process of accessing the physical network.
Q2:	Which OSI layers correspond to the TCP/IP Network Access layer?
A2:	The Network Access layer roughly corresponds with the OSI Data Link layer and Physical layer.
Q3:	What are the two most common LAN architectures?
A3:	The most common LAN architectures are ethernet, with its several cabling variants, and token ring.
Q4:	What is CSMA/CD?
A4:	CSMA/CD is Carrier Sense Multiple Access with Collision Detect, a network access method used by ethernet. Under CSMA/CD, the computers on a network wait for a moment to transmit and, if two computers attempt to transmit at once, they both stop, wait for a random interval, and transmit again.
Q5:	What is token passing?
A5:	Token passing is a network-access method used by token ring and FDDI. A packet of data called a token circulates around the network. Only the computer with the token can transmit data.